A potential first for a devastating disease, Biogen and Stoke Therapeutics have begun dosing patients in the global Phase 3 EMPEROR trial of zorevunersen.
If successful, this investigational therapy could become the first disease-modifying treatment for Dravet syndrome.
What’s at Stake
Dravet syndrome is:
- A rare, genetic form of epilepsy
- Marked by treatment-resistant seizures and neurodevelopmental impairments
- Caused by mutations in the SCN1A gene
- With no current treatment addressing the root cause
The EMPEROR Study: Quick Facts
- Study goal: Test zorevunersen vs. placebo (“sham”) for safety and effectiveness
- Duration: 52 weeks of treatment after an 8-week baseline period
- Participants: 2–18 years old with confirmed SCN1A mutation (no gain-of-function)
- Locations: U.S., U.K., Japan, with European sites planned
How Zorevunersen Works
Zorevunersen is an antisense oligonucleotide (ASO) — a synthetic RNA molecule designed to restore protein expression and address the underlying genetic defect.
This isn’t just symptom control. It’s aiming at the root cause.
Study Design
Randomization: 1:1 ratio — zorevunersen or sham
Dosing plan:
- Two 70 mg loading doses (Day 1, Week 8)
- Two 45 mg maintenance doses (Week 24, Week 40)
All participants will keep taking their standard-of-care seizure medications.
Primary and Secondary Goals
Primary endpoint:
- Change in major motor seizure frequency at Week 28
Key secondary endpoints:
- Change in seizure frequency at Week 52
- Improvements in behavior and cognition using Vineland-3 measures:
- Expressive & receptive communication
- Interpersonal relationships
- Coping and personal skills
Why Experts Are Watching
“The potential to address the underlying genetic cause and also improve neurodevelopmental symptoms signals a fundamentally new way of treating the disease.”
- Dr. Joseph Sullivan, UCSF
Phase 1/2 and extension studies have already shown:
- Durable seizure reduction
- Ongoing cognitive and behavioral improvements
That’s why there’s high enrollment interest for EMPEROR.
What’s Next
- The trial is already underway in the U.S., U.K., and Japan.
- European sites will follow.
- Eligible participants can roll over into an open-label extension to keep receiving zorevunersen after the study.
Bottom line:
If EMPEROR succeeds, Dravet syndrome patients and their families may finally have a therapy that goes beyond seizure control, tackling the root cause and improving quality of life.
