Vir Biotechnology, Inc. announced on October 8, 2026, that the U.S. Food and Drug Administration has granted Fast Track designation to VIR-5500. The designation applies to the treatment of late-line metastatic castration-resistant prostate cancer (mCRPC).
VIR-5500 is a PSMA-targeted PRO-XTEN dual-masked T-cell engager (TCE). The company states that the drug is being co-developed through a global strategic collaboration with Astellas Pharma Inc.
The FDA Fast Track designation is intended to facilitate and expedite the development and review of drugs that treat serious conditions and fill an unmet need. According to the filing, VIR-5500 is currently being evaluated in a Phase 1 study across six dose-expansion cohorts. These cohorts include monotherapy arms for patients with taxane-naïve mCRPC and radioligand therapy-naïve or exposed mCRPC, as well as combination regimens with enzalutamide, docetaxel, and darolutamide.
Phase 1 data reported earlier this year indicated that VIR-5500 was generally well tolerated and exhibited promising anti-tumor activity in patients with mCRPC. The company anticipates that Phase 3 trials will begin in 2027.
