Effectiveness and safety of adjunctive cenobamate for focal seizures in adults with developmental disability treated in clinical practice

•92.9% (26/28 patients) continued cenobamate through 6 months, showing high retention.•High responder rates/substantial focal seizure reduction occurred with cenobamate.•100% seizure reduction occurred in 48.2% of patients at 6 months.•Adverse effects were often mitigated by concomitant antiseizure medication reduction. Effectiveness and tolerability of adjunctive cenobamate for uncontrolled focal seizures in adults living with a developmental disability are not defined. Retrospective medical record review included adults ≥18 years old living with a developmental disability, either in a group home or with parents, and experiencing uncontrolled focal seizures despite stable doses of ≥1 antiseizure medication (ASM). Effectiveness was examined as percentage change in focal seizure frequency per month from the 2-month average before cenobamate to the average of months 5 and 6 while receiving cenobamate. Percentages of patients achieving responder rates in focal seizure frequency at 6 months of cenobamate treatment were examined. Adverse effects and concomitant ASM dosage adjustments were assessed. Of the 28 included patients, 26 (92.9%) continued cenobamate beyond 6 months. The responder rate of 100% seizure reduction (seizure-free) occurred in 48.2% of the patients who continued cenobamate for 6 months. Ten adverse effects were reported in 9 patients (32.1%), and 80% (8/10) were resolved by reducing concomitant ASM dosages. Two patients (7.1%) discontinued cenobamate due to adverse effects. Cenobamate resulted in substantial reduction in focal seizure frequency and was well tolerated.