Fenfluramine for developmental and epileptic encephalopathy with spike-wave activation in sleep (DEE-SWAS): An...

To evaluate the safety and potential efficacy of fenfluramine (FFA) in patients with developmental and epileptic encephalopathy with spike-and-wave activation in sleep (DEE-SWAS).

We conducted an open-label, interventional, exploratory study of FFA in pediatric patients with DEE-SWAS. We assessed changes in seizure frequency, intensity, and spike-wave index (SWI), as well as non-seizure outcomes including a neuropsychological evaluation with BRIEF®-2 and Vineland-3 questionnaires, assessment of sleep habits, and caregiver-reported changes in cognitive, behavioral and motor symptoms. Adverse effects and changes in concomitant antiseizure medications (ASMs) were recorded.

Six patients were included (2 females, median age 10 years, range 4-11 years), with a median follow-up of 12 months (9-13 months). FFA was well tolerated; only two patients experienced mild, transient adverse events, and all participants continued treatment throughout the study. SWI improved in 4/6 patients (66.7 %), with ≥ 50 % reduction in two (near-resolution in one). Seizures were reported as less severe, although their frequency remained unchanged. The total dose of concomitant corticosteroids and ASMs was reduced in 66.7 % of patients. Executive functioning showed a tendency to improvement in 4/6 patients (66.7 %) based on BRIEF®-2 scores, although Vineland-3 scores remained stable. Caregivers also reported perceived improvements in behavior, cognition, and sleep.

FFA was a safe and potentially effective treatment in our cohort of patients with DEE-SWAS. We observed a reduction of SWI in most patients, along with modest improvements in executive function. These preliminary findings support the need for larger studies to confirm efficacy and explore long-term outcomes.