A Study of Istradefylline (KW-6002) for the Treatment of Parkinson's Disease

Parkinson's disease (PD) is a progressive motor disease characterized by bradykinesia or akinesia, rigidity, and resting tremor. Levodopa is still the most widely used treatment for PD, but as the disease progresses the drug tends to become less helpful. This is because of the development of motor response complications such as end-of-dose deterioration or wearing-off, peak dose dyskinesias, and ON-OFF phenomenon. Comparison(s): The safety of 40 mg/d istradefylline and the efficacy for reducing the percentage of OFF time in patients with advanced PD treated with levodopa will be compared to placebo. The safety and efficacy of Entacapone will also be compared to placebo.