Gender Differences in Efficacy and Tolerability of Opicapone in Add on of Levodopa. A Single-Center Retrospective Cohort Study

INTRODUCTION: Opicapone is a peripheral catechol-O-methyltransferase inhibitor (COMT), approved an add on to levodopa in Parkinson's disease (PD) patients with motor fluctuations. We carried out a retrospective cohort study to evaluate gender differences in efficacy and tolerability of opicapone. METHODS: PD patients with motor fluctuations who started opicapone and who were followed up for at least 6 months were retrospectively enrolled. Total daily OFF (at baseline and follow-up), presence or worsening of dyskinesia, or presence of other adverse events (AE) at follow-up, were recorded. RESULTS: Seventy-seven PD patients (51 men; 66.2%) with a disease duration of 11.0 ± 4.2 years were enrolled. At follow-up, a significant reduction of the total daily OFF time was observed in men with PD. Overall, 41.6% of PD patients reported some AEs, of which the presence or worsening of dyskinesia was the most common. Incidence of AEs was significantly higher among women (65.4% versus 29.4%; p-value 0.002) and at multivariate analysis, female sex was significantly associated with the presence of AEs (OR 4.08; 95% CI 1.46-11.4; p-value 0.007); At 6 months 27.3% patients discontinued opicapone and women had significantly higher odds of discontinuation (OR 3.00; p-value 0.04). DISCUSSION: Opicapone is highly effective for the treatment of motor fluctuations. The occurrence of AEs is more frequent among women may be attributed to a higher levodopa bioavailability. To avoid an early discontinuation due to AEs, levodopa dosage should be reduced in women before the introduction of opicapone. CONCLUSION: Our study provides novel insights regarding gender differences in PD treatment.