Effectiveness and Safety of Perampanel in Refractory Focal Epilepsy: Real-World Evidence From a Chinese Cohort.

OBJECTIVE: To evaluate the effectiveness and safety of perampanel (PER) as an add-on treatment in patients with refractory focal epilepsy. METHODS: This single-center, retrospective observational study consecutively enrolled patients with refractory focal epilepsy who initiated PER as adjunctive therapy between September 2020 and October 2021. The primary outcomes included PER effectiveness (≥ 50% seizure reduction), treatment retention rates, and adverse event (AE) profiles, systematically evaluated at 3-, 6-, and 12-month follow-up intervals. RESULTS: This study included 190 patients (median age 27 years; 51.6% female). At 3/6/12-month follow-ups, response rates were 65.5%/64.9%/66.1%, seizure-free rates 26.2%/26.2%/26.8%, and retention rates 88.4%/69.0%/66.8%, respectively. Logistic regression analysis indicated that females had a lower response rate (OR = 0.38, 95% CI = 0.20.74, p = 0.005). Responders had a higher PER dose (≥ 6 mg) than nonresponders at all follow-ups. Patients receiving late add-on PER treatment had significantly higher response and seizure-free rate than those receiving early add-on therapy. AEs were reported in 41.1% of patients, mostly mild to moderate in severity. The most frequent AEs were dizziness (26.3%), somnolence (13.0%), and psychiatric symptoms (12.11%). Additionally, patients aged ≥ 18 years had a lower risk of AEs (OR = 0.41, 95% CI: 0.19-0.88, p = 0.023). CONCLUSIONS: PER demonstrated clinically meaningful efficacy and acceptable safety in refractory focal epilepsy, with sustained response rates and seizure freedom over 12 months. Male gender, higher doses, and late add-on use predicted better outcomes, while adults experienced fewer adverse events. These real-world findings support PER's role in treatment-resistant cases.