Abstracts

Rationale: Perampanel is a once-daily oral anti-seizure drug for partial-onset seizures (POS) and primary generalized tonic-clonic seizures (PGTCS). Study 311 (NCT02849626) was a multicenter, open-label, single-arm study of adjunctive perampanel oral suspension (0.5 mg/mL) in pediatric patients (aged 4 to <12 years) with POS (with/without secondarily generalized seizures [SGS]) or PGTCS. Patients who completed the 311 Core Study could enter Extension Phase A. Here, we report a post hoc analysis of efficacy and safety data from pediatric patients with PGTCS of idiopathic generalized epilepsy (IGE) or non-IGE in the Core and Extension Phases of Study 311. Methods: The Core Study comprised 4-week Pretreatment, 23-week Treatment (11-week Titration; 12-week Maintenance), and 4-week Follow-up (for those not entering Extension A) Periods. Extension A comprised 29-week Maintenance and 4-week Follow-up Periods. This analysis included cumulative data from all enrolled patients (<=23 weeks [for those participating in the Core Study only]; <=52 weeks [for those participating in the Core and Extension A]). Efficacy assessments included median percent change in seizure frequency per 28 days from Baseline, 50% responder rates, and seizure-freedom rates. Safety assessments included monitoring of treatment-emergent adverse events (TEAEs). Results: Overall, 180 patients were enrolled and treated, including 31 patients with PGTCS (24 IGE vs 7 non-IGE). Of the enrolled patients, 136 patients entered Extension A, of which 20 were patients with PGTCS (15 IGE vs 5 non-IGE). Mean (standard deviation [SD]) time from diagnosis was 5.5 (3.6) years and 5.7 (3.9) years for IGE and non-IGE patients, respectively (5.6 [3.6] years for total PGTCS). Median treatment duration was 46.6 and 52.0 weeks for IGE and non-IGE patients, respectively (48.4 weeks for total PGTCS). Mean median (SD) daily dose was 8.4 (3.4) and 5.7 (2.1) mg for IGE and non-IGE patients, respectively (7.8 [3.3] mg for total PGTCS). Median percent reductions in seizure frequency per 28 days for PGTCS of IGE were 70.3%, 70.5%, 61.5%, and 100% for the periods of weeks 1-13, 14-26, 27-39 and 40-52, respectively. For PGTCS of non-IGE, these were 93.2%, 98.3%, 82.7%, and 98.2%, respectively, and for total PGTCS, these were 79.3%, 83.6%, 65.4%, and 100.0%, respectively. 50% responder rates and rates of seizure freedom are presented in Figure 1. An overview of TEAEs are shown in Table 1. The most common TEAEs occurring in patients with PGTCS were: vomiting (6 patients); dizziness, headache, irritability, seizure, and somnolence (5 patients each). Two non-IGE patients reported aggression. No deaths occurred. Conclusions: Data from this limited sample size show no apparent difference in efficacy, tolerability, or safety between patients (aged 4 to ˂12 years) with PGTCS associated with IGE and other forms of epilepsy. Funding: Eisai Inc.