Long-term Seizure Freedom with Adjunctive Perampanel in Patients Aged 4–<12 Years with Focal-onset Seizures or Generalized Tonic-clonic Seizures

Background: Perampanel is a once-daily oral anti-seizure medication (ASM) for focal-onset seizures (FOS) and generalized tonic-clonic seizures (GTCS). Long-term seizure-freedom rates with adjunctive perampanel are maintained in adolescent and adult patients (aged ≥12 years) with focal to bilateral tonic-clonic seizures (FBTCS) or GTCS. Here, we assessed if seizure-freedom rates achieved with adjunctive perampanel during the 311 Core Study (NCT02849626) are maintained during long-term treatment in pediatric patients with FOS (with or without FBTCS) or GTCS.

Methods: Seizure-freedom rates (FOS, FBTCS, or GTCS) were assessed in patients who achieved seizure freedom during the Core Study Maintenance Period and then remained seizure free for 6 and/or 12 months (calculated from the start of their seizure-free period). Data were stratified by concomitant enzyme-inducing ASMs (EIASMs) (with or without) and age (4– <7 or 7– <12 years).

Results: For FOS, 13/17 (76.5%) patients remained seizure free for 6 months (with EIASMs, n=3/5 [60.0%]; without EIASMs, n=10/12 [83.3%]; 4– <7 years, n=1/3 [33.3%]; 7– <12 years, n=12/14 [85.7%]) and 6/11 (54.5%) remained seizure free for 12 months (with EIASMs, n=2/5 [40.0%]; without EIASMs, n=4/6 [66.7%]; 4– <7 years, n=0/1; 7– <12 years, n=6/10 [60.0%]). For FBTCS, 3/8 (37.5%) patients remained seizure free for 6 months (with EIASMs, n=0/1; without EIASMs, n=3/7 [42.9%]; 4– <7 years, n=0/3; 7– <12 years, n=3/5 [60.0%]) and 1/5 (20.0%) patient remained seizure free for 12 months (with EIASMs, n=0/1; without EIASMs, n=1/4 [25.0%]; 4– <7 years, n=0/2; 7– <12 years, n=1/3 [33.3%]). For GTCS, 6/10 (60.0%) patients remained seizure free for 6 months (no GTCS seizure-free patients received EIASMs; 4– <7 years, n=1/2 [50.0%]; 7– <12 years, n=5/8 [62.5%]) and 3/7 (42.9%) patients remained seizure free for 12 months (all 7– <12 years, n=3/6 [50.0%]).

Conclusion: Despite small patient numbers, seizure-freedom rates are maintained during long-term (1 year) perampanel treatment in pediatric patients, consistent with analyses in adolescents and adults.

Funding: Eisai Inc.