U.S. patent application number 12/647872 was filed with the patent office on 2010-04-29 for methods of treating fibromyalgia syndrome, chronic fatigue syndrome and pain.
This patent application is currently assigned to Cypress Bioscience, Inc.. Invention is credited to Jay D. Kranzler, Srinivas G. Rao.
Application Number | 20100105778 12/647872 |
Document ID | / |
Family ID | 21844050 |
Filed Date | 2010-04-29 |
United States Patent
Application |
20100105778 |
Kind Code |
A1 |
Kranzler; Jay D. ; et
al. |
April 29, 2010 |
METHODS OF TREATING FIBROMYALGIA SYNDROME, CHRONIC FATIGUE SYNDROME
AND PAIN
Abstract
The present invention provides a method of treating fibromyalgia
syndrome (FMS), chronic fatigue syndrome (CFS), and pain in an
animal subject. The method generally involves administering a
therapeutically effective amount of a dual serotonin norepinephrine
reuptake inhibitor compound or a pharmaceutically acceptable salt
thereof, wherein said dual serotonin norepinephrine reuptake
inhibitor compound is characterized by a non-tricyclic structure
and an equal or greater inhibition of norepinephrine reuptake than
serotonin reuptake. In particular, the use of milnacipran to treat
FMS, CFS, and pain is disclosed.
Inventors: |
Kranzler; Jay D.; (La Jolla,
CA) ; Rao; Srinivas G.; (San Diego, CA) |
Correspondence
Address: |
FINNEGAN, HENDERSON, FARABOW, GARRETT & DUNNER;LLP
901 NEW YORK AVENUE, NW
WASHINGTON
DC
20001-4413
US
|
Assignee: |
Cypress Bioscience, Inc.
|
Family ID: |
21844050 |
Appl. No.: |
12/647872 |
Filed: |
December 28, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12035820 |
Feb 22, 2008 |
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12647872 |
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10623431 |
Jul 18, 2003 |
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12035820 |
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10028547 |
Dec 19, 2001 |
6602911 |
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10623431 |
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10014149 |
Nov 5, 2001 |
6635675 |
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10028547 |
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Current U.S.
Class: |
514/620 |
Current CPC
Class: |
A61K 31/00 20130101;
A61P 19/04 20180101; A61K 31/135 20130101; A61P 25/00 20180101;
A61P 3/10 20180101; A61K 31/165 20130101; A61K 31/135 20130101;
A61K 2300/00 20130101; A61K 31/165 20130101; A61K 2300/00
20130101 |
Class at
Publication: |
514/620 |
International
Class: |
A61K 31/165 20060101
A61K031/165; A61P 25/00 20060101 A61P025/00 |
Claims
1-25. (canceled)
26. A method of treating neuropathic pain comprising orally
administering to a patient in need thereof a therapeutically
effective amount of milnacipran or a pharmaceutically acceptable
salt thereof.
27. The method of claim 26, wherein the neuropathic pain is
diabetic neuropathy.
28. The method of claim 27, wherein the diabetic neuropathy is
diabetic peripheral neuropathy.
29. The method of claim 27, wherein the diabetic neuropathy is
diabetic autonomic neuropathy.
30. The method of claim 27, wherein the diabetic neuropathy is
diabetic proximal neuropathy.
31. The method of claim 27, wherein the diabetic neuropathy is
diabetic focal neuropathy.
32. The method of claim 26, wherein the milnacipran, or a
pharmaceutically acceptable salt thereof, is administered alone or
in combination with a compound that is not phenylalanine, tyrosine
or tryptophan.
33. The method of claim 26, wherein the milnacipran, or a
pharmaceutically acceptable salt thereof, is administered in
combination with gabapentin, pregabalin, pramipexole, L-DOPA,
amphetamine, tizanidine, clonidine, tramadol, morphine, a tricyclic
antidepressant, codeine, carbamazepine, sibutramine, valium or
trazadone.
34. The method of claim 26, wherein the amount administered is from
about 25 mg to about 400 mg per day.
35. The method of claim 26, wherein the amount administered is from
about 100 mg to about 250 mg per day.
36. The method of claim 26, wherein the amount administered is
about 100 mg per day.
37. The method of claim 26, wherein the amount administered is
about 200 mg per day.
38. The method of claim 36, wherein the amount is administered as a
50 mg dose twice per day.
39. The method of claim 37, wherein the amount is administered as a
100 mg dose twice per day
Description
1. FIELD OF THE INVENTION
[0001] The present invention relates to methods for the treatment
of fibromyalgia syndrome, chronic fatigue syndrome, and pain. In
particular, the present invention relates to methods of treating
fibromyalgia syndrome, chronic fatigue syndrome, and pain with a
sub-class of dual serotonin norepinephrine reuptake inhibitors
characterized by a non-tricyclic structure and inhibit the reuptake
of norepinephrine to an equal or greater extent than they inhibit
the reuptake of serotonin.
2. BACKGROUND OF THE INVENTION
[0002] Fibromyalgia syndrome (FMS) is the most frequent cause of
chronic, widespread pain, estimated to affect 2-4% of the
population. FMS is characterized by a generalized heightened
perception of sensory stimuli. Patients with FMS display
abnormalities in pain perception in the form of both allodynia
(pain with innocuous stimulation) and hyperalgesia (increased
sensitivity to painful stimuli). The syndrome, as defined by the
American College of Rheumatology's criteria, involves the presence
of pain for over 3 months duration in all four quadrants of the
body, as well as along the spine. In addition, pain is elicited at
11 out of 18 "tender points" upon palpation. Other associated
symptoms include fatigue, nonrestorative sleep, and memory
difficulties.
[0003] Chronic fatigue syndrome (CFS) is a debilitating disorder
characterized by profound tiredness or fatigue. Patients with CFS
may become exhausted with only light physical exertion, and must
often function at a level of activity substantially lower than
their capacity before the onset of illness. In addition to the key
defining characteristic of fatigue, CFS patients generally report
various nonspecific symptoms, including weakness, muscle aches and
pains, excessive sleep, malaise, fever, sore throat, tender lymph
nodes, impaired memory and/or mental concentration, insomnia, and
depression. Like patients with FMS, patients with CFS suffer from
disordered sleep, localized tenderness, and complaints of diffuse
pain and fatigue.
[0004] There are two widely used criteria for diagnosing CFS. The
criteria established by the U.S. Centers for Disease Control and
Prevention include medically unexplained fatigue of at least six
months duration that is of new onset, not a result of ongoing
exertion and not substantially alleviated by rest, and a
substantial reduction in previous levels of activity. In addition,
the diagnosis involves the determination of the presence of four or
more of the following symptoms--subjective memory impairment,
tender lymph nodes, muscle pain, joint pain, headache, unrefreshing
sleep, and postexertional malaise (>24 hours). Reid et al.,
2000, British Medical Journal 320: 292-296. The diagnostic criteria
from Oxford includes severe, disabling fatigue of at least six
months duration that affects both physical and mental functioning
and the fatigue being present for more than 50% of the time. In
addition, the diagnosis involves the determination of the presence
of other symptoms, particularly myalgia and sleep and mood
disturbance. Reid et al., 2000, British Medical Journal 320:
292-296.
[0005] Owing to their common symptomology, FMS and CFS are thought
to be related. However, they manifest different major symptoms.
Whereas pain is the major symptom reported by patients with FMS,
fatigue is the major symptom reported by patients with CFS. Given
their relatedness, these two indications have been treated with the
same medications. Some of the common medications currently employed
to treat CFS and/or FMS include, but are not limited to,
analgesics, hypnotics, immune suppressants, various other
prescribed medications, and an array of non-prescription
medications. Although a broad array of medications are used in FMS
and CFS patients, no single pharmacological agent or combination of
agents is effective in the treatment of either of these disorders.
Thus, due to the lack of effective treatment regimens for FMS
and/or CFS, there is a need to develop effective treatments.
[0006] Pain is associated with a variety of different underlying
illnesses or injuries. Pain may be either acute or chronic. Chronic
or intractable pain is often endured over many years or decades.
Patients suffering from chronic pain often develop emotional
problems which can lead to depression and in the worst case,
attempted suicide. Long lasting pain often occurs particularly in
joints, in muscles, connective tissue and in the back. In the
United States alone, chronic pain causes a loss of more than 250
million working days per year. A patient is considered to have
chronic pain when complaints thereof last longer than six months.
In the course of time, chronic pain may form an independent
clinical syndrome.
[0007] Most analgesic agents in use today are not always effective,
may produce serious side effects and can be addictive. Hence, there
is a demand for more active analgesic agents with diminished side
effects and toxicity, and which are non-addictive. The ideal
analgesic would reduce the awareness of pain, produce analgesia
over a wide range of pain types, act satisfactorily whether given
orally or parenterally, produce minimal or no side effects, and be
free from the tendency to produce tolerance and drug
dependence.
3. SUMMARY OF THE INVENTION
[0008] In one aspect, the invention provides a method of treating
fibromyalgia syndrome (FMS) and/or the symptoms associated
therewith in an animal subject, including a human. The method
generally involves administering to an animal subject suffering
from FMS an effective amount of a dual serotonin norepinephrine
reuptakeinhibitor ("SNRI") compound of a specific type, or a
pharmaceutically acceptable salt thereof. The SNRI compounds that
are useful to treat FMS and/or symptoms associated therewith are
characterized by a non-tricyclic structure and inhibit the reuptake
of norepinephrine to an equal or greater extent than they inhibit
the reuptake of serotonin (referred to hereinafter as
"NE.gtoreq.5-HT SNRI compounds"). In one embodiment of the
invention, the NE.gtoreq.5-HT SNRI compound administered inhibits
norepinephrine reuptake to a greater degree than it inhibits
serotonin reuptake (referred to hereinafter as a "NE>5-HT SNRI
compound"). One particular example of such a NE>5-HT SNRI
compound is milnacipran, or a pharmaceutically acceptable salt
thereof. In another embodiment, the NE.gtoreq.5-HT SNRI compound is
not administered adjunctively with phenylalanine, tyrosine and/or
tryptophan.
[0009] In another aspect, the invention provides a method of
treating pain in an animal subject, including a human. The method
generally involves administering to an animal subject suffering
from pain an effective amount of a NE.gtoreq.5-HT SNRI compound, or
a pharmaceutically acceptable salt thereof. In one embodiment, a
NE>5-HT SNRI compound is administered. One particular example of
a NE>5-HT SNRI compound is milnacipran or a pharmaceutically
acceptable salt thereof. In another embodiment, the NE.gtoreq.5-HT
SNRI compound is not administered adjunctively with phenylalanine,
tyrosine and/or tryptophan.
[0010] In still another aspect, the invention provides a method of
treating CFS and/or symptoms associated therewith. The method
generally involves administering to a patient suffering from CFS an
effective amount of a NE.gtoreq.5-HT SNRI compound, or a
pharmaceutically acceptable salt thereof. In one embodiment, a
NE>5-HT SNRI compound is administered. One particular example of
a NE>5-HT SNRI compound is milnacipran or a pharmaceutically
acceptable salt thereof. In another embodiment, the NE.gtoreq.5-HT
SNRI compound is not administered adjunctively with phenylalanine,
tyrosine and/or tryptophan.
[0011] In yet another aspect, the invention provides a kit
comprising a NE.gtoreq.5-HT SNRI compound packaged in association
with instructions teaching a method of using the compound according
to one or more of the above-described methods. The kit can contain
the NE.gtoreq.5-HT SNRI compound packaged in unit dosage form. In
one embodiment, a NE>5-HT compound can be included in the kit.
One particular example of a NE>5-HT SNRI compound is milnacipran
or a pharmaceutically acceptable salt thereof.
4. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
4.1 Abbreviations
[0012] CFS chronic fatigue syndrome [0013] FMS fibromyalgia
syndrome [0014] 5-HT serotonin [0015] NARIs norepinephrine specific
reuptake inhibitors [0016] NE norepinephrine [0017] NMDA N-methyl
D-aspartate [0018] NSAIDs non-steroidal anti-inflammatory drugs
[0019] SSRIs selective serotonin reuptake inhibitors [0020] TCAs
tricyclic antidepressants [0021] SNRIs dual serotonin
norepinephrine reuptake inhibitors
4.2 Definitions
[0022] The term "dual serotonin norepinephrine reuptake inhibitor
compound" or SNRI refers to the well-recognized class of
anti-depressant compounds that selectively inhibit reuptake of both
serotonin and norepinephrine. Common SNRI compounds include, but
are not limited to, venlafaxine, duloxetine, and milnacipran.
[0023] The terms "NE.gtoreq.5-HT SNRI" and "NE>5-HT SNRI" refer
to particular subclasses of SNRI compounds that are useful in the
methods and kits of the present invention, as will be described in
more detail herein.
4.3 Treatment of FMS, CFS and/or Pain
[0024] The present invention provides methods and kits for treating
FMS, CFS, and pain. A particular subclass of SNRI compounds is
useful for practicing the present invention. Compounds in this SNRI
subclass, referred to as "NE.gtoreq.5-HT SNRI compounds," inhibit
norepinephrine reuptake more than or equal to serotonin reuptake.
Moreover, the NE.gtoreq.5-HT compounds of the invention exclude
compounds that belong to the distinct class of antidepressant
compounds commonly referred to in the art as tricyclic
antidepressants or TCAs. In particular, compounds useful for
practicing the present invention inhibit norepinephrine reuptake
more than serotonin reuptake, referred to as "NE>5-HT SNRI
compounds."
[0025] Tricyclic antidepressants (TCAs) are a well-recognized class
of antidepressant compounds that are characterized by a
dibenz[b,e]azepine (structure I), dibenz[b,e]oxepine (structure
II), dibenz[a,d]cycloheptane (structure III) or
dibenz[a,d]cycloheptene (structure IV) tricyclic ring structure.
These various rings are depicted below:
##STR00001##
The TCAs are typically substituted at position 1 of the tricyclic
ring with alkylamines or alkylidenamines, and may include
additional substituents (typically on the benzo groups). Many
common TCAs, including imipramine, desipramine, clomipramine,
trimipramine, amitriptyline, nortriptyline, doxepin,
cyclobenzaprine and protriptline are characterized by the general
formula (V), below:
##STR00002##
[0026] wherein: [0027] X is O or C; [0028] Y is N or C; [0029]
R.sup.1 is H or Cl; [0030] R.sup.2 is selected from the group
consisting of --(CH.sub.2).sub.3N(CH.sub.3).sub.2,
--(CH.sub.2).sub.3NHCH.sub.3,
--CH.sub.2CH(CH.sub.3)CH.sub.2N(CH.sub.3).sub.2,
.dbd.CH(CH.sub.2)N(CH.sub.3).sub.2,
.dbd.CH(CH.sub.2).sub.2NHCH.sub.3 and --(CH.sub.2).sub.3NHCH.sub.3;
and [0031] the dotted line represents a single bond or a double
bond. The NE.gtoreq.5-HT SNRI compounds of the invention exclude
compounds classified as tricyclic antidepressants, and thus exclude
compounds characterized by the above-depicted fused tricyclic
nuclei of structures (I), (II), (III), and (IV).
[0032] As mentioned above, the NE.gtoreq.5-HT SNRI compounds useful
in the methods and kits of the invention include compounds that
inhibit norepinephrine reuptake to a greater extent than serotonin
reuptake, as well as compounds that inhibit the reuptake of these
two monoamines to an equivalent extent. In one embodiment of the
invention, the NE.gtoreq.5-HT SNRI compounds have a ratio of
inhibition of norepinephrine reuptake to serotonin reuptake
("NE:5-HT") in the range of about 1-100:1. In a particular
embodiment, the compounds are NE>5-HT SNRI compounds, i.e.,
compounds that inhibit norepinephrine reuptake to a greater extent
than serotonin reuptake. Such NE>5-HT SNRI compounds generally
have a NE:5-HT in the range of about 1.1-100:1. That is, such
NE>5-HT SNRI compounds are at least about 1.1 to about 100 times
more effective at inhibiting norepinephrine reuptake than serotonin
reuptake. NE>5-HT SNRI compounds having a NE:5-HT ratio in the
range of about 2:1 to about 10:1 may be particularly effective.
[0033] Various techniques are known in the art to determine the
NE:5-HT of a particular SNRI. In one embodiment, the ratio can be
calculated from IC.sub.50 data for NE and 5-HT reuptake inhibition.
For example, it has been reported that for milnacipran the
IC.sub.50 of norepinephrine reuptake is 100 nM, whereas the
IC.sub.50 serotonin reuptake inhibition is 200 nM. See Moret et
al., 1985, Neuropharmacology 24(12):1211-1219; Palmier et al.,
1989, Eur J Clin Pharmacol 37:235-238. Therefore, the NE:5-HT
reuptake inhibition ratio for milnacipran based on this data is
2:1. Of course, other IC values such as IC.sub.25, IC.sub.75, etc.
could be used, so long as the same IC value is being compared for
both norepinephrine and serotonin. The concentrations necessary to
achieve the desired degree of inhibition (i.e., IC value) can be
calculated using known techniques either in vivo or in vitro. See
Sanchez et al., 1999, Cellular and Molecular Neurobiology
19(4):467-489; Turcotte et al., 2001, Neuropsychopharmacology
24(5):511-521; Moret et al., 1985, Neuropharmacology
24(12):1211-1219; Moret et al., 1997, J. Neurochem. 69(2): 815-822;
Bel et al., 1999, Neuropsychopharmacology 21(6):745-754; and
Palmier et al., 1989, Eur J Clin Pharmacol 37:235-238.
[0034] The NE:5-HT of a particular SNRI also can be calculated
using equilibrium dissociation constants (K.sub.D's) for
norepinephrine and serotonin transporters as described in Tatsumi
et al., 1997, European Journal of Pharmacology 340:249-258. For
example, a NE>5-HT SNRI compound with a K.sub.D of 2 nM for the
norepinephrine transporter and a K.sub.D of 8 nM for the serotonin
transporter has an NE:5-HT of 4:1.
[0035] Yet another means for determining the NE:5-HT of a
particular SNRI involves measuring the affinity (K.sub.i) of the
SNRI for the norepinephrine and serotonin transporters as described
in Owens et al., 1997, JPET 283:1305-1322. For example, a
NE>5-HT SNRI compound with a K.sub.i of 1 nM for the
norepinephrine transporter and a K.sub.i of 20 nM for the serotonin
transporter has an NE:5-HT of 20:1.
[0036] A specific example of a NE.gtoreq.5-HT SNRI compound that
can be used to practice the present invention is milnacipran.
Additional NE.gtoreq.5-HT SNRI compounds that can be used to
practice the present invention include, by way of example and not
limitation, any of the aminocyclopropane derivatives disclosed in
the following references that inhibit norepinephrine reuptake to an
equivalent or greater extent than serotonin reuptake (i.e., that
have a NE:5-HT ratio that is .gtoreq.1:1): WO95/22521; U.S. Pat.
No. 5,621,142; Shuto et al., 1995, J. Med. Chem. 38:2964-2968;
Shuto et al., 1996, J. Med. Chem. 39:4844-4852; Shuto et al., 1998,
J. Med. Chem. 41:3507-3514; Shuto et al., 2001, Jpn. J. Pharmacol.
85:207-213; Noguchi et al., 1999, Synapse 31:87-96; and U.S. Pat.
No. 4,478,836. All of these references are hereby incorporated
herein by reference in their entireties.
[0037] In a specific embodiment of the invention, the NE>5-HT
SNRI compound is milnacipran. The chemical structure of
milnacipran,
cis-(.+-.)-2-(aminomethyl)-N,N-diethyl-1-phenyl-yclopropanecarboxamide,
is as follows:
##STR00003##
Milnacipran is also known in the art as F2207, TN-912, dalcipran,
midalcipran, and midalipran. The NE:5-HT of milnacipran is 2:1. See
Moret et al., 1985, Neuropharmacology 24(12):1211-1219; Palmier et
al., 1989, Eur J Clin Pharmacol 37:235-238. Milnacipran and methods
for its synthesis are described in U.S. Pat. No. 4,478,836, which
is hereby incorporated by reference in its entirety. Additional
information regarding milnacipran may be found in the Merck Index,
12.sup.th Edition, at entry 6281. Quite significantly, milnacipran
has been used as an antidepressant in approximately 400,000
patients, and is known to be non-toxic in humans. In clinical
trials at dosages of 100 mg/day or 200 mg/day, milnacipran was well
tolerated and usually produced no more adverse effects than placebo
(Spencer and Wilde, 1998, Drugs 56(3):405-427).
[0038] Those of skill in the art will recognize that NE.gtoreq.5-HT
SNRI compounds such as milnacipran may exhibit the phenomena of
tautomerism, conformational isomerism, geometric isomerism and/or
optical isomerism. It should be understood that the invention
encompasses any tautomeric, conformational isomeric, optical
isomeric and/or geometric isomeric forms of the NE.gtoreq.5-HT SNRI
compounds having one'or more of the utilities described herein, as
well as mixtures of these various different forms. For example, as
is clear from the above structural diagram, milnacipran is
optically active. It has been reported in the literature that the
dextrogyral enantiomer of milnacipran is about twice as active in
inhibiting norepinephrine and serotonin reuptake than the racemic
mixture, and that the levrogyral enantiomer is much less potent
(see, e.g., Spencer and Wilde, 1998, supra; Viazzo et al., 1996,
Tetrahedron Lett. 37(26):4519-4522; Deprez et al., 1998, Eur. J.
Drug Metab. Pharmacokinet. 23(2):166-171). Accordingly, milnacipran
may be administered in entantiomerically pure form (e.g., the pure
dextrogyral enantiomer) or as a mixture of dextogyral and
levrogyral enantiomers, such as a racemic mixture. Unless
specifically noted otherwise, the term "milancipran" as used herein
refers to both enantiomerically pure forms of milnacipran as well
as to mixtures of milnacipran enantiomers. Methods for separating
and isolating the dextro- and levrogyral enantiomers of milnacipran
and other NE.gtoreq.5-HT SNRI compounds are well-known (see, e.g.,
Grard et al., 2000, Electrophoresis 2000 21:3028-3034).
[0039] It will also be appreciated that in many instances the
NE.gtoreq.5-HT SNRI compounds may metabolize to produce active
NE.gtoreq.5-HT SNRI compounds. The use of active metabolites is
also within the scope of the present invention.
[0040] It has been reported that milnacipran and its derivatives
have antagonistic properties at the NMDA receptor. See Shuto et
al., 1995, J. Med. Chem. 38:2964-2968; Shuto et al., 1996, J. Med.
Chem. 39:4844-4852; Shuto et al., 1998, J. Med. Chem. 41:3507-3514;
and Shuto et al., 2001, Jpn. J. Pharmacol. 85:207-213. As a
consequence, one particularly useful embodiment of the invention
includes NE.gtoreq.5-HT SNRI compounds that also have NMDA
antagonistic properties. The NE.gtoreq.5-HT SNRI compounds with
NMDA receptor antagonistic properties can have IC.sub.50 values
from about 1 nM-100 .mu.M. For example, milnacipran has been
reported to have an IC.sub.50 value of about 6.3 .mu.M. The NMDA
receptor antagonistic properties of milnacipran and its derivatives
are described in Shuto et al., 1995, J. Med. Chem., 38:2964-2968;
Shuto et al., 1996, J. Med. Chem. 39:4844-4852; Shuto et al., 1998,
J. Med. Chem. 41:3507-3514; and Shuto et al., 2001, Jpn. J.
Pharmacol. 85:207-213. Methods for determining the antagonism and
affinity for antagonism are disclosed in Shuto et al., 1995, J.
Med. Chem. 38:2964-2968; Shuto et al., 1996, J. Med. Chem.
39:4844-4852; Shuto et al., 1998, J. Med. Chem. 41:3507-3514;
Noguchi et al., 1999, Synapse 31:87-96; and Shuto et al., 2001,
Jpn. J. Pharmacol. 85:207-213. Aminocyclopropane derivatives
disclosed in WO95/22521; U.S. Pat. No. 5,621,142; Shuto et al.,
1995, J. Med. Chem. 38:2964-2968; Shuto et al., 1996, J. Med. Chem.
39:4844-4852; Shuto et al., 1998, J. Med. Chem. 41:3507-3514;
Noguchi et at, 1999, Synapse 31:87-96; and Shuto et al., 2001, Jpn.
J. Pharmacol. 85:207-213 that inhibit NE reuptake equal to or
greater than 5-HT reuptake and have NMDA antagonistic properties
can be used to practice the present invention. These references are
hereby incorporated by reference in their entirety.
[0041] It has recently been reported that compounds that inhibit
reuptake of both NE and 5-HT, such as venlafaxine, duloxetine,
milnacipran, and certain TCAs, are effective for the treatment of
pain, CFS and FMS, among other maladies, when administered in
combination with neurotransmitter precursors such as phenylalanine,
tyrosine and/or tryptophan. See WO 01/26623. For example, according
to one study reported in WO 01/26623, a patient experiencing, inter
alfa, fatigue and fibromyalgia, was administered many types of
drugs, including many types of non-steroidal anti-inflammatories,
both tricyclic and serotonin reuptake inhibiting and noradrenalin
reuptake inhibiting antidepressants, and even steroids, without
effect. When given a combination of lofepramine (70 mg. bd) and
L-phenylalanine (500 mg. bd), the patient experienced a
considerable improvement in fatigue and fibromyalgia, which
persisted for more than six months. Thus, a compound that inhibits
reuptake of both NE and 5-HT was effective only when administered
in combination with a neurotransmitter precursor.
[0042] Quite surprisingly, the present inventors have discovered
that the NE.gtoreq.5-HT SNRI subclass of SNRI compounds are
effective in treating CFS, FMS and pain when administered alone (or
in combination with other compounds that are not neurotransmitter
precursors such as phenylalanine, tyrosine and/or tryptophan, as
will be discussed in more detail, below). Thus, in one embodiment
of the invention, the NE.gtoreq.5-HT SNRI compound is administered
alone, or in combination with a compound other than a
neurotransmitter precursor such as phenylalanine, tyrosine and/or
tryptophan.
[0043] The NE.gtoreq.5-HT SNRI compounds, such as, for example,
milnacipran, can be administered adjunctively with other active
compounds such as antidepressants, analgesics, muscle relaxants,
anorectics, stimulants, antiepileptic drugs, and
sedative/hypnotics. Specific examples of compounds that can be
adjunctively administered with the NE.gtoreq.5-HT SNRI compounds
include, but are not limited to, neurontin, pregabalin,
pramipexole, 1-DOPA, amphetamine, tizanidine, clonidine, tramadol,
morphine, tricyclic antidepressants, codeine, cambamazepine,
sibutramine, amphetamine, valium, trazodone and combinations
thereof. Typically for FMS patients the NE.gtoreq.5-HT SNRI
compounds may be adjunctively administered with antidepressants,
anorectics, analgesics, antiepileptic drugs, muscle relaxants, and
sedative/hypnotics. For CFS patients, the NE.gtoreq.5-HT SNRI
compounds may be adjunctively administered antidepressants,
anorectics, stimulants, and sedative/hypnotics. For patients
suffering from pain the NE.gtoreq.5-HT SNRI compounds may be
adjunctively administered with antidepressants, analgesics,
antiepileptic drugs. By adjunctive administration is meant
simultaneous administration of the compounds, in the same dosage
form, simultaneous administration in separate dosage forms, and
separate administration of the compounds. For example, milnacipran
can be simultaneously administered with valium, wherein both
milnacipran and valium are formulated together in the same tablet.
Alternatively, inilnacipran could be simultaneously administered
with valium, wherein both the milnacipran and valium are present in
two separate tablets. In another alternative, milnacipran could be
administered first followed by the administration of valium, or
vice versa.
[0044] The NE.gtoreq.5-HT SNRI compounds can be administered
therapeutically to achieve a therapeutic benefit or
prophylactically to achieve a prophylactic benefit. By therapeutic
benefit is meant eradication or amelioration of the underlying
disorder being treated, e.g., eradication or amelioration of the
underlying FMS, CFS or pain disorder, and/or eradication or
amelioration of one or more of the physiological symptoms
associated with the underlying disorder such that the patient
reports an improvement in feeling or condition, notwithstanding
that the patient may still be afflicted with the underlying
disorder. For example, administration of milnacipran to a patient
suffering from FMS provides therapeutic benefit not only when the
underlying FMS indication is eradicated or ameliorated, but also
when the patient reports decreased fatigue, improvements in sleep
patterns, and/or a decrease in the severity or duration of
pain.
[0045] Although depression is often comorbid in patients suffering
from FMS and CFS, and could therefore be characterized as a symptom
associated with these disorders, it is well-recognized in the art
that NE.gtoreq.5-HT SNRI compounds such as milnacipran are useful
in the treatment of depression. Accordingly, while successful
treatment regimens of the invention contemplate providing an
improvement in at least one symptom associated with FMS or CFS,
treatment regimens that cause an improvement only in depression are
considered ineffective for purposes of the present invention. While
improvements in associated psychological symptoms such as
depression may be reported, for purposes of the present invention,
an improvement in the underlying disorder and/or in at least one of
the physiological symptoms associated with the disorder must be
reported. Thus, the present invention does not contemplate the
treatment of depression alone.
[0046] For therapeutic administration, the NE.gtoreq.5-HT SNRI
compound typically will be administered to a patient already
diagnosed with the particular indication being treated.
[0047] For prophylactic administration, the NE.gtoreq.5-HT SNRI
compound may be administered to a patient at risk of developing
FMS, CFS, or pain or to a patient reporting one or more of the
physiological symptoms of FMS or CFS, even though a diagnosis of
FMS or CFS may not have yet been made. Alternatively, prophylactic
administration may be applied to avoid the onset of the
physiological symptoms of the underlying disorder, particularly if
the symptom manifests cyclically. In this latter embodiment, the
therapy is prophylactic with respect to the associated
physiological symptoms instead of the underlying indication. For
example, the NE.gtoreq.-HT SNRI compound could be prophylactically
administered prior to bedtime to avoid the sleep disturbances
associated with FMS or CFS. Alternatively, the NE.gtoreq.5-HT SNRI
compound could be administered prior to recurrence of pain, or
prior to onset of fatigue.
[0048] While the invention has been described so far with respect
to NE.gtoreq.5-HT SNRI compounds, the present invention can also be
practiced with norepinephrine specific reuptake inhibitors (NARIs).
NARIs are a well-recognized class of compounds that specifically
inhibit the reuptake of only norepinephrine. An example of a
compound that is classified as a NARI is reboxetine.
4.4 Formulation and Routes of Administration
[0049] The NE.gtoreq.5-HT SNRI compounds useful in the present
invention, or pharmaceutically acceptable salts thereof, can be
delivered to a patient using a wide variety of routes or modes of
administration. Suitable routes of administration include, but are
not limited to, inhalation, transdermal, oral, rectal,
transmucosal, intestinal and parenteral administration, including
intramuscular, subcutaneous and intravenous injections.
[0050] The term "pharmaceutically acceptable salt" means those
salts which retain the biological effectiveness and properties of
the compounds used in the present invention, and which are not
biologically or otherwise undesirable. Such salts include salts
with inorganic or organic acids, such as hydrochloric acid,
hydrobromic acid, phosphoric acid, nitric acid, sulfuric acid,
methanesulfonic acid, p-toluenesulfonic acid, acetic acid, fumaric
acid, succinic acid, lactic acid, mandelic acid, malic acid, citric
acid, tartaric acid or maleic acid. In addition, if the compounds
used in the present invention contain a carboxy group or other
acidic group, it may be converted into a pharmaceutically
acceptable addition salt with inorganic or organic bases. Examples
of suitable bases include sodium hydroxide, potassium hydroxide,
ammonia, cyclohexylamine, dicyclohexyl-amine, ethanolamine,
diethanolamine and triethanolamine.
[0051] The compounds, or pharmaceutically acceptable salts thereof,
may be administered singly, in combination with other
NE.gtoreq.5-HT SNRI compounds, and/or in cocktails combined with
other therapeutic agents. Of course, the choice of therapeutic
agents that can be co-administered with the compounds of the
invention will depend, in part, on the condition being treated.
[0052] The active NE.gtoreq.5-HT SNRI compounds (or
pharmaceutically acceptable salts thereof) may be administered per
se or in the form of a pharmaceutical composition wherein the
active compound(s) is in admixture or mixture with one or more
pharmaceutically acceptable carriers, excipients or diluents.
Pharmaceutical compositions for use in accordance with the present
invention may be formulated in conventional manner using one or
more physiologically acceptable carriers comprising excipients and
auxiliaries which facilitate processing of the active compounds
into preparations which can be used pharmaceutically. Proper
formulation is dependent upon the route of administration
chosen.
[0053] For injection, the NE.gtoreq.5-HT SNRI compounds may be
formulated in aqueous solutions, preferably in physiologically
compatible buffers such as Hanks's solution, Ringer's solution, or.
physiological saline buffer. For transmucosal administration,
penetrants appropriate to the barrier to be permeated are used in
the formulation. Such penetrants are generally known in the
art.
[0054] For oral administration, the compounds can be formulated
readily by combining the active compound(s) with pharmaceutically
acceptable carriers well known in the art. Such carriers enable the
compounds of the invention to be formulated as tablets, pills,
dragees, capsules, liquids, gels, syrups, slurries, suspensions and
the like, for oral ingestion by a patient to be treated.
Pharmaceutical preparations for oral use can be obtained as a solid
excipient, optionally grinding a resulting mixture, and processing
the mixture of granules, after adding suitable auxiliaries, if
desired, to obtain tablets or dragee cores. Suitable excipients
are, in particular, fillers such as sugars, including lactose,
sucrose, mannitol, or sorbitol; cellulose preparations such as, for
example, maize starch, wheat starch, rice starch, potato starch,
gelatin, gum tragacanth, methyl cellulose,
hydroxypropylmethyl-cellulose, sodium carboxymethylcellulose,
and/or polyvinylpyrrolidone (PVP). If desired, disintegrating
agents may be added, such as the cross-linked polyvinyl
pyrrolidone, agar, or alginic acid or a salt thereof such as sodium
alginate.
[0055] Dragee cores can be provided with suitable coatings. For
this purpose, concentrated sugar solutions may be used, which may
optionally contain gum arabic, talc, polyvinyl pyrrolidone,
carbopol gel, polyethylene glycol, and/or titanium dioxide, lacquer
solutions, and suitable organic solvents or solvent mixtures.
Dyestuffs or pigments may be added to the tablets or dragee
coatings for identification or to characterize different
combinations of active compound doses.
[0056] For administration orally, the compounds may be formulated
as a sustained release preparation. Numerous techniques for
formulating sustained release preparations are described in the
following references--U.S. Pat. Nos. 4,891,223; 6,004,582;
5,397,574; 5,419,917; 5,458,005; 5,458,887; 5,458,888; 5,472,708;
6,106,862; 6,103,263; 6,099,862; 6,099,859; 6,096,340; 6,077,541;
5,916,595; 5,837,379; 5,834,023; 5,885,616; 5,456,921; 5,603,956;
5,512,297; 5,399,362; 5,399,359; 5,399,358; 5,725,883; 5,773,025;
6,110,498; 5,952,004; 5,912,013; 5,897,876; 5,824,638; 5,464,633;
5,422,123; and 4,839,177; and WO 98/47491. Specifically, sustained
release formulations of milnacipran are described in WO 98/08495.
These references are hereby incorporated herein by reference in
their entireties.
[0057] Pharmaceutical preparations which can be used orally include
push-fit capsules made of gelatin, as well as soft, sealed capsules
made of gelatin and a plasticizer, such as glycerol or sorbitol.
The push-fit capsules can contain the active ingredients in
admixture with filler such as lactose, binders such as starches,
and/or lubricants such as talc or magnesium stearate and,
optionally, stabilizers. In soft capsules, the active compounds may
be dissolved or suspended in suitable liquids, such as fatty oils,
liquid paraffin, or liquid polyethylene glycols. In addition,
stabilizers may be added. All formulations for oral administration
should be in dosages suitable for such administration.
[0058] For buccal administration, the compositions may take the
form of tablets or lozenges formulated in conventional manner.
[0059] For administration by inhalation, the active compound(s) may
be conveniently delivered in the form of an aerosol spray
presentation from pressurized packs or a nebulizer, with the use of
a suitable propellant, e.g., dichlorodifluoromethane,
trichlorofluoromethane, dichlorotetrafluoroethane, carbon dioxide
or other suitable gas. In the case of a pressurized aerosol the
dosage unit may be determined by providing a valve to deliver a
metered amount. Capsules and cartridges of e.g. gelatin for use in
an inhaler or insufflator may be formulated containing a powder mix
of the compound and a suitable powder base such as lactose or
starch.
[0060] The compounds may be formulated for parenteral
administration by injection, e.g., by bolus injection or continuous
infusion. Formulations for injection may be presented in unit
dosage form, e.g., in ampoules or in multi-dose containers, with an
added preservative. The compositions may take such forms as
suspensions, solutions or emulsions in oily or aqueous vehicles,
and may contain formulatory agents such as suspending, stabilizing
and/or dispersing agents.
[0061] Pharmaceutical formulations for parenteral administration
include aqueous solutions of the active compounds in water-soluble
form. Additionally, suspensions of the active compounds may be
prepared as appropriate oily injection suspensions. Suitable
lipophilic solvents or vehicles include fatty oils such as sesame
oil, or synthetic fatty acid esters, such as ethyl oleate or
triglycerides, or liposomes. Aqueous injection suspensions may
contain substances which increase the viscosity of the suspension,
such as sodium carboxymethyl cellulose, sorbitol, or dextran.
Optionally, the suspension may also contain suitable stabilizers or
agents which increase the solubility of the compounds to allow for
the preparation of highly concentrated solutions.
[0062] Alternatively, the active compound(s) may be in powder form
for constitution with a suitable vehicle, e.g., sterile
pyrogen-free water, before use.
[0063] The compounds may also be formulated in rectal compositions
such as suppositories or retention enemas, e.g., containing
conventional suppository bases such as cocoa butter or other
glycerides.
[0064] In addition to the formulations described previously, the
compounds may also be formulated as a depot preparation. Such long
acting formulations may be administered by implantation or
transcutaneous delivery (for example subcutaneously or
intramuscularly), intramuscular injection or a transdermal patch.
Thus, for example, the compounds may be formulated with suitable
polymeric or hydrophobic materials (for example as an emulsion in
an acceptable oil) or ion exchange resins, or as sparingly soluble
derivatives, for example, as a sparingly soluble salt.
[0065] The pharmaceutical compositions also may comprise suitable
solid or gel phase carriers or excipients. Examples of such
carriers or excipients include but are not limited to calcium
carbonate, calcium phosphate, various sugars, starches, cellulose
derivatives, gelatin, and polymers such as polyethylene
glycols.
4.5 Effective Dosages
[0066] Pharmaceutical compositions suitable for use in the present
invention include compositions wherein the active ingredient is
contained in a therapeutically or prophylactically effective
amount, i.e., in an amount effective to achieve therapeutic or
prophylactic benefit, as previously discussed. Of course, the
actual amount effective for a particular application will depend,
inter alia, on the condition being treated and the route of
administration. Determination of an effective amount is well within
the capabilities of those skilled in the art, especially in light
of the disclosure herein.
[0067] Therapeutically effective amounts for use in humans can be
determined from animal models. For example, a dose for humans can
be formulated to achieve circulating concentration that has been
found to be effective in animals. Useful animal models of pain are
well known in the art. Models of neuropathic pain are described in
Zeltser et al., 2000, Pain 89:19-24; Bennett et al., 1988, Pain
33:87-107; Seltzer et al., 1990, Pain 43:205-218; Kim et al., 1992,
Pain 50:355-363; and Decosterd et al., 2000, Pain 87:149-158. An
animal model of inflammatory pain using complete Freund's adjuvant
is described in Jasmin et al., 1998, Pain 75: 367-382. The
stress-induced hyperalgesia model described in Quintero et al.,
2000, Pharmacology, Biochemistry and Behavior 67:449-458 may be
used as an animal model of FMS and CFS.
[0068] Effective amounts for use in humans can be also be
determined from human data for the NE.gtoreq.5-HT SNRI compounds
used to treat depression. The amount administered can be the same
amount administered to treat depression or can be an amount lower
than the amount administered to treat depression. For example, the
amount of milnacipran administered to treat depression is in the
range of about 50 mg-400 mg/day. Thus, either 50 mg-400 mg/day or a
lower dose can be administered for practicing the present
invention.
[0069] Patient doses for oral administration of the NE.gtoreq.5-HT
SNRI compound typically range from about 1 .mu.g-1 gm/day. For
example, for the treatment of FMS, CFS, or pain with milnacipran
the dosage range is typically from 25 mg-400 mg/day, more typically
from 100 mg-250 mg/day. The dosage may be administered once per day
or several or multiple times per day. The amount of the
NE.gtoreq.5-HT SNRI compound administered to practice methods of
the present invention will of course, be dependent on the subject
being treated, the severity of the affliction, the manner of
administration and the judgment of the prescribing physician. The
dose used to practice the invention can produce the desired
therapeutic or prophylactic effects, without producing serious side
effects.
5. EXAMPLES
5.1 Example 1
Assessment of the Analgesic Properties of Milnacipran in a Rat Pain
Model
[0070] The rats used in this study are divided into two groups. One
group of rats receive a spinal ligation as described in Kim et al.,
1992, Pain 50(3):355-63 and the other group of rats receive a sham
surgery. Each group of rats is further divided into 5 subgroups.
Each subgroup receives subcutaneous injection of the vehicle or one
of the 4 test doses of milnacipran (5, 10, 25, and 50 mg/kg). The
vehicle or milnacipran are administered at a pre-determined time
point following the surgeries. Allodynia and thermal hyperalgesia
are respectively measured with Von Frey filaments and tail- or
paw-flick with a radiant heat source. The allodynia and thermal
hyperalgesia measurements are performed at the following time
points--prior to surgery, following surgery but prior to the
administration of vehicle or milnacipran, and following surgery
after the administration of vehicle or milnacipran. The allodynia
and thermal hyperalgesia measurements will provide information on
the ability of milnacipran to block the development of mechanical
allodynia and thermal hyperalgesia.
5.2 Example 2
Assessment of the Efficacy of Milnacipran in an FMS Animal
Model
[0071] This study is performed on rats or mice that have undergone
stress-induced hyperalgesia as described in Quintero et al., 2000,
Pharmacology, Biochemistry and Behavior 67:449-458. The study
consists of 3 groups: placebo, milnacipran subcutaneous
pretreatment, and milnacipran treatment. The milnacipran groups are
further divided to 4 subgroups and each subgroup is administered 5,
10, 25, or 50 mg/kg of milnacipran. In the milnacipran subcutaneous
pretreatment group, the milnacipran is administered prior to the
inducement of the stress-induced hyperalgesia. In the milnacipran
treatment group, the milnacipran is administered following the
inducement of the stress-induced hyperalgesia. Allodynia and
thermal hyperalgesia are respectively measured with Von Frey
filaments and tail- or paw-flick with a radiant heat source. The
allodynia and thermal hyperalgesia measurements are performed at
the following time points--prior to both the inducement of
stress-induced hyperalgesia and the administration of the
milnacipran, prior to the inducement of stress-induced hyperalgesia
but following the administration of the milnacipran, following the
inducement of stress-induced hyperalgesia but prior to
administration of the milnacipran, following both the inducement of
stress-induced hyperalgesia and the administration of the
milnacipran. The allodynia and thermal hyperalgesia measurements
provide information on whether pretreatment or treatment with
milnacipran will be effective in the treatment of stress-induced
thermal and mechanical hyperalgesia.
5.3 Example 3
Assessment of the Efficacy of Milnacipran in FMS Patients
[0072] Approximately 40 subjects are studied for a total of 6
weeks, after being weaned from their previous analgesic or
antidepressant medications.
[0073] The inclusion criteria for this study is as follows: [0074]
1. Patients meet the 1990 American College of Rheumatology criteria
for fibromyalgia syndrome. [0075] 2. Male or female between the
ages of 18 and 70 years. Females are either postmenopausal (no
menses for at least 1 year) or status-post oophorectomy (bilateral)
or have a negative pregnancy test and be using an accepted method
of contraception. [0076] 3. Patients have a Gracely intensity pain
scale recording (weekly recall) of at least 10 or more on a 20
point scale at baseline. [0077] 4. Patients may use
non-prescription doses of NSAIDs, aspirin and acetaminophen on a
PRN basis for acute pain unrelated to their underlying
fibromyalgia.
[0078] The patients are divided into 2 groups. The first group is
administered 100 mg of milnacipran in a single-dose in the morning,
while the second group is administered 50 mg twice a day (i.e.,
upon awakening and prior to going to sleep). Each patient is then
followed for 6 weeks, with visits every two weeks, as follows:
##STR00004##
[0079] As indicated above, global patient (Pt) and physician (MD)
assessments are taken at the beginning and end of the trial. In
addition, a total of 4 sets of pain and sleep measures are also
performed at 2-week intervals. The pain measure consists of the
patient's recall of overall pain over the previous 2-week period as
indicated by a 10 cm visual analog scale. The sleep instrument
consists of 4 questions taken from the Jenkin's sleep
questionnaire. It is expected that milnacipran will produce an
improvement in a majority of the patients.
5.4 Example 4
Assessment of the Efficacy of Milnacipran in Patients with Painful
Diabetic Neuropathy
[0080] 20 patients with painful diabetic neuropathy (DN) are
studied in a double-blind cross-over study. The inclusion criteria
for the study are--age of between 18 and 85 years, daily pain of at
least "moderate intensity" on the Gracely scale for greater than
three months that was present more than 50% of the day, and
adequate communication ability demonstrated during a telephone
conversation and by completion of a pain diary. Additional
inclusion criteria are a diagnosis of diabetes, and distal,
symmetrical diabetic neuropathy as assessed by either an
unequivocal decrease in pinprick, temperature, or vibration sense
in both feet or ankles or decreased or absent ankle jerk reflexes.
Exclusion criteria are the presence of another more painful
condition, difficulty with ambulation, any unstable disease
process, a history of significant substance abuse or alcoholism,
liver or kidney disease, or concurrent use of a monoamine oxidase
inhibitor.
[0081] Milnacipran is compared to placebo in a randomized,
double-blind, two-period, crossover study. After discontinuing
other medication for pain for two weeks, patients enter a one-week
baseline period, followed by two six-week drug treatment periods,
separated and concluded by a one-week washout period. The
treatments, given in random order, are milnacipran titrated up to
maximum-tolerated dose or placebo. A nurse calls the patients every
three days to titrate medication dosage and to assess pain, side
effects, and study compliance. During the first four weeks of each
period (titration phase) the medication is increased by 25 mg/day
every three days unless the patient reports complete pain relief,
side effects that interfere with daily activities, or unless the
maximum dose of 200 mg daily is reached. During weeks 5 and 6
(maintenance phase), the highest well-tolerated dose is maintained
at a constant level.
[0082] Prior to randomization, a general physical exam and
laboratory tests (complete blood count, liver function tests, blood
glucose, hemoglobin Alc, blood urea nitrogen, creatinine,
electrolytes and urinalysis) is obtained. Diabetics are examined to
assure they had adequate blood sugar control before and during the
trial. They are instructed to perform daily blood sugar monitoring
using a fingerstick and a home glucometer. In addition, a
neurologic examination is performed at baseline to identify any
area of increased pain to pinprick (hyperalgesia), decreased
sensation to pinprick, or pain with stimulation by cotton gauze
(allodynia); these studies are conducted every 2 weeks during the
trial. In addition, patients record their pain intensity in a diary
3 times daily using the Gracely scale. It is expected that
milnacipran will produce an improvement in the majority of
patients, as measured by both physician neurological exam and
patient diary.
[0083] Each of the patent applications, patents, publications, and
other published documents mentioned or referred to in this
specification is herein incorporated by reference in its entirety,
to the same extent as if each individual patent application,
patent, publication, and other published document was specifically
and individually indicated to be incorporated by reference.
[0084] While the present invention has been described with
reference to the specific embodiments thereof, it should be
understood by those skilled in the art that various changes may be
made and equivalents may be substituted without departing from the
true spirit and scope of the invention. In addition, many
modifications may be made to adapt a particular situation,
material, composition of matter, process, process step or steps, to
the objective, spirit and scope of the present invention. All such
modifications are intended to be within the scope of the claims
appended hereto.
* * * * *