Article,
Effect of fenfluramine on seizures and comorbidities in SCN8A-developmental and epileptic encephalopathy: A case series
Affiliations
- [1] Ruber Int Hosp, Neurol Dept, Epilepsy Program, La Maso 38, Madrid, Spain [NORA names: Spain; Europe, EU; OECD];
- [2] Puerta Hierro Univ Hosp, Neurol Dept, Madrid, Spain [NORA names: Spain; Europe, EU; OECD];
- [3] Danish Epilepsy Ctr, ERN EpiCARE, Dept Epilepsy Genet & Personalized Treatment, Dianalund, Denmark [NORA names: Filadelfia - Danish Epilepsy Hospital; Hospital; Denmark; Europe, EU; Nordic; OECD];
- [4] Univ Southern Denmark, Odense, Denmark [NORA names: SDU University of Southern Denmark; University; Denmark; Europe, EU; Nordic; OECD];
- [5] Donostia Univ Hosp, Pediat Neurol Sect, Pediat Dept, San Sebastian, Spain [NORA names: Spain; Europe, EU; OECD];
(... more)
Abstract
SCN8A-developmental and epileptic encephalopathy is caused by pathogenic variants in the SCN8A gene encoding the Na(v)1.6 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.