Age-stratified long-term outcomes of perampanel in focal seizure: A multicenter real-world study in South Korea

Objective Perampanel (PER) is a third-generation antiseizure medication (ASM) increasingly used in clinical practice. However, evidence regarding its long-term effectiveness and safety in elderly patients remains limited, particularly in Asian populations. Methods This multicenter, retrospective, longitudinal study included patients with focal seizures treated with PER at eight tertiary hospitals in South Korea between 2016 and 2024. Patients with primarily generalized seizures or insufficient baseline or follow-up data were excluded. Elderly patients were defined as those aged 65 years or older. Treatment retention rate, effectiveness, and adverse events were assessed over a follow-up period of up to three years. Effectiveness at 12 months was defined based on responder status or seizure freedom. Multivariate logistic regression analyses were performed to identify factors associated with effectiveness and adverse events. Results A total of 528 patients were included, of whom 108 were elderly. Overall retention rates were 59.1% at 12 months and 23.7% at 36 months. Elderly patients showed generally favorable treatment responses, with higher responder and seizure-free rates compared with non-elderly patients. Psychiatric comorbidity and multifocal epileptogenic zone localization were independently associated with reduced 12-month effectiveness. In contrast, focal slowing on scalp electroencephalography was positively associated with effectiveness and remained significant after age adjustment. Adverse events occurred in 50.8% of patients and were less frequent in the elderly group. Fast titration within two weeks was a strong independent risk factor for moderate to severe adverse events. Conclusion In this study, PER demonstrated sustained effectiveness and acceptable tolerability across age groups. Careful titration and consideration of comorbidity and electroencephalographic features may support more individualized PER use, particularly in elderly patients.