Optimized use of safinamide as an add-on therapy in Asian patients with Parkinson's disease: a narrative review and expert opinion.

Parkinson's disease (PD) imposes a large burden on Asian countries and threatens to grow rapidly as Asian populations age. PD phenotypes in Asian patients differ from those reported in the West, yet management generally follows a similar approach. Levodopa (l-dopa) is a mainstay of therapy and is typically followed by the addition of a catechol-O-methyltransferase inhibitor or a monoamine oxidase-B (MAO-B) inhibitor to address the wearing-off effect. There is little guidance on switching between MAO-B inhibitors or other adjunct therapies that consider the newer evidence for safinamide as an add-on PD therapy in Asian patients. Therefore, a group of PD experts in Asia evaluated the evidence supporting safinamide for the treatment of PD with a focus on integrating this treatment option into local clinical practice. A narrative review was conducted to identify supportive evidence for the formulation of summary statements on key topics. The efficacy and safety of safinamide added to l-dopa in Asian patients with PD are supported by both clinical trials and observational data, including two randomized trials enrolling exclusively Asian patients (n = 406; n = 307) and an Asian subpopulation analysis from another randomized trial (n = 173). Safinamide reduces wear-off duration and has beneficial effects on motor symptoms of PD, with good tolerability outcomes. Safinamide may also have beneficial effects on non-motor symptoms of PD such as urinary symptoms, apathy and sleep disturbances, and it is a suitable treatment for older patients. Overall, safinamide is an effective and well-tolerated treatment for the wear-off effect of l-dopa in Asian patients and, during long-term treatment, might reduce the risk of dyskinesia in patients without pre-existing dyskinesia. Additional research is needed to better understand the role of safinamide for patients with fluctuating pain, the dose-effect relationship of safinamide in Asian patients and the efficacy of safinamide in Asian patients with early-onset PD.