SERT x 5-HT1D receptor x σ1 receptor x 5-HT2C receptor x 5-HT2A receptor

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 a treatment protocol to allow access to fenfluramine for children under 24 months of age.

The primary purpose of this study is evaluate the safety and tolerability of fenfluramine hydrochloride (HCl) 0.2 to 0.8 mg/kg/day in infants 1 year to less than 2 years of age with Dravet syndrome.

This is a phase II clinical trial in which children with refractory infantile spasms (also called epileptic spasms or West syndrome) will be treated with fenfluramine, to evaluate efficacy, safety, and tolerability. Patients with infantile spasms that have not responded to treatment with vigabatrin and ACTH we will be invited to participate. Study participants will undergo baseline video-EEG, receive treatment with fenfluramine for 21 days, and then undergo repeat video-EEG to determine effectiveness. Patients with favorable response will have the opportunity to continue treatment for up to 6 months.