I-STEP Istradefylline Study of Safety & Treatment Efficacy in Parkinson's Disease

The purpose of this study is to evaluate the safety and efficacy of Istradefylline for reducing the total hours per day of OFF time in patients with moderate to severe PD with motor fluctuations and dyskinesia. Patients who meet the following criteria could be eligible to participate:

  • Male or female, 30 years of age or older at the time of enrollment
  • Diagnosed with idiopathic PD
  • Treatment with levodopa therapy for at least 1 year
  • Taking total daily levodopa dosage of at least 400 mg plus at least 1 adjunctive medication approved to treat PD (Dopamine Agonist, COMT or MAO-B)
  • Subjects who have documented end-of-dose wearing-off and who have experienced levodopa-induced dyskinesia;

The study will enroll approximately 609 patients at 95 sites. Study participation will consist of 7 total visits, 2 screening visits and 5 treatment visits, over a period of about 14 weeks. Patients will be randomized to one of three treatment groups below in a 1:1:1 ratio.

  • Group 1: Study treatment 20 mg/d
  • Group 2: Study treatment 40 mg/d
  • Group 3: Placebo

Study enrollment is currently active. Enrolled patients may be compensated for travel and meals.

If you are interested in knowing more about this clinical trial, please contact:

Study Coordinator