Open-label study to investigate the safety and efficacy of adjunctive perampanel in pediatric patients (aged 4 to <12 years) with inadequately controlled focal-onset seizures: Japanese subgroup analysis.

PURPOSE: To evaluate the safety and tolerability of adjunctive perampanel in a Japanese subpopulation of Study 311 (NCT02849626), which was a global, multicenter, open-label, single-arm study of children (aged 4 to <12 years) with inadequately controlled focal-onset seizures (FOS), with or without focal to bilateral tonic-clonic seizures (FBTCS) or generalized tonic-clonic seizures (GTCS). METHODS: Study 311 comprised a Core Study, Extension A, and Extension B; this report focuses on the Japanese patient subgroup in the Core Study only. In the Core Study, Japanese patients (FOS only) received adjunctive perampanel ≤12 mg/day in a 23-week Treatment Phase. Endpoints included safety/tolerability (primary) and median percent change in seizure frequency per 28 days from baseline. Patients were stratified by age and concomitant enzyme-inducing anti-seizure medication (EIASM) use. RESULTS: Of 65 enrolled Japanese patients, 56 completed the Core Study and nine withdrew. The most common reason for discontinuation was adverse events (AEs) (n = 4 [6.2%]). The mean (standard deviation) daily dose of perampanel in Japanese FOS patients was 5.8 (2.2) mg/day. During the Core Study, treatment-emergent AEs (TEAEs) were reported by 89% of Japanese patients, most commonly nasopharyngitis (28%) and somnolence (28%). The median percent reduction in seizure frequency per 28 days from baseline was 37% and the lower limit of the 95% CI was greater than 10.5%, satisfying the pre-defined efficacy criteria. Perampanel was effective regardless of age or concomitant EIASM use. CONCLUSION: Perampanel as adjunctive therapy is generally safe, well-tolerated, and efficacious in Japanese children aged 4 to <12 years with FOS (with/without FBTCS).

Bioequivalence of perampanel fine granules and tablets in healthy Japanese subjects.

OBJECTIVE: Perampanel is an approved anti-seizure drug. A new formulation of perampanel fine granules (FG; 1% perampanel) has been developed for patients who are unable to take tablets. Bioequivalence between the 4-mg FG and tablet perampanel formulations, as well as their safety and tolerability, were assessed. MATERIALS AND METHODS: In this phase I, single-center, open-label, 2-period, 2-sequence, crossover, bioequivalence study (NCT03399734), healthy Japanese subjects were randomized to receive single doses of the 4-mg FG perampanel and 4-mg perampanel tablet (separated by a ≥ 6-week washout period). Plasma samples for perampanel concentration analysis were collected pre-dose and at intervals up to 168 hours post-dose. The maximum observed concentration (Cmax) and area under the concentration-time curve from time zero to 168 hours (AUC(0-168h)) were used to assess the bioequivalence of the two formulations. RESULTS: The 90% confidence intervals (CIs) for the geometric mean ratio of test/reference for Cmax and AUC(0-168h) were within the bioequivalence criteria of 80 - 125% (Cmax 90% CI 90.8%, 110%; AUC(0-168h) 90% CI 98.2%, 112%; N = 21). 10/24 (41.7%) subjects with FG experienced ≥ 1 treatment-emergent adverse event (TEAE). The events were mild in severity and resolved within 4 hours of onset. There were no deaths, severe TEAEs, serious AEs, or TEAEs leading to study-drug withdrawal. CONCLUSION: Bioequivalence of 4-mg FG and 4-mg tablet of perampanel was demonstrated. Both perampanel formulations were generally safe and well tolerated. These data suggest that perampanel FG may be a suitable alternative formulation for patients with epilepsy who have difficulties taking perampanel tablets.