Effects of Safinamide on Pain in Fluctuating Parkinson's Disease Patients: A Post-Hoc Analysis

Pain, a frequent non-motor symptom in Parkinson's Disease (PD), significantly impacts on quality of life. Safinamide is a new drug with dopaminergic and non-dopaminergic properties, approved in Europe as adjunct therapy to levodopa for the treatment of fluctuating PD patients. Results from two 24-month, double-blind, placebo-controlled studies demonstrated that safinamide has positive effects on both motor functions and quality of life in PD patients.

To investigate the effects of safinamide on pain management in PD patients with motor fluctuations using pooled data from studies 016 and SETTLE.

This post-hoc analysis evaluated the reduction of concomitant pain treatments and the changes in the scores of the items related to pain of the Parkinson's Disease Quality of Life Questionnaire (PDQ-39). A path analysis was performed in order to examine direct and indirect associations between safinamide and PDQ-39 pain-related items assessed after 6-months of treatment.

The percentage of patients with no pain treatments at the end of the trials was significantly lower in the safinamide group compared to the placebo group. Safinamide 100 mg/day significantly reduced on average the individual use of pain treatments by ≈24% and significantly improved two out of three PDQ-39 pain-related items of the "Bodily discomfort" domain.Path analysis showed that the direct effect of safinamide on pain accounted for about 80% of the total effect.

These results suggest that safinamide may have a positive effect on pain, one of the most underestimated non-motor symptoms. Prospective studies are warranted to investigate this potential benefit.