Biogen agreed to acquire RayThera in a deal valued at up to $1 billion, adding a portfolio of early-stage immunology assets to the company’s pipeline. RayThera’s co-founders built a small-molecule discovery operation focused on anti-inflammatory programs, and Biogen says the lead candidate is positioned to enter Phase I in early Q3 2026. The acquisition provides an undisclosed upfront payment, with most value tied to future clinical and regulatory milestones. Biogen expects the deal to broaden its immunology footprint beyond its traditional neurology strengths. RayThera completed a $110 million Series A financing in 2025, with investors including Foresite Capital and OrbiMed Advisors. The startup disclosed limited pipeline detail publicly, but the reported target landscape includes commonly pursued immune pathways such as TNF modulation and JAK activity. For Biogen, the purchase arrives after its earlier acquisition of Apellis, signaling a sustained shift toward earlier-stage immunology risk-reduction and portfolio diversification.