Astellas Pharma and Vir Biotechnology struck a co‑development and co‑commercialization agreement focused on VIR‑5500, a masked T‑cell engager (TCE) targeting PSMA for prostate cancer. The deal carries up to $1.7 billion in potential value and pairs Vir’s PRO‑XTEN masking technology, designed to reduce off‑tumor toxicity, with Astellas’ development and commercialization infrastructure. VIR‑5500 is in Phase I; the collaboration accelerates clinical plans to evaluate safety and therapeutic index in PSMA‑expressing tumors.