Effect of fenfluramine on seizures and comorbidities in SCN8A-developmental and epileptic encephalopathy: A case series

Ángel Aledo-Serrano*, Borja Cabal-Paz, Elena Gardella, Pablo Gómez-Porro, Otilia Martínez-Múgica, Alvaro Beltrán-Corbellini, Rafael Toledano, Irene García-Morales, Antonio Gil-Nagel

*Corresponding author for this work

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Abstract

SCN8A-developmental and epileptic encephalopathy is caused by pathogenic variants in the SCN8A gene encoding the Nav1.6 sodium channel, and is characterized by intractable multivariate seizures and developmental regression. Fenfluramine is a repurposed drug with proven antiseizure efficacy in Dravet syndrome and Lennox–Gastaut syndrome. The effect of fenfluramine treatment was assessed in a retrospective series of three patients with intractable SCN8A epilepsy and severe neurodevelopmental comorbidity (n = 2 females; age 2.8–13 years; 8–16 prior failed antiseizure medications [ASM]; treatment duration: 0.75–4.2 years). In the 6 months prior to receiving fenfluramine, patients experienced multiple seizure types, including generalized tonic–clonic, focal and myoclonic seizures, and status epilepticus. Overall seizure reduction was 60%–90% in the last 3, 6, and 12 months of fenfluramine treatment. Clinically meaningful improvement was noted in ≥1 non-seizure comorbidity per patient after fenfluramine, as assessed by physician-ratings of ≥“Much Improved” on the Clinical Global Impression of Improvement scale. Improvements included ambulation in a previously non-ambulant patient and better attention, sleep, and language. One patient showed mild irritability which resolved; no other treatment-related adverse events were reported. There were no reports of valvular heart disease or pulmonary arterial hypertension. Fenfluramine may be a promising ASM for randomized clinical trials in SCN8A-related disorders.

Original languageEnglish
JournalEpilepsia Open
Volume7
Issue number3
Pages (from-to)525-531
DOIs
Publication statusPublished - Sep 2022

Bibliographical note

Publisher Copyright:
© 2022 The Authors. Epilepsia Open published by Wiley Periodicals LLC on behalf of International League Against Epilepsy.

Keywords

  • drug repurposing
  • epilepsy
  • genetic epilepsy
  • seizures
  • sodium channelopathy
  • Epilepsies, Myoclonic/drug therapy
  • Fenfluramine/therapeutic use
  • NAV1.6 Voltage-Gated Sodium Channel/genetics
  • Seizures/genetics
  • Comorbidity
  • Humans
  • Child, Preschool
  • Adolescent
  • Female
  • Retrospective Studies
  • Child

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