54th Child Neurology Society Annual Meeting in October at the Charlotte Convention Center Coverage

Review 1: Long-term Fenfluramine Shows Sustained Benefits in Dravet and Lennox-Gastaut Syndromes

A comprehensive open-label extension study presented by Schoonjans and colleagues from Antwerp provides important long-term safety and efficacy data for fenfluramine in patients with Dravet syndrome and Lennox-Gastaut syndrome. The research, presented at the Child Neurology Society Annual Meeting, followed 412 patients who had previously participated in fenfluramine clinical trials, offering crucial insights into sustained treatment effects over extended periods.

The study population included 265 patients with Dravet syndrome and 147 with Lennox-Gastaut syndrome, with ages ranging from 2 to over 18 years. Participants continued their established fenfluramine doses from previous studies, with all patients required to maintain at least one concomitant anti-seizure medication. The median treatment duration in this extension study was approximately two years, with overall fenfluramine exposure reaching a median of four years, representing some of the longest follow-up data available for this treatment.

Safety outcomes were reassuring, with no new signals emerging during extended treatment. Common adverse events included coronavirus infection in 20.6% of patients, seizures in 15.3%, and fever in 13.1%. Critically, no cases of valvular heart disease or pulmonary arterial hypertension were observed, addressing key safety concerns associated with fenfluramine’s historical use. Only five patients experienced treatment-related serious adverse events, and three deaths occurred that were deemed unrelated to treatment.

Perhaps most significantly, global functioning assessments demonstrated sustained clinical benefit. Using Clinical Global Impression-Improvement ratings, both investigators and caregivers rated over 93% of patients as improved or showing no change relative to baseline, suggesting that fenfluramine’s benefits persist with long-term use without significant tolerance development.

Reference: Schoonjans AS, Knupp K, Gil-Nagel A, et al. Tolerability and safety of fenfluramine and global functioning of patients in a combined open-label extension study of children and adults with Dravet and Lennox-Gastaut syndromes. Presented at: Child Neurology Society Annual Meeting; October 2025; Charlotte, NC.

Breakthrough Data: 95% of Dravet Syndrome Patients Show Clinical Improvement After 3 Years on Investigational Drug Zorevunersen

SUMMARY: Stoke Therapeutics and Biogen revealed promising long-term results for zorevunersen, an investigational treatment targeting the root cause of Dravet syndrome, a severe childhood epilepsy. New data presented at the 54th Child Neurology Society Annual Meeting demonstrates that 95% of patients experienced improvements in overall clinical status after three years of treatment, with caregivers and clinicians independently reporting similar positive outcomes.

The two-year data showed continuing improvements in cognition and behavior—a stark contrast to natural history studies where patients on standard care alone demonstrated minimal cognitive changes. These results, along with lasting decreases in the number of major motor seizures, suggest that Zorevunersen could change the course of the disease instead of just treating the symptoms

With up to 38,000 people living with Dravet syndrome in the U.S. and EU, and more than 90% continuing to experience seizures despite available treatments, zorevunersen offers new hope. The drug has received FDA Breakthrough Therapy Designation and is currently being evaluated in the Phase 3 EMPEROR study. Safety data across 81 patients showed the treatment was generally well tolerated through three years of follow-up.