INTRODUCTION: Subjects with intellectual disability are usually excluded from clinical trials and there is limited evidence-based guidance for the choice of antiseizure medications in this vulnerable population. The study explored the effectiveness of brivaracetam (BRV) in people with epilepsy and intellectual disability. METHODS: BRIVAracetam add-on First Italian netwoRk Study (BRIVAFIRST) was a 12-month retrospective, multicenter study including adults prescribed adjunctive BRV. Main outcomes included the rates of seizure-freedom, seizure response (≥ 50% reduction in baseline seizure frequency), and treatment discontinuation. The occurrence of adverse events (AEs) was also considered. Analyses by the presence and severity of intellectual disability were performed. RESULTS: Subjects with intellectual disability were 253 (24.6%) out of 1029 participants. The 12-month rates of seizure freedom were 18.4% and 10.3% in participants without and with intellectual disability, respectively
the corresponding values for seizure response were 40.0% and 28.9%. Intellectual disability was not an independent predictor of seizure outcomes. The rates of treatment discontinuation were 25.8% and 26.4% in participants without and with intellectual disability. respectively. There were no statistically significant differences in the rates of any AEs, somnolence, nervousness/agitation, and aggressiveness by the presence and degree of intellectual disability. CONCLUSION: Brivaracetam can be a suitable treatment option and offer opportunities for clinical improvement in subjects with intellectual disability and uncontrolled seizures.