<h3>Objective:</h3> Evaluate PK and generate preliminary safety and efficacy data for perampanel oral suspension given as adjunctive therapy in pediatric patients (aged ≥1 to <24 months) with epilepsy in Study 238 (NCT02914314). <h3>Background:</h3> Perampanel is a once-daily oral antiepileptic drug (AED) for partial-onset seizures and primary generalized tonic-clonic seizures. <h3>Design/Methods:</h3> Study 238 is a multicenter, open-label Phase II study comprising the Pretreatment and Treatment Phases (Core Study), and the Extension Phase. Planned enrollment is ≥16 patients with evaluable PK data. The primary endpoint is perampanel PK during the Maintenance Period of the Core Study. Secondary (safety) endpoints include incidence rate of treatment-emergent adverse events (TEAEs) and clinical laboratory parameters. Perampanel is initiated at 0.5 mg/day and titrated to a maximum dose of 12 mg/day (patients taking non–enzyme-inducing AEDs [EIAEDs]) or 16 mg/day (patients taking EIAEDs) based on clinical response and tolerability. <h3>Results:</h3> As of July 26, 2018, 11 patients were enrolled and 9 (2 aged >6 to ≤12 months and 7 aged >12 to <24 months) entered into the Core Study. Of these, 7 have completed the Core Study, 1 is ongoing, and 1 discontinued due to inadequate therapeutic effect. Limited PK data, based on dose-normalized plasma concentrations, from 7 patients (aged >6 to <24 months; 1 taking EIAEDs) suggested that perampanel exposure was within the range of patients aged ≥2 years. TEAEs were experienced by 8 (88.9%) patients, and treatment-related TEAEs occurred in 5 (55.6%) patients. The most common TEAEs were upper respiratory tract infection (55.6%), pyrexia (44.4%), nasopharyngitis (33.3%), and somnolence (33.3%). <h3>Conclusions:</h3> Preliminary data suggest that perampanel is safe and well tolerated in pediatric patients with epilepsy aged >6 to <24 months and perampanel exposure is comparable with patients aged ≥2 years. The safety profile is consistent with prior clinical studies. Enrollment is ongoing. <b>Funding:</b> Eisai Inc. <b>Disclosure:</b> Dr. Renfroe has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with Eisai, Livanova, Ipsen. Dr. Rozentals has nothing to disclose. Dr. Aluri has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with Eisai. Dr. Umetsu has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with Eisai. Dr. Ma has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with Eisai. Dr. Laurenza has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with Eisai and Takeda. Dr. Ngo has received personal compensation for consulting, serving on a scientific advisory board, speaking, or other activities with Eisai.