Study of the Effect of SR57667B on the Progression of Symptoms in Patients With Parkinson's Disease

Inclusion Criteria: * Male or female outpatients. * Age \>=35 years at screening.· * Diagnosis of Parkinson's syndrome, on at least two of the three key Parkinson's symptoms, i.e. resting tremor, bradykinesia and rigidity. * Duration of the disease of less than 3 years since diagnosis· * Modified Hoehn and Yahr stage \<= 2.5. * Untreated patients. * Generally healthy and ambulatory. * Patient has given his informed written consent and is capable of following study procedures. Exclusion Criteria: * Any indication of forms of parkinsonism other than PD. * Severe resting tremor. * Presence of either dyskinesia, fluctuations, or loss of postural reflexes· * Treatment with L-Dopa, dopamine agonist, amantadine, anticholinergics, catechol-o-methyltransferase (COMT ) inhibitors, selegiline, dopamine receptor antagonists, catecholamine depleters, indirect dopamine agonists or alphamethyldopa. * Electroconvulsive therapy (ECT). * Use of CYP3A4 strong, and moderate inducers or inhibitors. * Participation in another clinical trial with an investigational drug within two months prior to randomization. * Dementia, uncontrolled depression, psychotic disorder. * History of substance-related disorders including alcohol or other substance use disorders. * Females of child bearing potential. * Evidence (detected by history, physical examination and/or laboratory/ECG tests) of any clinically significant or unstable medical disorder that could interfere with the patient's participation in the clinical trial; interfere with the absorption, metabolism or excretion of the study medication; or interfere with the evaluation of the study drug. * Alterations of laboratory tests or ECG findings of potential clinical significance.