Background Perampanel, a selective, non-competitive AMPA receptor antagonist, is approved for adjunctive treatment of focal seizures, with or without secondary generalised seizures, and for primary generalised tonic-clonic seizures in patients with epilepsy aged ≥12 years.

Methods We analysed the seizure outcomes of individuals with focal seizures who discontinued all non-perampanel antiepileptic drugs (AEDs) and continued to receive perampanel (up to 12 mg/day) as monotherapy in two open-label extension (OLEx) studies: Study 307 (NCT00735397) and the Study 235 OLEx (NCT01161524).

Results Seven patients discontinued all concomitant AEDs and took perampanel as monotherapy (Study 307, n=6; Study 235 OLE, n=1; female, n=1; age range, 15–40 years) for up to 1099 days (157 weeks). Seizure data were available for six patients, of whom five had a≥90% reduction in overall seizure frequency between baseline and their last 13 week period of monotherapy (three were seizure-free). Five patients experienced treatment-emergent adverse events (TEAEs) during perampanel monotherapy; no TEAEs occurred in more than one patient. There were no deaths and only one serious TEAE (colitis), which was not considered related to perampanel treatment.