Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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METHOD AND PHARMACEUTICAL COMPOSITION FOR
REGULATING LIPID CONCENTRATION
BACKGROUND OF THE INVENTION
The treatment of patients with or at risk of
developing ischemic syndromes with doses of an HMG-CoA
reductase inhibitor to lower total and LDL cholesterol
is known. This is done in order to restore endogenous
vascular endothelium-dependent activities including,
but not limited to vasodilatory responses modulating
vascular tone and blood flow, antiadherent properties
of the blood vessel wall, and anticoagulation of
platelets (International Publication Number
WO 95/13063).
There is evidence from animal models that
compounds which inhibit the enzyme, acyl-coenzyme
A:cholesterol acyltransferase (ACAT) will be effective
anti-atherosclerotic agents,(Curr. Med. h r",
1994;1:204-225). It is well-established that when the
majority of cholesterol in plasma is carried on
apolipoprotein B-containing lipoproteins, such as low-
density lipoproteins (LDL-C) and very-low-density
lipoproteins (VLDL-C), the risk of coronary artery
disease in man is increased (Circulation, 1990;81:1721-
1733). Conversely, high levels of cholesterol carried
in high-density lipoproteins (HDL-C) is protective
against coronary artery disease (Am. J. Med.,
1977;62:707-714). Thus, a drug which reduces the
levels of atherogenic LDL-C and VLDL-C and elevates
levels of protective HDL-C will produce a less
atherogenic lipoprotein profile and thus a beneficial
effect on atherosclerotic disease and its
i
complications. This beneficial effect was demonstrated
in man in the Helsinki Heart Study with the lipid
regulator gemfibrozil which decreased LDL-C, increased
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HDL-C, and reduced the incidence of coronary artery
disease (N. Engl. J. Med., 1987;317:1237-1245).
SUMMARY OF THE INVENTION ,
We have now shown that a combination of ACAT
inhibitor and HMG-CoA reductase inhibitor when
administered in a chow/fat diet results in a greater
reduction in apo B-containing liproprotein than either
alone and that a normalization of the plasma
lipoprotein profile can be achieved. This means the
combination treatment results in plasma lipoprotein
profile associated with a decreased risk of coronary
artery disease.
We have also shown that a combination of ACAT
inhibitors and HMG-CoA reductase inhibitors reduces the
cholesteryl esters (CE) enrichment of pre-existing
atherosclerotic lesions to the same extent as the
HMG-CoA reductase inhibitor alone but that the
histologic character of the atherosclerotic lesions is
less complicated. This means that the lesions are less
prone to induce myocardial infarction.
DETAILED DESCRIPTION OF THE INVENTION
The novel method of treatment of this invention
and the novel pharmaceutical compositions comprise the
administration to a patient at risk of developing
atherosclerosis or a patient in whom the disease has
been diagnosed with an ACAT inhibitor and HMG-CoA
reductase inhibitor which will restore endogenous
vascular endothelium-dependent activities including
improving the normal dilation capacity of the
endothelium. This method may be used to induce
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vasodilation to modulate vascular tone and blood flow.
Other improvements in vascular endothelium-dependent
activities include decreasing the adherent properties
of the blood vessel walls and decreasing the
coagulation of platelets. Suitable subjects for the
method of the present invention include those
individuals who currently exhibit symptoms of
atherosclerosis and those who are at risk of developing
various acute ischemic syndromes including individuals
with high blood pressure, diabetes, or hyperlipidemia,
and individuals who smoke.
The various acute ischemic syndromes that may be
treated by the method of the present invention include:
angina pectoris, coronary artery disease (CAD),
hypertension, cerebrovascular accidents, transient
ischemic attacks, chronic,obstructive pulmonary
disease, chronic hypoxic lung disease, pulmonary
hypertension, renal hypertension, chronic renal
disease, microvascular complications of diabetes, and
vaso-occlusive complications of sickle cell anemia.
An HMG-CoA reductase inhibitor for use in the
novel method may be selected from atorvastatin,
lovastatin, simvastatin, pravastatin, fluvastatin, and
rivastatin; preferably atorvastatin, lovastatin, or
simvastatin; most preferably atorvastatin.
HMG-CoA reductase inhibitors are known to function
as antihypercholesterolemic agents. They reduce
hepatic cholesterol biosynthesis by inhibiting the
enzyme HMG-CoA reductase which catalyzes the early,
rate-limiting step in the biosynthesis of cholesterol,
the conversion of hydroxymethylglutarate to mevalonate.
Known HMG-CoA reductase inhibitors include atorvastatin
MEVACOR~ (lovastatin), ZOCOR~ (simvastatin), PRAVACHOL~
(pravastatin), LESCOL~ (fluvastatin), and rivastatin.
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H3C\ / CH3
O ;H ;H O
\ NHC iCH~ ~CH~ iC~
~ CH2 CH2 O
Ca 2+ w
Atorvastatin
H H C ///~ O ,
'H
3 H3C CH3~ H ,.H CH
3
/ /
H3C
Lovastatin Simvastatin
OH
Na00C
2 0 O HO
~~ H
O
H3C~i H .H
CH3 CH3
C02 Na+
/ /
HO
Pravastatin
Fluvastatin
Na+
F
~H3
H~
r
__
3 5 Rivastatin
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The doses of HMG-CoA reductase inhibitor
contemplated for use in this invention are about 5 to
80 mg per day, preferably given in single or divided
doses.
Preferably, the patient is placed on a prudent
r
lipid-lowering diet during the treatment with the
HMG-CoA reductase inhibitors.
Lipid lowering therapy with HMG-CoA reductase
inhibitors normalizes vascular function in patients
with hypercholesterolemia and/or coronary artery
disease without the requirement for significant
regression of the atherosclerotic lesions. The
coronary microcirculation, which demonstrates
significantly impaired endothelium dependent dilatory
responses in the presence of hypercholesterolemia and
atherosclerotic disease, but is usually free of
atheroma, is likely to show marked improvement
demonstrating the ability of lipid lowering therapy to
halt the progression and/or promote regression of
atherosclerosis in epicardial arteries in humans.
Atorvastatin is disclosed in United States Patent
Number 5,273,995. Related compounds are disclosed in
United States Patent Number 4,681,893.
Lovastatin and related compounds are disclosed
in United States Patent Number 4,231,938; simvastatin
and related compounds are disclosed in United States
Patent Number 4,450,171 and United States Patent
Number 4,346,227; pravastatin and related compounds are
disclosed in United States Patent Number 4,346,227 and
fluvastatin and related compounds are disclosed in
United States Patent Number 4,739,073; rivastatin and
related compounds are disclosed in United States
Patents Numbers 5,177,080 and 5,006,530.
Compounds which effectively inhibit the enzyme,
acyl-coenzyme A:cholesterol acyltransferase (ACAT)
prevent the intestinal absorption of dietary
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cholesterol into the blood stream or the reabsorption
of cholesterol which has been previously released into
the intestine through the body's own regulatory action.
The ACAT inhibiting compounds provide treatment of
hypercholesterolemia and atherosclerosis. Such
i
compounds include, for example, a compound of Formula I
O O
~.0 R1-X- ii -~-C-Y-R' 1
O R
or a pharmaceutically acceptable salt thereof wherein:
X and Y are selected from oxygen, sulfur and (CR'R")n,
wherein n is an integer of from 1 to 4 and R' and
R" are each independently hydrogen, alkyl, alkoxy,
halogen, hydroxy, acyloxy, cycloalkyl, phenyl
optionally substituted or R' and R" together form
a spirocycloalkyl or a carbonyl;
with the proviso at least one of X and Y is
(CR'R")n and with the further proviso when X and Y
are both (CR'R")n and R' and R" are hydrogen and n
is one, R1 and R2 are aryl;
R is hydrogen, a straight or branched alkyl of from
1 to 8 carbon atoms or benzyl;
R1 and R2 are each independently selected from
(a) phenyl or phenoxy each of which is
unsubstituted or is substituted with 1 to
5 substituents selected from
phenyl,
an alkyl group having from 1 to 6 carbon atoms and
which is straight or branched,
an alkoxy group having from 1 to 6 carbon atoms
and which is straight or branched;
phenoxy,
hydroxy,
fluorine,
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chlorine,
bromine,
nitro,
trifluoromethyl,
-COON,
-COOalkyl wherein alkyl has from 1 to 4 carbon
atoms and is straight or branched,
-(CH2)pNR3R4 wherein p is zero or one, and each of
R3 and R4 is selected from hydrogen or a
straight or branched alkyl group having 1 to
4 carbon atoms;
(b) 1- or 2-naphthyl unsubstituted or substituted
with from 1 to 3 substituents selected from
phenyl,
an alkyl group having from 1 to 6 carbon atoms and
which is straight or branched,
an alkoxy group having from 1 to 6 carbon atoms
and which is straight or branched;
hydroxy,
phenoxy,
fluorine,
chlorine,
bromine,
vitro,
trifluoromethyl,
-COOH,
-COOalkyl wherein alkyl has from 1 to 4 carbon
atoms and is straight or branched,
-(CH2)pNR3R4 wherein p, R3 and R4 have the
meanings defined above;
(c) arylalkyl;
(d) a straight or branched alkyl chain having
from 1 to 20 carbon atoms and which is saturated or
,, contains from 1 to 3 double bonds; or
(e) adamantyl or a cycloalkyl group wherein the
cycloalkyl moiety has from 3 to 6 carbon atoms;
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with the provisos:
(i) where X is (CH2)n, Y is oxygen, and R1 is a
substituted phenyl. then R2 is a
substituted phenyl;
(ii) where Y is oxygen, X is (CH2)n, R2 is
phenyl or aaphthyl, then R1 is not a
straight or branched alkyl chain; and
(iii) the following compounds are excluded:
X Y R R1 R2
CH2 O H (CH2)2CH3 Ph
CH2 O H CH3 Ph
CH2 O H Me i i-Pr
The ACAT inhibitor for use in the novel method may
be selected from any effective compound, especially
compounds of Fonaula I above, especially sulfamic acid,
([2,4,6-tris ~ ethylethyl)-phenyl]acetyl]-, 2,6-bis~(1-
methylethyl)phenyl ester; 2,6-bis(1-methylethyl)phenyl-
[[2,6-bis(1-methylethyl)-phenyl]sulfonyl]carbamate
monosodium salt; N-(2.6-di-isopropyl-phenyl)-2-pheayl-
malonamic acid dodecyl ester; N-(2,6-diisopropyl-
phenyl)-2-(2-dodecyl-2H-tetrazol-5-yl)-2-phenyl-
acetamide; 2,2-dimethyl-N-(2,4,6-trimethoxyphenyl)-
docecanamide; and N-[2,6-bis(1-methylethyl)phenyl]-
N'-[[1-(4-(dimethyl-amino)phenyl]cyclopentyl]methyl
urea monohydrochloride.
The doses of ACAT inhibitor contemplated for use
in this invention an about 50 to 1500 mg per day,
preferably given in single or divided doses.
One especially useful ACAT inhibitor is
2,6-bis(1-methylethyl)phenyl [[2,4.6-tris(1-
methylethyl)phenyl]acetyl]sulfamate disclosed in United
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States Patent Number 5,491,172.
Other ACAT inhibitors are 2,6-bis-(1-methylethyl)-
phenyl[[2,6-bis(1-methylethyl)phenoxy]-sulfonyl]-
carbamate monosodium salt; and similar compounds are
disclosed in United States Patent Number 5,245,068;
N-(2,6-diisopropyl-phenyl)-2-phenyl-malonamic acid
dodecyl ester; and similar compounds are disclosed in
United States Patent Number 5,420,339; N-(2,6-diiso-
propyl-phenyl)-2-(2-dodecyl-2H-tetrazol-5-yl)-2-phenyl-
acetamide; and similar compounds are disclosed in
United States Patent Number 5,366,987 and divisional
5,441,975; N-[2,6-bis(1-methylethyl)phenyl]-N'-[[1-[4-
(dimethylamino)phenyl.]cyclo-penty]methyl]urea
monohydrochloride disclosed in United States Patent
Number 5,015,644 and 2,2-dimethyl-N-(2,4,6-
trimethoxyphenyl) docecanamide and similar compounds
disclosed in United States Patent Number 4,716,175.
The lipid modifying and antiatherosclerotic action
of 2,6-bis(1-methylethyl)phenyl[[2,4,6-tris(1-
methylethyl)phenyl]acetyl]sulfamate, atorvastatin, and
the combination of both compounds was assessed in a
rabbit model of atherosclerosis in which the
combination of hypercholesterolemia and chronic
endothelial denudation of the iliac-femoral artery
promotes lesion development.
The model of atherosclerosis consists of a lesion
induction phase of 15 weeks followed by an 8-week drug
intervention phase. A main feature of the protocol is
that after 9 weeks of a 0.5% cholesterol (C), 3% peanut
(PNO), 3% coconut (CNO) oil diet plasma, cholesterol
levels are normalized by feeding a 0% C, 3% PNO, 3% CNO
diet prior to drug administration. The animals are
randomized based on their mean plasma total cholesterol
levels and administered the 0% C, 3% PNO, 3% CNO diet
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either alone or containing N-(2,6-diisopropyl-phenyl)-
2-(2-dodecyl-2H-tetrazol-5-yl)-2-phenyl-acetamide at
mg/kg, atorvastatin at 5 mg/kg, or N-(2,6-diiso-
propyl-phenyl)-2-(2-dodecyl-2H-tetrazol-5-yl)-2-phenyl-
5 acetamide + atorvastatin at 10 + 5 mg/kg for the next ,
8 weeks.
Relative to the untreated, cholesterol-fed
control, plasma total cholesterol levels were unchanged
by 2,6-bis(1-methylethyl)phenyl[[2,4,6-tris(1-
10 methylethyl)phenyl]acetyl]sulfamate but reduced 43~ and
67~ with atorvastatin and 2,6-bis(1-methylethyl)-
phenyl[[2,4,6-tris(1-methylethyl)phenyl]acetyl]-
sulfamate + atorvastatin, respectively. Associated
with the changes in plasma total cholesterol were
marked alterations in the plasma lipoprotein
distribution. 2,6-Bis(1-methylethyl)phenyl[[2,4,6-
tris(1-methylethyl)phenyl]acetyl]sulfamate reduced
VLDL-cholesterol (VLDL-C) and increased
LDL-cholesterol (LDL-C); atorvastatin had limited
effect; and upon combination treatment ~ VLDL-C and
LDL-C were reduced, and ~ HDL-cholesterol was
increased.
Results are summarized in Table I below.
r
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TABLE I. Lipoprotein Distribution Expressed as
Percent of Total Plasma Cholesterol
VLDL LDL HDL
Progression Control 16 60 24
' 5 2,6-bis(1-methylethyl)- 5 73 22
phenyl[[2,4,6-tris(1-
methylethyl)phenyl]-
acetyl]sulfamate (10 mg/kg)
Atorvastatin (5 mg/kg) 14 48 3$
2,6~-bis(1-methylethyl)- 4 35 60
phenyl[[2,4,6-tris(1-
methylethyl)phenyl]-
acetyl]sulfamate +
Atorvastatin (10 + 5 mg/kg)
Analysis of the vascular cholesteryl ester (CE)
enrichment, incidence of complex atherosclerotic
lesions, gross extent of thoracic aortic
atherosclerosis, and size and composition of the
iliac-femoral lesion have also been performed. 2,6-
Bis(1-methylethyl)phenyl[[2,4,6-tris(1-methylethyl)-
phenyl]acetyl]sulfamate had no effect on the CE
enrichment of the thoracic aorta and iliac-femoral
artery and on the gross extent of lesion coverage in
the thoracic aorta; however, the incidence of complex
fibrous plaques within the iliac-femoral artery was
reduced from 50~ to 14~. Atorvastatin reduced the CE
enrichment of both vascular regions by 27~ to 41~
without changing the gross extent of thoracic lesions
and incidence of fibrous plaques. 2,6-Bis(1-
methylethyl)phenyl[[2,4,6-tris(1-methylethyl)-
phenyl]acetyl]sulfamate + atorvastatin had no effect on
the CE enrichment of the thoracic aorta and gross
extent of thoracic aortic lesions; however, the
iliac-femoral CE content was reduced 23~ and incidence
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of fibrous plaques was decreased to 17~. Comparison of
the data relative to the time zero control, i.e., prior
to drug administration, atorvastatin alone and in
combination with 2,6-bis(1-methylethyl)phenyl[[2,4,6-
tris(1-methylethyl)phenyl]acetyl]sulfamate ,
significantly reduced the CE enrichment of the
iliac-femoral artery. Morphometric analysis of the
iliac-femoral artery revealed that atorvastatin reduced
the lesion size, while the combination of atorvastatin
and 2,6-bis(1-methylethyl)phenyl[[2,4,6-tris(1-
methylethyl)-phenyl]acetyl]sulfamate significantly
decreased the monocyte-macrophage content of the lesion
without changing lesion size. 2,6-Bis(1-
methylethyl)phenyl[[2,4,6-tris(1-methylethyl)-
phenyl]acetyl]sulfamate alone had no effect on the
iliac-femoral lesion size or composition.
Therefore, it is clear that a combination of
N-(2,6-diisopropyl-phenyl)-2-(2-dodecyl-2H-tetrazol-
5-yl)-2-phenyl-acetamide and atorvastatin administered
in a chow/fat diet results in a greater reduction in
plasma apo B-containing lipoprotein than either alone
and that a normalization of the plasma lipoprotein
distribution is achieved. Atorvastatin not only blunts
the cholesteryl ester enrichment of the vasculature but
also decrease the lipid enrichment of a pre-existing
atherosclerotic lesion. 2,6-Bis(1-
methylethyl)phenyl[[2,4,6-tris(1-methylethyl)-
phenyl]acetyl]sulfamate + atorvastatin reduces the CE
enrichment of pre-existing atherosclerotic lesions to
the same extent as atorvastatin alone, but the
atherosclerotic lesions are less complicated with
respect to their histologic character.
For preparing the pharmaceutical compositions from
the compounds of this invention, inert, pharmaceu- a
tically acceptable carriers can be either solid or
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liquid. Solid form preparations include powders,
tablets, dispersible granules, capsules, and cachets.
A solid carrier can be one or more substances
which may also act as diluents, flavoring agents,
solubilizers, lubricants, suspending agents, binders,
or tablet disintegrating agents; it can also be an
encapsulating material.
In powders, the carrier is a finely divided solid
which is in a mixture with the finely divided active
component. In tablets, the active component is mixed
with the carrier having the necessary binding
properties in suitable proportions and compacted in the
shape and size desired.
Powders and tablets preferably contain between
about 5$ to about 70$ by weight of the active
ingredient. Suitable carriers are magnesium
dicarbonate, magnesium stearate, talc, lactose, sugar,
pectin, dextrin, starch, tragacanth, methyl cellulose,
sodium carboxymethyl cellulose, a low-melting wax,
cocoa butter, and the like.
The term "preparation" is intended to include the
formulation of the active compound with encapsulating
material as a carrier providing a capsule in which the
active component (with or without other carriers) is
surrounded by a carrier, which is thus in association
with it. In a similar manner cachets or transdermal
systems are also included.
Tablets, powders, cachets, and capsules can be
used as solid dosage forms suitable for oral
administration.
Liquid form preparations include solutions,
suspensions, or emulsions suitable for oral
administration. Aqueous solutions for oral
~ administration can be prepared by dissolving the active
compound in water and adding suitable flavorants,
coloring agents, stabilizers, and thickening agents as
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desired. Aqueous suspensions for oral use can be made
by dispersing the finely divided active component in
water together with a viscous material such as natural -
or synthetic gums, resins, methyl cellulose, sodium
carboxymethylcellulose, and other suspending agents
known to the pharmaceutical formulation art.
Preferably, the pharmaceutical preparation is in
unit dosage form. In such form, the preparation is
divided into unit doses containing appropriate
quantities of the active component. The unit dosage
form can be a packaged preparation containing discrete
quantities of the preparation, for example, packeted
tablets, capsules, and powders in vials or ampoules.
The unit dosage form can also be a capsule, cachet, or
tablet itself, or it can be the appropriate number of
these packaged forms.
The dosage forms are well within the skill of a
physician who will be familiar with such factors as
time of day and other pertinent considerations.