Perampanel was up-titrated from 2 mg/day (weekly 2-mg increments) to ≤12 mg/day (POS; 6-week titration; 13-week maintenance) or ≤8 mg/day (PGTCS; 4-week titration; 17-week maintenance). TEAE rates were analyzed by treatment period (Titration, Pre-steady-state, Maintenance) in patients who received perampanel and completed the study.

Overall, 1387 patients were included (≥12–<18 years, n=159 [2 mg, n=20; 4 mg, n=35; 8 mg, n=74; 12 mg, n=30]; ≥18 years, n=1235 [2 mg, n=134; 4 mg, n=282; 8 mg, n=509; 12 mg, n=310]). Total perampanel exposure (subject-months) during Titration–Maintenance for 2, 4, 8, and 12 mg/day in the younger cohort was: 5.0–74.5, 17.5–121.3, 74.0–213.5, and 45.0–73.4, respectively; and in the older cohort was: 33.5–496.1, 141.0–975.1, 509.0–1482.9, and 465.0–759.2, respectively. In both cohorts, overall rates of TEAEs per 100 subject-months were highest during Titration (younger cohort: 35.6–68.6 [range dependent on perampanel dose]; older cohort: 46.1–59.7), lower during Pre-steady-state (younger cohort: 26.7–41.4; older cohort: 26.9–47.7), and at their lowest during Maintenance (younger cohort: 14.0–21.8; older cohort: 13.1–20.8). In general, the most common TEAEs during Titration (dizziness, somnolence, headache) had lower rates during Pre-steady-state and Maintenance in both cohorts.

These data suggest perampanel tolerability may improve as a patient reaches the Maintenance Period, regardless of age.

Funding: Eisai Inc.