Long-term safety and efficacy of safinamide as add-on therapy in levodopa-treated Japanese patients with Parkinson's disease with wearing-off: Results of an open-label study

Abstract Introduction Safinamide, a selective, reversible monoamine oxidase B inhibitor with a sodium channel inhibitory effect, improves symptoms in advanced Parkinson's disease (PD). This study aimed to confirm the long-term safety and efficacy of safinamide in Japanese PD patients with wearing-off. Methods Japanese PD patients aged ≥30 years with wearing-off were eligible. The primary efficacy endpoint was change from baseline in the mean daily ON-time without troublesome dyskinesias at 52 weeks of treatment. Other efficacy endpoints included changes from baseline in mean daily OFF-time and unified Parkinson's disease rating scale (UPDRS) and PDQ-39 scores. Results In total, 203 patients entered the study, and 142 completed the 52-week treatment. Adverse events (AEs) occurred in 78.3% of patients, with nasopharyngitis (20.7%) and dyskinesias (17.7%) as the most common; serious AEs occurred in 17.2%, causing discontinuation in 10.8%. At Week 52, the mean daily ON-time without troublesome dyskinesias increased from baseline by 1.42 h. Change from baseline in mean daily OFF-time was −1.40 h, and that in the UPDRS Part III score in the ON-phase was −6.20. Conclusions As adjunctive treatment with levodopa, safinamide was safe, well tolerated, and effective in improving ON-time and other PD symptoms at 52 weeks.