U.S. patent application number 17/138604 was filed with the patent office on 2021-06-24 for nhe3-binding compounds and methods for inhibiting phosphate transport.
This patent application is currently assigned to Ardelyx, Inc.. The applicant listed for this patent is Ardelyx, Inc.. Invention is credited to Christopher Carreras, Dominique Charmot, Jeffrey W. Jacobs, Eric Labonte, Jason G. Lewis.
Application Number | 20210186953 17/138604 |
Document ID | / |
Family ID | 1000005436589 |
Filed Date | 2021-06-24 |
United States Patent
Application |
20210186953 |
Kind Code |
A1 |
Carreras; Christopher ; et
al. |
June 24, 2021 |
NHE3-BINDING COMPOUNDS AND METHODS FOR INHIBITING PHOSPHATE
TRANSPORT
Abstract
Provided are NHE3-binding and/or NHE3-modulating agents having
activity as phosphate transport inhibitors, including inhibitors of
phosphate transport in the gastrointestinal tract and the kidneys,
and methods for their use as therapeutic or prophylactic agent.
Inventors: |
Carreras; Christopher;
(Belmont, CA) ; Charmot; Dominique; (Campbell,
CA) ; Jacobs; Jeffrey W.; (San Mateo, CA) ;
Labonte; Eric; (Belmont, CA) ; Lewis; Jason G.;
(Castro Valley, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Ardelyx, Inc. |
Fremont |
CA |
US |
|
|
Assignee: |
Ardelyx, Inc.
Fremont
CA
|
Family ID: |
1000005436589 |
Appl. No.: |
17/138604 |
Filed: |
December 30, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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16351225 |
Mar 12, 2019 |
10940146 |
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17138604 |
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14783983 |
Oct 12, 2015 |
10272079 |
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PCT/US2014/033603 |
Apr 10, 2014 |
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16351225 |
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61888879 |
Oct 9, 2013 |
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61811613 |
Apr 12, 2013 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61K 47/545 20170801;
A61K 31/472 20130101; A61K 47/60 20170801; A61K 47/547 20170801;
A61K 31/4725 20130101; A61K 31/4545 20130101; A61K 47/54 20170801;
A61K 47/55 20170801 |
International
Class: |
A61K 31/4725 20060101
A61K031/4725; A61K 31/472 20060101 A61K031/472; A61K 47/55 20060101
A61K047/55; A61K 47/54 20060101 A61K047/54; A61K 47/60 20060101
A61K047/60; A61K 31/4545 20060101 A61K031/4545 |
Claims
1-18. (canceled)
19. A compound of Formula (I-H): ##STR00355## or a stereoisomer or
a pharmaceutically acceptable salt thereof, wherein: (a) n is an
integer of 2 or more; (b) Core is a Core moiety having two or more
sites thereon for attachment to two or more NHE-binding small
molecule moieties; (c) L is a bond or linker connecting the Core
moiety to the two or more NHE-binding small molecule moieties; and
(d) NHE is a NHE-binding small molecule moiety having the following
structure of Formula (XI-H): ##STR00356## wherein: B is selected
from the group consisting of aryl and heterocyclyl; each R is
independently selected from the group consisting of hydrogen,
halogen, optionally substituted C.sub.1-4alkyl, optionally
substituted C.sub.1-4alkoxy, optionally substituted
C.sub.1-4thioalkyl, optionally substituted heterocyclyl, optionally
substituted heterocyclylalkyl, optionally substituted aryl,
optionally substituted heteroaryl, hydroxyl, oxo, cyano, nitro,
--NR.sub.7R.sub.8, --NR.sub.7C(.dbd.O)R.sub.8,
--NR.sub.7C(.dbd.O)OR.sub.8, --NR.sub.7C(.dbd.O)NR.sub.8R.sub.9,
--NR.sub.7SO.sub.2R.sub.8, --NR.sub.7S(O).sub.2NR.sub.8R.sub.9,
--C(.dbd.O)OR.sub.7, --C(.dbd.O)R.sub.7,
--C(.dbd.O)NR.sub.7R.sub.8, --S(O).sub.1-2R.sub.7, and
--SO.sub.2NR.sub.7R.sub.8, wherein R.sub.7, R.sub.8, and R.sub.9
are independently selected from the group consisting of hydrogen,
C.sub.1-4alkyl, or a bond linking the NHE-binding small molecule
moiety to L, provided at least one is a bond linking the
NHE-binding small molecule moiety to L; R.sub.3 and R.sub.4 are
independently selected from the group consisting of hydrogen,
optionally substituted C.sub.1-4alkyl, optionally substituted
cycloalkyl, optionally substituted cycloalkylalkyl, optionally
substituted aryl, optionally substituted aralkyl, optionally
substituted heterocyclyl and optionally substituted heteroaryl; or
R.sub.3 and R.sub.4 form together with the nitrogen to which they
are bonded an optionally substituted 4-8 membered heterocyclyl; and
each R.sub.1 is independently selected from the group consisting of
hydrogen, halogen, optionally substituted C.sub.1-6alkyl and
optionally substituted C.sub.1-6alkoxy.
20. The compound, stereoisomer, or pharmaceutically acceptable salt
of claim 19, wherein NHE has Formula (XII-H): ##STR00357## wherein:
each R.sub.3 and R.sub.4 are independently selected from the group
consisting of hydrogen and optionally substituted C.sub.1-4alkyl,
or R.sub.3 and R.sub.4, taken together with the nitrogen to which
they are bonded, form an optionally substituted 4-8 membered
heterocyclyl; each R.sub.1 is independently selected from the group
consisting of hydrogen, halogen, C.sub.1-6alkyl, and
C.sub.1-6haloalkyl; and R.sub.5 is selected from the group
consisting of --SO.sub.2--NR.sub.7-- and --NHC(.dbd.O)NH--, wherein
R.sub.7 is hydrogen or C.sub.1-4alkyl.
21. The compound of claim 19, which is selected from the group
consisting of: ##STR00358## ##STR00359## ##STR00360## ##STR00361##
##STR00362## ##STR00363## ##STR00364## ##STR00365## ##STR00366##
##STR00367## or a pharmaceutically acceptable salt thereof.
22. A pharmaceutical composition comprising a compound,
stereoisomer, or pharmaceutically acceptable salt of claim 19 and a
pharmaceutically acceptable carrier, diluent, or excipient.
23. A method for inhibiting phosphate uptake in the
gastrointestinal tract of a patient in need of phosphate lowering,
comprising enterally administering to the patient the compound,
stereoisomer, or pharmaceutically acceptable salt as described in
claim 19.
24. A method for treating hyperphosphatemia in a subject in need
thereof comprising administering to the subject an effective amount
of the compound, stereoisomer, or pharmaceutically acceptable salt
as described in claim 19.
25. A compound of Formula (I-I): ##STR00368## or a stereoisomer or
a pharmaceutically acceptable salt thereof, wherein: (a) NHE is a
NHE-binding small molecule moiety having the following structure of
Formula (A-I): ##STR00369## wherein: each R.sub.1, R.sub.2,
R.sub.3, R.sub.5 and R.sub.9 are independently selected from H,
halogen, --NR.sub.7(CO)R.sub.8, --(CO)NR.sub.7R.sub.8,
--SO.sub.2--NR.sub.7R.sub.8, --NR.sub.7SO.sub.2R,
--NR.sub.7R.sub.8, --OR.sub.7, --SR.sub.7, --O(CO)NR.sub.7R.sub.8,
--NR.sub.7(CO)OR.sub.8, and --NR.sub.7SO.sub.2NR.sub.8, where
R.sub.7 and R.sub.8 are independently selected from H,
C.sub.1-6alkyl, --C.sub.1-6alkyl-OH or a bond linking the
NHE-binding small molecule to L, provided at least one is a bond
linking the NHE-binding small molecule to L; R.sub.4 is selected
from H, C.sub.1-C.sub.7 alkyl, or a bond linking the NHE-binding
small molecule to L; R.sub.6 is absent or selected from H and
C.sub.1-C.sub.7 alkyl; and Ar1 and Ar2 independently represent an
aromatic ring or a heteroaromatic ring; (b) Core is a Core moiety
having the following structure of Formula (B-I): ##STR00370##
wherein: X is selected from C(X.sub.1), N and N(C.sub.1-6alkyl);
X.sub.1 is selected from hydrogen, optionally substituted alkyl,
--NX.sub.aX.sub.b, --NO.sub.2,
--NX.sub.c--C(.dbd.O)--NX.sub.c--X.sub.a,
--C(.dbd.O)NX.sub.c--X.sub.a, --NX.sub.c--C(.dbd.O)--X.sub.a,
--NX.sub.c--SO.sub.2--X.sub.a, --C(.dbd.O)--X.sub.a and --OX.sub.a,
each X.sub.a and X.sub.b are independently selected from hydrogen,
optionally substituted alkyl, optionally substituted cycloalkyl,
optionally substituted cycloalkylalkyl, optionally substituted
heterocyclyl, optionally substituted heterocyclylalkyl, optionally
substituted aryl, optionally substituted aralkyl, optionally
substituted heteroaryl and optionally substituted heteroarylalkyl;
Y is C.sub.1-6alkylene; Z is selected from
--NZ.sub.a--C(.dbd.O)--NZ.sub.a--, --C(.dbd.O)NZ.sub.a--,
--NZ.sub.a--C(.dbd.O)-- and heteroaryl when X is CX.sub.1; Z is
selected from --NZ.sub.a--C(.dbd.O)--NZ.sub.a--,
--NZ.sub.a--C(.dbd.O)-- and heteroaryl when X is N or
N(C.sub.1-6alkyl); and each X.sub.c and Z.sub.a is independently
selected from hydrogen and C.sub.1-6alkyl; and (c) L is a bond or
linker connecting the Core moiety to the NHE-binding small molecule
moieties.
26. A pharmaceutical composition comprising a compound,
stereoisomer, or pharmaceutically acceptable salt of claim 25 and a
pharmaceutically acceptable carrier, diluent, or excipient.
27. A method for inhibiting phosphate uptake in the
gastrointestinal tract of a patient in need of phosphate lowering,
comprising enterally administering to the patient the compound,
stereoisomer, or pharmaceutically acceptable salt as described in
claim 25.
28. A method for treating hyperphosphatemia in a subject in need
thereof comprising administering to the subject an effective amount
of the compound, stereoisomer, or pharmaceutically acceptable salt
as described in claim 25.
29. A compound of Formula (II): ##STR00371## or a stereoisomer or a
pharmaceutically acceptable salt thereof, wherein: (a) NHE is a
NHE-binding small molecule moiety having the structure of Formula
(A-I): ##STR00372## wherein: each R.sub.1, R.sub.2, R.sub.3,
R.sub.5 and R.sub.9 are independently selected from H, halogen,
--NR.sub.7(CO)R.sub.8, --(CO)NR.sub.7R.sub.8,
--SO.sub.2--NR.sub.7R.sub.8, --NR.sub.7SO.sub.2R.sub.8,
--NR.sub.7R.sub.8, --OR.sub.7, --SR.sub.7, --O(CO)NR.sub.7R.sub.8,
--NR.sub.7(CO)OR.sub.8, and --NR.sub.7SO.sub.2NR.sub.8, where
R.sub.7 and R.sub.8 are independently selected from H,
C.sub.1-6alkyl, --C.sub.1-6alkyl-OH or a bond linking the
NHE-binding small molecule to L, provided at least one is a bond
linking the NHE-binding small molecule to L; R.sub.4 is selected
from H, C.sub.1-C.sub.7 alkyl, or a bond linking the NHE-binding
small molecule to L; R.sub.6 is absent or selected from H and
C.sub.1-C.sub.7 alkyl; and Ar1 and Ar2 independently represent an
aromatic ring or a heteroaromatic ring; (b) Core is a Core moiety
having the following structure of Formula (C-I): ##STR00373##
wherein: W is selected from alkylene, polyalkylene glycol
--C(.dbd.O)--NH-(alkylene)-NH--C(.dbd.O)--,
--C(.dbd.O)--NH-(polyalkylene glycol)-NH--C(.dbd.O)--,
--C(.dbd.O)-(alkylene)-C(.dbd.O)--, --C(.dbd.O)-(polyalkylene
glycol)-C(.dbd.O)-- and cycloalkyl, X is N; Y is C.sub.1-6alkylene;
Z is selected from --NZ.sub.a--C(.dbd.O)--NZ.sub.a--,
--C(.dbd.O)NZ.sub.a--, --NZ.sub.a--C(.dbd.O)-- and heteroaryl; each
Z.sub.a is independently selected from hydrogen and C.sub.1-6alkyl;
and (c) L is a bond or linker connecting the Core moiety to the
NHE-binding small molecules.
30. A pharmaceutical composition comprising a compound,
stereoisomer, or pharmaceutically acceptable salt of claim 29 and a
pharmaceutically acceptable carrier, diluent, or excipient.
31. A method for inhibiting phosphate uptake in the
gastrointestinal tract of a patient in need of phosphate lowering,
comprising enterally administering to the patient the compound,
stereoisomer, or pharmaceutically acceptable salt as described in
claim 29.
32. A method for treating hyperphosphatemia in a subject in need
thereof comprising administering to the subject an effective amount
of the compound, stereoisomer, or pharmaceutically acceptable salt
as described in claim 29.
33. A method for inhibiting phosphate uptake in the
gastrointestinal tract of a patient in need of phosphate lowering,
comprising enterally administering to the patient a compound of
Formula (X): ##STR00374## wherein NHE is ##STR00375## L is a
polyalkylene glycol linker; n is 2; and Core has is selected from:
##STR00376##
Description
RELATED APPLICATIONS
[0001] This application is a continuation application of U.S.
patent application Ser. No. 16/351,225 filed on Mar. 12, 2019,
which is a continuation application of U.S. patent application Ser.
No. 14/783,983, filed on Oct. 12, 2015, now U.S. Pat. No.
10,272,079, which is a 371 application of PCT/US2014/033603, filed
on Apr. 10, 2014, which claims the benefit of priority under 35
U.S.C. .sctn. 119(e) to U.S. Provisional Patent Application No.
61/888,879, filed on Oct. 9, 2013, and U.S. Provisional Patent
Application No. 61/811,613, filed on Apr. 12, 2013. The entire
content of the applications referenced above are hereby
incorporated by reference herein.
BACKGROUND
Technical Field
[0002] The present invention relates to NHE3-binding and/or
NHE3-modulating agents having activity as phosphate transport
inhibitors, including inhibitors of phosphate transport in the
gastrointestinal tract and the kidneys, and methods for their use
as therapeutic or prophylactic agents.
Description of the Related Art
[0003] Patients with inadequate renal function, hypoparathyroidism,
or certain other medical conditions (such as hereditary
hyperphosphatemia, Albright hereditary osteodystrophy, amyloidosis,
etc.) often have hyperphosphatemia, or elevated serum phosphate
levels (wherein the level, for example, is more than about 6
mg/dL). Hyperphosphatemia, especially if present over extended
periods of time, leads to severe abnormalities in calcium and
phosphorus metabolism, often manifested by secondary
hyperparathyroidism, bone disease and ectopic calcification in the
cardiovascular system, joints, lungs, eyes and other soft tissues.
Higher serum phosphorus levels are strongly associated with the
progression of renal failure, cardiovascular calcification and
mortality in end-stage renal disease (ESRD) patients. High-normal
serum phosphorus levels have been associated with cardiovascular
events and mortality among individuals who have chronic kidney
disease (CKD) and among those who have normal kidney function (see,
e.g., Joy et al., J. Manag. Care Pharm., 13(5):397-411 (2007)) The
progression of kidney disease can be slowed by reducing phosphate
retention. Thus, for renal failure patients who are
hyperphosphatemic and for chronic kidney disease patients who have
serum phosphate levels within the normal range or only slightly
elevated, therapy to reduce phosphate retention is beneficial.
[0004] For patients who experience hyperphosphatemia, calcium salts
have been widely used to bind intestinal phosphate and prevent its
absorption. Different types of calcium salts, including calcium
carbonate, acetate, citrate, alginate, and ketoacid salts have been
utilized for phosphate binding. However, these therapies often
cause hypercalcemia, a condition which results from absorption of
high amounts of ingested calcium. Hypercalcemia causes serious side
effects such as cardiac arrhythmias, renal failure, and skin and
vascular calcification. Frequent monitoring of serum calcium levels
is required during therapy with calcium-based phosphate binders.
Other calcium and aluminum-free phosphate binders, such as
sevelamer, a crosslinked polyamine polymer, have drawbacks that
include the amount and frequency of dosing required to be
therapeutically active. The relatively modest phosphate binding
capacity of those drugs in vivo obliges patients to escalate the
dose (up to 7 grs per day or more). Such quantities have been shown
to produce gastrointestinal discomfort, such as dyspepsia,
abdominal pain and, in some extreme cases, bowel perforation.
[0005] An alternative approach to the prevention of phosphate
absorption from the intestine in patients with elevated phosphate
serum levels is through inhibition of the intestinal transport
system which mediates phosphate uptake in the intestine. It is
understood that phosphate absorption in the upper intestine is
mediated at least in part by a carrier-mediated mechanism which
couples the absorption of phosphate to that of sodium. Inhibition
of intestinal phosphate transport will reduce body phosphorus
overload. In patients with advanced kidney disease (e.g. stage 4
and 5), the body phosphorus overload manifests itself by serum
phosphate concentration above normal levels, i.e.
hyperphosphatemia. Hyperphosphatemia is directly related to
mortality and morbidity. Inhibition of intestinal phosphate
transport will reduce serum phosphate concentration and therefore
improve outcome in those patients. In chronic kidney disease
patients at stage 2 or 3, the body phosphorus overload does not
necessarily lead to hyperphosphatemia, i.e., some patients remain
normophosphatemic, but there is a need to reduce or prevent body
phosphorus overload even at those early stages to avoid associated
bone and vascular disorders, and ultimately improve mortality rate.
Similarly, inhibition of intestinal phosphate transport would be
particularly advantageous in patients that have a disease that is
treatable by inhibiting the uptake of phosphate from the
intestines. Inhibition of phosphate absorption from the glomerular
filtrate within the kidneys would also be advantageous for treating
chronic renal failure. Furthermore, inhibition of phosphate
transport may slow the progression of renal failure and reduce risk
of cardiovascular events.
[0006] While progress has been made in this field, there remains a
need in the art for improved phosphate transport inhibitors. The
present invention fulfills this need and provides further related
advantages.
BRIEF SUMMARY
[0007] The present invention relates generally to NHE3-binding
and/or NHE-modulating compounds having activity as phosphate
transport inhibitors, including, for example, inhibitors of
phosphate transport in the gastrointestinal tract and the kidneys,
including stereoisomers, pharmaceutically acceptable salts and
prodrugs thereof, and the use of such compounds to inhibit
phosphate uptake and to thereby treat any of a variety of
conditions or diseases in which modulation of phosphate uptake
provides a therapeutic benefit.
[0008] Embodiments of the present invention include methods for
inhibiting phosphate uptake in the gastrointestinal tract or
kidneys of a patient in need of phosphate lowering, comprising
administering to the patient a compound that binds to NHE3 and is
substantially active in the gastrointestinal tract or kidneys to
inhibit transport of phosphate ions (Pi) therein upon
administration to the patient in need thereof.
[0009] Certain embodiments include methods for inhibiting phosphate
uptake in the gastrointestinal tract of a patient in need of
phosphate lowering, comprising enterally administering to the
patient a substantially systemically non-bioavailable compound that
binds to NHE3 and is substantially active in the gastrointestinal
tract to inhibit transport of phosphate ions (Pi) therein upon
administration to the patient in need thereof. In some embodiments,
the method is selected from one or more of (a) a method for
treating hyperphosphatemia, optionally postprandial
hyperphosphatemia; (b) a method for treating a renal disease,
optionally chronic kidney disease (CKD) or end-stage renal disease
(ESRD); (c) a method for reducing serum creatinine levels; (d) a
method for treating proteinuria; (e) a method for delaying time to
renal replacement therapy (RRT), optionally dialysis; (f) a method
for reducing FGF23 levels; (g) a method for reducing the
hyperphosphatemic effect of active vitamin D; (h) a method for
attenuating hyperparathyroidism, optionally secondary
hyperparathyroidism; (i) a method for reducing serum parathyroid
hormone (PTH); (j) a method for reducing inderdialytic weight gain
(IDWG); (k) a method for improving endothelial dysfunction,
optionally induced by postprandial serum phosphate; (1) a method
for reducing vascular calcification, optionally intima-localized
vascular calcification; (m) a method for reducing urinary
phosphorous; (n) a method for normalizing serum phosphorus levels;
(o) a method for reducing phosphate burden in an elderly patient;
(p) a method for decreasing dietary phosphate uptake; (q) a method
for reducing renal hypertrophy; (r) a method for reducing heart
hypertrophy; and (s) a method for treating obstructive sleep
apnea.
[0010] In some embodiments, the compound is substantially active on
the apical side of the epithelium of the gastrointestinal tract to
inhibit transport of Pi therein. In certain embodiments, the
compound is substantially impermeable to the epithelium of the
gastrointestinal tract.
[0011] In certain embodiments, upon administration of the compound
to the patient in need thereof, the compound exhibits a maximum
concentration detected in the serum, defined as C.sub.max, that is
less than the Pi transport inhibitory concentration IC.sub.50 of
the compound.
[0012] In some embodiments, systemic exposure to the compound is
less than 10% pIC.sub.50 at PD dose, with fecal recovery of greater
than about 80%, greater than about 90%, or greater than about 95%.
In certain embodiments, the compound is substantially active in the
small intestine to inhibit transport of Pi therein.
[0013] In certain embodiments, administration to the patient in
need thereof (a) reduces serum phosphate concentrations or levels
to about 150% or less of normal serum phosphate levels, and/or (b)
reduces uptake of dietary phosphorous by at least about 10%
relative to an untreated state. In some embodiments, administration
to the patient in need thereof reduces urinary phosphate
concentrations or levels by at least about 10% relative to an
untreated state. In certain embodiments, administration to the
patient in need thereof increases phosphate levels in fecal
excretion by at least about 10% relative to an untreated state.
[0014] In some embodiments, the compound is a persistent inhibitor
of NHE3-mediated antiport of sodium and hydrogen ions. In certain
embodiments, the compound is substantially active in the
gastrointestinal tract to inhibit NHE3-mediated antiport of sodium
and hydrogen ions therein upon administration to the patient in
need thereof. In some embodiments, the compound is substantially
active on the apical side of the epithelium of the gastrointestinal
tract to inhibit NHE3-mediated antiport of sodium ions and hydrogen
ions. In certain embodiments, the compound is substantially active
in the large intestine to inhibit NHE3-mediated antiport of sodium
and hydrogen ions therein upon administration to the patient in
need thereof.
[0015] In certain embodiments, persistent inhibition is
characterized by the time-dependent inhibitory activity of the
compound in an in vitro inhibition assay of NHE3-mediated antiport
of sodium and hydrogen ions, wherein the pIC.sub.50 of the compound
under prompt conditions (pIC.sub.50promp) is substantially
comparable to the pIC.sub.50 of the compound under persistent
conditions (pIC.sub.50pers). In some embodiments, persistent
inhibition is characterized by the time-dependent inhibitory
activity of the compound in an in vitro inhibition assay of
NHE3-mediated antiport of sodium and hydrogen ions, wherein the
pIC.sub.50 of the compound under prompt conditions
(pIC.sub.50promp) and under persistent conditions (pIC.sub.50pers)
is about or greater than about 7.0. In some embodiments, the
compound has an EC.sub.50 for increasing fecal output of phosphate
ions (EC.sub.50P.sub.f) and an EC.sub.50 for inhibiting
NHE3-mediated antiport of sodium and hydrogen ions (EC.sub.50Na)
that is defined by the formula EC.sub.50P.sub.f=(r)EC.sub.50Na,
wherein r is about 0.7 to about 1.3. In some embodiments, the
compound has an EC.sub.50 for reducing urinary output of phosphate
ions (EC.sub.50P.sub.u) and an EC.sub.50 for inhibiting
NHE3-mediated antiport of sodium and hydrogen ions (EC.sub.50Na)
that is defined by the formula EC.sub.50P.sub.u=(r)EC.sub.50Na,
wherein r is about 0.7 to about 1.3. In certain embodiments, the
compound has an EC.sub.50 for inhibiting transport of phosphate
ions (EC.sub.50P) and an EC.sub.50 for inhibiting NHE3-mediated
antiport of sodium and hydrogen ions (EC.sub.50Na) that is defined
by the formula EC.sub.50P=(r)EC.sub.50Na, wherein r is about 0.7 to
about 1.3.
[0016] In some embodiments, administration to the patient in need
thereof increases the patient's daily fecal output of sodium and/or
fluid. In certain embodiments, the compound, upon administration at
a dose resulting in at least about a 10% increase in fecal water
content, has a C.sub.max that is less than the IC.sub.50 for NHE3,
less than about 10.times. the IC.sub.50, or less than about
100.times. the IC.sub.50.
[0017] In certain embodiments, the patient in need thereof has
ESRD, and administration to the patient (a) reduces serum phosphate
concentrations or levels to about 150% or less of normal serum
phosphate levels, and (b) reduces inderdialytic weight gain (IDWG)
by at least about 10% relative to an untreated state.
[0018] In some embodiments, the patient in need thereof has CKD,
and administration to the patient (a) reduces FGF23 levels and
serum intact parathyroid hormone (iPTH) levels by at least about
10% relative to an untreated state, and (b) reduces blood pressure
and proteinuria by at least about 10% relative to an untreated
state.
[0019] In some embodiments, the compound is a non-persistent ligand
of NHE3. In certain embodiments, the compound has a maximum
inhibition of NHE3-mediated antiport of sodium and hydrogen ions of
less than about 50%, less than about 20%, or less than about 10%,
wherein maximum inhibition is characterized by the inhibitory
activity of the compound in an in vitro inhibition assay of
NHE3-mediated antiport of sodium and hydrogen ions and is relative
to sodium-free conditions. In some embodiments, the compound is
substantially inactive in the gastrointestinal tract to inhibit
NHE3-mediated antiport of sodium and hydrogen ions therein upon
administration to the patient in need thereof. In certain
embodiments, the compound is substantially inactive in the large
intestine to inhibit NHE3-mediated antiport of sodium and hydrogen
ions therein.
[0020] In certain embodiments, non-persistence is characterized by
the time-dependent inhibitory activity of the compound in an in
vitro inhibition assay of NHE3-mediated antiport of sodium and
hydrogen ions, wherein the pIC.sub.50 of the compound under prompt
conditions (pIC.sub.50promp) is (substantially) greater than the
pIC.sub.50 of the compound under persistent conditions
(pIC.sub.50pers). In some embodiments, non-persistence is
characterized by the time-dependent inhibitory activity of the
compound in an in vitro inhibition assay of NHE3-mediated antiport
of sodium and hydrogen ions, wherein the pIC.sub.50 of the compound
under prompt conditions (pIC.sub.50promp) is about or greater than
about 7.0, and wherein the pIC.sub.50 of the compound under
persistent conditions (pIC.sub.50pers) is about or less than about
6.0. In certain embodiments, the compound has an EC.sub.50 for
increasing fecal output of phosphate ions (EC.sub.50P.sub.f) and an
EC.sub.50 for inhibiting NHE3-mediated antiport of sodium and
hydrogen ions (EC.sub.50Na) that is defined by the formula
EC.sub.50P.sub.f=(r)EC.sub.50Na, wherein r is about 0.1 to about
0.5. In some embodiments, the compound has an EC.sub.50 for
reducing urinary output of phosphate ions (EC.sub.50P.sub.u) and an
EC.sub.50 for inhibiting NHE3-mediated antiport of sodium and
hydrogen ions (EC.sub.50Na) that is defined by the formula
EC.sub.50P.sub.u=(r)EC.sub.50Na, wherein r is about 0.1 to about
0.5. In some embodiments, the compound has an EC.sub.50 for
inhibiting transport of phosphate ions (EC.sub.50P) and an
EC.sub.50 for inhibiting NHE-mediated antiport of sodium and
hydrogen ions (EC.sub.50Na) that is defined by the formula
EC.sub.50P=(r)EC.sub.50Na, wherein r is about 0.1 to about 0.5.
[0021] In certain embodiments, administration to the patient in
need thereof increases the ratio of phosphate/sodium in fecal
excretion by at least about 10% relative to an untreated state. In
some embodiments, administration to the patient in need thereof
increases the daily fecal output of phosphate without substantially
modulating the stool form or water content of the feces. In certain
embodiments, administration to a rodent increases the ratio of
sodium in the small intestine (Na.sub.Si)/cecum (Na.sub.C) by at
least about 10% relative to an untreated state.
[0022] Also included are methods for increasing phosphaturia in a
patient in need of phosphate lowering, comprising administering to
the patient (a) a substantially systemically bioavailable compound,
or (b) a substantially systemically non-bioavailable compound via a
route excluding enteral administration; wherein the compound binds
to NHE3 and is substantially active in the kidneys to inhibit
transport of phosphate ions (Pi) therein upon administration to the
patient in need thereof. In some embodiments, the method is
selected from one or more of: (a) a method for treating
hyperphosphatemia, optionally postprandial hyperphosphatemia; (b) a
method for treating a renal disease, optionally chronic kidney
disease (CKD) or end-stage renal disease (ESRD); (c) a method for
reducing serum creatinine levels; (d) a method for treating
proteinuria; (e) a method for delaying time to renal replacement
therapy (RRT), optionally dialysis; (f) a method for reducing FGF23
levels; (g) a method for reducing the hyperphosphatemic effect of
active vitamin D; (h) a method for attenuating hyperparathyroidism,
optionally secondary hyperparathyroidism; (i) a method for reducing
serum parathyroid hormone (PTH); (j) a method for reducing
inderdialytic weight gain (IDWG); (k) a method for improving
endothelial dysfunction, optionally induced by postprandial serum
phosphate; (1) a method for reducing vascular calcification,
optionally intima-localized vascular calcification; (m) a method
for increasing urinary phosphorous; (n) a method for normalizing
serum phosphorus levels; (o) a method for reducing phosphate burden
in an elderly patient; (p) a method for decreasing dietary
phosphate uptake; (q) a method for reducing renal hypertrophy; (r)
a method for reducing heart hypertrophy; and (s) a method for
treating obstructive sleep apnea.
[0023] In some embodiments, the compound is substantially permeable
to the epithelium of the gastrointestinal tract. In certain
embodiments, administration to the patient in need thereof reduces
serum phosphate concentrations or levels to about 150% or less of
normal serum phosphate levels. In some embodiments, administration
to the patient in need thereof increases urinary phosphate
concentrations or levels by at least about 10% relative to an
untreated state.
[0024] In certain embodiments, the compound has (i) a tPSA of at
least about 200 .ANG..sup.2 and a molecular weight of at least
about 710 Daltons in the non-salt form, or (ii) a tPSA of at least
about 270 .ANG..sup.2. In certain embodiments, the compound has a
tPSA of at least about 250 .ANG..sup.2, or a tPSA of at least about
270 .ANG..sup.2, or a tPSA of at least about 300 .ANG..sup.2, or a
tPSA of at least about 350 .ANG..sup.2, or a tPSA of at least about
400 .ANG..sup.2, or a tPSA of at least about 500 .ANG..sup.2. In
certain embodiments, the compound has a molecular weight of at
least about 500 Da, or a molecular weight of at least about 1000
Da, or a molecular weight of at least about 2500 Da, or a molecular
weight of at least about 5000 Da.
[0025] In some embodiments, the compound has (i) a total number of
NH and/or OH and/or other potential hydrogen bond donor moieties
greater than about 5; (ii) a total number of O atoms and/or N atoms
and/or other potential hydrogen bond acceptors greater than about
10; and/or (iii) a Moriguchi partition coefficient greater than
about 10.sup.5 or less than about 10. In certain embodiments, the
compound has a permeability coefficient, P.sub.app, of less than
about 100.times.10.sup.-6 cm/s, or less than about
10.times.10.sup.-6 cm/s, or less than about 1.times.10.sup.-6 cm/s,
or less than about 0.1.times.10.sup.-6 cm/s.
[0026] In some embodiments, the compound has a structure of Formula
(I) or (IX):
##STR00001##
wherein: NHE is a NHE-binding small molecule that comprises (i) a
hetero-atom containing moiety, and (ii) a cyclic or heterocyclic
scaffold or support moiety bound directly or indirectly thereto,
the heteroatom-containing moiety being selected from a substituted
guanidinyl moiety and a substituted heterocyclic moiety, which may
optionally be fused with the scaffold or support moiety to form a
fused bicyclic structure; and, Z is a moiety having at least one
site thereon for attachment to the NHE-binding small molecule, the
resulting NHE-Z molecule possessing overall physicochemical
properties that render it substantially impermeable or
substantially systemically non-bioavailable; and, E is an integer
having a value of 1 or more.
[0027] In some embodiments, the compound is an oligomer, dendrimer
or polymer, and further wherein Z is a Core moiety having two or
more sites thereon for attachment to multiple NHE-binding small
molecules, either directly or indirectly through a linking moiety,
L, the compound having the structure of Formula (X):
##STR00002##
wherein L is a bond or linker connecting the Core to the
NHE-binding small molecule, and n is an integer of 2 or more, and
further wherein each NHE-binding small molecule may be the same or
differ from the others, or a pharmaceutically acceptable salt
thereof.
[0028] In certain embodiments, the total number of freely rotatable
bonds in the NHE-Z molecule is at least about 10. In certain
embodiments, the total number hydrogen bond donors in the NHE-Z
molecule is at least about 5. In some embodiments, the total number
of hydrogen bond acceptors in the NHE-Z molecule is at least about
10. In certain embodiments, the total number of hydrogen bond
donors and hydrogen bond acceptors in the NHE-Z molecule is at
least about 10. In some embodiments, the Log P of the NHE-Z binding
compound is at least about 5. In certain embodiments, the log P of
the NHE-Z binding compound is less than about 1, or less than about
0. In certain embodiments, the scaffold is a 5-member or 6-member
cyclic or heterocyclic moiety. In certain embodiments, the scaffold
is aromatic.
[0029] In some embodiments, the scaffold of the NHE-binding small
molecule is bound to the moiety, Z, the compound having the
structure of Formula (II):
##STR00003##
[0030] wherein: Z is a Core having one or more sites thereon for
attachment to one or more NHE-binding small molecules, the
resulting NHE-Z molecule possessing overall physicochemical
properties that render it substantially impermeable or
substantially systemically non-bioavailable; B is the
heteroatom-containing moiety of the NHE-binding small molecule, and
is selected from a substituted guanidinyl moiety and a substituted
heterocyclic moiety, which may optionally be fused with the
Scaffold moiety to form a fused, bicyclic structure; Scaffold is
the cyclic or heterocyclic scaffold or support moiety of the
NHE-binding small molecule, which is bound directly or indirectly
to heteroatom-containing moiety, B, and which is optionally
substituted with one or more additionally hydrocarbyl or
heterohydrocarbyl moieties; X is a bond or a spacer moiety selected
from a group consisting of substituted or unsubstituted hydrocarbyl
or heterohydrocarbyl moieties, and in particular substituted or
unsubstituted C.sub.1-7 hydrocarbyl or heterohydrocarbyl, and
substituted or unsubstituted, saturated or unsaturated, cyclic or
heterocyclic moieties, which links B and the Scaffold; and D and E
are integers, each independently having a value of 1 or more.
[0031] In some embodiments, the NHE-binding small molecule has the
structure of Formula (IV):
##STR00004##
or a stereoisomer, prodrug or pharmaceutically acceptable salt
thereof, wherein: each R.sub.1, R.sub.2, R.sub.3, R.sub.5 and
R.sub.9 are independently selected from H, halogen,
--NR.sub.7(CO)R.sub.8, --(CO)NR.sub.7R.sub.8,
--SO.sub.2--NR.sub.7R.sub.8, --NR.sub.7SO.sub.2R.sub.8,
--NR.sub.7R.sub.8, --OR.sub.7, --SR.sub.7, --O(CO)NR.sub.7R.sub.8,
--NR.sub.7(CO)OR.sub.8, and --NR.sub.7SO.sub.2NR.sub.8, where
R.sub.7 and R.sub.8 are independently selected from H or a bond
linking the NHE-binding small molecule to L, provided at least one
is a bond linking the NHE-binding small molecule to L; R.sub.4 is
selected from H, C.sub.1-C.sub.7 alkyl, or a bond linking the
NHE-binding small molecule to L; R.sub.6 is absent or selected from
H and C.sub.1-C.sub.7 alkyl; and Ar1 and Ar2 independently
represent an aromatic ring or a heteroaromatic ring.
[0032] In certain embodiments, the NHE-binding small molecule has
the following structure:
##STR00005##
or a stereoisomer, prodrug or pharmaceutically acceptable salt
thereof, wherein: each R.sub.1, R.sub.2 and R.sub.3 are
independently selected from H, halogen, --NR(CO)R,
--(CO)NR.sub.7R.sub.8, --SO.sub.2--NR.sub.7R.sub.8,
--NR.sub.7SO.sub.2R.sub.8, --NR.sub.7R.sub.8, --OR.sub.7,
--SR.sub.7, --O(CO)NR.sub.7R.sub.8, --NR.sub.7(CO)OR.sub.8, and
--NR.sub.7SO.sub.2NR.sub.8, where R.sub.7 and R.sub.8 are
independently selected from H or a bond linking the NHE-binding
small molecule to L, provided at least one is a bond linking the
NHE-binding small molecule to L.
[0033] In some embodiments, the NHE-binding small molecule has one
of the following structures:
##STR00006##
or a stereoisomer, prodrug or pharmaceutically acceptable salt
thereof. In certain embodiments, L is a polyalkylene glycol linker.
In certain embodiments, L is a polyethylene glycol linker. In some
embodiments, n is 2.
[0034] In certain embodiments, the Core has the following
structure:
##STR00007##
wherein: X is selected from the group consisting of a bond, --O--,
--NH--, --S--, C.sub.1-6alkylene, --NHC(.dbd.O)--, --C(.dbd.O)NH--,
--NHC(.dbd.O)NH--, --SO.sub.2NH--, and --NHSO.sub.2--; Y is
selected from the group consisting of a bond, optionally
substituted C.sub.1-8alkylene, optionally substituted aryl,
optionally substituted heteroaryl, a polyethylene glycol linker,
--(CH.sub.2).sub.1-6O(CH.sub.2).sub.1-6-- and
--(CH.sub.2).sub.1-6NY.sub.1(CH.sub.2).sub.1-6--; and Y.sub.1 is
selected from the group consisting of hydrogen, optionally
substituted C.sub.1-8alkyl, optionally substituted aryl or
optionally substituted heteroaryl, or a pharmaceutically acceptable
salt thereof.
[0035] In some embodiments, the Core is selected from the group
consisting of:
##STR00008##
[0036] In some embodiments, the compound has the following
structure of Formula (I-H):
##STR00009##
or a stereoisomer, prodrug or pharmaceutically acceptable salt
thereof, wherein: (a) n is an integer of 2 or more; (b) Core is a
Core moiety having two or more sites thereon for attachment to two
or more NHE-binding small molecule moieties; (c) L is a bond or
linker connecting the Core moiety to the two or more NHE-binding
small molecule moieties; and (d) NHE is a NHE-binding small
molecule moiety having the following structure of Formula
(XI-H):
##STR00010##
wherein: B is selected from the group consisting of aryl and
heterocyclyl; each R.sub.5 is independently selected from the group
consisting of hydrogen, halogen, optionally substituted
C.sub.1-4alkyl, optionally substituted C.sub.1-4alkoxy, optionally
substituted C.sub.1-4thioalkyl, optionally substituted
heterocyclyl, optionally substituted heterocyclylalkyl, optionally
substituted aryl, optionally substituted heteroaryl, hydroxyl, oxo,
cyano, nitro, --NR.sub.7R.sub.8, --NR.sub.7C(.dbd.O)R.sub.8,
--NR.sub.7C(.dbd.O)OR.sub.8, --NR.sub.7C(.dbd.O)NR.sub.8R.sub.9,
--NR.sub.7SO.sub.2R.sub.8, --NR.sub.7S(O).sub.2NR.sub.8R.sub.9,
--C(.dbd.O)OR.sub.7, --C(.dbd.O)R.sub.7,
--C(.dbd.O)NR.sub.7R.sub.8, --S(O).sub.1-2R.sub.7, and
--SO.sub.2NR.sub.7R.sub.8, wherein R.sub.7, R.sub.8, and R.sub.9
are independently selected from the group consisting of hydrogen,
C.sub.1-4alkyl, or a bond linking the NHE-binding small molecule
moiety to L, provided at least one is a bond linking the
NHE-binding small molecule moiety to L; R.sub.3 and R.sub.4 are
independently selected from the group consisting of hydrogen,
optionally substituted C.sub.1-4alkyl, optionally substituted
cycloalkyl, optionally substituted cycloalkylalkyl, optionally
substituted aryl, optionally substituted aralkyl, optionally
substituted heterocyclyl and optionally substituted heteroaryl; or
R.sub.3 and R.sub.4 form together with the nitrogen to which they
are bonded an optionally substituted 4-8 membered heterocyclyl; and
each R.sub.1 is independently selected from the group consisting of
hydrogen, halogen, optionally substituted C.sub.1-6alkyl and
optionally substituted C.sub.1-6alkoxy. In some embodiments, n is
2. In certain embodiments, L is a polyalkylene glycol linker. In
certain embodiments, L is a polyethylene glycol linker.
[0037] In certain embodiments, the Core has the following
structure:
##STR00011##
wherein: X is selected from the group consisting of a bond, --O--,
--NH--, --S--, C.sub.1-6alkylene, --NHC(.dbd.O)--, --C(.dbd.O)NH--,
--NHC(.dbd.O)NH--, --SO.sub.2NH--, and --NHSO.sub.2--; Y is
selected from the group consisting of a bond, optionally
substituted C.sub.1-8alkylene, optionally substituted aryl,
optionally substituted heteroaryl, a polyethylene glycol linker,
--(CH.sub.2).sub.1-6O(CH.sub.2).sub.1-6-- and
--(CH.sub.2).sub.1-6NY(CH.sub.2).sub.1-6--; and Y.sub.1 is selected
from the group consisting of hydrogen, optionally substituted
C.sub.1-8alkyl, optionally substituted aryl or optionally
substituted heteroaryl, or a pharmaceutically acceptable salt
thereof.
[0038] In some embodiments, the Core is selected from the group
consisting of
##STR00012## ##STR00013##
[0039] In certain embodiments, the NHE-binding small molecule
moiety has the following structure of Formula (XII-H):
##STR00014##
wherein: each R.sub.3 and R.sub.4 are independently selected from
the group consisting of hydrogen and optionally substituted
C.sub.1-4alkyl, or R.sub.3 and R.sub.4, taken together with the
nitrogen to which they are bonded, form an optionally substituted
4-8 membered heterocyclyl; each R.sub.1 is independently selected
from the group consisting of hydrogen, halogen, C.sub.1-6alkyl, and
C.sub.1-6haloalkyl; and R.sub.5 is selected from the group
consisting of --SO.sub.2--NR.sub.7-- and --NHC(.dbd.O)NH--, wherein
R.sub.7 is hydrogen or C.sub.1-4alkyl.
[0040] In some embodiments, R.sub.3 and R.sub.4, taken together
with the nitrogen to which they are bonded, form an optionally
substituted 5 or 6 membered heterocyclyl. In certain embodiments,
the optionally substituted 5 or 6 membered heterocyclyl is
pyrrolidinyl or piperidinyl. In certain embodiments, the optionally
substituted 5 or 6 membered heterocyclyl is pyrrolidinyl or
piperidinyl, each substituted with at least one amino or hydroxyl.
In some embodiments, R.sub.3 and R.sub.4 are independently
C.sub.1-4alkyl. In certain embodiments, R.sub.3 and R.sub.4 are
methyl. In some embodiments, each R.sub.1 is independently selected
from the group consisting of hydrogen or halogen. In certain
embodiments, each R.sub.1 is independently selected from the group
consisting of hydrogen, F and Cl.
[0041] In certain embodiments, the compound has the following
structure of Formula (I-I):
##STR00015##
or a stereoisomer, prodrug or pharmaceutically acceptable salt
thereof, wherein: (a) NHE is a NHE-binding small molecule moiety
having the following structure of Formula (A-I):
##STR00016##
wherein: each R.sub.1, R.sub.2, R.sub.3, R.sub.5 and R.sub.9 are
independently selected from H, halogen, --NR.sub.7(CO)R.sub.8,
--(CO)NR.sub.7R.sub.8, --SO.sub.2--NR.sub.7R.sub.8,
--NR.sub.7SO.sub.2R.sub.8, --NR.sub.7R.sub.8, --OR, --SR,
--O(CO)NR.sub.7R.sub.8, --NR.sub.7(CO)OR.sub.8, and
--NR.sub.7SO.sub.2NR.sub.8, where R.sub.7 and R.sub.8 are
independently selected from H, C.sub.1-6alkyl, --C.sub.1-6alkyl-OH
or a bond linking the NHE-binding small molecule to L, provided at
least one is a bond linking the NHE-binding small molecule to L;
R.sub.4 is selected from H, C.sub.1-C.sub.7 alkyl, or a bond
linking the NHE-binding small molecule to L; R.sub.6 is absent or
selected from H and C.sub.1-C.sub.7 alkyl; and Ar1 and Ar2
independently represent an aromatic ring or a heteroaromatic ring;
(b) Core is a Core moiety having the following structure of Formula
(B-I):
##STR00017##
wherein: X is selected from C(X.sub.1), N and N(C.sub.1-6alkyl);
X.sub.1 is selected from hydrogen, optionally substituted alkyl,
--NX.sub.aX.sub.b, --NO.sub.2,
--NX.sub.c--C(.dbd.O)--NX.sub.c--X.sub.a,
--C(.dbd.O)NX.sub.c--X.sub.a, --NX.sub.c--C(.dbd.O)--X.sub.a,
--NX.sub.c--SO.sub.2--X.sub.a, --C(.dbd.O)--X.sub.a and --OX.sub.a,
each X.sub.a and X.sub.b are independently selected from hydrogen,
optionally substituted alkyl, optionally substituted cycloalkyl,
optionally substituted cycloalkylalkyl, optionally substituted
heterocyclyl, optionally substituted heterocyclylalkyl, optionally
substituted aryl, optionally substituted aralkyl, optionally
substituted heteroaryl and optionally substituted heteroarylalkyl;
Y is C.sub.1-6alkylene; Z is selected from
--NZ.sub.a--C(.dbd.O)--NZ.sub.a--, --C(.dbd.O)NZ.sub.a,
--NZ.sub.aC(.dbd.O)-- and heteroaryl when X is CX; Z is selected
from --NZ.sub.a--C(.dbd.O)--NZ.sub.a--, --NZ.sub.aC(.dbd.O)-- and
heteroaryl when X is N or N(C.sub.1-6alkyl); and each X.sub.c and
Z.sub.a is independently selected from hydrogen and C.sub.1-6alkyl;
and (c) L is a bond or linker connecting the Core moiety to the
NHE-binding small molecule moieties.
[0042] In some embodiments, the NHE-binding small molecule moiety
has the following structure:
##STR00018##
wherein: each R.sub.1, R.sub.2 and R.sub.3 are independently
selected from H, halogen, --NR.sub.7(CO)R.sub.8,
--(CO)NR.sub.7R.sub.8, --SO.sub.2--NR.sub.7R.sub.8,
--NR.sub.7SO.sub.2R.sub.8, --NR.sub.7R.sub.8, --OR.sub.7,
--SR.sub.7, --O(CO)NR.sub.7R.sub.8, --NR.sub.7(CO)OR.sub.8, and
--NR.sub.7SO.sub.2NR.sub.8, where R.sub.7 and R.sub.8 are
independently selected from H, C.sub.1-6alkyl, --C.sub.1-6alkyl-OH
or a bond linking the NHE-binding small molecule to L, provided at
least one is a bond linking the NHE-binding small molecule to
L.
[0043] In some embodiments, the NHE-binding small molecule moiety
has one of the following structures:
##STR00019##
[0044] In some embodiments, L is a polyalkylene glycol linker. In
certain embodiments, L is a polyethylene glycol linker. In some
embodiments, X is C(X.sub.1). In some embodiments, each X.sub.c is
hydrogen. In certain embodiments, X is N. In certain embodiments,
each Z.sub.a is hydrogen.
[0045] In some embodiments, the compound has the structure of
Formula (II-I):
##STR00020##
or a stereoisomer, prodrug or pharmaceutically acceptable salt
thereof, wherein: (a) NHE is a NHE-binding small molecule moiety
having the structure of Formula (A-I):
##STR00021##
wherein: each R.sub.1, R.sub.2, R.sub.3, R.sub.5 and R.sub.9 are
independently selected from H, halogen, --NR.sub.7(CO)R.sub.8,
--(CO)NR.sub.7R.sub.8, --SO.sub.2--NR.sub.7R.sub.8,
--NR.sub.7SO.sub.2R.sub.8, --NR.sub.7R.sub.8, --OR.sub.7,
--SR.sub.7, --O(CO)NR.sub.7R.sub.8, --NR.sub.7(CO)OR, and
--NR.sub.7SO.sub.2NR.sub.8, where R.sub.7 and R.sub.8 are
independently selected from H, C.sub.1-6alkyl, --C.sub.1-6alkyl-OH
or a bond linking the NHE-binding small molecule to L, provided at
least one is a bond linking the NHE-binding small molecule to L;
R.sub.4 is selected from H, C.sub.1-C.sub.7 alkyl, or a bond
linking the NHE-binding small molecule to L; R.sub.6 is absent or
selected from H and C.sub.1-C.sub.7 alkyl; and Ar1 and Ar2
independently represent an aromatic ring or a heteroaromatic ring;
(b) Core is a Core moiety having the following structure of Formula
(C-I):
##STR00022##
wherein: W is selected from alkylene, polyalkylene glycol,
--C(.dbd.O)--NH-(alkylene)-NH--C(.dbd.O)--,
--C(.dbd.O)--NH-(polyalkylene glycol)-NH--C(.dbd.O)--,
--C(.dbd.O)-(alkylene)-C(.dbd.O)--, --C(.dbd.O)-(polyalkylene
glycol)-C(.dbd.O)-- and cycloalkyl; X is N; Y is C.sub.1-6alkylene;
Z is selected from --NZ.sub.a--C(.dbd.O)--NZ.sub.a--,
--C(.dbd.O)NZ.sub.a, --NZ.sub.aC(.dbd.O)-- and heteroaryl; each
Z.sub.a is independently selected from hydrogen and C.sub.1-6alkyl;
and (c) L is a bond or linker connecting the Core moiety to the
NHE-binding small molecules.
[0046] In certain embodiments, the NHE-binding small molecule
moiety has the following structure:
##STR00023##
wherein: each R.sub.1, R.sub.2 and R.sub.3 are independently
selected from H, halogen, --NR.sub.7(CO)R.sub.8,
--(CO)NR.sub.7R.sub.8, --SO.sub.2--NR.sub.7R.sub.8,
--NR.sub.7SO.sub.2R.sub.8, --NR.sub.7R.sub.8, --OR.sub.7,
--SR.sub.7, --O(CO)NR.sub.7R.sub.8, --NR.sub.7(CO)OR.sub.8, and
--NR.sub.7SO.sub.2NR.sub.8, where R.sub.7 and R.sub.8 are
independently selected from H, C.sub.1-6alkyl, --C.sub.1-6alkyl-OH
or a bond linking the NHE-binding small molecule to L, provided at
least one is a bond linking the NHE-binding small molecule to
L.
[0047] In certain embodiments, the NHE-binding small molecule
moiety has one of the following structures:
##STR00024##
[0048] In specific embodiments, the compound is selected from a
compound of Table E3 or Table E4, or a pharmaceutically acceptable
salt thereof.
[0049] In particular embodiments, the compound is:
##STR00025##
or a pharmaceutically acceptable salt thereof.
[0050] In particular embodiments, the compound is:
##STR00026##
[0051] Certain methods further comprise administering one or more
additional biologically active agents. In certain embodiments, the
compound and the one or more additional biologically active agents
are administered as part of a single pharmaceutical composition. In
some embodiments, the compound and the one or more additional
biologically active agents are administered as individual
pharmaceutical compositions. In some embodiments, the individual
pharmaceutical compositions are administered sequentially. In some
embodiments, the individual pharmaceutical compositions are
administered simultaneously.
[0052] In certain embodiments, the additional biologically active
agent is selected from vitamin D.sub.2 (ergocalciferol), vitamin
D.sub.3 (cholecalciferol), active vitamin D (calcitriol) and active
vitamin D analogs (e.g. doxercalciferol, paricalcitol).
[0053] In some embodiments, the additional biologically active
agent is a phosphate binder.
[0054] In certain embodiments, the phosphate binder is selected
from the group consisting of sevelamer (e.g., Renvela.RTM.
(sevelamer carbonate), Renagel.RTM. (sevelamer hydrochloride)),
lanthanum carbonate (e.g., Fosrenol.RTM.), calcium carbonate (e.g.,
Calcichew.RTM., Titralac.RTM.), calcium acetate (e.g. PhosLo.RTM.,
Phosex.RTM.), calcium acetate/magnesium carbonate (e.g.,
Renepho.RTM., OsvaRen.RTM.), MCI-196, ferric citrate (e.g.,
Zerenex.TM.), magnesium iron hydroxycarbonate (e.g.,
Fermagate.RTM.), aluminum hydroxide (e.g., Alucaps.RTM.,
Basaljel.RTM.), APS1585, SBR-759, and PA-21.
[0055] In some embodiments, the additional biologically active
agent is a NaPi2b inhibitor. In certain embodiments, the additional
biologically active agent is niacin or nicotinamide.
[0056] In some embodiments, the compound or composition is
administered orally. In certain embodiments, the compound or
composition is administered orally once-a-day.
[0057] These and other aspects of the invention will be apparent
upon reference to the following detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0058] FIGS. 1A-B shows the effects of test compounds on reducing
phosphate uptake in normal-function rats (see Example 3). FIG. 1A
shows that Cpd 004, a non-persistent NHE3 inhibitor, was as potent
at reducing Pi uptake as a persistent inhibitor such as Cpd 003.
FIGS. 1B-C show that Cpd 003 significantly reduced Pi uptake in the
presence of glucose/Ca (1B) and Ca (1C).
[0059] FIG. 2 shows the study design for testing the activity of
compounds in a rat model of uremia-associated vascular
calcification.
[0060] FIGS. 3A-F show the base-line body weight (3A) and serum
parameters (serum phosphorus (3B); serum calcium (3C); serum
creatinine (3D); blood urea nitrogen (3E-F)) in the rat model of
uremia-associated vascular calcification.
[0061] FIGS. 4A-F show the effects of test compound on serum
parameters (plasma creatinine (4A); blood urea nitrogen (4B);
plasma albumin (4C); plasma phosphorus (4D); plasma calcium (4E);
and plasma FGF23 (4F)) in the rat model of uremia-associated
vascular calcification. These results show that test compound
significant reduced plasma creatinine, plasma phosphorus, and
plasma FGF23. Test compound also significantly increased plasma
albumin, and a slightly increased plasma calcium.
[0062] FIG. 5 shows the effects of test compound on the endpoint
heart and kidney remnant weights in the rat model of
uremia-associated vascular calcification. Administration of test
compound significantly reduced the organ weight/body weight values
for heart and kidney.
[0063] FIGS. 6A-B show the effects of test compound on endpoint
creatinine clearance (C.sub.Cr) and plasma aldosterone levels in
the rat model of uremia-associated vascular calcification.
Administration of test compound maintained creatinine clearance
relative to vehicle-only and also significantly increased plasma
aldosterone.
[0064] FIGS. 7A-B show the effects of test compound on endpoint
vascular and soft tissue calcification in the rat model of
uremia-associated vascular calcification. Administration of test
compound significantly reduced the stomach and aortic mineral
content of phosphorus and calcium.
[0065] FIG. 8A shows the study design for testing the activity of
compounds in an adenine-induced uremic rat model. FIGS. 8B-C show
that test compound significantly reduced serum phosphorus and serum
creatinine at early time points in this model of acute renal
injury.
[0066] FIGS. 9A-B show the organ weight collection data from week
three of the adenine-induced uremic rat model. Administration of
test compound showed a tendency to reduce heart and kidney
remodeling.
[0067] FIGS. 10A-B show the tissue mineralization data from week
three of the adenine-induced uremic rat model. Administration of
test compound reduced heart and kidney calcification at the highest
dose (5 mpk).
[0068] FIG. 11A shows the study design for testing the activity of
compounds in dietary salt-induced, partial renal ablation model of
chronic kidney disease (CKD). FIG. 11B shows the effects of test
compound on urinary excretion of phosphorus.
[0069] FIG. 12 shows the study design for testing the activity of
test compound on urinary excretion of phosphate and calcium in
rats.
[0070] FIGS. 13A-D show that administration of test compound
reduced both urine phosphorus mass and urine calcium mass relative
to the vehicle-only control. Increasing dosages of test compound
also significantly reduced urine phosphorus mass relative to 48
mg/kg Renvela.RTM..
[0071] FIGS. 14A-B show the mean average daily fecal excretion of
Na (14A; +/-SE) and phosphorus (14B; +/-). Excretion data were
averaged over the 7-day treatment period (Day 1 to Day 7) and
reported as mEq/day (see Example 8). Statistical analysis was
performed by one-way ANOVA; (*); p<0.05, (**); p<0.01, (***);
p<0.001.
[0072] FIGS. 15A-C show the mean average daily fecal excretion of
phosphorus (15A; +/-SE) and the mean average daily urinary
excretion of sodium (15B; +/-SE) and phosphorus (15C; +/-) (see
Example 9). Statistical analysis performed by one-way ANOVA; (*);
p<0.05, (**); p<0.01, (***); p<0.001.
[0073] FIGS. 16A-B shown the mean average daily fecal excretion of
sodium (16A; +/-SE) and the mean average daily fecal excretion of
phoshorus (16B; +/-SE) (see Example 10). Statistical analysis
performed by one-way ANOVA followed by Tukey's multiple
comparison's test; (*); p<0.05, (**); p<0.01, (***);
p<0.001. vs. pre-Dose.
DETAILED DESCRIPTION
[0074] In the following description, certain specific details are
set forth in order to provide a thorough understanding of various
embodiments of the invention. However, one skilled in the art will
understand that the invention may be practiced without these
details.
[0075] Unless the context requires otherwise, throughout the
present specification and claims, the word "comprise" and
variations thereof, such as, "comprises" and "comprising" are to be
construed in an open, inclusive sense, that is, as "including, but
not limited to".
[0076] Reference throughout this specification to "one embodiment"
or "an embodiment" means that a particular feature, structure or
characteristic described in connection with the embodiment is
included in at least one embodiment of the present invention. Thus,
the appearances of the phrases "in one embodiment" or "in an
embodiment" in various places throughout this specification are not
necessarily all referring to the same embodiment. Furthermore, the
particular features, structures, or characteristics may be combined
in any suitable manner in one or more embodiments.
[0077] Certain embodiments relate to the unexpected discovery that
phosphate absorption from the intestine in subjects with elevated
phosphate serum levels may be limited, and preferably substantially
prevented, through the use of NHE3-binding and/or NHE3-modulating
agents to inhibit the intestinal transport system which mediates
phosphate uptake in the intestine. It has also been unexpectedly
discovered that such NHE3-binding and/or NHE3-modulating agents can
inhibit the renal transport system which mediates phosphate uptake
in the kidneys.
[0078] In some aspects, inhibition of phosphate uptake in the
gastrointestinal tract may be achieved by the administration of
certain compounds, and/or pharmaceutical compositions comprising
them, which may advantageously be designed such that little, or
substantially none, of the compound is absorbed into the blood
stream (that is, it is designed to be non-systemic or substantially
non-systemic). In this regard, the compounds have features that
give rise to little or substantially no systemic availability upon
enteral administration, including oral administration. In other
words, the compounds are not absorbed into the bloodstream at
meaningful levels and therefore have no activity there, but instead
have their activity localized substantially within the GI
tract.
[0079] Therefore, in certain illustrative embodiments as further
described herein, the compounds of the invention generally require
a combination of structural and/or functional features relating or
contributing to their activity in the GI tract and/or their
substantial non-systemic bioavailability. Such features may
include, for example, one or more of (i) specific tPSA and/or MW
values (e.g., at least about 190 .ANG..sup.2 and/or at least about
736 Daltons, respectively), (ii) specific levels of fecal recovery
of the compound and/or its metabolites after administration (e.g.,
greater than 50% at 72 hours); (iii) specific numbers of NH and/or
OH and/or potentially hydrogen bond donor moieties (e.g., greater
than about five); (iv) specific numbers of rotatable bonds (e.g.,
greater than about five); (iv) specific permeability features
(e.g., P.sub.app less than about 100.times.10.sup.-6 cm/s); and/or
any of a number of other features and characteristics as described
herein.
[0080] The substantially non-systemic compounds described herein
offer numerous advantages in the treatment of GI tract and other
disorders. For instance, the compounds are active on the phosphate
transporter apically located in the intestine and essentially do
not reach other phosphate transporters expressed in other tissues
and organs. Because NHE3 is expressed on cells many systemic
tissues or organs, the use of NHE3-binding or modulating agents can
raise concerns about systemic effects, whether on-target or
off-target. These particular compounds do not give rise to such
concerns because of their limited systemic availability.
[0081] As noted above, certain embodiments relate to the discovery
that phosphate absorption from the glomerular filtrate within the
kidneys of patients with elevated phosphate serum levels may be
limited, and preferably substantially prevented, through inhibition
of the renal tubule transport system which mediates phosphate
uptake in the kidneys. In some aspects, inhibition of phosphate
uptake in the kidneys may be achieved by the administration of an
otherwise substantially systemically non-bioavailable compound
described herein, by a route that optionally excludes enteral or
enteric administration, that is, by a route that optionally
excludes administration via the gastrointestinal tract.
Non-limiting examples include parenteral administration such as
intravenous, intra-arterial, intramuscular, and subcutaneous
administration, among others described herein and known in the
art.
[0082] In some aspects, inhibition of phosphate uptake in the
kidneys may be achieved by the administration of certain compounds,
and/or pharmaceutical compositions comprising them, which may
advantageously be designed such that most of the compound is
absorbed into the blood stream (that is, it is designed to be
systemic or substantially systemic). In this regard, the compounds
have features that give rise to systemic availability, including
oral availability. In other words, the compounds are absorbed into
the bloodstream at meaningful levels and therefore have most if not
all of their activity systemically, for example, within organs such
as the kidney, relative to having their activity localized
substantially within the GI tract. Therefore, in certain
embodiments, particularly for targeting systemic tissues via oral
or other form of enteral administration, the compounds described
herein may have a combination of structural and/or functional
features relating or contributing to their substantial systemic
bioavailability. Functional features include, for example, wherein
the compound is substantially permeable to the epithelium of the
gastrointestinal tract, including the mouth, esophagus, stomach,
upper intestine, lower intestine, etc.
[0083] As further detailed below, phosphate absorption in the upper
intestine is mediated, at least in part, by a carrier-mediated
mechanism which couples the absorption of phosphate to that of
sodium. Renal phosphate transport is mediated, at least in part, by
the activity of the sodium-dependent phosphate transporters, Npt2a,
Npt2c, and PiT-2, present within the apical brush border membrane
of the proximal tubule. Accordingly, inhibition of intestinal or
renal phosphate transport will reduce body phosphorus overload.
[0084] In patients with advanced kidney disease (e.g. stage 4 and
5), the body phosphorus overload manifests itself by serum
phosphate concentration above normal levels, i.e.,
hyperphosphatemia. Hyperphosphatemia is directly related to
mortality and morbidity. Inhibition of intestinal or renal
phosphate transport will reduce serum phosphate concentration and
therefore improve outcome in those patients. In stage 2 and 3
chronic kidney disease patients, the body phosphorus overload does
not necessarily lead to hyperphosphatemia, i.e., patients remain
normophosphatemic, but there is a need to reduce body phosphorus
overload even at those early stages to avoid associated bone and
vascular disorders, and ultimately improve mortality rate.
[0085] Inhibition of intestinal phosphate transport will be
particularly advantageous in patients that have a disease that is
treatable by inhibiting the uptake of phosphate from the
intestines. Likewise, inhibition of phosphate absorption from the
glomerular filtrate within the kidneys would also be advantageous
for treating or preventing chronic renal failure and other renal
disease conditions. Furthermore, inhibition of phosphate transport
may slow the progression of renal failure and reduce the risk of
cardiovascular events, among other diseases or conditions
associated with the need for phosphate lowering.
I. Compounds that Inhibit Phosphate Transport
[0086] Embodiments of the present invention relate generally to the
discovery that NHE3-binding and/or NHE3-modulating compounds
inhibit transport or uptake of phosphate ions (Pi) in tissues such
as the gastrointestinal tract and/or the kidneys. A compound's Pi
transport inhibitory activity in a given tissue will depend
generally, for example, on the systemic bioavailability or systemic
non-bioavailability of the compound, the route of administration,
or any combination thereof.
[0087] Accordingly, embodiments of the present invention include
compounds that bind to and/or modulate NHE3 (e.g., NHE inhibitors)
and are substantially active to inhibit transport or uptake of Pi,
for instance, in a human subject, an animal model, and/or a
cell-based or biochemical assay.
[0088] In some embodiments, a compound binds to NHE3. In these and
related embodiments, a compound is said to "bind" or "specifically
bind" to an NHE3 protein if it reacts at a detectable level with
the protein, and optionally does not react detectably in a
statistically significant manner with unrelated proteins under
similar conditions In certain illustrative embodiments, a compound
may have a binding "affinity" (e.g., as measured by the
dissociation constant, or K.sub.d) for an NHE3 protein of about or
less than about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15,
16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 40, 50,
60, 70, 80, 90, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000
nM.
[0089] In some embodiments, one or more of the compounds described
herein, when administered either alone or in combination with one
or more additional pharmaceutically active compounds or agents to a
subject in need thereof, or measured in an animal model or
cell-based assay, may have an IC.sub.50 for inhibiting Pi transport
or uptake of about or less than about 1, 2, 3, 4, 5, 6, 7, 8, 9,
10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26,
27, 28, 29, 30, 40, 50, 60, 70, 80, 90, 100, 200, 300, 400, 500,
600, 700, 800, 900, 1000 nM. In certain embodiments, one or more of
the compounds detailed herein, when administered either alone or in
combination with one or more additional pharmaceutically active
compounds or agents to a subject in need thereof, or measured in an
animal model or cell-based assay, may have a pIC.sub.50 for
inhibiting Pi transport or uptake of about or greater than about
6.0, 6.05, 6.1, 6.15, 6.2, 6.25, 6.3, 6.35, 6.4, 6.45, 6.5, 6.55,
6.6, 6.65, 6.7, 6.75, 6.8, 6.85, 6.9, 6.95, 7.0, 7.05, 7.1, 7.15,
7.2, 7.25, 7.3, 7.35, 7.4, 7.45, 7.5, 7.55, 7.6, 7.65, 7.7, 7.75,
7.8, 7.85, 7.9, 7.95, 8.0, 8.05, 8.1, 8.15, 8.2, 8.25, 8.3, 8.35,
8.4, 8.45, 8.5, 8.55, 8.6, 8.65, 8.7, 8.75, 8.8, 8.85, 8.9, 8.95,
or 9.0.
[0090] As used herein, the IC.sub.50 is defined as the quantitative
measure indicating the concentration of a compound where 50% of its
maximal inhibitory effect is observed, for example, in a human
subject, an animal model, and/or a cell-based or biochemical assay.
The pIC.sub.50 refers to the inverse logarithm of the IC.sub.50 (or
pIC.sub.50=-log (IC.sub.50) (see Selvaraj et al., Current Trends in
Biotechnology and Pharmacy. 5:1104-1109, 2011). Assays for
measuring the activity of inhibitors of phosphate transport or
uptake are described in the accompanying Examples.
[0091] For inhibiting transport or uptake of Pi in the
gastrointestinal tract, and treatment of related conditions in a
subject in need of phosphate lowering, embodiments of the present
invention will generally employ substantially systemically
non-bioavailable compounds. Such compounds are preferably
formulated or suitable for enteral administration, including oral
administration. Examples of substantially systemically
non-bioavailable compounds and their related features are provided
elsewhere herein. In these and related embodiments, administration
of the compound to a subject in need thereof reduces any one or
more of serum phosphate concentrations or levels, dietary
phosphorus, and/or urinary phosphate concentrations or levels. In
some embodiments, serum phosphate concentrations or levels in a
hyperphosphatemic subject are reduced to about or less than about
150%, 145%, 140%, 135%, 130%, 125%, 120%, 115%, 110%, 105%, or 100%
(normalized) of the normal serum phosphate levels (of a healthy
subject, e.g., 2.5-4.5 mg/dL or 0.81-1.45 mmol/L for a human
adult). In some embodiments, uptake of dietary phosphorous is
reduced by about or at least about 5%, 10%, 20%, 30%, 40%, 50%,
60%, 70%, 80% or more relative to an untreated state. In some
embodiments, urinary phosphate concentrations or levels are reduced
by about or at least about 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%,
80%, 90%, 100% or more, preferably about 20%, 30%, 40%, 50%, or
60%, relative to an untreated state. In some embodiments,
administration of the compound to a subject in need thereof
increases phosphate levels in fecal excretion by at least about 5%,
10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%, 200% or more
relative to an untreated state.
[0092] For inhibiting transport or uptake of Pi in the kidneys, and
treatment of related conditions in a subject in need of phosphate
lowering, embodiments of the present invention will generally
employ substantially systemically bioavailable compounds,
optionally by any route of administration, or the substantially
systemically non-bioavailable compounds described herein,
preferably by a route of administration that excludes enteral
administration. In these and related embodiments, administration of
a compound reduces serum phosphate concentrations or levels in a
hyperphosphatemic subject to about or less than about 150%, 145%,
140%, 135%, 130%, 125%, 120%, 115%, 110%, 105%, or 100%
(normalized) of the normal serum phosphate levels (of a healthy
subject, e.g., 2.5-4.5 mg/dL or 0.81-1.45 mmol/L for a human
adult). In some embodiments, administration of a compound to a
subject in need thereof increases urinary phosphate concentrations
or levels by at least about 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%,
80%, 90%, 100% or more relative to an untreated state.
[0093] In certain embodiments, the NHE3-binding compounds of the
present invention are further characterized by their activity
towards NHE3-mediated antiport of sodium and hydrogen ions. For
instance, certain compounds are substantially active to inhibit
NHE3-mediated antiport of sodium ions and hydrogen ions. Such
"dual-active" compounds can thus be used to inhibit both phosphate
and sodium transport or uptake in the gastrointestinal tract and/or
in the kidneys. In other embodiments, the compounds are
substantially inactive to inhibit NHE3-mediated antiport of sodium
ions and hydrogen ions. Such "mono-active" compounds can be used to
inhibit phosphate uptake in the gastrointestinal tract and/or in
the kidneys without significantly modulating sodium transport or
uptake in those or other tissues.
[0094] Without wishing to be bound by any one theory, it is
believed that "persistent" NHE3 inhibitor compounds (e.g.,
compounds that bind to NHE3 and inhibit NHE3-mediated antiport of
sodium and hydrogen ions under both "prompt" conditions and
"persistent" conditions) are substantially active in tissues to
inhibit both transport of Pi and NHE3-mediated antiport of sodium
and hydrogen ions. In contrast, it is believed that non-persistent
NHE3 ligands (e.g., compounds that bind to or otherwise interact
with NHE3 and might inhibit NHE3-mediated antiport of sodium and
hydrogen ions under "prompt" conditions but do not substantially
inhibit the same under "persistent" conditions) are active in
tissues to inhibit transport of Pi but are not substantially active
in tissues to inhibit NHE3-mediated antiport of sodium and hydrogen
ions. Certain characteristics of these compounds are described
below.
[0095] A. Dual-Active Compounds
[0096] Certain embodiments relate to NHE3-binding and/or
NHE3-modulating compounds that inhibit both the transport of
phosphate ions (Pi) and the NHE3-mediated antiport of sodium and
hydrogen ions. These and related embodiments include, for example,
compounds that are substantially active in the gastrointestinal
tract and/or kidneys to inhibit Pi transport and NHE3-mediated
antiport of sodium and hydrogen ions therein upon administration to
a subject in need thereof. In particular embodiments, the compounds
are substantially active on the apical side of the epithelium of
the gastrointestinal tract (e.g., upon enteral administration) to
inhibit NHE3-mediated antiport of sodium ions and hydrogen ions.
Also included are compounds that are substantially active in the
large intestine (e.g., cecum, ascending colon, transverse colon,
descending colon, sigmoid colon) to inhibit NHE3-mediated antiport
of sodium and hydrogen ions therein upon administration to the
subject in need thereof.
[0097] In some aspects, the dual-active compounds are characterized
by their "persistence" towards binding to NHE3 and inhibiting
NHE3-mediated antiport of sodium and hydrogen ions, i.e., their
"persistent inhibition" of NHE-mediated antiport of sodium and
hydrogen ions. In particular aspects, persistent inhibition is
characterized by the time-dependent inhibitory activity of the
compound in an in vitro inhibition assay of NHE3-mediated antiport
of sodium and hydrogen ions, for instance, as measured under
"persistent" conditions optionally relative to "prompt" conditions
(see, e.g., PNAS USA. (1984) 81(23): 7436-7440; and Examples
1-2).
[0098] Persistent conditions include, for instance, where a test
compound is pre-incubated with cells, e.g., for about 10, 20, 30,
40, 50, 60, 80, 100, 120 minutes or more, and washed-out prior to
lowering intracellular pH and testing for NHE3-mediated recovery of
neutral intracellular pH. Post-incubation washout can be performed,
for example, about 10, 20, 30, 40, 50, 60, 80, 100, 120 minutes or
more before lowering intracellular pH and testing for NHE3-mediated
recovery of neutral intracellular pH. In some persistent
conditions, a test compound is pre-incubated with cells for a
desired time and then washed-out of the cell medium, a buffer is
added to lower intracellular pH (e.g., incubated for about 10, 20,
30, 40, 50, or 60 minutes or more), and NHE3-mediated recovery of
neutral intracellular pH is initiated by addition of an appropriate
buffer without any test compound.
[0099] Prompt conditions include, for example, where a test
compound is incubated with cells during testing for NHE3-mediated
recovery of neutral intracellular pH, i.e., the compound is not
washed-out before or during initiating recovery of intracellular
pH. Under certain prompt conditions, a buffer is added to lower
intracellular pH (e.g., incubated for about 10, 20, 30, 40, 50, or
60 minutes or more), and NHE3-mediated recovery of neutral
intracellular pH is initiated by addition of an appropriate buffer
that contains the test compound. In one exemplary cell-based assay,
recovery of intracellular pH can be measured, for instance, by
monitoring the pH sensitive changes in fluorescence of a marker
normalized to the pH insensitive fluorescence of the marker.
Exemplary markers include bis(acetoxymethyl)
3,3'-(3',6'-bis(acetoxymethoxy)-5-((acetoxymethoxy)carbonyl)-3-oxo-3H-spi-
ro[isobenzofuran-1,9'-xanthene]-2',7'-diyl)dipropanoate
(BCECF).
[0100] In certain aspects, a dual-active compound is characterized
by the time-dependent inhibitory activity of the compound in an in
vitro inhibition assay of NHE3-mediated antiport of sodium and
hydrogen ions, wherein the pIC.sub.50 of the compound under prompt
conditions (pIC.sub.50promp) is substantially comparable to the
pIC.sub.50 of the compound under persistent conditions
(pIC.sub.50pers). Substantially comparable includes, for example,
where the pIC.sub.50promp and pIC.sub.50pers values are within
about 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, or 10%. In particular
aspects, the pIC.sub.50promp and the pIC.sub.50pers are about or at
least about 7.0, including about or at least about 6.5, 6.55, 6.6,
6.65, 6.7, 6.75, 6.8, 6.85, 6.9, 6.95, 7.0, 7.05, 7.1, 7.15, 7.2,
7.25, 7.3, 7.35, 7.4, 7.45, 7.5, 7.55, 7.6, 7.65, 7.7, 7.75, 7.8,
7.85, 7.9, 7.95, 8.0, 8.05, 8.1, 8.15, 8.2, 8.25, 8.3, 8.35, 8.4,
8.45, 8.5, 8.55, 8.6, 8.65, 8.7, 8.75, 8.8, 8.85, 8.9, 8.95, or
9.0.
[0101] In some aspects, the IC.sub.50 of the compound under prompt
conditions (IC.sub.50promp) is substantially comparable to the
IC.sub.50 of the compound under persistent conditions
(IC.sub.50pers). Substantially comparable includes, for example,
where the IC.sub.50promp and IC.sub.50pers values are within about
1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, or 10%. In particular aspects,
the IC.sub.50promp and the IC.sub.50pers are about or less than
about 0.3, 0.2, 0.1, 0.09, 0.08, 0.07, 0.06, 0.05, 0.04, 0.03,
0.02, 0.01, 0.009, 0.008, 0.007, 0.006, 0.005, 0.004, 0.003, 0.002,
or 0.001 .mu.M, or range from about 0.001-0.3, 0.001-0.2,
0.001-0.1, 0.001-0.05, 0.001-0.01, 0.001-0.005 .mu.M, or range from
about 0.005-0.3, 0.005-0.2, 0.005-0.1, 0.005-0.05, 0.005-0.01, or
range from about 0.01-0.3, 0.01-0.2, 0.01-0.1, or 0.01-0.05 .mu.M,
or range from about 0.1-0.3 or 0.1-0.2 .mu.M.
[0102] In some aspects, the dual-active compounds are characterized
by their relative activity towards inhibiting phosphate transport
and inhibiting NHE3-mediated antiport of sodium and hydrogen ions.
For instance, upon enteral administration to a subject in need of
phosphate lowering, certain compounds may have an EC.sub.50 for
increasing fecal output of phosphate ions (EC.sub.50P.sub.f) and an
EC.sub.50 for inhibiting NHE3-mediated antiport of sodium and
hydrogen ions (EC.sub.50Na) that is defined by the formula
EC.sub.50P.sub.f=(r)EC.sub.50Na, wherein r is about 0.6 to about
1.5, preferably about 0.7 to about 1.3, or about 0.6, 0.65, 0.7,
0.75, 0.8, 0.85, 0.9, 0.95, 1.0, 1.1, 1.2, 1.3, 1.4, or 1.5,
including all ranges in between. In some embodiments, for example,
upon enteral administration to a subject in need of phosphate
lowering, certain compounds may have an EC.sub.50 for reducing
urinary output of phosphate ions (EC.sub.50P.sub.u) and a EC.sub.50
for inhibiting NHE3-mediated antiport of sodium and hydrogen ions
(EC.sub.50Na) that is defined by the formula
EC.sub.50P.sub.u=(r)EC.sub.50Na, wherein r is about 0.6 to about
1.5, preferably about 0.7 to about 1.3, or about 0.6, 0.65, 0.7,
0.75, 0.8, 0.85, 0.9, 0.95, 1.0, 1.1, 1.2, 1.3, 1.4, or 1.5,
including all ranges in between. In some embodiments, for instance,
upon administration that achieves systemic availability (e.g.,
leads to activity in the kidneys), certain compounds may have an
EC.sub.50 for increasing urinary output of phosphate ions
(EC.sub.50P.sub.u) and an EC.sub.50 for inhibiting NHE3-mediated
antiport of sodium and hydrogen ions (EC.sub.50Na) that is defined
by the formula EC.sub.50P.sub.u=(r)EC.sub.50Na, wherein r is about
0.6 to about 1.5, preferably about 0.7 to about 1.3, or about 0.6,
0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, 1.0, 1.1, 1.2, 1.3, 1.4, or
1.5, including all ranges in between. In particular embodiments,
for example, upon administration to a subject in need of phosphate
lowering or in a cell-based assay, certain compounds may have an
EC.sub.50 for inhibiting transport of phosphate ions (EC.sub.50P)
and an EC.sub.50 for inhibiting NHE3-mediated antiport of sodium
and hydrogen ions (EC.sub.50Na) that is defined by the formula
EC.sub.50P=(r)EC.sub.50Na, wherein r is about 0.6 to about 1.5,
preferably about 0.7 to about 1.3, or about 0.6, 0.65, 0.7, 0.75,
0.8, 0.85, 0.9, 0.95, 1.0, 1.1, 1.2, 1.3, 1.4, or 1.5, including
all ranges in between.
[0103] In some embodiments, and further to its effects on Pi
levels, administration of a dual-active compound (or at a dosage
that allows dual-activity) to a subject in need thereof (e.g., via
enteral administration) increases the subject's daily fecal daily
output of sodium and/or fluid. In certain instances, the fecal
output of sodium is increased by about or at least about 5%, 10%,
20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%, 200%, 300%, 400%,
500%, 600%, 700%, 800%, 900%, 1000%, 1100%, 1200%, 1300%, 1400%,
1500%, 1600%, 1700%, 1800%, 1900%, or 2000% or more relative to an
untreated state. In some instances, the output of fluid or the
fecal water content is increased by about or at least about 5%,
10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%, 200%, 300%,
400%, 500%, 600%, 700%, 800%, 900%, 1000%, 1100%, 1200%, 1300%,
1400%, 1500%, 1600%, 1700%, 1800%, 1900%, or 2000% or more relative
to an untreated state.
[0104] B. Mono-Active Compounds
[0105] Certain embodiments relate to NHE3-binding compounds that
inhibit transport of phosphate ions (Pi) and but do not
substantially inhibit NHE3-mediated antiport of sodium and hydrogen
ions, for instance, at a given dosage. These and related
embodiments include, for example, non-persistent ligands of NHE3
that are substantially active to inhibit Pi transport but are
substantially inactive in the gastrointestinal tract and/or kidneys
to inhibit NHE3-mediated antiport of sodium and hydrogen ions
therein upon administration to a subject in need thereof. In some
embodiments, the non-persistent ligands of NHE3 are substantially
inactive in the large intestine (e.g., upon enteral administration)
to inhibit NHE3-mediated antiport of sodium and hydrogen ions
therein.
[0106] In some aspects, a non-persistent NHE3 ligand is
characterized by its maximum inhibitory activity towards
NHE3-mediated antiport of sodium and hydrogen ions, for instance,
in a cell-based assay or other in vitro assay. In one example, a
non-persistent NHE3 ligand has a maximum inhibition of
NHE3-mediated antiport of sodium and hydrogen ions of about or less
than about 50%, 40%, 30%, 35%, 20%, 15%, 10%, or 5%, wherein
maximum inhibition is characterized by the inhibitory activity of
the compound in an in vitro inhibition assay of NHE3-mediated
antiport of sodium and hydrogen ions and is relative to sodium-free
conditions. In these and related embodiments, sodium-free
conditions essentially represent zero activity for NHE3-mediated
antiport of sodium and hydrogen ions, and can thus be used to set
the value for 100% or maximum inhibition.
[0107] In some aspects, the non-persistent NHE3 ligands are
characterized by their "non-persistence" towards binding to NHE3
and inhibiting NHE3-mediated antiport of sodium and hydrogen ions,
i.e., their relative lack of or reduced "persistent inhibition" of
NHE-mediated antiport of sodium and hydrogen ions. In particular
aspects, persistent inhibition is characterized by the
time-dependent inhibitory activity of the compound in an in vitro
inhibition assay of NHE3-mediated antiport of sodium and hydrogen
ions, for instance, as measured under "persistent" conditions
optionally relative to "prompt" conditions (see, e.g., PNAS USA.
(1984) 81(23): 7436-7440; and Examples 1-2). Examples of persistent
and prompt conditions are described supra.
[0108] In certain aspects, the non-persistent NHE3 ligands are
characterized by the time-dependent inhibitory activity of the
compound in an in vitro inhibition assay of NHE3-mediated antiport
of sodium and hydrogen ions, wherein the pIC.sub.50 of the compound
under prompt conditions (pIC.sub.50promp) is greater than or
substantially greater than the pIC.sub.50 of the compound under
persistent conditions (pIC.sub.50pers). Substantially greater
includes, for example, where the pIC.sub.50promp is greater than
the pIC.sub.50pers by about or at least about 10%, 20%, 30%, 40%,
50%, 60%, 70%, 80%, 90%, 100%, 200% or more. In particular aspects,
the pIC.sub.50promp is about or at least about 7.0, including about
or at least about 6.5, 6.55, 6.6, 6.65, 6.7, 6.75, 6.8, 6.85, 6.9,
6.95, 7.0, 7.05, 7.1, 7.15, 7.2, 7.25, 7.3, 7.35, 7.4, 7.45, 7.5,
7.55, 7.6, 7.65, 7.7, 7.75, 7.8, 7.85, 7.9, 7.95, 8.0, 8.05, 8.1,
8.15, 8.2, 8.25, 8.3, 8.35, 8.4, 8.45, 8.5, 8.55, 8.6, 8.65, 8.7,
8.75, 8.8, 8.85, 8.9, 8.95, or 9.0, and the pIC.sub.50pers is about
or less than about 6.0, including about or less than about 6.4,
6.35, 6.3, 6.25, 6.2, 6.15, 6.1, 6.05, 6.0, 5.95, 5.9, 5.85, 5.7,
5.75, 5.6, 5.65, 5.5, 5.45, 5.4, 5.35, 5.3, 5.25, 5.2, 5.15, 5.1,
5.05, 5.0, 4.95, 4.9, 4.85, 4.8, 4.75, 4.7, 4.65, 4.6, 4.55, 4.5,
4.45, 4.4, 4.35, 4.3, 4.25, 4.2, 4.15, 4.1, 4.05, 4.0, 3.9, 3.8,
3.7, 3.6, 3.5, 3.4, 3.3, 3.2, 3.1, or 3.0.
[0109] In some aspects, the IC.sub.50 of the non-persistent NHE3
ligand under prompt conditions (IC.sub.50promp) is substantially
less than the IC.sub.50 of the compound under persistent conditions
(IC.sub.50pers). Substantially less includes, for example, where
the IC.sub.50promp is less than the IC.sub.50pers by about or at
least about 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%,
200%, 300%, 400%, 500%, or 1000%. For instance, in some aspects,
the IC.sub.50promp is about or less than about 0.3, 0.2, 0.1, 0.09,
0.08, 0.07, 0.06, 0.05, 0.04, 0.03, 0.02, 0.01, 0.009, 0.008,
0.007, 0.006, 0.005, 0.004, 0.003, 0.002, or 0.001 .mu.M, or ranges
from about 0.001-0.3, 0.001-0.2, 0.001-0.1, 0.001-0.05, 0.001-0.01,
0.001-0.005 .mu.M, or ranges from about 0.005-0.3, 0.005-0.2,
0.005-0.1, 0.005-0.05, 0.005-0.01, or ranges from about 0.01-0.3,
0.01-0.2, 0.01-0.1, or 0.01-0.05 .mu.M, or ranges from about
0.1-0.3 or 0.1-0.2 .mu.M, and the IC.sub.50pers is about or greater
than about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30, 40, 50,
60, 70, 80, 90, 100, 200, 300, 400, 500, 600, 700, 800, 900, or
1000 .mu.M or more, or ranges from about 1-10, 1-20, 1-30, 1-40,
1-50, 1-100, 1-500, 1-1000 .mu.M, or ranges from about 2-10, 2-20,
2-30, 2-40, 2-50, 2-100, 2-500, 2-1000 .mu.M, or ranges from about
5-10, 5-20, 5-30, 5-40, 5-50, 5-100, 5-500, 5-1000 .mu.M, or ranges
from about 10-20, 10-30, 10-40, 10-50, 10-100, 10-500, 10-1000
.mu.M, or ranges from about 20-30, 20-40, 20-50, 20-100, 20-500,
20-1000 .mu.M, or ranges from about 50-100, 50-500, 50-1000 .mu.M,
or ranges from about 100-500 or 100-1000 .mu.M.
[0110] In some aspects, the non-persistent NHE3 ligands are
characterized by their relative activity towards inhibiting
phosphate transport and inhibiting NHE3-mediated antiport of sodium
and hydrogen ions. For instance, upon enteral administration to a
subject in need of phosphate lowering, certain compounds may have
an EC.sub.50 for increasing fecal output of phosphate ions
(EC.sub.50P.sub.f) and an EC.sub.50 for inhibiting NHE3-mediated
antiport of sodium and hydrogen ions (EC.sub.50Na) that is defined
by the formula EC.sub.50P.sub.f=(r)EC.sub.50Na, wherein r is about
0.1 to about 0.5, or about 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35,
0.4, 0.45, 0.5, or 0.55, including all ranges in between. In some
embodiments, for example, upon enteral administration to a subject
in need of phosphate lowering, certain compounds may have an
EC.sub.50 for reducing urinary output of phosphate ions
(EC.sub.50P.sub.u) and an EC.sub.50 for inhibiting NHE3-mediated
antiport of sodium and hydrogen ions (EC.sub.50Na) that is defined
by the formula EC.sub.50P.sub.u=(r)EC.sub.50Na, wherein r is about
0.1 to about 0.5, or about 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35,
0.4, 0.45, 0.5, or 0.55, including all ranges in between. In
particular embodiments, for example, upon enteral administration to
a subject in need of phosphate lowering or in a cell-based assay,
certain compounds may have an EC.sub.50 for inhibiting transport of
phosphate ions (EC.sub.50P) and an EC.sub.50 for inhibiting
NHE3-mediated antiport of sodium and hydrogen ions (EC.sub.50Na)
that is defined by the formula EC.sub.50P=(r)EC.sub.50Na, wherein r
is about 0.05 or 0.1 to about 0.5 or 0.55 or so, or about 0.05,
0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, or 0.55, including
all ranges in between. In some embodiments, for instance, upon
administration that achieves systemic availability (e.g., leads to
significant activity in the kidneys), certain non-persistent NHE3
ligand compounds may have an EC.sub.50 for increasing urinary
output of phosphate ions (EC.sub.50P.sub.u) and an EC.sub.50 for
inhibiting NHE3-mediated antiport of sodium and hydrogen ions
(EC.sub.50Na) that is defined by the formula
EC.sub.50P.sub.u=(r)EC.sub.50Na, wherein r is about 0.1 to about
0.5, or about 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45,
0.5, or 0.55, including all ranges in between.
[0111] In certain embodiments, administration a non-persistent NHE3
ligand to a subject in need thereof (e.g., via enteral
administration) increases the ratio of phosphate/sodium in fecal
excretion by about or at least about 5%, 10%, 20%, 30%, 40%, 50%,
60%, 70%, 80%, 90%, 100%, 200% or more relative to an untreated
state. In some embodiments, administration to a subject in need
thereof (e.g., via enteral administration) increases the daily
fecal output of phosphate without substantially modulating the
stool form or water content of the feces. For instance, in these
and related embodiments, the stool form of the feces can be about
or within about 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, or
20% of the stool form of the feces relative to an untreated state.
In some aspects, the fecal form under the Bristol stool scale
(Types 1, 2, 3, 4, 5, 6, and 7; Type 1 being hard and Type 7 being
watery) can be the same or within about 1-2 units relative to an
untreated state (see, e.g., Rao et al., Neurogastroenterol Motil.
23:8-23, 2011; and Lewis and Heaton, Scand. J. Gastroenterol.
32:920-4, 1997). In specific aspects, the fecal form under the
Bristol scale is Type 3 or Type 4. In some embodiments,
administration to a rodent (e.g., rat, mouse) increases the ratio
of sodium in the small intestine (Na.sub.SI)/cecum (Na.sub.C) by at
least about 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%,
200% or more relative to an untreated state.
II. Substantially Systemically Non-Bioavailable Compounds
A. Physical and Performance Properties of Compounds Localizable to
the GI Tract
[0112] Certain of the compounds described herein are designed to be
substantially active or localized in the gastrointestinal lumen of
a human or animal subject. The term "gastrointestinal lumen" is
used interchangeably herein with the term "lumen," to refer to the
space or cavity within a gastrointestinal tract (GI tract, which
can also be referred to as the gut), delimited by the apical
membrane of GI epithelial cells of the subject. In some
embodiments, the compounds are not absorbed through the layer of
epithelial cells of the GI tract (also known as the GI epithelium).
"Gastrointestinal mucosa" refers to the layer(s) of cells
separating the gastrointestinal lumen from the rest of the body and
includes gastric and intestinal mucosa, such as the mucosa of the
small intestine. A "gastrointestinal epithelial cell" or a "gut
epithelial cell" as used herein refers to any epithelial cell on
the surface of the gastrointestinal mucosa that faces the lumen of
the gastrointestinal tract, including, for example, an epithelial
cell of the stomach, an intestinal epithelial cell, a colonic
epithelial cell, and the like.
[0113] "Substantially systemically non-bioavailable" and/or
"substantially impermeable" as used herein (as well as variations
thereof) generally refer to situations in which a statistically
significant amount, and in some embodiments essentially all of the
compound remains in the gastrointestinal lumen. For example, in
accordance with one or more embodiments of the present disclosure,
preferably at least about 60%, about 70%, about 75%, about 80%,
about 85%, about 90%, about 95%, about 96%, about 97%, about 98%,
about 99%, or even about 99.5%, of the compound remains in the
gastrointestinal lumen. In such cases, localization to the
gastrointestinal lumen refers to reducing net movement of a
compound across a gastrointestinal layer of epithelial cells, for
example, by way of both transcellular and paracellular transport,
as well as by active and/or passive transport. The compound in such
embodiments is hindered from net permeation of a layer of
gastrointestinal epithelial cells in transcellular transport, for
example, through an apical membrane of an epithelial cell of the
small intestine. The compound in these embodiments is also hindered
from net permeation through the "tight junctions" in paracellular
transport between gastrointestinal epithelial cells lining the
lumen.
[0114] In this regard it is to be noted that, in one particular
embodiment, the compound is essentially not absorbed at all by the
GI tract or gastrointestinal lumen. As used herein, the terms
"substantially impermeable" or "substantially systemically
non-bioavailable" includes embodiments wherein no detectable amount
of absorption or permeation or systemic exposure of the compound is
detected, using means generally known in the art.
[0115] In this regard it is to be further noted, however, that in
alternative embodiments "substantially impermeable" or
"substantially systemically non-bioavailable" provides or allows
for some limited absorption in the GI tract, and more particularly
the gut epithelium, to occur (e.g., some detectable amount of
absorption, such as for example at least about 0.1%, 0.5%, 1% or
more and less than about 30%, 20%, 10%, 5%, etc., the range of
absorption being for example between about 1% and 30%, or 5% and
20%, etc.); stated another way, "substantially impermeable" or
"substantially systemically non-bioavailable" may refer to
compounds that exhibit some detectable permeability to an
epithelial layer of cells in the GI tract of less than about 20% of
the administered compound (e.g., less than about 15%, about 10%, or
even about 5%, 4%, 3%, or 2%, and for example greater than about
0.5%, or 1%), but then are cleared by the liver (i.e., hepatic
extraction) and/or the kidney (i.e., renal excretion).
[0116] In this regard it is to be further noted, that in certain
embodiments, due to the substantial impermeability and/or
substantial systemic non-bioavailability of the compounds of the
present invention, greater than about 50%, 60%, 70%, 80%, 90%, or
95% of a compound of the invention is recoverable from the feces
over, for example, a 24, 36, 48, 60, 72, 84, or 96 hour period
following administration to a subject in need thereof. In this
respect, it is understood that a recovered compound can include the
sum of the parent compound and its metabolites derived from the
parent compound, e.g., by means of hydrolysis, conjugation,
reduction, oxidation, N-alkylation, glucuronidation, acetylation,
methylation, sulfation, phosphorylation, or any other modification
that adds atoms to or removes atoms from the parent compound,
wherein the metabolites are generated via the action of any enzyme
or exposure to any physiological environment including, pH,
temperature, pressure, or interactions with foodstuffs as they
exist in the digestive milieu.
[0117] Measurement of fecal recovery of compound and metabolites
can be carried out using standard methodology. For example, a
compound can be administered orally at a suitable dose (e.g., 10
mg/kg) and feces are then collected at predetermined times after
dosing (e.g., 24 hours, 36 hours, 48 hours, 60 hours, 72 hours, 96
hours). Parent compound and metabolites can be extracted with
organic solvent and analyzed quantitatively using mass
spectrometry. A mass balance analysis of the parent compound and
metabolites (including, parent=M, metabolite 1 [M+16], and
metabolite 2 [M+32]) can be used to determine the percent recovery
in the feces.
(i) Permeability
[0118] In this regard it is to be noted that, in various
embodiments, the ability of the compound to be substantially
systemically non-bioavailable is based on the compound charge,
size, and/or other physicochemical parameters (e.g., polar surface
area, number of hydrogen bond donors and/or acceptors therein,
number of freely rotatable bonds, etc.). More specifically, it is
to be noted that the absorption character of a compound can be
selected by applying principles of pharmacokinetics, for example,
by applying Lipinski's rule, also known as "the rule of five."
Although not a rule, but rather a set of guidelines, Lipinski shows
that small molecule drugs with (i) a molecular weight, (ii) a
number of hydrogen bond donors, (iii) a number of hydrogen bond
acceptors, and/or (iv) a water/octanol partition coefficient
(Moriguchi Log P), greater than a certain threshold value,
generally do not show significant systemic concentration (i.e., are
generally not absorbed to any significant degree). (See, e.g.,
Lipinski et al., Advanced Drug Delivery Reviews, 46:3-26, 2001
incorporated herein by reference.) Accordingly, substantially
systemically non-bioavailable compounds can be designed to have
molecular structures exceeding one or more of Lipinski's threshold
values. (See also Lipinski et al., Experimental and Computational
Approaches to Estimate Solubility and Permeability in Drug
Discovery and Development Settings, Adv. Drug Delivery Reviews,
46:3-26 (2001); and Lipinski, Drug-like Properties and the Causes
of Poor Solubility and Poor Permeability, J. Pharm. & Toxicol.
Methods, 44:235-249 (2000), incorporated herein by reference.).
[0119] In some embodiments, for example, a substantially
impermeable or substantially systemically non-bioavailable compound
of the present disclosure can be constructed to feature one or more
of the following characteristics: (i) a MW greater than about 500
Da, about 600 Da, about 700 Da, about 800 Da, about 900 Da, about
1000 Da, about 1200 Da, about 1300 Da, about 1400 Da, about 1500
Da, about 1600 Da, about 1800 Da, about 2000 Da, about 2500 Da,
about 3000 Da, about 4000 Da, about 5000 Da, about 7500 Da, about
10,000 Da or more (in the non-salt form of the compound); (ii) a
total number of NH and/or OH and/or other potential hydrogen bond
donors greater than about 5, about 6, about 7, about 8, about 9,
about 10, about 11, about 12, about 13, about 14, about 15, about
20 or more; (iii) a total number of O atoms and/or N atoms and/or
other potential hydrogen bond acceptors greater than about 5, about
6, about 7, about 8, about 9, about 10, about 11, about 12, about
13, about 14, about 15, about 20 or more; (iv) a Moriguchi
partition coefficient greater than about 10.sup.5 (i.e., Log P
greater than about 5, about 6, about 7, about 8, about 9, about 10
etc.), or alternatively less than about 10 (i.e., a Log P of less
than 1, or even 0); and/or (v) a total number of rotatable bonds
greater than about 5, about 10 or about 15, or more. In specific
embodiments, the compound has a Log P that is not 14 or is less
than about 14, for instance, a Log P that is in the range of about
6-7, 6-8, 6-9, 6-10, 6-11, 6-12, 6-13, 7-8, 7-9, 7-10, 7-11, 7-12,
7-13, 8-9, 8-10, 8-11, 8-12, 8-13, 9-10, 9-11, 9-12, 9-13, 10-11,
10-12, 10-13, 11-12, 11-13, or 12-13.
[0120] In addition to the parameters noted above, the molecular
polar surface area (i.e., "PSA"), which may be characterized as the
surface belonging to polar atoms, is a descriptor that has also
been shown to correlate well with passive transport through
membranes and, therefore, allows prediction of transport properties
of drugs. It has been successfully applied for the prediction of
intestinal absorption and Caco2 cell monolayer penetration. For
exemplary Caco2 cell monolayer penetration test details, see for
example the description of the Caco2 Model provided in U.S. Pat.
No. 6,737,423, incorporated by reference, particularly the text
describing the Caco2 Model, which may be applied for example to the
evaluation or testing of the compounds of the present invention.
PSA is expressed in .ANG.2 (squared angstroms) and is computed from
a three-dimensional molecular representation. A fast calculation
method is also available (see, e.g., Ertl et al., Journal of
Medicinal Chemistry, 2000, 43, 3714-3717, the entire contents of
which are incorporated herein by reference for all relevant and
consistent purposes) using a desktop computer and commercially
available chemical graphic tools packages, such as ChemDraw. The
term "topological PSA" (tPSA) has been coined for this
fast-calculation method. tPSA is well correlated with human
absorption data with common drugs (see Table 1, from Ertl et al., J
Med. Chem., 2000, 43:3714-3717):
TABLE-US-00001 TABLE 1 name % FA.sup.a TPSA.sup.b metoprolol 102
50.7 nordiazepam 99 41.5 diazepam 97 32.7 oxprenolol 97 50.7
phenazone 97 26.9 oxazepam 97 51.7 alprenolol 96 41.9 practolol 95
70.6 pindolol 92 57.3 ciprofloxacin 69 74.6 metolazone 64 92.5
tranexamic acid 55 63.3 atenolol 54 84.6 sulpiride 36 101.7
mannitol 26 121.4 foscarnet 17 94.8 sulfasalazine 12 141.3
olsalazine 2.3 139.8 lactulose 0.6 197.4 raffinose 0.3 268.7
[0121] Accordingly, in some embodiments, the compounds of the
present disclosure may be constructed to exhibit a tPSA value
greater than about 100 .ANG..sup.2, about 116 .ANG..sup.2, about
120 .ANG..sup.2, about 130 .ANG..sup.2, or about 140 .ANG..sup.2,
and in some instances about 150 .ANG..sup.2, about 160 .ANG..sup.2,
about 170 .ANG..sup.2, about 180 .ANG..sup.2, about 190
.ANG..sup.2, about 200 .ANG..sup.2, about 225 .ANG..sup.2, about
250 .ANG..sup.2, about 270 .ANG..sup.2, about 300 .ANG..sup.2,
about 350 .ANG..sup.2, about 400 .ANG..sup.2, about 450
.ANG..sup.2, about 500 .ANG..sup.2, about 750 .ANG..sup.2, or even
about 1000 .ANG..sup.2, or in the range of about 100-120
.ANG..sup.2, 100-130 .ANG..sup.2, 100-140 .ANG..sup.2, 100-150
.ANG..sup.2, 100-160 .ANG..sup.2, 100-170 .ANG..sup.2, 100-170
.ANG..sup.2, 100-190 .ANG..sup.2, 100-200 .ANG..sup.2, 100-225
.ANG..sup.2, 100-250 .ANG..sup.2, 100-300 .ANG..sup.2, 100-400
.ANG..sup.2, 100-500 .ANG..sup.2, 100-750 .ANG..sup.2, 100-1000
.ANG..sup.2, 116-120 .ANG..sup.2, 116-130 .ANG..sup.2, 116-140
.ANG..sup.2, 116-150 .ANG..sup.2, 116-160 .ANG..sup.2, 116-170
.ANG..sup.2, 116-170 .ANG..sup.2, 116-190 .ANG..sup.2, 116-200
.ANG..sup.2, 116-225 .ANG..sup.2, 116-250 .ANG..sup.2, 116-300
.ANG..sup.2, 116-400 .ANG..sup.2, 116-500 .ANG..sup.2, 116-750
.ANG..sup.2, 116-1000 .ANG..sup.2, 120-130 .ANG..sup.2, 120-140
.ANG..sup.2, 120-150 .ANG..sup.2, 120-160 .ANG..sup.2, 120-170
.ANG..sup.2, 120-170 .ANG..sup.2, 120-190 .ANG..sup.2, 120-200
.ANG..sup.2, 120-225 .ANG..sup.2, 120-250 .ANG..sup.2, 120-300
.ANG..sup.2, 120-400 .ANG..sup.2, 120-500 .ANG..sup.2, 120-750
.ANG..sup.2, 120-1000 .ANG..sup.2, 130-140 .ANG..sup.2, 130-150
.ANG..sup.2, 130-160 .ANG..sup.2, 130-170 .ANG..sup.2, 130-170
.ANG..sup.2, 130-190 .ANG..sup.2, 130-200 .ANG..sup.2, 130-225
.ANG..sup.2, 130-250 .ANG..sup.2, 130-300 .ANG..sup.2, 130-400
.ANG..sup.2, 130-500 .ANG..sup.2, 130-750 .ANG..sup.2, 130-1000
.ANG..sup.2, 140-150 .ANG..sup.2, 140-160 .ANG..sup.2, 140-170
.ANG..sup.2, 140-170 .ANG..sup.2, 140-190 .ANG..sup.2, 140-200
.ANG..sup.2, 140-225 .ANG..sup.2, 140-250 .ANG..sup.2, 140-300
.ANG..sup.2, 140-400 .ANG..sup.2, 140-500 .ANG..sup.2, 140-750
.ANG..sup.2, 140-1000 .ANG..sup.2, 150-160 .ANG..sup.2, 150-170
.ANG..sup.2, 150-170 .ANG..sup.2, 150-190 .ANG..sup.2, 150-200
.ANG..sup.2, 150-225 .ANG..sup.2, or 150-250 .ANG..sup.2, 150-300
.ANG..sup.2, 150-400 .ANG..sup.2, 150-500 .ANG..sup.2, 150-750
.ANG..sup.2, 150-1000 .ANG..sup.2, 200-250 .ANG..sup.2, 200-300
.ANG..sup.2, 200-400 .ANG..sup.2, 200-500 .ANG..sup.2, 200-750
.ANG..sup.2, 200-1000 .ANG..sup.2, 250-250 .ANG..sup.2, 250-300
.ANG..sup.2, 250-400 .ANG..sup.2, 20-500 .ANG..sup.2, 250-750
.ANG..sup.2, or 250-1000 .ANG..sup.2, such that the compounds are
substantially impermeable (e.g., cell impermeable) or substantially
systemically non-bioavailable (as defined elsewhere herein).
[0122] Because there are exceptions to Lipinski's "rule," or the
tPSA model, the permeability properties of the compounds of the
present disclosure may be screened experimentally. The permeability
coefficient can be determined by methods known to those of skill in
the art, including for example by Caco-2 cell permeability assay
and/or using an artificial membrane as a model of a
gastrointestinal epithelial cell. A synthetic membrane impregnated
with, for example, lecithin and/or dodecane to mimic the net
permeability characteristics of a gastrointestinal mucosa may be
utilized as a model of a gastrointestinal mucosa. The membrane can
be used to separate a compartment containing the compound of the
present disclosure from a compartment where the rate of permeation
will be monitored. Also, parallel artificial membrane permeability
assays (PAMPA) can be performed. Such in vitro measurements can
reasonably indicate actual permeability in vivo (see Wohnsland et
al., J Med. Chem. 44:923-930, 2001; Schmidt et al., Millipore Corp.
Application Note, 2002, n AN1725EN00, and n AN1728EN00,
incorporated herein by reference).
[0123] Accordingly, in some embodiments, the compounds utilized in
the methods of the present disclosure may have a permeability
coefficient, P.sub.app, of less than about 100.times.10.sup.-6
cm/s, or less than about 10.times.10.sup.-6 cm/s, or less than
about 1.times.10.sup.-6 cm/s, or less than about
0.1.times.10.sup.-6 cm/s, when measured using means known in the
art (such as for example the permeability experiment described in
Wohnsland et al., 2001, supra).
[0124] As previously noted, in accordance with the present
disclosure, compounds may be modified to hinder their net
absorption through a layer of gut epithelial cells, rendering them
substantially systemically non-bioavailable. In some particular
embodiments, the compounds of the present disclosure comprise a
compound that is linked, coupled or otherwise attached to a
non-absorbable moiety, which may be an oligomer moiety, a polymer
moiety, a hydrophobic moiety, a hydrophilic moiety, and/or a
charged moiety, which renders the overall compound substantially
impermeable or substantially systemically non-bioavailable. In some
preferred embodiments, the compound is coupled to a multimer or
polymer portion or moiety, such that the resulting molecule is
substantially impermeable or substantially systemically
non-bioavailable. The multimer or polymer portion or moiety may be
of a molecular weight greater than about 500 Daltons (Da), about
1000 Da, about 2500 Da, about 5000 Da, about 10,000 Da or more, and
in particular may have a molecular weight in the range of about
1000 Daltons (Da) to about 500,000 Da, preferably in the range of
about 5000 to about 200,000 Da, and more preferably may have a
molecular weight that is sufficiently high to essentially preclude
any net absorption through a layer of gut epithelial cells of the
compound. In these or other particular embodiments, the compound is
modified to substantially hinder its net absorption through a layer
of gut epithelial cells.
(ii) C.sub.max and IC.sub.50 or EC.sub.50
[0125] In some embodiments, the substantially systemically
non-bioavailable compounds detailed herein, when administered
(e.g., enterally) either alone or in combination with one or more
additional pharmaceutically active compounds or agents to a subject
in need thereof, exhibit a maximum concentration detected in the
serum, defined as C.sub.max, that is about the same as or less than
the phosphate ion (Pi) transport or uptake inhibitory concentration
IC.sub.50 of the compound. In some embodiments, for instance, the
C.sub.max is about or at least about 5%, 10%, 20%, 30%, 40%, 50%,
60%, 70%, 80%, 90%, or 100% less than the IC.sub.50 for inhibiting
Pi transport or uptake. In some embodiments, the C.sub.max is about
0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.2,
0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9.times. (0.9 times) the IC.sub.50
for inhibiting Pi transport or uptake.
[0126] In certain embodiments, one or more of the substantially
systemically non-bioavailable compounds detailed herein, when
administered (e.g., enterally) to a subject in need thereof, may
have a ratio of C.sub.max:IC.sub.50 (for inhibiting Pi transport or
update), wherein C.sub.max and IC.sub.50 are expressed in terms of
the same units, of at about or less than about 0.01, 0.02, 0.03,
0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6,
0.7, 0.8, 0.9, or 1.0, or a range in between about 0.01-1.0,
0.01-0.9, 0.01-0.8, 0.01-0.7, 0.01-0.6, 0.01-0.5, 0.01-0.4,
0.01-0.3, 0.01-0.2, or 0.01-0.1, or a range in between about
0.1-1.0, 0.1-0.9, 0.1-0.8, 0.1-0.7, 0.1-0.6, 0.1-0.5, 0.1-0.4,
0.1-0.3, or 0.1-0.2.
[0127] In some embodiments, the substantially systemically
non-bioavailable compounds detailed herein, when administered
(e.g., enterally) either alone or in combination with one or more
additional pharmaceutically active compounds or agents to a subject
in need thereof, exhibit a maximum concentration detected in the
serum, defined as C.sub.max, that is about the same as or less than
EC.sub.50 of the compound for increasing fecal output of phosphate,
where fecal output is increased by about or at least about 5%, 10%,
20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, or 100%. In some
embodiments, for instance, the C.sub.max is about or at least about
5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, or 100% less than
the EC.sub.50 for increasing fecal output of phosphate. In some
embodiments, the C.sub.max is about 0.01, 0.02, 0.03, 0.04, 0.05,
0.06, 0.07, 0.08, 0.09, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8,
0.9.times. (0.9 times) the EC.sub.50 for increasing fecal output of
phosphate.
[0128] In some embodiments, one or more of the substantially
systemically non-bioavailable compounds detailed herein, when
administered (e.g., enterally) either alone or in combination with
one or more additional pharmaceutically active compounds or agents
to a subject in need thereof, or measured in an animal model or
cell-based assay, may have an EC.sub.50 for increasing fecal output
of phosphate of about or less than about 10 .mu.M, 9 .mu.M, 8
.mu.M, 7 .mu.M, 7.5 .mu.M, 6 .mu.M, 5 .mu.M, 4 .mu.M, 3 .mu.M, 2.5
.mu.M, 2 .mu.M, 1 .mu.M, 0.5 .mu.M, 0.1 .mu.M, 0.05 .mu.M, or 0.01
.mu.M, or less, the IC.sub.50 being, for example, within the range
of about 0.01 .mu.M to about 10 .mu.M, or about 0.01 .mu.M to about
7.5 .mu.M, or about 0.01 .mu.M to about 5 .mu.M, or about 0.01
.mu.M to about 2.5 .mu.M, or about 0.01 .mu.M to about 1.0, or
about 0.1 .mu.M to about 10 .mu.M, or about 0.1 .mu.M to about 7.5
.mu.M, or about 0.1 .mu.M to about 5 .mu.M, or about 0.1 .mu.M to
about 2.5 .mu.M, or about 0.1 .mu.M to about 1.0, or about .mu.M
0.5 .mu.M to about 10 .mu.M, or about 0.5 .mu.M to about 7.5 .mu.M,
or about 0.5 .mu.M to about 5 .mu.M, or about 0.5 .mu.M to about
2.5 .mu.M, or about 0.5 .mu.M to about 1.0 .mu.M.
[0129] In particular embodiments, the substantially systemically
non-bioavailable compounds detailed herein, when administered
(e.g., enterally) either alone or in combination with one or more
additional pharmaceutically active compounds or agents to a subject
in need thereof, exhibit a maximum concentration detected in the
serum, defined as C.sub.max, that is about the same as or less than
EC.sub.50 of the compound for reducing urinary output of phosphate,
where urinary output is reduced by about or at least about 5%, 10%,
20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, or 100%. In some
embodiments, for instance, the C.sub.max is about or at least about
5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, or 100% less than
the EC.sub.50 for reducing urinary output of phosphate. In some
embodiments, the C.sub.max is about 0.01, 0.02, 0.03, 0.04, 0.05,
0.06, 0.07, 0.08, 0.09, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8,
0.9.times. (0.9 times) the EC.sub.50 for reducing urinary output of
phosphate.
[0130] In some embodiments, one or more of the substantially
systemically non-bioavailable compounds detailed herein, when
administered (e.g., enterally) either alone or in combination with
one or more additional pharmaceutically active compounds or agents
to a subject in need thereof, or measured in an animal model or
cell-based assay, may have an EC.sub.50 for reducing urinary output
of phosphate of about or less than about 10 .mu.M, 9 .mu.M, 8
.mu.M, 7 .mu.M, 7.5 .mu.M, 6 .mu.M, 5 .mu.M, 4 .mu.M, 3 .mu.M, 2.5
.mu.M, 2 .mu.M, 1 .mu.M, 0.5 .mu.M, 0.1 .mu.M, 0.05 .mu.M, or 0.01
.mu.M, or less, the IC.sub.50 being, for example, within the range
of about 0.01 .mu.M to about 10 .mu.M, or about 0.01 .mu.M to about
7.5 .mu.M, or about 0.01 .mu.M to about 5 .mu.M, or about 0.01
.mu.M to about 2.5 .mu.M, or about 0.01 .mu.M to about 1.0, or
about 0.1 .mu.M to about 10 .mu.M, or about 0.1 .mu.M to about 7.5
.mu.M, or about 0.1 .mu.M to about 5 .mu.M, or about 0.1 .mu.M to
about 2.5 .mu.M, or about 0.1 .mu.M to about 1.0, or about .mu.M
0.5 .mu.M to about 10 .mu.M, or about 0.5 .mu.M to about 7.5 .mu.M,
or about 0.5 .mu.M to about 5 .mu.M, or about 0.5 .mu.M to about
2.5 .mu.M, or about 0.5 .mu.M to about 1.0 .mu.M.
[0131] In certain embodiments, one or more of the substantially
systemically non-bioavailable compounds detailed herein, when
administered (e.g., enterally) to a subject in need thereof, may
have a ratio of C.sub.max:EC.sub.50 (e.g., for increasing fecal
output of phosphate, for decreasing urinary output of phosphate),
wherein C.sub.max and EC.sub.50 are expressed in terms of the same
units, of at about or less than about 0.01, 0.02, 0.03, 0.04, 0.05,
0.06, 0.07, 0.08, 0.09, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8,
0.9, or 1.0, or a range in between about 0.01-1.0, 0.01-0.9,
0.01-0.8, 0.01-0.7, 0.01-0.6, 0.01-0.5, 0.01-0.4, 0.01-0.3,
0.01-0.2, or 0.01-0.1, or a range in between about 0.1-1.0,
0.1-0.9, 0.1-0.8, 0.1-0.7, 0.1-0.6, 0.1-0.5, 0.1-0.4, 0.1-0.3, or
0.1-0.2.
[0132] Additionally, or alternatively, one or more of the
substantially systemically non-bioavailable compounds detailed
herein, when administered (e.g., enterally) either alone or in
combination with one or more additional pharmaceutically active
compounds or agents to a subject in need thereof, may have a
C.sub.max of about or less than about 10 ng/ml, about 7.5 ng/ml,
about 5 ng/ml, about 2.5 ng/ml, about 1 ng/ml, or about 0.5 ng/ml,
the C.sub.max being for example within the range of about 1 ng/ml
to about 10 ng/ml, or about 2.5 ng/ml to about 7.5 ng/ml.
B. Exemplary Structures
[0133] Generally speaking, the present disclosure encompasses
essentially any small molecule, which may be monovalent or
polyvalent, that binds to and/or modulates NHE3 and has activity as
a phosphate transport inhibitor, including small molecules that are
substantially impermeable or substantially systemically
non-bioavailable in the gastrointestinal tract, including known
NHE-binding compounds that may be modified or functionalized in
accordance with the present disclosure to alter the physicochemical
properties thereof so as to render the overall compound
substantially active in the GI tract.
[0134] Accordingly, the compounds of the present disclosure may be
generally represented by Formula (I):
NHE-Z (1)
[0135] wherein: (i) NHE represents a NHE-binding small molecule,
and (ii) Z represents a moiety having at least one site thereon for
attachment to an NHE-binding small molecule, the resulting NHE-Z
molecule possessing overall physicochemical properties that render
it substantially impermeable or substantially systemically
non-bioavailable. The NHE-binding small molecule generally
comprises a heteroatom-containing moiety and a cyclic or
heterocyclic scaffold or support moiety bound directly or
indirectly thereto. In particular, examination of the structures of
small molecules reported to-date to be NHE-binders or inhibitors
suggest, as further illustrated herein below, that most comprise a
cyclic or heterocyclic support or scaffold bound directly or
indirectly (by, for example, an acyl moiety or a hydrocarbyl or
heterohydrocarbyl moiety, such as an alkyl, an alkenyl, a
heteroalkyl or a heteroalkenyl moiety) to a heteroatom-containing
moiety that is capable of acting as a sodium atom or sodium ion
mimic, which is typically selected from a substituted guanidinyl
moiety and a substituted heterocyclic moiety (e.g., a
nitrogen-containing heterocyclic moiety). Optionally, the
heteroatom-containing moiety may be fused with the scaffold or
support moiety to form a fused, bicyclic structure, and/or it may
be capable of forming a positive charge at a physiological pH.
[0136] In this regard it is to be noted that, while the
heteroatom-containing moiety that is capable of acting as a sodium
atom or ion mimic may optionally form a positive charge, this
should not be understood or interpreted to require that the overall
compound have a net positive charge, or only a single positively
charged moiety therein. Rather, in various embodiments, the
compound may have no charged moieties, or it may have multiple
charged moieties therein (which may have positive charges, negative
charges, or a combination thereof, the compound for example being a
zwitterion). Additionally, it is to be understood that the overall
compound may have a net neutral charge, a net positive charge
(e.g., +1, +2, +3, etc.), or a net negative charge (e.g., -1, -2,
-3, etc.).
[0137] The Z moiety may be bound to essentially any position on, or
within, the NHE small molecule, and in particular may be: (i) bound
to the scaffold or support moiety, (ii) bound to a position on, or
within, the heteroatom-containing moiety, and/or (iii) bound to a
position on, or within, a spacer moiety that links the scaffold to
the heteroatom-containing moiety, provided that the installation of
the Z moiety does not significantly adversely impact NHE-binding
activity. In one particular embodiment, Z may be in the form of an
oligomer, dendrimer or polymer bound to the NHE small molecule
(e.g., bound for example to the scaffold or the spacer moiety), or
alternatively Z may be in the form of a linker that links multiple
NHE small molecules together, and therefore that acts to increase:
(i) the overall molecular weight and/or polar surface area of the
NHE-Z molecule; and/or, (ii) the number of freely rotatable bonds
in the NHE-Z molecule; and/or, (iii) the number of hydrogen-bond
donors and/or acceptors in the NHE-Z molecule; and/or, (iv) the Log
P value of the NHE-Z molecule to a value of at least about 5 (or
alternatively less than 1, or even about 0), all as set forth
herein; such that the overall NHE-binding compound (i.e., the NHE-Z
compound) is substantially impermeable or substantially
systemically non-bioavailable.
[0138] The present disclosure is more particularly directed to such
a substantially impermeable or substantially systemically
non-bioavailable, NHE-binding compound, or a pharmaceutical salt
thereof, wherein the compound has the structure of Formula
(II):
##STR00027##
wherein: (i) Z, as previously defined above, is a moiety bound to
or incorporated in the NHE-binding small molecule, such that the
resulting NHE-Z molecule possesses overall physicochemical
properties that render it substantially impermeable or
substantially systemically non-bioavailable; (ii) B is the
heteroatom-containing moiety of the NHE-binding small molecule, and
in one particular embodiment is selected from a substituted
guanidinyl moiety and a substituted heterocyclic moiety, which may
optionally be fused with the Scaffold moiety to form a fused,
bicyclic structure; (iii) Scaffold is the cyclic or heterocyclic
moiety to which is bound directly or indirectly the hetero-atom
containing moiety (e.g., the substituted guanidinyl moiety or a
substituted heterocyclic moiety), B, and which is optionally
substituted with one or more additionally hydrocarbyl or
heterohydrocarbyl moieties; (iv) X is a bond or a spacer moiety
selected from a group consisting of substituted or unsubstituted
hydrocarbyl or heterohydrocarbyl moieties, and in particular
substituted or unsubstituted C.sub.1-C.sub.7 hydrocarbyl or
heterohydrocarbyl (e.g., C.sub.1-C.sub.7 alkyl, alkenyl,
heteroalkyl or heteroalkenyl), and substituted or unsubstituted,
saturated or unsaturated, cyclic or heterocyclic moieties (e.g.,
C.sub.4-C.sub.7 cyclic or heterocyclic moieties), which links B and
the Scaffold; and, (v) D and E are integers, each independently
having a value of 1, 2 or more.
[0139] In one or more particular embodiments, as further
illustrated herein below, B may be selected from a guanidinyl
moiety or a moiety that is a guanidinyl bioisostere selected from
the group consisting of substituted cyclobutenedione, substituted
imidazole, substituted thiazole, substituted oxadiazole,
substituted pyrazole, or a substituted amine. More particularly, B
may be selected from guanidinyl, acylguanidinyl,
sulfonylguanidinyl, or a guanidine bioisostere such as a
cyclobutenedione, a substituted or unsubstituted 5- or 6-member
heterocycle such as substituted or unsubstituted imidazole,
aminoimidazole, alkylimidizole, thiazole, oxadiazole, pyrazole,
alkylthioimidazole, or other functionality that may optionally
become positively charged or function as a sodium mimetic,
including amines (e.g., tertiary amines), alkylamines, and the
like, at a physiological pH. In one particularly preferred
embodiment, B is a substituted guanidinyl moiety or a substituted
heterocyclic moiety that may optionally become positively charged
at a physiological pH to function as a sodium mimetic. In one
exemplary embodiment, the compound of the present disclosure (or
more particularly the pharmaceutically acceptable HCl salt thereof,
as illustrated) may have the structure of Formula (III):
##STR00028##
[0140] wherein Z may be optionally attached to any one of a number
of sites on the NHE-binding small molecule, and further wherein the
R.sub.1, R.sub.2 and R.sub.3 substituents on the aromatic rings are
as detailed elsewhere herein, and/or in U.S. Pat. No. 6,399,824,
the entire contents of which are incorporated herein by reference
for all relevant and consistent purposes.
[0141] In this regard it is to be noted, however, that the
substantially impermeable or substantially systemically
non-bioavailable NHE-binding compounds of the present disclosure
may have a structure other than illustrated above, without
departing from the scope of the present disclosure. For example, in
various alternative embodiments, one or both of the terminal
nitrogen atoms in the guanidine moiety may be substituted with one
or more substituents, and/or the modifying or functionalizing
moiety Z may be attached to the NHE-binding compound by means of
(i) the Scaffold, (ii) the spacer X, or (iii) the
heteroatom-containing moiety, B, as further illustrated generally
in the structures provided below:
##STR00029##
[0142] In this regard it is to be further noted that, as used
herein, "bioisostere" generally refers to a moiety with similar
physical and chemical properties to a guanidine moiety, which in
turn imparts biological properties to that given moiety similar to,
again, a guanidine moiety, in this instance. (See, for example,
Ahmad, S. et al., Aminoimidazoles as Bioisosteres of
Acylguanidines: Novel, Potent, Selective and Orally Bioavailable
Inhibitors of the Sodium Hydrogen Exchanger Isoform-1, Boorganic
& Med. Chem. Lett., pp. 177-180 (2004), the entire contents of
which is incorporated herein by reference for all relevant and
consistent purposes.)
[0143] As further detailed below, known NHE-binding small molecules
or chemotypes that may serve as suitable starting materials (for
modification or functionalization, in order to render the small
molecules substantially impermeable or substantially systemically
non-bioavailable, and/or used in pharmaceutical preparations) may
generally be organized into a number of subsets, such as for
example:
##STR00030##
[0144] wherein: the terminal ring (or, in the case of the non-acyl
guanidines, "R"), represent the scaffold or support moiety; the
guanidine moiety (or the substituted heterocycle, and more
specifically the piperidine ring, in the case of the non-guanidine
inhibitors) represents B; and, X is the acyl moiety, or the
-A-B-acyl- moiety (or a bond in the case of the non-acyl guanidines
and the non-guanidine inhibitors). (See, e.g., Lang, H. J.,
"Chemistry of NHE Inhibitors" in The Sodium-Hydrogen Exchanger,
Harmazyn, M., Avkiran, M. and Fliegel, L., Eds., Kluwer Academic
Publishers 2003. See also B. Masereel et al., An Overview of
Inhibitors of Na+/H+ Exchanger, European J. of Med. Chem., 38, pp.
547-554 (2003), the entire contents of which is incorporated by
reference here for all relevant and consistent purposes). Without
being held to any particular theory, it has been proposed that a
guanidine group, or an acylguanidine group, or a charged guanidine
or acylguanidine group (or, in the case of non-guanidine
inhibitors, a heterocycle or other functional group that can
replicate the molecular interactions of a guanidinyl functionality
including, but not limited to, a protonated nitrogen atom in a
piperidine ring) at physiological pH may mimic a sodium ion at the
binding site of the exchanger or antiporter (See, e.g., Vigne et
al., J. Biol. Chem. 1982, 257, 9394).
[0145] Although the heteroatom-containing moiety may be capable of
forming a positive charge, this should not be understood or
interpreted to require that the overall compound have a net
positive charge, or only a single positively charged moiety
therein, or even that the heteroatom-containing moiety therein be
capable of forming a positive charge in all instances. Rather, in
various alternative embodiments, the compound may have no charged
moieties therein, or it may have multiple charged moieties therein
(which may have positive charges, negative charges, or a
combination thereof). Additionally, it is to be understood that the
overall compound may have a net neutral charge, a net positive
charge, or a net negative charge.
[0146] In this regard it is to be noted that the U.S. patents and
U.S. Published applications cited above, or elsewhere herein, are
incorporated herein by reference in their entirety, for all
relevant and consistent purposes.
[0147] In addition to the structures illustrated above, and
elsewhere herein, it is to be noted that bioisosteric replacements
for guanidine or acylguanidine may also be used. Potentially viable
bioisosteric "guanidine replacements" identified to-date have a
five- or six-membered heterocyclic ring with donor/acceptor and pKa
patterns similar to that of guanidine or acylguanidine (see for
example Ahmad, S. et al., Aminoimidazoles as Bioisosteres of
Acylguanidines: Novel, Potent, Selective and Orally Bioavailable
Inhibitors of the Sodium Hydrogen Exchanger Isoform-1, Boorganic
& Med. Chem. Lett., pp. 177-180 (2004), the entire contents of
which is incorporated herein by reference for all relevant and
consistent purposes), and include those illustrated below:
##STR00031##
[0148] The above bioisosteric embodiments (i.e., the group of
structures above) correspond to "B" in the structure of Formula
(II), the broken bond therein being attached to "X" (e.g., the acyl
moiety, or alternatively a bond linking the bioisostere to the
scaffold), with bonds to Z in Formula (III) not shown here.
[0149] It is to be noted that, in the many structures illustrated
herein, all of the various linkages or bonds will not be shown in
every instance. For example, in one or more of the structures
illustrated above, a bond or connection between the NHE-binding
small molecule and the modifying or functionalizing moiety Z is not
always shown. However, this should not be viewed in a limiting
sense. Rather, it is to be understood that the NHE-binding small
molecule is bound or connected in some way (e.g., by a bond or
linker of some kind) to Z, such that the resulting NHE-Z molecule
is suitable for use (i.e., substantially impermeable or
substantially systemically non-bioavailable in the GI tract).
Alternatively, Z may be incorporated into the NHE-binding small
molecule, such as for example by positioning it between the
guanidine moiety and scaffold.
[0150] It is to be further noted that a number of structures are
provided herein for substantially impermeable or substantially
systemically non-bioavailable NHE-binding compounds, and/or for
NHE-binding small molecules suitable for modification or
functionalization in accordance with the present disclosure so as
to render them substantially impermeable or substantially
systemically non-bioavailable. Due to the large number of
structures, various identifiers (e.g., atom identifiers in a chain
or ring, identifiers for substituents on a ring or chain, etc.) may
be used more than once. An identifier in one structure should
therefore not be assumed to have the same meaning in a different
structure, unless specifically stated (e.g., "R.sub.1" in one
structure may or may not be the same as "R.sub.1" in another
structure). Additionally, it is to be noted that, in one or more of
the structures further illustrated herein below, specific details
of the structures, including one or more of the identifiers
therein, may be provided in a cited reference, the contents of
which are specifically incorporated herein by reference for all
relevant and consistent purposes.
C. Illustrative Small Molecule Embodiments
[0151] The substantially impermeable or substantially systemically
non-bioavailable NHE3-binding compounds of the present disclosure
may in general be derived or prepared from essentially any small
molecule possessing the ability to bind to and/or modulate NHE3,
including small molecules that have already been reported or
identified as binding to and/or modulating NHE3 activity but lack
impermeability (i.e., are not substantially impermeable). In one
particularly preferred embodiment, the compounds utilized in the
various methods of the present disclosure are derived or prepared
from small molecules that bind to the NHE3, -2, and/or -8 isoforms.
Although the present disclosure relates generally to NHE3-binding
compounds, compounds exhibiting NHE-2 and/or -8 binding or
inhibition are also of interest. However, while it is envisioned
that appropriate starting points may be the modification of known
NHE3, -2, and/or -8 binding or inhibiting small molecules, small
molecules identified for the binding or inhibition of other NHE
subtypes, including NHE-1, may also be of interest, and may be
optimized for selectivity and binding to the NHE3 subtype
antiporter.
[0152] Small molecules suitable for use (i.e., suitable for use as
substantially bioavailable compounds, suitable for modification or
functionalization to generate substantially systemically
non-bioavailable compounds) include those illustrated below. In
this regard it is to be noted a bond or link to Z (i.e., the
modification or functionalization that renders the small molecules
substantially impermeable or substantially systemically
non-bioavailable) is not specifically shown. As noted, the Z moiety
may be attached to, or included within, the small molecule at
essentially any site or position that does not interfere (e.g.,
sterically interfere) with the ability of the resulting compound to
effectively bind the NHE antiport of interest. More particularly, Z
may be attached to essentially any site on the NHE-binding small
molecule, Z for example displacing all or a portion of a
substituent initially or originally present thereon and as
illustrated below, provided that the site of installation of the Z
moiety does not have a substantially adversely impact on the
NHE-binding activity thereof. In one particular embodiment,
however, a bond or link extends from Z to a site on the small
molecule that effectively positions the point of attachment as far
away (based, for example, on the number of intervening atoms or
bonds) from the atom or atoms present in the resulting compound
that effectively act as the sodium ion mimic (for example, the atom
or atoms capable of forming a positive ion under physiological pH
conditions). In a preferred embodiment, the bond or link will
extend from Z to a site in a ring, and more preferably an aromatic
ring, within the small molecule, which serves as the scaffold.
[0153] In view of the foregoing, in one particular embodiment, the
following small molecule, disclosed in U.S. Patent Application No.
2005/0054705, the entire content of which (and in particular the
text of pages 1-2 therein) is incorporated herein by reference for
all relevant and consistent purposes, may be suitable for use or
modification in accordance with the present disclosure (e.g., bound
to or modified to include Z, such that the resulting NHE-Z molecule
is substantially impermeable or substantially systemically
non-bioavailable).
##STR00032##
[0154] The variables in the structure are defined in the cited
patent application, the details of which are incorporated herein by
reference. In one particularly preferred embodiment, R.sub.6 and
R.sub.7 are a halogen (e.g., Cl), R.sub.5 is lower alkyl (e.g.,
CH.sub.3), and R.sub.1-R.sub.4 are H, the compound having for
example the structure:
##STR00033##
[0155] In yet another particular embodiment, the following small
molecule, disclosed in Canadian Patent Application No. 2,241,531
(or International Patent Publication No. WO 97/24113), the entire
content of which (and in particular pages 1-2 therein) is
incorporated herein for all relevant and consistent purposes, may
be suitable for use or modification in accordance with the present
disclosure (e.g., bound to or modified to include Z, such that the
resulting NHE-Z molecule is substantially impermeable or
substantially systemically non-bioavailable).
##STR00034##
[0156] The variables in the structure are defined in the cited
patent application, the details of which are incorporated herein by
reference.
[0157] In yet another particular embodiment, the following small
molecule, disclosed in Canadian Patent Application No. 2,241,531
(or International Patent Publication No. WO 97/24113), the entire
content of which (and in particular page 49 therein) is
incorporated herein for all relevant and consistent purposes, may
be suitable for use or modification in accordance with the present
disclosure (e.g., bound to or modified to include Z, such that the
resulting NHE-Z molecule is substantially impermeable or
substantially systemically non-bioavailable).
##STR00035##
[0158] The variables in the structure are defined in the cited
patent application, the details of which are incorporated herein by
reference.
[0159] In yet another particular embodiment, the following small
molecule, disclosed in Canadian Patent Application No. 2,241,531
(or International Patent Publication No. WO 97/24113), the entire
content of which (and in particular pages 118-120 and 175-177
therein) is incorporated herein for all relevant and consistent
purposes, may be suitable for use or modification in accordance
with the present disclosure (e.g., bound to or modified to include
Z, such that the resulting NHE-Z molecule is substantially
impermeable or substantially systemically non-bioavailable).
##STR00036##
[0160] The variables in the structure are defined in the cited
patent application, the details of which are incorporated herein by
reference.
[0161] In yet another particular embodiment, the following small
molecule, disclosed in Canadian Patent Application No. 2,241,531
(or International Patent Publication No. WO 97/24113), the entire
content of which (and in particular pages 129-131 therein) is
incorporated herein for all relevant and consistent purposes, may
be suitable for use or modification in accordance with the present
disclosure (e.g., bound to or modified to include Z, such that the
resulting NHE-Z molecule is substantially impermeable or
substantially systemically non-bioavailable).
##STR00037##
[0162] The variables in the structure are defined in the cited
patent application, the details of which are incorporated herein by
reference. (In this regard it is to be noted that the substituent Z
within the structure illustrated above is not to be confused with
the moiety Z that, in accordance with the present disclosure, is
attached to the NHE-binding small molecule in order effective
render the resulting "NHE-Z" molecule substantially
impermeable.).
[0163] In yet another particular embodiment, the following small
molecule, disclosed in Canadian Patent Application No. 2,241,531
(or International Patent Publication No. WO 97/24113), the entire
content of which (and in particular pages 127-129 therein) is
incorporated herein for all relevant and consistent purposes, may
be suitable for use or modification in accordance with the present
disclosure (e.g., bound to or modified to include Z, such that the
resulting NHE-Z molecule is substantially impermeable or
substantially systemically non-bioavailable).
##STR00038##
[0164] The variables in the structure are defined in the cited
patent application, the details of which are incorporated herein by
reference. (In this regard it is to be noted that Z within the ring
of the structure illustrated above is not to be confused with the
moiety Z that, in accordance with the present disclosure, is
attached to the NHE-binding small molecule in order effective
render the resulting "NHE-Z" molecule substantially
impermeable.)
[0165] In yet another particular embodiment, the following small
molecule, disclosed in Canadian Patent Application No. 2,241,531
(or International Patent Publication No. WO 97/24113), the entire
content of which (and in particular pages 134-137 therein) is
incorporated herein for all relevant and consistent purposes, may
be suitable for use or modification in accordance with the present
disclosure (e.g., bound to or modified to include Z, such that the
resulting NHE-Z molecule is substantially impermeable or
substantially systemically non-bioavailable).
##STR00039##
[0166] The variables in the structure are defined in the cited
patent application, the details of which are incorporated herein by
reference.
[0167] In yet another particular embodiment, the following small
molecule, disclosed in Canadian Patent Application No. 2,241,531
(or International Patent Publication No. WO 97/24113), the entire
content of which (and in particular pages 31-32 and 137-139
therein) is incorporated herein for all relevant and consistent
purposes, may be suitable for use or modification in accordance
with the present disclosure (e.g., bound to or modified to include
Z, such that the resulting NHE-Z molecule is substantially
impermeable or substantially systemically non-bioavailable).
##STR00040##
[0168] The variables in the structure are defined in the cited
patent application, the details of which are incorporated herein by
reference.
[0169] In yet another particular embodiment, the following small
molecule, disclosed in Canadian Patent Application No. 2,241,531
(or International Patent Publication No. WO 97/24113), the entire
content of which (and in particular pages 37-45 therein) is
incorporated herein for all relevant and consistent purposes, may
be suitable for use or modification in accordance with the present
disclosure (e.g., bound to or modified to include Z, such that the
resulting NHE-Z molecule is substantially impermeable or
substantially systemically non-bioavailable).
##STR00041##
[0170] The variables in the structure are defined in the cited
patent application, the details of which are incorporated herein by
reference. (In this regard it is to be noted that Z within the ring
structure illustrated above is not to be confused with the moiety Z
that, in accordance with the present disclosure, is attached to the
NHE-binding small molecule in order effective render the
resulting
[0171] "NHE-Z" molecule substantially impermeable.) In yet another
particular embodiment, the following small molecule, disclosed in
Canadian Patent Application No. 2,241,531 (or International Patent
Publication No. WO 97/24113), the entire content of which (and in
particular pages 100-102 therein) is incorporated herein for all
relevant and consistent purposes, may be suitable for use or
modification in accordance with the present disclosure (e.g., bound
to or modified to include Z, such that the resulting NHE-Z molecule
is substantially impermeable or substantially systemically
non-bioavailable).
##STR00042##
[0172] The variables in the structure are defined in the cited
patent application, the details of which are incorporated herein by
reference (wherein, in particular, the wavy bonds indicate variable
length, or a variable number of atoms, therein).
[0173] In yet another particular embodiment, the following small
molecule, disclosed in Canadian Patent Application No. 2,241,531
(or International Patent Publication No. WO 97/24113), the entire
content of which (and in particular pages 90-91 therein) is
incorporated herein for all relevant and consistent purposes, may
be suitable for use or modification in accordance with the present
disclosure (e.g., bound to or modified to include Z, such that the
resulting NHE-Z molecule is substantially impermeable or
substantially systemically non-bioavailable).
##STR00043##
[0174] The variables in the structure are defined in the cited
patent application, the details of which are incorporated herein by
reference.
[0175] In yet another particular embodiment, the following small
molecule, disclosed in U.S. Pat. No. 5,900,436 (or EP 0822182 B1),
the entire contents of which (and in particular column 1, lines
10-55 therein) are incorporated herein by reference for all
relevant and consistent purposes, may be suitable for use or
modification in accordance with the present disclosure (e.g., bound
to or modified to include Z, such that the resulting NHE-Z molecule
is substantially impermeable or substantially systemically
non-bioavailable).
##STR00044##
[0176] The variables in the structures are defined in the cited
patents, the details of which are incorporated herein by
reference.
[0177] In yet another particular embodiment, the following small
molecule, disclosed in Canadian Patent Application No. 2,241,531
(or International Patent Publication No. WO 97/24113), the entire
content of which (and in particular pages 35-47 therein) is
incorporated herein for all relevant and consistent purposes, may
be suitable for use or modification in accordance with the present
disclosure (e.g., bound to or modified to include Z, such that the
resulting NHE-Z molecule is substantially impermeable or
substantially systemically non-bioavailable).
##STR00045##
[0178] The variables in the structure are defined in the cited
patent application, the details of which are incorporated herein by
reference.
[0179] In yet another particular embodiment, the following small
molecule, disclosed in Canadian Patent Application No. 2,241,531
(or International Patent Publication No. WO 97/24113), the entire
content of which (and in particular pages 154-155 therein) is
incorporated herein for all relevant and consistent purposes, may
be suitable for use or modification in accordance with the present
disclosure (e.g., bound to or modified to include Z, such that the
resulting NHE-Z molecule is substantially impermeable or
substantially systemically non-bioavailable).
##STR00046##
[0180] The variables in the structure are defined in the cited
patent application, the details of which are incorporated herein by
reference.
[0181] In yet another particular embodiment, the following small
molecule, disclosed in Canadian Patent Application No. 2,241,531
(or International Patent Publication No. WO 97/24113), the entire
content of which (and in particular pages 132-133 therein) is
incorporated herein for all relevant and consistent purposes, may
be suitable for use or modification in accordance with the present
disclosure (e.g., bound to or modified to include Z, such that the
resulting NHE-Z molecule is substantially impermeable or
substantially systemically non-bioavailable).
##STR00047##
[0182] The variables in the structure are defined in the cited
patent application, the details of which are incorporated herein by
reference.
[0183] In yet another particular embodiment, the following small
molecule, disclosed in Canadian Patent Application No. 2,241,531
(or International Patent Publication No. WO 97/24113), the entire
content of which (and in particular pages 58-65 AND 141-148
therein) is incorporated herein for all relevant and consistent
purposes, may be suitable for use or modification in accordance
with the present disclosure (e.g., bound to or modified to include
Z, such that the resulting NHE-Z molecule is substantially
impermeable or substantially systemically non-bioavailable).
##STR00048##
[0184] The variables in the structure are defined in the cited
patent application, the details of which are incorporated herein by
reference. (In this regard it is to be noted that Z within the ring
structure illustrated above is not to be confused with the moiety Z
that, in accordance with the present disclosure, is attached to the
NHE-binding small molecule in order effective render the resulting
"NHE-Z" molecule substantially impermeable.)
[0185] In yet another particular embodiment, the following small
molecule, disclosed in U.S. Pat. Nos. 6,911,453 and 6,703,405, the
entire contents of which (and in particular the text of columns 1-7
and 46 of U.S. Pat. No. 6,911,453 and columns 14-15 of U.S. Pat.
No. 6,703,405) are incorporated herein by reference for all
relevant and consistent purposes, may be suitable for use or
modification in accordance with the present disclosure (e.g., bound
to or modified to include Z, such that the resulting NHE-Z molecule
is substantially impermeable or substantially systemically
non-bioavailable).
##STR00049##
[0186] The variables in the structure are defined in the cited
patents, the details of which are incorporated herein by reference.
A particularly preferred small molecule falling within the
above-noted structure is further illustrated below (see, e.g.,
Example 1 of the U.S. Pat. No. 6,911,453, the entire contents of
which are specifically incorporated herein by reference):
##STR00050##
[0187] In yet another particular embodiment, the following small
molecules, disclosed in U.S. Patent Publication Nos. 2004/0039001,
2004/0224965, 2005/0113396 and 2005/0020612, the entire contents of
which are incorporated herein by reference for all relevant and
consistent purposes, may be suitable for use or modification in
accordance with the present disclosure (e.g., bound to or modified
to include Z, such that the resulting NHE-Z molecule is
substantially impermeable or substantially systemically
non-bioavailable).
##STR00051##
[0188] The variables in the structures are defined above and/or in
one or more of the cited patent applications, the details of which
are incorporated herein by reference, and/or as illustrated above
(wherein the broken bonds indicate a point of attachment for the Y
moiety to the fused heterocyclic ring). In particular, in various
embodiments the combination of X and Y may be as follows:
##STR00052##
[0189] In a particularly preferred embodiment of the above-noted
structure, the small molecule has the general structure:
##STR00053##
[0190] wherein R.sub.1, R.sub.2 and R.sub.3 may be the same or
different, but are preferably different, and are independently
selected from H, NR'R'' (wherein R' and R'' are independently
selected from H and hydrocarbyl, such as lower alkyl, as defined
elsewhere herein) and the structure:
##STR00054##
[0191] In a more particularly preferred embodiment of the above
structure, a small molecule falling within the above-noted
structure is further illustrated below (see, e.g., compound I1 on
p. 5 of the 2005/0020612 patent application, the entire contents of
which are specifically incorporated herein by reference):
##STR00055##
[0192] In another particularly preferred embodiment, the following
small molecule, disclosed in U.S. Pat. No. 6,399,824, the entire
content of which (and in particular the text of Example 1 therein)
is incorporated herein by reference for all relevant and consistent
purposes, may be particularly suitable for use or modification in
accordance with the present disclosure (e.g., bound to or modified
to include Z, such that the resulting NHE-Z molecule is
substantially impermeable or substantially systemically
non-bioavailable).
##STR00056##
[0193] In the structure, R may be preferably selected from H and
(CH.sub.3).sub.2NCH.sub.2CH.sub.2--, with H being particularly
preferred in various embodiments.
[0194] In yet another particular embodiment, the following small
molecule, disclosed in U.S. Pat. No. 6,005,010 (and in particular
columns 1-3 therein), and/or U.S. Pat. No. 6,166,002 (and in
particular columns 1-3 therein), the entire contents of which are
incorporated herein by reference for all relevant and consistent
purposes, may be suitable for use or modification in accordance
with the present disclosure (e.g., bound to or modified to include
Z, such that the resulting NHE-Z molecule is substantially
impermeable or substantially systemically non-bioavailable).
##STR00057##
[0195] The variable ("R") in the structure is defined in the cited
patent application, the details of which are incorporated herein by
reference.
[0196] In yet another particularly preferred embodiment, the
following small molecule, disclosed in U.S. Patent Application No.
2008/0194621, the entire content of which (and in particular the
text of Example 1 therein) is incorporated herein by reference for
all relevant and consistent purposes, may be particularly suitable
for use or modification in accordance with the present disclosure
(e.g., bound to or modified to include Z, such that the resulting
NHE-Z molecule is substantially impermeable or substantially
systemically non-bioavailable).
TABLE-US-00002 ##STR00058## R.sub.1 R.sub.2 R.sub.3 ##STR00059##
--H --H --NH.sub.2 --H --H --H ##STR00060## --H --H --NH.sub.2 --H
--H --H --NH.sub.2
[0197] The variables ("R.sub.1", "R.sub.2 and "R.sub.3") in the
structure are as defined above, and/or as defined in the cited
patent application, the details of which are incorporated herein by
reference.
[0198] In yet another particularly preferred embodiment, the
following small molecule, disclosed in U.S. Patent Application No.
2007/0225323, the entire content of which (and in particular the
text of Example 36 therein) is incorporated herein by reference for
all relevant and consistent purposes, may be particularly suitable
for use or modification in accordance with the present disclosure
(e.g., bound to or modified to include Z, such that the resulting
NHE-Z molecule is substantially impermeable or substantially
systemically non-bioavailable).
##STR00061##
[0199] In yet another particularly preferred embodiment, the
following small molecule, disclosed in U.S. Pat. No. 6,911,453, the
entire content of which (and in particular the text of Example 35
therein) is incorporated herein by reference for all relevant and
consistent purposes, may be particularly suitable for use or
modification in accordance with the present disclosure (e.g., bound
to or modified to include Z, such that the resulting NHE-Z molecule
is substantially impermeable or substantially systemically
non-bioavailable).
##STR00062##
[0200] In one particularly preferred embodiment of the present
disclosure, the small molecule may be selected from the group
consisting of:
##STR00063##
[0201] In these structures, a bond or link (not shown) may extend,
for example, between the Core and amine-substituted aromatic ring
(first structure), the heterocyclic ring or the aromatic ring to
which it is bound, or alternatively the chloro-substituted aromatic
ring (second structure), or the difluoro-substituted aromatic ring
or the sulfonamide-substituted aromatic ring (third structure).
D. Exemplary Small Molecule Selectivity
[0202] Shown below are examples of various NHE binding small
molecules and their selectivity across the NHE-1, -2 and -3
isoforms. (See, e.g., B. Masereel et al., An Overview of Inhibitors
of Na+/H+ Exchanger, European J. of Med. Chem., 38, pp. 547-554
(2003), the entire contents of which is incorporated by reference
here for all relevant and consistent purposes). Most of these small
molecules were optimized as NHE-1 inhibitors, and this is reflected
in their selectivity with respect thereto (IC50's for subtype-1 are
significantly more potent (numerically lower) than for subtype-3).
However, the data in Table 2 indicates that NHE3 binding activity
may be engineered into a compound series originally optimized
against a different isoform. For example, amiloride is a poor NHE3
binder/inhibitor and was inactive against this antiporter at the
highest concentration tested (IC50>100 .mu.M); however, analogs
of this compound, such as DMA and EIPA, have NHE3 IC50's of 14 and
2.4 .mu.M, respectively. The cinnamoylguanidine S-2120 is over
500-fold more active against NHE-1 than NHE3; however, this
selectivity is reversed in regioisomer S-3226. It is thus possible
to engineer NHE3 binding selectivity into a chemical series
optimized for potency against another antiporter isoform; that is,
the inhibitor classes exemplified in the art may be suitably
modified for activity and selectivity against NHE3 (or
alternatively NHE-2 and/or NHE-8), as well as being optionally
modified to be rendered substantially impermeable or substantially
systemically non-bioavailable.
##STR00064## ##STR00065##
TABLE-US-00003 TABLE 2 IC.sub.50 or K.sub.i (.mu.M).sup.b Drug
.sup.a NHE-1 NHE-2 NHE-3 NHE-5 Amiloride 1-1.6* 1.0** >100* 21
EIPA 0.01*-0.02** 0.08*-0.5** 2.4* 0.42 HMA 0.013* -- 2.4* 0.37 DMA
0.023* 0.25* 14* -- Cariporide 0.03-3.4 4.3-62 1->100 >30
Eniporide 0.005-0.38 2-17 100-460 >30 Zoniporide 0.059 12
>500* -- BMS-284640 0.009 1800 >30 3.36 T-162559 (S) 0.001
0.43 11 -- T-162559 (R) 35 0.31 >30 -- S-3226 3.6 80** 0.02
S-2120 0.002 0.07 1.32 * = from rat, ** = from rabbit. NA = not
active .sup.aTable adapted from Masereel, B. et al., European
Journal of Medicinal Chemistry, 2003, 38, 547-54. .sup.bK.sub.i
values are in italic
[0203] As previously noted above, the NHE-binding small molecules
disclosed herein, including those noted above, may advantageously
be modified to render them substantially impermeable or
substantially systemically non-bioavailable. The compounds as
described herein are, accordingly, effectively localized in the
gastrointestinal tract or lumen, and in one particular embodiment
the colon. Since the various NHE isoforms may be found in many
different internal organs (e.g., brain, heart, liver, etc.),
localization of the NHE binding compounds in the intestinal lumen
can be desirable in order to minimize or eliminate systemic effects
(i.e., prevent or significantly limit exposure of such organs to
these compounds). Accordingly, the present disclosure provides NHE
binding compounds, and in particular NHE3, -2 and/or -8 inhibitors,
which are substantially systemically non-bioavailable in the GI
tract, and more specifically substantially systemically impermeable
to the gut epithelium, as further described herein.
E. Exemplary Embodiments
[0204] In one or more particularly preferred embodiments of the
present disclosure, the "NHE-Z" molecule is monovalent; that is,
the molecule contains one moiety that effectively binds to and/or
modulates NHE3 and also inhibits phosphate transport in the GI
tract or kidneys. In such embodiments, the NHE-Z molecule may be
selected, for example, from one of the following structures of
Formulas (IV), (V), (VI) or (VII):
##STR00066##
wherein: each R.sub.1, R.sub.2, R.sub.3, R.sub.5 and R.sub.9 are
independently selected from H, halogen (e.g., Cl),
--NR.sub.7(CO)R.sub.8, --(CO)NR.sub.7R.sub.8,
--SO.sub.2--NR.sub.7R.sub.8, --NR.sub.7SO.sub.2R.sub.8,
--NR.sub.7R.sub.8, --OR.sub.7, --SR.sub.7, --O(CO)NR.sub.7R.sub.8,
--NR.sub.7(CO)OR.sub.8, and --NR.sub.7SO.sub.2NR.sub.8, where
R.sub.7 and R.sub.8 are independently selected from H or Z, where Z
is selected from substituted or unsubstituted hydrocarbyl,
heterohydrocarbyl, polyalkylene glycol and polyols, where
substituents thereon are selected from hydroxyls, amines, amidines,
carboxylates, phosphonates, sulfonates, and guanidines; R.sub.4 is
selected from H, C.sub.1-C.sub.7 alkyl or Z, where Z is selected
from substituted or unsubstituted hydrocarbyl, heterohydrocarbyl, a
polyalkylene glycol and polyols, where substituents thereon are
selected from hydroxyls, amines, amidines, carboxylates,
phosphonates, sulfonates, and guanidines; R.sub.6 is absent or
selected from H and C.sub.1-C.sub.7 alkyl; and, Ar1 and Ar2
independently represent an aromatic ring, or alternatively a
heteroaromatic ring wherein one or more of the carbon atoms therein
is replaced with a N, O or S atom;
##STR00067##
wherein: each R.sub.1, R.sub.2, R.sub.3, and R.sub.5 are
independently selected from H, --NR.sub.7(CO)R.sub.8,
--(CO)NR.sub.7R.sub.8, --SO.sub.2--NR.sub.7R.sub.8,
--NR.sub.7SO.sub.2R.sub.8, --NR.sub.7R.sub.8, --OR.sub.7,
--SR.sub.7, --O(CO)NR.sub.7R.sub.8, --NR.sub.7(CO)OR.sub.8, and
--NR.sub.7SO.sub.2NR.sub.8, where R.sub.7 and R.sub.8 are
independently selected from H or Z, where Z is selected from
substituted or unsubstituted hydrocarbyl, heterohydrocarbyl,
polyalkylene glycol and polyols, where substituents thereon are
selected from hydroxyls, amines, amidines, carboxylates,
phosphonates, sulfonates, and guanidines, optionally linked to the
ring Ar1 by a heterocyclic linker; R.sub.4 and R.sub.12 are
independently selected from H and R.sub.7, where R.sub.7 is as
defined above; R.sub.10 and R.sub.11, when presented, are
independently selected from H and C.sub.1-C.sub.7 alkyl; and, Ar1
and Ar2 independently represent an aromatic ring, or alternatively
a heteroaromatic ring wherein one or more of the carbon atoms
therein is replaced with a N, O or S atom;
##STR00068##
wherein: each X is a halogen atom, which may be the same or
different; R.sub.1 is selected from --SO.sub.2--NR.sub.7R.sub.8,
--NR.sub.7(CO)R.sub.8, --(CO)NR.sub.7R.sub.8,
--NR.sub.7SO.sub.2R.sub.8, --NR.sub.7R.sub.8, --OR.sub.7,
--SR.sub.7, --O(CO)NR.sub.7R.sub.8, --NR.sub.7(CO)OR.sub.8, and
--NR.sub.7SO.sub.2NR.sub.8, where R.sub.7 and R.sub.8 are
independently selected from H or Z, where Z is selected from
substituted or unsubstituted hydrocarbyl, heterohydrocarbyl,
polyalkylene glycol and polyols, where substituents thereon are
selected from hydroxyls, amines, amidines, carboxylates,
phosphonates, sulfonates, and guanidines; R.sub.3 is selected from
H or R.sub.7, where R.sub.7 is as described above; R.sub.13 is
selected from substituted or unsubstituted C.sub.1-C.sub.8 alkyl;
R.sub.2 and R.sub.12 are independently selected from H or R.sub.7,
wherein R.sub.7 is as described above; R.sub.10 and R.sub.11, when
present, are independently selected from H and C.sub.1-C.sub.7
alkyl; Ar1 represents an aromatic ring, or alternatively a
heteroaromatic ring wherein one or more of the carbon atoms therein
is replaced with a N, O or S atom; and Ar2 represents an aromatic
ring, or alternatively a heteroaromatic ring wherein one or more of
the carbon atoms therein is replaced with a N, O or S atom.
[0205] In one particular embodiment for the structure of Formula
(V), one of R.sub.1, R.sub.2 and R.sub.3 is linked to the ring Ar1,
and/or R.sub.5 is linked to the ring Ar2, by a heterocyclic linker
having the structure:
##STR00069##
[0206] wherein R represents R.sub.1, R.sub.2, R.sub.3, or R.sub.5
bound thereto.
[0207] In another particular embodiment, the NHE-Z molecule of the
present disclosure may have the structure of Formula (IV):
##STR00070##
[0208] wherein: each R.sub.1, R.sub.2, R.sub.3, R.sub.5 and R.sub.9
are independently selected from H, halogen, NR.sub.7(CO)R.sub.8,
--(CO)NR.sub.7R.sub.8, --SO.sub.2--NR.sub.7R.sub.8,
--NR.sub.7SO.sub.2R.sub.8, --NR.sub.7R.sub.8, --OR.sub.7,
--SR.sub.7, --O(CO)NR.sub.7R.sub.8, --NR.sub.7(CO)OR.sub.8, and
--NR.sub.7SO.sub.2NR.sub.8, where R.sub.7 and R.sub.8 are
independently selected from H or Z, where Z is selected from
substituted hydrocarbyl, heterohydrocarbyl, or polyols and/or
substituted or unsubstituted polyalkylene glycol, wherein
substituents thereon are selected from the group consisting of
phosphinates, phosphonates, phosphonamidates, phosphates,
phosphonthioates and phosphonodithioates; R.sub.4 is selected from
H or Z, where Z is substituted or unsubstituted hydrocarbyl,
heterohydrocarbyl, a polyalkylene glycol and a polyol, where
substituents thereon are selected from hydroxyls, amines, amidines,
carboxylates, phosphonates, sulfonates, and guanidines; R.sub.6 is
selected from --H and C.sub.1-C.sub.7 alkyl; and, Ar1 and Ar2
independently represent an aromatic ring, or alternatively a
heteroaromatic ring wherein one or more of the carbon atoms therein
is replaced with a N, O or S atom.
[0209] Additionally, or alternatively, in one or more embodiments
of the compounds illustrated above, the compound may optionally
have a tPSA of at least about 100 .ANG..sup.2, about 150
.ANG..sup.2, about 200 .ANG..sup.2, about 250 .ANG..sup.2, about
270 .ANG..sup.2, or more and/or a molecular weight of at least
about 710 Da.
F. Polyvalent Structures: Macromolecules and Oligomers
[0210] (i). General Structure
[0211] As noted above, certain embodiments relate to NHE-binding
small molecules that have been modified or functionalized
structurally to alter its physicochemical properties (by the
attachment or inclusion of moiety Z), and more specifically the
physicochemical properties of the NHE-Z molecule, thus rendering it
substantially impermeable or substantially systemically
non-bioavailable. In one particular embodiment, and as further
detailed elsewhere herein, the NHE-Z compound may be polyvalent
(i.e., an oligomer, dendrimer or polymer moiety), wherein Z may be
referred to in this embodiment generally as a "Core" moiety, and
the NHE-binding small molecule may be bound, directly or indirectly
(by means of a linking moiety) thereto, the polyvalent compounds
having for example one of the following general structures of
Formula (VIII), (IX) and (X):
##STR00071##
[0212] wherein: Core (or Z) and NHE are as defined above; L is a
bond or linker, as further defined elsewhere herein below, and E
and n are both an integer of 2 or more. In various alternative
embodiments, however, the NHE-binding small molecule may be
rendered substantially impermeable or substantially systemically
non-bioavailable by forming a polymeric structure from multiple
NHE-binding small molecules, which may be the same or different,
connected or bound by a series of linkers, L, which also may be the
same or different, the compound having for example the structure of
Formula (XI):
##STR00072##
[0213] wherein: Core (or Z) and NHE are as defined above; L is a
bond or linker, as further defined elsewhere herein below, and m is
0 or an integer of 1 or more. In this embodiment, the
physicochemical properties, and in particular the molecular weight
or polar surface area, of the NHE-binding small molecule is
modified (e.g., increased) by having a series of NHE-binding small
molecules linked together, in order to render them substantially
impermeable or substantially systemically non-bioavailable. In
these or yet additional alternative embodiments, the polyvalent
compound may be in dimeric, oligomeric or polymeric form, wherein
for example Z or the Core is a backbone to which is bound (by means
of a linker, for example) multiple NHE-binding small molecules.
Such compounds may have, for example, the structures of Formulas
(XIIA) or (XIIB):
##STR00073##
[0214] wherein: L is a linking moiety; NHE is a NHE-binding small
molecule, each NHE as described above and in further detail
hereinafter; and n is a non-zero integer (i.e., an integer of 1 or
more).
[0215] The Core moiety has one or more attachment sites to which
NHE-binding small molecules are bound, and preferably covalently
bound, via a bond or linker, L. The Core moiety may, in general, be
anything that serves to enable the overall compound to be
substantially impermeable or substantially systemically
non-bioavailable (e.g., an atom, a small molecule, etc.), but in
one or more preferred embodiments is an oligomer, a dendrimer or a
polymer moiety, in each case having more than one site of
attachment for L (and thus for the NHE-binding small molecule). The
combination of the Core and NHE-binding small molecule (i.e., the
"NHE-Z" molecule) may have physicochemical properties that enable
the overall compound to be substantially impermeable or
substantially systemically non-bioavailable.
[0216] In this regard it is to be noted that the repeat unit in
Formulas (XIIA) and (XIIB) generally encompasses repeating units of
various polymeric embodiments, which may optionally be produced by
methods referred to herein. In each polymeric, or more general
polyvalent, embodiment, it is to be noted that each repeat unit may
be the same or different, and may or may not be linked to the
NHE-binding small molecule by a linker, which in turn may be the
same or different when present. In this regard it is to be noted
that as used herein, "polyvalent" refers to a molecule that has
multiple (e.g., 2, 4, 6, 8, 10 or more) NHE-binding moieties
therein.
[0217] The above noted embodiments are further illustrated herein
below. For example, the first representation below of an exemplary
oligomer compound, wherein the various parts of the compound
corresponding to the structure of Formula (X) are identified, is
intended to provide a broad context for the disclosure provided
herein. It is to be noted that while each "NHE" moiety (i.e., the
NHE small molecule) in the structure below is the same, it is
within the scope of this disclosure that each is independently
selected and may be the same or different. In the illustration
below, the linker moiety is a polyethylene glycol (PEG) motif PEG
derivatives are advantageous due in part to their aqueous
solubility, which may help avoid hydrophobic collapse (the
intramolecular interaction of hydrophobic motifs that can occur
when a hydrophobic molecule is exposed to an aqueous environment
(see, e.g., Wiley, R. A.; Rich, D. H. Medical Research Reviews
1993, 13(3), 327-384). The core moiety illustrated below is also
advantageous because it provides some rigidity to the
Core-(L-NHE).sub.n molecule, allowing an increase in distance
between the NHE-binding compounds while minimally increasing
rotational degrees of freedom.
##STR00074##
[0218] In an alternative embodiment (e.g., Formula (XI), wherein
m=0), the structure may be for example:
##STR00075##
[0219] Within the polyvalent compounds utilized for treatments
according to the present disclosure, n and m (when m is not zero)
may be independently selected from the range of from about 1 to
about 10, more preferably from about 1 to about 5, and even more
preferably from about 1 to about 2. In alternative embodiments,
however, n and m may be independently selected from the range of
from about 1 to about 500, preferably from about 1 to about 300,
more preferably from about 1 to about 100, and most preferably from
about 1 to about 50. In these or other particular embodiments, n
and m may both be within the range of from about 1 to about 50, or
from about 1 to about 20.
[0220] The structures provided above are illustrations of one
embodiment of compounds utilized for administration wherein
absorption is limited (i.e., the compound is rendered substantially
impermeable or substantially systemically non-bioavailable) by
means of increasing the molecular weight of the NHE-binding small
molecule. In an alternative approach, as noted elsewhere herein,
the NHE-binding small molecule may be rendered substantially
impermeable or substantially systemically non-bioavailable by means
of altering, and more specifically increasing, the topological
polar surface area, as further illustrated by the following
structures, wherein a substituted aromatic ring is bound to the
"scaffold" of the NHE-binding small molecule. The selection of
ionizable groups such as phosphonates, sulfonates, guanidines and
the like may be particularly advantageous at preventing
paracellular permeability. Carbohydrates are also advantageous, and
though uncharged, significantly increase tPSA while minimally
increasing molecular weight.
##STR00076##
[0221] It is to be noted, within one or more of the various
embodiments illustrated herein, NHE-binding small molecules
suitable for use (i.e., suitable for use as substantially
bioavailable compounds, suitable for modification or
functionalization, in order to render them substantially
impermeable or substantially systemically non-bioavailable) may, in
particular, be selected independently from one or more of the small
molecules described as benzoylguandines, heteroaroylguandines,
"spacer-stretched" aroylguandines, non-acyl guanidines and
acylguanidine isosteres, above, and as discussed in further detail
hereinafter and/or to the small molecules detailed in, for example:
U.S. Pat. Nos. 5,866,610; 6,399,824; 6,911,453; 6,703,405;
6,005,010; 6,887,870; 6,737,423; 7,326,705; 55,824,691
(WO94/026709); U.S. Pat. No. 6,399,824 (WO02/024637); US
2004/0339001 (WO02/020496); US 2005/0020612 (WO03/055490);
WO01/072742; CA 2387529 (WO01021582); CA 02241531 (WO97/024113); US
2005/0113396 (WO03/051866); US2005/0020612; US2005/0054705;
US2008/0194621; US2007/0225323; US2004/0039001; US2004/0224965;
US2005/0113396; US2007/0135383; US2007/0135385; US2005/0244367;
US2007/0270414; and CA 2177007 (EP0744397), the entire contents of
which are incorporated herein by reference for all relevant and
consistent purposes. Again, it is to be noted that when it is said
that NHE-binding small molecule is selected independently, it is
intended that, for example, the oligomeric structures represented
in Formulas (X) and (XI) above can include different structures of
the NHE small molecules, within the same oligomer or polymer. In
other words, each "NHE" within a given polyvalent embodiment may
independently be the same or different than other "NHE" moieties
within the same polyvalent embodiment.
[0222] In designing and making the substantially impermeable or
substantially systemically non-bioavailable, NHE-binding compounds
that may be utilized for the treatments detailed in the instant
disclosure, it may in some cases be advantageous to first determine
a likely point of attachment on a small molecule NHE-binding
compound, where a core or linker might be installed or attached
before making a series of candidate multivalent or polyvalent
compounds. This may be done by one skilled in the art via known
methods by systematically installing functional groups, or
functional groups displaying a fragment of the desired core or
linker, onto various positions of the NHE-binding small molecule
and then testing these adducts to determine whether the modified
compound still retains desired biological properties (e.g., NHE3
binding and/or modulation, inhibition of phosphate transport). An
understanding of the SAR of the compound also allows the design of
cores and/or linkers that contribute positively to the activity of
the resulting compounds. For example, the SAR of an NHE-binding
compound series may show that installation of an N-alkylated
piperazine contributes positively to biochemical activity
(increased potency) or pharmaceutical properties (increased
solubility); the piperazine moiety may then be utilized as the
point of attachment for the desired core or linker via
N-alkylation. In this fashion, the resulting compound thereby
retains the favorable biochemical or pharmaceutical properties of
the parent small molecule. In another example, the SAR of an
NHE-binding compound series might indicate that a hydrogen bond
donor is important for activity or selectivity. Core or linker
moieties may then be designed to ensure this H-bond donor is
retained. These cores and/or linkers may be further designed to
attenuate or potentiate the pKa of the H-bond donor, potentially
allowing improvements in potency and selectivity. In another
scenario, an aromatic ring in a compound could be an important
pharmacophore, interacting with the biological target via a
pi-stacking effect or pi-cation interaction. Linker and core motifs
may be similarly designed to be isosteric or otherwise synergize
with the aromatic features of the small molecule. Accordingly, once
the structure-activity relationships within a molecular series are
understood, the molecules of interest can be broken down into key
pharmacophores which act as essential molecular recognition
elements. When considering the installation of a core or linker
motif, said motifs can be designed to exploit this SAR and may be
installed to be isosteric and isoelectronic with these motifs,
resulting in compounds that retain biological activity but have
significantly reduced permeability.
[0223] Another way the SAR of a compound series can be exploited in
the installation of core or linker groups is to understand which
regions of the molecule are insensitive to structural changes. For
example, X-ray co-crystal structures of protein-bound compounds can
reveal those portions of the compound that are solvent exposed and
not involved in productive interactions with the target. Such
regions can also be identified empirically when chemical
modifications in these regions result in a "flat SAR" (i.e.,
modifications appear to have minimal contribution to biochemical
activity). Those skilled in the art have frequently exploited such
regions to engineer in pharmaceutical properties into a compound,
for example, by installing motifs that may improve solubility or
potentiate ADME properties. In the same fashion, such regions are
expected to be advantageous places to install core or linker groups
to create compounds as described in the instant disclosure. These
regions are also expected to be sites for adding, for example,
highly polar functionality such as carboxylic acids, phosphonic
acids, sulfonic acids, and the like in order to greatly increase
tPSA.
[0224] Another aspect to be considered in the design of cores and
linkers displaying an NHE-binding activity is the limiting or
preventing of hydrophobic collapse. Compounds with extended
hydrocarbon functionalities may collapse upon themselves in an
intramolecular fashion, causing an increased enthalpic barrier for
interaction with the desired biological target. Accordingly, when
designing cores and linkers, these are preferably designed to be
resistant to hydrophobic collapse. For example, conformational
constraints such as rigid monocyclic, bicyclic or polycyclic rings
can be installed in a core or linker to increase the rigidity of
the structure. Unsaturated bonds, such as alkenes and alkynes, may
also or alternatively be installed. Such modifications may ensure
the NHE-binding compound is accessible for productive binding with
its target. Furthermore, the hydrophilicity of the linkers may be
improved by adding hydrogen bond donor or acceptor motifs, or ionic
motifs such as amines that are protonated in the GI, or acids that
are deprotonated. Such modifications will increase the
hydrophilicity of the core or linker and help prevent hydrophobic
collapse. Furthermore, such modifications will also contribute to
the impermeability of the resulting compounds by increasing
tPSA.
[0225] Specific examples of NHE-binding small molecules modified
consistent with the principles detailed above are illustrated
below. These moieties display functional groups that facilitate
their appendage to "Z" (e.g., a core group, Core, or linking group,
L). These functional groups can include electrophiles, which can
react with nucleophilic cores or linkers, and nucleophiles, which
can react with electrophilic cores or linkers. Small molecule NHE
binding compounds may be similarly derivatized with, for example,
boronic acid groups which can then react with appropriate cores or
linkers via palladium mediated cross-coupling reactions. The NHE
binding compound may also contain olefins which can then react with
appropriate cores or linkers via olefin metathesis chemistry, or
alkynes or azides which can then react with appropriate cores or
linkers via [2+3] cycloaddition. One skilled in the art may
consider a variety of functional groups that will allow the facile
and specific attachment of an NHE-binding small molecule to a
desired core or linker. Exemplary functionalized derivatives of
NHEs include but are not limited to the following:
##STR00077##
[0226] wherein the variables in the above-noted structures (e.g.,
R, etc.) are as defined in U.S. Pat. No. 6,399,824, the entire
contents of which are incorporated herein by reference for all
relevant and consistent purposes.
##STR00078##
[0227] wherein the variables in the above-noted structures (e.g.,
R.sub.7-9, etc.) are as defined in U.S. Pat. No. 6,911,453, the
entire contents of which (and in particular the text of columns 1-4
therein) are incorporated herein by reference for all relevant and
consistent purposes. See also Linz et al., Hypertension. 60:1560-7,
2012.
##STR00079##
[0228] wherein the variables in the above-noted structures (e.g.,
R.sub.7-9, etc.) are as defined in U.S. Patent Application No.
2005/0020612 and U.S. Pat. No. 6,911,453, the entire contents of
which (and in particular the text of columns 1-4 therein) are
incorporated herein by reference for all relevant and consistent
purposes.
[0229] It is to be noted that one skilled in the art can envision a
number of core or linker moieties that may be functionalized with
an appropriate electrophile or nucleophile. Shown below are a
series of such compounds selected based on several design
considerations, including solubility, steric effects, and their
ability to confer, or be consistent with, favorable
structure-activity relationships. In this regard it is to be
further noted, however, that the structures provided below, and
above, are for illustration purposes only, and therefore should not
be viewed in a limiting sense.
[0230] Exemplary electrophilic and nucleophilic linker moieties
include, but are not limited to, the linker moieties illustrated by
the following:
[0231] Nucleophilic Linkers (for Use with Electrophilic
NHE-Inhibitory Derivatives)
##STR00080##
[0232] Electrophilic Linkers (for Use with Nucleophilic
NHE-Inhibitory Derivatives)
##STR00081##
[0233] The linking moiety, L, in each of the described embodiments
(including embodiments in which a NHE-binding small molecule is
linked to a core such as an atom, another small molecule, a polymer
moiety, an oligomer moiety, or a non-repeating moiety) can be a
chemical linker, such as a bond or other moiety, for example,
comprising about 1 to about 200 atoms, or about 1 to about 100
atoms, or about 1 to about 50 atoms, that can be hydrophilic and/or
hydrophobic. In one embodiment, the linking moiety can be a polymer
moiety grafted onto a polymer backbone, for example, using living
free radical polymerization approaches known in the art. Preferred
L structures or moieties may also be selected from, for example,
oligoethylene glycol, oligopeptide, oligoethyleneimine,
oligotetramethylene glycol and oligocaprolactone.
[0234] As noted, the core moiety can be an atom, a small molecule,
an oligomer, a dendrimer or a polymer moiety, in each case having
one or more sites of attachment for L. For example, the core moiety
can be a non-repeating moiety (considered as a whole including
linking points to the compounds), selected for example from the
group consisting of alkyl, phenyl, aryl, alkenyl, alkynyl,
heterocyclic, amine, ether, sulfide, disulfide, hydrazine, and any
of the foregoing substituted with oxygen, sulfur, sulfonyl,
phosphonyl, hydroxyl, alkoxyl, amine, thiol, ether, carbonyl,
carboxyl, ester, amide, alkyl, alkenyl, alkynyl, aryl,
heterocyclic, and moieties comprising combinations thereof (in each
permutation). A non-repeating moiety can include repeating units
(e.g., methylene) within portions or segments thereof (e.g., within
an alkyl segment), without having discrete repeat units that
constitute the moiety as a whole (e.g., in the sense of a polymer
or oligomer).
[0235] Exemplary core moieties include but are not limited to the
core moieties illustrated in the Examples and ether moieties, ester
moieties, sulfide moieties, disulfide moieties, amine moieties,
aryl moieties, alkoxyl moieties, etc., such as, for example, the
following:
##STR00082## ##STR00083## ##STR00084## ##STR00085## ##STR00086##
##STR00087##
wherein the broken bonds (i.e., those having a wavy bond, , through
them) are points of connection to either an NHE binding compound or
a linker moiety displaying an NHE binding compound, where said
points of connection can be made using chemistries and functional
groups known to the art of medicinal chemistry; and further wherein
each p, q, r and s is an independently selected integer ranging
from about 0 to about 48, preferably from about 0 to about 36, or
from about 0 to about 24, or from about 0 to about 16. In some
instances, each p, q, r and s can be an independently selected
integer ranging from about 0 to 12. Additionally, R can be a
substituent moiety generally selected from halide, hydroxyl, amine,
thiol, ether, carbonyl, carboxyl, ester, amide, carbocyclic,
heterocyclic, and moieties comprising combinations thereof.
[0236] In another approach, the core moiety is a dendrimer, defined
as a repeatedly branched molecule (see, e.g., J. M. J. Frechet, D.
A. Tomalia, Dendrimers and Other Dendritic Polymers, John Wiley
& Sons, Ltd. NY, N.Y., 2001) and represented in FIG. 17.
[0237] In this approach, the NHE-binding small molecule is attached
through L to one, several or optionally all termini located at the
periphery of the dendrimer. In another approach, a dendrimer
building block named dendron, and illustrated above, is used as a
core, wherein the NHE binding group is attached to one, several or
optionally all termini located at the periphery of the dendron. The
number of generations herein is typically between about 0 and about
6, and preferably between about 0 and about 3. (Generation is
defined in, for example, J. M. J. Frechet, D. A. Tomalia,
Dendrimers and Other Dendritic Polymers, John Wiley & Sons,
Ltd. NY, N.Y.) Dendrimer and/or dendron structures are well known
in the art and include, for example, those shown in or illustrated
by: (i) J. M. J. Frechet, D. A. Tomalia, Dendrimers and Other
Dendritic Polymers, John Wiley & Sons, Ltd. NY, N.Y.; (ii)
George R Newkome, Charles N. Moorefield and Fritz Vogtle,
Dendrimers and Dendrons: Concepts, Syntheses, Applications, VCH
Verlagsgesellschaft Mbh; and, (iii) Boas, U., Christensen, J. B.,
Heegaard, P. M. H., Dendrimers in Medicine and Biotechnology: New
Molecular Tools, Springer, 2006.
[0238] In yet another approach, the core moiety may be a polymer
moiety or an oligomer moiety. The polymer or oligomer may, in each
case, be independently considered and comprise repeat units
consisting of a repeat moiety selected from alkyl (e.g.,
--CH.sub.2--), substituted alkyl (e.g., --CHR--, wherein, for
example, R is hydroxy), alkenyl, substituted alkenyl, alkynyl,
substituted alkynyl, phenyl, aryl, heterocyclic, amine, ether,
sulfide, disulfide, hydrazine, and any of the foregoing substituted
with oxygen, sulfur, sulfonyl, phosphonyl, hydroxyl, alkoxyl,
amine, thiol, ether, carbonyl, carboxyl, ester, amide, alkyl,
alkenyl, alkynyl, aryl, heterocyclic, as well as moieties
comprising combinations thereof. In still another approach, the
core moiety comprises repeat units resulting from the
polymerization of ethylenic monomers (e.g., such as those ethylenic
monomers listed elsewhere herein below).
[0239] Preferred polymers for polymeric moieties useful in
constructing substantially impermeable or substantially
systemically non-bioavailable NHE-binding compounds that are
multivalent, for use in the treatment various treatment methods
disclosed herein, can be prepared by any suitable technique, such
as by free radical polymerization, condensation polymerization,
addition polymerization, ring-opening polymerization, and/or can be
derived from naturally occurring polymers, such as saccharide
polymers. Further, in some embodiments, any of these polymer
moieties may be functionalized.
[0240] Examples of polysaccharides useful in preparation of such
compounds include but are not limited to materials from vegetable
or animal origin, including cellulose materials, hemicellulose,
alkyl cellulose, hydroxyalkyl cellulose, carboxymethylcellulose,
sulfoethylcellulose, starch, xylan, amylopectine, chondroitin,
hyarulonate, heparin, guar, xanthan, mannan, galactomannan, chitin,
and/or chitosan. More preferred, in at least some instances, are
polymer moieties that do not degrade, or that do not degrade
significantly, under the physiological conditions of the GI tract
(such as, for example, carboxymethylcellulose, chitosan, and
sulfoethylcellulose).
[0241] When free radical polymerization is used, the polymer moiety
can be prepared from various classes of monomers including, for
example, acrylic, methacrylic, styrenic, vinylic, and dienic, whose
typical examples are given thereafter: styrene, substituted
styrene, alkyl acrylate, substituted alkyl acrylate, alkyl
methacrylate, substituted alkyl methacrylate, acrylonitrile,
methacrylonitrile, acrylamide, methacrylamide, N-alkylacrylamide,
N-alkylmethacrylamide, N,N-dialkylacrylamide,
N,N-dialkylmethacrylamide, isoprene, butadiene, ethylene, vinyl
acetate, and combinations thereof. Functionalized versions of these
monomers may also be used and any of these monomers may be used
with other monomers as co-monomers. For example, specific monomers
or co-monomers that may be used in this disclosure include methyl
methacrylate, ethyl methacrylate, propyl methacrylate (all
isomers), butyl methacrylate (all isomers), 2-ethylhexyl
methacrylate, isobornyl methacrylate, methacrylic acid, benzyl
methacrylate, phenyl methacrylate, methacrylonitrile,
.alpha.-methylstyrene, methyl acrylate, ethyl acrylate, propyl
acrylate (all isomers), butyl acrylate (all isomers), 2-ethylhexyl
acrylate, isobornyl acrylate, acrylic acid, benzyl acrylate, phenyl
acrylate, acrylonitrile, styrene, glycidyl methacrylate,
2-hydroxyethyl methacrylate, hydroxypropyl methacrylate (all
isomers), hydroxybutyl methacrylate (all isomers),
N,N-dimethylaminoethyl methacrylate, N,N-diethylaminoethyl
methacrylate, triethyleneglycol methacrylate, itaconic anhydride,
itaconic acid, glycidyl acrylate, 2-hydroxyethyl acrylate,
hydroxypropyl acrylate (all isomers), hydroxybutyl acrylate (all
isomers), N,N-dimethylaminoethyl acrylate, N,N-diethylaminoethyl
acrylate, triethyleneglycol acrylate, methacrylamide,
N-methylacrylamide, N,N-dimethylacrylamide,
N-tert-butylmethacrylamide, N-n-butylmethacrylamide,
N-methylolmethacrylamide, N-ethylolmethacrylamide,
N-tert-butylacrylamide, N--N-butylacrylamide, N-methylolacrylamide,
N-ethylolacrylamide, 4-acryloylmorpholine, vinyl benzoic acid (all
isomers), diethylaminostyrene (all isomers), a-methylvinyl benzoic
acid (all isomers), diethylamino .alpha.-methylstyrene (all
isomers), p-vinylbenzene sulfonic acid, p-vinylbenzene sulfonic
sodium salt, alkoxy and alkyl silane functional monomers, maleic
anhydride, N-phenylmaleimide, N-butylmaleimide, butadiene,
isoprene, chloroprene, ethylene, vinyl acetate, vinylformamide,
allylamine, vinylpyridines (all isomers), fluorinated acrylate,
methacrylates, and combinations thereof. Main chain heteroatom
polymer moieties can also be used, including polyethyleneimine and
polyethers such as polyethylene oxide and polypropylene oxide, as
well as copolymers thereof.
[0242] In one particular embodiment, the polymer to which the
NHE-binding small molecule, NHE, is attached or otherwise a part of
is a polyol (e.g., a polymer having a repeat unit of, for example,
a hydroxyl-substituted alkyl, such as --CH(OH)--). Polyols, such as
mono- and disaccharides, with or without reducing or reducible end
groups thereon, may be good candidates, for example, for installing
additional functionality that could render the compound
substantially impermeable.
[0243] In one particular embodiment, the NHE-binding small
molecule, NHE, is attached at one or both ends of the polymer
chain. More specifically, in yet another alternative approach to
the polyvalent embodiment of the present disclosure, a
macromolecule (e.g., a polymer or oligomer) having one of the
following exemplary structures may be designed and constructed as
described herein:
##STR00088## ##STR00089## ##STR00090## ##STR00091##
##STR00092##
[0244] It is to be further noted that the repeat moiety in Formulas
(XIIA) or (XIIB) generally encompasses repeating units of polymers
and copolymers produced by methods referred to herein above.
[0245] It is to be noted that the various properties of the
oligomers and polymers that form the core moiety as disclosed
herein above may be optimized for a given use or application using
experimental means and principles generally known in the art. For
example, the overall molecular weight of the compounds or
structures presented herein above may be selected so as to achieve
non-absorbability, inhibition persistence and/or potency.
[0246] Additionally, with respect to those polymeric embodiments
that encompass or include the compounds generally represented by
the structure of Formula (I) herein, and/or those disclosed for
example in the many patents and patent applications cited herein
(see, e.g., U.S. Pat. Nos. 5,866,610; 6,399,824; 6,911,453;
6,703,405; 6,005,010; 6,887,870; 6,737,423; 7,326,705; 55,824,691
(WO94/026709); U.S. Pat. No. 6,399,824 (WO02/024637); US
2004/0339001 (WO02/020496); US 2005/0020612 (WO03/055490);
WO01/072742; CA 2387529 (WO01021582); CA 02241531 (WO97/024113); US
2005/0113396 (WO03/051866); US2005/0020612; US2005/0054705;
US2008/0194621; US2007/0225323; US2004/0039001; US2004/0224965;
US2005/0113396; US2007/0135383; US2007/0135385; US2005/0244367;
US2007/0270414; and CA 2177007 (EP0744397), the entire contents of
which are incorporated herein by reference for all relevant and
consistent purposes), such as those wherein these compounds or
structures are pendants off of a polymeric backbone or chain, the
composition of the polymeric backbone or chain, as well as the
overall size or molecular weight of the polymer, and/or the number
of pendant molecules present thereon, may be selected according to
various principles known in the art in view of the intended
application or use.
[0247] With respect to the polymer composition of the NHE-binding
compound, it is to be noted that a number of polymers can be used
including, for example, synthetic and/or naturally occurring
aliphatic, alicyclic, and/or aromatic polymers. In preferred
embodiments, the polymer moiety is stable under physiological
conditions of the GI tract. By "stable" it is meant that the
polymer moiety does not degrade or does not degrade significantly
or essentially does not degrade under the physiological conditions
of the GI tract. For instance, at least about 90%, preferably at
least about 95%, and more preferably at least about 98%, and even
more preferably at least about 99% of the polymer moiety remains
un-degraded or intact after at least about 5 hours, at least about
12 hours, at least about 18 hours, at least about 24 hours, or at
least about 48 hours of residence in a gastrointestinal tract.
Stability in a gastrointestinal tract can be evaluated using
gastrointestinal mimics, e.g., gastric mimics or intestinal mimics
of the small intestine, which approximately model the physiological
conditions at one or more locations therein.
[0248] Polymer moieties detailed herein for use as the core moiety
can be hydrophobic, hydrophilic, amphiphilic, uncharged or
non-ionic, negatively or positively charged, or a combination
thereof. Additionally, the polymer architecture of the polymer
moiety can be linear, grafted, comb, block, star and/or dendritic,
preferably selected to produce desired solubility and/or stability
characteristics as described above.
[0249] Additionally or alternatively, modifications may be made to
NHE-binding small molecules that increase tPSA, thus contributing
to the impermeability of the resulting compounds. Such
modifications preferably include addition of di-anions, such as
phosphonates, malonates, sulfonates and the like, and polyols such
as carbohydrates and the like. Exemplary derivatives of NHEs with
increased tPSA include but are not limited to the following:
##STR00093## ##STR00094## ##STR00095##
[0250] (ii). Exemplary Embodiments
[0251] In one or more particularly preferred embodiments of the
present disclosure, the "NHE-Z" molecule is polyvalent; that is,
the molecule contains two or more moieties that effectively acts to
bind to and/or modulate NHE3 and also inhibit phosphate transport
in the GI tract or kidneys. In such embodiments, the NHE-Z molecule
may be selected, for example, from one of the following Formulas
(IV), (V), (VI) or (VII):
##STR00096##
[0252] wherein: each R.sub.1, R.sub.2, R.sub.3, R.sub.5 and R.sub.9
are independently selected from H, halogen, --NR.sub.7(CO)R.sub.8,
--(CO)NR.sub.7R.sub.8, --SO.sub.2--NR.sub.7R.sub.8,
--NR.sub.7SO.sub.2R.sub.8, --NR.sub.7R.sub.8, --OR.sub.7,
--SR.sub.7, --O(CO)NR.sub.7R.sub.8, --NR.sub.7(CO)OR.sub.8, and
--NR.sub.7SO.sub.2NR.sub.8, where R.sub.7 and R.sub.8 are
independently selected from H or L, provided at least one is L,
wherein L is selected from the group consisting of substituted or
unsubstituted hydrocarbyl, heterohydrocarbyl, polyalkylene glycol
and polyols, and further wherein L links the repeat unit to at
least one other repeat unit and/or at least one other Core moiety
independently selected from substituted or unsubstituted
hydrocarbyl, heterohydrocarbyl, polyalkylene glycol, polyols,
polyamines, or polyacrylamides, of the polyvalent compound; R.sub.4
is selected from H, C.sub.1-C.sub.7 alkyl or L, where L is as
described above; R.sub.6 is absent or selected from H and
C.sub.1-C.sub.7 alkyl; and, Ar1 and Ar2 independently represent an
aromatic ring, or alternatively a heteroaromatic ring wherein one
or more of the carbon atoms therein is replaced with a N, O or S
atom;
##STR00097##
[0253] wherein: each R.sub.1, R.sub.2, R.sub.3, and R.sub.5 are
optionally linked to the ring Ar1 by a heterocyclic linker, and
further are independently selected from H, --NR.sub.7(CO)R.sub.8,
--(CO)NR.sub.7R.sub.8, --SO.sub.2--NR.sub.7R.sub.8,
--NR.sub.7SO.sub.2R.sub.8, --NR.sub.7R.sub.8, --OR.sub.7,
--SR.sub.7, --O(CO)NR.sub.7R.sub.8, --NR.sub.7(CO)OR.sub.8, and
--NR.sub.7SO.sub.2NR.sub.8, where R.sub.7 and R.sub.8 are
independently selected from H or L, provided at least one is L,
wherein L is selected from the group consisting of substituted or
unsubstituted hydrocarbyl, heterohydrocarbyl, polyalkylene glycol
and polyols, and further wherein L links the repeat unit to at
least one other repeat unit and/or at least one other Core moiety
independently selected from substituted or unsubstituted
hydrocarbyl, heterohydrocarbyl, polyalkylene glycol, polyols,
polyamines, or polyacrylamides, of the polyvalent compound; R.sub.4
and R.sub.12 are independently selected from H or L, where L is as
defined above; R.sub.10 and R.sub.11, when presented, are
independently selected from H and C.sub.1-C.sub.7 alkyl; and, Ar1
and Ar2 independently represent an aromatic ring, or alternatively
a heteroaromatic ring wherein one or more of the carbon atoms
therein is replaced with a N, O or S atom;
##STR00098##
[0254] wherein: each X is a halogen atom, which may be the same or
different; R.sub.1 is selected from --SO.sub.2--NR.sub.7R.sub.8,
--NR.sub.7(CO)R.sub.8, --(CO)NR.sub.7R.sub.8,
--NR.sub.7SO.sub.2R.sub.8, --NR.sub.7R.sub.8, --OR.sub.7,
--SR.sub.7, --O(CO)NR.sub.7R.sub.8, --NR.sub.7(CO)OR.sub.8, and
--NR.sub.7SO.sub.2NR.sub.8, where R.sub.7 and R.sub.8 are
independently selected from H or L, provided at least one is L,
wherein L is selected from the group consisting of substituted or
unsubstituted hydrocarbyl, heterohydrocarbyl, polyalkylene glycol
and polyols, and further wherein L links the repeat unit to at
least one other repeat unit and/or at least one other Core moiety
independently selected from substituted or unsubstituted
hydrocarbyl, heterohydrocarbyl, polyalkylene glycol, polyols,
polyamines, or polyacrylamides, of the polyvalent compound; R.sub.3
is selected from H or L, where L is as described above; R.sub.13 is
selected from substituted or unsubstituted C.sub.1-C.sub.5 alkyl;
R.sub.2 and R.sub.12 are independently selected from H or L,
wherein L is as described above; R.sub.10 and R.sub.11, when
present, are independently selected from H and C.sub.1-C.sub.7
alkyl; Ar1 represents an aromatic ring, or alternatively a
heteroaromatic ring wherein one or more of the carbon atoms therein
is replaced with a N, O or S atom; and Ar2 represents an aromatic
ring, or alternatively a heteroaromatic ring wherein one or more of
the carbon atoms therein is replaced with a N, O or S atom.
[0255] In one particular embodiment for the structure of Formula
(V), one of R.sub.1, R.sub.2 and R.sub.3 is linked to the ring Ar1,
and/or R.sub.5 is linked to the ring Ar2, by a heterocyclic linker
having the structure:
##STR00099##
[0256] wherein R represents R.sub.1, R.sub.2, R.sub.3, or R.sub.5
bound thereto.
[0257] In one particular embodiment, the NHE-binding small molecule
has the structure of Formula (IV):
##STR00100##
[0258] or a stereoisomer, prodrug or pharmaceutically acceptable
salt thereof, wherein: each R.sub.1, R.sub.2, R.sub.3, R.sub.5 and
R.sub.9 are independently selected from H, halogen,
--NR.sub.7(CO)R.sub.8, --(CO)NR.sub.7R.sub.8,
--SO.sub.2--NR.sub.7R.sub.8, --NR.sub.7SO.sub.2R.sub.8,
--NR.sub.7R.sub.8, --OR.sub.7, --SR.sub.7, --O(CO)NR.sub.7R.sub.8,
--NR.sub.7(CO)OR.sub.8, and --NR.sub.7SO.sub.2NR.sub.8, where
R.sub.7 and R.sub.8 are independently selected from H or a bond
linking the NHE-binding small molecule to L, provided at least one
is a bond linking the NHE-binding small molecule to L; R.sub.4 is
selected from H, C.sub.1-C.sub.7 alkyl, or a bond linking the
NHE-binding small molecule to L; R.sub.6 is absent or selected from
H and C.sub.1-C.sub.7 alkyl; and Ar1 and Ar2 independently
represent an aromatic ring or a heteroaromatic ring.
[0259] In further particular embodiments of the above embodiment,
the NHE-binding small molecule has the following structure:
##STR00101##
[0260] or a stereoisomer, prodrug or pharmaceutically acceptable
salt thereof, wherein: each R.sub.1, R.sub.2 and R.sub.3 are
independently selected from H, halogen, --NR.sub.7(CO)R.sub.8,
--(CO)NR.sub.7R.sub.8, --SO.sub.2--NR.sub.7R.sub.8,
--NR.sub.7SO.sub.2R.sub.8, --NR.sub.7R.sub.8, --OR.sub.7,
--SR.sub.7, --O(CO)NR.sub.7R.sub.8, --NR.sub.7(CO)OR.sub.8, and
--NR.sub.7SO.sub.2NR.sub.8, where R.sub.7 and R.sub.8 are
independently selected from H or a bond linking the NHE-binding
small molecule to L, provided at least one is a bond linking the
NHE-binding small molecule to L.
[0261] In one embodiment, the compound has the structure of Formula
(X):
##STR00102##
[0262] In further particular embodiments of the above embodiment,
the NHE-binding small molecule has one of the following
structures:
##STR00103##
[0263] or a stereoisomer, prodrug or pharmaceutically acceptable
salt thereof.
[0264] In further particular embodiments of the above embodiment, L
is a polyalkylene glycol linker, such as a polyethylene glycol
linker.
[0265] In further particular embodiments of the above embodiment, n
is 2.
[0266] In further particular embodiments of the above embodiment,
the Core has the following structure:
##STR00104##
[0267] wherein: X is selected from the group consisting of a bond,
--O--, --NH--, --S--, C.sub.1-6alkylene, --NHC(.dbd.O)--,
--C(.dbd.O)NH--, --NHC(.dbd.O)NH--, --SO.sub.2NH--, and
--NHSO.sub.2--; Y is selected from the group consisting of a bond,
optionally substituted C.sub.1-8alkylene, optionally substituted
aryl, optionally substituted heteroaryl, a polyethylene glycol
linker, --(CH.sub.2).sub.1-6O(CH.sub.2).sub.1-6-- and
--(CH.sub.2).sub.1-6NY(CH.sub.2).sub.1-6--; and Y.sub.1 is selected
from the group consisting of hydrogen, optionally substituted
C.sub.1-8alkyl, optionally substituted aryl or optionally
substituted heteroaryl.
[0268] In further particular embodiments of the above embodiment,
the Core is selected from the group consisting of:
##STR00105##
H. General Structure of Additional Exemplary Compounds
[0269] In one embodiment, the compounds of the present disclosure
may be generally represented by Formula (I-H):
##STR00106##
[0270] or a stereoisomer, prodrug or pharmaceutically acceptable
salt thereof, wherein: (i) NHE represents a NHE-binding and/or
modulating small molecule moiety as set forth below, (ii) n is an
integer of 2 or more, (iii) Core is a Core moiety having two or
more sites thereon for attachment to two or more NHE-binding small
molecule moieties, and (iv) L is a bond or linker connecting the
Core moiety to the two or more NHE-binding small molecule moieties,
the resulting NHE-binding compound (i.e., a compound of Formula
(I)) possessing overall physicochemical properties that render it
substantially impermeable or substantially systemically
non-bioavailable. The Core moiety may be bound to essentially any
position on, or within, the NHE-binding small molecule moiety,
provided that the installation thereof does not significantly
adversely impact NHE-binding activity.
[0271] It is to be noted that, in the many structures illustrated
herein, all of the various linkages or bonds will not be shown in
every instance. For example, in one or more of the structures
illustrated above, a bond or connection between the NHE-binding
small molecule moiety and the Core moiety is not always shown.
However, this should not be viewed in a limiting sense. Rather, it
is to be understood that the NHE-binding small molecule moiety is
bound or connected in some way (e.g., by a bond or linker of some
kind) to the Core moiety, such that the resulting NHE-binding
compound is suitable for use (i.e., substantially impermeable or
substantially systemically non-bioavailable in the GI tract).
[0272] NHE-binding small molecule moieties suitable for use (i.e.,
suitable for modification or functionalization in accordance with
the present disclosure) in the preparation of the substantially
impermeable or substantially systemically non-bioavailable
NHE-binding compounds of the present disclosure are disclosed in WO
2010/025856, the entire contents of which are incorporated herein
by reference for all relevant and consistent purposes, and have the
following structure of Formula (X-H):
##STR00107##
[0273] The variables in the structure are defined in WO
2010/025856, the details of which are incorporated herein by
reference.
[0274] In more specific embodiments, the NHE-binding small molecule
moiety has the following structure of Formula (XI-H):
##STR00108##
wherein: B is selected from the group consisting of aryl and
heterocyclyl; each R.sub.5 is independently selected from the group
consisting of hydrogen, halogen, optionally substituted
C.sub.1-4alkyl, optionally substituted C.sub.1-4alkoxy, optionally
substituted C.sub.1-4thioalkyl, optionally substituted
heterocyclyl, optionally substituted heterocyclylalkyl, optionally
substituted aryl, optionally substituted heteroaryl, hydroxyl, oxo,
cyano, nitro, --NR.sub.7R.sub.8, --NR.sub.7C(.dbd.O)R.sub.8,
--NR.sub.7C(.dbd.O)OR.sub.8, --NR.sub.7C(.dbd.O)NR.sub.8R.sub.9,
--NR.sub.7SO.sub.2R.sub.8, --NR.sub.7S(O).sub.2NR.sub.8R.sub.9,
--C(.dbd.O)OR.sub.7, --C(.dbd.O)R.sub.7,
--C(.dbd.O)NR.sub.7R.sub.8, --S(O).sub.1-2R.sub.7, and
--SO.sub.2NR.sub.7R.sub.8, wherein R.sub.7, R.sub.8, and R.sub.9
are independently selected from the group consisting of hydrogen,
C.sub.1-4alkyl, or a bond linking the NHE-binding small molecule
moiety to L, provided at least one is a bond linking the
NHE-binding small molecule moiety to L; R.sub.3 and R.sub.4 are
independently selected from the group consisting of hydrogen,
optionally substituted C.sub.1-4alkyl, optionally substituted
cycloalkyl, optionally substituted cycloalkylalkyl, optionally
substituted aryl, optionally substituted aralkyl, optionally
substituted heterocyclyl and optionally substituted heteroaryl; or
R.sub.3 and R.sub.4 form together with the nitrogen to which they
are bonded an optionally substituted 4-8 membered heterocyclyl; and
each R.sub.1 is independently selected from the group consisting of
hydrogen, halogen, optionally substituted C.sub.1-6alkyl and
optionally substituted C.sub.1-6alkoxy.
[0275] In yet further more specific embodiments, the NHE-binding
small molecule moiety has the following structure of Formula
(XII-H):
##STR00109##
wherein: each R.sub.3 and R.sub.4 are independently selected from
the group consisting of hydrogen and optionally substituted
C.sub.1-4alkyl, or R.sub.3 and R.sub.4, taken together with the
nitrogen to which they are bonded, form an optionally substituted
4-8 membered heterocyclyl; each R.sub.1 is independently selected
from the group consisting of hydrogen, halogen, C.sub.1-6alkyl, and
C.sub.1-6haloalkyl; and R.sub.5 is selected from the group
consisting of --SO.sub.2--NR.sub.7-- and --NHC(.dbd.O)NH--, wherein
R.sub.7 is hydrogen or C.sub.1-4alkyl.
[0276] In various alternative embodiments, the NHE-binding small
molecule moiety may be rendered substantially impermeable or
substantially systemically non-bioavailable by forming a polymeric
structure from multiple NHE-binding small molecule moieties, which
may be the same or different, connected or bound by a series of
linkers, L, which also may be the same or different, the compound
having for example the structure of Formula (II-H):
##STR00110##
[0277] wherein: NHE is as defined above; L is a bond or linker, as
further defined elsewhere herein; and m is 0 or an integer of 1 or
more. In this embodiment, the physicochemical properties, and in
particular the molecular weight or polar surface area, of the
NHE-binding small molecule moiety is modified (e.g., increased) by
having a series of NHE-binding small molecule moieties linked
together, in order to render them substantially impermeable or
substantially systemically non-bioavailable.
[0278] In yet additional alternative embodiments, the polyvalent
NHE-binding compound may be in oligomeric or polymeric form,
wherein a backbone is bound (by means of a linker, for example) to
multiple NHE-binding small molecule moieties. Such compounds may
have, for example, the structures of Formulas (IIIA-H) or
(IIIB-H):
##STR00111##
[0279] wherein: NHE is as defined above; L is a bond or linker, as
further defined elsewhere herein; and n is a non-zero integer
(i.e., an integer of 1 or more). It is to be noted that the repeat
unit in Formulas (IIIA-H) and (IIIB-H) generally encompasses
repeating units of various polymeric embodiments, including linear,
branched and dendritic structures, which may optionally be produced
by methods referred to herein. In each polymeric, or more general
polyvalent, embodiment, it is to be noted that each repeat unit may
be the same or different, and may or may not be linked to the
NHE-binding small molecule moiety by a linker, which in turn may be
the same or different when present. In this regard it is to be
noted that as used herein, "polyvalent" refers to a molecule that
has multiple (e.g., 2, 4, 6, 8, 10 or more) NHE-binding small
molecule moieties therein.
[0280] In the foregoing polyvalent embodiments, L may be a
polyalkylene glycol linker, such as a polyethylene glycol linker;
and/or the Core may have the following structure:
##STR00112##
[0281] wherein: X is selected from the group consisting of a bond,
--O--, --NH--, --S--, C.sub.1-6alkylene, --NHC(.dbd.O)--,
--C(.dbd.O)NH--, --NHC(.dbd.O)NH--, --SO.sub.2NH--, and
--NHSO.sub.2--; Y is selected from the group consisting of a bond,
optionally substituted C.sub.1-8alkylene, optionally substituted
aryl, optionally substituted heteroaryl, a polyethylene glycol
linker, --(CH.sub.2).sub.1-6O(CH.sub.2).sub.1-6-- and
--(CH.sub.2).sub.1-6NY.sub.1(CH.sub.2).sub.1-6--; and Y.sub.1 is
selected from the group consisting of hydrogen, optionally
substituted C.sub.1-8alkyl, optionally substituted aryl or
optionally substituted heteroaryl. For example, in more specific
embodiments, the Core may be selected, for example, from the group
consisting of:
##STR00113##
[0282] In other more specific embodiments, the Core may be
selected, for example, from the group consisting of
##STR00114## ##STR00115##
[0283] The above noted embodiments are further illustrated herein
below. For example, the first representation below of an exemplary
oligomer compound, wherein the various parts of the compound are
identified, is intended to provide a broad context for the
disclosure provided herein. It is to be noted that while each
NHE-binding small molecule moiety in the structure below is the
same, it is within the scope of this disclosure that each is
independently selected and may be the same or different. In the
illustration below, the linker moiety is a polyethylene glycol
(PEG) motif. PEG derivatives are advantageous due in part to their
aqueous solubility, which may help avoid hydrophobic collapse (the
intramolecular interaction of hydrophobic motifs that can occur
when a hydrophobic molecule is exposed to an aqueous environment
(see, e.g., Wiley, R. A.; Rich, D. H. Medical Research Reviews
1993, 13(3), 327-384). The core moiety illustrated below is also
advantageous because it provides some rigidity to the molecule,
allowing an increase in distance between the NHE-binding small
molecule moieties while minimally increasing rotational degrees of
freedom.
##STR00116##
[0284] In an alternative embodiment, wherein m=0, the structure may
be, for example:
##STR00117##
[0285] Within the polyvalent compounds utilized for treatments
according to the present disclosure, n and m (when m is not zero)
may be independently selected from the range of from about 1 to
about 10, more preferably from about 1 to about 5, and even more
preferably from about 1 to about 2. In alternative embodiments,
however, n and m may be independently selected from the range of
from about 1 to about 500, preferably from about 1 to about 300,
more preferably from about 1 to about 100, and most preferably from
about 1 to about 50. In these or other particular embodiments, E, n
and m may be within the range of from about 1 to about 50, or from
about 1 to about 20.
[0286] In designing and making the substantially impermeable or
substantially systemically non-bioavailable NHE-binding compounds
that may be utilized for the treatments detailed in the instant
disclosure, it may in some cases be advantageous to first determine
a likely point of attachment on a NHE-binding small molecule
moiety, where a core or linker might be installed or attached
before making a series of candidate multivalent or polyvalent
compounds. This may be done by one skilled in the art via known
methods by systematically installing functional groups, or
functional groups displaying a fragment of the desired core or
linker, onto various positions of the NHE-binding small molecule
moiety and then testing these adducts to determine whether the
modified compound still retains desired biological properties
(e.g., NHE-binding activity). An understanding of the SAR of the
compound also allows the design of cores and/or linkers that
contribute positively to the activity of the resulting
compounds.
[0287] Another aspect to be considered in the design of cores and
linkers is the limiting or preventing of hydrophobic collapse.
Compounds with extended hydrocarbon functionalities may collapse
upon themselves in an intramolecular fashion, causing an increased
enthalpic barrier for interaction with the desired biological
target. Accordingly, when designing cores and linkers, these are
preferably designed to be resistant to hydrophobic collapse. For
example, conformational constraints such as rigid monocyclic,
bicyclic or polycyclic rings can be installed in a core or linker
to increase the rigidity of the structure. Unsaturated bonds, such
as alkenes and alkynes, may also or alternatively be installed.
Such modifications may ensure the NHE-binding compound is
accessible for productive binding with its target. Furthermore, the
hydrophilicity of the linkers may be improved by adding hydrogen
bond donor or acceptor motifs, or ionic motifs such as amines that
are protonated in the GI, or acids that are deprotonated. Such
modifications will increase the hydrophilicity of the core or
linker and help prevent hydrophobic collapse. Furthermore, such
modifications will also contribute to the impermeability of the
resulting compounds by increasing tPSA.
[0288] One skilled in the art may consider a variety of functional
groups that will allow the facile and specific attachment of a
NHE-binding small molecule moiety to a core or linker. These
functional groups can include electrophiles, which can react with
nucleophilic cores or linkers, and nucleophiles, which can react
with electrophilic cores or linkers. NHE-binding small molecule
moieties may be similarly derivatized with, for example, boronic
acid groups which can then react with appropriate cores or linkers
via palladium mediated cross-coupling reactions. The NHE-binding
small molecule moiety may also contain olefins which can then react
with appropriate cores or linkers via olefin metathesis chemistry,
or alkynes or azides which can then react with appropriate cores or
linkers via [2+3] cycloaddition.
[0289] It is to be noted that one skilled in the art can envision a
number of core or linker moieties that may be functionalized with
an appropriate electrophile or nucleophile. Shown below are a
series of such compounds selected based on several design
considerations, including solubility, steric effects, and their
ability to confer, or be consistent with, favorable
structure-activity relationships. In this regard it is to be
further noted, however, that the structures provided below, and
above, are for illustration purposes only, and therefore should not
be viewed in a limiting sense.
[0290] Exemplary electrophilic and nucleophilic linker moieties
include, but are not limited to, the linker moieties illustrated in
the following:
[0291] Nucleophilic Linkers (for Use with Electrophilic NHEs)
##STR00118##
[0292] Electrophilic Linkers (for Use with Nucleophilic NHEs)
##STR00119##
[0293] The linking moiety, L, in each of the described embodiments
(including embodiments in which a NHE-binding small molecule moiety
is linked to a Core such as an atom, another small molecule, a
polymer moiety, an oligomer moiety, or a non-repeating moiety) can
be a chemical linker, such as a bond or other moiety, for example,
comprising about 1 to about 200 atoms, or about 1 to about 100
atoms, or about 1 to about 50 atoms, that can be hydrophilic and/or
hydrophobic. In one embodiment, the linking moiety can be a polymer
moiety grafted onto a polymer backbone, for example, using living
free radical polymerization approaches known in the art. Preferred
L structures or moieties may also be selected from, for example,
oligoethylene glycol, oligopeptide, oligoethyleneimine,
oligotetramethylene glycol and oligocaprolactone.
[0294] As noted, the core moiety can be an atom, a small molecule,
an oligomer, a dendrimer or a polymer moiety, in each case having
one or more sites of attachment for L. For example, the core moiety
can be a non-repeating moiety (considered as a whole including
linking points to the NHE-binding small molecule moieties),
selected for example from the group consisting of alkyl, phenyl,
aryl, alkenyl, alkynyl, heterocyclic, amine, ether, sulfide,
disulfide, hydrazine, and any of the foregoing substituted with
oxygen, sulfur, sulfonyl, phosphonyl, hydroxyl, alkoxyl, amine,
thiol, ether, carbonyl, carboxyl, ester, amide, alkyl, alkenyl,
alkynyl, aryl, heterocyclic, and moieties comprising combinations
thereof (in each permutation). A non-repeating moiety can include
repeating units (e.g., methylene) within portions or segments
thereof (e.g., within an alkyl segment), without having discrete
repeat units that constitute the moiety as a whole (e.g., in the
sense of a polymer or oligomer).
[0295] Exemplary core moieties include but are not limited to the
core moieties illustrated in the Examples and ether moieties, ester
moieties, sulfide moieties, disulfide moieties, amine moieties,
aryl moieties, alkoxyl moieties, etc., such as, for example, the
following:
##STR00120## ##STR00121## ##STR00122## ##STR00123## ##STR00124##
##STR00125##
[0296] wherein the broken bonds (i.e., those having a wavy bond, ,
through them) are points of connection to either a NHE-binding
small molecule moiety or a linker moiety displaying a NHE-binding
small molecule moiety, where said points of connection can be made
using chemistries and functional groups known to the art of
medicinal chemistry; and further wherein each p, q, r and s is an
independently selected integer ranging from about 0 to about 48,
preferably from about 0 to about 36, or from about 0 to about 24,
or from about 0 to about 16. In some instances, each p, q, r and s
can be an independently selected integer ranging from about 0 to
12. Additionally, R can be a substituent moiety generally selected
from halide, hydroxyl, amine, thiol, ether, carbonyl, carboxyl,
ester, amide, carbocyclic, heterocyclic, and moieties comprising
combinations thereof.
[0297] In another approach, the core moiety may be a dendrimer,
defined as a repeatedly branched molecule (see, e.g., J. M. J.
Frechet, D. A. Tomalia, Dendrimers and Other Dendritic Polymers,
John Wiley & Sons, Ltd. NY, N.Y., 2001) and schematically
represented In FIG. 17.
[0298] In this approach, the NHE-binding small molecule moiety is
attached through L to one, several or optionally all termini
located at the periphery of the dendrimer. In another approach, a
dendrimer building block named dendron, and illustrated above, is
used as a core, wherein the NHE-binding small molecule moiety is
attached to one, several or optionally all termini located at the
periphery of the dendron. The number of generations herein is
typically between about 0 and about 6, and preferably between about
0 and about 3. (Generation is defined in, for example, J. M. J.
Frechet, D. A. Tomalia, Dendrimers and Other Dendritic Polymers,
John Wiley & Sons, Ltd. NY, N.Y..) Dendrimer and/or dendron
structures are well known in the art and include, for example,
those shown in or illustrated by: (i) J. M. J. Frechet, D. A.
Tomalia, Dendrimers and Other Dendritic Polymers, John Wiley &
Sons, Ltd. NY, N.Y.; (ii) George R Newkome, Charles N. Moorefield
and Fritz Vogtle, Dendrimers and Dendrons: Concepts, Syntheses,
Applications, VCH Verlagsgesellschaft Mbh; and, (iii) Boas, U.,
Christensen, J. B., Heegaard, P. M. H., Dendrimers in Medicine and
Biotechnology: New Molecular Tools, Springer, 2006.
[0299] In yet another approach, the core moiety may be a polymer
moiety or an oligomer moiety. The polymer or oligomer may, in each
case, be independently considered and comprise repeat units
consisting of a repeat moiety selected from alkyl (e.g.,
--CH.sub.2--), substituted alkyl (e.g., --CHR--, wherein, for
example, R is hydroxy), alkenyl, substituted alkenyl, alkynyl,
substituted alkynyl, phenyl, aryl, heterocyclic, amine, ether,
sulfide, disulfide, hydrazine, and any of the foregoing substituted
with oxygen, sulfur, sulfonyl, phosphonyl, hydroxyl, alkoxyl,
amine, thiol, ether, carbonyl, carboxyl, ester, amide, alkyl,
alkenyl, alkynyl, aryl, heterocyclic, as well as moieties
comprising combinations thereof. In still another approach, the
core moiety comprises repeat units resulting from the
polymerization of ethylenic monomers (e.g., such as those ethylenic
monomers listed elsewhere herein below).
[0300] Preferred polymers for polymeric moieties useful in
constructing substantially impermeable or substantially
systemically non-bioavailable NHE-binding compounds that are
multivalent, for use in the treatment various treatment methods
disclosed herein, can be prepared by any suitable technique, such
as by free radical polymerization, condensation polymerization,
addition polymerization, ring-opening polymerization, and/or can be
derived from naturally occurring polymers, such as saccharide
polymers. Further, in some embodiments, any of these polymer
moieties may be functionalized.
[0301] Examples of polysaccharides useful in preparation of such
compounds include but are not limited to materials from vegetable
or animal origin, including cellulose materials, hemicellulose,
alkyl cellulose, hydroxyalkyl cellulose, carboxymethylcellulose,
sulfoethylcellulose, starch, xylan, amylopectine, chondroitin,
hyarulonate, heparin, guar, xanthan, mannan, galactomannan, chitin,
and/or chitosan. More preferred, in at least some instances, are
polymer moieties that do not degrade, or that do not degrade
significantly, under the physiological conditions of the GI tract
(such as, for example, carboxymethylcellulose, chitosan, and
sulfoethylcellulose).
[0302] When free radical polymerization is used, the polymer moiety
can be prepared from various classes of monomers including, for
example, acrylic, methacrylic, styrenic, vinylic, and dienic, whose
typical examples are given thereafter: styrene, substituted
styrene, alkyl acrylate, substituted alkyl acrylate, alkyl
methacrylate, substituted alkyl methacrylate, acrylonitrile,
methacrylonitrile, acrylamide, methacrylamide, N-alkylacrylamide,
N-alkylmethacrylamide, N,N-dialkylacrylamide,
N,N-dialkylmethacrylamide, isoprene, butadiene, ethylene, vinyl
acetate, and combinations thereof. Functionalized versions of these
monomers may also be used and any of these monomers may be used
with other monomers as co-monomers. For example, specific monomers
or co-monomers that may be used in this disclosure include methyl
methacrylate, ethyl methacrylate, propyl methacrylate (all
isomers), butyl methacrylate (all isomers), 2-ethylhexyl
methacrylate, isobornyl methacrylate, methacrylic acid, benzyl
methacrylate, phenyl methacrylate, methacrylonitrile,
.alpha.-methylstyrene, methyl acrylate, ethyl acrylate, propyl
acrylate (all isomers), butyl acrylate (all isomers), 2-ethylhexyl
acrylate, isobornyl acrylate, acrylic acid, benzyl acrylate, phenyl
acrylate, acrylonitrile, styrene, glycidyl methacrylate,
2-hydroxyethyl methacrylate, hydroxypropyl methacrylate (all
isomers), hydroxybutyl methacrylate (all isomers),
N,N-dimethylaminoethyl methacrylate, N,N-diethylaminoethyl
methacrylate, triethyleneglycol methacrylate, itaconic anhydride,
itaconic acid, glycidyl acrylate, 2-hydroxyethyl acrylate,
hydroxypropyl acrylate (all isomers), hydroxybutyl acrylate (all
isomers), N,N-dimethylaminoethyl acrylate, N,N-diethylaminoethyl
acrylate, triethyleneglycol acrylate, methacrylamide,
N-methylacrylamide, N,N-dimethylacrylamide,
N-tert-butylmethacrylamide, N-n-butylmethacrylamide,
N-methylolmethacrylamide, N-ethylolmethacrylamide,
N-tert-butylacrylamide, N--N-butylacrylamide, N-methylolacrylamide,
N-ethylolacrylamide, 4-acryloylmorpholine, vinyl benzoic acid (all
isomers), diethylaminostyrene (all isomers), a-methylvinyl benzoic
acid (all isomers), diethylamino .alpha.-methylstyrene (all
isomers), p-vinylbenzene sulfonic acid, p-vinylbenzene sulfonic
sodium salt, alkoxy and alkyl silane functional monomers, maleic
anhydride, N-phenylmaleimide, N-butylmaleimide, butadiene,
isoprene, chloroprene, ethylene, vinyl acetate, vinylformamide,
allylamine, vinylpyridines (all isomers), fluorinated acrylate,
methacrylates, and combinations thereof. Main chain heteroatom
polymer moieties can also be used, including polyethyleneimine and
polyethers such as polyethylene oxide and polypropylene oxide, as
well as copolymers thereof.
[0303] In one particular embodiment, the polymer to which the
NHE-binding small molecule moiety is attached, or otherwise a part
of, is a polyol (e.g., a polymer having a repeat unit of, for
example, a hydroxyl-substituted alkyl, such as --CH(OH)--).
Polyols, such as mono- and disaccharides, with or without reducing
or reducible end groups thereon, may be good candidates, for
example, for installing additional functionality that could render
the compound substantially impermeable.
[0304] In one particular embodiment, the NHE-binding small molecule
moiety is attached at one or both ends of the polymer chain. More
specifically, in yet another alternative approach to the polyvalent
embodiment of the present disclosure, a macromolecule (e.g., a
polymer or oligomer) having one of the following exemplary
structures (wherein is a NHE-binding small molecule moiety) may be
designed and constructed as described herein:
##STR00126## ##STR00127##
I. General Structure of Additional Exemplary Compounds
[0305] In one embodiment, a compound is provided having the
structure of Formula (I-I):
##STR00128##
or a stereoisomer, prodrug or pharmaceutically acceptable salt
thereof, wherein: (a) NHE is a NHE-binding small molecule moiety
having the following structure of Formula (A-I):
##STR00129##
wherein: each R.sub.1, R.sub.2, R.sub.3, R.sub.5 and R.sub.9 are
independently selected from H, halogen, --NR.sub.7(CO)R.sub.8,
--(CO)NR.sub.7R.sub.8, --SO.sub.2--NR.sub.7R.sub.8,
--NR.sub.7SO.sub.2R.sub.8, --NR.sub.7R.sub.8, --OR.sub.7,
--SR.sub.7, --O(CO)NR.sub.7R.sub.8, --NR.sub.7(CO)OR.sub.8, and
--NR.sub.7SO.sub.2NR.sub.8, where R.sub.7 and R.sub.8 are
independently selected from H, C.sub.1-6alkyl, --C.sub.1-6alkyl-OH
or a bond linking the NHE-binding small molecule to L, provided at
least one is a bond linking the NHE-binding small molecule to L;
R.sub.4 is selected from H, C.sub.1-C.sub.7 alkyl, or a bond
linking the NHE-binding small molecule to L; R.sub.6 is absent or
selected from H and C.sub.1-C.sub.7 alkyl; and Ar1 and Ar2
independently represent an aromatic ring or a heteroaromatic ring;
(b) Core is a Core moiety having the following structure of Formula
(B-I):
##STR00130##
wherein: X is selected from C(X.sub.1), N and N(C.sub.1-6alkyl); X
is selected from hydrogen, optionally substituted alkyl,
--NX.sub.aX.sub.b, --NO.sub.2,
--NX.sub.c--C(.dbd.O)--NX.sub.c--X.sub.a,
--C(.dbd.O)NX.sub.c--X.sub.a, --NX.sub.c--C(.dbd.O)--X.sub.a,
--NX.sub.c--SO.sub.2--X.sub.a, --C(.dbd.O)--X.sub.a and --OX.sub.a;
each X.sub.a and X.sub.b are independently selected from hydrogen,
optionally substituted alkyl, optionally substituted cycloalkyl,
optionally substituted cycloalkylalkyl, optionally substituted
heterocyclyl, optionally substituted heterocyclylalkyl, optionally
substituted aryl, optionally substituted aralkyl, optionally
substituted heteroaryl and optionally substituted heteroarylalkyl;
Y is C.sub.1-6alkylene; Z is selected from
--NZ.sub.a--C(.dbd.O)--NZ.sub.a--, --C(.dbd.O)NZ.sub.a,
--NZ.sub.aC(.dbd.O)-- and heteroaryl when X is CX.sub.1; Z is
selected from --NZ.sub.a--C(.dbd.O)--NZ.sub.a--,
--NZ.sub.aC(.dbd.O)-- and heteroaryl when X is N or
N(C.sub.1-6alkyl); and each X.sub.c and Z.sub.a is independently
selected from hydrogen and C.sub.1-6alkyl; and (c) L is a bond or
linker connecting the Core moiety to the NHE-binding small molecule
moieties, the resulting NHE-binding compound (i.e., a compound of
Formula (I)) possessing overall physicochemical properties that
render it substantially impermeable or substantially systemically
non-bioavailable. The Core moiety may be bound to essentially any
position on, or within, the NHE-binding small molecule moiety,
provided that the installation thereof does not significantly
adversely impact activity.
[0306] In another embodiment, a compound is provided having the
structure of Formula (II-I):
##STR00131##
or a stereoisomer, prodrug or pharmaceutically acceptable salt
thereof, wherein: (a) NHE is a NHE-binding small molecule moiety
having the structure of Formula (A-I):
##STR00132##
wherein: each R.sub.1, R.sub.2, R.sub.3, R.sub.5 and R.sub.9 are
independently selected from H, halogen, --NR.sub.7(CO)R.sub.8,
--(CO)NR.sub.7R.sub.8, --SO.sub.2--NR.sub.7R.sub.8,
--NR.sub.7SO.sub.2R.sub.8, --NR.sub.7R.sub.8, --OR.sub.7,
--SR.sub.7, --O(CO)NR.sub.7R.sub.8, --NR.sub.7(CO)OR.sub.8, and
--NR.sub.7SO.sub.2NR.sub.8, where R.sub.7 and R.sub.8 are
independently selected from H, C.sub.1-6alkyl, --C.sub.1-6alkyl-OH
or a bond linking the NHE-binding small molecule to L, provided at
least one is a bond linking the NHE-binding small molecule to L;
R.sub.4 is selected from H, C.sub.1-C.sub.7 alkyl, or a bond
linking the NHE-binding small molecule to L; R.sub.6 is absent or
selected from H and C.sub.1-C.sub.7 alkyl; and Ar1 and Ar2
independently represent an aromatic ring or a heteroaromatic ring;
(b) Core is a Core moiety having the following structure of Formula
(C-I):
##STR00133##
wherein: W is selected from alkylene, polyalkylene glycol,
--C(.dbd.O)--NH-(alkylene)-NH--C(.dbd.O)--,
--C(.dbd.O)--NH-(polyalkylene glycol)-NH--C(.dbd.O)--,
--C(.dbd.O)-(alkylene)-C(.dbd.O)--, --C(.dbd.O)-(polyalkylene
glycol)-C(.dbd.O)-- and cycloalkyl; X is N; Y is C.sub.1-6alkylene;
Z is selected from --NZ.sub.a--C(.dbd.O)--NZ.sub.a--,
--C(.dbd.O)NZ.sub.a--, --NZ.sub.aC(.dbd.O)-- and heteroaryl; each
Z.sub.a is independently selected from hydrogen and C.sub.1-6alkyl;
and (c) L is a bond or linker connecting the Core moiety to the
NHE-binding small molecules, the resulting NHE-binding compound
(i.e., a compound of Formula (II-I)) possessing overall
physicochemical properties that render it substantially impermeable
or substantially systemically non-bioavailable. The Core moiety may
be bound to essentially any position on, or within, the NHE-binding
small molecule moiety, provided that the installation thereof does
not significantly adversely impact activity.
[0307] It is to be noted that, in the structures illustrated
herein, all of the various linkages or bonds will not be shown in
every instance. For example, in one or more of the structures
illustrated above, a bond or connection between the NHE-binding
small molecule moiety and the Core moiety is not always shown.
However, this should not be viewed in a limiting sense. Rather, it
is to be understood that the NHE-binding small molecule moiety is
bound or connected in some way (e.g., by a bond or linker of some
kind) to the Core moiety, such that the resulting NHE-binding
compound is suitable for use (i.e., substantially impermeable or
substantially systemically non-bioavailable in the GI tract).
[0308] The above noted embodiments are further illustrated herein
below. For example, the first representation below of an exemplary
oligomer compound, wherein the various parts of the compound are
identified, is intended to provide a broad context for the
disclosure provided herein. It is to be noted that while each
NHE-binding small molecule moiety in the structure below is the
same, it is within the scope of this disclosure that each is
independently selected and may be the same or different. In the
illustration below, the linker moiety is a polyethylene glycol
(PEG) motif. PEG derivatives are advantageous due in part to their
aqueous solubility, which may help avoid hydrophobic collapse (the
intramolecular interaction of hydrophobic motifs that can occur
when a hydrophobic molecule is exposed to an aqueous environment
(see, e.g., Wiley, R. A.; Rich, D. H. Medical Research Reviews
1993, 13(3), 327-384). The core moiety illustrated below is also
advantageous because it provides some rigidity to the molecule,
allowing an increase in distance between the NHE-binding small
molecule moieties while minimally increasing rotational degrees of
freedom.
##STR00134##
[0309] In designing and making the substantially impermeable or
substantially systemically non-bioavailable NHE-binding compounds
that may be utilized for the treatments detailed in the instant
disclosure, it may in some cases be advantageous to first determine
a likely point of attachment on a NHE-binding small molecule
moiety, where a core or linker might be installed or attached
before making a series of candidate multivalent or polyvalent
compounds. This may be done by one skilled in the art via known
methods by systematically installing functional groups, or
functional groups displaying a fragment of the desired core or
linker, onto various positions of the NHE-binding small molecule
moiety and then testing these adducts to determine whether the
modified compound still retains desired biological properties
(e.g., inhibition of phosphate transport). An understanding of the
SAR of the compound also allows the design of cores and/or linkers
that contribute positively to the activity of the resulting
compounds.
[0310] Another aspect to be considered in the design of cores and
linkers is the limiting or preventing of hydrophobic collapse.
Compounds with extended hydrocarbon functionalities may collapse
upon themselves in an intramolecular fashion, causing an increased
enthalpic barrier for interaction with the desired biological
target. Accordingly, when designing cores and linkers, these are
preferably designed to be resistant to hydrophobic collapse. For
example, conformational constraints such as rigid monocyclic,
bicyclic or polycyclic rings can be installed in a core or linker
to increase the rigidity of the structure. Unsaturated bonds, such
as alkenes and alkynes, may also or alternatively be installed.
Such modifications may ensure the NHE-binding compound is
accessible for productive binding with its target. Furthermore, the
hydrophilicity of the linkers may be improved by adding hydrogen
bond donor or acceptor motifs, or ionic motifs such as amines that
are protonated in the GI, or acids that are deprotonated. Such
modifications will increase the hydrophilicity of the core or
linker and help prevent hydrophobic collapse. Furthermore, such
modifications will also contribute to the impermeability of the
resulting compounds by increasing tPSA.
[0311] It is understood that any embodiment of the compounds of the
present invention, as set forth above, and any specific substituent
set forth herein in such compounds, as set forth above, may be
independently combined with other embodiments and/or substituents
of such compounds to form embodiments of the inventions not
specifically set forth above. In addition, in the event that a list
of substituents is listed for any particular substituent in a
particular embodiment and/or claim, it is understood that each
individual substituent may be deleted from the particular
embodiment and/or claim and that the remaining list of substituents
will be considered to be within the scope of the invention.
Furthermore, it is understood that in the present description,
combinations of substituents and/or variables of the depicted
formulae are permissible only if such contributions result in
stable compounds.
III. Substantially Systemically Bioavailable Compounds
[0312] A. Physical and Performance Properties of Compounds
[0313] Certain of the compounds described herein are designed to be
substantially active in systemic tissues, including the tissues of
the kidney, upon administration via any route including enteral
administration. For enteral administration, including oral
delivery, certain of these compounds are substantially permeable to
the epithelium of the gastrointestinal tract, including the
epithelium of the oral cavity, esophagus, stomach, small intestine,
and/or large intestine. The term "gastrointestinal lumen" is used
interchangeably herein with the term "lumen," to refer to the space
or cavity within a gastrointestinal tract (GI tract, which can also
be referred to as the gut), delimited by the apical membrane of GI
epithelial cells of the subject. In some embodiments, the compounds
are substantially absorbed through the layer of epithelial cells of
the GI tract (also known as the GI epithelium). "Gastrointestinal
mucosa" refers to the layer(s) of cells separating the
gastrointestinal lumen from the rest of the body and includes
gastric and intestinal mucosa, such as the mucosa of the small
intestine. A "gastrointestinal epithelial cell" or a "gut
epithelial cell" as used herein refers to any epithelial cell on
the surface of the gastrointestinal mucosa that faces the lumen of
the gastrointestinal tract, including, for example, an epithelial
cell of the stomach, an intestinal epithelial cell, a colonic
epithelial cell, and the like.
[0314] "Substantially systemically bioavailable" and/or
"substantially permeable" as used herein (as well as variations
thereof) generally include situations in which a statistically
significant amount, and in some embodiments essentially all of the
compound of the present disclosure, enters the bloodstream or
systemic tissues via the gastrointestinal lumen. For example, in
accordance with one or more embodiments of the present disclosure,
preferably at least about 60%, about 70%, about 75%, about 80%,
about 85%, about 90%, about 95%, about 96%, about 97%, about 98%,
about 99%, or even about 99.5%, of the compound enters the
bloodstream or systemic tissues via the gastrointestinal lumen. In
such cases, localization to the bloodstream or systemic tissues
refers to increasing the net movement of a compound across a
gastrointestinal layer of epithelial cells, for example, by way of
both transcellular and paracellular transport, as well as by active
and/or passive transport. The compound in such embodiments
permeates a layer of gastrointestinal epithelial cells in
transcellular transport, for example, through an apical membrane of
an epithelial cell of the small intestine. The compound in these
embodiments may also permeate through the "tight junctions" in
paracellular transport between gastrointestinal epithelial cells
lining the lumen.
[0315] In this regard it is to be further noted, however, that in
alternative embodiments "substantially permeable" or "substantially
systemically bioavailable" provides or allows for some limited
retention in the GI tract to occur (e.g., some detectable amount of
absorption, such as for example less than about 0.1%, 0.5%, 1% or
less than about 30%, 20%, 10%, 5%, etc., the range of retention
being for example between about 1% and 30%, or 5% and 20%,
etc.).
[0316] In this regard it is to be further noted, that in certain
embodiments, due to the substantial permeability and/or substantial
systemic bioavailability of the compounds of the present invention,
no greater than about 50%, 60%, 70%, 80%, 90%, or 95% of a compound
of the invention is recoverable from the feces over, for example, a
24, 36, 48, 60, 72, 84, or 96 hour period following (e.g., enteral)
administration to a subject in need thereof. In some embodiments,
less than about 40%, 30%, 20%, or less than about 10%, or less than
about 5%, of the amount of compound administered is present or
recoverable in the subject's feces. In this respect, it is
understood that a recovered compound can include the sum of the
parent compound and its metabolites derived from the parent
compound, e.g., by means of hydrolysis, conjugation, reduction,
oxidation, N-alkylation, glucuronidation, acetylation, methylation,
sulfation, phosphorylation, or any other modification that adds
atoms to or removes atoms from the parent compound, wherein the
metabolites are generated via the action of any enzyme or exposure
to any physiological environment including, pH, temperature,
pressure, or interactions with foodstuffs as they exist in the
digestive milieu.
[0317] Measurement of fecal recovery of compound and metabolites
can be carried out using standard methodology. For example, a
compound can be administered enterally (e.g., orally) at a suitable
dose (e.g., 10 mg/kg) and feces are then collected at predetermined
times after dosing (e.g., 24 hours, 36 hours, 48 hours, 60 hours,
72 hours, 96 hours). Parent compound and metabolites can be
extracted with organic solvent and analyzed quantitatively using
mass spectrometry. A mass balance analysis of the parent compound
and metabolites (including, parent=M, metabolite 1 [M+16], and
metabolite 2 [M+32]) can be used to determine the percent recovery
in the feces.
[0318] (i) C.sub.max and IC.sub.50
[0319] In some embodiments, the substantially systemically
bioavailable compounds detailed herein, when administered either
alone or in combination with one or more additional
pharmaceutically active compounds or agents to a subject in need
thereof, exhibit a maximum concentration detected in the serum,
defined as C.sub.max, that is about the same as or greater than the
phosphate ion (Pi) transport or uptake inhibitory concentration
IC.sub.50 of the compound. In some embodiments, for instance, the
C.sub.max is about or at least about 5%, 10%, 20%, 30%, 40%, 50%,
60%, 70%, 80%, 90%, 100%, 200%, 300%, 400%, 500% or greater than
the IC.sub.50 for inhibiting Pi transport or uptake. In some
embodiments, the C.sub.max is about 1, 1.5, 2, 2.5, 3, 4, 5, 6, 7,
8, 9, 10, 20, 30, 40, 50, 60, 70, 80, 90, or 100.times. (100 times)
the IC.sub.50 for inhibiting Pi transport or uptake.
[0320] Additionally, or alternatively, it is also to be noted that,
in various embodiments of the present disclosure, one or more of
compounds detailed herein, when administered to a subject in need
thereof, may have a ratio of C.sub.max:IC.sub.50 (for inhibiting Pi
transport or uptake), wherein C.sub.max and IC.sub.50 are expressed
in terms of the same units, of at about or at least about 1, 1.5,
2, 2.5, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50, 60, 70, 80, 90, or
100, or a range in between about 1-100, 1-50, or 1-10.
[0321] Additionally, or alternatively, it is also to be noted that,
in various embodiments of the present disclosure, one or more of
the compounds detailed herein, when administered (e.g., enterally)
either alone or in combination with one or more additional
pharmaceutically active compounds or agents to a subject in need
thereof, may have a C.sub.max of about or greater than about 10
ng/ml, about 12.5 ng/ml, about 15 ng/ml, about 17.5 ng/ml, about 20
ng/ml, about 30 ng/ml, about 40 ng/ml, about 50 ng/ml, about 60
ng/ml, about 70 ng/ml, about 80 ng/ml, about 90 ng/ml, about 100
ng/ml, or about 200 ng/ml, the C.sub.m, being for example within
the range of about 10 ng/ml to about 200 ng/ml, 10 ng/ml to about
100 ng/ml, or about 10 ng/ml to about 50 ng/ml.
[0322] B. Exemplary Substantially Systemically Bioavailable
Compounds
[0323] Generally, the present disclosure encompasses essentially
any small molecule, which may be monovalent or polyvalent, that
binds to, interacts with, and/or modulates NHE3, and has activity
as a phosphate transport inhibitor, including small molecules that
are substantially permeable or substantially systemically
bioavailable upon administration via the gastrointestinal tract or
other route, and including known NHE-binding and NHE-inhibitor
compounds. Certain embodiments thus include compounds that are
generally represented by the "NHE" moiety, as described elsewhere
herein (e.g., supra), wherein NHE is a NHE-binding small
molecule.
[0324] Small molecules suitable for use (i.e., suitable for use as
substantially bioavailable compounds) include those illustrated
below.
[0325] In view of the foregoing, in one particular embodiment, the
following small molecule, disclosed in U.S. Patent Application No.
2005/0054705, the entire content of which (and in particular the
text of pages 1-2 therein) is incorporated herein by reference for
all relevant and consistent purposes, may be suitable for use as a
substantially systemically bioavailable NHE-binding compound.
##STR00135##
[0326] The variables in the structure are defined in the cited
patent application, the details of which are incorporated herein by
reference. In one particularly preferred embodiment, R.sub.6 and
R.sub.7 are a halogen (e.g., Cl), R.sub.5 is lower alkyl (e.g.,
CH.sub.3), and R.sub.1-R.sub.4 are H, the compound having for
example the structure:
##STR00136##
[0327] In yet another particular embodiment, the following small
molecule, disclosed in Canadian Patent Application No. 2,241,531
(or International Patent Publication No. WO 97/24113), the entire
content of which (and in particular pages 1-2 therein) is
incorporated herein for all relevant and consistent purposes, may
be suitable for use as a substantially systemically bioavailable
NHE-binding compound.
##STR00137##
The variables in the structure are defined in the cited patent
application, the details of which are incorporated herein by
reference.
[0328] In yet another particular embodiment, the following small
molecule, disclosed in Canadian Patent Application No. 2,241,531
(or International Patent Publication No. WO 97/24113), the entire
content of which (and in particular page 49 therein) is
incorporated herein for all relevant and consistent purposes, may
be suitable for use as a substantially systemically bioavailable
NHE-binding compound.
##STR00138##
[0329] The variables in the structure are defined in the cited
patent application, the details of which are incorporated herein by
reference.
[0330] In yet another particular embodiment, the following small
molecule, disclosed in Canadian Patent Application No. 2,241,531
(or International Patent Publication No. WO 97/24113), the entire
content of which (and in particular pages 118-120 and 175-177
therein) is incorporated herein for all relevant and consistent
purposes, may be suitable for use as a substantially systemically
bioavailable NHE-binding compound.
##STR00139##
[0331] The variables in the structure are defined in the cited
patent application, the details of which are incorporated herein by
reference.
[0332] In yet another particular embodiment, the following small
molecule, disclosed in Canadian Patent Application No. 2,241,531
(or International Patent Publication No. WO 97/24113), the entire
content of which (and in particular pages 129-131 therein) is
incorporated herein for all relevant and consistent purposes, may
be suitable for use as a substantially systemically bioavailable
NHE-binding compound.
##STR00140##
[0333] The variables in the structure are defined in the cited
patent application, the details of which are incorporated herein by
reference. (In this regard it is to be noted that the substituent Z
within the structure illustrated above is not to be confused with
the moiety Z that, in accordance with the present disclosure, can
be attached to the NHE-binding small molecule in order effective
render the resulting "NHE-Z" molecule substantially
impermeable.).
[0334] In yet another particular embodiment, the following small
molecule, disclosed in Canadian Patent Application No. 2,241,531
(or International Patent Publication No. WO 97/24113), the entire
content of which (and in particular pages 127-129 therein) is
incorporated herein for all relevant and consistent purposes, may
be suitable for use as a substantially systemically bioavailable
NHE-binding compound.
##STR00141##
[0335] The variables in the structure are defined in the cited
patent application, the details of which are incorporated herein by
reference. (In this regard it is to be noted that Z within the ring
of the structure illustrated above is not to be confused with the
moiety Z that, in accordance with the present disclosure, can be
attached to the NHE-binding small molecule in order effective
render the resulting "NHE-Z" molecule substantially
impermeable.)
[0336] In yet another particular embodiment, the following small
molecule, disclosed in Canadian Patent Application No. 2,241,531
(or International Patent Publication No. WO 97/24113), the entire
content of which (and in particular pages 134-137 therein) is
incorporated herein for all relevant and consistent purposes, may
be suitable for use as a substantially systemically bioavailable
NHE-binding compound.
##STR00142##
The variables in the structure are defined in the cited patent
application, the details of which are incorporated herein by
reference.
[0337] In yet another particular embodiment, the following small
molecule, disclosed in Canadian Patent Application No. 2,241,531
(or International Patent Publication No. WO 97/24113), the entire
content of which (and in particular pages 31-32 and 137-139
therein) is incorporated herein for all relevant and consistent
purposes, may be suitable for use as a substantially systemically
bioavailable NHE-binding compound.
##STR00143##
The variables in the structure are defined in the cited patent
application, the details of which are incorporated herein by
reference.
[0338] In yet another particular embodiment, the following small
molecule, disclosed in Canadian Patent Application No. 2,241,531
(or International Patent Publication No. WO 97/24113), the entire
content of which (and in particular pages 37-45 therein) is
incorporated herein for all relevant and consistent purposes, may
be suitable for use as a substantially systemically bioavailable
NHE-binding compound.
##STR00144##
The variables in the structure are defined in the cited patent
application, the details of which are incorporated herein by
reference. (In this regard it is to be noted that Z within the ring
structure illustrated above is not to be confused with the moiety Z
that, in accordance with the present disclosure, can be attached to
the NHE-binding small molecule in order effective render the
resulting "NHE-Z" molecule substantially impermeable.)
[0339] In yet another particular embodiment, the following small
molecule, disclosed in Canadian Patent Application No. 2,241,531
(or International Patent Publication No. WO 97/24113), the entire
content of which (and in particular pages 100-102 therein) is
incorporated herein for all relevant and consistent purposes, may
be suitable for use as a substantially systemically bioavailable
NHE-binding compound.
##STR00145##
The variables in the structure are defined in the cited patent
application, the details of which are incorporated herein by
reference (wherein, in particular, the wavy bonds indicate variable
length, or a variable number of atoms, therein).
[0340] In yet another particular embodiment, the following small
molecule, disclosed in Canadian Patent Application No. 2,241,531
(or International Patent Publication No. WO 97/24113), the entire
content of which (and in particular pages 90-91 therein) is
incorporated herein for all relevant and consistent purposes, may
be suitable for use as a substantially systemically bioavailable
NHE-binding compound.
##STR00146##
The variables in the structure are defined in the cited patent
application, the details of which are incorporated herein by
reference.
[0341] In yet another particular embodiment, the following small
molecule, disclosed in U.S. Pat. No. 5,900,436 (or EP 0822182 B1),
the entire contents of which (and in particular column 1, lines
10-55 therein) are incorporated herein by reference for all
relevant and consistent purposes, may be suitable for use as a
substantially systemically bioavailable NHE-binding compound.
##STR00147##
The variables in the structures are defined in the cited patents,
the details of which are incorporated herein by reference.
[0342] In yet another particular embodiment, the following small
molecule, disclosed in Canadian Patent Application No. 2,241,531
(or International Patent Publication No. WO 97/24113), the entire
content of which (and in particular pages 35-47 therein) is
incorporated herein for all relevant and consistent purposes, may
be suitable for use as a substantially systemically bioavailable
NHE-binding compound.
##STR00148##
The variables in the structure are defined in the cited patent
application, the details of which are incorporated herein by
reference.
[0343] In yet another particular embodiment, the following small
molecule, disclosed in Canadian Patent Application No. 2,241,531
(or International Patent Publication No. WO 97/24113), the entire
content of which (and in particular pages 154-155 therein) is
incorporated herein for all relevant and consistent purposes, may
be suitable for use as a substantially systemically bioavailable
NHE-binding compound.
##STR00149##
The variables in the structure are defined in the cited patent
application, the details of which are incorporated herein by
reference.
[0344] In yet another particular embodiment, the following small
molecule, disclosed in Canadian Patent Application No. 2,241,531
(or International Patent Publication No. WO 97/24113), the entire
content of which (and in particular pages 132-133 therein) is
incorporated herein for all relevant and consistent purposes, may
be suitable for use as a substantially systemically bioavailable
NHE-binding compound.
##STR00150##
The variables in the structure are defined in the cited patent
application, the details of which are incorporated herein by
reference.
[0345] In yet another particular embodiment, the following small
molecule, disclosed in Canadian Patent Application No. 2,241,531
(or International Patent Publication No. WO 97/24113), the entire
content of which (and in particular pages 58-65 AND 141-148
therein) is incorporated herein for all relevant and consistent
purposes, may be suitable for use as a substantially systemically
bioavailable NHE-binding compound.
##STR00151##
The variables in the structure are defined in the cited patent
application, the details of which are incorporated herein by
reference. (In this regard it is to be noted that Z within the ring
structure illustrated above is not to be confused with the moiety Z
that, in accordance with the present disclosure, can be attached to
the NHE-binding small molecule in order effective render the
resulting "NHE-Z" molecule substantially impermeable.)
[0346] In yet another particular embodiment, the following small
molecule, disclosed in U.S. Pat. Nos. 6,911,453 and 6,703,405, the
entire contents of which (and in particular the text of columns 1-7
and 46 of U.S. Pat. No. 6,911,453 and columns 14-15 of U.S. Pat.
No. 6,703,405) are incorporated herein by reference for all
relevant and consistent purposes, may be suitable for use as a
substantially systemically bioavailable NHE-binding compound.
##STR00152##
The variables in the structure are defined in the cited patents,
the details of which are incorporated herein by reference. A
particularly preferred small molecule falling within the
above-noted structure is further illustrated below (see, e.g.,
Example 1 of the U.S. Pat. No. 6,911,453, the entire contents of
which are specifically incorporated herein by reference):
##STR00153##
[0347] In yet another particular embodiment, the following small
molecules, disclosed in U.S. Patent Publication Nos. 2004/0039001,
2004/0224965, 2005/0113396 and 2005/0020612, the entire contents of
which are incorporated herein by reference for all relevant and
consistent purposes, may be suitable for use as a substantially
systemically bioavailable NHE-binding compound).
##STR00154##
The variables in the structures are defined above and/or in one or
more of the cited patent applications, the details of which are
incorporated herein by reference, and/or as illustrated above
(wherein the broken bonds indicate a point of attachment for the Y
moiety to the fused heterocyclic ring). In particular, in various
embodiments the combination of X and Y may be as follows:
##STR00155##
[0348] In a particularly preferred embodiment of the above-noted
structure, the small molecule has the general structure:
##STR00156##
[0349] wherein R.sub.1, R.sub.2 and R.sub.3 may be the same or
different, but are preferably different, and are independently
selected from H, NR'R'' (wherein R' and R'' are independently
selected from H and hydrocarbyl, such as lower alkyl, as defined
elsewhere herein) and the structure:
##STR00157##
[0350] In a more particularly preferred embodiment of the above
structure, a small molecule falling within the above-noted
structure is further illustrated below (see, e.g., compound I1 on
p. 5 of the 2005/0020612 patent application, the entire contents of
which are specifically incorporated herein by reference):
##STR00158##
[0351] In another particularly preferred embodiment, the following
small molecule, disclosed in U.S. Pat. No. 6,399,824, the entire
content of which (and in particular the text of Example 1 therein)
is incorporated herein by reference for all relevant and consistent
purposes, may be suitable for use as a substantially systemically
bioavailable NHE-binding compound.
##STR00159##
[0352] In the structure, R may be preferably selected from H and
(CH.sub.3).sub.2NCH.sub.2CH.sub.2--, with H being particularly
preferred in various embodiments.
[0353] In yet another particular embodiment, the following small
molecule, disclosed in U.S. Pat. No. 6,005,010 (and in particular
columns 1-3 therein), and/or U.S. Pat. No. 6,166,002 (and in
particular columns 1-3 therein), the entire contents of which are
incorporated herein by reference for all relevant and consistent
purposes, may be suitable for use as a substantially systemically
bioavailable NHE-binding compound.
##STR00160##
The variable ("R") in the structure is defined in the cited patent
application, the details of which are incorporated herein by
reference.
[0354] In another embodiment, the NHE-binding small molecules
suitable for use as substantially systemically bioavailable
compounds are disclosed in WO 2010/025856, the entire contents of
which are incorporated herein by reference for all relevant and
consistent purposes, and have the following structure.
##STR00161##
[0355] The variables in the structure are defined in WO
2010/025856, the details of which are incorporated herein by
reference.
[0356] In yet another particularly preferred embodiment, the
following small molecule, disclosed in U.S. Patent Application No.
2008/0194621, the entire content of which (and in particular the
text of Example 1 therein) is incorporated herein by reference for
all relevant and consistent purposes, may be suitable for use as a
substantially systemically bioavailable NHE-binding compound.
TABLE-US-00004 ##STR00162## R.sub.1 R.sub.2 R.sub.3 ##STR00163##
--H --H --NH.sub.2 --H --H --H ##STR00164## --H --H --NH.sub.2 --H
--H --H --NH.sub.2
[0357] The variables ("R.sub.1", "R.sub.2 and "R.sub.3") in the
structure are as defined above, and/or as defined in the cited
patent application, the details of which are incorporated herein by
reference.
[0358] In yet another particularly preferred embodiment, the
following small molecule, disclosed in U.S. Patent Application No.
2007/0225323, the entire content of which (and in particular the
text of Example 36 therein) is incorporated herein by reference for
all relevant and consistent purposes, may be suitable for use as a
substantially systemically bioavailable NHE-binding compound.
##STR00165##
[0359] In yet another particularly preferred embodiment, the
following small molecule, disclosed in U.S. Pat. No. 6,911,453, the
entire content of which (and in particular the text of Example 35
therein) is incorporated herein by reference for all relevant and
consistent purposes, may be suitable for use as a substantially
systemically bioavailable NHE-binding compound.
##STR00166##
[0360] In one particularly preferred embodiment of the present
disclosure, the small molecule may be selected from the group
consisting of:
##STR00167##
[0361] In some embodiments, the substantially systemically
bioavailable NHE-binding and/or modulating compound is selected
from one or more of the following:
##STR00168## ##STR00169##
IV. Pharmaceutical Compositions and Methods of Treatment
[0362] For the purposes of administration, the compounds of the
present invention may be administered to a patient or subject as a
raw chemical or may be formulated as pharmaceutical compositions.
Pharmaceutical compositions of the present invention generally
comprise a compound of the invention and a pharmaceutically
acceptable carrier, diluent, or excipient. The compound is present
in the composition in an amount which is effective to treat a
particular disease or condition of interest, as described herein,
and preferably with acceptable toxicity to the subject. The
activity of compound(s) can be determined by one skilled in the
art, for example, as described in the Examples below. Appropriate
concentrations and dosages can be readily determined by one skilled
in the art.
[0363] A compound or composition of the invention may be used in a
method for treating essentially any disease or other condition in a
subject which would benefit from phosphate uptake inhibition in the
gastrointestinal tract and/or kidneys.
[0364] For example, by way of explanation, but not limitation,
kidney damage reduces the production and activity of renal 1-alpha
hydroxylase, leading to lower 1,25-dihydroxy vitamin D. Decreased
vitamin D levels limit gastrointestinal calcium absorption, leading
to a decline in serum calcium levels. The combination of lower
1,25-dihydroxy vitamin D and lower serum calcium levels
synergistically stimulate parathyroid tissue to produce and secrete
PTH. A loss of nephrons also impairs Pi excretion, but serum P
levels are actively defended by the actions of PTH and FGF-23, and
by higher serum P levels, which considerably enhance urinary
PO.sub.4 excretion. However, tubular actions of PTH and FGF-23
cannot maintain serum P levels in the face of continual nephron
loss. Once renal insufficiency progresses to the loss of about
40-50% of renal function, the decrease in the amount of functioning
renal tissue does not allow excretion of the full amount of
ingested phosphate required to maintain homeostasis. As a result,
hyperphosphatemia develops. In addition, a rise in serum P levels
impedes renal 1-alpha hydroxylase activity, further suppressing
activated vitamin D levels, and further stimulating PTH, leading to
secondary hyperparathyroidism (sHPTH).
[0365] Phosphorus imbalance, however, does not necessarily equate
with hyperphosphatemia. Rather, the vast majority of CKD patients
not yet on dialysis are normophosphatemic but their phosphorus
balance is positive with the excess phosphorus being disposed in
the vasculature in the form of ectopic calcification, e.g.
intima-localized vascular calcification. Clinically, patients with
CKD have elevated levels of FGF-23 that are significantly
associated with deteriorating renal function and with decreased
calcitriol levels, and it has been hypothesized that the synthesis
of FGF-23 is induced by the presence of excess P in the body
consecutive to renal failure.
[0366] Furthermore, an unrecognized effect on cardiovascular
disease is post-prandial phosphatemia, i.e. serum P excursion
secondary to meal intake. Further still, studies have investigated
the acute effect of phosphorus loading on endothelial function in
vitro and in vivo. Exposing bovine aortic endothelial cells to a
phosphorus load increased production of reactive oxygen species and
decreased nitric oxide, a known vasodilator agent. In the acute P
loading study in healthy volunteers described above, it was found
that the flow mediated dilation correlated inversely with
postprandial serum P (Shuto et al., 2009b, J. Am. Soc. Nephrol., v.
20, no. 7, p. 1504-1512).
[0367] Accordingly, in certain embodiments, a compound or
composition of the invention can be used in a method selected from
one or more of the following: a method for treating
hyperphosphatemia, optionally postprandial hyperphosphatemia; a
method for treating a renal disease (e.g., chronic kidney disease
(CKD), end stage renal disease (ESRD)); a method for reducing serum
creatinine levels; a method for treating proteinuria; a method for
delaying time to renal replacement therapy (RRT) such as dialysis;
a method for reducing FGF23 levels; a method for reducing the
hyperphosphatemic effect of active vitamin D; a method for
attenuating hyperparathyroidism such as secondary
hyperparathyroidism; a method for reducing serum parathyroid
hormone (PTH or iPTH); a method for reducing inderdialytic weight
gain (IDWG); a method for improving endothelial dysfunction
optionally induced by postprandial serum phosphate; a method for
reducing vascular calcification or attenuating intima-localized
vascular calcification; a method for reducing urinary phosphorus
(e.g., enterally administering a GI-acting, substantially
systemically non-bioavailable compound); a method for increasing
urinary phosphorus (e.g., administering a substantially
systemically bioavailable compound, administering a substantially
systemically non-bioavailable compound via a route other than
enteral administration); a method for normalizing serum phosphorus
levels; a method for reducing phosphate burden in an elderly
patient; a method for decreasing dietary phosphate uptake; a method
for reducing postprandial calcium absorption; a method for reducing
renal hypertrophy; a method for reducing heart hypertrophy; and a
method for treating obstructive sleep apnea.
[0368] In some embodiments, the invention provides the use of a
compound or composition for treating hyperphosphatemia, optionally
postprandial hyperphosphatemia; treating a renal disease (e.g.,
chronic kidney disease (CKD), end stage renal disease (ESRD));
reducing serum creatinine levels; treating proteinuria; delaying
time to renal replacement therapy (RRT) such as dialysis; reducing
FGF23 levels; for reducing the hyperphosphatemic effect of active
vitamin D; attenuating hyperparathyroidism such as secondary
hyperparathyroidism; reducing serum parathyroid hormone (PTH or
iPTH); reducing inderdialytic weight gain (IDWG); improving
endothelial dysfunction optionally induced by postprandial serum
phosphate; reducing vascular calcification or attenuating
intima-localized vascular calcification; reducing urinary
phosphorus (e.g., enterally administering a GI-acting,
substantially systemically non-bioavailable compound); increasing
urinary phosphorus (e.g., administering a substantially
systemically bioavailable compound, administering a substantially
systemically non-bioavailable compound via a route other than
enteral administration); normalizing serum phosphorus levels;
reducing phosphate burden in an elderly patient; decreasing dietary
phosphate uptake; reducing postprandial calcium absorption;
reducing renal hypertrophy; reducing heart hypertrophy; and
treating obstructive sleep apnea.
[0369] In some embodiments, the invention provides the use of a
compound or composition in the manufacture of a medicament for:
treating hyperphosphatemia, optionally postprandial
hyperphosphatemia; treating a renal disease (e.g., chronic kidney
disease (CKD), end stage renal disease (ESRD)); reducing serum
creatinine levels; treating proteinuria; delaying time to renal
replacement therapy (RRT) such as dialysis; reducing FGF23 levels;
for reducing the hyperphosphatemic effect of active vitamin D;
attenuating hyperparathyroidism such as secondary
hyperparathyroidism; reducing serum parathyroid hormone (PTH or
iPTH); reducing inderdialytic weight gain (IDWG); improving
endothelial dysfunction optionally induced by postprandial serum
phosphate; reducing vascular calcification or attenuating
intima-localized vascular calcification; reducing urinary
phosphorus (e.g., enterally administering a GI-acting,
substantially systemically non-bioavailable compound); increasing
urinary phosphorus (e.g., administering a substantially
systemically bioavailable compound, administering a substantially
systemically non-bioavailable compound via a route other than
enteral administration); normalizing serum phosphorus levels;
reducing phosphate burden in an elderly patient; decreasing dietary
phosphate uptake; reducing postprandial calcium absorption;
reducing renal hypertrophy; reducing heart hypertrophy; and
treating obstructive sleep apnea.
[0370] In some embodiments, the invention provides a pharmaceutical
composition comprising a compound or composition for: treating
hyperphosphatemia, optionally postprandial hyperphosphatemia;
treating a renal disease (e.g., chronic kidney disease (CKD), end
stage renal disease (ESRD)); reducing serum creatinine levels;
treating proteinuria; delaying time to renal replacement therapy
(RRT) such as dialysis; reducing FGF23 levels; for reducing the
hyperphosphatemic effect of active vitamin D; attenuating
hyperparathyroidism such as secondary hyperparathyroidism; reducing
serum parathyroid hormone (PTH or iPTH); reducing inderdialytic
weight gain (IDWG); improving endothelial dysfunction optionally
induced by postprandial serum phosphate; reducing vascular
calcification or attenuating intima-localized vascular
calcification; reducing urinary phosphorus (e.g., enterally
administering a GI-acting, substantially systemically
non-bioavailable compound); increasing urinary phosphorus (e.g.,
administering a substantially systemically bioavailable compound,
administering a substantially systemically non-bioavailable
compound via a route other than enteral administration);
normalizing serum phosphorus levels; reducing phosphate burden in
an elderly patient; decreasing dietary phosphate uptake; reducing
postprandial calcium absorption; reducing renal hypertrophy;
reducing heart hypertrophy; and treating obstructive sleep
apnea.
[0371] Hyperphosphatemia refers to a condition in which there is an
elevated level of phosphate in the blood. Average serum phosphorus
mass in a human adult typically range from about 2.5-4.5 mg/dL
(about 0.81-1.45 mmol/L). Levels are often about 50% higher in
infants and about 30% higher in children because of growth hormone
effects. Hence, certain methods include treating an adult human
patient having hyperphosphatemia, where the patient has serum
phosphorus mass of about or at least about 4.5, 4.6, 4.7, 4.8, 4.9,
5.0, 5.1, 5.2, 5.3, 5.4, or 5.5 mg/dL. In some aspects, the
treatment reduces serum phosphate concentrations or levels in a
hyperphosphatemic subject to about 150%, 145%, 140%, 135%, 130%,
125%, 120%, 115%, 110%, 105%, or 100% (normalized) of the normal
serum phosphate levels (e.g., 2.5-4.5 mg/dL or 0.81-1.45 mmol/L for
an adult). In some aspects, the treatment regimen results in and/or
includes monitoring phosphate levels so that they remain within the
range of about 2.5-4.5 mg/dL (about 0.81-1.45 mmol/L). Also
included are methods of treating a child or adolescent human
patient, where the patient has serum phosphorus mass of about or at
least about 6.0, 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8, 6.9, 7.0,
7.1, 7.2, 7.3, 7.4, 7.5, 7.6, 7.7, 7.8, 7.9, or 8.0 mg/dL. As noted
herein, in these and related embodiments, administration of a
compound or composition described herein may reduce serum
phosphorus mass in the subject by about or at least about 5%, 10%,
20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%, 200% or more.
[0372] Certain embodiments relate to methods of treating chronic
kidney disease (CKD), a condition characterized by the progressive
loss of renal function. Common causes of CKD include diabetes
mellitus, hypertension, and glomerulonephritis. Hence, certain
methods include treating a subject with CKD, where the subject
optionally also has one or more of the foregoing conditions.
[0373] In some aspects, a subject is classified as having CKD if
they have a glomerular filtration rate (GFR) of less than 60
mL/min/1.73 m.sup.2 for about 3 months, whether or not they also
present with kidney damage. Certain methods thus include treating a
subject with a GFR (e.g., an initial GFR, prior to treatment) of
about or less than about 60, 55, 50, 45, 40, 30, 35, 20, 25, 20,
15, or 10 mL/min/1.73 m.sup.2 or so. In certain embodiments,
administration of a compound or composition described herein may
result in an increase in GFR of about or at least about 5%, 10%,
20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%, 200% or more.
[0374] CKD is most often characterized according to the stage of
disease: Stage 1, Stage 2, Stage, 3, Stage 4, and Stage 5. Stage 1
CKD includes subjects with kidney damage and a normal or relatively
high GFR of about or greater than about 90 mL/min/1.73 m.sup.2.
Stage 2 CKD includes subjects with kidney damage and a GFR of about
60-89 mL/min/1.73 m.sup.2. Stage 3 CKD includes subjects with
kidney damage and a GFR of about 30-59 mL/min/1.73 m.sup.2. Stage 4
CKD includes subjects with kidney damage and a GFR of about 15-29
mL/min/1.73 m.sup.2. Stage 5 CKD includes subjects with established
kidney failure and a GFR of less than about 15 mL/min/1.73 m.sup.2.
Stage 5 CKD is also referred to as end-stage renal disease (ESRD).
Accordingly, in certain methods, a subject has Stage 1, 2, 3, 4, or
5, CKD and one or more of its associated clinical characteristics
(e.g., defined GFR, kidney damage). In some embodiments, the
subject has ESRD and any one or more of its associated clinical
characteristics, as described herein and known in the art.
[0375] CKD can be characterized according to the affected parts of
the kidney. For instance, in certain aspects, CKD includes
vascular-associated CKD, including large vessel disease such as
bilateral renal artery stenosis, and small vessel disease such as
ischemic nephropathy, hemolytic-uremic syndrome and vasculitis. In
certain aspects, CKD includes glomerular-associated CKD, including
primary glomerular disease such as focal segmental
glomerulosclerosis and IgA nephritis, and secondary Glomerular
diseases such as diabetic nephropathy and lupus nephritis. Also
included is tubulointerstitial-associated CKD, including polycystic
kidney disease, drug and toxin-induced chronic tubulointerstitial
nephritis, and reflux nephropathy. Certain subjects being treated
for CKD may thus have one or more foregoing CKD-associated
characteristics.
[0376] Certain aspects relate to methods of treating a subject with
kidney damage or one or more symptoms/clinical signs of kidney
damage. Examples of kidney damage (e.g., CKD-associated kidney
damage) and its related symptoms include pathological abnormalities
and markers of damage, including abnormalities identified in blood
testing (e.g., high blood or serum levels of creatinine, creatinine
clearance), urine testing (e.g., proteinuria), and/or imaging
studies.
[0377] Creatinine is a break-down product of creatine phosphate in
muscle, and provides an easily-measured and useful indicator of
renal health. Normal human reference ranges for blood or serum
creatinine range from about 0.5 to 1.0 mg/dL (about 45-90
.mu.mol/l) for women and about 0.7 to 1.2 mg/dL (about 60-110
mol/L) for men. Hence, certain subjects for treatment according to
the methods described herein (e.g., initially, prior to treatment)
may have blood or serum creatine levels that are about or greater
than about 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0
mg/dL. In these and related embodiments, administration of a
compound or composition described herein may reduce overall blood
or serum creatinine levels in a subject by about or at least about
5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%, or 200% or
more.
[0378] Creatinine clearance rate (C.sub.Cr or CrCl) refers to the
volume of blood plasma that is cleared of creatinine per unit time;
it is measured by comparing the levels of creatinine in blood
relative to urine over a period of time (e.g., 24 hours). Creatine
clearance is often measured as milliliters/minute (ml/min) or as a
function of body mass (ml/min/kg). Depending on the test performed,
normal values range from about 97-137 ml/min for males and about
88-128 ml/min for females. Reduced creatinine clearance provides a
useful sign of kidney damage. Hence, certain male subjects for
treatment according to the methods described herein (e.g.,
initially, prior to treatment) may have a C.sub.Cr of about or less
than about 97, 96, 95, 94, 93, 92, 91, 90, 89, 88, 87, 86, 85, 84,
83, 82, 81, 80, 79, 78, 77, 76, 75, 74, 73, 72, 71, 70, 69, 68, 67,
66, 65, 64, 63, 62, 61, 60, 59, 58, 57, 56, 55, 54, 53, 52, 51, 50
or less. Certain female subjects for treatment according to the
methods described herein (e.g., initially, prior to treatment) may
have a C.sub.Cr of about or less than about 88, 87, 86, 85, 84, 83,
82, 81, 80, 79, 78, 77, 76, 75, 74, 73, 72, 71, 70, 69, 68, 67, 66,
65, 64, 63, 62, 61, 60, 59, 58, 57, 56, 55, 54, 53, 52, 51, 50, 49,
47, 46, 45, 44, 43, 42, 41, 40 or less. In some embodiments,
administration of a compound or composition described herein may
maintain or increase the C.sub.Cr in a subject by about or at least
about 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%, or
200% or more.
[0379] Proteinuria refers to a condition of excess protein in the
urine. It is associated with variety of disease conditions
including kidney damage. Proteinuria is often characterized as a
urine protein/creatinine ratio of greater than about 45 mg/mmol, or
in specific tests an albumin/creatine ratio of greater than about
30 mg/mmol. Certain subjects for treatment according to the methods
provided herein (e.g., prior to treatment) have proteinuria, alone
or in combination with CKD or other kidney damage, including
subjects with a urine protein/creatinine ratio of about or greater
than about 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105,
110, 115, or 120 mg/mmol and/or a urine albumin/creatinine ratio of
about or greater than about 30, 35, 40, 50, 55, 60, 65, 70, 75, 80,
85, 90, 95, 100, 105, 110, 115, or 120 mg/mmol. In these and
related embodiments, administration of a compound or composition
described herein may treat proteinuria, for instance, by reducing
the urine protein/creatinine ratio and/or the urine
albumin/creatinine ratio by about or at least about 5%, 10%, 20%,
30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%, or 200% or more.
[0380] CKD is associated with a variety of clinical symptoms.
Examples include high blood pressure (hypertension), urea
accumulation, hyperkalemia, anemia, hyperphosphatemia,
hypocalcemia, metabolic acidosis, and atherosclerosis. Thus, in
certain methods, a subject with CKD may also have or be at risk for
having one or more of the foregoing clinical symptoms. In specific
aspects, the subject with CKD has or is at risk for having
hyperphosphatemia, as described herein.
[0381] Renal replacement therapy (RRT) relates to the various
life-supporting treatments for renal failure, including those
initiated in the later stages of CKD and ESRD. Examples of RRT
include dialysis, hemodialysis, hemofiltration, and renal
transplantation. In certain embodiments, a subject for treatment
according to the methods provided herein is about to undergo, is
undergoing, or has undergone one or more types of RRT. In some
embodiments, the subject is not yet undergoing RRT, and
administration of a compound described herein delays the time to
initiating RRT (e.g., relative to an untreated state) by about or
at least about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 weeks, or by
about or at least about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12
months, or by about or at least about 1, 2, 3, 4, 5, 6, 7, 8, 9,
10, 11, 12 years or more.
[0382] Fibroblast growth factor 23 (FGF23) regulates phosphorus and
vitamin D metabolism. It also promotes phosphaturia and decreases
production of calcitriol. Increased FGF23 levels associate with
mortality, left ventricular hypertrophy (or left ventricular mass
index), myocardial performance, endothelial dysfunction, and
progression of CKD. Indeed, FGF23 levels increase progressively in
early CKD, presumably as a physiological adaptation to maintain
normal serum phosphate levels or normal phosphorus balance. FGF23
levels might also contribute directly to tissue injury in the
heart, vessels, and kidneys. Certain embodiments thus relate to the
treatment of subjects having increased FGF23 levels in blood or
serum (see, e.g., Kirkpantur et al., Nephrol Dial Transplant.
26:1346-54, 2011), including subjects with CKD and subjects
undergoing dialysis/hemodialysis. In some aspects, administration
of a compound or composition described herein reduces the logarithm
of FGF23 levels in blood or serum by about or at least about 5%,
10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%, or 200% or
more.
[0383] Vitamin D stimulates, inter alia, the absorption of
phosphate ions in the small intestine. Hence, excess levels or
activity of Vitamin D can lead to increased phosphate levels and
hyperphosphatemia. Certain embodiments thus relate to methods for
reducing the hyperphosphatemic effect of active vitamin D, for
instance, in a subject having elevated levels or activity of
Vitamin D. In some aspects, the subject has Vitamin D toxicity due
to over-ingestion of Vitamin D.
[0384] Hyperparathyroidism is a disorder in which the parathyroid
glands produce too much parathyroid hormone (PTH). Secondary
hyperparathyroidism is characterized by the excessive secretion of
PTH in response to hypocalcemia and associated hypertrophy of the
parathyroid glands. CKD is the most common cause of secondary
hyperparathyroidism, generally because the kidneys fail to convert
sufficient vitamin D into its active form and to excrete sufficient
phosphate. Insoluble calcium phosphate forms in the body and thus
removes calcium from the circulation, leading to hypocalcemia. The
parathyroid glands then further increase the secretion of PTH in an
attempt to increase serum calcium levels. Certain subjects for
treatment according to the methods provided herein may thus present
(e.g., initially, prior to treatment) with hyperparathyroidism
and/or increased PTH levels, optionally in combination with CKD,
hyperphosphatemia, hypocalcemia, or other condition or symptom
described herein. In some aspects, administration of a compound or
composition described herein may reduce hyperparathyroidism
including secondary hyperparathyroidism in a subject in need
thereof. In some aspects, administration of a compound or
composition described herein may reduce PTH levels by about or at
least about 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%,
or 200% or more, for instance, by reducing serum phosphate levels
and the associated formation of insoluble calcium phosphate,
increasing available calcium, and thereby reducing the
hypocalcemia-induced production of PTH.
[0385] In certain embodiments, the administration of a compound
described herein, for instance, a dual-active compound that
inhibits both transport of Pi and NHE3-mediated antiport of sodium
and hydrogen ions, can provide multiple therapeutic effects to a
subject with CKD. In some instances, the administration of a
dual-active compound reduces the logarithm of FGF23 levels and
serum parathyroid hormone (PTH) levels by about or at least about
5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%, or 200% or
more relative to an untreated state, reduces blood pressure, and
reduces proteinuria by at least about 5%, 10%, 20%, 30%, 40%, 50%,
60%, 70%, 80%, 90%, 100%, or 200% or more relative to an untreated
state.
[0386] In particular embodiments, the administration of a compound
described herein, for instance, a dual-active compound that
inhibits both transport of Pi and NHE3-mediated antiport of sodium
and hydrogen ions, can provide multiple therapeutic effects to a
subject with ESRD (or Stage 5 CKD). In specific instances, the
administration of a dual-active compound reduces serum phosphate
concentrations or levels by about or at least about 5%, 10%, 20%,
30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%, or 200% or more relative
to an untreated state, and reduces inderdialytic weight gain (IDWG)
by about or at least about 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%,
80%, 90%, 100%, or 200% or more relative to an untreated state.
IDWG is an easily measurable parameter that is routinely assessed
before, during, or after dialysis (see Sarkar et al., Semin Dial.
19:429-33, 2006).
[0387] Hyperphosphatemia can lead to endothelial dysfunction in
both healthy subjects and those with kidney disease, independently
of vascular calcification (see, e.g., Di Marco et al., Kidney
International. 83:213-222, 2013). Management of serum phosphate
level by dietary phosphate restriction or phosphate binders can
prevent such subjects from developing cardiovascular disease.
Studies have also shown that dietary phosphate restriction can
improve aortic endothelial dysfunction (e.g., in CKD with
hyperphosphatemia) by increasing the activatory phosphorylation of
endothelial nitric oxide synthase and Akt (see, e.g., Van et al., J
Clin Biochem Nutr. 51:27-32, 2012). Certain subjects for treatment
according to the methods provided herein may have or be at risk for
having endothelial dysfunction, optionally combined with
hyperphosphatemia, kidney disease, or any other condition described
herein. By reducing postprandial or dietary phosphate uptake, alone
or in combination with dietary phosphate restriction,
administration of a compound or composition described herein may
reduce the risk of developing endothelial dysfunction, or may
improve already-existing endothelial dysfunction, including
endothelial dysfunction induced by postprandial serum
phosphate.
[0388] Hyperphosphatemia is a primary inducer of vascular
calcification (see Giachelli, Kidney Int. 75:890-897, 2009).
Calcium phosphate deposition, mostly in the form of apatite, is the
hallmark of vascular calcification and can occur in the blood
vessels, myocardium, and cardiac valves. Together with passive
deposition of calcium-phosphate in extra-skeletal tissues,
inorganic phosphate can also induce arterial calcification directly
through "ossification" of the tunica media in the vasculature.
Moreover, vascular smooth muscle cells respond to elevated
phosphate levels by undergoing an osteochondrogenic phenotype
change and mineralizing their extracellular matrix through a
mechanism requiring sodium-dependent phosphate cotransporters.
[0389] Intimal calcification is usually found in atherosclerotic
lesions. Medial calcification is commonly observed in
age-associated arteriosclerosis and diabetes, and is the major form
of calcification observed in ESRD. Indeed, extensive calcification
of the arterial wall and soft tissues is a frequent feature of
patients with CKD, including those with ESRD. In valves,
calcification is a defining feature of aortic valve stenosis, and
occurs in both the leaflets and ring, predominantly at sites of
inflammation and mechanical stress. These mechanical changes are
associated with increased arterial pulse wave velocity and pulse
pressure, and lead to impaired arterial distensibility, increased
afterload favoring left ventricular hypertrophy, and compromised
coronary perfusion (see Guerin et al., Circulation. 103:987-992,
2001). Both intimal and medial calcifications may thus contribute
to the morbidity and mortality associated with cardiovascular
disease, and are likely to be major contributors to the significant
increase in cardiovascular mortality risk observed in CKD and ESRD
patients. Control of serum phosphate may thus reduce the formation
of calcium/phosphate products and thereby reduce vascular
calcification. Accordingly, certain of the subjects for treatment
according to the methods provided herein may have or be at risk for
developing vascular calcification, including intimal and/or medial
calcification, optionally combined with any of hyperphosphatemia,
CKD, and ESRD. In some embodiments, administration of a compound or
composition described herein reduces the risk of developing or
reduces the formation or levels of vascular calcification in a
subject in need thereof. In particular embodiments, administration
of a compound or composition described herein may reduce vascular
calcification by about or at least about 5%, 10%, 20%, 30%, 40%,
50%, 60%, 70%, 80%, 90%, 100%, or 200% or more, for example,
relative to an untreated state.
[0390] Elderly patients can be especially susceptible to increased
phosphate. For instance, dietary and genetic manipulation studies
provide in vivo evidence that phosphate toxicity accelerates the
aging process and suggest a novel role for phosphate in mammalian
aging (see, e.g., Ohnishi and Razzaque, FASEB J. 24:3562-71, 2010).
These studies show that excess phosphate associates with many signs
of premature aging, including kyphosis, uncoordinated movement,
hypogonadism, infertility, skeletal muscle wasting, emphysema, and
osteopenia, as well as generalized atrophy of the skin, intestine,
thymus, and spleen. Certain embodiments thus relate to reducing
phosphate burden in an elderly patient, for instance, to reduce any
one or more signs of premature aging, comprising administering to
the elderly patient a compound described herein. In some instances,
an elderly patient is about or at least about 60, 61, 62, 63, 64,
65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81,
82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98,
99, 100 or more years of age.
[0391] Hypertrophy refers to the increase in the volume of an organ
or tissue due to the enlargement of its component cells.
Hyperphosphatemia associates with myocardial hypertrophy including
left ventricular hypertrophy (see Neves et al., Kidney Int.
66:2237-44, 2004; and Achinger and Ayus, Am Soc Nephrol. 17(12
Suppl 3):S255-61, 2006) and compensatory renal hypertrophy
including glomerular hypertrophy, the latter being often-observed
in CKD. Certain subjects for treatment according to the methods
provided herein may have (e.g., initially, prior to treatment)
myocardial hypertrophy, renal hypertrophy, or both, alone or in
combination with CKD or kidney damage. In some embodiments,
administration of a compound described herein may reduce myocardial
hypertrophy and/or renal hypertrophy by about or at least about 5%,
10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%, 200% or more
relative to an untreated state.
[0392] Sleep apnea is a sleep disorder characterized by abnormal
pauses in breathing or abnormally low breathing during sleep.
Pauses in breathing are referred to as apneas, and low-breathing
events are referred to as hypopneas. These events can last from
seconds to minutes, and may occur numerous times in an hour (e.g.,
>30 times an hour). The apnea-hypoapnea index (AHI) is
calculated as the total number of apneas or hypoapneas divided by
the hours of sleep. Mild, moderate, and severe sleep apnea are
defined respectively as AHI 5-14, 15-29 and .gtoreq.30 events/hour.
Obstructive sleep apnea (OSA) is the most common type of sleep
apnea. In OSA, breathing is obstructed upon collapse of the walls
of soft tissue in the airway, which occurs as the muscle tone of
the body ordinarily relaxes during sleep. Chronic severe OSA can
lead to hypoxemia (low blood oxygen), sleep deprivation, and other
complications, including cardiovascular complications. Moreover, a
high prevalence of CKD is present in severe OSA patients, including
those without hypertension or diabetes. Significantly positive
correlations are also found between severity of OSA and renal
function impairment (see Chou et al., Nephrol. Dial. Transplant.
0:1-6, 2011). Moreover, acute hypoxia is associated with
proteinuria, a sign of kidney damage or dysfunction (see Luks et
al., J Am Soc Nephrol. 19:2262-2271, 2008). OSA and hypoxia thus
associate with kidney dysfunction and OSA is considered a
stand-alone risk factor for CKD (Chou et al., supra). Accordingly,
certain subjects for treatment according to the methods provided
herein may have OSA, alone or in combination with CKD or other
symptoms of kidney damage. Administration of a compound or
composition described herein to a subject with OSA may reduce the
AHI by about or at least about 5%, 10%, 20%, 30%, 40%, 50%, 60%,
70%, 80% or more.
[0393] Administration of the compounds of the invention, or their
pharmaceutically acceptable salts, in pure form or in an
appropriate pharmaceutical composition, can be carried out via any
of the accepted modes of administration of agents for serving
similar utilities. The pharmaceutical compositions of the invention
can be prepared by combining a compound of the invention with an
appropriate pharmaceutically acceptable carrier, diluent or
excipient, and may be formulated into preparations in solid,
semi-solid, liquid or gaseous forms, such as tablets, capsules,
powders, granules, ointments, solutions, suppositories, injections,
inhalants, gels, microspheres, and aerosols. Typical routes of
administering such pharmaceutical compositions include, without
limitation, oral, topical, transdermal, inhalation, parenteral,
sublingual, buccal, rectal, vaginal, and intranasal. The term
parenteral as used herein includes subcutaneous injections,
intravenous, intramuscular, intrasternal injection or infusion
techniques. Pharmaceutical compositions of the invention are
formulated so as to allow the active ingredients contained therein
to be bioavailable upon administration of the composition to a
patient. Compositions that will be administered to a subject or
patient take the form of one or more dosage units, where for
example, a tablet may be a single dosage unit, and a container of a
compound of the invention in aerosol form may hold a plurality of
dosage units. Actual methods of preparing such dosage forms are
known, or will be apparent, to those skilled in this art; for
example, see Remington: The Science and Practice of Pharmacy, 20th
Edition (Philadelphia College of Pharmacy and Science, 2000). The
composition to be administered will, in any event, contain a
therapeutically effective amount of a compound of the invention, or
a pharmaceutically acceptable salt thereof, for treatment of a
disease or condition of interest in accordance with the teachings
of this invention.
[0394] A pharmaceutical composition of the invention may be in the
form of a solid or liquid. In one aspect, the carrier(s) are
particulate, so that the compositions are, for example, in tablet
or powder form. The carrier(s) may be liquid, with the compositions
being, for example, an oral syrup, injectable liquid or an aerosol,
which is useful in, for example, inhalatory administration.
[0395] When intended for oral administration, the pharmaceutical
composition is preferably in either solid or liquid form, where
semi-solid, semi-liquid, suspension and gel forms are included
within the forms considered herein as either solid or liquid.
[0396] As a solid composition for oral administration, the
pharmaceutical composition may be formulated into a powder,
granule, compressed tablet, pill, capsule, chewing gum, wafer or
the like form. Such a solid composition will typically contain one
or more inert diluents or edible carriers. In addition, one or more
of the following may be present: binders such as
carboxymethylcellulose, ethyl cellulose, microcrystalline
cellulose, gum tragacanth or gelatin; excipients such as starch,
lactose or dextrins, disintegrating agents such as alginic acid,
sodium alginate, Primogel, corn starch and the like; lubricants
such as magnesium stearate or Sterotex; glidants such as colloidal
silicon dioxide; sweetening agents such as sucrose or saccharin; a
flavoring agent such as peppermint, methyl salicylate or orange
flavoring; and a coloring agent.
[0397] When the pharmaceutical composition is in the form of a
capsule, for example, a gelatin capsule, it may contain, in
addition to materials of the above type, a liquid carrier such as
polyethylene glycol or oil.
[0398] The pharmaceutical composition may be in the form of a
liquid, for example, an elixir, syrup, solution, emulsion or
suspension. The liquid may be for oral administration or for
delivery by injection, as two examples. When intended for oral
administration, preferred composition contain, in addition to the
present compounds, one or more of a sweetening agent,
preservatives, dye/colorant and flavor enhancer. In a composition
intended to be administered by injection, one or more of a
surfactant, preservative, wetting agent, dispersing agent,
suspending agent, buffer, stabilizer and isotonic agent may be
included.
[0399] The liquid pharmaceutical compositions of the invention,
whether they be solutions, suspensions or other like form, may
include one or more of the following adjuvants: sterile diluents
such as water for injection, saline solution, preferably
physiological saline, Ringer's solution, isotonic sodium chloride,
fixed oils such as synthetic mono or diglycerides which may serve
as the solvent or suspending medium, polyethylene glycols,
glycerin, propylene glycol or other solvents; antibacterial agents
such as benzyl alcohol or methyl paraben; antioxidants such as
ascorbic acid or sodium bisulfite; chelating agents such as
ethylenediaminetetraacetic acid; buffers such as acetates, citrates
or phosphates and agents for the adjustment of tonicity such as
sodium chloride or dextrose. The parenteral preparation can be
enclosed in ampoules, disposable syringes or multiple dose vials
made of glass or plastic. Physiological saline is a preferred
adjuvant. An injectable pharmaceutical composition is preferably
sterile.
[0400] A liquid pharmaceutical composition of the invention
intended for either parenteral or oral administration should
contain an amount of a compound of the invention such that a
suitable dosage will be obtained.
[0401] The pharmaceutical composition of the invention may be
intended for topical administration, in which case the carrier may
suitably comprise a solution, emulsion, ointment or gel base. The
base, for example, may comprise one or more of the following:
petrolatum, lanolin, polyethylene glycols, bee wax, mineral oil,
diluents such as water and alcohol, and emulsifiers and
stabilizers. Thickening agents may be present in a pharmaceutical
composition for topical administration. If intended for transdermal
administration, the composition may include a transdermal patch or
iontophoresis device.
[0402] The pharmaceutical composition of the invention may be
intended for rectal administration, in the form, for example, of a
suppository, which will melt in the rectum and release the drug.
The composition for rectal administration may contain an oleaginous
base as a suitable nonirritating excipient. Such bases include,
without limitation, lanolin, cocoa butter and polyethylene
glycol.
[0403] The pharmaceutical composition of the invention may include
various materials, which modify the physical form of a solid or
liquid dosage unit. For example, the composition may include
materials that form a coating shell around the active ingredients.
The materials that form the coating shell are typically inert, and
may be selected from, for example, sugar, shellac, and other
enteric coating agents. Alternatively, the active ingredients may
be encased in a gelatin capsule.
[0404] The pharmaceutical composition of the invention in solid or
liquid form may include an agent that binds to the compound of the
invention and thereby assists in the delivery of the compound.
Suitable agents that may act in this capacity include a monoclonal
or polyclonal antibody, a protein or a liposome.
[0405] The pharmaceutical composition of the invention may consist
of dosage units that can be administered as an aerosol. The term
aerosol is used to denote a variety of systems ranging from those
of colloidal nature to systems consisting of pressurized packages.
Delivery may be by a liquefied or compressed gas or by a suitable
pump system that dispenses the active ingredients. Aerosols of
compounds of the invention may be delivered in single phase,
bi-phasic, or tri-phasic systems in order to deliver the active
ingredient(s). Delivery of the aerosol includes the necessary
container, activators, valves, subcontainers, and the like, which
together may form a kit. One skilled in the art, without undue
experimentation may determine preferred aerosols.
[0406] The pharmaceutical compositions of the invention may be
prepared by methodology well known in the pharmaceutical art. For
example, a pharmaceutical composition intended to be administered
by injection can be prepared by combining a compound of the
invention with sterile, distilled water so as to form a solution. A
surfactant may be added to facilitate the formation of a
homogeneous solution or suspension. Surfactants are compounds that
non-covalently interact with the compound of the invention so as to
facilitate dissolution or homogeneous suspension of the compound in
the aqueous delivery system.
[0407] The compounds of the invention, or their pharmaceutically
acceptable salts, are administered in a therapeutically effective
amount, which will vary depending upon a variety of factors
including the activity of the specific compound employed; the
metabolic stability and length of action of the compound; the age,
body weight, general health, sex, and diet of the patient; the mode
and time of administration; the rate of excretion; the drug
combination; the severity of the particular disorder or condition;
and the subject undergoing therapy.
[0408] In certain embodiments, a typical dosage of the
substantially impermeable or substantially systemically
non-bioavailable, compound may be between about 0.2 mg per day and
about 2 g per day, or between about 1 mg and about 1 g per day, or
between about 5 mg and about 500 mg, or between about 10 mg and
about 250 mg per day, which is administered to a subject in need of
treatment.
[0409] The frequency of administration of the compounds and
compositions described herein may vary from once-a-day (QD) to
twice-a-day (BID) or thrice-a-day (TID), etc., the precise
frequency of administration varying with, for example, the
patient's condition, the dosage, etc.
[0410] Compounds of the invention, or pharmaceutically acceptable
derivatives thereof, may also be administered simultaneously with,
prior to, or after administration of one or more other therapeutic
or biologically active agents, dietary supplements, or any
combination thereof. Such combination therapy includes
administration of a single pharmaceutical dosage formulation which
contains a compound of the invention and one or more additional
active agents, as well as administration of the compound of the
invention and each active agent in its own separate pharmaceutical
dosage formulation. For example, a compound of the invention and
the other active agent can be administered to the patient together
in a single oral dosage composition such as a tablet or capsule, or
each agent administered in separate oral dosage formulations. Where
separate dosage formulations are used, the compounds of the
invention and one or more additional active agents can be
administered at essentially the same time, i.e., concurrently, or
at separately staggered times, i.e., sequentially; combination
therapy is understood to include all these regimens.
[0411] For example, in certain embodiments, the additional
biologically active agent included in a pharmaceutical composition
(or method) of the invention is selected, for example, from vitamin
D.sub.2 (ergocalciferol), vitamin D.sub.3 (cholecalciferol), active
vitamin D (calcitriol) and active vitamin D analogs (e.g.
doxercalciferol, paricalcitol).
[0412] In other specific embodiments, the additional biologically
active agent included in a pharmaceutical composition (or method)
of the invention is a phosphate binder, such as sevelamer (e.g.,
Renvela.RTM. (sevelamer carbonate), Renagel.RTM. (sevelamer
hydrochloride)), lanthanum carbonate (e.g., Fosrenol.RTM.), calcium
carbonate (e.g., Calcichew.RTM., Titralac.RTM.), calcium acetate
(e.g. PhosLo.RTM., Phosex.RTM.), calcium acetate/magnesium
carbonate (e.g., Renepho.RTM., OsvaRen.RTM.), MCI-196, ferric
citrate (e.g., Zerenex.TM.), magnesium iron hydroxycarbonate (e.g.,
Fermagate.TM.), aluminum hydroxide (e.g., Alucaps.RTM.,
Basaljel.RTM.), APS1585, SBR-759, PA-21, and the like.
[0413] In some aspects, the compounds may act synergistically with
phosphate binders by providing a higher efficacy than the sum of
the efficacy of the transport inhibitor and that of a phosphate
binder administered alone. Without wishing to be bound by theory,
it is believed that the synergy results from the distinct
mechanisms of action of a phosphate transport inhibitor and a
phosphate binder. More specifically, a phosphate transport
inhibitor blocks the epithelial inward transport of phosphate ions
whereas phosphate binders sequester free phosphate ions in the
lumen of the intestine.
[0414] The efficacy of a phosphate binder, as measured by its in
vivo binding capacity (mole of phosphate ions bound per gram of
binder) is essentially dictated by: i) the density of binding sites
(i.e., amine groups in Renvela.RTM. (sevelamer), a polymeric amine
material; or multivalent cations such calcium or lanthanum in
PhosLo.RTM. (Calcium acetate) or Fosrenol (lanthanum carbonate));
and ii) the affinity of said binding sites for phosphate ions.
Notably only a fraction of the binding sites are available for
phosphate binding in vivo as other anions, such as bile acids and
fatty acids, compete for the binding sites and therefore lower
efficacy. Bound phosphate ions are in equilibrium with free
phosphate in the intestinal lumen and are themselves subject to
intense pumping from phosphate transport proteins lining up the
epithelia. Experiments have shown that the efficacy of phosphate
intestinal uptake is remarkably high, exceeding 95% of the
phosphate presented to the epithelia. It is believed that the
active transport of phosphate contributes to lower the luminal free
phosphate concentration and therefore to drive the binding
equilibrium of a phosphate binder to lower binding capacity. It is
also believed that by reducing the phosphate intestinal transport
using a phosphate transport inhibitor, one restores a higher in
vivo binding capacity of phosphate sequestering agents. The
synergistic effect is thought to be even more pronounced when the
contribution of active phosphate transport is increased as a result
of, e.g. vitamin D treatment, an agent promoting NaPi2b
expression.
[0415] In some embodiments, the additional biologically active
agent is an inhibitor of the intestinal sodium-dependent phosphate
transporter (NaPi2b inhibitor). Examples of NaPi2b inhibitors can
be found, for instance, in International Application Nos.
PCT/US2011/043267; PCT/US2011/043261; PCT/US2011/043232;
PCT/US2011/043266; and PCT/US2011/043263; and U.S. Pat. No.
8,134,015, each of which is incorporated by reference in its
entirety.
[0416] In certain embodiments, the additionally biologically active
agent is niacin or nicotinamide.
[0417] It is understood that in the present description,
combinations of substituents and/or variables of the depicted
formulae are permissible only if such contributions result in
stable or reasonably stable compounds.
[0418] It will also be appreciated by those skilled in the art that
in the process described herein the functional groups of
intermediate compounds may need to be protected by suitable
protecting groups. Such functional groups include hydroxy, amino,
mercapto, and carboxylic acid. Suitable protecting groups for
hydroxy include trialkylsilyl or diarylalkylsilyl (for example,
t-butyldimethylsilyl, t-butyldiphenylsilyl or trimethylsilyl),
tetrahydropyranyl, benzyl, and the like. Suitable protecting groups
for amino, amidino and guanidino include t-butoxycarbonyl,
benzyloxycarbonyl, and the like. Suitable protecting groups for
mercapto include --C(O)--R'' (where R'' is alkyl, aryl or
arylalkyl), p-methoxybenzyl, trityl and the like. Suitable
protecting groups for carboxylic acid include alkyl, aryl or
arylalkyl esters. Protecting groups may be added or removed in
accordance with standard techniques, which are known to one skilled
in the art and as described herein. The use of protecting groups is
described in detail in Green, T. W. and P. G. M. Wutz, Protective
Groups in Organic Synthesis (1999), 3rd Ed., Wiley. As one of skill
in the art would appreciate, the protecting group may also be a
polymer resin such as a Wang resin, Rink resin or a
2-chlorotrityl-chloride resin.
[0419] It will also be appreciated by those skilled in the art,
although such protected derivatives of compounds of this invention
may not possess pharmacological activity as such, they may be
administered to a mammal and thereafter metabolized in the body to
form compounds of the invention which are pharmacologically active.
Such derivatives may therefore be described as "prodrugs". All
prodrugs of compounds of this invention are included within the
scope of the invention.
[0420] Furthermore, all compounds of the invention which exist in
free base or acid form can be converted to their pharmaceutically
acceptable salts by treatment with the appropriate inorganic or
organic base or acid by methods known to one skilled in the art.
Salts of the compounds of the invention can be converted to their
free base or acid form by standard techniques.
Definitions and Terminology
[0421] "Amino" refers to the --NH.sub.2 radical.
[0422] "Aminocarbonyl" refers to the --C(.dbd.O)NH.sub.2
radical.
[0423] "Carboxy" refers to the --CO.sub.2H radical. "Carboxylate"
refers to a salt or ester thereof.
[0424] "Cyano" refers to the --CN radical.
[0425] "Hydroxy" or "hydroxyl" refers to the --OH radical.
[0426] "Imino" refers to the =NH radical.
[0427] "Nitro" refers to the --NO.sub.2 radical.
[0428] "Oxo" or "carbonyl" refers to the =O radical.
[0429] "Thioxo" refers to the =S radical.
[0430] "Guanidinyl" (or "guanidine") refers to the
--NHC(.dbd.NH)NH.sub.2 radical.
[0431] "Amidinyl" (or "amidine") refers to the --C(.dbd.NH)NH.sub.2
radical.
[0432] "Phosphate" refers to the --OP(.dbd.O)(OH).sub.2
radical.
[0433] "Phosphonate" refers to the --P(.dbd.O)(OH).sub.2
radical.
[0434] "Phosphinate" refers to the --PH(.dbd.O)OH radical, wherein
each R.sup.a is independently an alkyl group as defined herein.
[0435] "Sulfate" refers to the --OS(.dbd.O).sub.2OH radical.
[0436] "Sulfonate" or "hydroxysulfonyl" refers to the
--S(.dbd.O).sub.2OH radical.
[0437] "Sulfinate" refers to the --S(.dbd.O)OH radical.
[0438] "Sulfonyl" refers to a moiety comprising a --SO.sub.2--
group. For example, "alkysulfonyl" or
[0439] "alkylsulfone" refers to the --SO.sub.2--R.sup.a group,
wherein R.sup.a is an alkyl group as defined herein.
[0440] "Alkyl" refers to a straight or branched hydrocarbon chain
radical consisting solely of carbon and hydrogen atoms, which is
saturated or unsaturated (i.e., contains one or more double and/or
triple bonds), having from one to twelve carbon atoms (C.sub.1-12
alkyl), preferably one to eight carbon atoms (C.sub.1-C.sub.8
alkyl) or one to six carbon atoms (C.sub.1-C.sub.6 alkyl), and
which is attached to the rest of the molecule by a single bond,
e.g., methyl, ethyl, n-propyl, 1-methylethyl (iso-propyl), n-butyl,
n-pentyl, 1,1-dimethylethyl (t-butyl), 3-methylhexyl,
2-methylhexyl, ethenyl, prop-i-enyl, but-i-enyl, pent-i-enyl,
penta-1,4-dienyl, ethynyl, propynyl, butynyl, pentynyl, hexynyl,
and the like. Unless stated otherwise specifically in the
specification, an alkyl group may be optionally substituted.
[0441] "Alkylene" or "alkylene chain" refers to a straight or
branched divalent hydrocarbon chain linking the rest of the
molecule to a radical group, consisting solely of carbon and
hydrogen, which is saturated or unsaturated (i.e., contains one or
more double and/or triple bonds), and having from one to twelve
carbon atoms, e.g., methylene, ethylene, propylene, n-butylene,
ethenylene, propenylene, n-butenylene, propynylene, n-butynylene,
and the like. The alkylene chain is attached to the rest of the
molecule through a single or double bond and to the radical group
through a single or double bond. The points of attachment of the
alkylene chain to the rest of the molecule and to the radical group
can be through one carbon or any two carbons within the chain.
Unless stated otherwise specifically in the specification, an
alkylene chain may be optionally substituted.
[0442] "Alkoxy" refers to a radical of the formula --OR.sub.a where
R.sub.a is an alkyl radical as defined above containing one to
twelve carbon atoms. Unless stated otherwise specifically in the
specification, an alkoxy group may be optionally substituted.
[0443] "Alkylamino" refers to a radical of the formula --NHR.sub.a
or --NR.sub.aR.sub.a where each R.sub.a is, independently, an alkyl
radical as defined above containing one to twelve carbon atoms.
Unless stated otherwise specifically in the specification, an
alkylamino group may be optionally substituted.
[0444] "Thioalkyl" refers to a radical of the formula --SR.sub.a
where R.sub.a is an alkyl radical as defined above containing one
to twelve carbon atoms. Unless stated otherwise specifically in the
specification, a thioalkyl group may be optionally substituted.
[0445] "Aryl" refers to a hydrocarbon ring system radical
comprising hydrogen, 6 to 18 carbon atoms and at least one aromatic
ring. For purposes of this invention, the aryl radical may be a
monocyclic, bicyclic, tricyclic or tetracyclic ring system, which
may include fused or bridged ring systems. Aryl radicals include,
but are not limited to, aryl radicals derived from aceanthrylene,
acenaphthylene, acephenanthrylene, anthracene, azulene, benzene,
chrysene, fluoranthene, fluorene, as-indacene, s-indacene, indane,
indene, naphthalene, phenalene, phenanthrene, pleiadene, pyrene,
and triphenylene. Unless stated otherwise specifically in the
specification, the term "aryl" or the prefix "ar-" (such as in
"aralkyl") is meant to include aryl radicals that are optionally
substituted.
[0446] "Aralkyl" refers to a radical of the formula
--R.sub.b--R.sub.c where R.sub.b is an alkylene chain as defined
above and R.sub.c is one or more aryl radicals as defined above,
for example, benzyl, diphenylmethyl and the like. Unless stated
otherwise specifically in the specification, an aralkyl group may
be optionally substituted.
[0447] "Cycloalkyl" or "carbocyclic ring" refers to a stable
non-aromatic monocyclic or polycyclic hydrocarbon radical
consisting solely of carbon and hydrogen atoms, which may include
fused or bridged ring systems, having from three to fifteen carbon
atoms, preferably having from three to ten carbon atoms, and which
is saturated or unsaturated and attached to the rest of the
molecule by a single bond. Monocyclic radicals include, for
example, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl,
cycloheptyl, and cyclooctyl. Polycyclic radicals include, for
example, adamantyl, norbornyl, decalinyl,
7,7-dimethyl-bicyclo[2.2.1]heptanyl, and the like. Unless otherwise
stated specifically in the specification, a cycloalkyl group may be
optionally substituted.
[0448] "Cycloalkylalkyl" refers to a radical of the formula
--R.sub.bR.sub.d where R.sub.d is an alkylene chain as defined
above and R.sub.g is a cycloalkyl radical as defined above. Unless
stated otherwise specifically in the specification, a
cycloalkylalkyl group may be optionally substituted.
[0449] "Fused" refers to any ring structure described herein which
is fused to an existing ring structure in the compounds of the
invention. When the fused ring is a heterocyclyl ring or a
heteroaryl ring, any carbon atom on the existing ring structure
which becomes part of the fused heterocyclyl ring or the fused
heteroaryl ring may be replaced with a nitrogen atom.
[0450] "Halo" or "halogen" refers to bromo, chloro, fluoro or
iodo.
[0451] "Haloalkyl" refers to an alkyl radical, as defined above,
that is substituted by one or more halo radicals, as defined above,
e.g., trifluoromethyl, difluoromethyl, trichloromethyl,
2,2,2-trifluoroethyl, 1,2-difluoroethyl, 3-bromo-2-fluoropropyl,
1,2-dibromoethyl, and the like. Unless stated otherwise
specifically in the specification, a haloalkyl group may be
optionally substituted.
[0452] "Heterocyclyl" or "heterocyclic ring" refers to a stable 3-
to 18-membered non-aromatic ring radical which consists of two to
twelve carbon atoms and from one to six heteroatoms selected from
the group consisting of nitrogen, oxygen and sulfur. Unless stated
otherwise specifically in the specification, the heterocyclyl
radical may be a monocyclic, bicyclic, tricyclic or tetracyclic
ring system, which may include fused or bridged ring systems; and
the nitrogen, carbon or sulfur atoms in the heterocyclyl radical
may be optionally oxidized; the nitrogen atom may be optionally
quaternized; and the heterocyclyl radical may be partially or fully
saturated. Examples of such heterocyclyl radicals include, but are
not limited to, dioxolanyl, thienyl[1,3]dithianyl,
decahydroisoquinolyl, imidazolinyl, imidazolidinyl,
isothiazolidinyl, isoxazolidinyl, morpholinyl, octahydroindolyl,
octahydroisoindolyl, 2-oxopiperazinyl, 2-oxopiperidinyl,
2-oxopyrrolidinyl, oxazolidinyl, piperidinyl, piperazinyl,
4-piperidonyl, pyrrolidinyl, pyrazolidinyl, quinuclidinyl,
thiazolidinyl, tetrahydrofuryl, trithianyl, tetrahydropyranyl,
thiomorpholinyl, thiamorpholinyl, 1-oxo-thiomorpholinyl, and
1,1-dioxo-thiomorpholinyl. Unless stated otherwise specifically in
the specification, Unless stated otherwise specifically in the
specification, a heterocyclyl group may be optionally
substituted.
[0453] "N-heterocyclyl" refers to a heterocyclyl radical as defined
above containing at least one nitrogen and where the point of
attachment of the heterocyclyl radical to the rest of the molecule
is through a nitrogen atom in the heterocyclyl radical. Unless
stated otherwise specifically in the specification, a
N-heterocyclyl group may be optionally substituted.
[0454] "Heterocyclylalkyl" refers to a radical of the formula
--R.sub.bR.sub.c where R.sub.b is an alkylene chain as defined
above and Re is a heterocyclyl radical as defined above, and if the
heterocyclyl is a nitrogen-containing heterocyclyl, the
heterocyclyl may be attached to the alkyl radical at the nitrogen
atom. Unless stated otherwise specifically in the specification, a
heterocyclylalkyl group may be optionally substituted.
[0455] "Heteroaryl" refers to a 5- to 14-membered ring system
radical comprising hydrogen atoms, one to thirteen carbon atoms,
one to six heteroatoms selected from the group consisting of
nitrogen, oxygen and sulfur, and at least one aromatic ring. For
purposes of this invention, the heteroaryl radical may be a
monocyclic, bicyclic, tricyclic or tetracyclic ring system, which
may include fused or bridged ring systems; and the nitrogen, carbon
or sulfur atoms in the heteroaryl radical may be optionally
oxidized; the nitrogen atom may be optionally quaternized. Examples
include, but are not limited to, azepinyl, acridinyl,
benzimidazolyl, benzothiazolyl, benzindolyl, benzodioxolyl,
benzofuranyl, benzooxazolyl, benzothiazolyl, benzothiadiazolyl,
benzo[b][1,4]dioxepinyl, 1,4-benzodioxanyl, benzonaphthofuranyl,
benzoxazolyl, benzodioxolyl, benzodioxinyl, benzopyranyl,
benzopyranonyl, benzofuranyl, benzofuranonyl, benzothienyl
(benzothiophenyl), benzotriazolyl,
benzo[4,6]imidazo[1,2-a]pyridinyl, carbazolyl, cinnolinyl,
dibenzofuranyl, dibenzothiophenyl, furanyl, furanonyl,
isothiazolyl, imidazolyl, indazolyl, indolyl, indazolyl,
isoindolyl, indolinyl, isoindolinyl, isoquinolyl, indolizinyl,
isoxazolyl, naphthyridinyl, oxadiazolyl, 2-oxoazepinyl, oxazolyl,
oxiranyl, 1-oxidopyridinyl, 1-oxidopyrimidinyl, 1-oxidopyrazinyl,
1-oxidopyridazinyl, 1-phenyl-1H-pyrrolyl, phenazinyl,
phenothiazinyl, phenoxazinyl, phthalazinyl, pteridinyl, purinyl,
pyrrolyl, pyrazolyl, pyridinyl, pyrazinyl, pyrimidinyl,
pyridazinyl, quinazolinyl, quinoxalinyl, quinolinyl, quinuclidinyl,
isoquinolinyl, tetrahydroquinolinyl, thiazolyl, thiadiazolyl,
triazolyl, tetrazolyl, triazinyl, and thiophenyl (i.e., thienyl).
Unless stated otherwise specifically in the specification, a
heteroaryl group may be optionally substituted.
[0456] "N-heteroaryl" refers to a heteroaryl radical as defined
above containing at least one nitrogen and where the point of
attachment of the heteroaryl radical to the rest of the molecule is
through a nitrogen atom in the heteroaryl radical. Unless stated
otherwise specifically in the specification, an N-heteroaryl group
may be optionally substituted.
[0457] "Heteroarylalkyl" refers to a radical of the formula
--R.sub.bR.sub.f where R.sub.b is an alkylene chain as defined
above and R.sub.f is a heteroaryl radical as defined above. Unless
stated otherwise specifically in the specification, a
heteroarylalkyl group may be optionally substituted.
[0458] The term "substituted" used herein means any of the above
groups (i.e., alkyl, alkylene, alkoxy, alkylamino, thioalkyl, aryl,
aralkyl, cycloalkyl, cycloalkylalkyl, haloalkyl, heterocyclyl,
N-heterocyclyl, heterocyclylalkyl, heteroaryl, N-heteroaryl and/or
heteroarylalkyl) wherein at least one hydrogen atom is replaced by
a bond to a non-hydrogen atoms such as, but not limited to: a
halogen atom such as F, Cl, Br, and I; an oxygen atom in groups
such as hydroxyl groups, carboxyl groups, phosphate groups, sulfate
groups, alkoxy groups, and ester groups; a sulfur atom in groups
such as thiol groups, thioalkyl groups, sulfinate groups, sulfone
groups, sulfonyl groups, and sulfoxide groups; a phosphorus atom in
groups such as phosphinate groups and phosphonate groups; a
nitrogen atom in groups such as guanidine groups, amines, amides,
alkylamines, dialkylamines, arylamines, alkylarylamines,
diarylamines, N-oxides, imides, and enamines; a silicon atom in
groups such as trialkylsilyl groups, dialkylarylsilyl groups,
alkyldiarylsilyl groups, and triarylsilyl groups; and other
heteroatoms in various other groups. "Substituted" also means any
of the above groups in which one or more hydrogen atoms are
replaced by a higher-order bond (e.g., a double- or triple-bond) to
a heteroatom such as oxygen in oxo, carbonyl, carboxyl, and ester
groups; and nitrogen in groups such as imines, oximes, hydrazones,
and nitriles. For example, "substituted" includes any of the above
groups in which one or more hydrogen atoms are replaced with
--NR.sub.gR.sub.h, --NR.sub.gC(.dbd.O)R.sub.h,
--NR.sub.gC(.dbd.O)NR.sub.gR.sub.h, --NR.sub.gC(.dbd.O)OR.sub.h,
--NR.sub.gSO.sub.2R.sub.h, --OC(.dbd.O)NR.sub.gR.sub.h, --OR.sub.g,
--SR.sub.g, --SOR.sub.g, --SO.sub.2R.sub.g, --OSO.sub.2R.sub.g,
--SO.sub.2OR.sub.g, =NSO.sub.2R.sub.g, and
--SO.sub.2NR.sub.gR.sub.h. "Substituted" also means any of the
above groups in which one or more hydrogen atoms are replaced with
--C(.dbd.O)R.sub.g, --C(.dbd.O)OR.sub.g,
--C(.dbd.O)NR.sub.gR.sub.h, --CH.sub.2SO.sub.2R.sub.g,
--CH.sub.2SO.sub.2NR.sub.gR.sub.h,
--(CH.sub.2CH.sub.2O).sub.1-10R.sub.g,
--(CH.sub.2CH.sub.2O).sub.2-10R.sub.g,
--(OCH.sub.2CH.sub.2).sub.1-10R.sub.g and
--(OCH.sub.2CH.sub.2).sub.2-10R.sub.g. In the foregoing, R.sub.g
and R.sub.h are the same or different and independently hydrogen,
alkyl, alkoxy, alkylamino, thioalkyl, aryl, aralkyl, cycloalkyl,
cycloalkylalkyl, haloalkyl, heterocyclyl, N-heterocyclyl,
heterocyclylalkyl, heteroaryl, N-heteroaryl and/or heteroarylalkyl.
"Substituted" further means any of the above groups in which one or
more hydrogen atoms are replaced by a bond to an amino, cyano,
hydroxyl, imino, nitro, oxo, thioxo, halo, alkyl, alkoxy,
alkylamino, thioalkyl, aryl, aralkyl, cycloalkyl, cycloalkylalkyl,
haloalkyl, heterocyclyl, N-heterocyclyl, heterocyclylalkyl,
heteroaryl, N-heteroaryl and/or heteroarylalkyl group. The above
non-hydrogen groups are generally referred to herein as
"substituents" or "non-hydrogen substituents". In addition, each of
the foregoing substituents may also be optionally substituted with
one or more of the above substituents.
[0459] The articles "a" and "an" are used herein to refer to one or
to more than one (i.e., to at least one) of the grammatical object
of the article. By way of example, "an element" means one element
or more than one element.
[0460] By "about" is meant a quantity, level, value, number,
frequency, percentage, dimension, size, amount, weight or length
that varies by as much as 30, 25, 20, 15, 10, 9, 8, 7, 6, 5, 4, 3,
2 or 1% to a reference quantity, level, value, number, frequency,
percentage, dimension, size, amount, weight, length, or other unit
described herein.
[0461] The term "activate" refers to the application of physical,
chemical, or biochemical conditions, substances or processes that a
receptor (e.g., pore receptor) to structurally change in a way that
allows passage of ions, molecules, or other substances.
[0462] The term "active state" refers to the state or condition of
a receptor in its non-resting condition.
[0463] "Efflux" refers to the movement or flux of ions, molecules,
or other substances from an intracellular space to an extracellular
space.
[0464] "Enteral" or "enteric" administration refers to
administration via the gastrointestinal tract, including oral,
sublingual, sublabial, buccal, and rectal administration, and
including administration via a gastric or duodenal feeding
tube.
[0465] The term "inactive state" refers to the state of a receptor
in its original endogenous state, that is, its resting state.
[0466] The term "modulating" includes "increasing" or "enhancing,"
as well as "decreasing" or "reducing," typically in a statistically
significant or a physiologically significant amount as compared to
a control. An "increased" or "enhanced" amount is typically a
"statistically significant" amount, and may include an increase
that is about 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0,
2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.2, 3.4, 3.6,
3.8, 4.0, 4.2, 4.3, 4.4, 4.6, 4.8, 5, 6, 7, 8, 9, 10, 15, 20, 30,
40, 50 or more times (e.g., 100, 200, 500, 1000 times) (including
all integers and decimal points and ranges in between and above 1,
e.g., 5.5, 5.6, 5.7, 5.8, etc.) the amount produced by a control
(e.g., the absence or lesser amount of a compound, a different
compound or treatment), or the amount of an earlier time-point
(e.g., prior to treatment with a compound). A "decreased" or
"reduced" amount is typically a "statistically significant" amount,
and may include a 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%,
12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 25%, 30%, 35%, 40%,
45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or 100%
decrease (including all integers and decimal points and ranges in
between) in the amount or activity produced by a control (e.g., the
absence or lesser amount of a compound, a different compound or
treatment), or the amount of an earlier time-point (e.g., prior to
treatment with a compound).
[0467] "Prodrug" is meant to indicate a compound that may be
converted under physiological conditions or by solvolysis to a
biologically active compound of the invention. Thus, the term
"prodrug" refers to a metabolic precursor of a compound of the
invention that is pharmaceutically acceptable. A prodrug may be
inactive when administered to a subject in need thereof, but is
converted in vivo to an active compound of the invention. Prodrugs
are typically rapidly transformed in vivo to yield the parent
compound of the invention, for example, by hydrolysis in blood. The
prodrug compound often offers advantages of solubility, tissue
compatibility or delayed release in a mammalian organism (see,
Bundgard, H., Design of Prodrugs (1985), pp. 7-9, 21-24 (Elsevier,
Amsterdam)). A discussion of prodrugs is provided in Higuchi, T.,
et al., A.C.S. Symposium Series, Vol. 14, and in Bioreversible
Carriers in Drug Design, Ed. Edward B. Roche, American
Pharmaceutical Association and Pergamon Press, 1987.
[0468] The term "prodrug" is also meant to include any covalently
bonded carriers, which release the active compound of the invention
in vivo when such prodrug is administered to a mammalian subject.
Prodrugs of a compound of the invention may be prepared by
modifying functional groups present in the compound of the
invention in such a way that the modifications are cleaved, either
in routine manipulation or in vivo, to the parent compound of the
invention. Prodrugs include compounds of the invention wherein a
hydroxy, amino or mercapto group is bonded to any group that, when
the prodrug of the compound of the invention is administered to a
mammalian subject, cleaves to form a free hydroxy, free amino or
free mercapto group, respectively. Examples of prodrugs include,
but are not limited to, acetate, formate and benzoate derivatives
of alcohol or amide derivatives of amine functional groups in the
compounds of the invention and the like.
[0469] The invention disclosed herein is also meant to encompass
the in vivo metabolic products of the disclosed compounds. Such
products may result from, for example, the oxidation, reduction,
hydrolysis, amidation, esterification, and the like of the
administered compound, primarily due to enzymatic processes.
Accordingly, the invention includes compounds produced by a process
comprising administering a compound of this invention to a mammal
for a period of time sufficient to yield a metabolic product
thereof. Such products are typically identified by administering a
radiolabelled compound of the invention in a detectable dose to an
animal, such as rat, mouse, guinea pig, monkey, or to human,
allowing sufficient time for metabolism to occur, and isolating its
conversion products from the urine, blood or other biological
samples.
[0470] "Mammal" includes humans and both domestic animals such as
laboratory animals and household pets (e.g., cats, dogs, swine,
cattle, sheep, goats, horses, rabbits), and non-domestic animals
such as wildlife and the like.
[0471] "Optional" or "optionally" means that the subsequently
described event or circumstances may or may not occur, and that the
description includes instances where said event or circumstance
occurs and instances in which it does not. For example, "optionally
substituted aryl" means that the aryl radical may or may not be
substituted and that the description includes both substituted aryl
radicals and aryl radicals having no substitution.
[0472] "Pharmaceutically acceptable carrier, diluent or excipient"
includes without limitation any adjuvant, carrier, excipient,
glidant, sweetening agent, diluent, preservative, dye/colorant,
flavor enhancer, surfactant, wetting agent, dispersing agent,
suspending agent, stabilizer, isotonic agent, solvent, or
emulsifier which has been approved by the United States Food and
Drug Administration as being acceptable for use in humans or
domestic animals.
[0473] "Pharmaceutically acceptable salt" includes both acid and
base addition salts.
[0474] "Pharmaceutically acceptable acid addition salt" refers to
those salts which retain the biological effectiveness and
properties of the free bases, which are not biologically or
otherwise undesirable, and which are formed with inorganic acids
such as, but are not limited to, hydrochloric acid, hydrobromic
acid, sulfuric acid, nitric acid, phosphoric acid and the like, and
organic acids such as, but not limited to, acetic acid,
2,2-dichloroacetic acid, adipic acid, alginic acid, ascorbic acid,
aspartic acid, benzenesulfonic acid, benzoic acid,
4-acetamidobenzoic acid, camphoric acid, camphor-10-sulfonic acid,
capric acid, caproic acid, caprylic acid, carbonic acid, cinnamic
acid, citric acid, cyclamic acid, dodecylsulfuric acid,
ethane-1,2-disulfonic acid, ethanesulfonic acid,
2-hydroxyethanesulfonic acid, formic acid, fumaric acid, galactaric
acid, gentisic acid, glucoheptonic acid, gluconic acid, glucuronic
acid, glutamic acid, glutaric acid, 2-oxo-glutaric acid,
glycerophosphoric acid, glycolic acid, hippuric acid, isobutyric
acid, lactic acid, lactobionic acid, lauric acid, maleic acid,
malic acid, malonic acid, mandelic acid, methanesulfonic acid,
mucic acid, naphthalene-1,5-disulfonic acid, naphthalene-2-sulfonic
acid, 1-hydroxy-2-naphthoic acid, nicotinic acid, oleic acid,
orotic acid, oxalic acid, palmitic acid, pamoic acid, propionic
acid, pyroglutamic acid, pyruvic acid, salicylic acid,
4-aminosalicylic acid, sebacic acid, stearic acid, succinic acid,
tartaric acid, thiocyanic acid, p-toluenesulfonic acid,
trifluoroacetic acid, undecylenic acid, and the like.
[0475] "Pharmaceutically acceptable base addition salt" refers to
those salts which retain the biological effectiveness and
properties of the free acids, which are not biologically or
otherwise undesirable. These salts are prepared from addition of an
inorganic base or an organic base to the free acid. Salts derived
from inorganic bases include, but are not limited to, the sodium,
potassium, lithium, ammonium, calcium, magnesium, iron, zinc,
copper, manganese, aluminum salts and the like. Preferred inorganic
salts are the ammonium, sodium, potassium, calcium, and magnesium
salts. Salts derived from organic bases include, but are not
limited to, salts of primary, secondary, and tertiary amines,
substituted amines including naturally occurring substituted
amines, cyclic amines and basic ion exchange resins, such as
ammonia, isopropylamine, trimethylamine, diethylamine,
triethylamine, tripropylamine, diethanolamine, ethanolamine,
deanol, 2-dimethylaminoethanol, 2-diethylaminoethanol,
dicyclohexylamine, lysine, arginine, histidine, caffeine, procaine,
hydrabamine, choline, betaine, benethamine, benzathine,
ethylenediamine, glucosamine, methylglucamine, theobromine,
triethanolamine, tromethamine, purines, piperazine, piperidine,
N-ethylpiperidine, polyamine resins and the like. Particularly
preferred organic bases are isopropylamine, diethylamine,
ethanolamine, trimethylamine, dicyclohexylamine, choline and
caffeine.
[0476] Often crystallizations produce a solvate of the compound of
the invention. As used herein, the term "solvate" refers to an
aggregate that comprises one or more molecules of a compound of the
invention with one or more molecules of solvent. The solvent may be
water, in which case the solvate may be a hydrate. Alternatively,
the solvent may be an organic solvent. Thus, the compounds of the
present invention may exist as a hydrate, including a monohydrate,
dihydrate, hemihydrate, sesquihydrate, trihydrate, tetrahydrate and
the like, as well as the corresponding solvated forms. The compound
of the invention may be true solvates, while in other cases, the
compound of the invention may merely retain adventitious water or
be a mixture of water plus some adventitious solvent.
[0477] A "pharmaceutical composition" refers to a formulation of a
compound of the invention and a medium generally accepted in the
art for the delivery of the biologically active compound to
mammals, e.g., humans. Such a medium includes all pharmaceutically
acceptable carriers, diluents or excipients therefor.
[0478] The compounds of the invention, or their pharmaceutically
acceptable salts may contain one or more asymmetric centers and may
thus give rise to enantiomers, diastereomers, and other
stereoisomeric forms that may be defined, in terms of absolute
stereochemistry, as (R)- or (S)- or, as (D)- or (L)- for amino
acids. The present invention is meant to include all such possible
isomers, as well as their racemic and optically pure forms.
Optically active (+) and (-), (R)- and (S)-, or (D)- and
(L)-isomers may be prepared using chiral synthons or chiral
reagents, or resolved using conventional techniques, for example,
chromatography and fractional crystallization. Conventional
techniques for the preparation/isolation of individual enantiomers
include chiral synthesis from a suitable optically pure precursor
or resolution of the racemate (or the racemate of a salt or
derivative) using, for example, chiral high pressure liquid
chromatography (HPLC). When the compounds described herein contain
olefinic double bonds or other centres of geometric asymmetry, and
unless specified otherwise, it is intended that the compounds
include both E and Z geometric isomers. Likewise, all tautomeric
forms are also intended to be included.
[0479] "Stable compound" and "stable structure" are meant to
indicate a compound that is sufficiently robust to survive
isolation to a useful degree of purity from a reaction mixture, and
formulation into an efficacious therapeutic agent.
[0480] By "statistically significant," it is meant that the result
was unlikely to have occurred by chance. Statistical significance
can be determined by any method known in the art. Commonly used
measures of significance include the p-value, which is the
frequency or probability with which the observed event would occur,
if the null hypothesis were true. If the obtained p-value is
smaller than the significance level, then the null hypothesis is
rejected. In simple cases, the significance level is defined at a
p-value of 0.05 or less.
[0481] "Substantially" or "essentially" includes nearly totally or
completely, for instance, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99% or
greater of some given quantity.
[0482] The term "secondary" refers to a condition or state that can
occur with another disease state, condition, or treatment, can
follow on from another disease state, condition, or treatment, or
can result from another disease state, condition or treatment. The
term also refers to situations where a disease state, condition, or
treatment can play only a minor role in creating symptoms or a
response in a patient's final diseased state, symptoms or
condition.
[0483] "Subjects" or "patients" (the terms are used interchangeably
herein) in need of treatment with a compound of the present
disclosure include, for instance, subjects "in need of phosphate
lowering." Included are mammals with diseases and/or conditions
described herein, particularly diseases and/or conditions that can
be treated with the compounds of the invention, with or without
other active agents, to achieve a beneficial therapeutic and/or
prophylactic result. A beneficial outcome includes a decrease in
the severity of symptoms or delay in the onset of symptoms,
modulation of one or more indications described herein (e.g.,
reduced phosphate ion levels in serum or blood of patients with or
at risk for hyperphosphatemia, increased fecal output of phosphate
ions in patients with or at risk for hyperphosphatemia), increased
longevity, and/or more rapid or more complete resolution of the
disease or condition.
[0484] A "stereoisomer" refers to a compound made up of the same
atoms bonded by the same bonds but having different
three-dimensional structures, which are not interchangeable. The
present invention contemplates various stereoisomers and mixtures
thereof and includes "enantiomers", which refers to two
stereoisomers whose molecules are nonsuperimposeable mirror images
of one another.
[0485] A "tautomer" refers to a proton shift from one atom of a
molecule to another atom of the same molecule. The present
invention includes tautomers of any said compounds.
[0486] A "therapeutically effective amount" or "effective amount"
includes an amount of a compound of the invention which, when
administered to a mammal, preferably a human, is sufficient to
inhibit or otherwise reduce the transport of phosphate ions from
the gastrointestinal lumen, increase fecal output of phosphate
ions, reduce serum levels of phosphate ions, treat
hyperphosphatemia in the mammal, preferably a human, and/or treat
any one or more other conditions described herein. The amount of a
compound of the invention which constitutes a "therapeutically
effective amount" will vary depending on the compound, the
condition and its severity, the manner of administration, and the
age of the mammal to be treated, but can be determined routinely by
one of ordinary skill in the art having regard to his own knowledge
and to this disclosure.
[0487] "Treating" or "treatment" as used herein covers the
treatment of the disease or condition of interest in a mammal,
preferably a human, having the disease or condition of interest,
and includes:
[0488] (i) preventing the disease or condition from occurring in a
mammal, in particular, when such mammal is predisposed to the
condition but has not yet been diagnosed as having it;
[0489] (ii) inhibiting the disease or condition, i.e., arresting
its development;
[0490] (iii) relieving the disease or condition, i.e., causing
regression of the disease or condition; or
[0491] (iv) relieving the symptoms resulting from the disease or
condition, i.e., relieving pain without addressing the underlying
disease or condition. As used herein, the terms "disease" and
"condition" may be used interchangeably or may be different in that
the particular malady or condition may not have a known causative
agent (so that etiology has not yet been worked out) and it is
therefore not yet recognized as a disease but only as an
undesirable condition or syndrome, wherein a more or less specific
set of symptoms have been identified by clinicians.
EXAMPLES
[0492] The following Examples, provided for purposes of
illustration, not limitation, illustrate various methods of making
compounds of this invention. It is understood that one skilled in
the art may be able to make these compounds by similar methods or
by combining other methods known to one skilled in the art. It is
also understood that one skilled in the art would be able to make,
in a similar manner as described below, other compounds of the
invention not specifically illustrated below by using the
appropriate starting components and modifying the parameters of the
synthesis as needed. In general, starting components may be
obtained from sources such as Sigma Aldrich, Lancaster Synthesis,
Inc., Maybridge, Matrix Scientific, TCI, and Fluorochem USA, etc.
or synthesized according to sources known to those skilled in the
art (see, e.g., Advanced Organic Chemistry: Reactions, Mechanisms,
and Structure, 5th edition (Wiley, December 2000)) or prepared as
described herein.
[0493] It will also be appreciated by those skilled in the art that
in the process described herein the functional groups of
intermediate compounds may need to be protected by suitable
protecting groups. Such functional groups include hydroxy, amino,
mercapto and carboxylic acid. Suitable protecting groups for
hydroxy include trialkylsilyl or diarylalkylsilyl (for example,
t-butyldimethylsilyl, t-butyldiphenylsilyl or trimethylsilyl),
tetrahydropyranyl, benzyl, and the like. Suitable protecting groups
for amino, amidino and guanidino include t-butoxycarbonyl,
benzyloxycarbonyl, and the like. Suitable protecting groups for
mercapto include --C(O)--R'' (where R'' is alkyl, aryl or
arylalkyl), p-methoxybenzyl, trityl and the like. Suitable
protecting groups for carboxylic acid include alkyl, aryl or
arylalkyl esters. Protecting groups may be added or removed in
accordance with standard techniques, which are known to one skilled
in the art and as described herein. The use of protecting groups is
described in detail in Green, T. W. and P. G. M. Wutz, Protective
Groups in Organic Synthesis (1999), 3rd Ed., Wiley. As one of skill
in the art would appreciate, the protecting group may also be a
polymer resin such as a Wang resin, Rink resin or a
2-chlorotrityl-chloride resin.
[0494] Furthermore, all compounds of the invention which exist in
free base or acid form can be converted to their pharmaceutically
acceptable salts by treatment with the appropriate inorganic or
organic base or acid by methods known to one skilled in the art.
Salts of the compounds of the invention can be converted to their
free base or acid form by standard techniques.
Example 1
Cell-Based Activity of NHE3 Inhibition and Inhibition of Intestinal
of Sodium and Phosphate Absorption
[0495] The compounds in Table E1, or pharmaceutically acceptable
salts thereof, below were tested in a cell-based assay of NHE3
inhibition under prompt conditions (prompt inhibition). These
compounds were also tested for the ability to inhibit sodium and
phosphate absorption in the intestinal lumen of rats.
TABLE-US-00005 TABLE E1 Cm pd. # Structure 1 ##STR00170## 2
##STR00171## 3 ##STR00172## 4 ##STR00173## 5 ##STR00174## 6
##STR00175## 7 ##STR00176## 8 ##STR00177## 9 ##STR00178## 10
##STR00179## 11 ##STR00180## 12 ##STR00181## 13 ##STR00182## 14
##STR00183## 15 ##STR00184## 16 ##STR00185## 17 ##STR00186## 18
##STR00187## 19 ##STR00188## 20 ##STR00189## 21 ##STR00190## 22
##STR00191## 23 ##STR00192## 24 ##STR00193## 25 ##STR00194## 26
##STR00195## 27 ##STR00196## 28 ##STR00197## 29 ##STR00198## 30
##STR00199## 31 ##STR00200## 32 ##STR00201## 33 ##STR00202## 34
##STR00203## 35 ##STR00204## 36 ##STR00205## 37 ##STR00206## 38
##STR00207## 39 ##STR00208## 40 ##STR00209## 41 ##STR00210## 42
##STR00211## 43 ##STR00212## 44 ##STR00213## 45 ##STR00214## 46
##STR00215## 47 ##STR00216## 48 ##STR00217## 49 ##STR00218## 50
##STR00219## 51 ##STR00220## 52 ##STR00221## 53 ##STR00222## 54
##STR00223## 55 ##STR00224## 56 ##STR00225## 57 ##STR00226## 58
##STR00227## 59 ##STR00228## 60 ##STR00229## 61 ##STR00230## 62
##STR00231## 63 ##STR00232## 64 ##STR00233## 65 ##STR00234## 66
##STR00235## 67 ##STR00236## 68 ##STR00237## 69 ##STR00238## 70
##STR00239## 71 ##STR00240## 72 ##STR00241## 73 ##STR00242## 74
##STR00243## 75 ##STR00244## 76 ##STR00245## 77 ##STR00246## 78
##STR00247## 79 ##STR00248## 80 ##STR00249## 81 ##STR00250## 82
##STR00251## 83 ##STR00252## 84 ##STR00253## 85 ##STR00254## 86
##STR00255## 87 ##STR00256## 88 ##STR00257## 89 ##STR00258## 90
##STR00259## 91 ##STR00260## 92 ##STR00261## 93 ##STR00262## 94
##STR00263## 95 ##STR00264## 96 ##STR00265## 97 ##STR00266## 98
##STR00267## 99 ##STR00268## 100 ##STR00269## 101 ##STR00270## 102
##STR00271## 103 ##STR00272## 104 ##STR00273## 105 ##STR00274## 106
##STR00275## 107 ##STR00276## 108 ##STR00277## 109 ##STR00278## 110
##STR00279## 111 ##STR00280## 112 ##STR00281## 113 ##STR00282## 114
##STR00283## 115 ##STR00284## 116 ##STR00285## 117 ##STR00286## 118
##STR00287## 119 ##STR00288## 120 ##STR00289## 121 ##STR00290## 122
##STR00291##
123 ##STR00292## 124 ##STR00293## 125 ##STR00294## 126 ##STR00295##
127 ##STR00296## 128 ##STR00297## 129 ##STR00298## 130 ##STR00299##
131 ##STR00300## 132 ##STR00301## 133 ##STR00302## 134 ##STR00303##
135 ##STR00304## 136 ##STR00305## 137 ##STR00306## 138 ##STR00307##
139 ##STR00308## 140 ##STR00309## 141 ##STR00310## 142 ##STR00311##
143 ##STR00312## 144 ##STR00313## 145 ##STR00314## 146 ##STR00315##
147 ##STR00316## 148 ##STR00317## 149 ##STR00318## 150 ##STR00319##
151 ##STR00320## 152 ##STR00321## 153 ##STR00322## 154 ##STR00323##
155 ##STR00324## 156 ##STR00325## 157 ##STR00326## 158 ##STR00327##
159 ##STR00328## 160 ##STR00329## 161 ##STR00330## 162 ##STR00331##
163 ##STR00332## 164 ##STR00333## 165 ##STR00334## 166 ##STR00335##
167 ##STR00336## 168 ##STR00337## 169 ##STR00338## 170 ##STR00339##
171 ##STR00340## 172 ##STR00341## 173 ##STR00342## 174 ##STR00343##
175 ##STR00344## 176 ##STR00345## 177 ##STR00346## 178 ##STR00347##
179 ##STR00348## 180 ##STR00349##
[0496] Cell-based activity under Prompt Conditions. Rat or human
NHE3-mediated Na.sup.+-dependent H.sup.+ antiport was measured
using a modification of the pH sensitive dye method originally
reported by Paradiso (PNAS USA. 81:7436-7440, 1984). Opossum kidney
(OK) cells were obtained from the ATCC and propagated per their
instructions. The rat NHE3 gene (GenBank M85300) or the human NHE3
gene (GenBank NM_004174.1) was introduced into OK cells via
electroporation, and cells were seeded into 96 well plates and
grown overnight. Medium was aspirated from the wells, cells were
washed twice with NaCl-HEPES buffer (100 mM NaCl, 50 mM HEPES, 10
mM glucose, 5 mM KCl, 2 mM CaCl.sub.2, 1 mM MgC.sub.2, pH 7.4),
then incubated for 30 min at room temperature with NH.sub.4C-HEPES
buffer (20 mM NH.sub.4Cl, 80 mM NaCl, 50 mM HEPES, 5 mM KCl, 2 mM
CaCl.sub.2, 1 mM MgCl.sub.2, pH 7.4) containing 5 .mu.M
bis(acetoxymethyl)
3,3'-(3',6'-bis(acetoxymethoxy)-5-((acetoxymethoxy)carbonyl)-3-oxo-3H-spi-
ro[isobenzofuran-1,9'-xanthene]-2',7'-diyl)dipropanoate
(BCECF-AM).
[0497] Cells were washed twice with Ammonium free, Na.sup.+-free
HEPES (100 mM choline, 50 mM HEPES, 10 mM glucose, 5 mM KCl, 2 mM
CaCl.sub.2, 1 mM MgCl.sub.2, pH 7.4) and incubated in the same
buffer for 10 minutes at room temperature to lower intracellular
pH. NHE3-mediated recovery of neutral intracellular pH was
initiated by addition of Na-HEPES buffer containing 0.4 .mu.M ethyl
isopropyl amiloride (EIPA, a selective antagonist of NHE-1 activity
that does not inhibit NHE3) and 0-30 .mu.M test compound, or a
pharmaceutically acceptable salt thereof, and monitoring the pH
sensitive changes in BCECF fluorescence (.lamda..sub.ex 505 nm,
.lamda..sub.em 538 nm) normalized to the pH insensitive BCECF
fluorescence (.lamda..sub.ex 439 nm, .lamda..sub.em 538 nm).
Initial rates were plotted as the average 2 or more replicates, and
pIC.sub.50 values were estimated using GraphPad Prism. The results
are summarized in Table E3 below.
[0498] Inhibition of intestinal sodium and phosphate absorption.
Urinary sodium concentration and fecal form were measured to assess
the ability of selected example compounds to inhibit the absorption
of sodium from the intestinal lumen. Eight-week old Sprague-Dawley
rats were purchased from Charles River Laboratories (Hollister,
Calif.), were housed 2 per cage, and acclimated for at least 3 days
before study initiation. Animals were fed Harlan Teklad Global 2018
rodent chow (Indianapolis, Ind.) and water ad libitum throughout
the study and maintained in a standard light/dark cycle of 6 AM to
6 PM. On the day of the study, between 4 PM and 5 PM, a group of
rats (n=6) were dosed via oral gavage with test compound, or a
pharmaceutically acceptable salt thereof, or vehicle (water) at a
volume of 10 mL/kg.
[0499] After dose administration animals were placed in individual
metabolic cages where they were also fed the same chow in meal form
and watered ad libitum. At 16h post-dose, the urine samples were
collected and fecal form was assessed by two independent
observations. Fecal forms were scored according to a common scale
associated with increasing fecal water to the wettest observation
in the cage's collection funnel (1, normal pellet; 2, pellet
adhering to sides of collection funnel due to moisture; 3, loss of
normal pellet shape; 4, complete loss of shape with a blotting
pattern; 5, liquid fecal streams evident). A rat's fecal form score
(FFS) was determined by averaging both observational scores for all
rats within group (n=6). The vehicle group average was 1.
[0500] For urine samples, the volumes were determined
gravimetrically and centrifuged at 3,600.times.g. The supermatants
were diluted 100-fold in deionized Milli-Q water then filtered
through a 0.2 .mu.m GHP Pall AcroPrep filter plate (Pall Life
Sciences, Ann Arbor, Mich.) prior to analysis by ion
chromatography. Ten microliters of each filtered extract was
injected onto a Dionex ICS-3000 ion chromatograph system (Dionex,
Sunnyvale, Calif.). Cations were separated by anisocratic method
using 25 mM methanesulfonic acid as the eluent on an on Pac CS12A 2
mm i.d..times.250 mm, 8 .mu.m particle size cation exchange column
(Dionex). Sodium was quantified using standards prepared from a
cation standard mix containing Li.sup.+, Na.sup.+, NH.sub.4.sup.+,
K.sup.+, Mg.sup.2+, and Ca.sup.2+ (Dionex). The mean mass of sodium
urinated for every group in the 16 h period was determined with the
vehicle group usually urinating approximately 21 mg sodium. The
urine Na (uNa) for rats in the test groups were expressed as a
percentage of the vehicle mean and the means were compared to that
of the vehicle group by utilizing a one-way analysis of variance
coupled with a Dunnett's post hoc test. The results are shown in
Table E3 below.
TABLE-US-00006 Prompt Rat Prompt Human Dose Urine Na % Urine P % of
Fecal Form No. of trials Cmpd # NHE3 pIC.sub.50 NHE3 pIC.sub.50
mg/kg of control control Score average averaged 1 6.60 10 87% 52% 1
2 6.70 6.50 10 115% 80% 1 3 7.40 7.60 1 41% 57% 1 4 6.90 6.80 10
84% 106% 1 5 6.90 7.85 10 51% 65% 1 30 23% 105% 2 6 8.35 8.30 1 21%
46% 2 7 6.30 7.20 10 76% 90% 1 8 6.90 6.40 10 73% 101% 1 30 31%
114% 2 9 6.50 7.10 10 56% 77% 1 10 6.65 7.50 10 76% 80% 1 11 6.95
6.80 10 60% 64% 1 30 29% 96% 2 12 6.10 7.00 10 82% 94% 1 13 6.70
7.40 10 74% 56% 1 14 7.00 7.60 10 51% 59% 1 15 7.30 7.90 10 77% 65%
1 16 6.70 7.80 30 87% 123% 1 17 7.10 6.60 30 86% 120% 1 18 7.25
7.35 10 74% 142% 1 18 6.90 6.90 30 41% 109% 1 19 7.00 7.40 10 72%
119% 1 20 7.30 7.20 10 86% 81% 1 21 6.10 7.00 10 66% 101% 1 22 7.34
6.95 1 91% 64% 1 10 19% 40% 2 2 23 6.87 8.55 10 73% 95% 1 2 24 7.68
8.58 10 100% 80% 1 30 27% 70% 3 25 6.85 6.60 10 87% 150% 1 26 7.50
7.70 10 78% 77% 1 27 7.50 8.40 10 51% 91% 1 2 28 7.60 8.10 10 83%
129% 1 29 7.50 8.10 10 92% 102% 1 30 7.80 8.40 10 100% 104% 1 31
7.70 7.70 10 96% 81% 1 32 7.30 8.40 10 128% 122% 1 33 7.40 7.90 10
98% 117% 1 34 7.90 8.20 10 76% 72% 1 35 8.00 8.30 10 65% 57% 1 36
7.60 8.00 10 85% 86% 1 37 7.50 7.50 10 63% 101% 1 38 5.50 5.60 10
101% 120% 1 39 7.30 1 71% 166% 1 10 68% 130% 1 40 <5.00 <5.00
1 80% 149% 1 10 90% 128% 1 41 7.90 8.20 10 104% 133% 1 42 7.70 8.20
10 94% 94% 1 43 7.50 7.70 10 70% 101% 1 44 7.70 7.90 10 88% 102% 1
45 7.50 7.90 10 97% 109% 1 46 7.80 7.90 10 58% 112% 1 47 7.30 7.80
10 73% 51% 1 48 7.55 7.10 10 68% 55% 1 49 7.65 7.40 10 38% 77% 1 50
7.45 7.60 10 82% 50% 1 51 7.40 7.90 10 79% 52% 1 52 7.35 7.40 10
68% 71% 1 53 7.45 7.40 10 100% 59% 1 54 7.30 7.50 10 75% 72% 1 55
7.70 7.90 10 85% 45% 1 56 6.90 7.00 10 15% 50% 2 57 7.10 7.50 10
25% 75% 3 58 6.30 7.30 10 82% 68% 1 59 6.90 7.30 10 18% 45% 2 60
6.35 7.10 10 67% 92% 1 61 7.00 7.80 1 93% 96% 1 3 50% 70% 1 10 21%
67% 3 62 <5.00 7.25 10 121% 77% 1 63 7.20 8.00 10 51% 95% 1 64
7.40 8.20 10 34% 66% 1 65 8.85 8.00 10 93% 85% 1 66 8.35 8.35 10
35% 30% 1 67 8.00 8.70 10 4% 67% 2 68 <5.00 <5.00 10 70% 97%
1 69 6.60 6.70 10 82% 78% 1 70 6.70 7.20 10 96% 83% 1 71 6.50 7.00
10 80% 40% 1 72 8.30 8.25 1 82% 99% 1 3 74% 115% 2 10 33% 43% 1 73
5.30 6.30 10 74% 49% 2 74 6.30 6.80 10 30% 44% 3 75 6.30 6.90 10
81% 55% 1 76 5.60 6.40 1 58% 96% 1 3 40% 89% 2 10 12% 61% 3 77 6.25
7.35 1 80% 82% 2 3 36% 79% 2 2 10 17% 41% 4 78 6.00 6.50 10 53% 39%
2 79 6.50 7.20 1 65% 109% 1 3 44% 81% 2 10 17% 33% 3 80 5.50 6.93 1
66% 70% 1 3 55% 39% 2 2 10 9% 21% 3 81 7.90 7.90 10 11% 42% 2 82
6.80 7.10 10 47% 69% 1 83 <5.00 <5.00 10 82% 59% 1 84 7.50
7.70 8 7% 47% 3 85 5.80 6.10 10 92% 85% 1 86 5.80 5.90 10 87% 89% 1
87 <5.00 8.20 3 54% 29% 1 88 7.07 7.93 1 84% 77% 1 2 3 22% 75% 3
3 10 21% 69% 5 89 7.10 7.90 2.5 55% 50% 2 10 49% 117% 3 90 7.20
7.85 1 76% 65% 1 3 30% 58% 1 10 38% 20% 5 91 5.30 <5.00 10 77%
56% 1 92 <5.00 10 62% 70% 1 93 <5.00 10 78% 75% 1 94 <5.00
5.60 10 67% 66% 1 95 6.60 7.00 10 38% 111% 2 96 7.50 8.30 10 33%
94% 1 97 7.60 8.50 10 64% 78% 1 98 8.40 8.10 10 83% 88% 1 99 8.60
5.00 10 41% 52% 1 100 8.10 8.30 10 57% 68% 1 101 <5.00 8.10 10
64% 81% 1 102 6.60 10 86% 92% 1 103 6.70 10 40% 71% 1 104 6.70 10
56% 62% 2 105 5.90 3 119% 154% 1 106 7.00 7.90 1 98% 124% 1 3 76%
39% 2 10 20% 64% 4 107 6.90 8.10 1 88% 106% 1 3 55% 66% 1 10 28%
59% 4 108 8.40 3 13% 51% 4 109 7.40 8.10 1 64% 65% 1 3 52% 51% 2 10
28% 52% 4 110 5.80 3 63% 68% 1 111 <5.00 10 60% 69% 2 112
<5.00 10 73% 67% 1 113 <5.00 <5.00 10 64% 61% 1 114
<5.00 <5.00 10 45% 100% 3 115 <5.00 8.55 10 69% 60% 1 116
<5.00 8.30 10 84% 130% 1 117 7.50 8.20 10 77% 98% 1 118 7.40
8.10 10 83% 131% 1 119 8.70 7.80 10 43% 52% 1 120 7.80 3 71% 71% 1
121 <5.00 3 92% 151% 1 122 6.20 6.80 3 30% 87% 2 123 7.50 7.80 1
49% 124% 1 2 3 12% 88% 3 3 124 7.17 7.50 1 69% 154% 1 3 22% 61% 2 2
125 <5.00 10 81% 278% 1 126 <5.00 6.55 10 93% 94% 1 127 8.20
8.30 1 55% 159% 1 2 3 39% 62% 1 4 10 9% 53% 1 128 7.10 8.00 1 46%
90% 1 2 3 35% 58% 2 4 129 5.60 6.90 3 16% 48% 2 130 6.10 7.20 3 18%
70% 2 131 6.10 7.20 3 38% 68% 2 132 6.00 7.70 3 65% 88% 1 133 6.50
7.30 3 23% 67% 2 134 6.50 6.50 3 64% 72% 1 135 7.40 8.45 1 100% 92%
1 3 94% 44% 1 10 58% 85% 2 136 <5.00 7.70 10 104% 93% 1 137 7.30
7.30 1 39% 137% 1 3 28% 139% 3 2 138 7.30 7.30 3 37% 78% 2 139 7.60
7.80 1 80% 63% 1 3 27% 45% 3 2 140 8.90 7.70 10 110% 121% 1 141
6.90 7.40 3 63% 24% 2 142 8.10 7.10 3 45% 38% 2 143 7.25 7.27 1 68%
73% 1 3 34% 93% 3 3 144 7.20 7.77 3 32% 47% 2 2 145 7.60 7.70 3 41%
51% 3 146 7.80 8.35 3 70% 58% 2 147 7.00 7.67 3 40% 32% 2 3 148
8.40 7.80 3 49% 146% 1 149 8.10 8.00 1 54% 122% 1 2 53% 69% 2 3 46%
115% 1 2 150 8.60 8.00 3 73% 74% 1 10 12% 159% 1 151 8.30 7.50 3
78% 52% 1 10 42% 121% 2 152 <5.00 8.70 10 26% 74% 1 153 6.90
7.50 3 28% 84% 3 154 6.80 6.80 3 112% 65% 1 155 7.70 7.90 3 40% 44%
2 156 6.70 7.20 3 13% 67% 3 157 7.70 7.77 3 26% 50% 3 3 158
<5.00 6.90 3 32% 64% 2 159 7.20 7.30 3 27% 55% 2 160 7.70 10
108% 77% 1 161 9.20 7.60 3 82% 60% 2 162 7.30 6.60 2 130% 50% 2 163
7.90 7.60 3 27% 48% 2 164 7.53 8.13 3 18% 63% 3 2 165 <5.00 8.20
10 104% 68% 1 166 <5.00 8.40 10 111% 43% 1 167 5.80 8.37 3 36%
99% 2 168 7.35 8.13 3 56% 50% 1 169 6.50 6.20 3 42% 64% 2 170 7.10
7.20 3 31% 34% 2 171 8.20 10 49% 49% 1 172 8.20 7.10 3 26% 42% 2
173 7.60 8.10 2.5 64% 69% 2 174 8.60 8.53 3 37% 55% 1 10 49% 61% 1
175 7.80 7.40 3 102% 48% 1 176 7.50 7.40 3 73% 92% 1 177 7.70 7.80
3 52% 45% 2 178 7.10 7.33 3 18% 46% 3 179 8.00 7.77 3 40% 66% 1 180
8.03 8.30 0.03 67% 80% 1 0.1 45% 82% 1 0.3 33% 75% 3 1 15% 69% 3 38
3 53% 38% 4
Example 2
Cell-Based Assay of NHE3 Activity Under Prompt and Persistent
Conditions
[0501] The compounds in Table E4 below, or a pharmaceutically
acceptable salt thereof, were tested in a cell-based assay of NHE3
inhibition under prompt conditions (prompt inhibition) and
persistent conditions (persistent inhibition). These compounds were
also tested in a cell-based assay of NaP2b activity.
TABLE-US-00007 TABLE E4 Cmpd. Structure Cpd 001 (same as #3 in
Table E3) ##STR00350## Cpd 002 (same as #180 in Table E3)
##STR00351## Cpd 003 ##STR00352## Cpd 004 (same as #40 in Table E3)
##STR00353## Cpd 005 (same as #39 in Table E3) ##STR00354##
[0502] Cell-based activity of NHE3 Activity under `Prompt`
Conditions. This assay was performed as described in Example 1
(supra).
[0503] Cell-based activity of NHE3 Activity under `Persistent`
Conditions. The ability of compounds to inhibit Rat NHE3-mediated
Na.sup.+-dependent H+ antiport after application and washout was
measured using a modification of the pH sensitive dye method
described above. Opossum kidney (OK) cells were obtained from the
ATCC and propagated per their instructions. The rat NHE3 gene was
introduced into OK cells via electroporation, and cells were seeded
into 96 well plates and grown overnight. Medium was aspirated from
the wells, cells were washed twice with NaCl-HEPES buffer (100 mM
NaCl, 50 mM HEPES, 10 mM glucose, 5 mM KCl, 2 mM CaC.sub.2, 1 mM
MgC.sub.2, pH 7.4), then overlayed with NaCl-HEPES buffer
containing 0-30 .mu.M test compound.
[0504] After a 60 min incubation, the test drug containing buffer
was aspirated from the cells, cells were washed twice with
NaCl-HEPES buffer without drug, then incubated for 30 min at room
temperature with NH.sub.4Cl-HEPES buffer (20 mM NH.sub.4Cl, 80 mM
NaCl, 50 mM HEPES, 5 mM KCl, 2 mM CaCl.sub.2, 1 mM MgCl.sub.2, pH
7.4) containing 5 uM BCECF-AM. Cells were washed twice with
Ammonium free, Na.sup.+-free HEPES (100 mM choline, 50 mM HEPES, 10
mM glucose, 5 mM KCl, 2 mM CaC.sub.2, 1 mM MgC.sub.2, pH 7.4) and
incubated in the same buffer for 10 minutes at room temperature to
lower intracellular pH. NHE3-mediated recovery of neutral
intracellular pH was initiated (40 min after compound washout) by
addition of Na-HEPES buffer containing 0.4 uM ethyl isopropyl
amiloride (EIPA, a selective antagonist of NHE-1 activity that does
not inhibit NHE3), and monitoring the pH sensitive changes in BCECF
fluorescence (.lamda..sub.ex 505 nm, .lamda..sub.em 538 nm)
normalized to the pH insensitive BCECF fluorescence (.lamda..sub.ex
439 nm, .lamda..sub.em 538 nm). Initial rates were plotted as the
average 2 or more replicates, and pIC.sub.50 values were estimated
using GraphPad Prism.
[0505] Cell-based assay of NaP2b activity. The rate of phosphate
(Pi) uptake into cells was measured using a modification of a
literature method (see Mohrmann et al. Am. J Phys. 250(3 pt
1):G323-30, 1986). Briefly, HEK293 cells were transiently
transfected with an expression clone encoding either rat or human
NaP2b. The next day, transfected cells were treated with a
pharmacological agent to minimize endogenous PiT-mediated phosphate
transport activity, such that the only remaining sodium-dependent
phosphate transport activity is that which was bestowed by
introduction of the NaP2b gene. Cells were incubated with
radioactive inorganic phosphate in the presence or absence of
varying concentrations of test compound. After a short time, cells
were washed, harvested, and the amount of hot phosphate taken up in
the cells determined by liquid scintillation counting.
[0506] HEK293 cells were obtained from the American Type Culture
collection and propagated per their instructions. Expression clones
for rat and human NaP2b (SLC34A2) were obtained from Open
Biosystems (Catalog numbers MRN1768-9510282, and MHS1010-99823026,
respectively). There are two putative splice variants of human
NaP2b, designated as isoform a and isoform b (NCBI Reference
Sequences: NP_006415.2 and NP_001171470.1, respectively). The
sequence of the open reading from in MHS1010-99823026 corresponds
to isoform b; transfection with this construct was found to confer
only very low levels of nonendogenous Pi transport activity. The
cDNA was therefore mutated to correspond with isoform a;
transfection with this sequence conferred Pi transport
significantly over background. Thus, studies of the inhibition of
human NaP2b used isoform a exclusively.
[0507] Cells were seeded into 96-well plates at 25,000 cells/well
and cultured overnight. Lipofectamine 2000 (Invitrogen) was used to
introduce the NaP2b cDNA, and the cells were allowed to approach
confluence during a second overnight incubation. Medium was
aspirated from the cultures, and the cells were washed once with
choline uptake buffer (14 mM Tris, 137 mM choline chloride, 5.4 mM
KCl, 2.8 mM CaCl.sub.2), 1.2 mM MgSO4, 100 uM KH2PO4, 1 mg/mL
Bovine Serum Albumin, pH 7.4). Cells were then overlayed with
either choline uptake buffer or sodium uptake buffer (14 mM Tris,
137 mM sodium chloride, 5.4 mM KCl, 2.8 mM CaCl.sub.2), 1.2 mM
MgSO4, 100 uM KH2PO4, PiT-silencing agent, 1 mg/mL Bovine Serum
Albumin, pH 7.4) containing 6-9 uCi/mL .sup.33P orthophosphoric
acid (Perkin Elmer) and test compound. Each compound was tested at
twelve concentrations ranging from 0.1 nM to 30 uM. Assays were run
in duplicate and compounds of interest were tested multiple times.
After incubation for 23 minutes at room temperature, assay mixtures
were removed, and the cells were washed twice with ice cold stop
solution (137 mM sodium chloride, 14 mM Tris, pH 7.4). Cells were
lysed by addition of 20 .mu.L 0.1% Tween 80 followed by 100 .mu.L
scintillation fluid, and counted using a TopCount (Perkin Elmer).
The pIC50 (the negative log of the IC50) values of the test
compounds were calculated using GraphPad Prism. Preliminary studies
showed that under these conditions, sodium-dependent Pi uptake was
linear for at least 30 minutes and tolerated 0.6% (v/v) DMSO
without deleterious effects. The results are summarized in Table E5
below.
TABLE-US-00008 TABLE E5 Rat NHE3 Human NHE3 pIC.sub.50 pIC.sub.50
pIC.sub.50 pIC.sub.50 pIC.sub.50 Human Compound Prompt Persistent
Prompt Persistent Nap2B 001.sup.a 7.6 nd 7.4 nd nd 002.sup.b 8 8.4
8 8.2 <4.5 003.sup.b 8.6 nd 8 8.1 nd 004.sup.b 7.3 5.6 7.3 5.6
nd 005.sup.b <5.0 nd <5.0 nd nd .sup.aCompound 001tested as
free base. .sup.bCompounds 002, 003 004 and 005 were tested as the
dihydrochloride salt
[0508] Further experiments were performed to test the compounds
under the persistent and prompt conditions described above, and to
test their effects on urinary excretion of sodium in rats. The
latter was performed by orally dosing the compounds in rats (single
dose) and measuring urinary Na excretion (as a % of vehicle). The
results are indicated as percentage of urinary sodium (UNa %); low
values indicate relatively active compounds. The results are shown
in Table E6 below.
TABLE-US-00009 TABLE E6 pIC.sub.50 pIC.sub.50 Compound Prompt
Persistent UNa (%) 001.sup.a 7.4 nd 41 @ 1 mg/kg 002.sup.b 8 8.2 11
@ 1 mg/kg 003.sup.b 8 8.1 22 @ 1 mg/kg 004.sup.b 7.3 5.6 68 @ 10
mg/kg 005.sup.b <5.0 nd 90 @ 10 mg/kg .sup.aCompound 001tested
as free base. .sup.bCompounds 002, 003, 004 and 005 were tested as
the dihydrochloride salt
[0509] These results identified compounds 002 and 003 as persistent
inhibitors of NHE3-mediated Na.sup.+-dependent H.sup.+ antiport,
and compound 004 as a non-persistent inhibitor of NHE3-mediated
Na.sup.+-dependent H.sup.+ antiport. Compound 005 was considered
inactive.
Example 3
Pharmacodynamic Studies with .sup.33P Oral Challenge in Normal
Function Rats
[0510] The compounds identified as Cpds 003, 004, and 005 (from
Table E4, as their dihydrochloride salts) were tested for the
ability to block intestinal phosphate uptake in rats. Rats were
orally challenged with dosing solutions composed of 5 ml/kg (1.3
ml) of 8 mM Pi with .sup.33P and +/-10 mg/kg of test compound. Also
included were dosing solutions further composed of either (i) 75 mM
glucose+4 mM Ca or (ii) 4 mM Ca.
[0511] The results are shown in FIGS. 1A-1C. FIG. 1A shows that Cpd
004, a non-persistent NHE3 inhibitor (i.e., with no significant
effect on urinary Na and fecal form), was as potent at reducing Pi
uptake as a persistent inhibitor such as Cpd 003 (i.e., inducing a
significant reduction in UNa, and change in fecal form). Cpd 005
was inactive in this assay. FIGS. 1B-C show that Cpd 003
significantly reduced Pi uptake in the presence of glucose/Ca (1B)
and Ca (1C).
Example 4
Effects in a Rat Model of Uremia-Associated Vascular
Calcification
[0512] Chronic kidney disease (CKD) has multiple pathogenic
mechanisms, and advanced CKD is often characterized by disordered
mineral metabolism (e.g., hyperphosphatemia, hypercalcemia) and
vascular calcification. Studies were thus performed to test the
effectiveness of the dihydrochloride salt of Cpd 002 (from Table
E4, as the dihydrochloride salt) in a uremic rat model of CKD
featuring vascular calcification. This model is characterized by
renal insufficiency and regular active Vitamin D.sub.3
administration to promote hyperphosphatemia and vascular
calcification (see Lopez et al., J. Am. Soc. Nephrol. 17:795-804,
2006). The study utilized Spraque-Dawley rats treated as follows:
.sup.th nephrectomy by excision; regular calcitriol administration
(active vitamin D.sub.3) 80 ng/kg i.p. 3/week; and fed a purified
0.9% P diet (inorganic phosphorus).
[0513] Rats were stratified into two experimental groups by serum
creatinine levels of 0.8 to 1.5 mg/dl and body weight, fed
drug-in-chow with powdered vehicle diet or the same diet with Cpd
002 (0.065 mg/g chow) mixed-in, and monitored for weekly body
weight and selected serum parameters, daily clinical observations,
and endpoint calcification. The study design is illustrated in FIG.
2.
[0514] Selected experimental groups were fed vehicle (n=12) or Cpd
002 (n=12) at enrollment (day 0). As shown in FIGS. 3A-F, initial
body weights and selected serum parameters such as serum
phosphorus, serum calcium, serum creatinine, and blood urea
nitrogen were comparable for both groups.
[0515] Selected endpoint plasma parameters from day 27 are shown in
FIGS. 4A-F. These data show reduced plasma creatinine, reduced
plasma phosphorus, and reduced plasma FGF-23.
[0516] Endpoint heart and kidney remnant weights are shown in FIG.
5. These data show that hypertrophy of the heart and kidney
remnants was lessened in Cpd 002 treated rats. Given reduced plasma
creatinine, these results suggest that the kidney remnant in Cpd
002 treated rats has more functionality with less mass.
[0517] Endpoint creatinine clearance (C.sub.Cr) and plasma
aldosterone levels are shown in FIGS. 6A-B. These results suggest
that treatment with Cpd 002 protected against loss of kidney
function, and aldosterone increase suggests some volume depletion,
which is consistent with lower Na intake.
[0518] Endpoint vascular and soft tissue calcification is shown in
FIGS. 7A-B. These data shown that treatment with Cpd 002 reduced
calcium and phosphorus in the stomach, which is particularly
sensitive to calcification, and also reduced vascular calcification
as measured by aortic mineral content.
[0519] Overall, Cpd 002 was shown to improve kidney function,
reduce both heart hypertrophy and renal hypertrophy, exhibit
anti-hyperphosphatemic effects, and reduce associated vascular
calcification. These effects and decreased moribundity were
observed in the treatment group with a trend toward improved
mortality outcome. While the benefits from treatment with Cpd 002
can partly result from its effect on fluid overload and
hemodynamics, because vascular calcification in this model is
highly sensitive to dietary phosphate, the reduction in ectopic
calcification points to a reduction in phosphate absorption.
Example 5
Effects in an Adenine-Induced Uremic Rat Model
[0520] The effects of Cpd 002 (from Table E4, as the
dihydrochloride salt) were tested in an adenine-induced uremic rat
model. Rats were fed a diet including 0.75% adenine and 1.2%
phosphorus during the nephritis induction phase. The basal diet
during the treatment phase was normal chow including 0.3% adenine
and 0.6% phosphorus for 2 weeks. The rats were pair-fed the first 5
days (groups 1 and 2 to group 3, 4 days apart), and fed ad libitum
afterwards. The treatment groups were as follows: vehicle, n=10;
Cpd 002, 2 mg/kg/day drug-in-chow, n=10; and Cpd 002, 5 mg/kg/day
drug-in-chow, n=12. Weekly measurements were taken for serum
markers and kidney function. The study design is illustrated in
FIG. 8A.
[0521] As shown in FIGS. 8B-C, Cpd 002 reduced serum phosphorus and
serum creatinine at early time points. Here, this adenine-induced
model is considered an acute renal injury characterized by a
progressive recovery of renal function. Hence, the effects at early
time points are significant.
[0522] Organ weight collection data from week three is shown in
FIGS. 9A-B, and tissue mineralization data from week three is shown
in FIGS. 10A-B. These data show that treatment with Cpd 002 in this
model showed a trend towards lesser heart and kidney remodeling,
and a trend towards reduced heart and kidney calcification at the
highest dose.
Example 6
Effect on Renal Insufficiency with High Salt Feed in Nephrectomized
Rats
[0523] The effects of Cpd 002 (from Table E4, as the
dihydrochloride salt) were tested in a dietary salt-induced,
partial renal ablation model of CKD. The study design is
illustrated in FIG. 11A (12 rats per group). FIG. 11B shows the
effects of Cpd 002 on urinary excretion of phosphorus. In this
study, Cpd 002 improved blood pressure, fluid overload,
albuminuria, and heart and kidney hypertrophy, and also
significantly reduced phosphorus urinary excretion. These data
suggest an additive contribution for the phosphorus lowering effect
of Cpd 002 on improvements in the renal and vascular functions.
Example 7
Effects on Urinary Excretion of Phosphate and Calcium in Rats
[0524] The activity of Cpd 002 (from Table E4, as the
dihydrochloride salt) was tested for its effects on phosphorus and
calcium levels in the urine of rats. Rats were dosed according to
the schedule in Table E7.
TABLE-US-00010 TABLE E7 929uP Dose #2 groups Dose #1 10 min later 1
Water Water 2 Renvela .RTM. (sevelamer), 48 mg/kg Water 3 Water Cpd
002, 0.1 mg/kg 4 Water Cpd 002, 0.3 mg/kg 5 Water Cpd 002, 1.0
mg/kg 6 Water Cpd 002, 3.0 mg/kg
[0525] The rats were kept for 16 hours overnight (in the dark, the
typical feeding period) in individual metabolic cages, and urine
was collected the following morning for analysis of phosphate and
calcium levels. The study design is shown in FIG. 12. The results
are shown in FIGS. 13A-D. These results show that Cpd 002 reduced
both urine phosphorus mass and urine calcium mass relative to the
vehicle-only control. Increasing dosages of Cpd 002 also
significantly reduced urine phosphorus mass relative to 48 mg/kg
Renvela.RTM..
Example 8
Evaluation of Activity in the Reduction of Dietary Phosphorus at
Dose 15, 30 and 60 mg BID in a 7-Day Repeat Dose Study in Healthy
Volunteers
[0526] A Phase 1, single-center, randomized, double-blind,
placebo-controlled study was designed to evaluate the safety,
tolerability, and pharmacodynamic activity (PD) on sodium and
phosphorus excretion of different dosing regimens of Cpd 002, as
the dihydrochloride salt, (see Table E4) in healthy male and female
subjects.
[0527] Subjects were screened within 3 weeks prior to enrollment
and were allocated sequentially to cohorts in their order of
completing screening assessments. Each cohort of 15 subjects
checked into the clinical pharmacology unit (CPU) on Day -5 before
dinner. Subjects were confined to the CPU, Na+-standardized meals
(1500 mg/meal) provided.
[0528] In each cohort, 12 subjects were randomized to receive Cpd
002 and 3 subjects to placebo. Subjects received doses of Cpd 002
with approximately 240 mL of non-carbonated water on Days 1 to 7
(just prior to the appropriate meals, depending on twice daily
[bid, breakfast, dinner]. Subjects were provided standardized meals
within 10 minutes after dosing.
[0529] Selection of Study Population--Inclusion Criteria. Subjects
were eligible for inclusion in the study if they met all of the
following criteria:
[0530] 1. Healthy man or woman aged 19 to 65 years, inclusive.
[0531] 2. Body mass index (BMI) between 18 and 29.9 kg/m.sup.2,
inclusive.
[0532] 3. No clinically significant abnormalities in medical
history, physical examination, or clinical laboratory evaluations
at screening.
[0533] 4. Able to understand and comply with the protocol.
[0534] 5. Willing and able to sign informed consent.
[0535] 6. Females were non-pregnant, non-lactating, and either
postmenopausal for at least 12 months, as confirmed by
follicle-stimulating hormone (FSH) test, surgically sterile (e.g.,
tubal ligation, hysterectomy, bilateral oophorectomy with
appropriate documentation) for at least 90 days, or agreed to use
from the time of signing the informed consent until 45 days after
end of study 1 of the following forms of contraception:
intrauterine device with spermicide, female condom with spermicide,
contraceptive sponge with spermicide, diaphragm with spermicide,
cervical cap with spermicide, male sexual partner who agrees to use
a male condom with spermicide, sterile sexual partner, abstinence,
an intravaginal system (e.g., NuvaRing.RTM.) with spermicide, or
oral, implantable, transdermal, or injectable contraceptives with
spermicide.
[0536] 7. Males were either sterile, abstinent, or agreed to use,
from check-in until 45 days from final study visit, 1 of the
following approved methods of contraception: a male condom with
spermicide; a sterile sexual partner; use by female sexual partner
of an intrauterine device with spermicide, a female condom with
spermicide, contraceptive sponge with spermicide, an intravaginal
system (e.g., NuvaRing), a diaphragm with spermicide, a cervical
cap with spermicide, or oral, implantable, transdermal, or
injectable contraceptives).
[0537] Selection of Study Population--Exclusion Criteria. Subjects
were excluded from the study if they met any of the following
criteria:
[0538] 1. Diagnosis or treatment of any clinically symptomatic
biochemical or structural abnormality of the gastrointestinal
system.
[0539] 2. Any surgery on the small intestine or colon, excluding
appendectomy or cholecystectomy.
[0540] 3. Clinical evidence of significant cardiovascular,
respiratory, renal, hepatic, gastrointestinal, hematologic,
metabolic, endocrine, neurologic, psychiatric disease, or any
condition that may interfere with the subject successfully
completing the trial.
[0541] 4. Loose stools (BSFS of 6 or 7).gtoreq.2 days in the past 7
days.
[0542] 5. Hepatic dysfunction (alanine aminotransaminase [ALT] or
aspartate aminotransaminase [AST])>1.5 times the upper limit of
normal [ULN]) or renal impairment (serum creatinine>ULN).
[0543] 6. Clinically significant laboratory results at screening as
determined by the Investigator.
[0544] 7. Any evidence of or treatment of malignancy, excluding
non-melanomatous malignancies of the skin.
[0545] 8. If, in the opinion of the Investigator, the subject was
unable or unwilling to fulfill the requirements of the protocol or
had a condition that rendered the results uninterpretable.
[0546] 9. A diet, which in the opinion of the Investigator, could
have impacted the results of the study.
[0547] 10. Use of diuretic medications; medications that were known
to affect stool consistency and/or gastrointestinal motility,
including fiber supplements (unless required by study),
anti-diarrheals, cathartics, antacids, opiates, narcotics,
prokinetic drugs, enemas, antibiotics, probiotic medications or
supplements; or salt or electrolyte supplements containing Na+,
potassium, chloride, or bicarbonate formulations from CPU check in
(Day -5) to CPU check out (Day 9).
[0548] 11. Use of an investigational agent within 30 days prior to
Day -5.
[0549] 12. Positive virology (active hepatitis B infection [HBsAg],
hepatitis C infection [HCV], or human immunodeficiency virus
[HIV]), alcohol, or drugs of abuse test during screening,
[0550] 13. Use of any prescription medication within 7 days before
admission to the CPU, or required chronic use of any prescription
or non-prescription medication, with the exception of hormonal
replacement therapy (HRT) for postmenopausal women and hormonal
contraceptives.
[0551] 14. History of tobacco use, alcohol abuse, illicit drug use,
significant mental illness, physical dependence to any opioid, or
any history of drug abuse or addiction within 12 months of study
enrollment.
[0552] 15. Had significant blood loss (>450 mL) or had donated 1
or more units of blood or plasma within 8 weeks prior to study
entry.
[0553] Removal of Subjects from Therapy or Assessment. Subjects
were free to discontinue the study at any time, for any reason, and
without prejudice to further treatment. The Investigator could have
removed a subject if, in the Investigator's judgment, continued
participation posed unacceptable risk to the subject or to the
integrity of the study data. Subjects who withdrew early could have
been replaced, pending discussion with the Sponsor.
[0554] Efficacy evaluation--demographic and other baseline
characteristics. All subjects enrolled in the study received study
treatment and all had at least 1 post-baseline PD assessment.
[0555] An overview of the demographic characteristics of the
subjects enrolled in the study overall and by cohort is provided in
Table E8 below. Some variability was observed across cohorts
(especially in terms of gender and race); however, the baseline
characteristics of most cohorts mirrored that of the total
population.
[0556] No clinically significant abnormal findings were noted for
any subject during the physical examination performed at
screening.
TABLE-US-00011 TABLE E8 Demographic and Baseline Characteristics
Cohort 1 Cohort 3 Cohort 4 30 mg bid 60 mg bid 15 mg bid Parameter
(n = 12) (n = 12) (n = 12) Mean (SD) 38.8 (16.49) 37.8 (11.78) 38.7
(12.91) Median 31.0 33.5 36.5 Min Max 20, 63 22, 61 20, 60 Female 3
(25.0) 3 (25.0) 2 (16.7) Male 9 (75.0) 9 (75.0) 10 (83.3) Mean (SD)
73.7 (11.39) 79.3 (9.98) 78.7 (12.99) Median 71.7 75.7 79.7 MM, Max
58, 91 67, 103 60, 101 Mean (SD) 24.6 (2.69) 26.1 (2.46) 25.7
(2.87) Median 24.3 26.2 25.9 MM, Max 19, 29 22, 29 20, 30 Asian 1
(8.3) 1 (8.3) 0 Black 2 (16.7) 6 (50.0) 4 (33.3) White 7 (58.3) 5
(41.7) 6 (50.0) Other 2 (16.7) 0 1 (8.3) Missing 0 0 1 (8.3)
[0557] The schedule of events for screening and treatment period is
provided in Table E9 below.
TABLE-US-00012 TABLE E9 Screening and Baseline Day Double-blind
Treatment Period Day Follow-up Procedure -26 to -5 -5.sup.a -4 -3
-2 -1 1 2 3 4 5 6 7 8 9.sup.a 23 .+-. 2 Informed X consent
Inclusion/ X X.sup.b exclusion Medical X X.sup.b history Physical X
X examination Vital signs X X X X X X X X X X X X X X X ECG X X
evaluation Safety X X X laboratory evaluations Alcohol/ X X drug
screen FSH test X Pregnancy X X X test Randomization X Dose X X X X
X X X administration 24-hr X X X X X X X X X X X X X urine/stool
collection Stool X X X X X X X X X X X X X form/timing Pharmaco- X
X X X X dynamic laboratory evaluations AE X X X X X X X X X X
assessment
[0558] Study drug. Cpd 002 capsules or corresponding placebo
capsules were administered with approximately 240 mL of
non-carbonated water at multiples of 15 mg or placebo. Cpd 002 is
an amorphous, off-white powder and was supplied as a white, size 0,
hydroxypropylmethylcellulose (HPMC) capsule. Each capsule contained
15 mg of Cpd 002. Capsules were packaged in an opaque white high
density polyethylene (HDPE) bottle (10/bottle). The drug product
was formulated with no excipients.
[0559] Placebo was supplied as a white, size 0, HPMC capsule filled
with methylcellulose. Capsules were packaged in an opaque white
HDPE bottle (10/bottle).
[0560] Method of Assigning Subjects to Treatment Groups. The
clinical research organization statistician prepared the
randomization scheme in accordance with its standard operating
procedures (SOPs) and the randomization plan, which reflected GCP
standards.
[0561] After obtaining informed consent, subjects were allocated
sequentially to cohorts in their order of completing screening
assessments.
[0562] Within each cohort, a computer generated randomization
schedule was used to randomly assign subjects to active Cpd 002 or
placebo in a 4:1 ratio.
[0563] Once a subject was deemed eligible for randomization, the
next available randomization number was assigned sequentially and
the subject received the treatment indicated on the randomization
schedule. Subjects who withdrew early could be replaced, pending
discussion with the Sponsor. Replacement subjects received the same
blinded treatment as the original subject.
[0564] Selection and Timing of Dose for Each Subject. Subjects were
allocated sequentially to cohorts consisting of 15 subjects each in
their order of completing screening assessments and received either
002 or placebo based on random assignment. Table E10 provides the
actual dosing regimen for each cohort. Because this was an adaptive
design protocol, the dosing regimen of each cohort was based on
blinded results from previous cohorts.
TABLE-US-00013 TABLE E10 Dosing Regimen for Each Cohort Cohort No.
Subjects.sup.a Dose/Administration Regimen Total Dose/Day 1 15 30
mg bid 60 mg 3 15 60 mg bid 120 mg 4 15 15 mg bid 30 mg .sup.aEach
cohort consisted of 12 subjects administered CPD002 and 3 subjects
administered placebo.
[0565] Dosing was administered immediately prior to breakfast and
dinner. Subjects were not permitted to eat or drink anything from 8
hours before dosing at breakfast, with the exception of water up to
2 hours prior. Subjects were fed a standardized meal approximately
10 minutes after dosing.
[0566] The standardized diet included a Na+ content of
approximately 1500 mg for each meal. Dietary phosphorus was not
measured nor was it set to a predetermined value. It was expected
to range within the typical value, i.e. 750 mg-1250 mg per day.
[0567] Subjects did not have salt available to add to meals. Fluid
intake was ad libitum (and recorded) except as specified before
drug administration. Subjects were to refrain from strenuous
physical activity (e.g., contact sports) during study
participation.
[0568] Blinding. The treatment was administered in a double-blind
fashion. Only the site pharmacist responsible for dispensing the
product and the bioanalytical laboratory technician responsible for
performing the bioanalysis of plasma Cpd 002 had knowledge of the
treatments assigned.
[0569] The study was not unblinded for the safety reviews between
cohorts.
[0570] A third party maintained the randomization schedule in a
secure location with adequate controls to prevent unauthorized
access.
[0571] One set of unblinding envelopes (sealed envelopes containing
individual subject treatment assignment) was stored at the CPU.
[0572] The study was only unblinded once all data from the final
cohort was collected and the database was locked.
[0573] Prior and Concomitant Therapy. This was a study in healthy
subjects. Subjects with prior therapy specified in the exclusion
criteria were not eligible for entry into the study.
[0574] With the exception of HRT for postmenopausal women and
hormonal contraceptives, the use of concomitant medications was
prohibited during the study unless needed to treat an AE.
[0575] All previous medication (prescription and over-the-counter),
vitamin and mineral supplements, and herbs taken by the participant
in the past 30 days were recorded in the CRF, including start and
stop date, dose and route of administration, frequency and
indication. Medications taken for a procedure were also
included.
[0576] Treatment Compliance. All doses of study drug were given
under the supervision of clinic staff, with time and dose
administered recorded in the CRF. Clinical staff examined the
subject's oral cavity and hands after drug administration to ensure
that the capsule(s) was/were swallowed.
[0577] Efficacy Variables. The study consisted of a 3-week
screening period followed by a 5-day baseline assessment, a 7-day
double-blind treatment period with 2 days of follow-up for safety
and PD assessments. Fourteen days after the treatment period
subjects were contacted by telephone for a safety follow-up.
[0578] Subjects were admitted to the CPU 5 days prior to
administration of the first dosing of study drug and were confined
to the unit for the duration of the treatment period, being
released on Day 9.
[0579] Safety assessments were performed starting with Day -5 and
included physical examination; vital signs; 12-lead ECGs; routine
serum chemistry, hematology, and urinalysis; and AE reporting.
Pharmacodynamic assessments were performed daily from Day -4
through Day 9 and included urine and stool Na+ excretion, time to
first bowel movement, and stool parameters (consistency, weight,
and frequency). Pharmacodynamic laboratory assessments (plasma
renin, aldosterone, and NT-pro BNP) were collected on Days -4, -1,
3, 6, and 9.
[0580] Laboratory Assessments. Blood and urine samples for clinical
laboratory tests (hematology, chemistry, urinalysis) were collected
during screening (to meet inclusion/exclusion criteria) and at Day
-4, and Day 9 after waking and prior to breakfast.
[0581] In addition, blood was collected at screening and Day -5 for
alcohol/drug screening, FSH test (postmenopausal females only), and
pregnancy testing (all females). Virology screening for HBsAg, HCV,
and HIV were performed at screening.
[0582] Pharmacodynamic Variables. The following PD parameters were
monitored as a signal of potential drug activity: [0583] Stool Na+
excretion [0584] Stool Phosphorus excretion
[0585] Bowel movements. Study participants were instructed to
notify study personnel immediately before they had a bowel
movement. Study personnel recorded the time of every bowel movement
and assessed the stool parameters (e.g., consistency, weight).
Bowel movements that occurred prior to leaving the bathroom were
considered 1 bowel movement. All bowel movements were collected,
weighed, and stored by the CPU for total Na+ and P analysis;
collections were in 24-hour intervals.
[0586] Pharmacodynamic Analyses--Stool Sodium and Phosphorus
Analytical methods. The human fecal samples were processed with
nitric acid to give pre-digested sample ("Pre-digests") prior to
laboratory determination of sodium and phosphorus contents.
Pre-digest were digested further in nitric acid at 100.degree. C.
followed by hydrochloric acid at 100.degree. C. and diluted with
deionized water. Yttrium was added to the digestion as internal
standard. Calibration standards and quality control samples were
digested with the same procedure. Sodium and phosphorus
concentrations were determined by an inductively coupled plasma
optical emission spectrometric (ICP-OES) method. The light
intensity of analyte and yttrium were measured at the SCD (array)
detectors. The analyte-to-yttrium intensity ratios were converted
to solution concentrations via the instrument software. Total
sodium and phosphorus content in each sample was calculated using
the sample volumes obtained during the pre-digestion process and
the concentrations measured.
[0587] Results. Upon unblinding of the data, pharmacodynamic
measurement of fecal and urine P and Na were assigned to the
placebo group (3 subjects embedded in each cohort.times.3 cohorts=9
subjects) and to the 3 treated groups respectively. The data are
shown in FIGS. 14A-B. FIG. 14A shows the mean average daily fecal
excretion of Na (+/-SE), averaged over the 7-day treatment period
(Day 1 to Day 7) and reported as mEq/day. FIG. 14B shows the mean
average daily fecal excretion of phosphorus (+/-), averaged over
the 7-day treatment period (Day 1 to Day 7) and reported as
mEq/day. Statistical analysis was performed by one-way ANOVA; (*);
p<0.05, (**); p<0.01, (***); p<0.001.
Example 9
Evaluation of Activity in the Reduction of Dietary Phosphorus at
Dose 15 mg BID in a 7-Day Repeat Dose Crossover Study in Healthy
Volunteers
[0588] A Phase 1, single-center, randomized, 3-way cross-over, open
label study was designed to evaluate the pharmacodynamics of Cpd
002 for three different formulations of Cpd 002 administered twice
daily PO for 4 days in healthy male and female subjects taking a
proton pump inhibitor (omeprazole), utilizing a three-way crossover
design. Many potential patients take either PPIs or H2 antagonists
for the treatment of gastroesophageal reflux disease (GERD).
However, the in vitro dissolution profiles of Cpd 002 formulations
can be affected by a high pH, where slower and/or incomplete
dissolution is sometimes observed. In order to evaluate the
pharmacodynamic activity of the drug in the context of elevated
gastric pH, subjects in this study were required to be on
omeprazole starting on Day -5 throughout the treatment period.
[0589] Subjects were screened within 3 weeks of enrollment. Each
subject took Omeprazole 20 mg twice daily beginning on Day -5.
Subjects checked in a Clinical Pharmacology Unit (CPU) on Day -2
before dinner. Each subject received a diet standardized for Na+
content while in the CPU. Subjects received one of three
formulations of Cpd 002 BID with approximately 240 mL of
non-carbonated water on Days 1 to 4, 7 to 10, and 13 to 16 (a
different formulation each time). Subjects were fed breakfast
and/or dinner within approximately 5 minutes after dosing. There
was a two day wash out period between each treatment period.
[0590] While confined to the CPU, Na+-standardized meals were
provided per CPU procedures. Pharmacodynamic assessment included
24-hour urinary sodium and phosphorus and fecal sodium and
phosphorus measurements.
[0591] At least 18 healthy male and female subjects were randomized
in this study.
[0592] Subject Selection Criteria--Inclusion criteria.
[0593] 1. Healthy man or woman aged 19 to 65 years, inclusive.
[0594] 2. Body mass index between 18 and 29.9 kg/m2, inclusive.
[0595] 3. No clinically significant abnormalities in the medical
history, physical examinations, or clinical laboratory evaluations
at screening.
[0596] 4. Able to understand and comply with the protocol.
[0597] 5. Willing and able to sign informed consent; signed and
dated, written informed consent prior to any study specific
procedures.
[0598] 6. Females of child-bearing potential must have a negative
pregnancy test at screening and on admission to the unit and must
not be lactating.
[0599] 7. Females of childbearing potential included in the study
must use two effective methods of avoiding pregnancy (including
oral, transdermal or implanted contraceptives, intrauterine device,
female condom with spermicide, diaphragm with spermicide, cervical
cap, or use of a condom with spermicide by sexual partner from
screening to the follow-up visit.
[0600] 8. Females of non-child bearing potential, confirmed at
screening, must fulfill one of the following criteria: [0601] a.
Post-menopausal defined as amenorrhea for at least 12 months or
more; following cessation of all exogenous hormonal treatments and
LH and FSH levels in the post-menopausal range; or [0602] b.
Documentation of irreversible surgical sterilization by
hysterectomy, bilateral oophorectomy or bilateral salpingectomy but
not tubal ligation.
[0603] 9. Males must be either be sterile, abstinent or agree to
use, from check-in until 45 days from final study visit, one of the
following approved methods of contraception: a male condom with
spermicide; a sterile sexual partner; use by female sexual partner
of an IUD with spermicide, a female condom with spermicide,
contraceptive sponge with spermicide, an intravaginal system (eg,
NuvaRing), a diaphragm with spermicide, a cervical cap with
spermicide, or oral, implantable, transdermal, or injectable
contraceptives.
[0604] 10. For inclusion in the optional genetic research, patients
must fulfill all of the inclusion criteria described above and
provide informed consent for the genetic sampling and analyses.
[0605] Exclusion Criteria. Subjects were excluded from the study if
they met any of the following criteria:
[0606] 1. Diagnosis or treatment of any clinically symptomatic
biochemical or structural abnormality of the gastrointestinal (GI)
tract.
[0607] 2. Any surgery on the small intestine or colon, excluding
appendectomy or cholecystectomy or any other condition known to
interfere with absorption, distribution, metabolism or excretion of
drugs.
[0608] 3. Clinical evidence of significant cardiovascular,
respiratory, renal, hepatic, gastrointestinal, hematologic,
metabolic, endocrine, neurologic, psychiatric disease, or any
condition that may interfere with the subject successfully
completing the trial or that would present a safety risk to the
subject.
[0609] 4. History of severe allergy/hypersensitivity or ongoing
allergy/hypersensitivity, as judged by the investigator or history
of hypersensitivity to drugs with a similar chemical structure or
class to CPD002.
[0610] 5. Loose stools (Bristol Stool Form Score of 6 or
7).gtoreq.2 days in the past 7 days.
[0611] 6. Hepatic dysfunction (alanine aminotransaminase [ALT] or
aspartate aminotransaminase [AST])>1.5 times the upper limit of
normal [ULN]) or renal impairment (serum creatinine>ULN).
[0612] 7. Clinically significant laboratory results at screening as
determined by the investigator.
[0613] 8. Any evidence of or treatment of malignancy, excluding
non-melanomatous malignancies of the skin.
[0614] 9. If, in the opinion of the investigator the subject is
unable or unwilling to fulfill the requirements of the protocol or
has a condition, which would render the results
uninterpretable.
[0615] 10. Use of diuretic medications; medications that are known
to affect stool consistency and/or GI motility, including fiber
supplements (unless required by study), anti-diarrheals,
cathartics, antacids, opiates, narcotics, prokinetic drugs, enemas,
antibiotics, probiotic medications or supplements; or salt or
electrolyte supplements containing sodium, potassium, chloride, or
bicarbonate formulations from CPU check in (Day -2) to CPU check
out (Day 17).
[0616] 11. Use of an investigational agent within 30 days prior to
Day -2.
[0617] 12. Positive virology (active hepatitis B infection,
hepatitis C infection, or human immunodeficiency virus), alcohol,
or drugs of abuse test during screening.
[0618] 13. Use of any prescription medication within 7 days before
admission to the CPU, or required chronic use of any prescription
or non-prescription medication, with the exception of hormonal
replacement therapy for postmenopausal women and hormonal
contraceptives.
[0619] 14. History of tobacco use, alcohol abuse, illicit drug use,
significant mental illness, physical dependence to any opioid, or
any history of drug abuse or addiction within 12 months of study
enrollment.
[0620] 15. Have had significant blood loss (>450 mL) or have
donated 1 or more units of blood or plasma within 8 weeks prior to
study entry.
[0621] Study drug. Cpd 002 bis-HCl (e.g., the dihydrochloride salt
of Cpd 002) capsules, Cpd 002 bis-HCl tablets and Cpd 002 free base
tablets. The Cpd 002 bis-HCl salt is an amorphous, off-white
powder. The Cpd 002 free base is a white, crystalline solid. Cpd
002 is presented as either a white size 0 HPMC
(hydroxypropylmethylcellulose) capsule or a round, white tablet.
The capsules were manufactured at a dosage strength of 15 mg on the
basis of the Cpd 002 dihydrochloride formula weight, which is
equivalent to 14 mg of the Cpd 002 free base. To ensure comparable
dosage strengths across this study, tablets of both the
dihydrochloride salt and free base were manufactured at a dosage
strength reflecting 14 mg on the basis of the free base. Capsules
and tablets were packaged in a white HDPE (high-density
polyethylene) bottle. Capsules and tablets of Cpd 002 were stored
refrigerated (2 to 8.degree. C.) in the original packaging until
use. The components of the tablets are described in Table E1
below.
TABLE-US-00014 TABLE E11 Free Base Dihydrochloride Salt Wt/Tablet
Wt/Tablet Component % Form (mg) % Form (mg) Cpd 002 5.9 14.7.sup.a
6.4 15.9.sup.a Prosolv HD90 86.1 215.3 85.6 214.1 Polyplasdone XL
5.00 12.5 5.00 12.5 Mg Stearate 2.00 5.0 2.00 5.0 Cabosil 1.00 2.5
1.00 2.5 Totals 100.00 250.0 100.00 250.0 .sup.aCorrected for
purity, residual solvents, water content, and inorganic
content.
[0622] Dose and Route of Administration. Cpd 002 capsules or
tablets, 15 mg (14 mg free base equivalents) were administered with
approximately 240 mL of non-carbonated water twice daily PO prior
to breakfast and dinner for 4 consecutive days per treatment
period, with 2 day wash out periods between treatments. Omeprazole
20 mg BID was administered to screened subjects beginning on day
-5. All subjects took omeprazole 20 mg twice daily one hour before
intake of Cpd 002 each day until their last dose of study drug on
Day 16. See Table E12 below.
TABLE-US-00015 TABLE E12 Treatments Subjects.sup.a
Dose/Administration.sup.b Regimen Formulation 1 18 15 mg BID Cpd
002 bis-HCl capsule 2 18 15 mg BID Cpd 002 bis-HCl capsule 3 18 15
mg BID Cpd 002 tablet .sup.aAll subjects received all three
treatments; 6 subjects/treatment period. There was a 2 day wash out
between each treatment period. .sup.bDoses are in equivalents of
CPD002 free base (MW 1145.049).
[0623] Once a subject was deemed eligible for randomization, the
next available randomization number was assigned sequentially and
the subject received the sequence of treatment indicated on the
randomization schedule. All doses of study drug were given under
the supervision of clinic staff, with time, and dose administered
recorded in the case report form (CRF). Clinical staff examined the
subject's oral cavity and hands after drug administration to ensure
that capsule was swallowed.
[0624] Fluid and Food Intake. Subjects participating in the study
were given a standardized diet with an approximate sodium content
(approximately 1500 mg for each meal). Dietary phosphorus was not
measured nor was it set to a predetermined value. It was expected
to range within the typical value, i.e. 750 mg-1250 mg per day.
Subjects did not have salt or any other sodium containing spices or
sauces available to add to meals.
[0625] Fluid intake were ad libitum except as specified before drug
administration. Daily menus (food and fluid) were similar during
each treatment period.
[0626] Pharmacodynamic variables. The following parameters were
monitored as signal of potential drug activity. [0627] Urine sodium
excretion (daily) [0628] Fecal sodium excretion (daily)
[0629] Bowel movement and urine collection were performed as
described earlier (Example 8); the pharmacodynamics activity of the
three dosage forms was assessed as follows. A baseline fecal
excretion of phosphorus or sodium was established as the average
daily fecal excretion of phosphorus or sodium during Day-1 to Day
0, with the exception of one subject for whom the baseline was
established during the first washout period, i.e., from Day 6 and
Day 7. The daily fecal excretion of phosphorus or sodium upon
treatment was measured by averaging fecal phosphorus or sodium
excretion over the 4-day treatment period. The same method was used
for urine.
[0630] Results. The results are shown in FIGS. 15A-C. Statistical
analysis was performed by one-way ANOVA; (*); p<0.05, (**);
p<0.01, (***); p<0.001.
[0631] FIG. 15A shows the mean average daily excretion of
phosphorus (+/-SE). A baseline fecal excretion of phosphorus or
sodium was established as the average daily fecal excretion of
phosphorus or sodium during Day-1 to Day 0, with the exception of
one subject for whom the baseline was established during the first
washout period, i.e. from Day 6 and Day 7 (referred to as
"Predose"). The daily fecal excretion of phosphorus upon treatment
with 15 mg BID HCl tablets was measured by averaging fecal
phosphorus or sodium excretion over the 4-day treatment period.
[0632] FIG. 15B shows the average daily urinary excretion of sodium
(+/-SE). A baseline fecal excretion of sodium was established as
the average daily urinary excretion of sodium during Day-1 to Day
0, with the exception of one subject for whom the baseline was
established during the first washout period, i.e. from Day 6 and
Day 7 (referred to as "Predose"). The daily urinary excretion of
sodium upon treatment with the three forms of drug products was
measured by averaging urinary sodium excretion over the 4-day
treatment period.
[0633] FIG. 15C shows the average daily urinary excretion of
phosphorus (+/-). A baseline fecal excretion of phosphorus was
established as the average daily urinary excretion of phosphorus
during Day-1 to Day 0, with the exception of one subject for whom
the baseline was established during the first washout period, i.e.
from Day 6 and Day 7 (referred to as "Predose"). The daily urinary
excretion of phosphorus upon treatment with the three forms of drug
products was measured by averaging urinary sodium excretion over
the 4-day treatment period.
Example 10
The Effect of Renvela.RTM. on the Pharmacodynamics of CP002
[0634] A Phase 1, single-center, randomized, open label study was
designed to evaluate the effect of Renvela.RTM. on the
pharmacodynamic activity of CP002, as the dihydrochloride salt (see
Table E4) administered twice daily PO for 4 days in healthy male
and female subjects.
[0635] Subjects were screened within 3 weeks of enrollment.
Eighteen subjects checked in to the CPU on Day -2 before dinner.
Each subject received a diet standardized for Na+ content while in
the CPU. Subjects received 15 mg CP002 BID on Days 1 to 4, and Days
7 to 10. Subjects were fed breakfast and/or dinner within
approximately 5 minutes after dosing. During one of the two
treatment periods (randomly assigned), subjects received one
Renvela.RTM. 800 mg tablet with breakfast, lunch and dinner (either
Days 1 to 4 or Days 7 to 10). There was a two day wash out period
between each treatment period. While confined to the CPU,
Na+-standardized meals were provided per CPU procedures.
Pharmacodynamic assessment included 24-hour fecal sodium and
phosphorus measurements.
[0636] The subject selection criteria and description of the study
drug were the same as described for Example 9 (supra). The schedule
of assessments and procedures is shown in Table E13 below.
TABLE-US-00016 TABLE E13 Study Procedure Screening Run-in Treatment
Period 1 Washout/Run-in Treatment Period 2 Day -21 to -3 -2 -1 1 2
3 4 5 6 7 8 9 10 Renvela .RTM. X X X X X X X X administration CP002
X X X X X X X X administration 24 hour urine/ X X X X X X X X X X X
stool collection Stool X X X X X X X X X X X X assessment PK blood
X X sampling
[0637] Pharmacodynamic variables. A baseline fecal excretion of
phosphorus or sodium was established as the average daily fecal
excretion of phosphorus or sodium during Day-1 to Day 0. The daily
fecal excretion of phosphorus or sodium upon treatment was measured
by averaging fecal phosphorus or sodium excretion over the 4-day
treatment period. Sodium and phosphorus analytical methods were
performed as described in Example 8 (supra).
[0638] Results. The data are shown in FIGS. 16A-B. Statistical
analysis performed by one-way ANOVA followed by Tukey's multiple
comparison's test; (*); p<0.05, (**); p<0.01, (***);
p<0.001. vs. pre-Dose.
[0639] The mean average daily fecal excretion of sodium (+/-SE) is
shown in FIG. 16A. Here, a baseline fecal excretion of sodium was
established as the average daily fecal excretion of phosphorus or
sodium during Day-1 to Day 0, (referred to as "Predose"). The daily
fecal excretion of sodium upon treatment with 15 mg BID bis-HCl
tablets was measured by averaging fecal sodium excretion over the
4-day treatment period.
[0640] The mean average daily fecal excretion of phoshorus (+/-SE)
is shown in FIG. 16B. A baseline fecal excretion of phosphorus was
established as the average daily fecal excretion of phosphorus
during Day-1 to Day 0, (referred to as "Predose"). The daily fecal
excretion of phosphorus upon treatment with 15 mg BID bis-HCl
tablets was measured by averaging fecal phosphorus excretion over
the 4-day treatment period.
* * * * *