In a significant pharmaceutical industry deal announced Tuesday, Biogen has secured exclusive rights to commercialize zorevunersen, a promising experimental treatment for Dravet syndrome, outside of North America. The agreement, valued at $165 million upfront, gives Biogen access to what could become the first therapy of its kind for this rare form of epilepsy.
Under the terms of the collaboration with Stoke Therapeutics, Biogen will gain commercialization rights in markets beyond the United States, Canada, and Mexico. The companies will share external development costs at a 70-30 split, with potential additional payments to Stoke of up to $385 million tied to various development and commercial milestones. The deal also includes provisions for Biogen to potentially license similar follow-on products.
Zorevunersen, currently preparing to enter Phase 3 clinical trials this year, represents a new approach to treating Dravet syndrome. The drug, classified as an antisense oligonucleotide, works by targeting specific RNA sequences to boost the expression of a crucial sodium channel protein linked to the condition. Results from this pivotal study are anticipated in 2027.
The acquisition aligns with Biogen’s strategic needs, as the company faces declining revenue from its established products, including Spinraza and its multiple sclerosis portfolio. CEO Christopher Viehbacher has actively pursued external opportunities since taking the helm in late 2022, including the $7.3 billion acquisition of Reata Pharmaceuticals and a $1.2 billion deal for HI-Bio.
Market analysts view the deal favorably, with Stifel’s Paul Matteis noting the strategic fit within Biogen’s existing rare disease portfolio, which includes Spinraza and Skyclarys. The relatively modest upfront payment could prove advantageous if zorevunersen achieves its commercial potential.
However, success is not guaranteed. Physician feedback indicates demanding efficacy requirements for the drug’s approval. A TD Cowen survey of 25 epilepsy specialists found 60% considered zorevunersen promising compared to current Dravet syndrome treatments, though concerns exist about its intravenous administration in a market dominated by oral medications.
Recent clinical data has shown promise, with a small study
demonstrating superior seizure reduction at high doses compared to placebo in Dravet syndrome patients. The company has secured agreement with regulators in the United States, Europe, and Japan regarding the design of its upcoming Phase 3 trial.
The market opportunity is significant, with Biogen estimating Dravet syndrome affects up to 38,000 people across major markets including the U.S., U.K., Japan, and several European countries. However, pricing challenges may emerge in non-U.S. markets, where other seizure medications have faced reimbursement difficulties.
Investors responded cautiously to the announcement, with Biogen’s stock remaining largely stable in morning trading. While the deal represents a strategic expansion of Biogen’s rare disease portfolio, analysts suggest it’s unlikely to significantly impact the company’s near-term financial outlook.
The collaboration capitalizes on growing interest in genetic medicines targeting neurological conditions. Sodium channels, the target of zorevunersen, have long attracted attention as potential therapeutic targets for various conditions including epilepsy, pain, and mood disorders. The agreement reflects broader industry trends toward developing precise, genetically-targeted treatments for rare diseases, while highlighting the ongoing challenge of balancing scientific innovation with commercial viability in the pharmaceutical sector.