Biogen Inc.  and Stoke Therapeutics, Inc. announced a collaboration for the development and commercialization of zorevunersen, a potential first-in-class disease modifying medicine in development for the treatment of Dravet syndrome, in all territories outside the United States, Canada, and Mexico. Zorevunersen is an investigational antisense oligonucleotide (ASO) that targets the SCN1A gene, the underlying cause of most cases of Dravet syndrome. Stoke recently announced plans to initiate a global Phase 3 registrational study of zorevunersen (EMPEROR) following successful alignment with regulatory agencies in the United States, Europe, and Japan. The study is on track to initiate in the second quarter of 2025, with a pivotal data readout expected in the second half of 2027, which is anticipated to support global regulatory filings.

Significant unmet treatment needs remain for patients with Dravet syndrome, a severe, genetic developmental and epileptic encephalopathy characterized by severe, recurrent seizures as well as significant cognitive and behavioral impairments. There are no approved disease-modifying therapies for Dravet syndrome, which is difficult to treat and has a poor long-term prognosis. Currently, it is estimated that up to 38,000 people are living with Dravet syndrome in the U.S., UK, EU-4 and Japan.

“With Biogen’s deep experience in neurology and track record of success in commercializing high-value disease-modifying medicines for rare genetic diseases globally, we aim to lead the treatment of Dravet syndrome into a new era by delivering zorevunersen to all patients who could benefit,” said Edward M. Kaye, M.D., Chief Executive Officer of Stoke Therapeutics. “Additionally, this collaboration provides cash flows, that when combined with Stoke’s financial position, support the company through to mid-2028.”

“This collaboration broadens our late-stage pipeline with the addition of a Phase 3-ready disease modifying investigational medicine and allows us to leverage our rare disease product commercialization expertise and global footprint,” said Priya Singhal, M.D., M.P.H., Head of Development at Biogen. “The reductions in seizures in patients already receiving standard of care medicines, together with the improvements in multiple measures of cognition and behavior, demonstrate the potential of zorevunersen as the first disease modifying medicine that addresses the underlying cause of Dravet syndrome.”