Biogen has entered into a definitive agreement to acquire RayThera, a biotechnology company focused on developing small-molecule therapies for immunological disorders, in a transaction valued at up to USD 1 billion.

The deal includes an upfront payment to RayThera shareholders, with the majority of the consideration tied to future clinical and regulatory milestones. The acquisition is expected to bolster Biogen’s immunology portfolio and expand its presence in new disease areas.

RayThera has developed a pipeline of anti-inflammatory therapies designed to treat a range of immune-mediated conditions. Its lead candidate is expected to enter Phase 1 clinical trials in early third quarter of 2026, marking an important step in the development of the company’s research programme.

Biogen said the acquisition aligns with its strategy of strengthening its long-term research and development pipeline. The company believes RayThera’s assets have the potential to address unmet medical needs in immunology while complementing its existing expertise in developing therapies for complex diseases.

Priya Singhal, Executive Vice President and Head of Development at Biogen, said the acquisition would deepen the company’s immunology pipeline and provide opportunities to expand into additional therapeutic areas. She added that Biogen intends to rapidly advance the lead candidate into clinical development.

RayThera leadership welcomed the agreement, highlighting Biogen’s global development capabilities and experience in immunology as key factors in advancing the company’s drug candidates through clinical testing and commercialiSation.

Under the terms of the transaction, Biogen will assume responsibility for the development, manufacturing and global commercialization of RayThera’s assets once the deal closes. The agreement remains subject to customary closing conditions, including regulatory approvals, and is expected to be completed during the third quarter of 2026.

The acquisition reflects continued investment in immunology research as biotechnology companies seek to develop next-generation therapies for chronic inflammatory and immune-mediated diseases.