METHOD FOR TREATING ALZHEIMER'S DISEASE AND RELATED CONDITIONS

1 . A method for treating or preventing a disease involving deposition of β-amyloid (Aβ) in the brain which comprises administering to a patient in need thereof a therapeutically effective amount of a gamma-secretase inhibitor (GSI) by an intermittent dosing regimen.

2 . A method according to claim 1 wherein the disease is Alzheimer's disease.

3 . A method according to claim 1 wherein the intermittent dosing regimen comprises a repeating cycle of GSI administration on 1 to 3 consecutive days followed by at least 4 days of rest.

4 . A method according to claim 3 wherein the GSI is administered on 3 consecutive days followed by 4 days of rest.

5 . A method according to claim 3 wherein the GSI is administered on 1 day followed by 6 days of rest.

6 . A method according to claim 1 wherein the GSI is a compound of formula I:

or pharmaceutically acceptable salt thereof, wherein:

X 1 is selected from the group consisting of: F and CN;

X 2 is selected from the group consisting of: F, Cl and CN;

X 3 is selected from the group consisting of: F, Br, Cl, CN, CF 3 , OCF 3 , C(O)—OCH 3 and S—CH 3 ;

X 4 is selected from the group consisting of: H, F and Cl;

R 1 is selected from the group consisting of:

(a) H,

(b) CH 3 ,

(c) —(CH 2 ) n —OR 3 ;

(d) —(CH 2 ) n —C(O)—OR 4 and

(e) —SO 2 —CF 3 ;

R 2 is H or CH 3 when the compound of formula I is in the cis configuration, otherwise R 2 is H;

R 3 is a five- or six-membered non-aromatic heterocycle having one oxygen heteroatom;

R 4 is H or CH 3 ; and

n is 1 to 4.

7 . A method according to claim 6 wherein X 1 and X 2 are F; X 3 is Cl; and X 4 is H.

8 . A method according to claim 6 wherein the GSI is a compound of formula:

or a pharmaceutically acceptable salt thereof.

9 . A method according to claim 1 wherein the GSI is a compound of formula II:

wherein:

m is 0 or 1;

Z represents CN, OR 2a , CO 2 R 2a or CON(R 2a ) 2 ;

R 1b represents H, C 1-4 alkyl or OH;

R 1c represents H or C 1-4 alkyl;

Ar 1 represents phenyl or pyridyl, either of which bears 0-3 substituents independently selected from halogen, CN, NO 2 , CF 3 , OH, OCF 3 , C 1-4 alkoxy or C 1-4 alkyl which optionally bears a substituent selected from halogen, CN, NO 2 , CF 3 , OH and C 1-4 alkoxy;

Ar 2 represents phenyl which is substituted in the 2- and 5-positions with halogen;

R 2a represents H, C 1-6 alkyl, C 3-6 cycloalkyl, C 3-6 cycloalkylC 1-6 alkyl, C 2-6 alkenyl, any of which optionally bears a substituent selected from halogen, CN, NO 2 , CF 3 , OR 2b , CO 2 R 2b , N(R 2b ) 2 , CON(R 2b ) 2 , Ar and COAr; or R 2a represents Ar; or two R 2a groups together with a nitrogen atom to which they are mutually attached may complete an N-heterocyclyl group bearing 0-4 substituents independently selected from ═O, ═S, halogen, C 1-4 alkyl, CN, NO 2 , CF 3 , OH, C 1-4 alkoxy, C 1-4 alkoxycarbonyl, CO 2 H, amino, C 1-4 alkylamino, di(C 1-4 alkyl)amino, carbamoyl, Ar and COAr;

R 2b represents H, C l-6 alkyl, C 3-6 cycloalkyl, C 3-6 cycloalkylC 1-6 alkyl, C 2-6 alkenyl, any of which optionally bears a substituent selected from halogen, CN, NO 2 , CF 3 , OH, C 1-4 alkoxy, C 1-4 alkoxycarbonyl, CO 2 H, amino, C 1-4 alkylamino, di(C 1-4 alkyl)amino, carbamoyl, Ar and COAr; or R 2b represents Ar; or two R 2b groups together with a nitrogen atom to which they are mutually attached may complete an N-heterocyclyl group bearing 0-4 substituents independently selected from ═O, ═S, halogen, C 1-4 alkyl, CN, NO 2 , CF 3 , OH, C 1-4 alkoxy, C 1-4 alkoxycarbonyl, CO 2 H, amino, C 1-4 alkylamino, di(C 1-4 alkyl)amino, carbamoyl, Ar and COAr;

Ar represents phenyl or heteroaryl bearing 0-3 substituents selected from halogen, C 1-4 alkyl, CN, NO 2 , CF 3 , OH, C 1-4 alkoxy, C 1-4 alkoxycarbonyl, amino, C 1-4 alkylamino, di(C 1-4 alkyl)amino, carbamoyl, C 1-4 alkylcarbamoyl and di(C 1-4 alkyl)carbamoyl;

or a pharmaceutically acceptable salt thereof.

10 . A method according to claim 9 wherein the GSI is cis-4-[(4-chlorophenyl)sulfonyl]-4-(2,5-difluorophenyl)cyclohexanepropanoic acid or the sodium salt thereof.

11 . A method according to claim 1 wherein the GSI is a compound of formula (III):

or a pharmaceutically acceptable salt thereof;

wherein R 4 is —CH═CHCH 2 N(R 16 ) 2 where —N(R 16 ) 2 is morpholin-4-yl, 4-trifluoromethylpiperidin-1-yl, 5-aza-2-oxabicyclo[2.2.1]hept-1-yl, 4,4-difluoropiperidin-1-yl, 4-hydroxy-4-trifluoromethylpiperidin-1-yl, 4-methylpiperidin-1-yl, 3-oxo-4-phenylpiperazin-1-yl, 3-oxo-4-cyclohexylpiperazin-1-yl, 3-oxo-piperazin-1-yl, N-(tetrahydrofuran-3-yl)amino, N-methyl-N-(tetrahydrofuran-3-yl)amino, N-(tetrahydropyran-4-yl)amino, N-methyl-N-(tetrahydropyran-4-yl)amino, N-(dioxanylmethyl)amino, N-[(tetrahydropyran-2-yl)methyl]amino, 3-hydroxypiperidin-1-yl, 5-aza-2-oxabicyclo[5.4.0]undeca-7,9,11-trien-5-yl, 2-(phenoxymethyl)morpholin-4-yl, N-[(4-phenylmorpholin-2-yl)methyl]amino, 3,3-difluoropyrrolidin-1-yl, N-(2,2,2-trifluoroethyl)amino, or 3-(pyridin-3-yl)pyrrolidin-1-yl.

12 . A method according to claim 1 wherein the GSI is a compound of formula IV:

or a pharmaceutically acceptable salt thereof;

wherein X 2 is a bivalent pyrazole, imidazole, triazole, oxazole, isoxazole, thiazole, isothiazole, thiadiazole or 1,3,4-oxadiazole residue optionally bearing a hydrocarbon substituent comprising 1-5 carbon atoms which is optionally substituted with up to 3 halogen atoms; and R is selected from:

(i) CF 3 or an alkyl group of up to 6 carbon atoms, optionally substituted with halogen, CF 3 , CHF 2 , CN, OH, CO 2 H, C 2-6 acyl, C 1-4 alkoxy or C 1-4 alkoxycarbonyl;

(ii) a non-aromatic heterocyclic group comprising up to 7 ring atoms of which up to 3 are chosen from N, O and S and the remainder are carbon, bearing 0-3 substituents independently selected from oxo, halogen, CN, C 1-6 alkyl, OH, CF 3 , CHF 2 , CH 2 F, C 2-6 acyl, CO 2 H, C 1-4 alkoxy and C 1-4 alkoxycarbonyl;

(iii) phenyl or 6-membered heteroaryl, either of which bears 0-3 substituents independently selected from halogen, CF 3 , CHF 2 , CH 2 F, NO 2 , CN, OCF 3 , C 1-6 alkyl and C 1-6 alkoxy; and

(iv) N(R a ) 2 where each R a independently represents H or C 1-6 alkyl which is optionally substituted with halogen, CF 3 , CHF 2 , CN, OH, C 1-4 alkoxy or C 1-4 alkoxycarbonyl.

13 . A method according to claim 12 wherein X 2 represents 5-substituted-thiazol-2-yl, 5-substituted-4-methylthiazol-2-yl, 5-substituted-1-methylpyrazol-3-yl, 1-substituted-imidazol-4-yl or 1-substituted-1,2,4-triazol-3-yl; and R represents 4-fluorophenyl, 4-chlorophenyl or 3,4-difluorophenyl.

14 . A method according to claim 1 wherein the GSI is a compound of formula:

wherein the bonds indicated by wavy lines are mutually cis with respect to the cyclohexane ring;

R 3 represents H or a hydrocarbon group of up to 10 carbon atoms, optionally substituted with CF 3 , CHF 2 , halogen, CN, OR 5 , COR 5 , CO 2 R 5 , OCOR 6 , N(R 5 ) 2 , CON(R 5 ) 2 or NR 5 COR 6 ;

R 5 represents H or C 1-4 alkyl;

R 6 represents C 1-4 alkyl; and

Ar 1 and Ar 2 independently represent phenyl or heteroaryl, either of which bears 0-3 substituents independently selected from halogen, CN, NO 2 , CF 3 , CHF 2 , OH, OCF 3 , CHO, CH═NOH, C 1-4 alkoxy, C 1-4 alkoxycarbonyl, C 2-6 acyl, C 2-6 alkenyl and C 1-4 alkyl which optionally bears a substituent selected from halogen, CN, NO 2 , CF 3 , OH and C 1-4 alkoxy;

or a pharmaceutically acceptable salt thereof.

15 . A method according to claim 14 wherein the GSI is selected from:

(4aRS,6RS,8aSR)-6-(2,5-difluorophenyl)-6-{[4-(trifluoromethyl)phenyl]sulfonyl}octahydro-1H-2,1-benzothiazine 2,2-dioxide;

(3R,4aS,6S,8aR)-6-(2,5-difluorophenyl)-3-ethyl-6-{[4-(trifluoromethyl)phenyl]sulfonyl}octahydro-1H-2,1-benzothiazine 2,2-dioxide;

(3S,4aS,6S,8aR)-6-(2,5-difluorophenyl)-3-ethyl-6-{[4-(trifluoromethyl)phenyl]sulfonyl}octahydro-1H-2,1-benzothiazine 2,2-dioxide;

(3RS,4aRS,6RS,8aSR)-6-(2,5-difluorophenyl)-3-isopropyl-6-{[4-(trifluoromethyl)phenyl]sulfonyl}octahydro-1H-2,1-benzothiazine 2,2-dioxide;

(3SR,4aRS,6RS,8aSR)-6-(2,5-difluorophenyl)-3-isopropyl-6-{[4-(trifluoromethyl)phenyl]sulfonyl}octahydro-1H-2,1-benzothiazine 2,2-dioxide; and

(3R,4aS,6S,8aR)-6-[(4-chlorophenyl)sulfonyl]-6-(2,5-difluorophenyl)-3-ethyloctahydro-1H-2,1-benzothiazine 2,2-dioxide;

and the pharmaceutically acceptable salts thereof.

16 . A method according to claim 1 wherein the GSI is a compound of formula:

or a pharmaceutically-acceptable salt thereof,

wherein X is Cl and Y is F; or X and Y are both CF 3 .