Effectiveness and Safety of Adjunctive Cenobamate in People with Focal-Onset Epilepsy: Evidence from the First Interim Analysis of the BLESS Study

Introduction: Despite new anti-seizure medications (ASMs) being introduced into clinical practice, about one-third of people with epilepsy do not reach seizure control. Cenobamate is a novel tetrazole-derived carbamate compound with a dual mechanism of action. In randomized controlled trials, adjunctive cenobamate reduced the frequency of focal seizures in people with uncontrolled epilepsy. Studies performed in real-world settings are useful to complement this evidence and better characterize the drug profile.

Methods: The Italian BLESS ("Cenobamate in Adults With Focal-Onset Seizures") study is an observational cohort study aimed to evaluate the effectiveness, tolerability, and safety of adjunctive cenobamate in adults with uncontrolled focal epilepsy in the context of real-world clinical practice. The study is ongoing and conducted at 50 centers in Italy. This first interim analysis includes participants enrolled until June 2023 and with 12-week outcome data available.

Results: Forty participants with a median age of 36.5 (interquartile range [IQR] 26.0-47.5) years were included. The median monthly seizure frequency at baseline was 6.0 (IQR 2.5-17.3) seizures and 31 (77.5%) participants had failed four or more ASMs before cenobamate. At 12 weeks from starting cenobamate, the median reduction in monthly seizure frequency was 52.8% (IQR 27.1-80.3%); 22 (55.0%) participants had a ≥ 50% reduction in baseline seizure frequency and six (15.0%) reached seizure freedom. The median number of concomitant ASMs decreased from 3 (IQR 2-3) at baseline to 2 (IQR 2-3) at 12 weeks and the proportion of patients treated with > 2 concomitant ASMs decreased from 52.5% to 40.0%. Seven (17.5%) patients reported a total of 12 adverse events, 11 of which were considered adverse drug reactions to cenobamate.

Conclusion: In adults with uncontrolled focal seizures, the treatment with adjunctive cenobamate was well tolerated and was associated with improved seizure control and a reduction of the burden of concomitant ASMs.

Trial registration number: NCT05859854 (ClinicalTrials.gov Identifier).