Biogen and Stoke Start Phase 3 Dravet Study as GT Biopharma Trial Advances

Biogen and Stoke Therapeutics have begun dosing participants in the global Phase 3 EMPEROR study of zorevunersen, an investigational antisense oligonucleotide designed to modify the course of Dravet syndrome. The first patient received treatment on 11 August, marking the transition of the programme into its pivotal stage. The double-blind trial plans to enrol children aged two to under 18 who carry SCN1A loss-of-function variants and will compare two loading and two maintenance intrathecal doses of zorevunersen with a sham procedure over 52 weeks, following an eight-week baseline period. The primary measure is the percentage change in major motor seizure frequency at Week 28, with secondary endpoints spanning seizure reduction through Week 52 and cognitive and behavioural assessments. If successful, zorevunersen could become the first therapy to address the underlying genetic cause of Dravet syndrome, a rare epilepsy for which current treatments largely manage symptoms only. Separately, GT Biopharma reported that its Phase 1 dose-escalation study of GTB-3650, a second-generation TriKE natural-killer-cell engager for relapsed or refractory CD33-positive blood cancers, has advanced to Cohort 3 after an independent safety review found no tolerability issues in the first two cohorts. Early biomarker data from the initial four patients showed heightened NK-cell activity, and preliminary results from the trial are expected later in 2025.