Significance: Long?term (?4 years) adjunctive perampanel treatment did not raise new safety/tolerability signals and was associated with markedly improved seizure control, particularly in patients with SGS at baseline.
Objective: To evaluate long?term safety/tolerability and seizure outcomes in patients with focal seizures treated with adjunctive perampanel in the open?label extension (OLEx) Study 307 (ClinicalTrials.gov identifier: NCT00735397).
Methods: Patients could enter the OLEx after completing one of the double?blind, phase III studies. Safety/tolerability and seizure outcomes (median percent reduction in seizure frequency per 28 days, and 50% responder and seizure freedom rates) were analyzed during the OLEx in cohorts with the same minimum perampanel exposure for all focal seizures and secondarily generalized seizures (SGS). An additional sensitivity analysis accounted for early dropouts from the OLEx.
Results: Of 1480 patients randomized across the double?blind studies, 1218 enrolled in the OLEx. The majority of patients (65.4%?80.9%) received a last daily dose of perampanel 12 mg and completed long?term assessment on the same, or one fewer, concomitant antiepileptic drug compared with baseline. The long?term safety/tolerability profile was consistent with the double?blind studies.