Post-marketing Experience with Cenobamate in the Treatment of Focal Epilepsies: A Multicentre Cohort Study.

Background: In randomised controlled trials, adjunctive cenobamate (CNB) has been shown to reduce seizure frequency in patients with drug-resistant focal epilepsy. Studies conducted in real-world settings provide valuable complementary data to further characterise the drug's profile.

Objective: To assess the efficacy, retention and tolerability of adjunctive cenobamate (CNB), and to identify factors that might predict these outcomes in the clinical treatment of focal epilepsies.

Methods: This multicentre, retrospective cohort study included all patients who began CNB treatment between October 2020 and April 2023 at seven participating epilepsy centres. Baseline and follow-up data were collected from patients' medical records, covering clinical characteristics and outcome data such as seizure frequency, dosing of CNB, physician-assessed Clinical Global Impression of Change, treatment-emergent adverse events (TEAEs), CNB retention and reasons for discontinuation.

Results: A total of 234 patients [mean age 40.7 ± 14 years, median 40 years, range 11-82 years; five adolescents under 18 years; 99 (42.3%) males] were analysed. The mean epilepsy duration at study entry was 23.2 ± 14.5 years (median 21 years, range 0.75-63 years), with the average age of epilepsy onset being 17.5 ± 13.0 years (median 17 years, range 0.1-71 years). The patients were taking a mean of 2.6 ± 0.8 (median 3) anti-seizure medications (ASMs) before starting CNB, and had failed a mean of 6 ± 3.3 (median 6) of further ASMs in the past. CNB exposure ranged from 5 to 1162 days, amounting to a total exposure time of 264.7 years. The retention rate was 92.6% at 3 months, 87.2% at 6 months and 77.8% at 12 months. At 3 months, 52.6% achieved a 50% seizure reduction, with 14.5% reporting seizure freedom; by 12 months, 47.7% maintained a 50% response rate and 11.9% were seizure-free. No significant differences in responder rates were observed based on sex, aetiology, seizure localisation, number of ASMs or target dose. The mean maximum CNB dose was 236.7 ± 97.4 mg (median 200 mg, range 12.5-450 mg), with 28 patients (12.0%) titrated up to 400 mg or above. During CNB treatment, 43.6% of patients were able to discontinue, and a further 24.4% were able to reduce the dose of a concomitant ASM. During CNB treatment, 144 patients (61.5%) experienced TEAEs. The most common TEAEs were sedation (n = 84, 35.9%), dizziness (n = 58, 24.8%) and ataxia (n = 23, 9.8%).

Conclusions: CNB showed a relatively high and clinically useful 50% responder rate of 47.7% and an overall retention of 77.8% at 1 year. We were unable to identify specific predictors for response and retention, indicating that CNB may be beneficial for patients with a history of multiple failed ASMs, a high number of concomitant ASMs and any localisation or aetiology of focal epilepsy.