Background and importance More than one-third of patients with epilepsy have uncontrolled seizures despite being treated with two or more anti-seizure medications (ASM); this condition is known as refractory or drug-resistant epilepsy. Cenobamate is a new ASM that has been recently approved by the European Medicines Agency for the adjunctive treatment of focal-onset seizures in adults with drug-resistant epilepsy. In the Spanish system, cenobamate is a drug that is dispensed in hospitals and, since August 2020, access to it has been made through the compassionate use programme. Because of its newness, real-world data regarding cenobamate use are currently very limited.

Aim and objectives The aim of this study was to evaluate the effectiveness and safety of cenobamate in real-world practice.

Material and methods We conducted a single-centre, retrospective study of patients who received cenobamate in our hospital between September 2020 and September 2021.The patients included in the study must have received cenobamate for at least 3 months. Demographic and clinical variables were collected by reviewing medical records. The efficacy outcome was the proportion of patients who exhibited a 50% or greater reduction in the monthly seizure frequency from baseline (50% responder rate). We also recorded adverse events (AEs) and estimated the rate of discontinuation of treatment.

Results All the patients included in the study (n=30) were adults with focal-onset epilepsy who had uncontrolled seizures despite a history of treatment with ASMs. Patients were treated with one to five concomitant ASMs during the study period and 43.3% of them reduced the number of ASMs with one or two. The daily dose of cenobamate ranged from 50 to 400 mg/day. The 50% responder rate was 53.3%, with a median of 50% (IQR 31.2; 73.3) in the reduction of monthly seizure frequency.73.3% of patients had nervous system disorders (somnolence, dizziness, dysarthria, etc.), 16.67% had gastrointestinal AEs and 6.67% showed skin disorders (one of them had rash erythematous). The discontinuation rate because of AEs was 13.3%.

Conclusion and relevance The effectiveness and safety data obtained are similar to those of the clinical trial. We found that adjunctive treatment with cenobamate allows a reduction in the number of concomitant ASMs in an important proportion of the patients.

Conflict of interest No conflict of interest