Stoke and Biogen Show Long-Term Data Supporting Zorevunersen’s Disease-Modifying Potential in Dravet Syndrome — Stoke Therapeutics, Inc.

Event summary

Stoke Therapeutics and Biogen presented long-term clinical data at the 16th European Epilepsy Congress (EEC) supporting zorevunersen’s potential as a disease-modifying treatment for Dravet syndrome.
Four-year open-label extension (OLE) results showed substantial and durable reductions in seizures and continuing improvements in cognition and behavior.
A new exploratory sub-analysis demonstrated substantial reductions in severe seizure types, which are the leading risk factor for sudden unexpected death in epilepsy (SUDEP).
The global, pivotal Phase 3 EMPEROR study is underway, with a data readout anticipated in the third quarter of 2027 to support a rolling New Drug Application (NDA) submission to the FDA in the second half of 2027.

The big picture

The long-term data presented at the EEC reinforce zorevunersen’s potential as a first-in-class disease-modifying treatment for Dravet syndrome, a severe developmental and epileptic encephalopathy with limited therapeutic options. The strategic collaboration between Stoke Therapeutics and Biogen aims to address the unmet needs of patients with Dravet syndrome, leveraging RNA medicine to restore protein expression. The upcoming Phase 3 data readout and potential NDA submission will be critical milestones in the development of zorevunersen, with implications for the broader rare disease and neurology markets.

What we're watching

Regulatory Pathway: Whether the Phase 3 EMPEROR study results will support a successful rolling NDA submission to the FDA in the second half of 2027.
Commercialization Strategy: How Stoke and Biogen will navigate the commercialization of zorevunersen, given Biogen’s exclusive rest-of-world rights and Stoke’s exclusive rights in the U.S., Canada, and Mexico.
Long-Term Safety: The ongoing monitoring of zorevunersen’s long-term safety and tolerability, particularly given the elevated CSF protein lab values observed in approximately 94% of patients.