Assessment of Safety of the Use of Fenfluramine in Children With Dravet Syndrome Under 24 Months of Age

Dravet syndrome is a genetic epilepsy associated with pathogenic variants in SCN1A that codes for Nav1.1, a protein necessary for sodium channels. Children with Dravet syndrome classically present in the first year of life with prolonged seizures, often hemiclonic and in the setting of fever or temperature changes such as getting in or out of bath water. Many anti-seizure medications are sodium channel blockers and exacerbate seizures in this patient population. This creates some limitations in medication choices for this patient population. Recently fenfluramine was approved for use in Dravet syndrome for people 2 years and older. Randomized studies demonstrated a 74.9% reduction of convulsive motor seizures compared to 19.2% in the placebo group. Additionally, 16% of children treated with fenfluramine were seizure free. Fenfluramine is likely to be as effective in children under the age of 2 years. The current study has proposed an intermediate size patient population expanded access protocol to allow access to fenfluramine for children under 24 months of age.