New NEJM data show zorevunersen significantly reduced seizures and improved neurodevelopmental outcomes in Dravet syndrome patients. Phase 3 EMPEROR trial results expected in 2027
Written By: Nikita Jha, BPharm
Reviewed By: Pharmacally Editorial Team
Stoke Therapeutics and Biogen have reported encouraging clinical data for zorevunersen, an investigational therapy targeting the genetic cause of Dravet Syndrome. Results from Phase 1/2a and ongoing open-label extension studies were published in the New England Journal of Medicine, showing sustained seizure reduction and improvements in neurodevelopmental outcomes.
Zorevunersen is an antisense oligonucleotide designed to increase expression of the SCN1A gene, the primary genetic driver of Dravet syndrome. By restoring SCN1A protein levels, the therapy aims to address the underlying biology of the disease rather than simply controlling seizures.
The studies enrolled 81 children and adolescents aged 2–18 years with refractory Dravet syndrome receiving standard anti-seizure medications. Patients received single or multiple intrathecal doses up to 70 mg, followed by continued treatment in open-label extension studies with dosing approximately every four months.
Patients receiving initial 70 mg doses experienced the greatest benefit, with median major motor seizure frequency declining substantially from baseline. In some patients, seizure reductions reached up to 91% during long-term follow-up, with improvements sustained for as long as three years. Investigators also observed increases in seizure-free days compared with natural history data, suggesting durable treatment effects.
Exploratory analyses using the Vineland-3 adaptive behavior scale showed improvements in communication, motor skills, socialization, and daily living abilities. Caregiver and clinician assessments also indicated better overall functioning and quality of life.
Across more than 800 administered doses, zorevunersen was generally well tolerated. The most common laboratory finding was elevated cerebrospinal fluid protein, reported in 44% of patients in extension studies, typically without symptoms. One patient discontinued treatment due to this finding.
The therapy is now being evaluated in the Phase 3 EMPEROR trial, a randomized study enrolling approximately 150 patients. The trial will assess reduction in major motor seizure frequency over 28 weeks, with additional neurodevelopmental outcomes. Enrollment is expected to complete in Q2 2026, with topline results anticipated in mid-2027, which could support a future FDA New Drug Application.
Reference
The New England Journal of Medicine Publishes First Data to Demonstrate the Potential for Disease Modification in Dravet Syndrome, 04 March 2026, The New England Journal of Medicine Publishes First Data to Demonstrate the Potential for Disease Modification in Dravet Syndrome | Biogen
Linda Laux et al, Zorevunersen in Children and Adolescents with Dravet Syndrome, N Engl J Med 2026;394:969-982, Vol. 394 No. 10, Zorevunersen in Children and Adolescents with Dravet Syndrome | New England Journal of Medicine
The New England Journal of Medicine Publishes First Data to Demonstrate the Potential for Disease Modification in Dravet Syndrome, 04 March 2026, https://investor.stoketherapeutics.com/news-releases/news-release-details/new-england-journal-medicine-publishes-first-data-demonstrate
About Writer
Nikita Jha BPharm
She is a pharmacy graduate with expertise in clinical research, pharmacovigilance, and medical writing. In her words, she is passionate about translating complex scientific data into clear, accurate healthcare communications that advance drug safety and patient care.