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

BackgroundIn 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.ObjectiveTo 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.MethodsThis 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.ResultsA 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%).ConclusionsCNB 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.