Dr. Mary Zupanc with model brain

Investigational Drug Study Leads to FDA Approval for Fenfluramine in Treatment for Dravet Syndrome

Children who experience seizures associated with Dravet syndrome have a new medication option, thanks to research at CHOC Children’s that helped gain the recent approval of the U.S. Food and Drug Administration (FDA).

Dravet syndrome is a sodium channelopathy that causes an intractable, difficult-to-control form of epilepsy beginning in the first year of life, as well as significant developmental and motor impairments. Many patients with this rare and severe type of epilepsy experience prolonged and unrelenting seizures and are at risk for SUDEP (sudden unexpected death in epilepsy).

Dravet syndrome is difficult to treat with the antiepileptic medications currently available in the United States, but the FDA has recently approved FINTEPLA® (fenfluramine) for the treatment of seizures associated with Dravet syndrome in patients 2 years of age and older. Dr. Mary Zupanc, pediatric epileptologist and co-medical director of the CHOC Children’s Neuroscience Institute, was a key investigator in one of the two international drug studies that led to U.S. FDA approval.

Dr. Mary Zupanc
Dr. Mary Zupanc, pediatric epileptologist and co-medical director of the CHOC Children’s
Neuroscience Institute

“The drug we recently trialed, fenfluramine, showed a significant reduction in convulsive seizures and overall seizures, which helped improve the quality of life not only for patients with Dravet but for their families as well,” Dr. Zupanc said.

Study 1 trialed 0.2 mg/kg/day or 0.7 mg/kg/day. The patients on the higher dose had a 70% reduction relative to placebo in monthly convulsive seizure frequency. And 70% of the patients on the higher dose had at least a 50% reduction in their monthly convulsive seizures compared to 7.7% of patients on placebo. Patients on the lower dose of fenfluramine had a 31.7% reduction relative to placebo in monthly convulsive seizure frequency, and 34.2% of patients on the lower dose had at least a 50% reduction in their monthly convulsive seizures.

In addition to reducing the monthly convulsive seizure frequency in patients whose seizures were not adequately controlled on one or more antiepileptic drugs, most study patients responded to treatment with fenfluramine within three to four weeks, and the effects remained consistent over the treatment period. Dr. Zupanc remarked that fenfluramine’s effectiveness could be “life-changing” for patients with Dravet.

Fenfluramine — used on its own and also paired with phentermine in the popular weight-loss combination known as “fen-phen” — was withdrawn from the U.S. market in 1997 after reports of heart valve disease and continued findings of pulmonary hypertension. Due to these risks, subjects received frequent EKGs and echocardiograms throughout the investigational trial. No valve disease or hypertension was found, but a decrease in appetite and some observations of a minor increase in irritability were noted.

Dr. Zupanc is optimistic about fenfluramine’s application for Dravet, but advised that it is only part of an overall treatment plan. “If a physician has a patient with Dravet syndrome, I would make sure the patient gets referred to a Level 4 epilepsy program, the highest designation for epilepsy centers,” Dr. Zupanc said. “CHOC is a level 4 epilepsy center, which means we do investigational drug studies, vagus nerve stimulation, epilepsy surgery, ketogenic diet and provide a full-service epilepsy program with six epileptologists with board-certification in epilepsy. Because we have participated in these [investigational] studies, we are on the ground floor and know how to dose these drugs and adjust these medications.”

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