Biogen Inc. (Nasdaq: BIIB) and RayThera Inc., a private biotechnology company focused on discovering and developing small molecule therapies in immunology,  announced the companies have entered into a definitive agreement under which Biogen has agreed to acquire RayThera Inc. for up to $1 billion, consisting of an upfront payment and, predominantly, payments contingent on the achievement of future clinical and regulatory milestones.

RayThera’s portfolio includes multiple anti-inflammatory assets that could potentially treat immune-mediated conditions across a range of indications. The lead candidate is expected to enter Phase 1 development in early Q3 2026.

“With this acquisition, we are further deepening our pipeline in immunology by adding a suite of assets that can allow us to expand into new disease areas,” said Priya Singhal, M.D., M.P.H., Executive Vice President and Head of Development at Biogen. “We believe these assets can meaningfully contribute to our long-term pipeline potential and we’re excited about the opportunity to rapidly advance the first candidate into the clinic.”

“With its strong global development capabilities in immunology, we believe that Biogen is the natural fit to move these assets forward into Phase 1 development and beyond,” said Qing Dong, co-founder, Chairman and CEO of RayThera. “I am proud of our team at RayThera for the innovative pipeline we have built together and the rapid advancement of these molecules.”

Financial Details and Terms of the Transaction
Under the terms of the agreement, Biogen will make an upfront payment to RayThera’s shareholders, who would also be eligible for clinical and regulatory milestone payments for a total potential deal value of up to $1 billion. The transaction is subject to customary closing conditions, including receipt of necessary regulatory approvals and is currently anticipated to close in the third quarter of 2026. With the acquisition, once closed, Biogen will lead development, manufacturing and global commercialization of these assets.