Studies 307, 335 OLEx, 412, and 342 included patients with FOS. Perampanel was adjunctive (Studies 307/335 OLEx), first add-on (Study 412), monotherapy (Study 342), or provided during routine clinical care (Study 506). Endpoints included changes in seizure frequency, 50% responder and seizure-freedom rates, and seizure-onset rate.

Pooled data from Studies 307 and 335 OLEx (N=71) showed median reduction from baseline in FOS (with/without focal to bilateral tonic-clonic seizures) frequency/28 days of 31.7%, 44.5%, 49.8%, and 69.3% during Years 1, 2, 3, and 4 of treatment, respectively; corresponding 50% responder rates were 24/71 (33.8%), 18/38 (47.4%), 9/19 (47.4%), and 9/14 (64.3%), and seizure-freedom rates were 0/71 (0.0%), 1/38 (2.6%), 1/19 (5.3%), and 0/14 (0.0%). In Study 412 (N=15); 50% responder and seizure-freedom rates were 12/15 (80%) and 9/15 (60%), respectively. In Study 342 (N=23), 12/19 (63.2%) patients were seizure free during 4-mg/day Maintenance; cumulative probability of seizure onset rate at Maintenance Week 26 was 32.0% (95% confidence interval, 15.8, 57.9). In Study 506 (N=75), median reduction from baseline in total seizure frequency/28 days was 59.7% (Months 1–3; n=13), 68.6% (Months 10–12; n=8), and 100.0% (Months 22–24; n=5). 50% responder and seizure-freedom rates for Months 1–3, 10–12, and 22–24 were 7/13 (53.8%) and 4/13 (30.8%); 5/8 (62.5%) and 3/8 (37.5%); and 4/5 (80.0%) and 3/5 (60.0%), respectively.