U.S. patent application number 11/105081 was filed with the patent office on 2005-10-27 for method, compositions and kits for increasing the oral bioavailability of pharmaceutical agents.
This patent application is currently assigned to Baker Norton Pharmaceuticals, Inc.. Invention is credited to Broder, Samuel, Duchin, Kenneth L., Selim, Sami.
Application Number | 20050238634 11/105081 |
Document ID | / |
Family ID | 27358262 |
Filed Date | 2005-10-27 |
United States Patent
Application |
20050238634 |
Kind Code |
A1 |
Broder, Samuel ; et
al. |
October 27, 2005 |
Method, compositions and kits for increasing the oral
bioavailability of pharmaceutical agents
Abstract
A method of increasing the bioavailability upon oral
administration of a pharmacologically active target agent,
particularly an antitumor or antineoplastic agent which exhibits
poor or inconsistent oral bioavailability (e.g., paclitaxel,
docetaxel or etoposide), comprises the oral co-administration to a
mammalian patient of the target agent and an oral
bioavailability-enhancing agent (e.g., cyclosporin A, cyclosporin
D, cyclosporin F or ketoconazole). The enhancing agent may be
administered orally from 0.5-24 hrs. prior to the oral
administration of one or more doses of the target agent,
substantially simultaneously with the target agent or both prior to
and substantially simultaneously with the target agent. A method of
treating mammalian patients suffering from diseases responsive to
target agents with poor oral bioavailability, as well as oral
dosage forms containing such target agents, combination oral dosage
forms containing bioavailability-enhancing agents and target agents
and kits containing enhancing and target agent dosage forms and
dosing information for the co-administration of the same are also
disclosed.
Inventors: |
Broder, Samuel; (Weston,
FL) ; Duchin, Kenneth L.; (Fort Lauderdale, FL)
; Selim, Sami; (Irvine, CA) |
Correspondence
Address: |
LERNER, DAVID, LITTENBERG,
KRUMHOLZ & MENTLIK
600 SOUTH AVENUE WEST
WESTFIELD
NJ
07090
US
|
Assignee: |
Baker Norton Pharmaceuticals,
Inc.
Miami
FL
|
Family ID: |
27358262 |
Appl. No.: |
11/105081 |
Filed: |
April 13, 2005 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
11105081 |
Apr 13, 2005 |
|
|
|
10800990 |
Mar 15, 2004 |
|
|
|
10800990 |
Mar 15, 2004 |
|
|
|
10242050 |
Sep 12, 2002 |
|
|
|
6818615 |
|
|
|
|
10242050 |
Sep 12, 2002 |
|
|
|
09829846 |
Apr 10, 2001 |
|
|
|
6610735 |
|
|
|
|
09829846 |
Apr 10, 2001 |
|
|
|
08733142 |
Oct 16, 1996 |
|
|
|
6245805 |
|
|
|
|
08733142 |
Oct 16, 1996 |
|
|
|
08608776 |
Feb 29, 1996 |
|
|
|
5968972 |
|
|
|
|
60007071 |
Oct 26, 1995 |
|
|
|
Current U.S.
Class: |
424/94.2 ;
514/449 |
Current CPC
Class: |
Y02A 50/411 20180101;
A61K 45/06 20130101; A61K 31/337 20130101; A61P 13/12 20180101;
A61K 38/13 20130101; A61P 31/12 20180101; Y02A 50/30 20180101; A61K
31/00 20130101; A61P 35/00 20180101; A61K 31/00 20130101; A61K
2300/00 20130101; A61K 38/13 20130101; A61K 2300/00 20130101; A61K
31/337 20130101; A61K 2300/00 20130101 |
Class at
Publication: |
424/094.2 ;
514/449 |
International
Class: |
A61K 038/54; A61K
031/337 |
Claims
We claim:
1. A method of increasing the bioavailability upon oral
administration to a human patient of a taxane, comprising orally
co-administering to the human patient a taxane and an oral
bioavailability-enhancing agent comprising a P-glycoprotein
inhibitor, wherein the oral bioavailability enhancing agent is
administered substantially simultaneously with administration of
the taxane, prior to administration of the taxane, or both prior to
and substantially simultaneously with administration of the taxane.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent
application Ser. No. 10/800,990 filed Mar. 15, 2004, which is a
continuation of U.S. patent application Ser. No. 10/242,050 filed
Sep. 12, 2002, which is a continuation of U.S. patent application
Ser. No. 09/829,846, filed Apr. 10, 2001, now U.S. Pat. No.
6,610,735, which application is a divisional of application Ser.
No. 08/733,142, filed Oct. 16, 1996, now U.S. Pat. No. 6,245,805,
which is a continuation-in-part of co-pending application Ser. No.
08/608,776, filed Feb. 29, 1996, now U.S. Pat. No. 5,968,972, which
claims the priority of provisional application Ser. No. 60/007,071,
filed Oct. 26, 1995, the disclosures of which are incorporated by
reference herein.
REFERENCE TO DISCLOSURE DOCUMENTS
[0002] This application incorporates material included in
Disclosure Document No. 377063, filed Jun. 23, 1995, No. 386504,
filed Dec. 11, 1995, No. 391109, filed Feb. 7, 1996, and No.
391228, filed Feb. 7, 1996.
BACKGROUND OF THE INVENTION
[0003] The invention relates to methods, compositions and kits for
improving the oral bioavailability of pharmaceutical agents that
are poorly absorbed from the gastrointestinal tract, and to methods
of treatment of patients through the oral administration of such
agents. One aspect of the invention relates to the use of
cyclosporins to enhance the oral bioavailability of paclitaxel and
related taxanes.
DESCRIPTION OF THE PRIOR ART
[0004] Many valuable pharmacologically active compounds cannot be
effectively administered by the oral route because of poor systemic
absorption from the gastrointestinal tract. All these
pharmaceutical agents are, therefore, generally administered via
intravenous or intramuscular routes, requiring intervention by a
physician or other health care professional, entailing considerable
discomfort and potential local trauma to the patient and even
requiring administration in a hospital setting with surgical access
in the case of certain IV infusions.
[0005] It has been speculated that, in some cases, the poor
bioavailability of a drug after oral administration is a result of
the activity of a multidrug transporter, a membrane-bound
P-glycoprotein, which functions as an energy-dependent transport or
efflux pump to decrease intracellular accumulation of drug by
extruding xenobiotics from the cell. This P-glycoprotein has been
identified in normal tissues of secretory endothelium, such as the
biliary lining, brush border of the proximal tubule in the kidney
and luminal surface of the intestine, and vascular endothelial
cells lining the blood brain barrier, placenta and testis.
[0006] It is believed that the P-glycoprotein efflux pump prevents
certain pharmaceutical compounds from transversing the mucosal
cells of the small intestine and, therefore, from being absorbed
into the systemic circulation. A number of known non-cytotoxic
pharmacological agents have been shown to inhibit P-glycoprotein,
including cyclosporin A (also known as cyclosporin), verapamil,
tamoxifen, quinidine and phenothiazines, among others. Many of
these studies were aimed at achieving greater accumulation of
cytotoxic drugs inside tumor cells. In fact, clinical trials have
been conducted to study the effects of cyclosporin on the
pharmacokinetics and toxicities of paclitaxel (Fisher et al., Proc.
Am. Soc. Clin. Oncol. 13: 143 1994); doxorubicin (Bartlett et al.,
J. Clin. Onc. 12:835-842, 1994); and etoposide (Lum et al., J.
Clin. Onc. 10:1635-42, 1992), all of which are anti-cancer agents
known to be subject to multidrug resistance (MDR). These trials
showed that patients receiving intravenous cyclosporin prior to or
together with the anti-cancer drugs had higher blood levels of
those drugs, presumably through reduced body clearance, and
exhibited the expected toxicity at substantially lower dosage
levels. These findings tended to indicate that the concomitant
administration of cyclosporin suppressed the MDR action of
P-glycoprotein, enabling larger intracellular accumulations of the
therapeutic agents. For a general discussion of the pharmacologic
implications for the clinical use of P-glycoprotein inhibitors, see
Lum et al., Drug Resist. Clin. Onc. Hemat. 9: 319-336 (1995);
Schinkel et al., Eur. J. Cancer 31A: 1295-1298 (1995).
[0007] In the aforedescribed studies relating to the use of
cyclosporin to increase the blood levels of pharmaceutical agents
subject to P-glycoprotein mediated resistance, the active agents
and the cyclosporin were administered intravenously. No suggestion
was made in these publications that cyclosporin or other substances
believed to inhibit the P-glycoprotein efflux pump could be orally
administered to substantially increase the bioavailability of
orally administered anti-cancer drugs and other pharmaceutical
agents which are themselves poorly absorbed from the gut without
producing highly toxic side effects. Indeed, in the 1995 review
paper cited above, Lum et al. showed that concomitant IV
administration of MDR inhibitors and chemotherapeutic agents
subject to MDR increased toxicity levels and exacerbated the
patients' serious side effects. Schinkel et al. briefly adverted to
the fact that MDR1 and P-glycoprotein are abundant in the mucosal
cells of the intestine, and that this may affect the oral
bioavailability of P-glycoprotein substrate drugs, but did not
suggest or imply that the oral administration of MDR suppressing
agents could improve the bioavailability of the orally unavailable
agents. Furthermore, like Lum et al., Schinkel et al. warned that
P-glycoprotein inhibitors can dramatically increase toxicity in
chemotherapy patients and should, therefore, be used
cautiously.
[0008] In an earlier publication, Schinkel et al. showed that
absorption of orally ingested ivermectin was increased in mice
homozygous for a disruption of the MDR1 a gene in comparison with
normal mice, demonstrating that P-glycoprotein played a major role
in reducing the bioavailability of this agent (Cell, 77: 491-502,
1994). In addition, this study also showed that the penetration of
vinblastine into various tissues was enhanced in the mutant
mice.
[0009] None of the published studies provided any regimen for
implementing the effective oral administration of otherwise poorly
bioavailable drugs, e.g., indicating the respective dosage ranges
and timing of administration for specific target drugs and
bioavailability-enhancing agents or demonstrating which
MDR-inhibiting agents are best suited for promoting oral absorption
of each target drug or class of drugs.
[0010] Methods disclosed in the art for increasing gut absorption
of drugs that have until now only been administered parenterally
generally focus on the use of permeation and solubility enhancers
as promoting agents, or the co-administration by intraluminal
perfusion in the small intestine or by the intravenous route of
P-glycoprotein inhibitors, e.g., Leu et al., Cancer Chemother.
Pharmacol. 35: 432-436, 1995 (perfusion or IV infusion of quinidine
suppresses efflux of etoposide into the lumen of the G.I. tract
from the blood). But these methods suffer from numerous drawbacks.
The solubility and permeability enhancing agents are often either
impractical or ineffective for oral administration in the doses
required and may interfere with the pharmacological activity of the
target drug. Parenteral administration of P-glycoprotein inhibitors
in therapeutic (or near-therapeutic) doses into humans can cause
severe clinical consequences. In the case of quinidine, for
example, IV administration may cause arrhythmias, peripheral
vasodilation, gastrointestinal upset and the like.
[0011] In published PCT application WO 95/20980 (published Aug. 10,
1995) Benet et al. disclose a purported method for increasing the
bioavailability of orally administered hydrophobic pharmaceutical
compounds. This method comprises orally administering such
compounds to the patient concurrently with a bioenhancer comprising
an inhibitor of a cytochrome P450 3A enzyme or an inhibitor of
P-glycoprotein-mediated membrane transport.
[0012] Benet et al., however, provide virtually no means for
identifying which bioavailability enhancing agents will improve the
availability of specific "target" pharmaceutical compounds, nor do
they indicate specific dosage amounts, schedules or regimens for
administration of the enhancing or target agents. In fact, although
the Benet application lists dozens of potential enhancers (P450 3A
inhibitors) and target drugs (P450 3A substrates), the only
combination of enhancer and target agent supported by any
experimental evidence in the application is ketoconazole as the
enhancer and cyclosporin A as the target drug.
[0013] When describing the general characteristics of compounds
which can be used as bioenhancers by reduction of P-glycoprotein
transport activity, Benet et al. indicate that these are
hydrophobic compounds which generally, but not necessarily,
comprise two co-planar aromatic rings, a positively charged
nitrogen group or a carbonyl group--a class that includes an
enormous number of compounds, most of which would not provide the
desired absorption enhancing activity in the case of specific
target agents. Moreover, the classes of target agents disclosed by
Benet et al. include the great majority of pharmaceutical agents
listed in the Physicians' Desk Reference. These inclusion criteria
are of no value to medical practitioners seeking safe, practical
and effective methods of orally administering specific
pharmaceutical agents.
[0014] A further deficiency with Benet et al.'s disclosure is the
standard applied for determinating as to whether bioavailability of
a drug that is poorly absorbed upon oral administration has been
improved. Benet et al. indicate that any P-glycoprotein inhibiting
agent which, when present in the gut at a given concentration,
reduces transmembranal transport of Rhodamine 123 by P-glycoprotein
in brush border membrane vesicles or P-glycoprotein containing
cells by 10% or more may be considered a bioenhancing agent at that
concentration and can be used in the practice of their invention.
But an increase of only 10% in absorption from the gut of an
otherwise not absorbable agent is inadequate to render the agent
therapeutically valuable for any purpose. Indeed, under guidelines
of the Federal Food and Drug Administration, two pharmaceutical
formulations containing the same active ingredient, but differing
in their bioavailability levels by -20%/+25%, are still considered
bioequivalent because for most drugs a -20%/+25% difference in
concentration of the active ingredient in the blood is not
clinically significant. Approved Drug Products with Therapeutic
Equivalence Evaluations (Dept. of HHS, 14th ed. 1994). When the FDA
rules that two pharmaceutical formulations are bioequivalent,
physicians and pharmacists consider them freely substitutable for
one another.
[0015] In general, Benet et al. provides no teaching that could be
followed by persons skilled in the medical and pharmaceutical arts
to identify suitable bioenhancer/target drug combinations or to
design specific treatment regimens and schedules which would render
the target agents therapeutically effective upon oral
administration.
[0016] Thus, a safe yet effective method for increasing the
systemic availability upon oral administration of drugs that are
currently administered only parenterally because they are not
absorbed sufficiently or consistently when administered by the oral
route is required and has not been provided in the prior art.
SUMMARY OF THE INVENTION
[0017] Surprisingly, it has now been discovered and experimentally
verified that certain agents which apparently inhibit
P-glycoprotein drug transport activity, particularly cyclosporins,
can be used to increase substantially the oral bioavailability of
otherwise poorly available or non-available pharmaceutical agents,
e.g., the anti-cancer drugs paclitaxel (formerly known as taxol),
as well as its analogs and derivatives, and etoposide.
[0018] The present invention relates in one aspect to a method of
increasing the oral bioavailability of pharmaceutical agents that
are poorly absorbed or not absorbed at all from the
gastrointestinal tract or gut by pre-administering and/or
simultaneously administering to a subject by the oral route one or
a combination of agents known to be effective in inhibiting the
P-glycoprotein drug transport pump. If pre-administration is used,
the bioavailability enhancing agent or agents must be administered
in sufficient quantities and within a short enough time period
before administration of the drug whose bioavailability is to be
increased (the "target drug" or "target agent") so that a
sufficient level of the enhancing agent remains at the site of
absorption at the time of administration of the target agent to
effectively inhibit the activity of the P-glycoprotein or other
multi-drug transporter substances.
[0019] In a second aspect, the invention pertains to compositions
or dosage forms for oral administration of pharmaceutical agents
that were heretofore available for parenteral administration only.
A third aspect of the invention relates to the administration of
such oral dosage forms or a combination thereof to patients for
treatment of diseases responsive to the active agents contained
therein.
[0020] The invention also pertains to pharmaceutical kits
comprising one or more oral dosage forms containing a target agent
and one or more oral dosage forms containing an enhancing
agent.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] FIG. 1 is a graph reflecting the levels of paclitaxel in
serum samples taken over a period of 6-8 hours from three groups of
rats: one group administered only paclitaxel by intravenous
administration, a second group administered only oral paclitaxel
and a third group administered oral paclitaxel with oral
cyclosporin A (hereinafter referred to as cyclosporin or CsA) doses
prior to and immediately after the paclitaxel dose.
[0022] FIG. 2 is a graph comparing the levels of paclitaxel in
serum taken from two of the three groups of rats reflected in FIG.
1: the group administered oral paclitaxel alone and the group
administered oral paclitaxel with prior and concomitant doses of
oral cyclosporin.
[0023] FIG. 3 is a graph reflecting the levels of paclitaxel in
plasma samples taken over a period of 24 hours from two groups of
rats: one group (A) administered cyclosporin orally one hour prior
to the combination of cyclosporin plus oral paclitaxel and the
second group (F) administered oral cyclosporin alone one hour prior
to oral paclitaxel.
[0024] FIG. 4 is a graph reflecting the levels of paclitaxel in
plasma samples from two groups of rats: one group (G) administered
paclitaxel IV 3 hours after an oral dose of cyclosporin and the
second group (H) administered only paclitaxel IV.
[0025] FIG. 5 is a graph reflecting the levels of radioactivity
detected in whole blood samples taken from three groups of rats
over a period of 24 hours: one (Group A) administered only
radiolabeled paclitaxel IV, a second (Group B) administered only
radiolabeled paclitaxel orally and a third group (Group C)
administered radiolabeled paclitaxel orally with oral cyclosporin
doses prior to and immediately after the paclitaxel dose.
[0026] FIG. 6 is a graph reflecting the levels of radioactivity
detected in whole blood samples taken from the individual rats in
Group B (defined with respect to FIG. 5).
[0027] FIG. 7 is a graph reflecting the levels of radioactivity
detected in whole blood samples taken from the individual rats in
Group C (defined with respect to FIG. 5).
[0028] FIG. 7A is a graph reflecting the levels of total
radioactivity and unchanged paclitaxel detected in whole blood
samples taken from a group of 10 rats over a period of 24 hours,
said group having been administered radiolabeled paclitaxel (9
mg/kg) orally with oral cyclosporin doses (5 mg/kg) prior to and
immediately after the paclitaxel dose.
[0029] FIG. 7B is a graph reflecting the levels of total
radioactivity and paclitaxel metabolites 1, 2 and 3 detected in
whole blood samples taken from the group of 10 rats defined with
respect to FIG. 7A over a period of 24 hours.
[0030] FIG. 8 is a graph reflecting the levels of radioactivity
detected in whole blood samples taken from three groups of rats
over a period of 24 hours: one group administered 10 mg/kg of
verapamil orally as an enhancing agent, a second administered
progesterone orally as an enhancing agent and a third administered
dipyridamole orally as an enhancing agent, with each group being
administered an oral dose of the same enhancing agent one hour
later immediately after an oral dose of radiolabeled
paclitaxel.
[0031] FIG. 9 is a graph reflecting the levels of radioactivity
detected in whole blood samples taken over a period of 24 hours
from the rats of the first group defined with respect to FIG. 8
(administered 10 mg/kg verapamil orally), a group of rats
administered oral radiolabeled paclitaxel alone and a group of rats
administered cyclosporin orally one hour prior to and again
immediately after radiolabeled oral paclitaxel.
[0032] FIG. 10 is a graph reflecting the levels of radioactivity
detected in whole blood samples taken over a period of 24 hours
from the rats of the second group defined with respect to FIG. 8
(administered progesterone orally), a group of rats administered
radiolabeled oral paclitaxel alone and a group of rats administered
cyclosporin orally one hour prior to and again immediately after
radiolabeled oral paclitaxel.
[0033] FIG. 11 is a graph reflecting the levels of radioactivity
detected in whole blood samples taken over a period of 24 hours
from the rats of the third group defined with respect to FIG. 8
(administered dipyridamole orally), a group of rats administered
radiolabeled oral paclitaxel alone and a group of rats receiving
cyclosporin orally one hour prior to and again immediately after
radiolabeled oral paclitaxel.
[0034] FIG. 12 is a graph reflecting the levels of radioactivity
detected in whole blood samples taken from three groups of rats
over a period of 24 hours: one group administered 100 mg/kg of
verapamil orally.sup.1 as an enhancing agent, a second administered
megestrol acetate (marketed as MEGACE by Bristol-Myers Squibb
Oncology) orally as an enhancing agent and a third administered
ketoconazole orally as an enhancing agent, with each group being
administered the same oral dose of the same enhancing agent one
hour later immediately after an oral dose of radiolabeled
paclitaxel. .sup.1As reflected on FIG. 12 the rats in the group
receiving high dose verapamil did not survive beyond about 8
hours.
[0035] FIG. 13 is a graph reflecting the levels of radioactivity
detected in whole blood samples taken over a period of 24 hours
from the rats of the first group defined with respect to FIG. 12
(administered 100 mg/kg verapamil orally), a group of rats
administered radiolabeled oral paclitaxel alone and a group of rats
administered cyclosporin orally one hour prior to and again
immediately after radiolabeled oral paclitaxel.
[0036] FIG. 14 is a graph reflecting the levels of radioactivity
detected in whole blood samples taken over a period of 24 hours
from the rats of the second group defined with respect to FIG. 12
(administered megestrol acetate orally), a group of rats
administered radiolabeled oral paclitaxel alone and a group of rats
administered cyclosporin orally one hour prior to and again
immediately after radiolabeled oral paclitaxel.
[0037] FIG. 15 is a graph reflecting the levels of radioactivity
detected in whole blood samples taken over a period of 24 hours
from the rats of the third group defined with respect to FIG. 12
(administered ketoconazole orally), a group of rats administered
radiolabeled oral paclitaxel alone and a group of rats receiving
cyclosporin orally one hour prior to and again immediately after
radiolabeled oral paclitaxel.
[0038] FIG. 16 is a graph reflecting the levels of radioactivity
detected in whole blood samples taken over a period of 24 hours
from the rats of the first group defined with respect to FIG. 8
(administered 10 mg/kg of verapamil), the first group defined with
respect to FIG. 12 (administered 100 mg/kg of verapamil), a group
of rats receiving radiolabeled oral paclitaxel alone and a group of
rats receiving cyclosporin orally one hour prior to and again
immediately after radiolabeled oral paclitaxel.
[0039] FIG. 17 is a graph reflecting the levels of radioactivity
detected in whole blood samples taken over a period of 24 hours
from the rats of the second group defined with respect to FIG. 8
(administered progesterone orally), the second group defined with
respect to FIG. 12 (administered megestrol acetate orally), a group
of rats receiving radiolabeled oral paclitaxel alone and a group of
rats receiving cyclosporin orally one hour prior to and again
immediately after radiolabeled oral paclitaxel.
[0040] FIG. 17A is a graph reflecting a comparison of dose response
curves in a group of rats receiving cyclosporin orally one hour
prior to and again immediately after radiolabeled oral paclitaxel
with a group of rats receiving ketoconazole orally one hour prior
to and again immediately after radiolabeled oral paclitaxel. FIG.
17B is a comparison of AUC.sub.0-24 values determined with respect
to the same two groups of rats.
[0041] FIG. 18 is a graph reflecting the levels of radioactivity
detected in whole blood samples taken from three groups of rats
over a period of 24 hours: one group administered only radiolabeled
etoposide IV, a second administered only radiolabeled etoposide
orally and a third administered radiolabeled etoposide orally with
oral cyclosporin doses prior to and immediately after the etoposide
dose, with the ordinate scale running from 0 to 1 whole blood ppm
etoposide equivalents.
[0042] FIG. 19 is a graph reflecting the levels of radioactivity
detected in whole blood samples taken from the three groups of rats
defined with respect to FIG. 18, with the ordinate scale running
from 0 to 0.2 whole blood ppm radiolabeled etoposide
equivalents.
[0043] FIG. 20 is a graph reflecting the mean cumulative % of dose
of radioactivity detected in the feces and urine of three groups of
rats over a period of 168 hours: one group administered only
radiolabeled paclitaxel IV, a second administered only radiolabeled
paclitaxel orally and a third administered radiolabeled paclitaxel
orally with oral cyclosporin doses prior to and immediately after
the paclitaxel dose.
[0044] FIG. 21 is a bar graph reflecting the mean ppm values of
paclitaxel equivalents detected in blood and plasma from the three
groups of rats defined with respect to FIG. 20 168 hours (7 days)
after administration of paclitaxel.
[0045] FIG. 22 is a bar graph reflecting the mean ppm values of
paclitaxel equivalents detected in various tissues (liver, kidney,
testes and carcass) from the three groups of rats defined with
respect to FIG. 20 168 hours (7 days) after administration of
paclitaxel.
[0046] FIG. 23 is a bar graph reflecting the mean ppm values of
paclitaxel equivalents detected in various tissues (muscle,
pancreas, bone, lung and seminal vesicles) from the three groups of
rats defined with respect to FIG. 20 168 hours (7 days) after
administration of paclitaxel.
[0047] FIG. 24 is a bar graph reflecting the mean ppm values of
paclitaxel equivalents detected in various tissues (brain, heart,
G.I. tract, spleen and prostate) from the three groups of rats
defined with respect to FIG. 20 168 hours (7 days) after
administration of paclitaxel.
[0048] FIG. 25 is a graph reflecting the levels of radioactivity
detected in whole blood samples taken from three groups of rats
over a period of 24 hours: one group administered cyclosporin D
orally both one hour before and immediately after an oral dose of
radiolabeled paclitaxel, a second group administered cyclosporin G
orally both one hour before and immediately after an oral dose of
radiolabeled paclitaxel, and a third group administered cyclosporin
A both one hour before and immediately after an oral dose of
radiolabeled paclitaxel.
[0049] FIG. 26 is a graph reflecting the levels of radioactivity
detected in whole blood samples taken from three groups of rats
over a period of 24 hours: one group administered ketoconazole
orally both one hour before and immediately after an oral dose of
radiolabeled paclitaxel, a second group administered a combined
oral dose of cyclosporin A and ketoconazole both one hour before
and immediately after an oral dose of radiolabeled paclitaxel, and
a third group administered cyclosporin A both one hour before and
immediately after an oral dose of radiolabeled paclitaxel.
[0050] FIG. 27 is a graph reflecting the levels of radioactivity
detected in whole blood samples taken from three groups of rats
over a period of 24 hours: one group administered captopril orally
both two hours before and immediately after an oral dose of
radiolabeled paclitaxel, a second group administered cyclosporin A
both one hour before and immediately after an oral dose of
radiolabeled paclitaxel and a third group administered orally
radiolabeled paclitaxel alone.
[0051] FIG. 28 shows the radioactivity profile from an HPLC-plasma
extract from the rats in Group C defined with respect to FIG.
5.
[0052] FIG. 29 is a graph reflecting the levels of radioactivity
detected in whole blood samples taken from four groups of rats over
a period of 24 hours: one group administered 10 mg/kg of
cyclosporin D orally both one hour before and immediately after an
oral dose of radiolabeled paclitaxel, a second group administered
10 mg/kg of cyclosporin F orally both one hour before and
immediately after an oral dose of radiolabeled paclitaxel, a third
group administered 5 mg/kg of cyclosporin D both one hour before
and immediately after an oral dose of radiolabeled paclitaxel, and
a fourth group administered 5 mg/kg of cyclosporin F both one hour
before and immediately after an oral dose of radiolabeled
paclitaxel.
[0053] FIG. 30 is a graph reflecting the levels of radioactivity
detected in whole blood samples taken from three groups of rats
over a period of 24 hours: one (Group A) administered only
radiolabeled docetaxel ("Taxotere") IV, a second (Group B)
administered only radiolabeled docetaxel orally and a third group
(Group C) administered radiolabeled docetaxel orally with oral
cyclosporin doses prior to and immediately after the docetaxel
dose, the ordinate of said graph running from 0-12.0 mean ppm
docetaxel equivalents.
[0054] FIG. 31 is a graph reflecting the levels of radioactivity
detected in whole blood samples taken from the three groups of rats
defined as in FIG. 30 but with the ordinate of said graph running
from 0-2.0 mean ppm docetaxel equivalents.
[0055] FIG. 32 is a graph reflecting the levels of radioactivity
detected in whole blood samples taken from three groups of rats
over a period of 24 hours: one (Group A) administered only
radiolabeled paclitaxel IV, a second (Group B) administered only
radiolabeled paclitaxel orally and a third group (Group C)
administered radiolabeled paclitaxel orally with oral cyclosporin
doses prior to and immediately after the paclitaxel dose.
[0056] FIG. 33 is a graph reflecting the levels of unchanged
radiolabeled paclitaxel detected in whole blood samples taken from
the three groups of rats defined with respect to FIG. 32 from 1-24
hrs. post-dose.
[0057] FIG. 34 is a graph reflecting the levels of unchanged
radiolabeled paclitaxel detected in whole blood samples taken from
0-12 hrs. post-dose from the rats of Group A defined with respect
to FIG. 32 and from a fourth group of rats (Group D) administered
radiolabeled paclitaxel IV with oral cyclosporin doses prior to and
immediately after the paclitaxel dose, the ordinate of said graph
running from 0-30 paclitaxel ppm.
[0058] FIG. 35 is a graph reflecting the levels of unchanged
radiolabeled paclitaxel detected in whole blood samples taken from
1-12 hrs. post-dose from the rats of Group A defined with respect
to FIG. 32 and of Group D defined with respect to FIG. 34, the
ordinate of said graph running from 0.000-5.000 paclitaxel ppm.
[0059] FIGS. 36-41 are process schemes for the extraction and
partitioning of radioactivity from the composite (homogenate) of
various organs of the rats of Groups A and C, respectively, as
defined with respect to FIG. 32.
[0060] FIG. 42 is a graph reflecting the levels of paclitaxel
detected in plasma samples taken at specified time intervals from a
group of ten rats on the third and fourth days of a regimen whereby
they were administered twice daily an oral dose (5 mg/kg) of
cyclosporin and, one hour later, the combination of the same dose
of oral cyclosporin plus oral paclitaxel (3 mg/kg).
DETAILED DESCRIPTION OF THE INVENTION
[0061] The present invention pertains generally to increasing the
oral absorption and bioavailability upon oral administration of
pharmacologically active agents, particularly agents that are
poorly absorbed or not absorbed at all from the gastrointestinal
tract or gut. The preferred embodiments of the invention pertain to
(a) a method for increasing the oral bioavailability of antitumor
agents, in particular paclitaxel (currently marketed as TAXOL.RTM.
by Bristol-Myers Squibb Oncology Division) and its derivatives;
other taxanes; the semi-synthetic paclitaxel analog docetaxel
(N-debenzoyl-N-tert-butoxycarbonyl-10-deacety- l paclitaxel),
produced under the trademark TAXOTERE.RTM. by Rhone-Poulenc Rorer
S.A.; and etoposide; (b) dosage forms and kits for oral
administration of antitumor agents and other drugs heretofore
administered only parenterally; and (c) methods of treatment of
cancer patients with such oral dosage forms or combinations
thereof.
[0062] The phrases "oral bioavailability" and "bioavailability upon
oral administration" as used herein refer to the systemic
availability (i.e., blood/plasma levels) of a given amount of drug
administered orally to a patient.
[0063] Paclitaxel is a natural diterpene product isolated from the
Pacific yew tree (Taxus brevifolia). It is a member of the taxane
family of terpenes. It was first isolated in 1971 by Wani et al.
(J. Am. Chem. Soc. 93:2325, 1971), who characterized its structure
by chemical and X-ray crystallographic methods. One mechanism for
its activity relates to paclitaxel's capacity to bind tubulin,
thereby inhibiting cancer cell growth. Schiff et al., Proc. Natl.
Acad. Sci. USA 77:1561-1565 (1980); Schiff et al., Nature,
277:665-667 (1979); Kumar, J. Biol. Chem. 256: 10435-10441
(1981).
[0064] Paclitaxel has been approved for clinical use in the
treatment of refractory ovarian cancer in the United States
(Markman et al., Yale Journal of Biology and Medicine 64:583, 1991;
McGuire et al., Ann. Intern. Med. 111:273, 1989). It is effective
for chemotherapy for several types of neoplasms including breast
(Holmes et al., J. Nat. Cancer Inst. 83:1797, 1991) and has been
approved for treatment of breast cancer as well. It is a potential
candidate for treatment of neoplasms in the skin (Einzig et al.,
Proc. Am. Soc. Clin. Oncol. 20:46) and head and neck carcinomas
(Forastire et al. Sem. Oncol. 20:56, 1990). The compound also shows
potential for the treatment of polycystic kidney disease (Woo et
al., Nature 368:750, 1994), lung cancer and malaria.
[0065] Paclitaxel is only slightly soluble in water and this has
created significant problems in developing suitable injectable and
infusion formulations useful for anticancer chemotherapy. Some
formulations of paclitaxel for IV infusion have been developed
utilizing CREMOPHOR EL.TM. (polyethoxylated castor oil) as the drug
carrier because of paclitaxel's aqueous insolubility. For example,
paclitaxel used in clinical testing under the aegis of the NCI has
been formulated in 50% CREMOPHOR EL.TM. and 50% dehydrated alcohol.
CREMOPHOR EL.TM. however, when administered intravenously, is
itself toxic and produces vasodilation, labored breathing,
lethargy, hypotension and death in dogs. It is also believed to be
responsible for the allergic-type reactions observed during
paclitaxel administration.
[0066] In an attempt to increase paclitaxel's solubility and to
develop more safe clinical formulations, studies have been directed
to synthesizing paclitaxel analogs where the 2' and/or 7-position
is derivatized with groups that would enhance water solubility.
These efforts have yielded prodrug compounds that are more water
soluble than the parent compound and that display the cytotoxic
properties upon activation. One important group of such prodrugs
includes the 2'-onium salts of paclitaxel and docetaxel,
particularly the 2'-methylpyridinium mesylate (2'-MPM) salts.
[0067] Paclitaxel is very poorly absorbed when administered orally
(less than 1%); see Eiseman et al., Second NCI Workshop on Taxol
and Taxus (September 1992); Stuffness et al. in Taxol Science and
Applications (CRC Press 1995). Eiseman et al. indicate that
paclitaxel has a bioavailability of 0% upon oral administration,
and Stuffness et al. report that oral dosing with paclitaxel did
not seem possible since no evidence of antitumor activity was found
on oral administration up to 160 mg/kg/day. Moreover, no effective
method has been developed to enable the effective administration of
oral paclitaxel (i.e., a method of increasing the oral
bioavailability of paclitaxel) or of other oral taxanes or
paclitaxel analogs such as docetaxel which exhibit antitumor
activity. For this reason, paclitaxel has not until now been
administered orally to human patients, and certainly not in the
course of treating paclitaxel-responsive diseases.
[0068] Docetaxel has become commercially available as TAXOTERE.RTM.
in parenteral form for the treatment of breast cancer. To date no
reference has been made in the scientific literature to oral
absorption of docetaxel in animals or patients.
[0069] Etoposide is a semisynthetic derivative of podophyllotoxin
and is used in the treatment of certain neoplastic diseases,
particularly germ cell cancers (e.g., testicular cancers) and small
cell lung cancers (Loehrer, Sem. Onc., 19, no. 6, supp. 14, pp.
48-52, 1992). It is available in oral dosage form (VEPESID.RTM.
capsules, Bristol-Myers Squibb Oncology) but is not consistently
well-absorbed orally (the mean value of oral bioavailability for
etoposide capsules is approximately 50%).
[0070] Cyclosporins are a group of nonpolar cyclic oligopeptides
(some of which have immunosuppressant activity) produced by the
genus Tolypocladium, including, e.g. Tolypocladium inflatum Gams
(formerly designated as Trichoderma polysporum), Tolypocladium
terricola and other fungi imperfecti. The major component,
cyclosporin A (cyclosporin or CsA), has been identified along with
several other lesser metabolites, for example, cyclosporins B
through Z, some of which exhibit substantially less
immunosuppressive activity than cyclosporin A. A number of
synthetic and semi-synthetic analogs have also been prepared. See
generally Jegorov et al., Phytochemistry, 38: 403-407 (1995). The
present invention comprehends natural, semi-synthetic and synthetic
analogs of cyclosporins.
[0071] Cyclosporins are neutral, lipophilic, cyclic undecapeptides
with molecular weights of about 1200. They are used intravenously
or orally as immunosuppressants, primarily for organ
transplantation and certain other conditions. Cyclosporins,
particularly cyclosporin (cyclosporin A), are known inhibitors of
the P-glycoprotein efflux pump, as well as of certain P450
degradative enzymes, but to date no effective regimens for applying
this property clinically have been developed to the point of
clinical and commercial feasibility or regulatory approval.
[0072] From a mechanistic point of view, orally administered
cyclosporin has the potential to inhibit the P-glycoprotein pump in
the upper small intestine which is the site at which most drugs are
absorbed. With intravenous administration of a drug which is highly
metabolized like cyclosporin, it is not possible for it to appear
intact in that region of the gut where drugs are normally absorbed.
After parenteral administration, cyclosporin is extracted by the
liver and enters the bile and gut distal to this area of optimal
absorption. One of the surprising discoveries of the invention is
that the immunosuppression observed with certain cyclosporins is
not inextricably linked to improvement in oral bioavailability of
therapeutic agents. Thus, cyclosporin F enhances the oral
bioavailability of paclitaxel even though, according to reports in
the literature, it does not display immunosuppressive activity.
Stewart et al., Transplantation Proceedings, 20:(Supp. 3) 989-992
(1988); Granelli-Piperno et al., Transplantation, 46:53S-60S
(1988).
[0073] Ketoconazole is a widely used antifungal imidazole
derivative which has also been used to some extent in the treatment
of prostate carcinoma. Ketoconazole has been shown, as one of its
activities, to reverse MDR in highly resistant human KB carcinoma
cells (Siegsmund et al., J. Urology 151: 485-491, 1994), but also
can inhibit the cytochrome P-450 drug-metabolizing enzymes.
[0074] It has now been discovered that many pharmaceutical agents
with poor oral absorption profiles can be effectively administered
orally with sufficient systemic absorption to exhibit therapeutic
activity levels when said agents are co-administered orally with an
oral dose of certain cyclosporins or other agents known to inhibit
the multidrug resistance, drug transport activity of the
P-glycoprotein intracellular pump, as well as certain enhancing
agents whose ability to inhibit P-glycoprotein transport has not
yet been determined. A further surprising discovery of our
invention is that under some conditions, the oral administration
leads to a more favorable pharmacokinetic profile, better tissue
penetration and higher volume of distribution of the target
therapeutic agent.
[0075] We have observed in animal studies that certain multidrug
resistance suppressing agents such as cyclosporin and ketoconazole,
when administered orally immediately after and/or before drugs such
as paclitaxel and etoposide, increase absorption of the latter
drugs from the gut to an unexpected and surprising degree resulting
in therapeutic levels being achieved. It is not at all clear,
however, that these observed results are due to the suppression of
the P-glycoprotein pump.
[0076] Another possible explanation for the observed increased
bioavailability of paclitaxel and etoposide is that there may be
interaction at the level of the drug metabolizing enzymes for
cyclosporin and paclitaxel. It is known that both agents are highly
metabolized by the cytochrome P-450 system (e.g., P-450 3A), which
is concentrated in the liver as well as the small intestine. It is
conceivable that cyclosporin which was administered first may have
inhibited these enzymes so that paclitaxel, which is non-polar and
lipophilic, could be absorbed. In the absence of this local
inhibition, paclitaxel would be metabolized to more polar
metabolites which would not transverse the mucosal cells. The
failure to demonstrate a pharmacokinetic interaction between
cyclosporin and paclitaxel when cyclosporin was given 3 hr prior to
administration of IV paclitaxel suggests that the site of
interaction was the gut lumen. Even this theoretical explanation
does not account for our surprising discovery that certain
P-glycoprotein inhibitors (e.g., cyclosporins and ketoconazole)
increase oral bioavailability of specific target drugs to a high
degree, whereas other agents known to be active P-glycoprotein
inhibitors exhibit little activity as oral absorption enhancers for
the same target drugs.
[0077] This theorized inhibition of gut metabolism of the target
agent would have little or no effect in increasing systemic blood
levels when the target agent is administered intravenously.
Moreover, since the primary effect of the oral absorption enhancing
agent may be a local effect in the gut lumen, subtherapeutic doses
should be effective in achieving the desired effect. This is an
important consideration in the case of enhancing agents such as
cyclosporins which have powerful immunosuppressant activity and can
present toxicity problems if administered at high dose levels. Our
observation that non-immunosuppressive cyclosporins, such as
cyclosporin F, can still function as an oral enhancer is of great
clinical value.
[0078] It is important to note that while we provide hypotheses as
to the mechanisms of action which underlie our invention, we do not
actually know the mechanism(s) responsible for the surprising
findings discussed herein; and this does not impede one of skill in
the art from practicing the invention described.
[0079] The method of the invention for increasing the oral
bioavailability of a target therapeutic agent with poor oral
bioavailability (average or mean bioavailability 50% or less)
comprises the oral administration of an oral absorption or
bioavailability enhancing agent to a mammalian patient (human or
animal) simultaneously with, or prior to, or both simultaneously
with and prior to the oral administration to increase the quantity
and duration of absorption of the intact target agent into the
bloodstream.
[0080] The orally administered enhancing agents which may be used
in accordance with the invention include, but are not limited to,
the following:
[0081] Cyclosporins, including cyclosporins A through Z but
particularly cyclosporin A (cyclosporin), cyclosporin F,
cyclosporin D, dihydro cyclosporin A, dihydro cyclosporin C, acetyl
cyclosporin A, PSC-833, SDZ-NIM 811.sup.2 (both from Sandoz
Pharmaceutical Corp.), and related oligopeptides produced by
species in the genus Tolypocladium. The structures of cyclosporins
A-Z are described in Table 1 below. .sup.2SDZ-NIM 811 is
(Me-Ile-4)-cyclosporin, an antiviral, non-immunosuppressive
cyclosporin.
[0082] Antifungals--ketoconazole.
[0083] Cardiovascular drugs--MS-209 (from BASF), amiodarone,
nifedipine, reserpine, quinidine, nicardipine, ethacrynic acid,
propafenone, reserpine, amiloride.
[0084] Anti-migraine natural products--ergot alkaloids.
[0085] Antibiotics--cefoperazone, tetracycline, chloroquine,
fosfomycin.
[0086] Antiparasitics--ivermectin.
[0087] Multi-drug resistance reversers--VX-710 and VX-853 (Vertex
Pharmaceutical Incorporated).
[0088] Tyrosine kinase inhibitors--genistein and related
isoflavonoids, quercetin.
[0089] Protein kinase C inhibitors--calphostin.
[0090] Apoptosis inducers--ceramides.
[0091] Agents active against endorphin receptors--morphine,
morphine congeners, other opioids and opioid antagonists including
(but not limited to) naloxone, naltrexone and nalmefene).
[0092] The class of orally administered target therapeutic agents
whose oral absorption is increased by the enhancing agents
includes, but is not limited to, the following:
[0093] Paclitaxel, other taxanes, docetaxel and derivatives and
prodrugs of all of the foregoing, particularly their 2'-MPM salts
and other 2'-methylpyridinium salts.
[0094] Other chemotherapeutic agents which have poor or highly
variable oral bioavailability including etoposide, camptothecin,
CPT-11 (Pharmacia and Upjohn), topetecan (SmithKline Beecham),
doxorubicin, vincristine, daunorubicin, mitoxantrone and
colchicine, all of which are believed to be affected by the
P-glycoprotein efflux.
[0095] Other drugs which have not been shown to be handled by
P-glycoprotein but which can be made orally absorbable in the
presence of an inhibitor of P-glycoprotein in the gut, including
ganciclovir, foscarnet, camptothecin and camptothecin
derivatives.
1TABLE 1 Cyclosporins A-Z Cyclo- sporin Amino acids Cy- 1 2 3 4 5 6
7 8 9 10 11 CyA Mebmt Abu Sar MeLeu Val MeLeu Ala D-Ala MeLeu MeLeu
MeVal CyB Mebmt Ala Sar MeLeu Val MeLeu Ala D-Ala MeLeu MeLeu MeVal
CyC Mebmt Thr Sar MeLeu Val MeLeu Ala D-Ala MeLeu MeLeu MeVal CyD
Mebmt Val Sar MeLeu Val MeLeu Ala D-Ala MeLeu MeLeu MeVal CyE Mebmt
Abu Sar MeLeu Val MeLeu Ala D-Ala MeLeu MeLeu Val CyF Desoxy- Abu
Sar MeLeu Val MeLeu Ala D-Ala MeLeu MeLeu MeVal Mebmt CyG Mebmt Nva
Sar MeLeu Val MeLeu Ala D-Ala MeLeu MeLeu MeVal CyH Mebmt Abu Sar
MeLeu Val MeLeu Ala D-Ala MeLeu MeLeu D-Mev CyI Mebmt Val Sar MeLeu
Val MeLeu Ala D-Ala MeLeu Leu MeVal CyK Desoxy- Val Sar MeLeu Val
MeLeu Ala D-Ala MeLeu MeLeu MeVal Mebmt CyL Bmt Abu Sar MeLeu Val
MeLeu Ala D-Ala MeLeu MeLeu MeVal CyM Mebmt Nva Sar MeLeu Val MeLeu
Ala D-Ala MeLeu MeLeu MeVal CyN Mebmt Nva Sar MeLeu Val MeLeu Ala
D-Ala MeLeu Leu MeVal CyO MeLeu Nva Sar MeLeu Val MeLeu Ala D-Ala
MeLeu MeLeu MeVal CyP Bmt Thr Sar MeLeu Val MeLeu Ala D-Ala MeLeu
MeLeu MeVal CyQ Mebmt Abu Sar Val Val MeLeu Ala D-Ala MeLeu MeLeu
MeVal CyR Mebmt Abu Sar MeLeu Val Leu Ala D-Ala MeLeu Leu MeVal CyS
Mebmt Thr Sar Val Val MeLeu Ala D-Ala MeLeu MeLeu MeVal CyT Mebmt
Abu Sar MeLeu Val MeLeu Ala D-Ala MeLeu Leu MeVal CyU Mebmt Abu Sar
MeLeu Val Leu Ala D-Ala MeLeu MeLeu MeVal CyV Mebmt Abu Sar MeLeu
Val MeLeu Ala D-Ala MeLeu MeLeu MeVal CyW Mebmt Thr Sar MeLeu Val
MeLeu Ala D-Ala MeLeu MeLeu Val CyX Mebmt Nva Sar MeLeu Val MeLeu
Ala D-Ala Leu MeLeu MeVal CyY Mebmt Nva Sar MeLeu Val Leu Ala D-Ala
MeLeu MeLeu MeVal CyZ MeAmino Abu Sar MeLeu Val MeLeu Ala D-Ala
MeLeu MeLeu MeVal octyl- acid
[0096] The dosage range of the enhancing agent to be
co-administered with the target agent in accordance with the
invention is about 0.1 to about 15 mg/kg of patient body weight.
"Co-administration" of the enhancing agent comprehends
administration substantially simultaneously with the target agent
(either less than 0.5 hr. before, less than 0.5 hr. after or
together), from about 0.5 to about 24 hr. before the administration
of the target agent, or both, i.e., with one or more doses of the
same or different enhancing agents given at least 0.5 hr. before
and one dose given substantially simultaneously with (either
together with or immediately before of after) the target agent.
Additionally, "co-administration" comprehends administering more
than one dose of target agent within 24 hrs after a dose of
enhancing agent, in other words, the enhancing agent(s) need not be
administered again before or with every administration of target
agent, but may be administered intermittently during the course of
treatment.
[0097] The dosage range of orally administered target agents will
vary from drug to drug based on its therapeutic index, the
requirements of the condition being treated, the status of the
subject and so forth. The method of the invention makes it possible
to administer paclitaxel orally ranging from about 20 mg/m.sup.2 to
about 1000 mg/m.sup.2 (based on patient body surface area) or about
2-30 mg/kg (based on patient body weight) as single or divided
(2-3) daily doses, and maintain the plasma levels of paclitaxel in
humans in the range of 50-500 ng/ml for extended periods of time
(e.g., 8-12 hours) after each oral dose. These levels are at least
comparable to those achieved with 96-hour IV infusion taxol therapy
(which causes the patient great inconvenience, discomfort, loss of
time, infection potential, etc.). Moreover, such plasma levels of
paclitaxel are more than sufficient to provide the desired
pharmacological activities of the target drug, e.g., inhibition of
tubulin disassembly (which occurs at levels of about 0.1 .mu.M, or
about 85 ng/ml) and inhibition of protein isoprenylation (which
occurs at levels of about 0.03 .mu.M, or about 25 ng/ml) which are
directly related to its antitumor effects by inhibiting oncogene
functions and other signal-transducing proteins that play a pivotal
role in cell growth regulation.
[0098] It may be suitable in some instances to administer to the
subject a higher initial loading dose of the target agent to
achieve peak blood levels, followed by lower maintenance doses.
[0099] Two or more different enhancing agents and/or two or more
different target agents may be administered together, alternately
or intermittently in all of the various aspects of the method of
the invention.
[0100] The present invention also comprehends methods of treating
mammalian patients afflicted with cancers, tumors, Kaposi's
sarcoma, malignancies, uncontrolled tissue or cellular
proliferation secondary to tissue injury, and any other disease
conditions responsive to paclitaxel, taxanes, docetaxel, etoposide,
prodrugs and derivatives of all the foregoing, paclitaxel 2'-MPM,
and docetaxel 2'-MPM with orally administered dosage forms
comprising one or more of those agents. Among the types of
carcinoma which may be treated particularly effectively with oral
paclitaxel, docetaxel, other taxanes, and their prodrugs and
derivatives, are hepatocellular carcinoma and liver metastases, and
cancers of the gastrointestinal tract, pancreas and lung. Examples
of non-cancerous disease conditions which may be effectively
treated with these active agents administered orally in accordance
with the present invention are uncontrolled tissue or cellular
proliferation secondary to tissue injury, polycystic kidney disease
and malaria, including chloroquine- and pyrimethamine-resistant
malaria parasites (Pouvelle et al., J. Clin. Invest. 44: 413-417,
1994).
[0101] The antitumor agents which heretofore were administered only
parenterally can now be administered in accordance with the
invention by the oral route with sufficient bioavailability to
provide pharmacologically active blood concentrations which will be
particularly effective in the treatment of patients with primary
tumors and metastases. The active ingredients will penetrate the
gut wall as a result of the prior and/or concomitant administration
of the MDR inhibitors or other enhancers and will be taken up by
the portal circulation rapidly, providing a higher local initial
concentration of the chemotherapeutic agents in the liver (a far
higher local concentration than is currently achieved with IV
infusion therapy) than in the general systemic circulation or in
most other organs at seven days. Furthermore, it should be noted
that the higher levels of paclitaxel in the liver after oral
administration may not be reflected in increased plasma levels
because of the high first pass effect of the liver. The method of
the invention, in selectively producing high blood concentrations
of antitumor agents, is particularly valuable in the treatment of
liver cancers (e.g., hepatocellular carcinoma and liver
metastases), gastrointestinal cancers (e.g., colon, rectal) and
lung cancers.
[0102] Similarly, after oral administration in accordance with the
present invention higher levels of paclitaxel after twenty-four
hours are found (upon tissue distribution analysis) in the
gastrointestinal tract, pancreas and lung in comparison with the
systemic circulation and most other organs. This fact makes orally
administered paclitaxel of great value in the treatment of cancers
of the G.I. tract, pancreas and lung.
[0103] FIGS. 21-24 are especially noteworthy and surprising. Our
invention, in certain cases, provides a method for achieving
comparable and sometimes higher local tissue concentrations of
paclitaxel via the oral route than the intravenous route. This is
consistent with a higher volume of distribution of the therapeutic
agent. Furthermore, oral administration of an enhancing agent
before and immediately after a target agent has been shown (in the
case of cyclosporin and paclitaxel, see FIG. 20) to produce a
higher concentration of the target agent in the urine than even IV
administration. This should make the oral co-administration of
enhancing agent with target agent a treatment of choice in the case
of patients with tumors or metastases in the genito-urinary
tract.
[0104] Apart from the higher than previously achieved local
concentration of the active ingredients in the liver, the plasma
and tissue distribution of the active target agents administered
orally with the appropriate enhancing agents as provided in the
present invention is remarkably and surprisingly similar to that
observed upon IV administration. A series of studies with
experimental animals showed that steady state plasma levels of
paclitaxel were achieved upon oral co-administration with CsA by
the third day of the regimen. The levels of the target agent
achieved at steady state were comparable to those achieved in
patients by a 96-hour IV infusion of paclitaxel. A 27% response
rate was found in taxane-failure patients with metastatic breast
cancer treated with a continuous 96-hour infusion every three weeks
(Seidman et al., J. Clin. Oncol. 14:1877, 1996). It is believed
that similar results can be achieved with the treatment methods of
the present invention, without the discomfort, inconvenience and
risks of prolonged IV infusions.
[0105] Furthermore, and quite significantly, the elimination-phase
concentration in the blood of paclitaxel and the other antitumor
agents listed above, when administered orally as provided herein,
is approximately equal to that achieved with IV administration, and
these high, therapeutically effective levels, can be maintained for
as long as 8-12 hours after each administration. The increase in
urinary excretion of drug after oral administration in the presence
of CsA not only supports the enhanced oral absorption of paclitaxel
but also provides more drug being delivered to the genito-urinary
tract for the treatment of cancers.
[0106] Oral dosage forms of the target agents whose bioavailability
is increased by the co-administration of the enhancing agents may
be in the form of conventional tablets, capsules, caplets, gelcaps,
pills, liquids (e.g., solutions, suspensions or elixirs), lozenges
and any other oral dosage forms known in the pharmaceutical arts.
The liquid preparations may include, for example, paclitaxel or
other taxane in a vehicle comprising CREMOPHOR EL or other
polyethoxylated castor oil, alcohol and/or a polyoxyethylated
sorbitan mono-oleate (e.g., TWEEN.RTM. 80, ICI Americas, Inc.).
Each dosage form includes an effective amount of a target agent
(for example, effective antitumor or antineoplastic amounts of an
antitumor or antineoplastic agent) and pharmaceutically inert
ingredients, e.g., conventional excipients, vehicles, fillers,
binders, disentegrants, solvents, solubilizing agents, sweeteners,
coloring agents and any other inactive ingredients which are
regularly included in pharmaceutical dosage forms for oral
administration. Many such dosage forms and oral vehicles
immediately after listings of inactive ingredients therefor are set
forth in Remington's Pharmaceutical Sciences, 17th edition (1985).
Each dosage F form also contains a pharmacologically effective
amount, for example, an effective antineoplastic or tumor-reducing
amount, of one of the target drugs.
[0107] Precise amounts of each of the target drugs in the oral
dosage forms will vary depending on the age, weight, disease and
condition of the patient. For example, paclitaxel dosage forms may
contain sufficient quantities of paclitaxel to provide a daily
dosage of about 20-1000 mg/m.sup.2 (based on patient body surface
area) or about 2-30 mg/kg (based on patient body weight) as single
or divided (2-3) daily doses. Etoposide oral dosage forms may
contain sufficient quantities of etoposide to provide a daily
dosage of about 20-200 mg/m.sup.2 (based on average or median
patient body surface area) as single or divided (2-3) daily
doses.
[0108] As already indicated, certain of the target agents are
commercially available in oral dosage forms, despite their
relatively poor or inconsistent oral bioavailability. For example,
VEPESID.RTM. capsules are available containing 50 mg each of
etoposide.
[0109] In establishing a treatment regimen for a particular patient
treated with the oral, target drug-containing dosage forms of the
invention, it is necessary to take into account the increased
bioavailability provided by the concomitant and/or prior oral
administration of the enhancing agents. For example, although the
manufacturer-recommended dosage amount of VEPESID.RTM. capsules in
the treatment of small cell lung cancer is two times the IV dose
rounded to the nearest 50 mg, the increased bioavailability of
etoposide provided by pre- and/or substantially simultaneous
administration of enhancing agents such as cyclosporins, allows a
considerably lower dosage of oral etoposide to be used to provide
the same effective blood levels of the drug, with greater duration
and stability of action and no increase (and perhaps a decrease) in
toxic side effects. With oral administration one can avoid the high
peak blood levels which are responsible for some of the toxicities.
Based on our experimental data (see FIGS. 18 and 19 and Table 6),
which indicate that the oral absorption of etoposide is essentially
complete (about 96%) in the presence of cyclosporin, the oral daily
dosage range for etoposide in the treatment of testicular cancer
should be about 50-100 mg/m.sup.2 and in the treatment of small
cell lung cancer about 35-50 mg/m.sup.2, based on patient body
surface area.
[0110] Dosing schedules for the treatment method of the present
invention, for example, the treatment of paclitaxel-responsive
diseases with oral paclitaxel dosage forms co-administered with
enhancing agents, can likewise be adjusted to account for the
patient's characteristics and disease status. Preferred dosing
schedules for administration of oral paclitaxel are (a) the daily
administration to a patient in need thereof of 1-3 equally divided
doses providing about 20-1000 mg/m.sup.2 (based on body surface
area), with said daily administration being continued for 1-4
consecutive days each 2-3 weeks, or (b) administration for about
one day each week. The former schedule is comparable to use of a
96-hour paclitaxel infusion every 2-3 weeks, which is considered by
some a preferred IV treatment regimen. A preferred dosing schedule
for oral administration of etoposide co-administered with enhancing
agents is the daily administration to a patient in need thereof of
1-3 equally divided doses providing about 50-100 mg/m.sup.2 (based
on body surface area) in the treatment of patients with testicular
cancer and about 35-50 mg/m.sup.2 as a daily dose in the treatment
of small cell lung cancer, with the daily administration being
continued for 5-21 days in each case and with a period of about 2-3
weeks in between each course of treatment.
[0111] Oral administration of powerful chemotherapeutic agents in
accordance with the invention may actually decrease toxic side
effects in many cases as compared with currently utilized IV
therapy. Rather than producing a sudden and rapid high
concentration in blood levels as is usually the case with an IV
infusion, absorption of the active agent through the gut wall
(promoted by the enhancing agents), provides a more gradual
appearance in the blood levels and a stable, steady-state
maintenance of those levels at or close to the ideal range for a
long period of time.
[0112] Pursuant to another aspect of the invention, combination
oral dosage forms are provided which contain fixed quantities of at
least one enhancing agent and at least one target agent. For
example, such dosage forms can consist of tablets, capsules,
caplets, gelcaps, pills, liquids, lozenges and any other
conventional oral dosage forms containing as active ingredients an
effective oral bioavailability enhancing amount of an antitumor or
anti-neoplastic agent, as well as suitable inactive ingredients.
One such combination product includes from about 0.1 to about 15
mg/kg of one or more of cyclosporins A, D, C, F and G, dihydro CsA,
dihydro CsC and acetyl CsA together with about 20 to about 1000
mg/m.sup.2 (based on average patient body surface area) of
paclitaxel, docetaxel, other taxanes or paclitaxel or docetaxel
derivatives such as paclitaxel 2'-MPM or docetaxel 2'-MPM. Another
such dosage form includes about 0.1 to about 15 mg/kg of
cyclosporin or cyclosporin D or F together with about 20 mg/m.sup.2
to 200 mg/m.sup.2 of etoposide.
[0113] The co-administration of enhancing agents with the target
drugs promotes not only the oral bioavailability of those agents
but also enables their use in the treatment of tumors at sites
highly protected by MDR, e.g., the testes and the brain. Another
aspect of the present invention is, thus, a method of delivering
antitumor drugs to tumor sites protected by MDR through the oral
co-administration of enhancing agents and the antitumor agents,
making it possible to treat brain tumors such as glioblastoma
multiforme.
[0114] Yet another aspect of the present invention is a method of
delivering an active paclitaxel metabolite to a disease site at
therapeutic levels to treat paclitaxel-responsive diseases. The
major in vivo metabolites of paclitaxel have been identified,
particularly the following hydroxylated paclitaxel metabolites A, B
and C:
[0115] A: R.sub.1=H, R.sub.2=OH; B: R.sub.1=OH, R.sub.2=H; C:
R.sub.1=OH, R.sub.2=OH
[0116] (Paclitaxel: R.sub.1=H, R.sub.2.dbd.H)
[0117] In certain in vitro tests metabolite B shown above (also
referred to in the literature as metabolite M4) has been found to
have a higher therapeutic index (ratio of toxic concentration level
to effective concentration level) than paclitaxel in some human
tumor cell lines. The invention possibly enables delivery of
enhanced amounts of metabolite B and other active metabolites of
paclitaxel to tumor sites because upon oral administration all of
the administered paclitaxel will pass through the liver and undergo
metabolism by liver microsomes, yielding more of each metabolite in
the systemic circulation than is achieved with IV
administration.
[0118] An additional aspect of the invention relates to kits to be
used in the treatment of mammalian patients suffering from
conditions responsive to any pharmacologically active target agents
whose oral absorption and bioavailability is increased by an
enhancing agent. These kits include one or more oral dosage forms
of at least one enhancing agent and one or more oral dosage forms
of at least one target agent, or one or more dosage forms which
comprise both.
[0119] By way of illustration, a kit of the invention may include
one or more tablets, capsules, caplets, gelcaps or liquid
formulations containing cyclosporin or ketoconazole, and one or
more tablets, capsules, caplets, gelcaps or liquid formulations
containing paclitaxel or etoposide in dosage amounts within the
ranges described above. Such kits may be used in hospitals,
clinics, physician's offices or in patients' homes to facilitate
the co-administration of the enhancing and target agents. The kits
should also include as an insert printed dosing information for the
co-administration of the enhancing and target agents.
[0120] The subject kits may also include combinations of different
enhancing agents and/or combinations of target agents. For example,
a kit may include oral dosage forms respectively containing a
cyclosporin and ketoconazole as enhancing agents, with paclitaxel
alone as the target agent or with a combination of paclitaxel and
another antitumor drug. The second target agent should be (like
paclitaxel) a drug that exhibits poor oral bioavailability but with
co-administration of enhancing agents can achieve therapeutically
effective blood levels upon oral administration. The target agent
may co-exist with the enhancing agent in the same dosage form or
may be in a separate dosage form.
[0121] The following examples illustrate various aspects of the
invention and demonstrate the unexpected, very substantial
increases in the oral absorption of target agents achieved. These
examples are not intended, however, to limit the invention in any
way or to set forth specific enhancing or target agents, dosage
ranges, testing procedures or other parameters which must be used
exclusively to practice the invention.
EXAMPLE 1
[0122] Eighteen (18) healthy Sprague Dawley rats, all weighing from
225-275 grams and approximately six to eight weeks old, were
randomly divided into three groups of six animals. The first group
of six rats received a single IV administration of paclitaxel at a
dose of 9 mg/kg. The second group received a single oral dose of
paclitaxel at 9 mg/kg. The third group received a single oral dose
of cyclosporin at 5 mg/kg, and one hour later the same group
received an oral dose of 5 mg/kg cyclosporin and 9 mg/kg
paclitaxel.
[0123] Blood samples were collected from the tail vein of each rat
at 0.5, 1, 2, 3, 4 and 6 hours after the paclitaxel dose. In the
case of the IV-treated rats of the first group, an additional blood
sample was taken at eight hours after the paclitaxel dose. The
individual samples were centrifuged and the serum was separated.
For each time interval, the six samples per group were composited
to produce a single representative sample. All samples were assayed
for unchanged paclitaxel by LC/MS with a lower limit of
quantitation of 50 pg/ml.
[0124] The results of the study are graphically illustrated in
FIGS. 1 and 2. FIG. 1 compares all three groups of rats while FIG.
2 compares only the second and third groups which received oral
paclitaxel. It may be seen that in the absence of cyclosporin, the
bioavailability of the paclitaxel in serum was less than 1% but it
rose to 6-7% in the third group which received cyclosporin one hour
prior to a paclitaxel/paclitaxel combined dose.
[0125] The following Table 2 sets forth data regarding the area
under the curve (AUC) values determined for the three groups of
rats. These data indicate that the AUC value over six hours in the
case of the third group of rats receiving both paclitaxel and
paclitaxel was almost eight times the AUC for the second group of
rats receiving only oral paclitaxel.
2TABLE 2 Paclitaxel Absolute Bioavailability AUC.sub.O-6 hr IV
AUC.sub.0-6 hr PO (ng .multidot. hr/mL) (ng .multidot. hr/mL)
Absolute F 9230* 80 0.9% Paclitaxel Interaction with Cyclosporin
AUC.sub.0-6 hr PO with AUC.sub.O-6 hr PO Cyclosporin (ng .multidot.
hr/mL) (ng .multidot. hr/mL) Relative F*** 80 629 786% *AUC value
which does not include 1-hr sample point **F =
[AUC.sub.PO/AUC.sub.IV] .times. 100 ***F = [AUC .sub.PO with
Cyclosporin/AUC.sub.PO] .times. 100
EXAMPLE 2
[0126] Forty (40) healthy Sprague Dawley rats with the same
characteristics as those used in the study described in Example 1
were randomly divided into four groups of ten each labeled Groups
A, F, G and H. The following Table 3 indicates the treatment
provided to each of the test groups and the time intervals for each
dosage administration.
3TABLE 3 No. Of Time Dose Route of Group Rats (Hour) Treatment
(mg/kg) Administration A 10 0 paclitaxel 5 oral 1 paclitaxel 9 oral
1 paclitaxel 5 oral F 10 0 paclitaxel 5 oral 1 paclitaxel 9 oral G
10 0 paclitaxel 5 3 paclitaxel 9 IV H 10 0 paclitaxel 9 IV
[0127] Blood samples were collected from the tail vein of each rat
at 0.25, 0.5, 1, 2, 3, 4, 5, 6, 8, 12 and 24 hours after paclitaxel
administration. After appropriate treatment of the samples and the
creation of one composite sample for each group, the plasma from
each sample was assayed for unchanged paclitaxel.
[0128] FIGS. 3 and 4 graphically illustrate the results of this
study. In FIG. 3 a comparison is shown between the concentration
levels achieved over time in Group A, which received a paclitaxel
pre-dose and a combined paclitaxel-paclitaxel dose one hour later,
and Group F, which received a paclitaxel pre-dose and then only
oral paclitaxel one hour later. FIG. 4 reflects a comparison
between the results achieved with Groups G and H, both of which
received paclitaxel IV but with Group G receiving a pre-dose of
oral paclitaxel three hours before the paclitaxel. As indicated in
FIG. 4, the two groups exhibited essentially the identical levels
of paclitaxel in plasma at the same time intervals. Table 4 sets
forth the AUC data for the four groups of rats in this study. While
the AUC values for Groups G and H were essentially the same, the
AUC value for Group A was 25-30% higher than that for Group F,
indicating the value of providing both paclitaxel pre-treatment and
co-administration of paclitaxel with paclitaxel.
4TABLE 4 Bioavailability of Paclitaxel in Plasma Treatment
AUC.sub.O-t F (%) IV (Group H) 24280 IV + CsA Oral.sup.a (Group G)
24137 99.4 Oral + CsA* (Group F) 1097 4.5 Oral + CsA** (Group A)
1393 5.7 .sup.a3 hr prior to paclitaxel *1 hr pretreatment with CsA
**1 hr pretreatment and simultaneously with paclitaxel
EXAMPLE 3
[0129] Eighteen (18) healthy Sprague Dawley rats with the same
characteristics as those used in the study described in Example 1
were randomly divided into three groups of six rats, Groups A, B
and C. Group A was administered radiolabeled paclitaxel IV; Group B
received 3H-radiolabeled paclitaxel orally; and Group C received an
oral dose of paclitaxel followed one hour later by a combined oral
dose of paclitaxel and radiolabeled oral paclitaxel.
[0130] Blood samples were collected from the tail veins of each rat
at the same time intervals as described in Example 2. The samples
were kept in the form of whole blood. In addition, urine samples
were taken from each rat 4-24 hours post-paclitaxel dose. The blood
and urine samples were analyzed for radioactivity.
[0131] A comparison of the paclitaxel levels in the whole blood
samples from Groups A, B and C is set forth in FIG. 5. Comparisons
of the levels for the individual members of Groups B and C are set
forth in FIGS. 6 and 7, respectively.
[0132] In this study, the oral absorption of radioactivity
(expressed as paclitaxel equivalents) in whole blood was about 10%
in the absence of paclitaxel (Group B) and about 40% with
concomitant paclitaxel administration (Group C). This was
determined by measuring the AUC of blood radioactivity after
intravenous and oral radiolabeled paclitaxel. The bioavailability
of paclitaxel was not determined formally in this study because
that would require assaying for unchanged drug at each time point.
At one time point, though, the radioactivity was extracted from
plasma and after standard HPLC it appeared that at least 32% of the
radioactivity in the plasma was unchanged paclitaxel. The
radioactivity profile from the HPLC-plasma extract of Group C
animals, demonstrating predominantly one peak (which is
paclitaxel), is shown in FIG. 28. Set forth below in Table 5 are
AUC, C.sub.max, T.sub.max, and other data generated by this
study.
5TABLE 5 Total Radioactivity for Paclitaxel in Blood/Urine and % of
Radioactivity Extracted as Paclitaxel in Blood PK Parameter IV (A)
PO (B) PO + CsA** (C) AUC.sub.0-24 (.mu.g eq .times. hr/ml) 32.8
3.2 12.1 C.sub.max (.mu.g eq/ml) ND 0.21 0.82 T.sub.max (hr) -- 25
% Dose in urine 2.2 1.9 8.3 (4-24 hr) % Paclitaxel* ND 7.8*** 32***
*% as paclitaxel from extracted RA at 4-hr sample. **CsA given 1 hr
prior to and simultaneously with paclitaxel. ***These numbers are
lower estimates based upon the incomplete extraction procedure.
[0133]
6TABLE 5A Absorption of total radioactivity after oral
administration of .sup.3H-Paclitaxel with/without Cyclosporin (CsA)
in rats (n = 10) Paclitaxel Paclitaxel Paclitaxel PK Parameters IV
Oral Oral + CsA AUC.sub.0-24 hr (.mu.g equiv. hr/mL) 23.8 1.4 8.1
AUC.sub.0-00 (.mu.g equiv. hr/mL) 27.4 4.5 15.0 F (%) based on
AUC.sub.O-24 hr 5.9 34.0 F (%) Based on AUC.sub.0-00 16.4 54.7
Paclitaxel Dose = 9 mg/kg CsA (5 mg/kg 1 hr prior to and
concomitantly with paclitaxel) F = AUC.sub.oral/AUC.sub.iv
[0134]
7TABLE 5B Pharmacokinetic Parameters of Paclitaxel after Oral
Administration with/without Cyclosporin in Rats (n = 10) PK
Parameters IV Dose PO Dose PO + CsA AUC.sub.0-24 hr (.mu.g hr/mL)
20.43 0.314 4.27 AUC.sub.0-.quadrature. (.mu.g hr/mL) 21.02 0.349
5.41 F (%) 1.7 25.7 CL (mL/hr/Kg) 429 440 430 V (mL/Kg) 4236 5029
5958 t1/2 (hr) 6.8 8.1 9.6 (r.sup.2 = 0.95) (r.sup.2 = 0.78)
(r.sup.2 = 0.96) CL = F * Dose/AUC; Dose = 9 mg/kg; F =
AUC.sub.oral/AUC.sub.iv
[0135] In rats that were treated in the manner described in Example
3, AUC for total radioactivity was determined. Based on the ratio
of AUCoral/AUCiv to infinity, oral absorption in the presence of
paclitaxel rose to 54.7% compared to 16.4% in the absence of
paclitaxel (Table 5A). Using a similar analysis for unchanged
paclitaxel in blood, bioavailability of paclitaxel was 25.7% in the
presence of paclitaxel and 1.7% in the absence of paclitaxel (Table
5B). Body clearance was surprisingly similar among the three
treatment groups. Volume of distribution of paclitaxel was enhanced
about 50% more in the group that received paclitaxel and oral
paclitaxel compared to the IV paclitaxel group.
[0136] In Examples 4-5 the following study design was utilized:
Sprague-Dawley rats with the same characteristics as those used in
the study described in Example 1 were divided into three groups of
three male rats each. All of the rats were fasted 12-14 hours prior
to dosing. At the end of the fasting period, those rats receiving
enhancing agents were administered those agents, and one hour later
received a dose of radiolabeled (.sup.3H) paclitaxel (9 mg/kg) with
concomitant doses of enhancing agent. The rats not receiving
enhancing agents were administered the radiolabeled paclitaxel
after fasting.
[0137] Blood was collected from each animal at 0.5, 1, 2, 3, 4, 5,
6, 7, 8, 12 and 24 hours following the paclitaxel dosing. Urine was
collected from 4-24 hours post dose. Total radioactivity in blood
and urine was then determined for each rat and mean values were
calculated for each group.
EXAMPLE 4
[0138] Three groups of rats were administered, respectively, 10
mg/kg of verapamil orally, 5 mg/kg of progesterone orally and 10
mg/kg of dipyridamole orally as enhancing agents, both alone and
one hour later with an oral dose of paclitaxel. A graphical
comparison of the whole blood concentration-time profile (measured
as concentration equivalents versus time) determined for the three
groups is set forth in FIG. 8. The data reflect roughly similar
results with the use of verapamil and dipyridamole as enhancing
agents, with markedly lower bioavailability achieved with
progesterone.
[0139] FIG. 9 sets forth a graphical comparison between the
concentration-time profile of paclitaxel determined for the group
of rats administered verapamil (10 mg/kg) as an enhancing agent
with the values determined in a prior study for animals
administered oral paclitaxel (9 mg/kg) alone and another group
administered oral paclitaxel (5 mg/kg) both one hour before and
again immediately after a dose of oral paclitaxel (9 mg/kg). The
group receiving paclitaxel achieved far higher blood levels than
the other groups throughout almost the entire 24-hour period.
[0140] FIGS. 10 and 11 represent parallel graphical comparisons to
FIG. 9, but with the values for the progesterone-administered group
shown in FIG. 10 and the dipyridamole group shown in FIG. 11 in
place of the verapamil group of FIG. 9.
EXAMPLE 5
[0141] Three groups of rats were administered, respectively, 100
mg/kg of verapamil orally, 5 mg/kg of megestrol acetate orally and
50 mg/kg of ketoconazole orally as enhancing agents, both alone and
one hour later with an oral dose of radiolabeled paclitaxel. A
graphical comparison of the whole blood concentration-time profile
(measured as concentration equivalents versus time) determined for
the three groups is set forth in FIG. 12. The data reflect roughly
similar results for verapamil and megestrol acetate as enhancing
agents, with markedly higher bioavailability achieved with
ketoconazole in the first 12 hours.
[0142] FIG. 13 sets forth a graphical comparison between the
concentration-time profile of radioactivity determined for the
group of rats administered verapamil (100 mg/kg) as an enhancing
agent with the values determined in a prior study for animals
administered oral paclitaxel (9 mg/kg) alone and another group
administered oral cyclosporin (5 mg/kg) both one hour before and
again immediately after a dose of oral radiolabeled paclitaxel (9
mg/kg).
[0143] FIGS. 14 and 15 represent parallel graphical comparisons to
FIG. 13, but with the values for the megestrol acetate-administered
group shown in FIG. 14 and the ketoconazole group shown in FIG. 15
in place of the verapamil group of FIG. 13.
[0144] FIG. 16 sets forth graphical comparisons between the
concentration-time profiles of radioactivity determined for the
group of rats administered 10 mg/kg of verapamil in Example 4 and
the group administered 100 mg/kg of verapamil in Example 5.
[0145] FIG. 17 sets forth graphical comparisons between the
concentration-time profiles of radioactivity determined for the
group of rats administered 5 mg/kg of progesterone in Example 4 and
the group administered 5 mg/kg of megestrol acetate in Example
5.
[0146] In both FIGS. 16 and 17 there are also shown the same
profiles reflected in FIGS. 13-15 for study groups receiving oral
radiolabeled paclitaxel alone and oral radiolabeled paclitaxel
immediately after and one hour after 5 mg/kg of cyclosporin.
[0147] Exploration of dose-response data for cyclosporin was
performed. Increasing the dose to 10 mg/kg and 20 mg/kg one hour
before and concomitantly with paclitaxel resulted in oral
absorption of radioactivity to about 45%. This can be contrasted
with the findings for ketoconazole in which doses of up to 50 mg/kg
were given one hour before and concomitantly with paclitaxel and
resulted in no further increase in oral absorption of radioactivity
(see FIGS. 17A and 17B).
[0148] The mean pharmacokinetic parameters for the study groups of
animals discussed in Examples 4 and 5 are set forth in Table
6..sup.3 .sup.3The study of Example 4 is identified in Table 6 as
protocol NP951202, and the study of Example 5 is identified as
protocol NP960101.
[0149] The data generated by the studies of Examples 4 and 5 and
reflected in Table 6 and FIGS. 8-17B clearly indicate the efficacy
of cyclosporin as an oral bioavailability enhancing agent and its
superiority to high or low dose verapamil, progesterone or
megestrol acetate, particularly in the first 12 hours after
paclitaxel dosing. They also indicate that ketoconazole, while not
as effective as cyclosporin, also has significant activity in
promoting the oral absorption of paclitaxel.
8TABLE 6 Mean Pharmacokinetic Parameters For NP951202 and NP960101
AUCO-24 Study Dose/Route (ug .times. t1/2 Cmax Protocol Treatment
(mg/kg) hr/mL) F % (hour) (ug*eq/mL) NP951001 Paclitaxel 9/IV .sup.
32.04 20.15 37 only Paclitaxel .sup. 9/PO .sup. 3.24 10.1 18.86
0.21 only Cyclo- .sup. 5/PO(c), 12.02 37.5 14.51 0.82 sporin
9/PO(P) 5/PO(C).sup. NP951202 Verapamil 10/PO(V),.sup. 6.34 19.8
24.4 0.78 9/PO(P) 10/PO(V).sup. Pro- 5/PO(Pro),.sup. 3.78 11.8 20.0
0.26 gesterone 9/PO(P) 5/PO(Pro) Dipyri- 10/PO(D),.sup. 6.18 19.3
26.6 0.46 damole 9/PO(P) 10/PO(D).sup. NP960101 *Verapamil
100/PO(V), NA NA NA 0.44 (animals 9/PO(P) died) 100/PO(V) Magace
.sup. 5/PO(M), 5.19 16.2 23.1 0.44 9/PO(P) .sup. 5/PO(M) Keto-
50/PO(K),.sup. 8.03 25.1 9.23 0.69 conazole 9/PO(P)
50/PO(K).sup.
EXAMPLE 6
[0150] Three groups of three male rats each were fasted 16-18 hours
prior to dosing. At the end of the fasting period one group of rats
was administered an oral dose of 5 mg/kg of cyclosporin. One hour
later, that group was administered 5 mg/kg of cyclosporin orally
with 1 mg/kg of 3H-radiolabeled etoposide orally. The other two
groups were administered after fasting only 1 mg/kg of 3H-etoposide
IV and 1 mg/kg H-etoposide orally, respectively. The procedures for
blood and urine collection and for determining total radioactivity
were the same as in Examples 4 and 5 except that blood was taken at
two additional intervals from the group receiving etoposide IV, at
0.033 and 0.25 hours. The resultant data are set forth in Table
7.
[0151] FIGS. 18 and 19 set forth graphically the mean whole blood
concentration-time profile of etoposide determined for the three
study groups. In FIG. 18 the ordinate scale runs from 0-1 etoposide
concentration equivalents (ppm), while in FIG. 19 the ordinate
scale runs from 0-0.2 etoposide equivalents (ppm) to more clearly
illustrate the differences between the values achieved for the
three groups.
[0152] The data set forth in Table 7 and FIGS. 18 and 19
demonstrate the efficacy of cyclosporin as an oral bioavailability
enhancing agent for etoposide, particularly in the first 12 hours
after dosing.
9TABLE 7 Mean Pharmaconkinetic Parameters For NP960102 AUCO-24
Study Dose/Route (ug .times. t1/2 Cmax Protocol Treatment (mg/kg)
hr/mL) F % (hour) (ug*eq/mL) NP960102 Grp A Etoposide 1/IV 1.08
26.5 2.16 only Grp B Etoposide 1/PO 0.61 56.5 19.1 0.03 only Grp C
CsA, 5/PO(C), 1.04 96.3 18.1 0.12 Etoposide + 1/PO(P) CsA
5/PO(C)
EXAMPLE 7
[0153] In another series of studies, three groups of three male
rats each were fasted 16-18 hours prior to dosing. At the end of
the fasting period one group of rats was administered an oral dose
of ketoconazole (2 mg/kg). One hour later, that group was
administered 2 mg/kg of ketoconazole orally with 1 mg/kg of
3H-radiolabeled etoposide orally. The other two groups were treated
in the same fashion except that they were administered 10 and 50
mg/kg of ketoconazole, respectively, after fasting prior to and
just after 3H-etoposide orally. The procedures for blood collection
and for determining total radioactivity were the same as in
Examples 4 and 5. The resultant data are set forth in Table 7A.
Thus, in contrast to the effect that cyclosporin had on nearly
doubling the oral absorption of paclitaxel-derived radioactivity,
ketoconazole administered over a wide range of doses did not
enhance the oral absorption of etoposide compared to etoposide
alone.
10TABLE 7A NP960501 GrpA Etoposide + 1/EO(2/Keto) 0.54 50.39 0.026
1 47.8 Keto- conazole GrpB Etoposide + 1/EO(10/Keto) 0.69 63.95
0.032 24 -91.5 Keto- conazole GrpC Etoposide + 1/EO(50/Keto) 0.64
58.91 0.060 4 38.1 Keto- conazole
EXAMPLE 7
[0154] An excretion balance study for paclitaxel in rats was
conducted. Three groups of 4-5 male rats each were fasted 12-14
hours prior to dosing. At the end of the fasting period one group
of rats was administered an oral dose of 5 mg/kg of cyclosporin.
One hour later, that group was administered 5 mg/kg of cyclosporin
orally with 9 mg/kg of radiolabeled paclitaxel orally. The other
two groups were administered after fasting only 9 mg/kg of
radiolabeled paclitaxel IV and 9 mg/kg of radiolabeled paclitaxel
orally.
[0155] The urine and feces were collected from each animal at the
following intervals: 0-2, 2-4, 4-8, 8-12, 12-24, 24-36, 36-48,
48-72, 72-96, 96-120, 120-144, and 144-168 hours post-dose. Tissue
collection was performed at 168 hours post-dose. The procedure for
determining total radioactivity was the same as in Examples 4 and
5.
[0156] FIG. 20 sets forth a graphical comparison of the mean
cumulative percentage of dose of paclitaxel detected in the feces
and urine of the test animals over the 168-hour period. The group
of rats administered cyclosporin both before and with the oral
paclitaxel exhibited a markedly lower percentage of dose in feces
than the other two groups and a significantly higher percentage of
dose in urine, indicating that substantially more of the oral
paclitaxel diffused through the gut wall and entered the systemic
circulation of the animals in the cyclosporin treated group. In
addition, the fact that the percentage of dose in urine was
significantly higher for the rats administered oral cyclosporin and
paclitaxel in comparison with the IV-paclitaxel group indicates
that the concomitant oral administration caused a higher
concentration of radioactivity to pass through the genito-urinary
tract.
[0157] FIGS. 21-24 are bar graphs reflecting the mean ppm values of
paclitaxel detected in a variety of tissues harvested from the rats
in the three study groups, Group A representing the animals
administered paclitaxel IV, Group B representing those administered
paclitaxel orally and Group C representing the treated-treated
group. These graphs show that the levels of paclitaxel found in the
various tissues from the rats in Group C were roughly comparable to
the levels observed in the rats from Group A that received
paclitaxel IV, except in the liver where the level of paclitaxel
was more than twice as high in the treated group as in the group
administered paclitaxel IV. The levels detected in the tissues of
the rats of Group B (administered oral paclitaxel alone) were quite
low, in most instances far less than half of the levels in either
of the other groups.
[0158] The data resulting from this study are set forth in Tables 8
and 9.
11TABLE 8 Excretion Balance Study for Paclitaxel in Rat Sample
Group A Group B Group C Urine 9.160 6.660 18.350 Feces 79.660
84.410 61.250 Tissues 1.710 0.600 1.430 Total 90.530 91.670
81.030
[0159]
12TABLE 9 EXCRETION BALANCE STUDY FOR PACLITAXEL IN RAT Radioactive
Residues in Tissues Expressed as PPM (Mean Values) SAMPLE GROUP A
GROUP B GROUP C Brain 0.101 0.029 0.096 Heart 0.085 0.025 0.088
Lung 0.143 0.030 0.136 Liver 0.237 0.074 0.566 Kidney 0.180 0.032
0.119 Muscle 0.079 0.025 0.080 GI Tract 0.083 0.021 0.055 Testes
0.346 0.037 0.217 Pancreas 0.078 0.018 0.080 Carcass 0.143 0.053
0.099 Bone 0.035 0.007 0.034 Spleen 0.101 0.024 0.083 Prostate
0.081 0.022 0.090 S. Vesicles 0.121 0.024 0.094 Blood 0.112 0.034
0.106 Plasma 0.126 0.038 0.124
EXAMPLE 9
[0160] Another tissue distribution study for paclitaxel in rats was
conducted. Two groups of 10 male rats each were fasted 12-14 hours
prior to dosing. At the end of the fasting period one group of rats
was administered an oral dose of 5 mg/kg cyclosporin. One hour
later, that group was administered 5 mg/kg of cyclosporin orally
with 9 mg/kg of radiolabeled paclitaxel orally. The other group was
administered after fasting only 9 mg/kg of radiolabeled paclitaxel
IV.
[0161] Tissue collection was performed at 24 hours post-dose. The
procedure for determining total radioactivity was the same as in
Examples 4 and 5.
[0162] Table 9A reflects the ppm values of paclitaxel-derived
radioactivity detected in a variety of tissues harvested from the
rats in the two study groups. One group representing the animals
administered paclitaxel IV and the second group representing those
administered paclitaxel with cyclosporin given 1 hour prior to and
immediately after paclitaxel. The levels of paclitaxel found in the
various tissues from the treated-treated rats were roughly
comparable to the levels observed in the rats given paclitaxel IV,
except in the spleen, pancreas and gastrointestinal tract where the
level of paclitaxel was about twice as high in the treated-treated
group as in the group administered paclitaxel IV.
[0163] A comparison of unchanged paclitaxel concentrations in
various organs after IV paclitaxel alone compared to oral
paclitaxel given in the presence of treated is shown in Table 9B.
Higher concentrations of unchanged paclitaxel after oral
administration were found in the lungs and gastrointestinal tract,
compared to the IV route of administration.
13TABLE 9A Ratio of ppm Paclitaxel Equivalents in Tissue for Group
C and A (Mean Values) Oral Dose Tissue with CsA IV Dose Ratio Brain
0.267 0.284 0.94 Heart 1.166 0.576 2.02 Lung 2.076 1.230 1.69 Liver
4.328 3.685 1.17 Kidney 2.325 1.259 1.85 Muscle 0.951 0.639 1.49 GI
Tract 11.282 5.673 1.99 Testes 0.435 0.804 0.54 Pancreas 1.999
0.911 2.19 Carcass 1.043 0.858 1.22 Bone 1.057 0.612 1.73 Spleen
3.089 1.180 2.62 Prostate 2.212 1.660 1.33 Seminal Vesicles 1.891
2.693 0.70 Blood 0.373 0.401 0.93 Plasma 0.370 0.347 1.07
[0164]
14TABLE 9B Extraction of Radioactivity from Various Tissues % of
.sup.3H Tissue % of .sup.3H Tissue Characterized Paclitaxel
Characterized Group Tissue ppm .sup.3H by HPLC ppm as Paclitaxel IV
Liver 3.7 75.9 1.34 36.2 Lung 1.3 79.5 0.82 63.1 GI 5.4 78.1 1.55
28.7 Tract Oral Liver 4.6 75.5 0.93 20.7 with CSA Lung 2.3 91.3
1.42 61.7 GI 10.6 91.4 5.17 48.8 Tract 1.0 Liver 1.0 102.7 0.77
77.0 ppm Spike
EXAMPLE 10
[0165] The procedure of Examples 4 and 5 was followed, but the
three groups of three male rats each were orally administered
respectively 5 mg/kg doses of cyclosporin D, cyclosporin G and
cyclosporin A, both alone and one hour later immediately after an
oral dose of 9 mg/kg radiolabeled paclitaxel. FIG. 25 sets forth a
graphical comparison of the whole blood concentration-time profiles
for radioactivity determined in these three test groups. While all
three cyclosporins showed substantial activity in promoting oral
absorption of paclitaxel, the cyclosporin D, which has the least
immunosuppressive activity (Jeffery, Clin. Biochem, 24:15-21
(1991)), of the three cyclosporins tested, exhibited the greatest
bioavailability enhancing activity.
EXAMPLE 11
[0166] A number of studies were conducted wherein the procedure
used in Examples 4 and 5 was followed, and groups of three male
rats each were orally administered 5-10 mg/kg of various
cyclosporins alone and then again one hour later immediately after
an oral dose of 9 mg/kg radiolabeled paclitaxel. Table 10 sets
forth a comparison of AUC and % absorption from these studies, each
identified by a protocol number beginning with the prefix "NP".
15TABLE 10 AUC & % Absorption of Various Cyclosporins
AUC.sub.0-24 Dose (.mu.g eq. % Protocol Cyclosporin (mg/kg) hr/ml)
Absorption N 96050 A 2 .times. 5 13.91 42.1 96050 A 2 .times. 10
10.17 33.6 96050 A 2 .times. 20 14.63 48.3 N 96050 Acetyl A 2
.times. 5 8.39 25.4 96050 C 2 .times. 5 11.39 34.5 96050 E 2
.times. 5 5.96 18.0 96050 H 2 .times. 5 6.00 18.1 96050 U 2 .times.
5 5.02 15.2 N 96010 D 2 .times. 5 15.92 48.2 96010 G 2 .times. 5
13.22 40.0 N 96070 D 2 .times. 10 14.23 43.1 96070 F 2 .times. 10
11.99 36.3 N 96060 F 2 .times. 5 8.99 27.2 96060 Dihydro A 2
.times. 5 8.5 25.7 N 96080 Leu.sup.4 2 .times. 5 7.38 24.6 96080
Dihydro C 2 .times. 5 13.09 45.1
EXAMPLE 12
[0167] The procedure of Examples 4 and 5 was followed, but the
three groups of three male rats each were orally administered
respectively a 5 mg/kg dose of cyclosporin A, 50 mg/kg ketoconazole
and 5 mg/kg cyclosporin A plus 50 mg/kg ketoconazole, both alone
and one hour later immediately after an oral dose of 9 mg/kg
radiolabeled paclitaxel. A graphical comparison of the results
achieved is set forth in FIG. 26. The group receiving the
combination of ketoconazole and cyclosporin A unexpectedly
exhibited significantly higher blood radioactivity levels over
almost the entire 24-hour period than the groups receiving only one
of these enhancing agents.
EXAMPLE 13
[0168] The procedure of Examples 4 and 5 was followed, but the
three groups of three male rats each were orally administered
respectively a 100 mg/kg dose of captopril both alone and two hours
later immediately after an oral dose of 9 mg/kg radiolabeled
paclitaxel, a 5 mg/kg dose of treated alone and again one hour
later immediately after a 9 mg/kg oral dose of radiolabeled
paclitaxel, and a 9 mg/kg oral dose of radiolabeled paclitaxel
alone. A graphical comparison of the results achieved is set forth
in FIG. 27.
[0169] The aforedescribed studies produced several previously
unknown and unexpected findings which are all of great significance
to the clinical management of many diseases, particularly various
types of cancer:
[0170] Certain MDR (P-glycoprotein) inhibitors as well as other
agents not known to be MDR inhibitors can be administered orally to
effectively enhance the oral bioavailability of treatment agents
which have until now been administered only parenterally because
therapeutic blood levels cannot be attained upon oral
administration.
[0171] Co-administration of the enhancing agents of the invention
with target drugs having poor oral bioavailability can achieve
sustained blood levels of the target drugs comparable to that
achieved with IV infusion therapy but with a less abrupt initial
rise in blood levels and hence less likelihood of toxic side
effects.
[0172] The oral co-administration of the enhancing agents and
target drugs increases the proportionate concentration of the
target agent in the liver, lung and gastrointestinal tract in
comparison with IV administration, making the novel method of
administration particularly useful in the treatment of liver tumors
and metastases.
[0173] Administering an enhancing agent orally prior to
administration of concomitant oral doses of enhancing agent and
target drug increases the oral bioavailability of the target drug
to a significantly higher degree than co-administration of the
enhancing and target agents with no preadministration of enhancing
agent. This results in plasma levels of the target drug reaching
therapeutic levels.
[0174] Cyclosporins, particularly cyclosporins A, D and F, are much
more effective agents for enhancing the bioavailability of
antitumor agents than MDR inhibitors such as verapamil and
progesterone. Ketoconazole has clinically significant oral
bioavailability-enhancing activity, but less than the
cyclosporins.
[0175] In general, the various aspects of the invention enable and
make practical for the first time the administration of oral dosage
forms of widely used pharmaceutical agents, particularly
anti-cancer drugs such as paclitaxel related taxanes and etoposide,
which until now could only be administered effectively or reliably
by IV infusion. The use of such oral dosage forms in the clinical
management of cancers will promote patient comfort, convenience,
compliance and safety and result in cost savings to patients,
hospitals and government and private medical insurers.
[0176] In addition, the teachings of the invention set forth herein
provide information regarding the selection of target and enhancing
agents as well as timing, schedules and dosing. This information
and the methods and compositions of the invention provide
clinicians with procedures for sustaining therapeutic levels of
drugs which require narrow windows of drug concentrations while
avoiding unnecessary and frequently harmful peaks and valleys in
blood concentration levels. In addition, increased volume of
distribution of paclitaxel in the presence of treated, suggests
more drug would be available for anti-tumor activity.
[0177] Apart from multi-drug resistance resulting from
P-glycoprotein encoded by the MDR1 gene, there is another gene
which has recently been found to confer a multi-drug resistance
phenotype in certain laboratory systems: the gene for
multi-drug-resistance-associated protein, MRP (e.g., Zaman et al.,
Proc. Natl. Acad. Sci. USA 91: 8822-8826, 1994).
[0178] Less is known about this new gene and its protein product, a
190-kd membrane bound glycoprotein. Although both the MRP and MDR1
genes encode membrane glycoproteins that can act as transporters of
multiple drugs, there are differences in function, likely
substrates, and prognostic significance between these two genes.
For example MRP but not MDR1 gene expression is a good marker of
poor clinical outcome in patients with neuroblastomas. The putative
function of the MRP-related proteins is to serve as an efflux pump
for glutathione S-conjugates. Thus, molecules that undergo
glutathione conjugation would be susceptible to the action of the
MRP-related system.
[0179] The oral bioavailability of pharmacologically active agents
(or exposure of the tumor to such agents) which are subject to
resistance by MRP-related proteins can be enhanced by orally
co-administrating MRP inhibitors. The preferred embodiment of this
method of increasing oral bioavailability is the oral
administration of one or more MRP inhibitors prior to the oral
co-administration of one or more MRP inhibitors and one or more
target agents subject to MRP-related resistance.
[0180] Examples of target agents of this type include (but are not
limited to) vinca alkaloids (e.g., vincristine), anthracyclines,
epidophyllotoxins (e.g., etoposide) and various taxanes. Examples
of MRP inhibitors that can increase oral bioavailability of target
agents include, but are not limited to, cyclosporins, ketoconazole
and the experimental drugs VX-710 and VX-853 (Vertex
Pharmaceuticals, Inc., Cambridge, Mass.). The structures of VX-710
and VX 853, as well as many related compounds, are disclosed in
U.S. Pat. No. 5,192,773.
[0181] Another method of improving the oral bioavailability of
agents subject to MRP-related resistance is to co-administer with
those agents glutathione or substances which form
glutathione-conjugated products which would interfere with the
functioning of the MRP system and enhance the absorption of the
target agents from the gut, or increase the systemic exposure of
agents subjected to MRP-related transport.
[0182] Yet another system capable of conferring multi-drug
resistance is the so-called Lung Resistance-Related Protein (LRP),
because it was first identified in a multi-drug resistant lung
cancer cell line. This protein is the major structural protein of
the so-called vault apparatus, a large abundant cytoplasmic
ribonucleoprotein particle, which has been conserved from slime
mold to man. Inhibition of this system may also positively affect
oral bioavailability of certain agents. LRP is found in highest
expression in epithelial cells with secretory and excretory
functions, as well as in cells chronically exposed to xenobiotics,
such as bronchial and intestinal lining cells (Scheffer et al.,
Nature Medicine 1: 578-582, 1955). Therefore, this system could
also serve as a target for enhancing oral bioavailability.
[0183] It has thus been shown that there are provided methods,
compositions and kits which achieve the various objects of the
invention and which are well adapted to meet the conditions of
practical use.
[0184] As various possible embodiments might be made of the above
invention, and as various changes might be made in the embodiments
set forth above, it is to be understood that all matters herein
described are to be interpreted as illustrative and not in a
limiting sense.
[0185] What is claimed as new and desired to be protected by
Letters Patent is set forth in the following claims.
* * * * *