A 6-month prospective, open-label US observational study found add-on opicapone improved motor and non-motor fluctuations and was generally well tolerated in Parkinson's patients with OFF episodes.

Supports real-world symptomatic efficacy and tolerability of opicapone as a levodopa adjunct—useful for clinical practice and therapeutic positioning but offering limited mechanistic or novel discovery insights for Parkinson's drug development.

INTRODUCTION: This study evaluated treatment outcomes of opicapone when used as add-on to levodopa in US patients with Parkinson's disease (PD) experiencing OFF episodes in clinical settings. METHODS: The prospective, open-label, multicenter, observational OPTI-ON study examined patient characteristics, treatment outcomes, and safety/tolerability of Opicapone over 6 months. Clinician-reported outcomes included the Clinician Global Impression of Change (CGI-C), and Movement Disorder Society-sponsored revision of the Unified Parkinson's Disease Rating Scale (MDS-UPDRS) Parts IA and IV. Patient-reported outcomes included the Patient Global Impression of Change (PGI-C), MDS-UPDRS Parts IB and II, and the novel Patient Global Impression of Severity in ON and OFF states (PGI-S ON and OFF) and Non-motor Fluctuation Assessment (NoMoFa). RESULTS: The completer set included 161 patients (mean age, 66.8 years; PD duration, 7.8 years; fluctuation onset, 3.6 years). 38.0% of patients were 'very much/much improved' on CGI-C; 48.7% and 57.5% showed improvement on MDS-UPDRS Parts IA and IV, respectively; 23.5% of patients rated themselves 'very much/much improved' on PGI-C, and 49.5% and 56.5% reported improvements on MDS-UPDRS Parts IB and II, respectively. On PGI-S ON, the proportions of patients with 'none/very mild' PD symptoms during ON times were maintained, while, on PGI-S OFF, the proportion of patients with 'moderately to extremely severe' PD symptoms during OFF times decreased by 12.7%. NoMoFa Total Score improved in 48.0% of patients. Opicapone was generally well tolerated. CONCLUSIONS: In clinical practice, OPC treatment led to improvements in motor and non-motor fluctuations, quality of OFF episodes, and was generally well tolerated.