First add-on perampanel for focal-onset seizures: An open-label, prospective study

Objectives This study aimed to determine the efficacy and safety of perampanel added to monotherapy in patients with focal-onset seizures, with or without secondarily generalized tonic-clonic seizures. Materials & methods In this multicentre, open-label trial, enrolled patients were treated with perampanel monotherapy. During a 12-week titration period, perampanel was incrementally increased by 2 mg/d over ≥2-week intervals. Patients then entered a 24-week maintenance period. The primary objective was to investigate the 50% responder rate in total seizure frequency, with 75% and 100% responder rates as secondary objectives. Treatment-emergent adverse events (TEAEs) and adverse drug reactions were recorded. A post hoc analysis was performed to investigate the effect of titration speed and different concomitant AEDs on the efficacy and safety of perampanel. Results Of the 85 patients analysed, seizure reductions of 50%, 75% and 100% were observed in 80.0% (95% confidence interval [CI]: 69.9-87.9), 71.8% (95% CI: 61.0-81.0) and 47.1% (95% CI: 36.1-58.2) during the maintenance period, respectively. The 50%, 75% and 100% response rates in patients with secondarily generalized tonic-clonic seizures were 87.5% (95% CI: 61.7-98.5), 87.5% (95% CI: 61.7-98.5) and 75.0% (95% CI: 47.6-92.7), respectively. The most common TEAEs were dizziness (50.0%), somnolence (9.8%) and headache (8.8%). The efficacy outcomes and safety profile of perampanel were more favourable with slow titration and relatively consistent when stratified by concomitant AEDs. Conclusions Perampanel was effective and well tolerated as a first add-on to monotherapy in patients with focal-onset seizures, with or without secondarily generalized seizures.