BACKGROUNDParkinson's Disease (PD) is a common progressive neurodegenerative disorder that leads to an imbalance of various neurotransmitters and affects cognitive, motor and non-motor function. Safinamide inhibits monoamine oxidase B in a highly selective and reversible manner and beyond that has anti-glutamatergic properties, with positive effects on motor and non-motor symptoms. The aim of the study was to obtain data about the effectiveness and tolerability of safinamide under routine clinical practice conditions in unselected patients with Parkinson's disease (PD).METHODSA post-hoc analysis of the German cohort of the European SYNAPSES study (a non-interventional cohort study). Patients were treated with safinamide as an add-on to levodopa and followed-up for 12 months. Analyses were done in the total cohort and in clinically relevant subgroups (patients older than 75 years; with relevant comorbidities; with psychiatric conditions).RESULTS181 PD patients were eligible for analysis. Motor symptoms included bradykinesia (76.8%), rigidity (77.3%), tremor (58.6%), and postural instability (27.1%). Non-motor symptoms were reported in 161 patients (89.0%), mainly psychiatric symptoms (43.1%), sleep disorders (35.9%), fatigue (30.9%), and pain (27.6%). 28.7% of patients were aged 75 years or older, 84.5% had relevant comorbidities, and 38.1% had psychiatric conditions. During treatment, the rate of motor complications decreased from 100.0% to 71.1%. UPDRS scores improved under safinamide, with a clinically important effect in 50% in the total score and 45% in the motor score. The positive effect on motor complications occurred already at the 4-month visit and was maintained over 12 months. At least one adverse event (AE)/adverse drug reaction (ADR) was reported by 62.4%/25.4% of patients, AEs were generally mild or moderate, and completely resolved. Only 5 (1.5%) AEs had a definite relationship to safinamide.CONCLUSIONSThe benefit-risk profile of safinamide was favourable and consistent with the total cohort of the SYNAPSES study. In the subgroups, findings were congruent with the total population, which allows the clinical utilisation of safinamide also in more vulnerable patient groups.