Komodo, a US healthcare claims database, was used to measure medication persistence vs valproate and levetiracetam over 12 months, and healthcare utilization (rescue anti-seizure medication [ASM] use and healthcare visits [ER, outpatient, neurology, inpatient]) over 6 months. Individuals with DS were identified by ICD-10 codes. Individuals with prior/concomitant use of cannabidiol or stiripentol were excluded. Persistence was defined as the duration of continuous medication supply without a gap of >90 days. Kaplan-Meier survival analysis (estimate) and log-rank tests (persistence rates between treatment groups) were used. Percentage change between 6 months prior to the first fenfluramine prescription claim (“Pre”) to the first 6 months of continuous fenfluramine use was measured.

The persistence analysis included individuals with DS who used fenfluramine (n=374), valproate (n=484), and levetiracetam (n=603). The 12-month persistence rate for individuals who initiated fenfluramine (66%) was higher than for those who initiated valproate (34%) or levetiracetam (36%). Fenfluramine was more likely to be persistent than valproate (p<0.001) or levetiracetam (P<0.001).

Pre data was available for 108 individuals with DS; 91 (84%) used fenfluramine continuously for ≥6 months. There was a reduction in rescue ASM use (77%, P<0.001), ER visits (50%, P=0.013), outpatient visits (27%, P=0.009), neurology visits (24%, P=0.07) and inpatient hospitalizations (24%, P=0.39).

Meaningful reductions in healthcare utilization were seen among individuals with DS treated with fenfluramine for ≥6 months. Further, fenfluramine demonstrates a strong persistency compared to valproate and levetiracetam, suggesting improved long-term outcomes.