Adjunctive perampanel efficacy, safety in epilepsy hold up over long-term assessment

Adjunctive perampanel appears to be safe and effective for long-term treatment of patients with tonic‐clonic seizures, according to a posthoc analysis.

The analysis included patients with focal to bilateral tonic‐clonic seizures (FBTCS; n=720) or generalized tonic‐clonic seizures (GTCS; n=138) aged ≥12 years who participated in four open‐label extension (OLEx) studies. These patients received adjunctive perampanel (up to 12 mg/d) for up to 4 years.

In the FBTCS and GTCS groups, mean ages were 32.5 and 27.9 years, respectively, and 48.9 percent and 57.3 percent were women. Mean cumulative duration of perampanel exposure was 102.3 weeks in the FBTCS group and 83.9 weeks in the GTCS group. Retention rates were 50.0 percent for up to 4 years in the former and 49.2 percent for up to 2 years in the latter.

Across OLEx treatment durations, seizure frequency per 28 days decreased by a median of 66.7 percent in the FBTCS group and by 80.6 percent in the GTCS group. In the former, 59.5 percent, 45.3 percent, and 18.4 percent of the patients achieved 50-percent and 75-percent responses and freedom from seizure, respectively. The corresponding numbers in the GTCS group were 72.5 percent, 51.5 percent, and 16.7 percent.

The beneficial effects persisted for up to 4 years for FBTCS and up to 3 years for GTCS, even when accounting for early dropouts.

Treatment-emergent adverse event (TEAE) rates were the highest during year 1, occurring in 85.3 percent in the FBTCS group and 86.2 percent in the GTCS group; the most common were dizziness and somnolence. Eighty-one (11.3 percent) and 10 (7.2 percent) patients in the respective groups developed serious TEAEs. The reported TEAEs were consistent with the known safety profile of perampanel, and no new safety signals emerged with long‐term treatment.