Zorevunersen Shows Promise in Reducing Seizures for Children with Dravet Syndrome

A new therapy, zorevunersen, is demonstrating significant potential in reducing seizure frequency and improving the quality of life for children and adolescents living with Dravet syndrome. Early clinical trial data suggest this could be a disease-modifying treatment, offering hope for a condition with limited therapeutic options.

Understanding Dravet Syndrome

Dravet syndrome is a rare and severe neurological disorder that begins in infancy. It’s characterized by frequent, prolonged seizures, often triggered by fever and is typically caused by mutations in the SCN1A gene ¹. This gene provides instructions for making a sodium channel, crucial for nerve cell communication. The mutations lead to a deficiency in functional sodium channels, disrupting brain activity.

Children with Dravet syndrome face not only debilitating seizures but also developmental delays, cognitive impairment, and an increased risk of sudden unexpected death in epilepsy (SUDEP) ¹. Current treatments primarily focus on managing seizures with antiseizure medications, but these often provide incomplete control and can have significant side effects.

How Zorevunersen Works

Zorevunersen is an antisense oligonucleotide, a type of drug designed to target the underlying genetic cause of Dravet syndrome. Specifically, it aims to increase the levels of the Nav1.1 sodium channel, which is deficient due to SCN1A mutations ⁴. By boosting the production of this crucial channel, zorevunersen seeks to restore normal brain function and reduce seizure activity.

Clinical Trial Results

Researchers evaluated zorevunersen in two phase 1-2a open-label, multicenter trials – MONARCH and ADMIRAL – involving 81 patients aged 2 to 18 years with Dravet syndrome ¹. 75 patients continued into extension studies. The trials assessed the safety, how the drug moves through the body (pharmacokinetics), and its clinical effects.

Initial results are encouraging. Patients receiving a 70 mg initial dose, followed by doses up to 45 mg, experienced a median reduction in convulsive seizure frequency ranging from 58.82% to 90.91% over the first 20 months ¹. This reduction was consistently observed throughout the study period.

The most common adverse events were mild to moderate. Post-lumbar puncture syndrome was reported in 25% of patients during the initial phase 1-2a studies, and elevated protein levels in cerebrospinal fluid were observed in 45% of patients during the extension studies ¹. There were two deaths reported due to sudden unexpected death in epilepsy and one death due to malnutrition, and one patient experienced a suspected serious adverse reaction leading to study withdrawal.

Future Directions

Zorevunersen, developed in collaboration between Stoke Therapeutics and Biogen ², represents a potentially groundbreaking approach to treating Dravet syndrome by targeting the root genetic cause. Larger, controlled clinical trials are now essential to confirm these promising results, evaluate long-term safety, and determine how zorevunersen can best be integrated into existing treatment plans for children with Dravet syndrome ¹.

Reference

Laux L et al. Zorevunersen in children and adolescents with Dravet Syndrome. New England Journal of Medicine. 2026;394(10):969-82.