Fenfluramine treatment in pediatric patients with Dravet syndrome reduces seizure burden and overall healthcare costs: A retrospective and observational real-world study

Objectives: Dravet syndrome is a developmental and epileptic encephalopathy characterized by early onset epilepsy with multiple seizure types often intractable to treatment. Randomized clinical trials have demonstrated how treatment with fenfluramine significantly reduces seizure frequency in patients with Dravet syndrome. The study aims to (1) describe the efficacy and tolerability of fenfluramine in a Danish cohort of patients with Dravet syndrome; and (2) evaluate whether treatment with fenfluramine reduces epilepsy-related hospital contacts administrated by pediatricians or epilepsy-trained nurses. Methods: A retrospective registry-based cohort study at the Danish Epilepsy Centre, Filadelfia, Dianalund, Denmark, enrolled 30 pediatric patients with Dravet syndrome treated with fenfluramine between 2017 and 2023. Results: Thirty patients with Dravet syndrome (aged 3-21 years, 12 females) with a verified pathogenic SCN1A variant were included. They were treated with fenfluramine at a mean duration of 29 months with a mean maintenance dose of 0.5 mg/kg/day. The number of patient-years on treatment was 75 years. At last follow-up, 6 patients had discontinued treatment due to lack of efficacy or adverse effects. In the remaining 24 patients, generalized tonic-clonic seizures were reduced by >= 30% in 83%, by >= 50% in 67%, and by 100% in 25%. Additionally, 71% of the patients were reduced in concomitant anti-seizure medication, and 75% experienced a reduction (mean reduction at 52%, range 11%-94%) in epilepsy-related hospital contacts from baseline to the end of the treatment period. Significance: Treatment with fenfluramine effectively reduced seizure frequency and concomitant antiseizure medication in patients with Dravet syndrome. Furthermore, a decrease in epilepsy-related contacts by 80% was observed over 6 years of treatment, which may indicate cost-effective benefits. Plain Language Summary: Patients with Dravet syndrome suffer from severe epileptic seizures that are difficult to treat with medication. Earlier, treatment with fenfluramine (an anti-seizure medication) has been documented to decrease the total number of seizures in patients with Dravet syndrome. This publication summarizes the experiences with fenfluramine in children with Dravet syndrome at the Danish Epilepsy Centre, Filadelfia, Dianalund, Denmark. Our publication also illustrates that treatment with fenfluramine may reduce the patients' number of yearly contacts with doctors and nurses specialized in epilepsy treatment, which may indicate cost-effectiveness.