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Adenosine a2a receptor antagonists for the treatment of extra-pyramidal syndrome and other movement disorders

Adenosine a2a receptor antagonists for the treatment of extra-pyramidal syndrome and other movement disorders description/claims

This application claims the benefit of U.S. Provisional Application 60/435,321, filed Dec. 19, 2002.

The present invention relates to the use of adenosine A2a receptor antagonists for the treatment of a variety of neurological syndromes involving the extra-pyramidal motor system (i.e. Extra-Pyramidal Syndrome) that occur following the acute and chronic use of almost all antipsychotic drugs. The invention also relates to the use of adenosine A2a receptor antagonists for the treatment of other abnormal movement disorders such as restless leg syndrome (RLS) and periodic limb movement in sleep (PLMS).

Extra-Pyramidal Syndrome (EPS) is a collective term for a series of adverse neurological reactions associated with the use of antipsychotic drugs. There are six different categories of EPS-related neurological syndromes of which four, dystonia, akathisia, pseudoparkinsonism (parkinsonian syndrome), and tardive dyskinesia, are particularly prevalent in patients taking antipsychotic medication. Dystonia is a painful spasm of the muscle groups of, in particular, the neck, jaw, back, pharynx, and larynx. It is most common in young males being treated with antipsychotic drugs, but can also be associated with the use of cocaine, tricyclic antidepressants, lithium and anticonvulsants such as phenyloin and carbamazepine. Pseudoparkinsonism manifests itself as akinesia (rigidity, stiffness and slow voluntary motion, stooped, shuffling walk) and tremor and these symptoms develop within weeks or months after initiation of therapy. Akathisia manifests itself as strong, subjective inner feelings of distress or discomfort characterized by motor restlessness. Often mistaken for agitation or anxiety, this common syndrome is frequently under-diagnosed and is the least responsive to treatment. Tardive dyskinesia is a late-appearing syndrome associated with chronic use of neuroleptic drugs. It occurs more frequently in older patients and is characterized by stereotypical, repetitive, involuntary, quick choreiform movements of the face, eyelids, mouth, tongue, extremities and trunk.

EPS is more prevalent with the use of typical antipsychotic agents but has also been reported with the use of atypical agents. Typical antipsychotics include loxapine, haloperidol, chlorpromazine, prochlorperazine and thiothixene. Atypical antipsychotics include clozapine, olanzapine, loxapine, quetiapine, ziprasidone and risperidone.

Akathisia is also a characteristic of RLS and PLMS, as well as PLMD (periodic leg (or limb) movement disorder). RLS is a common disorder that causes patients to have an irresistible and unpleasant desire to move their legs; it usually manifests during periods of inactivity and/or at night, and can disturb sleep. Patients who do not have the typical RLS symptoms, but who do exhibit periodic leg movements that adversely impact sleep, are diagnosed with PLMS. Treatments for RLS and PLMS have included levodopa/carbidopa, levodopa/benserazide, dopamine agonists such as pramipexole and ropinerole, benzodiazepines, opioids, anticonvulsants and iron (ferrous sulfate). RLS and PLMS have been extensively described in the literature, for example by Saletu et al, Neuropsvchobiology, 41, 4 (2000), p. 190-9.

The purine nucleotide, adenosine, is known to be an endogenous modulator of a number of physiological functions in the central (CNS) and peripheral nervous systems.

Adenosine exerts its biological actions through a class of membrane specific receptors which belong to the super family of receptors coupled with G proteins. Biochemical and pharmacological studies, together with advances in molecular biology, have allowed the identification of at least four subtypes of adenosine receptors: A1, A2a, A2b and A3. Analogs of adenosine able to interact as antagonists with the A1, A2a, A2b and A3 receptors have also been identified.

In the CNS, data has shown that A2a receptors are present in high density in the basal ganglia, known to be important in the control of fine motor movement. Moreover, selective antagonists for the A2a receptor are of pharmacological interest because of their demonstrated efficacy in reducing motor impairment thereby improving function in neurodegenerative diseases such as Parkinson's disease and related movement disorders (e.g. Huntington's Disease). A2a antagonists appear to demonstrate a reduced side-effect liability (e.g. no dyskinesia) compared to current dopaminergic therapies resulting in an improved therapeutic index. A2a antagonists may also have antidepressant properties and stimulate cognitive functions. Some xanthine-related compounds have been found to be A1 receptor selective antagonists, and xanthine and non-xanthine compounds have been found to have high A2a affinity with varying decrees of A2a vs. A1 selectivity. Adenosine A2a receptor antagonists have been disclosed previously, for example in WO 95/01356 and U.S. Pat. No. 6,630,475.

This invention relates to a method for the treatment or prevention of Extra-Pyramidal Syndrome (e.g., dystonia, akathisia, pseudoparkinsonism and tardive dyskinesia) comprising administering a therapeutically effective amount of an adenosine A2a receptor antagonist to a patient in need thereof. In particular, this method is for the treatment or prevention of EPS in patients treated with an antipsychotic agent that has the side effect of inducing EPS. The adenosine A2a receptor antagonist can be administered after the symptoms of EPS have manifested, or an adenosine A2a receptor antagonist can be administered at the onset of administering an antipsychotic agent in order to prevent EPS from occurring. The invention, therefore, also includes a method of treating or preventing EPS induced by an antipsychotic agent comprising administering a combination of an antipsychotic agent and an adenosine A2a antagonist to a patient in need thereof. More particularly, the invention relates to the method of using of certain adenosine A2a antagonists for the monotherapy or the combined therapy.

The invention also relates to the treatment of primary (idiopathic) dystonia, and to the treatment or prevention of dystonia in patients who exhibit dystonia as a result of treatment with a tricyclic antidepressant, lithium or an anticonvulsant, or who have used cocaine, comprising administering a therapeutically effective amount of an adenosine A2a receptor antagonist to a patient in need thereof. When dystonia is caused by treatment with a tricyclic antidepressant, lithium or an anticonvulsant, the adenosine A2a receptor antagonist can be administered after the symptoms of dystonia have manifested, or an adenosine A2a receptor antagonist can be administered at the onset of administering a tricyclic antidepressant, lithium or an anticonvulsant in order to prevent dystonia from occurring. The invention, therefore, also includes a method of treating or preventing dystonia induced by a tricyclic antidepressant, lithium or an anticonvulsant comprising administering a combination of an adenosine A2a antagonist and a tricyclic antidepressant, lithium or an anticonvulsant to a patient in need thereof.

The invention also relates to the treatment of RLS or PLMS, comprising administering to a patient in need thereof a therapeutically effective amount of an adenosine A2a receptor antagonist. The invention also comprises a method of treating RLS or PLMS comprising administering a combination of an adenosine A2a antagonist with another agent useful in treating RLS or PLMS, such as levodopa/carbidopa, levodopa/benserazide, a dopamine agonist, a benzodiazepine, an opioid, an anticonvulsant or iron, to a patient in need thereof.

In another aspect, this invention relates to a kit comprising, in separate containers in a single package, pharmaceutical compositions for use in combination to treat or prevent EPS caused by treatment with antipsychotic agent, wherein one container comprises a pharmaceutical composition comprising an effective amount of an adenosine A2a receptor antagonist in a pharmaceutically acceptable carrier, and wherein a separate container comprises a pharmaceutical composition comprising an effective amount of an antipsychotic agent.

In another aspect, this invention relates to a kit comprising, in separate containers in a single package, pharmaceutical compositions for use in combination to treat or prevent dystonia caused by treatment with a tricyclic antidepressant, lithium or an anticonvulsant, wherein one container comprises a pharmaceutical composition comprising an effective amount of an adenosine A2a receptor antagonist in a pharmaceutically acceptable carrier, and wherein a separate container comprises a pharmaceutical composition comprising an effective amount of a tricyclic antidepressant, lithium or an anticonvulsant.

In another aspect, this invention relates to a kit comprising, in separate containers in a single package, pharmaceutical compositions for use in combination to treat RLS or PLMS, wherein one container comprises a pharmaceutical composition comprising an effective amount of an adenosine A2a receptor antagonist in a pharmaceutically acceptable carrier, and wherein a separate container comprises a pharmaceutical composition comprising an effective amount of levodopa/carbidopa, levodopa/benserazide, a dopamine agonist, a benzodiazepine, an opioid, an anticonvulsant or iron.

The invention also relates to the use of an adenosine A2a receptor antagonist for the preparation of a medicament for treating or preventing EPS, dystonia, RLS or PLMS, alone or in combination with the other agents discussed above.

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