Astellas Pharma and Vir Biotechnology struck a global co‑development agreement worth up to $1.37 billion plus near‑term payments to advance VIR‑5500, a PRO‑XTEN dual‑masked CD3 T‑cell engager targeting PSMA in prostate cancer. The collaboration includes cash, equity investment and milestone and royalty provisions. The deal accelerates Vir’s oncology pivot and gives Astellas access to a masked engager designed to reduce off‑tumor toxicity. Company releases noted near‑term payments and sizeable downstream milestones, while both firms signalled coordinated global development and regulatory plans.