To report the final safety, tolerability, and efficacy data from the 311 Core Study following adjunctive treatment with perampanel in patients aged 4 to ?12 years with epilepsy.

Perampanel is a once-daily oral antiepileptic drug for POS and PGTCS. Study 311 (NCT02849626) is a global, multicenter, open-label, single-arm study designed to assess the safety, tolerability, pharmacokinetics, and efficacy of once-daily adjunctive perampanel oral suspension, in pediatric patients (aged 4 to <12 years) with POS (with/without secondarily generalized seizures [SGS]) or PGTCS. 

The Core Study consisted of a 4-week Pre-treatment Period (Screening/Baseline), 23-week Treatment Period (11-week Titration; 12-week Maintenance), and a 4-week Follow-up Period. Endpoints included safety and tolerability (primary endpoint), median percent change in seizure frequency per 28 days from Baseline during the Treatment Period (secondary endpoint), and 50% responder and seizure-freedom rates during Maintenance (Core Study) and longer-term treatment (≤52 weeks; secondary endpoint). 

A total of 180 patients (POS, n=149; PGTCS, n=31) received ≥1 dose of perampanel (mean age [standard deviation], 8.1 [2.09] years; female, 48.9%).  Of these, 146 (81%) patients completed the Core Study and 34 (19%) had discontinued. The most common primary reason for discontinuation was adverse event (AE; n=14 [7.8%]). The median (minimum, maximum) daily dose of perampanel was 8.0 (2, 16) mg/day; median (minimum, maximum) duration of exposure was 22.9 (0, 27) weeks. Treatment-emergent AEs occurring in ≥10% of patients were: somnolence, nasopharyngitis, dizziness, irritability, pyrexia, and vomiting. Median percent reductions in seizure frequency per 28 days were 40.1% (POS), 69.2% (PGTCS), and 58.7% (SGS). Corresponding 50% responder and seizure-freedom rates were 46.6% and 11.5% (POS), 63.6% and 54.5% (PGTCS), and 64.8% and 18.5% (SGS), respectively.

Adjunctive perampanel was generally safe, well tolerated, and efficacious in children aged 4 to ?12 years with POS, SGS, or PGTCS.

Funding: Eisai Inc.