To assess healthcare resource utilization (HCRU), antiseizure medication (ASM) claims, and treatment persistence in patients with LGS receiving fenfluramine from a large US claims database.

This was a retrospective study of patients with LGS (ICD-10, G40.81) from 1/1/2022–12/31/2024 using the Komodo US healthcare claims database. Patients had ≥1 fenfluramine prescription claim (initiation date was first claim) and ≥2 LGS claims (≥1 month apart).

The primary endpoint, differences in HCRU, number of unique ASMs and average ASM claims before and after fenfluramine initiation, was evaluated using paired t-tests. For this endpoint, 12 months of claims data before and after the first fenfluramine prescription claim with no gaps in fenfluramine prescription claims >14 days were required.

The secondary endpoint, fenfluramine treatment persistence, required continuous fenfluramine claims with no gaps >90 days and was evaluated using Kaplan–Meier analysis. For this endpoint, ≥3 months pre-fenfluramine and ≥6 months post-fenfluramine data were required.

In 148 patients who met the primary endpoint criteria, there were significant changes in mean (pre vs. post) all-cause inpatient hospitalization claims (4.0 vs. 3.1, P=0.04), seizure-related inpatient hospitalization claims (−23.6%, P=0.04), all-cause emergency room (ER) visit claims (−42.4%, P<0.01), seizure-related ER visit claims (−46.4%, P<0.01), ambulance use claims (−61.8%, P<0.01), all ASM claims (−9.3%, P<0.01), and average number of unique ASMs (−12.2%, P<0.01) before and after fenfluramine initiation.

In 544 patients who met the secondary endpoint criteria, fenfluramine persistence was 73% and 61% at 6 and 12 months, respectively. No significant indicators of persistence were identified.