Long‐term safety and efficacy of preladenant in subjects with fluctuating Parkinson's disease

Background Preladenant is a selective adenosine A 2A receptor antagonist under investigation for Parkinson's disease treatment. Methods A phase 2 36‐week open‐label follow‐up of a double‐blind study using preladenant 5 mg twice a day as a levodopa adjunct in 140 subjects with fluctuating Parkinson's disease was conducted. The primary end point was adverse event (AE) assessment. Secondary (efficacy) analyses included hours/day spent in OFF and ON states and dyskinesia prevalence/severity. Results The 36‐week open‐label phase was completed by 106 of 140 subjects (76%). AE‐related treatment discontinuations occurred in 19 subjects (14%). Treatment‐emergent AEs, reported by ≥15% of subjects, were dyskinesia (33%) and constipation (19%). Preladenant 5 mg twice a day provided OFF time reductions (1.4–1.9 hours/day) and ON time increases (1.2–1.5 hours/day) throughout the 36‐week treatment relative to the baseline of the double‐blind study. Conclusions Long‐term preladenant treatment (5 mg twice a day) was generally well tolerated and provided sustained OFF time reductions and ON time increases. © 2013 Movement Disorder Society