To report long-term (1-year) safety and efficacy data of adjunctive perampanel in pediatric patients from Study 311.

This analysis included cumulative data from all enrolled patients in the Core Study (23 weeks of treatment) and Extension Phase A (52 weeks of treatment). Assessments included monitoring of treatment-emergent adverse events (TEAEs), median percent change in seizure frequency per 28 days from baseline, and 50% responder and seizure-freedom rates.

Of 180 patients enrolled in the Core Study (POS, n=149; SGS, n=54; PGTCS, n=31), 136 patients entered Extension A. Of these, 14 patients discontinued Extension A; most common primary reasons for discontinuation were adverse events (3.7%) and inadequate therapeutic effect (2.9%). For all patients, mean (standard deviation [SD]) time since diagnosis was 5.7 (2.9) years and mean (SD) duration of exposure was 41.5 (17.3) weeks. During baseline, 55.6% of patients received two concomitant ASMs. TEAEs were reported in 162 (90.0%) patients; somnolence was the most commonly reported (27.2%). Median percent reductions in POS, SGS, and PGTCS frequencies at Weeks 1–13 were 43.0%, 57.9%, and 79.3%, respectively; these were maintained at Weeks 40–52: 69.4%, 73.8%, and 100.0%, respectively. Seizure-freedom rates for POS, SGS, and PGTCS at Weeks 40–52 were: 13.0%, 24.4%, and 38.5%, respectively.

Long-term (1-year) adjunctive perampanel is generally safe, well tolerated, and efficacious in pediatric patients aged 4 to <12 years with POS (with or without SGS) or PGTCS.

Funding: Eisai Inc.