Abstracts

This is a Late Breaking abstract

Rationale: Cenobamate is a novel anti-seizure medication (ASM) approved for the treatment of focal-onset seizures in adults. Despite its adverse effect (AE) profile and potential for drug reaction with eosinophilia and systemic symptoms (DRESS), cenobamate is an appealing option because of its potential efficacy. After more than two years of utilizing cenobamate at the UAB Epilepsy Center, the efficacy of cenobamate was evaluated retrospectively in the outpatient setting. 

Methods: All outpatient prescriptions for cenobamate for any patient seen by any UAB provider from May 13, 2000, to August 12, 2022, were identified. Clinical response was recorded at the first documented assessment of seizure frequency for the patient’s current dose at the time of data collection. Pharmacy and clinic notes, as well as electronic medical record patient messaging, were utilized to derive clinical data.

Results: Ninety-two patients were identified with at least one cenobamate prescription. We included 58 patients in the evaluation. Of this group, 34 (58.6%) were able to tolerate and maintain on cenobamate. Doses ranged from 75 to 400 mg/day. In patients currently taking cenobamate, seizure freedom was noted in 9 (26.5%) patients at the time of first assessment. The average time to first seizure frequency assessment for all patients currently on cenobamate was 2.6 months (Figure 2). _x000D_  _x000D_ In the evaluation group, cenobamate was discontinued in 24 (41.4%) patients due to AEs or lack of effectiveness. AEs were the most common reason for discontinuation of cenobamate, followed by a reported worsening of seizures. The most commonly reported AEs were somnolence and dizziness. One patient experienced rash and hives, but occurred when cenobamate was resumed at 200 mg once daily after being off the drug for >1 week. The patient also attributed the rash and hives to a concomitant antibiotic. No known episodes of DRESS were observed. _x000D_  _x000D_ We also noted concomitant ASM in these patients. Of the 34 patients currently taking cenobamate, 24 (70.6%) required either a dose adjustment or discontinuation of a concomitant ASM due to AEs prior to their assessment. Adjustments and/or discontinuation of clobazam (10; 41.7%) and carbamazepine (5; 14.7%) were most common. In the 24 patients that discontinued cenobamate, 16 (66.7%) were due to intolerable adverse events. The most common concomitant ASMs in the entire discontinuation group were lamotrigine (12; 50%), cannabidiol (8; 33.3%) and lacosamide (7; 29.2%).

Conclusions: For patients that were able to tolerate cenobamate, rates of seizure reduction and seizure-freedom at early assessment are encouraging. However, drug-drug interactions and frequent AEs limit its use. Clinicians need to anticipate possible interactions between cenobamate and other ASMs. Additionally, studies of longitudinal assessment of cenobamate efficacy are needed.

Funding: Not applicable