Efficacy and safety of Fenfluramine hydrochloride for the treatment of seizures in Dravet syndrome: A real-world study

Epilepsia. 2020 Nov;61(11):2405-2414. doi: 10.1111/epi.16690. Epub 2020 Sep 18.

Abstract

Objective: Dravet syndrome (DS) is a drug-resistant, infantile onset epilepsy syndrome with multiple seizure types and developmental delay. In recently published randomized controlled trials, fenfluramine (FFA) proved to be safe and effective in DS.

Methods: DS patients were treated with FFA in the Zogenix Early Access Program at four Italian pediatric epilepsy centers. FFA was administered as add-on, twice daily at an initial dose of 0.2 mg/kg/d up to 0.7 mg/kg/d. Seizures were recorded in a diary. Adverse events and cardiac safety (with Doppler echocardiography) were investigated every 3 to 6 months.

Results: Fifty-two patients were enrolled, with a median age of 8.6 years (interquartile range [IQR] = 4.1-13.9). Forty-five (86.5%) patients completed the efficacy analysis. The median follow-up was 9.0 months (IQR = 3.2-9.5). At last follow-up visit, there was a 77.4% median reduction in convulsive seizures. Thirty-two patients (71.1%) had a ≥50% reduction of convulsive seizures, 24 (53.3%) had a ≥75% reduction, and five (11.1%) were seizure-free. The most common adverse event was decreased appetite (n = 7, 13.4%). No echocardiographic signs of cardiac valvulopathy or pulmonary hypertension were observed. There was no correlation between type of genetic variants and response to FFA.

Significance: In this real-world study, FFA provided a clinically meaningful reduction in convulsive seizure frequency in the majority of patients with DS and was well tolerated.

Keywords: Dravet syndrome; SCN1A; childhood epilepsy; convulsive seizures; fenfluramine.

Publication types

  • Multicenter Study
  • Pragmatic Clinical Trial

MeSH terms

  • Adolescent
  • Adult
  • Anorexia / chemically induced
  • Anticonvulsants / administration & dosage
  • Anticonvulsants / adverse effects
  • Child
  • Child, Preschool
  • Epilepsies, Myoclonic / diagnostic imaging
  • Epilepsies, Myoclonic / drug therapy*
  • Epilepsies, Myoclonic / physiopathology
  • Female
  • Fenfluramine / administration & dosage*
  • Fenfluramine / adverse effects
  • Follow-Up Studies
  • Humans
  • Male
  • Prospective Studies
  • Seizures / diagnostic imaging
  • Seizures / drug therapy*
  • Seizures / physiopathology
  • Selective Serotonin Reuptake Inhibitors / administration & dosage*
  • Selective Serotonin Reuptake Inhibitors / adverse effects
  • Treatment Outcome
  • Young Adult

Substances

  • Anticonvulsants
  • Serotonin Uptake Inhibitors
  • Fenfluramine