Challenges of Pain in Parkinson's Disease: Results from the <scp>OCEAN</scp> Study

BACKGROUND: Pain is a common non-motor symptom in Parkinson's disease (PD) and is often associated to fluctuations. OBJECTIVE: The OpiCapone Effect on motor fluctuations and pAiN (OCEAN) study evaluated the effect of opicapone on fluctuation-related pain when added to levodopa therapy in PD patients. METHODS: Patients with PD with end-of-dose motor fluctuations and associated pain were randomized to opicapone 50 mg or placebo for 24 weeks. The primary end point was reduction from baseline to week 24 in the King's Parkinson's Disease Pain Scale (KPPS) domain 3. Reductions in KPPS and Movement Disorder Society-sponsored Non-Motor Rating Scale (MDS-NMS) total scores and safety/tolerability were also evaluated. RESULTS: A total of 122 patients were included (opicapone, n = 59; placebo, n = 63). Mean (standard deviation) change from baseline in KPPS domain 3 was -8.8 (6.9) points in the opicapone group versus -9.3 (6.2) points in the placebo group (P = 0.7940). Opicapone resulted in numerically greater reductions versus placebo in KPPS and MDS-NMS total scores and was generally well tolerated. CONCLUSIONS: Opicapone did not reach statistical superiority over placebo, highlighting the complexities of studying pain in PD. © 2026 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.