December 1, 2025 — Leads & Copy — Stoke Therapeutics, Inc. and Biogen Inc. will present data from studies of zorevunersen at the 2025 American Epilepsy Society (AES) Annual Meeting, taking place December 5-9 in Atlanta, Georgia.
Zorevunersen, an investigational antisense oligonucleotide, is being evaluated as a potential first-in-class medicine for the treatment of Dravet syndrome. Dravet syndrome is a severe developmental and epileptic encephalopathy (DEE) characterized by recurrent seizures and significant cognitive and behavioral impairments.
The data to be presented at AES will include new propensity weighted analyses derived from four years of clinical data from the Phase 1/2a and ongoing open-label extension (OLE) studies of zorevunersen. The pivotal Phase 3 EMPEROR study is also currently evaluating zorevunersen in children and adolescents with Dravet syndrome.
Dr. Barry Ticho, Chief Medical Officer of Stoke Therapeutics, said the four years of data show substantial and durable effects on seizures, behavior and cognition. He added that the ability to compare directly to natural history data allows Stoke to more fully appreciate the disease-modifying potential of zorevunersen for the treatment of Dravet syndrome. Ticho said he looks forward to discussing the latest findings with epilepsy experts at AES.
Dr. Katherine Dawson, Head of the Therapeutics Development Unit at Biogen, said the new EEG data at AES highlight the effects of zorevunersen in decreasing abnormal brain activity that is persistently higher in patients with Dravet syndrome. Dawson added that exploratory analyses showed that a reduction in abnormal brain EEG activity was associated with an increased probability of achieving a reduction in major motor seizure frequency.
Details of the presentations at AES are as follows:
- Title: Zorevunersen Continues to Demonstrate Potential as a Disease-modifying Therapy in Long-term Open-label Extension Studies of Patients with Dravet Syndrome
- Oral Presentation Date & Time: Friday, December 5, 3:30-5:55 PM EST
- Oral Presenter: M. Scott Perry, M.D., Head of Neurosciences and Director of the Jane and John Justin Institute for Mind Health and Medical Director of Neurology at the Genetic Epilepsy Clinic at Cook Children’s
- Title: Zorevunersen Demonstrates Disease-modifying Potential in Patients with Dravet Syndrome with Increases in Seizure-free Days, Improvements in Quality of Life, and Benefits in Overall Functioning
- Poster Presentation Date & Time: Saturday, December 6, 12:00-2:00 PM EST
- Poster Presenter: Kelly Knupp, M.D., MSCS, Professor of Pediatrics and Neurology at the University of Colorado Anschutz and the Dravet Program Director and Epilepsy Program Lead at Children’s Hospital Colorado
- Poster Number: 1.379
- Title: Electrophysiological Improvements in Patients with Dravet Syndrome Following Treatment with Zorevunersen, an Investigational Antisense Oligonucleotide
- Poster Presentation Date & Time: Monday, December 8, 12:00-1:45 PM EST
- Poster Presenter: Nigel Colenbier, Senior Data Scientist, Epilog, Clouds of Care
- Poster Number: 3.489
- Title: Spectral Electroencephalogram Abnormalities Across Development in Patients with Dravet Syndrome
- Poster Presentation Date & Time: Sunday, December 7, 12:00-2:00 PM EST
- Poster Presenter: Pieter van Mierlo, Founder and Chief Scientific Officer, Epilog, Clouds of Care, Associate Professor, Ghent University
- Poster Number: 2.432
Dravet syndrome is often caused by mutations in the SCN1A gene, leading to insufficient levels of NaV1.1 protein in neuronal cells in the brain. Even when treated with the best available anti-seizure medicines (ASMs), up to 57% of patients do not achieve ≥50% reduction in seizure frequency. Developmental and cognitive impairments often include intellectual disability, developmental delays, movement and balance issues, language and speech disturbances, growth defects, sleep abnormalities, disruptions of the autonomic nervous system and mood disorders.
People living with Dravet syndrome have a higher risk of sudden unexpected death in epilepsy, or SUDEP; up to 20% of children and adolescents with Dravet syndrome die before adulthood due to SUDEP, prolonged seizures, seizure-related accidents or infections. It is estimated that up to 38,000 people are living with Dravet syndrome in the U.S. (~16,000), UK, EU-4 and Japan. There are no approved disease-modifying therapies for people living with Dravet syndrome.
Zorevunersen is designed to treat the underlying cause of Dravet syndrome by increasing functional NaV1.1 protein production in brain cells from the non-mutated (wild-type) copy of the SCN1A gene. The FDA has granted zorevunersen orphan drug designation, rare pediatric disease designation and Breakthrough Therapy Designation for the treatment of Dravet syndrome. Stoke and Biogen have a strategic collaboration to develop and commercialize zorevunersen for Dravet syndrome.
The EMPEROR Phase 3 Study (NCT06872125) is evaluating the efficacy, safety, and tolerability of zorevunersen in children ages 2 to <18 with Dravet syndrome. Participants will be randomized 1:1 to receive either zorevunersen via intrathecal administration or a sham comparator for a 52-week treatment period following an 8-week baseline period. The primary endpoint is percent change from baseline in major motor seizure frequency at week 28.
For more information about the EMPEROR study, visit https://www.emperorstudy.com/.
Stoke Therapeutics (Nasdaq: STOK) is dedicated to restoring protein expression by harnessing the body’s potential with RNA medicine. Stoke’s initial focus are diseases of the central nervous system and the eye that are caused by a loss of ~50% of normal protein levels (haploinsufficiency). Stoke is headquartered in Bedford, Massachusetts.
Biogen, founded in 1978, pioneers innovative science to deliver new medicines to transform patients’ lives and to create value for shareholders and communities. Biogen applies deep understanding of human biology and leverages different modalities to advance first-in-class treatments or therapies that deliver superior outcomes. Biogen routinely posts information that may be important to investors on its website at www.biogen.com. Follow Biogen on social media – Facebook, LinkedIn, X, YouTube.
References:
1 Symonds, J. et al. Early childhood epilepsies: epidemiology, classification, aetiology, and socio-economic determinants. Brain. 2021;144(9):2879-2891.
2 Based on Stoke Therapeutics’ preliminary estimates, which scaled annual incidence to prevalence using country-specific live birth rates over the past 85 years and adjusted for Dravet-specific mortality. The estimate is based on incidence rates published by Wu et al., Pediatrics, 2015.
Contact: Catherine Owen, Stoke Therapeutics, catherine.owen@stoketherapeutics.com, 617-580-2903
Source: Stoke Therapeutics
