Long-term safety and efficacy of opicapone in Japanese Parkinson’s patients with motor fluctuations

The double-blind part of the COMFORT-PD (COMt-inhibitor Findings from Opicapone Repeated Treatment for Parkinson’s Disease) study in Japanese levodopa-treated patients with Parkinson’s disease and motor fluctuations found that both opicapone 25 and 50 mg were significantly more effective than placebo. This 52-week open-label extension study evaluated the long-term safety and efficacy of opicapone 50 mg tablets in patients who completed the double-blind part of the COMFORT-PD study. Safety was monitored via adverse events, laboratory testing, and physical, cardiovascular and neurological examinations. Efficacy was primarily assessed by change in OFF-time. Secondary efficacy measures included: ON-time, percentage of OFF/ON-time responders, other outcomes from the double-blind part. 391/437 patients were transferred to the open-label extension period and included in the safety analysis set (full analysis set, n = 387; open-label completers, n = 316). Adverse events were frequently reported (n = 338, 86.4%), but < 50% were considered drug-related (39.9%) and few were considered serious (2.6%) or led to discontinuation (2.8%). Decreased OFF-time was consistently observed over the open-label period regardless of initial randomization. Change [LSM (SE)] in OFF-time from the open-label baseline to the last visit showed a persistent effect in patients initially randomized to opicapone 25 mg [− 0.37 (0.20) h, P = 0.0689] and opicapone 50 mg [− 0.07 (0.21) h, P = 0.6913] whereas opicapone 50 mg led to a statistically significant reduction in the previous placebo group [− 1.26 (0.19) h, P < 0.05]. Once-daily opicapone 50 mg was generally well tolerated and consistently reduced OFF-time over 52 weeks in Japanese levodopa-treated patients with motor fluctuations. Trial registration JapicCTI-153112; date of registration: December 25, 2015. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s00702-021-02315-1.