Safety and efficacy of istradefylline in Parkinson's disease patients with and without pre-existing dyskinesia: Pooled analysis of 8 randomized controlled trials.

Objectives: Evaluate the efficacy of istradefylline in people with Parkinson's disease with motor fluctuations, with and without dyskinesia, and characterize potential predictors for treatment-emergent dyskinesia with istradefylline.

Methods: Pooled analysis of 8 phase 2b/3 trials of istradefylline (20 or 40mg/day) versus placebo.

Results: Data from 2719 patients, including 56% with baseline dyskinesia, were analyzed post-hoc. The presence of baseline dyskinesia did not affect mean reductions in OFF-time, increases in ON-time without troublesome dyskinesia, or improvements in Unified Parkinson's Disease Rating Scale motor scores associated with istradefylline treatment. Dyskinesia was reported by 17% of istradefylline-treated patients, with higher rates for women (21%), patients with BMI <18.5 kg/m2 (22%), and patients treated with COMT inhibitors plus dopamine agonists (22%) and MAO-B inhibitors (25%).

Conclusion: Istradefylline treatment resulted in greater reductions in total OFF hours/day and increases in ON-time without troublesome dyskinesia versus placebo regardless of the presence or absence of pre-existing dyskinesia.