Abstracts

Rationale: Perampanel is a novel first-in-class antiepileptic drug (AED) developed and launched in Japan in 2016 for the treatment of partial-onset seizure (including secondarily generalized seizure) or primary generalized tonic-clonic (PGTC) seizure in combination with other AEDs. Since large-scale studies on the long-term safety and efficacy of perampanel are limited, a Japanese post-marketing surveillance in a real-world setting was conducted to evaluate the safety and efficacy of long-term perampanel administration. Methods: The authors are currently conducting two long-term prospective observational real-world studies on perampanel in patients with epilepsy: one is for patients 12-17 years of age for a duration of up to 104 weeks (Study 1) and another is for patients age 18 years or older for a duration of up to 52 weeks (Study 2). Herein, we report the results of an interim analysis of these studies. All studies have been conducted in accordance with Good Post-marketing Study Practice in Japan. Data on case report forms collected between August 1, 2016, and July 22, 2018, were included in the analysis. Results: Data on case report forms collected from 89 patients in Study 1 and 1659 patients in Study 2 were included in the analysis.The patient characteristics were as follows (Study 1, Study 2): female: 41.6%, 48.0%; mean age: 14.3 years, 43.3 years; proportion of patients with epilepsy duration of >= 10 years: 61.8%, 73.9%. Regarding adjunctive therapy, 88.6% (Study 1) and 74.7% (Study 2) of patients concomitantly received two or more AEDs. For patients who received perampanel as the second AED, the top two most commonly used primary AEDs were levetiracetam (50.0%) and carbamazepine (20.0%) in Study 1, levetiracetam (44.4%), and sodium valproate (22.1%) in Study 2.At Week 52, 55.1% (Study 1) and 61.2% (Study 2) of patients were still on perampanel. Regarding safety, the most common adverse reactions were somnolence (10.11% in Study 1, 11.27% in Study 2), dizziness (6.74% in Study 1, 9.26% in Study 2), and irritability (10.11% in Study 1, 3.53% in Study 2).Regarding efficacy, the proportions of patients who achieved a >=50% reduction in seizure frequency at Week 52 in Study 1 and Study 2 were 91.7% and 61.5% for partial-onset seizure (with motor signs), 80.0% and 52.6% for partial-onset seizure (without motor signs), 65.0% and 52.5% for complex partial seizure, 81.8% and 72.5% for secondary generalized seizure, and 50.0% and 68.4% for PGTC seizure, respectively. Conclusions: The results of this interim analysis of real-world post-marketing surveillance regarding the safety and efficacy of perampanel were consistent with results obtained in clinical trials. This is the largest multicenter study in Japan and demonstrates the actual situation of daily clinical practice. The authors will continue data collection and report the results of the final analysis. Funding: Eisai Co., Ltd.