Randomized phase III study 306 Adjunctive perampanel for refractory partial-onset seizures

Objective: To evaluate the efficacy and safety of perampanel 2, 4, and 8 mg/day added to 1-3 concomitant antiepileptic drugs (AEDs) in patients with uncontrolled partial-onset seizures. Methods: During this double-blind, placebo-controlled trial, patients with persisting seizures on 1-3 AEDs were randomized to perampanel 2, 4, and 8 mg/day or placebo following a 6-week baseline phase. Perampanel was titrated weekly by 2 mg/day and maintained at the dose achieved for 13 weeks. Primary endpoints were median percent change in seizure frequency and 50% responder rate. Analysis of covariance was performed on all treated patients with any seizure data (recorded in daily diaries) in the double-blind phase. Results: A total of 706 patients were randomized and received trial medication; 623 completed the trial. Median percent change in seizure frequency-the primary efficacy endpoint-was -10.7%, -13.6%, -23.3%, and -30.8% for placebo, perampanel 2, 4, and 8 mg/day, respectively. The difference from placebo was statistically significant for perampanel 4 mg/day (p = 0.0026) and 8 mg/day (p < 0.0001). The corresponding 50% responder rates were 17.9%, 20.6%, 28.5%, and 34.9%. The difference from placebo was statistically significant for perampanel 4 mg/day (p = 0.0132) and 8 mg/day (p = 0.0003). An apparent dose response was suggested for dizziness, which was the most frequent treatment-emergent adverse event. Conclusions: This trial demonstrated that adjunctive perampanel effectively reduced seizure frequency and possessed a favorable tolerability profile in patients -12 years with partial-onset seizures (with or without secondary generalization), with a minimum effective dose of 4 mg/day. Classification of Evidence: This study provides Class I evidence that 4 and 8 mg/day doses of adjunctive perampanel are effective and tolerated in reducing partial-onset seizures.