Stoke Therapeutics and Biogen have dosed the first subject in the global, double-blind Phase III EMPEROR trial of the investigational antisense oligonucleotide, zorevunersen, to treat Dravet syndrome.
The sham-controlled trial is aimed at assessing the safety, tolerability, and efficacy of the therapy in the paediatric population aged between two and 18 years with a confirmed SCN1A gene variant not associated with gain of function.
Go deeper with GlobalData
Discover B2B Marketing That Performs
Combine business intelligence and editorial excellence to reach engaged professionals across 36 leading media platforms.
After an eight-week baseline duration, subjects will be randomised in a 1:1 ratio and given either the therapy or a sham treatment over 52 weeks.
The active treatment arm subjects will be given two 70mg loading doses followed by two 45mg maintenance doses, while all subjects will be receiving standard care medications in the entire trial period.
Change in major motor seizure frequency at week 28 is the trial’s primary endpoint, with key secondary goals including changes in major motor seizure frequency at the mark of week 52 and variations in cognition and behaviour, as per the Vineland-3 subdomain measurement, at week 52.
Following the trial, eligible subjects will have the opportunity to continue treatment with the therapy in an open-label extension trial.
US Tariffs are shifting - will you react or anticipate?
Don’t let policy changes catch you off guard. Stay proactive with real-time data and expert analysis.
By GlobalDataThe EMPEROR study has been commenced in the UK, Japan, and the US, with plans to extend to Europe.
Stoke Therapeutics chief medical officer Barry Ticho said: “Our Phase I/II and open-label extension studies have provided a large dataset to support our understanding of zorevunersen and guide the EMPEROR study design, including dosing, duration and selection and powering of the endpoints.”
Earlier this year, Stoke entered a strategic partnership with Biogen for the development and commercialisation of zorevunersen for Dravet syndrome.
Under the partnership, Stoke maintains exclusive rights in Canada, Mexico, and the US, while Biogen holds exclusive rights to commercialise the therapy in all other global markets.
Dravet syndrome is said to be a developmental and epileptic encephalopathy marked by frequent severe seizures and behavioural and cognitive impairments.
Biogen’s therapeutics development unit head Katherine Dawson said: “Despite treatment with available anti-seizure medicines, no approved medications currently address the underlying cognitive and behavioural aspects of this rare, genetic disease.”
In June 2025, Biogen started dosing in the Phase III BRAVE trial to assess omaveloxolone in children aged between two to 16 years with Friedreich ataxia (FA).
