WO2007028769A1

WO2007028769A1 - Monoamine neurotransmitter re-uptake inhibitor for neuroprotection

Info

Publication number: WO2007028769A1
Application number: PCT/EP2006/065896
Authority: WO
Inventors: Klaus Bornemann; Holger Rosenbrock; Frank Sams-Dodd; Bastian Hengerer; Jens Damsgaard Mikkelsen
Original assignee: Neurosearch A/S
Priority date: 2005-09-05
Filing date: 2006-09-01
Publication date: 2007-03-15

Abstract

The invention relates to the use of a monoamine neurotransmitter re-uptake inhibitor comprising a 2,3-disubstituted tropane moiety for the preparation of a medicament for inducing cerebral progenitor proliferation and synaptic plasticity in patients in need thereof as they suffer from a mental disease in an early stage.

Description

MONOAMINE NEUROTRANSMITTER RE-UPTAKE INHIBITOR FOR NEUROPROTECTION

The invention relates to the use of a monoamine neurotransmitter re-uptake inhibitor comprising a 2,3-disubstituted tropane moiety optionally in the form of its physiologically acceptable acid addition salts for the preparation of a medicament for cerebral neuroprotection, in particular for inducing cerebral progenitor proliferation and synaptic plasticity. Such medicaments are useful in the prophylactic, non-symptomatic treatment of patients that not yet symptomatically suffer from Alzheimer's or

Parkinson's Disease (abbreviated AD, PD respectively) as well as for the deceleration of the progression of these such diseases.

BACKGROUND OF THE INVENTION

Due to the changes in ageing statistics the number of patients suffering from mental diseases due to loss of neurons is increasing, in particular in the Western world. Many of such patients eventually lose self-control and the ability to care for themselves, and will become dependent on part or full care every day. Among the more known diseases are AD and PD. In case of Parkinson's disease a progressive loss of nigral dopaminergic neurons occurs, whereas in AD hippocampal and cortical regions are majorly affected by neuronal apoptosis. Although there are several attempts to stop the disease via medication, they fail to heal the disease. Therefore, there is an essential need for better medication to at least modify the disease or to protect neurons. One of the proteins that reveals neuroprotective features is the brain- derived neurotrophic factor (BDNF), which belongs to neurotrophins and affects neuronal survival, differentiation and synaptic plasticity. Loss of neurons may be compensated by neuroprogenitor-proliferation. One marker for such proliferation is cyclin D2, a cell cycle gene (protein) that may contribute to progenitor cell proliferation. It is upregulated in multipotent neural stem cells. The initiation of expression of these proteins may contribute to neuroprotection and neuroprogenitor-proliferation.

BRIEF DESCRIPTION OF THE INVENTION

Surprisingly, it has been found, that a monoamine neurotransmitter reuptake inhibitor comprising a 2,3-disubstituted tropane moiety optionally in the form of its physiologically acceptable acid addition salts induces the cerebral production of BDNF and in turn may improve synaptic plasticity. Additionally, cerebral progenitor proliferation was observed. Both effects, although different and independent in nature are promising starting points for an improved treatment of diseases in that the loss of neurons is a significant feature. Accordingly, one embodiment of the current invention relates to the use of a monoamine neurotransmitter re-uptake inhibitor comprising a 2,3-disubstituted tropane moiety optionally in the form of its physiologically acceptable acid addition salts for the preparation of a medicament to reverse the loss of neurons or neuronal activity by either inducing the synthesis of BDNF in the brain, with the option to enhance synaptic plasticity and/or by inducing cerebral progenitor proliferation. Thus the invention is of interest in the treatment of a disease or condition associated with the degradation of cerebral progenitors, the loss of neuronal activity in the brain, the loss of synaptic activity in the brain, the degeneration of cerebral cells in the brain.

Preferably the invention relates to the use of a monoamine neurotransmitter re-uptake inhibitor comprising a 2,3-disubstituted tropane moiety optionally in the form of its physiologically acceptable acid addition salts for the preparation of a medicament for the prophylactic and the progression decelerating treatment of Alzheimer's or Parkinson's Disease, mild cognitive impairment (MCI), Down's syndrome, Hereditary Cerebral Hemorrhage with Amyloidosis of the Dutch Type, cerebral beta-amyloid angiopathy and preventing its potential consequences such as single and recurrent lobar hemorrhages, other degenerative dementias, including dementias of mixed vascular and degenerative origin, dementia associated with Parkinson's disease, dementia associated with progressive supranuclear palsy, dementia associated with cortical basal degeneration, and diffuse Lewy body type AD. Of particular interest are early PD, not-yet symptomatic PD, early, mild or moderest AD, not-yet symptomatic AD, and MCI.

DETAILED DESCRIPTION OF THE INVENTION

As a rule the monoamine neurotransmitter re-uptake inhibitor comprising a

2,3-disubstituted tropane moiety are those which are disclosed by International patent applications WO 93/09814 and WO 97/30997.

Preferably the monoamine neurotransmitter re-uptake inhibitor comprising a 2,3-disubstituted tropane moiety are compounds of the general formula (I)

( I ) or a pharmaceutical acceptable addition salt thereof or the N-oxide thereof, wherein R¹ is hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkylalkyl or 2-hydroxyethyl; R⁶ is CH₂-X-R³, wherein X is O, S, or NR'; wherein

R' is hydrogen or alkyl; and

R³ is alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkylalkyl, or-CO-alkyl; heteroaryl which may be substituted one or more times with alkyl, cycloalkyl, or cycloalkylalkyl; phenyl which may be substituted one or more times with substituents selected from the group consisting of halogen, CF₃, CN, alkoxy, alkyl, alkenyl, alkynyl, amino, nitro, and heteroaryl; phenylphenyl; pyridyl which may be substituted one or more times with substituents selected from the group consisting of halogen, CF₃, CN, alkoxy, alkyl, alkenyl, alkynyl, amino, nitro, and heteroaryl; thienyl which may be substituted one or more times with substituents selected from the group consisting of halogen, CF₃, CN, alkoxy, alkyl, alkenyl, alkynyl, amino, nitro, and heteroaryl ; or benzyl which may be substituted one or more times with substituents selected from the group consisting of halogen, CF₃, CN, alkoxy, alkyl, alkenyl, alkynyl, amino, nitro, and heteroaryl; or (CH₂)_nCO₂R⁷, COR⁷, or CH₂R⁸, wherein

R⁷ is alkyl, cycloalkyl, or cycloalkylalkyl; phenyl which may be substituted one or more times with substituents selected from the group consisting of halogen,

CF₃, CN, alkoxy, alkyl, alkenyl, alkynyl, amino, nitro, and heteroaryl ; phenylphenyl ; pyridyl which may be substituted one or more times with substituents selected from the group consisting of halogen, CF₃, CN, alkoxy, alkyl, alkenyl, alkynyl, amino, nitro, and heteroaryl; or thienyl which may be substituted one or more times with substituents selected from the group consisting of halogen, CF₃, CN, alkoxy, alkyl, alkenyl, alkynyl, amino, nitro, and heteroaryl; or benzyl; n is 0 or 1 ; and R⁸ is O-phenyl which may be substituted one or more times with substituents selected from the group consisting of halogen, CF₃, CN, alkoxy, alkyl, alkenyl, alkynyl, amino, nitro, and heteroaryl; or O-CO-phenyl which may be substituted one or more times with substituents selected from the group consisting of halogen, CF₃, CN, alkoxy, alkyl, alkenyl, alkynyl, amino, nitro, and heteroaryl; or CH=NOR³ ; wherein R³ is hydrogen; alkyl, cycloalkyl, cycloalkylalkyl, alkenyl, alkynyl or aryl; all of which may be substituted with -COOH; -COO-alkyl; -COO-cycloalkyl; or phenyl which may be substituted one or more times with substituents selected from the group consisting of halogen, CF₃, CN, alkyl, cycloalkyl, alkoxy, cycloalkoxy, alkenyl, alkynyl, amino, and nitro; R⁴ is phenyl, 3,4-methylenedioxyphenyl, benzyl, naphthyl, or heteroaryl all of which may be substituted one or more times with substituents selected from the group consisting of halogen, CF₃, CN, alkoxy, cycloalkoxy, alkyl, cycloalkyl, alkenyl, alkynyl, amino, nitro, and heteroaryl.

In a special embodiment of the compound of general formula I, R⁶ is 1 ,2,4- oxadiazol-3-yl which may be substituted in the 5 position with alkyl, cycloalkyl, or cycloalkylalkyl; phenyl which may be substituted one or more times with substituents selected from the group consisting of halogen, CF₃, CN, alkoxy, alkyl, alkenyl, alkynyl, amino, nitro, and heteroaryl; phenylphenyl; or benzyl which may be substituted one or more times with substituents selected from the group consisting of halogen, CF₃, CN, alkoxy, alkyl, alkenyl, alkynyl, amino, nitro, and heteroaryl; or 1 ,2,4-oxadiazol-5-yl which may by substituted in the 3 position with alkyl, cycloalkyl, or cycloalkylalkyl; phenyl which may be substituted one or more times with substituents selected from the group consisting of halogen, CF₃, CN, alkoxy, alkyl, alkenyl, alkynyl, amino, nitro, and heteroaryl; phenylphenyl; benzyl which may be substituted one or more times with substituents selected from the group consisting of halogen, CF₃, CN, alkoxy, alkyl, alkenyl, alkynyl, amino, nitro, and heteroaryl; pyridyl which may be substituted one or more times with substituents selected from the group consisting of halogen, CF₃, CN, alkoxy, alkyl, alkenyl, alkynyl, amino, nitro and heteroaryl; or thienyl which may be substituted one or more times with substituents selected from the group consisting of halogen, CF₃, CN, alkoxy, alkyl, alkenyl, alkynyl, amino, nitro and heteroaryl. In a further special embodiment of the compound of general formula (I), R⁶ is CH₂-X-R³, wherein X is O, S, or NR'; wherein R' is hydrogen or alkyl; and R³ is alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkylalkyl, or-CO-alkyl. In a still further embodiment of the compound of general formula (I), R⁶ is CH=NOR³; wherein R³ is hydrogen; alkyl, cycloalkyl, cycloalkylalkyl, alkenyl, alkynyl or aryl; all of which may be substituted with -COOH; -COO-alkyl; -COO-cycloalkyl; or phenyl which may be substituted one or more times with substituents selected from the group consisting of halogen, CF₃, CN, alkyl, cycloalkyl, alkoxy, cycloalkoxy, alkenyl, alkynyl, amino, and nitro.

In a further special embodiment of the compound of general formula (I), R⁴ is phenyl, which is substituted once or twice with substituents selected from the group consisting of halogen, CF₃, CN, alkoxy, cycloalkoxy, alkyl, cycloalkyl, alkenyl, alkynyl, amino, nitro, and heteroaryl.

In a more special embodiment, R⁴ is phenyl substituted once or twice with chlorine.

In a further special embodiment, the tropane derivative having dopamine reuptake inhibitor activity is a (1 R,2R,3S) -2, 3-disubstituted tropane derivative of formula I.

In a still further embodiment, the tropane derivative having dopamine reuptake inhibitory activity is a compound of general formula I wherein R⁶ is -CH₂-X-R³, wherein X is O or S, and R³ is methyl, ethyl, propyl, or cyclopropylmethyl; -CH=NOR³; wherein R³ is hydrogen or alkyl, or 1 ,2,4-oxadiazol-5-yl which may by substituted in the 3 position with alkyl.

In a still further embodiment, the tropane derivative having dopamine reuptake inhibitory activity is a compound of general formula I wherein R¹ is hydrogen, methyl, ethyl or propyl.

In a still further embodiment, the tropane derivative having dopamine reuptake inhibitory activity is a compound of general formula I wherein R⁴ is 3,4- dichlorophenyl.

More preferably those monoamine neurotransmitter re-uptake inhibitor comprising a 2, 3-disubstituted tropane moiety are compounds of formula (II)

wherein

R¹ represents a hydrogen atom or a C-i-6 alkyl group, preferably a hydrogen atom, a methyl or an ethyl group; R² each independently represents a halogen atom or a CF₃ or cyano group, preferably a fluorine, chlorine or bromine atom;

R³ represents a hydrogen atom or a C_h alky! or Cs-β-cycloalkyl-d-s-alkyl group, preferably a methyl, ethyl or n-propyl group; and m is 0 or an integer from 1 to 3, preferably 1 or 2; or a tautomer, a pharmaceutically acceptable salt, solvate, or physiologically functional derivative thereof.

As used herein, the expression "alkyl" in particular refers to "Cι-6 alkyl" both of which include methyl and ethyl groups, and straight-chained and branched propyl, butyl, pentyl and hexyl groups. Particular alkyl groups are methyl, ethyl, n-propyl, isopropyl and t-butyl.

The expression "cycloalkyl" as used herein in particular refers to "C3-6 cycloalkyl" both of which include cyclic propyl, butyl, pentyl and hexyl groups such as cyclopropyl and cyclohexyl.

As used herein, the expression "alkenyl" in particular refers to "C₂-₆ alkenyl".

As used herein, the expression "alkynyl" in particular refers to "C₂-6 alkynyl"

The term "halogen" as used herein includes fluorine, chlorine, bromine and iodine, of which fluorine and chlorine are preferred. As used herein, the expression "heteroaryl" in particular refers to Cs-₇ membered ring systems with 1 , 2 or 3 heteroatoms selected from the group of N, O, S, such as pyridinyl, pyrrolyl, thienyl, furyl and the like.

The term "physiologically functional derivative" as used herein includes derivatives obtained from the compound of formula (I) under physiological conditions, these are for example N-oxides, which are formed under oxidative conditions.

The term "pharmaceutically acceptable acid addition salt" as used herein includes those salts which are selected from among the acid addition salts formed with hydrochloric acid, hydrobromic acid, sulphuric acid, phosphoric acid, methanesulphonic acid, acetic acid, fumaric acid, succinic acid, lactic acid, citric acid, tartaric acid and maleic acid, the salts obtained from hydrochloric acid, hydrobromic acid, sulphuric acid, phosphoric acid and acetic acid being particularly preferred. The salts of citric acid are of particular significance.

In a special embodiment, the tropane derivative having dopamine reuptake inhibitor activity is a compound of the general formula (I) selected from: (1 R,2R,3S)-2-(3-Cyclopropyl-1 ,2,4-oxadiazol-5-yl)-3- (4-fluorophenyl) tropane; (1 R,2R,3S)-2-(3-Phenyl-1 ,2,4-oxadiazol-5-yl)-3-(4-fluorophenyi) tropane; (1 R,2R,3S)-2-(3-Phenyl-1 ,2,4-oxadiazol-5-yl)-3-(4-methylphenyl)-tropane; (1 R,2R,3S)-2-(3-Benyl-1 ,2,4-oxadiazol-5-yl)-3-(4-fluorophenyl) tropane; (1 R,2R,3S)-2-(3-(4-Phenyl-phenyl)-1 ,2,4-oxadiazol-5-yl)-3-(4-fluorophenyl) tropane;

(1 R,2R,3S)-2-(3-Phenyl-1 ,2,4-oxadiazol-5-yl)-3-(2-naphthyl) tropane;

(1 R,2R,3S)-3-(3,4-Dichlorophenyl) tropane-2-aldoxime;

(1 R,2R,3S)-3-(3,4-Dichlorophenyl)-tropane-2-O-methyl-aldoxime; (1 R,2R,3S)-3-(3,4-Dichlorophenyl)tropane-2-O-benzyl-aldoxime;

(1 R,2R,3S)-3-(3,4-Dichlorophenyl) tropane-2-O-ethoxycarbonylmethyl-aldoxime;

(1 R,2R,3S)-3-(3,4-Dichlorophenyl) tropane-2-O-methoxycarbonylmethyl-aldoxime;

(1 R,2R,3S)-3-(3,4-Dichlorophenyl)tropane-2-O-(1 -ethoxycarbonyl-1 , 1 -dimethyl- methyl)-aldoxime; (1 R,2R,3S)-3-(3,4-Dichlorophenyl) tropane-2-O-carboxymethyl-2-aldoxime;

(1 R,2R,3S)-N-Normethyl-3-(3,4-dichlorophenyl) tropane-2-O-methyl-aldoxime;

(1 R,2R,3S)-N-Normethyl-3-(3,4-dichlorophenyl) tropane-2-O-benzyl-aldoxime;

(1 R,2R,3S)-3-(4-Methylphenyl) tropane-2-O-methyl-aldoxime;

(1 R,2R,3S)-3-(3,4-Dichlorophenyl)tropane-2-O-(1 , 1 -dimethylethyl)-aldoxime; (1 R,2R,3S)-3-(4-Chlorophenyl) tropane-2-O-aldoxime;

(1 R,2R,3S)-3-(4-Chlorophenyl) tropane-2-O-methylaldoxime hydrochloride;

(1 R,2R,3S)-3-(4-Chlorophenyl)tropane-2-O-methoxycarbonylmethyl-aldoxime;

(1 R,2R,3S)-3-(3,4-Dichlorophenyl) tropane-2-O- (2-propynyl)-aldoxime;

(1 R,2R,3S)-3-(3,4-Dichlorophenyl)tropane-2-O-(2-methylpropyl)-aldoxime; (1 R,2R,3S)-3-(3,4-Dichlorophenyl)tropane-2-O-cyclopropylmethyl-aldoxime;

(1 R,2R,3S)-3-(3,4-Dichlorophenyl) tropane-2-O-ethyl-aldoxime;

(1 R,2R,3S)-2-Methoxymethyl-3-(3,4-dichlorophenyl)-tropane;

(1 R,2R,3S)-2-lsopropoxymethyl-3-(3,4-dichlorophenyl)-tropane;

(1 R,2R,3S)-2-Ethoxymethyl-3-(3,4-dichlorophenyl)-tropane; (1 R,2R,3S)-2-Ethoxymethyl-3-(3,4-dichlorophenyl)-nortropane;

(1 R,2R,3S)-2-Cyclopropylmethyloxymethyl-3-(3,4-dichlorophenyl)-tropane;

(1 R,2R,3S)-2-Methoxymethyl-3-(4-chlorophenyl)-tropane;

(1 R,2R,3S)-N-Normethyl-2-methoxymethyl-3-(4-chlorophenyl)-tropane;

(1 R,2R,3S)-2-Ethoxymethyl-3-(4-chlorophenyl)-tropane; (1 R,2R,3S)-N-Normethyl-2-methoxymethyl-3-(3,4-dichlorophenyl)-tropane;

(1 R,2R,3S)-N-Normethyl-2-ethoxymethyl-3-(3,4-dichlorophenyl)-tropane;

(1 R,2R,3S)-N-Normethyl-2-ethoxymethyl-3-(4-chlorophenyl)-tropane;

(1 R,2R,3S)-N-Normethyl-2-cyclopropylmethyloxymethyl-3-(4-chlorophenyl)-tropane;

(1 R,2R,3S)-2-Cyclopropylmethyloxymethyl-3-(4-chlorophenyl)-tropane; (1 R,2R,3S)-2-Ethylthiomethyl-3-(3,4-dichlorophenyl)-tropane;

(1 R,2R,3S)-2-Hydroxymethyl-3-(4-fluorophenyl) tropane;

(1 R,2R,3S)-2-Hydroxymethyl-3-(3,4-dichlorophenyl) tropane; (1 R,2R,3S)-N-Normethyl-N-(tert-butoxycarbonyl)-2-hydroxymethyl-3-(3,4- dichlorophenyl) tropane;

(1 R,2R,3S)-2-Hydroxymethyl-3-(4-chlorophenyl) tropane;

(1 R,2R,3S)-2-(3-(2-Furanyl)-1 ,2,4-oxadiazol-5-yl)-3-(3,4-dichlorophenyl)-tropane; (1 R,2R,3S)-2-(3-(3-Pyridyl)-1 ,2,4-oxadiazol-5-yl)-3-(3,4-dichlorophenyl)-tropane;

(I R^R^SJ-N-Normethyl-N-allyl^-CS^-pyridyO-i ^^-oxadiazol-δ-yO-S-CS^- dichlorophenyl)-tropane;

(1 R,2R,3S)-N-Normethyl-N-ethyl-2-(3-(4-pyridyl)-1 ,2,4-oxadiazol-5-yl)-3-(3,4- dichlorophenyl)-tropane; (1 R,2R,3S)-N-Normethyl-N-(2-hydroxyethyl)-2-(3-(4-pyridyl)-1 ,2,4-oxadiazol-5-yl)-3-

(3,4-dichlorophenyl)-tropane;

(1 R,2R,3S)-N-Normethyl-2-(3-(4-pyridyl)-1 ,2,4-oxadiazol-5-yl)-3-(3,4-dichlorophenyl)- tropane;

(I R^R^SJ-N-Normethyl-N-allyl^-CS-CS-pyridyO-i ^^-oxadiazol-δ-yO-S-CS^- dichlorophenyl)-tropane;

(1 R,2R,3S)-N-Normethyl-N-allyl-2-(3-(2-pyridyl)-1 ,2, 4-oxadiazol-5-yl)-3-(3,4- dichlorophenyl)-tropane;

(1 R,2R,3S)-2-(3-(2-Thienyl)-1 ,2,4-oxadiazol-5-yl)-3-(4-chlorophenyl)-tropane;

(1 R,2R,3S)-2-(3-(2-Thienyl)-1 ,2,4-oxadiazol-5-yl)-3-(3,4-dichlorophenyl)-tropane; (1 R,2R,3S)-2-(3-(4-Pyridyl)-1 ,2,4-oxadiazol-5-yl)-3-(3,4-dichlorophenyl)-tropane;

(1 R,2R,3S)-2-(3-(2-Pyridyl)-1 ,2,4-oxadiazol-5-yl)-3-(3,4-dichlorophenyl)-tropane;

(1 R,2R,3S)-2-(3-(4-Pyridyl)-1 ,2,4-oxadiazol-5-yl)-3-(4-chlorophenyl)-tropane;

(1 R,2R,3S)-2-(3-(3-Pyridyl)-1 ,2,4-oxadiazol-5-yl)-3-(4-chlorophenyl)-tropane;

(1 R,2R,3S)-2-(3-(2-Pyridyl)-1 ,2,4-oxadiazol-5-yl)-3-(4-chlorophenyl)-tropane; (1 R,2R,3S)-2- (3-Phenyl-1 ,2,4-oxadiazol-5-yl)-3-(4-fluorophenyl)-tropane;

(1 R,2R,3S)-2-(3-Phenyl-1 ,2,4-oxadiazol-5-yl)-3- (4-methylphenyl)-tropane;

(1 R,2R,3S)-2-(3-Benzyl-1 ,2, 4-oxadiazol-5-yl)-3-(4-fluorophenyl)-tropane;

(1 R,2R,3S)-2-(3-(4-Phenylphenyl)-1 ,2, 4-oxadiazol-5-yl)-3-(4-fluorophenyl)-tropane;

(1 R,2R,3S)-2-(3-Phenyl-1 ,2,4-oxadiazol-5-yl)-3-(2-naphthyl)-tropane; (1 R,2R,3S)-2-(4-Chlorophenoxy-methyl)-3-(4-fluorophenyl)-tropane;

(1 R,2R,3S)-2-(4-Chlorophenoxy-methyl)-3-(4-fluorophenyl)-tropane;

(I R^R^S^^-Chlorophenoxy-methyO-S-CS^-dichlorophenyO-tropane;

(1 R,2R,3S)-2-(4-Chlorophenoxy-methyl)-3-(4-methylphenyl)-tropane;

(1 R,2R,3S)-2-(4-Benzoyloxy-methyl)-3-(4-fluorophenyl)-tropane; (1 R,2R,3S)-2-Carbomethoxy-3-(2-naphthyl)-tropane;

(1 R,2R,3S)-2-Carbomethoxy-3-(3,4-dichlorophenyl)-tropane;

(1 R,2R,3S)-2-Carbomethoxy-3-benzyl-tropane;

(1 R,2R,3S)-2-Carbomethoxy-3-(4-chlorophenyl)-tropane; (1 R,2R,3S)-2-Carbomethoxy-3-(4-methylphenyl)-tropane; (1 R,2R,3S)-2-Carbomethoxy-3-(1 -naphthyl)-tropane; (1 R,2R,3S)-2-Carbomethoxy-3-(4-phenylphenyl)-tropane; (1 R,2R,3S)-2-Carbomethoxy-3-(4-t-butyl-phenyl)-tropane; (1 R,2R,3S)-2-(4-Fluoro-benzoyl)-3-(4-fluorophenyl)-tropane; or a pharmaceutically acceptable addition salt thereof.

Most preferred are the compounds of formulae (III) and (IV)

or pharmaceutically acceptable salts thereof, in particular the citrates thereof.

Accordingly, one embodiment of the current invention relates to the use of a monoamine neurotransmitter re-uptake inhibitor comprising a 2,3-disubstituted tropane moiety optionally in the form of its physiologically acceptable acid addition salts for the preparation of a medicament for the prophylactic or the progression decelerating treatment of a disease mentioned at the beginning.

In particular the invention is for the use of a compound of formula I, preferably Il and more preferably III and/or IV, for the preparation of a medicament for the prophylactic treatment or to decelerate the progression of a disease associated with cerebral neuronal degradation and/or for to treat a mammal that profits from cerebral neuroprotection due to the danger of cerebral neurodegeneration. It is preferred to treat patients suffering from such a disease, while no typical symptoms have yet manifested (non-symptomatic treatment). In the context of the present invention it is understood that typical symptoms have manifested if a physician can diagnose the disease on basis of physical and/or behavioral symptoms with a likelihood as well used in the art. The terms "typical symptoms" or "diagnosis of the disease" do not include molecular biological signs or molecular biological diagnostic methods and the like on basis of which it can be concluded that a person is predisposed to suffer from such a disease or of which it can be concluded that the disease will break out (manifest) in the future or it can be concluded that the disease might have broken out but is in a symptom-free pre-state. The term "mammal" includes animals as well as man. Preferably, the invention is used to treat man. For further information concerning the diagnosis of AD see Neurology 1984; 34: 939-944. Among the diseases mentioned above the one that shall be treated with preference are diseases that respond to the induction of cerebral progenitor proliferation and/or amelioration of the cerebral synaptic plasticity and/or counteraction to the loss of neuronal activity and/or counteraction to the loss of synaptic activity. Among interesting diseases is mild to moderate dementia of the Alzheimer type (DAT). In the treatment option are also patients included that are at high risk for developing dementia of the Alzheimer type but that do not yet show signs thereof.

Among interesting diseases is mild to moderate Parkinson. In the treatment option are also patients included that are at high risk for developing dementia of the Parkinson type but that do not yet show signs thereof.

Moreover, the invention relates to the use of the compound of formula III for the preparation of a medicament for the non-symptomatic treatment of patients suffering from mild cognitive impairment (MCI) or age associated memory impairment (AAMI).

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is further illustrated by reference to the accompanying drawing, in which: Fig. 1 shows the regulation of BDNF (upper row) and Arc (lower row) transcripts in the hippocampus following short (5 days) and long-term (14 days) treatment with tesofensine. Rats were administered for 5 or 14 days and levels of transcripts were determined by in situ hybridization. Representative images of scanned autoradiograms from animals sub-chronically (5 days) and chronically (14 days) treated with either tesofensine or vehicle are shown.

Figs. 2A-B and 2C-D show the influence of sub-chronic (5 days) and chronic (14 days) of treatment with tesofensine relative to vehicle (n = 8) on the levels of BDNF mRNA expression (Fig. 2A and 2B) and Arc mRNA expression (Fig. 2C and 2D). Sections were subjected to in situ hybridization and quantification of the levels of the two transcripts was performed using densitometric analysis. BDNF mRNA levels in the CA3 region (Fig. 2A) and the granular cell layer of the dentate gyrus (Fig. 2B) revealed a significant increase in the CA3, but not in the granular cell layer. Arc mRNA expression in the CA1 region of the hippocampus (Fig. 2C) and in the parietal cortex (Fig. 2D) significantly increased after tesofensine for 14 days. Data are presented as relative increase in the tissue compared to control as mean ± SEM (n = 8). ^*P<0.05 (student's t-test).

Figs. 3A-D and 3E-F show NeuroD-positive cells that are non-mature neurons. Dual-labeling for NeuroD- and either NeuN (3A), GFAP (3B), Ki-67 (3C), or CcM 1 b (3D) revealed no co-localization of NeuroD and any of the other markers. Figs. 3E and 3F are representative images of dual labeling of Ki-67 (arrows marked with a star) and NeuroD (white arrows) immunoreactivity in the dentate gyrus of a rat treated for 14 days with vehicle and tesofensine. Fig. 4 shows quantification of Ki-67-immunopositive cells (4A), Ki-67 immunopositive cell clusters (4B), and NeuroD-immunopositive cells (4C) in the dentate gyrus of the rat hippocampus after 5 days or 14 days of treatment with vehicle or tesofensine. Data are presented as mean ± SEM (n = 8) of the number of cell or cell clusters per section. ^* P < 0.05, Student's t-test.

EXAMPLES

The invention is further illustrated with reference to the following examples, which are not intended to be in any way limiting to the scope of the invention as claimed.

Example 1

Experimental

To examine the effect of 2,3-disubstituted tropanes in view of neuroprotection of neuroprogenitor proliferation, mice have been treated for 2 weeks with 3 mg/kg of the compound of formula III (tesofensine). One gene that codes for a protein with neuroprotective features is BDNF, belonging to neurotrophins and affecting neuronal survival, - differentiation and synaptic plasticity. As a marker for neuroproliferation, cyclin D2 was selected, a cell cycle gene (protein) that may contribute to progenitor cell proliferation.

Results After 2 weeks of treatment the mRNA levels in the entorhinal cortex were increased by 83% (p=0.084) and 63% (p=0.061) for BDNF and cyclin D2. These results provided evidence that 2,3-disubstituted tropanes may modulate cerebral gene expression, thereby, leading to neuroprotection and induction of progenitor cell proliferation. Example 2

Experimental

In another set of experiments adult male Wistar rats (n = 8 per group) were 5 treated with daily oral administration of the compound of formula III (tesofensine) at a dose of 3 mg/kg for either 5 or 14 days. The dose of tesofensine (as citrate salt) was 3 mg/kg p.o., since this dose has been shown to be active in other in-vivo models (Thatte, Current Opinion in Investigational Drugs 2001 2 1592-1594). Twenty-four hours after the last treatment, animals were anaesthetized and perfused with ringer

10 solution and the brains were removed. Each brain was divided into two hemispheres. One hemisphere was immediately frozen in crushed dry-ice and kept at -80 ⁰C for in situ hybridisation. The other hemisphere was were native frozen under cryoprotection with TissueTek in methylbutane (pre-cooled in liquid nitrogen) and then stored at -70⁰C until cryosectioning for Ki-67/NeuroD immunohistochemistry.

15 Twelve-μm serial coronal sections of the hippocampal formation were hybridized for Arc (targeting bases 789-839; NM 019361 ), BDNF (targeting bases 585-630; NM 012513), and synaptophysin (targeting bases 143-187; NM 012664) genes were used (DNA Technology, Aarhus, Denmark) (Mikkelsen et al., MoI. Brain Res. 1994 23 317-322).

20 For analyzing the proteins of interest in the hippocampus, consecutive parasagittal sections from 0.9 mm lateral were rehydrated in PBS 3 x 5 min at room temperature. Unspecific protein binding sites were blocked with PBS containing 3 % (w/v) BSA, 0.1 % (w/v) NaN₃ for 1 h and directly incubated with primary antisera overnight at 4°C according to earlier protocols (Rosenbrock et al, Brain Res. (2005)

25 1040, 55-63).

For quantification of Ki-67 and NeuroD immunopositve cells in the hippocampus, 6 sections per animal with 24 μm space in between were used for immunohistochemistry. After digitizing the images, immunopositive NeuroD cells as well as Ki-67 immunopositive cells and cell clusters were automatically calculated in

30 the region of interest using Halcon imaging software. The region of interest consisted of the subgranular zone and the hilus of the dentate gyrus. The mean of the 6 values derived from 6 slices per animal was used for further statistical analysis regarding group comparisons.

Quantitative data are presented as mean ± SEM calculated from 8 animals

35 per group. The quantitative data from in-situ hybridization and immunofluorescence stainings, comparisons between control and compound-treated groups were performed by Student's t-test. Results

Effect of sub-chronic (5 days) and chronic (14 days) treatment with tesofensine on the expression of different markers in the hippocampus was examined. Using in situ hybridization, densitometric analysis on X-ray films was carried out in the granular cell layer and the pyramidal cell layer as well as in the parietal cortex. The influence of tesofensine on the expression of BDNF mRNA and Arc mRNA is shown in the representative autoradiogram in Fig. 1. The quantification of changes observed after sub-chronic and chronic treatment with tesofensine is presented in Fig. 2.

Treatment with tesofensine for 5 days had no effect on BDNF expression in the granular cell layer and the CA3 (Fig. 2A, B). A significant increase in BDNF gene expression in the CA3 region was observed after chronic tesofensine treatment (Fig. 2A, 36 %, p<0.05), but not in the granular cell layer (Fig. 2B). The induction of Arc gene expression was significantly increased in the CA1 region after chronic treatment with tesofensine (Fig. 2C, 66 %, P<0.05). No changes in Arc mRNA levels were observed in the granular cell layer (Fig. 1 ). In the parietal cortex, tesofensine produced a significant reduction of Arc mRNA expression compared to vehicle after 5 days of treatment (38 % reduction, p<0.05) (Fig. 2D), but no change (P < 0.07) after 14 days of treatment (Fig. 2D). Sub-chronic and chronic tesofensine treatment had no significant effect on the expression of synaptophysin mRNA in either the granular cell layer or in the CA1 (not shown).

As illustrated in Fig. 3, the Ki-67- and NeuroD-positive cells were accumulating in the subgranular cell layer. Dual-staining of NeuroD-positive cells with neuronal (NeuN), glial (GFAP), granulocyte (CD11 b), or proliferative (Ki-67) markers revealed no co-localisation indicating that NeuroD is present in non-mature neurons (Figs. 3A-D). In particular, it is noted that NeuroD-positive cells are distinct from those positive for Ki-67 (Fig. 3C).

Treatment of rats with tesofensine for 5 days led only to a slight, but nonsignificant increase in the subgranular zone of the dentate gyrus, respectively in the number of progenitor cell proliferation (Ki-67 cells: 14%, Ki-67 cell cluster: 16%) and immature neurons (NeuroD cells: 19%), respectively (Fig. 4). However, treatment with tesofensine for 14 days caused a significant increase of the number of Ki-67 cells (37%; Fig. 4A). An increase in number of Ki-67 positive clusters (22%; Fig. 4B) was observed after chronic tesofensine treatment, but these changes did not reach significance. By contrast, the number of NeuroD cells was significantly higher after tesofensine treatment (23%; Fig. 4C).

Claims

1. A method for treatment of a mammal suffering from a disease associated with cerebral neuronal degradation and/or for treatment of a mammal that profits from cerebral neuroprotection due to the danger of cerebral neurodegeneration, in particular in a stage of the disease in that typical symptoms have not manifested, the method comprising administering to said mammal in need of treatment an effective amount of a monoamine neurotransmitter re-uptake inhibitor comprising a 2,3-disubstituted tropane moiety optionally in the form of its physiologically acceptable acid addition salts.

2. A method according to claim 1 , wherein the method induces cerebral progenitor proliferation and/or ameliorates the cerebral synaptic plasticity and/or counteracts the loss of neuronal activity and/or counteracts the loss of synaptic activity.

3. A method according to claims 1 or 2, wherein the method is for treating Alzheimer's disease, in particular in a stage in that no symptoms of the disease have manifested.

4. A method according to claims 1 or 2, wherein the method is for treating

Parkinson's disease, in particular in a stage where no symptoms of the disease have manifested.

5. A method according to any of the preceding claims, wherein the method is for prophylactic treatment.

6. A method according to any of the preceding claims 1 to 4, wherein the method is to decelerate the progression of the disease.

7. A method according to any of the preceding claims, wherein said monoamine neurotransmitter re-uptake inhibitor is a compound of formula (II)

wherein R¹ represents a hydrogen atom or a C_h alky! group;

R² represents a halogen atom or a CF₃ or cyano group;

R³ represents a hydrogen atom or a C_h alky! or Cs-β-cycloalkyl-d-s-alkyl group; and m is 0 or an integer from 1 to 3.

8. A method according to any of the preceding claims, wherein said monoamine neurotransmitter re-uptake inhibitor is the compound of formula (III) or (IV)

9. Use of a monoamine neurotransmitter re-uptake inhibitor comprising a 2,3- disubstituted tropane moiety or a physiologically acceptable acid addition salt thereof according to any of claims 7 or 8 for the preparation of a medicament for a treatment as outlined in any of claims 1 to 6.