Researchers investigated the safety and efficacy of fenfluramine for treating patients with Dravet syndrome who have frequent seizures despite taking a stiripentol-inclusive antiepileptic drug regimen. They conducted a double-blind, placebo-controlled, parallel-group randomized clinical trial at multiple centers randomizing patients with 6 or more convulsive seizures during the 6-week baseline period to receive fenfluramine, 0.4 mg/kg/d (maximum, 17 mg/d), or a placebo. Outcomes revealed a 54.0% greater reduction in mean monthly convulsive seizure frequency in correlation to receiving oral fenfluramine (0.4 mg/kg/d; maximum 17 mg/d) vs placebo among patients with Dravet syndrome who were taking stiripentol-containing antiepileptic drug regimens.
Among patients who were taking fenfluramine (vs placebo), a significantly greater proportion experienced a clinically meaningful (over 50%) or profound (over 75%) reduction in monthly convulsive seizure frequency. Adverse events most commonly encountered were decreased appetite, pyrexia, fatigue, and diarrhea; there was no patient who developed valvular heart disease or pulmonary hypertension. These findings support the safety and efficacy of adjunctive fenfluramine as a new treatment option for these patients.