Stoke Therapeutics Partners with Biogen on Epilepsy Drug

Stoke Therapeutics has entered into a collaboration with Biogen on the development and commercialization of zorevunersen, a potential first-in-class treatment for a form of epilepsy known as Dravet syndrome. Zorevunersen is an investigational antisense oligonucleotide (ASO) that targets the SCN1A gene, the underlying cause of most cases of Dravet syndrome.

Upon closing of the transaction, Stoke will receive an upfront payment of $165 million. Additionally, Stoke may receive up to $385 million in development and commercial milestone payments. Stoke will also be eligible to receive tiered royalties ranging from low double digits to high teens on potential net sales in the Biogen territory.

Stoke will continue to lead global development and retains exclusive development and commercialization rights for zorevunersen in the United States, Canada, and Mexico. Biogen receives exclusive rights to commercialize zorevunersen in the rest of the world. Stoke has also granted Biogen an option to license rights outside of the United States, Canada, and Mexico to certain future follow-on ASO products targeting SCN1A, in exchange for separate milestone, cost sharing, and royalty considerations.

Dravet syndrome is 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 US, UK, EU-4 and Japan.

Zorevunersen has been granted orphan drug designation by the FDA and the EMA based on its demonstrated potential for disease modification in the form of Dravet syndrome associated with the SCN1A gene. The FDA has also granted zorevunersen rare pediatric disease designation and Breakthrough Therapy Designation for a second form of Dravet syndrome.

“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…,” said Stoke Therapeutics CEO Edward M. Kaye. “Additionally, this collaboration provides cash flows, that when combined with Stoke’s financial position, support the company through to mid-2028.” (Source: Stoke Therapeutics Website, 18 February, 2025)