First-year Experience with Brivaracetam in Japan: Real-world Data from Juntendo Epilepsy Center

Approximately 30% of patients still develop drug-resistant epilepsy despite the introduction of newer antiseizure medications. Brivaracetam, a high-affinity synaptic vesicle protein 2A ligand with a mechanism of action similar to that of levetiracetam, was only recently approved in Japan in June 2024 and became available at our institution in September 2024. Clinical data in real-world settings remain limited. To date, no real-world clinical data have been systematically reported in patients in Japan, and the present study aimed to characterize the initial real-world experience with Brivaracetam use shortly after its approval. We retrospectively analyzed 73 patients with focal epilepsy who initiated Brivaracetam at our center between September 2024 and August 2025, evaluating patient characteristics, seizure outcomes, treatment retention, and adverse events. Among 41 patients with at least 3 months of follow-up, seizure freedom was achieved in 5%, whereas 44% of patients were responders with ≥50% seizure reduction. Overall, 59 patients continued Brivaracetam, with a treatment retention rate of 76.5% and a mean treatment duration of 7.4 months. Adverse events were observed in 18 patients (24%), most frequently somnolence, followed by dizziness and irritability. Brivaracetam discontinuation occurred in 14 patients (19%), with psychiatric symptoms leading to discontinuation in only 3 patients (4%), a lower rate compared with prior reports of levetiracetam. These findings suggest that Brivaracetam is effective and generally well tolerated in patients in Japan with focal epilepsy. Future multicenter prospective studies with longer follow-up are warranted to further evaluate the role of Brivaracetam, including as monotherapy and in patients with multilobar epilepsy.