Real‐world anti‐seizure treatment and adverse events among individuals living with drug‐resistant focal epilepsy in the United States

Abstract Objective This study aimed to understand how people living with drug‐resistant focal epilepsy (DRE) navigate through lines of antiseizure medications (ASM) and experience adverse events (AEs) in the real‐world setting in the United States. Methods A retrospective study was conducted with medical chart data from clinical practices in the United States. Eligible adults had a confirmed diagnosis of DRE and initiated a third‐line ASM therapy between January 2013 and January 2020 (i.e., the index date ). Subjects must have medical history data available for ≥1 year prior to ( the baseline ) and ≥2 years after the index date ( the follow‐up ). Treatment patterns were captured from first to fourth lines. After the emergence of drug resistance, time to ASM discontinuation, reasons for discontinuation, AE experience and AE management were reported separately during third and fourth lines of treatment and beyond. Results The study included a total of 345 individuals, with an average (standard deviation) age of 23.9 (11.9) years at first diagnosis. All individuals had at least three lines of ASMs with first and second lines during baseline, and third line during follow‐up. The first line for most individuals was monotherapy. As individuals progressed through additional lines of ASM therapy, they were more likely to receive polytherapy. The regimens were more individualized after meeting drug resistance criteria. The top reasons for discontinuing were uncontrolled seizure and/or intolerance/AEs for both third and subsequent lines. More than a third of individuals experienced at least one AE. Among those with at least one AE, many individuals had to manage these AEs with dose adjustment (39.4%), discontinuation of offending ASM (37.9%), de novo pharmacotherapy (25.8%), emergency room visit (13.6%), and hospitalization (12.1%). Significance This study demonstrated that individuals living with DRE experience significant AEs, and many of these AEs lead to treatment disruption and significant healthcare resource utilization. Plain Language Summary This study examined how individuals with focal epilepsy are treated across various clinics in United States and reported the adverse events these individuals experienced during treatment, along with the consequence associated with these adverse events. We found that as individuals progressed through additional treatments, they were more and more likely to receive more than one antiseizure medication, and a significant portion of individuals experienced at least one adverse event, often manifested as headache, somnolence, dizziness, and fatigue.