Background We report data from three Phase IV, observational studies (Studies 506 [US; NCT03208660], 508 [India; NCT03836924] and 501 [Italy; NCT04257604]), which assessed real-world safety and efficacy of adjunctive perampanel across different regions.

Methods Study 506 included patients with any seizure type. Studies 508/501 included patients with focal- onset seizures. Endpoints included: retention rate (Studies 506/501), median percent reduction in seizure frequency/28 days, seizure-freedom rates and safety.

Results In Study 506, the 12-month retention rate was 58.5% (n=876/1498). At Months 10–12, the median percent reduction in seizure frequency/28 days was 75.0% (n=123) and the seizure-freedom rate was 30.9% (n=38/123). In Study 508, the 6-month median percent reduction in seizure frequency/28 days was 100.0% (n=174) and seizure-freedom rate was 49.4% (n=86/174). In Study 501, the 6-month median percent reduction in seizure frequency/28 days, retention rate and seizure-freedom rate were 55.4% (n=198), 72.6% (n=170/234) and 18.0% (n=36/200), respectively. Treatment-emergent adverse events occurred in 704/1703 (41.3%; Study 506), 36/199 (18.1%; Study 508) and 132/234 (56.4%; Study 501) patients; the most common was dizziness/vertigo.

Conclusions Perampanel is efficacious and well tolerated during real-world use regardless of geographi- cal region; no unexpected safety signals emerged.

Funding Eisai Inc., Eisai Pharmaceuticals India Pvt., Ltd., and Eisai s.r.l.