Breakthrough Long-Term Data For Zorevunersen Marks Major Milestone In Dravet Syndrome Treatment

Stoke Therapeutics and Biogen have unveiled compelling long-term evidence from their Phase 1/2a trial and subsequent open-label extension study, demonstrating the sustained therapeutic impact of zorevunersen in managing Dravet syndrome—a severe, rare-onset form of childhood epilepsy characterized by frequent, treatment-resistant seizures.

Clinical Results Show Sustained Benefits Across Multiple Outcomes

When combined with conventional anti-seizure medications, zorevunersen delivered meaningful reductions in seizure frequency while expanding the number of seizure-free days among trial participants. Beyond seizure control, the therapy demonstrated measurable enhancements in cognitive function, behavioral markers, and patients’ day-to-day quality of life—outcomes that extend well beyond traditional seizure metrics in pediatric epilepsy treatment.

Dravet Syndrome: Why This Treatment Matters

Dravet syndrome represents one of the most challenging forms of early-onset epilepsy, typically emerging during infancy and frequently proving resistant to multiple anti-seizure drugs. The progressive nature of the condition often leads to developmental delays and reduced life expectancy, making new therapeutic options critical for affected patients and families.

Recognition at Major Medical Conference

These findings were presented at the 2025 American Epilepsy Society Annual Meeting held in Atlanta, Georgia, positioning both companies’ work within the broader conversation on emerging treatments for rare neurological conditions. The data supports the potential for zorevunersen as an adjunctive therapy in this historically difficult-to-treat patient population.

The presentation underscores the evolving landscape of precision medicine approaches to rare seizure disorders, with long-term safety and efficacy data providing important guidance for clinical development pathways moving forward.