Inclusion Criteria:

• Presence of all 3 of the cardinal features of Parkinson disease (resting tremor, bradykinesia and rigidity). The clinical signs must be asymmetric.
• The diagnosis of Parkinson disease within 5 years prior to the Screening Visit.
• Age 30 or older.
• Female subjects must not be of childbearing potential or must use an approved form of contraception for the duration of the trial.

Exclusion Criteria:

• Use of any Parkinson disease medication within 60 days prior to the Baseline Visit.
• Duration of previous use of symptomatic medication for Parkinson disease cannot exceed 90 days such as levodopa, dopaminergic agonists (including ropinirole, pramipexole, pergolide, cabergoline, and the rotigotine transdermal system), selegiline, rasagiline, amantadine, and anticholinergic agents.
• Parkinsonism due to drugs including neuroleptics, alphamethyldopa, reserpine, metoclopramide, valproic acid.
• Use of antioxidants (such as selegiline, rasagiline, vitamins E and C), additional supplemental vitamins or minerals, regular use of neuroleptics, chloramphenicol, valproic acid, warfarin.
• Other parkinsonian disorders.
• Modified Hoehn and Yahr score of 3 or greater at Screening Visit or Baseline Visit.
• UPDRS tremor score of 3 or greater at Screening Visit or Baseline Visit.
• Mini-Mental State Examination (MMSE) score of 25 or less.
• History of stroke.
• Disability sufficient to require treatment with dopaminergic medication or anticipated need for dopaminergic medication within next 3 months.
• Other serious illness, including psychiatric illness.
• Patients with active cardiovascular, peripheral vascular or cerebrovascular disease within the past year.
• Clinically serious abnormalities in the Screening Visit laboratory studies or electrocardiogram.
• Use of methylphenidate, cinnarizine, reserpine, amphetamine or a MAO-A inhibitor within 6 months prior to the Baseline Visit.
• Unstable dose of CNS active therapies.
• Use of appetite suppressants within 60 days prior to the Baseline Visit.
• History of active epilepsy within the last 5 years.
• Revised Hamilton Rating Scale for Depression of 11 or greater.
• Participation in other drug studies or use of other investigational drugs within 30 days prior to Screening Visit.
• History of electroconvulsive therapy.
• History of any brain surgery for Parkinson disease.
• History of structural brain disease such as prior trauma causing damage detected on a CT scan or MRI, hydrocephalus, or prior brain neoplasms.