Real-world analysis of retention on cenobamate in patients with epilepsy in the United States

Abstract

Background: This retrospective, observational study used US claims data to assess retention rates on cenobamate compared with four branded antiseizure medications (ASMs) in patients with epilepsy.

Methods: Adults (≥18 years) with prevalent epilepsy (ICD-10 code G40.xx) and ≥ 1 prescription for cenobamate or any of the newer branded ASMs (brivaracetam, eslicarbazepine, lacosamide, or perampanel) between May 1, 2020 and December 31, 2021 were identified from the HealthVerity Marketplace database. At least 360 days of continuous enrollment was required before and after the index date (Day 1 of initiating cenobamate or branded ASM). Patients were followed until cessation of cenobamate or branded ASM or the end of data collection using Kaplan-Meier methods. Retention was compared between cenobamate and the branded ASMs (both as a group and individually) using Chi-square tests.

Results: In total, 4109 patients were included (195 cenobamate; 3914 branded ASMs). A higher proportion of patients in the cenobamate group compared with the branded ASMs group had concurrent focal and generalized epilepsy (65.6% vs 40.0%) and were on ≥ 3 concomitant ASMs (48.2% vs 12.8%) at the index date. Median time to discontinuation (i.e., the time that half the patients discontinued) was not quite reached after 12 months in the cenobamate group (50.3% of patients remained on cenobamate) and was 7.7 months in the branded ASMs group. Retention was significantly higher with cenobamate vs the branded ASMs group (p = 0.04545) and vs the individual ASMs lacosamide (p = 0.03044) and perampanel (p = 0.01558). Twelve-month retention rates (95% confidence intervals) were 50.3% (43.1%-57.0%) for cenobamate, 40.5% (38.9%-42.0%) for branded ASMs overall, 42.3% (38.6%-46.0%) for brivaracetam, 44.1% (39.2%-49.0%) for eslicarbazepine, 39.9% (38.0%-41.8%) for lacosamide, and 36.8% (31.9%-41.8%) for perampanel.

Conclusions: In this real-world analysis, retention was significantly higher with cenobamate vs a pooled group of four branded ASMs despite a greater frequency of patients in the cenobamate group having characteristics of more difficult-to-treat epilepsy.

Keywords: Antiseizure medication; Cenobamate; Epilepsy; Real-world; Retention.