Pain Improvement in Parkinson's Disease Patients Treated with Safinamide: Results from the SAFINONMOTOR Study

Background and objective: Pain is a frequent and disabling symptom in Parkinson's disease (PD) patients. Our aim was to analyze the effectiveness of safinamide on pain in PD patients from the SAFINONMOTOR (an open-label study of the effectiveness of SAFInamide on NON-MOTOR symptoms in Parkinson's disease patients) study. Material and Methods: SAFINONMOTOR is a prospective open-label single-arm study conducted in five centers from Spain. In this analysis, a secondary objective of the study, the score in the KPPS (King's Parkinson's Disease Pain Scale) at V1 (baseline) and V4 (6 months +/- 1 month) were compared. Wilcoxon's rank sum test was performed to test the changes from V1 to V4. Results: Forty-four (88%) out of 50 PD patients (age 68.5 +/- 9.12 years; 58% women; 6.4 +/- 5.1 years from diagnosis) completed the study. The KPPS total score was reduced by 43.6% (from 40.04 +/- 36.18 in V1 to 22.60 +/- 21.42 in V4; p < 0.0001). By domains, improvement was observed in musculoskeletal (-35.9%; p = 0.009), fluctuation-related (-51.7%; p = 0.020), nocturnal (-46.1%; p = 0.001), discoloration and/or edema/swelling (-50.4%; p = 0.009) and radicular pain (-40.1%; p = 0.048). A total of 21 adverse events in 11 patients (22%) were reported, five being severe, but not related to safinamide. Conclusion: Safinamide is well tolerated and improves pain in PD patients at 6 months. Future studies are necessary to analyze the possible beneficial effect of safinamide on pain in PD patients.