The partnership splits the rights to Stoke’s epilepsy antisense oligonucleotide, with up to $385 million in potential payments due to Stoke.
Biogen’s leadership has said they aren’t eager to deal, but turns out Stoke Therapeutics had a little something in its rare disease catalog that prompted Biogen to strike. The companies will work on a Dravet syndrome treatment under a deal worth $165 million upfront.
Stoke is also eligible for $385 million in total payments in development and commercial milestones, plus royalties on future sales, according to a Tuesday announcement.
Stoke will keep global development rights of the drug, called zorevunersen, and commercialization rights in North America. Biogen will get commercialization rights in the rest of the world.
Stoke CEO Edward Kaye said the deal stretches the biotech’s runway through to mid-2028. Stoke is planning to put zorevunersen into a Phase III EMPEROR trial starting mid-2025.
Dravet is a severe, genetic form of epilepsy that can cause prolonged seizures and cognitive dysfunction. Most cases are caused by a mutation in a single gene, SCN1A, that causes haploinsufficiency of a NaV1.1 sodium ion channel. Zorevunersen is an anti-sense oligonucleotide that Stoke hopes will treat the underlying insufficiency. Current treatments for Dravet are a patient-to-patient mix of different anti-seizure medications, some of which can even exacerbate seizures.
“Strategically, it’s very easy to see why Biogen sees this drug as a logical fit within their portfolio with Spinraza and Skyclarys, and the upfront payment is pretty modest relative to what zorevunersen could sell in a bull case (hundreds of millions),” analysts at Stifel, referring to Biogen’s rare disease medicines, wrote in a note to investors.
The deal comes shortly after Biogen made public statements at the J.P. Morgan 2025 conference and in a fourth quarter earnings call resisting pressure to start dealmaking, with the company’s stock falling to a five-year low in January.
“The one thing [a deal] has to do is make financial sense,” said Biogen’s CEO Chris Viehbacher on the company’s 2024 Q4 earnings call. “I think where we are as a company, we don’t need to be taking a huge amount of risk on acquisitions. That said, we are always looking. We always have about at least 15 to 20 different projects that we’re looking at, at any one time.”
In addition to this new Stoke deal, Biogen recently submitted an unsolicited offer to buy its long-time partner Sage Therapeutics, though this led to a lawsuit and ultimate rejection by Sage.
