Efficacy and safety of adjunctive perampanel in patients with focal seizures or generalized tonic-clonic seizures: Post hoc analysis of Phase II and Phase III double-blind and open-label extension studies in India

Objective: This post hoc analysis assessed the efficacy and safety of adjunctive perampanel in patients (aged ≥ 12 years) with focal seizures (FS), with/without focal to bilateral tonic-clonic seizures (FBTCS), or generalized tonic-clonic seizures (GTCS) in India.

Methods: Centers in India were identified from six double-blind, randomized, Phase II and Phase III studies of adjunctive perampanel (2-12 mg/day) and their open-label extensions (OLEx). Efficacy assessments included median percent change in seizure frequency per 28 days, 50% and 75% responder and seizure-freedom rates. Treatment-emergent adverse events (TEAEs) were monitored.

Results: Overall, 128 patients (placebo, n = 39; perampanel, n = 89) were included in the double-blind Safety Analysis Set and 126 (FS, n = 113 [placebo, n = 32; perampanel, n = 81]; FBTCS, n = 35 [placebo, n = 14; perampanel, n = 21]; GTCS, n = 13 [placebo, n = 6; perampanel, n = 7]) comprised the Full Analysis Set. Median percent reductions in seizure frequency per 28 days for placebo vs perampanel for Indian patients were as follows: 34.8% vs 49.8% (FS; not significant [NS]) and 43.1% vs 60.5% (FBTCS; NS) at 4-12 mg/day, respectively, and -22.4% vs 8.2% (GTCS; NS) at 8 mg/day, respectively. Fifty-percent responder rates were 37.5% vs 55.1% (FS; NS), 42.9% vs 60.0% (FBTCS; NS), and 16.7% vs 42.9% (GTCS; NS), respectively; seizure-freedom rates were 0.0% vs 5.8%, 7.1% vs 10.0%, and 0.0% vs 14.3%, respectively (all NS). Overall, 110 patients entered OLEx studies (FS, n = 99; GTCS, n = 11). Perampanel was efficacious for up to four years for FS and FBTCS and two years for GTCS. Across double-blind and OLEx studies, TEAEs occurred in 58.4% and 83.6% of Indian perampanel-treated patients, respectively; dizziness was most common. Efficacy and safety outcomes were generally similar overall between Indian and non-Indian patients.

Significance: These data suggest adjunctive perampanel (up to 12 mg/day) may be a suitable anti-seizure medication for patients (aged ≥ 12 years) with FS, with/without FBTCS, or GTCS in India.