AbstractBackgroundPerampanel is an antiepileptic drug. Some studies have documented the efficacy of perampanel in epileptic spasms. We aimed to evaluate the efficacy and safety of adjunctive perampanel therapy (PT) in patients with epileptic spasms.MethodsWe retrospectively surveyed the efficacy and safety of adjunctive PT in 14 patients with epileptic spasms at the Saitama Children's Medical Center between June 2016 and September 2021. Seizure outcomes and safety were evaluated 12 months after commencing PT. Response to perampanel was defined as complete remission of epileptic spasms for more than 3 months.ResultsThe median age at onset of epileptic spasms was 0.4 years (range, 0.1–1.3 years). The etiology was structural in 11 patients, genetic in two, and unknown in one. The median age at the commencement of PT was 3.2 years (1.5–10.3 years). The initial and maintenance doses of perampanel were administered at 0.04 (range, 0.02–0.05) mg/kg/day and 0.12 (range, 0.03–0.24) mg/kg/day, respectively. Five of the 14 patients (35.7%) showed remission of epileptic spasms for more than 3 months at 12 months after PT; these patients had a structural etiology. The median duration between commencement of perampanel and spasm remission was 2 months (range, 1–6 months). No serious adverse effects occurred.ConclusionsThis is the first case series evaluating adjunctive PT for epileptic spasms. PT is worth investigating to treat epileptic spasms in patients with structural etiologies. As our study population primarily comprised children aged 2 years and older, PT may be useful for epileptic spasms beyond infancy.