Adenosine A2A receptor antagonist istradefylline reduces daily OFF time in Parkinson's disease

Background: We evaluated the efficacy and safety of istradefylline, a selective adenosine A(2A) receptor antagonist administered as adjunctive treatment to levodopa for 12 weeks in a double-blind manner in Parkinson's disease patients with motor complications in Japan. Methods: A total of 373 subjects were randomized to receive placebo (n=126), istradefylline 20 mg/day (n=123), or istradefylline 40 mg/day (n=124). The primary efficacy variable was the change in daily OFF time. Other secondary variables were also evaluated. Results: The change in daily OFF time was significantly reduced in the istradefylline 20 mg/day (-0.99 hours, P=.003) and istradefylline 40 mg/day (-0.96 hours, P=.003) groups compared with the placebo group (-0.23 hours). The most common adverse event was dyskinesia (placebo, 4.0%; istradefylline 20 mg/day, 13.0%; istradefylline 40 mg/day, 12.1%). Conclusions: Istradefylline reduced daily OFF time and was well tolerated in Japanese PD patients with motor complications on levodopa treatment. (c) 2013 Movement Disorder Society