Vir Biotechnology’s VIR-5500 gets FDA Fast Track for prostate cancer

SAN FRANCISCO--()--October 08, 2026-- Vir Biotechnology, Inc. (Nasdaq: VIR) today announced that the U.S. Food and Drug Administration (FDA) granted Fast Track designation to VIR-5500, a PSMA-targeted PRO-XTEN(R) dual-masked T-cell engager (TCE), for the treatment of late-line metastatic castration-resistant prostate cancer (mCRPC). VIR-5500 is being co-developed by Astellas Pharma Inc. and Vir Biotechnology through a global strategic collaboration. "Receiving Fast Track designation reflects the potential of VIR-5500 to address an area of serious unmet need in late-line mCRPC and the strong momentum we have achieved with Astellas as we prepare to enter pivotal Phase 3 development in 2027," said Marianne De Backer, President and Chief Executive Officer of Vir Biotechnology. "We look forward to working with the FDA to rapidly advance the development of VIR-5500 for people living with mCRPC." "People living with advanced prostate cancer need new treatment options that can offer meaningful and durable benefit," said Moitreyee Chatterjee-Kishore, Executive Vice President and Head of Oncology Development, Astellas. "This Fast Track designation reinforces the importance of advancing VIR-5500 with urgency, and we are committed to exploring its potential to make a meaningful difference for patients and their families." FDA Fast Track designation is intended to facilitate and expedite the development and review of drugs to treat serious conditions and fill an unmet need. VIR-5500 is being evaluated in a Phase 1 study across six dose-expansion cohorts. The monotherapy dose-expansion cohorts include patients with taxane naïve mCRPC, radioligand therapy naïve mCRPC and radioligand therapy exposed mCRPC. The combination regimen dose-expansion cohorts include VIR-5500 in combination with enzalutamide in early-line mCRPC, VIR-5500 in combination with docetaxel in early-line mCRPC and VIR-5500 in combination with darolutamide in metastatic hormone sensitive prostate cancer (mHSPC). Phase 1 data reported earlier this year showed VIR-5500 was generally well tolerated and exhibited promising anti-tumor activity in patients with mCRPC. Phase 3 trials are anticipated to begin in 2027. About VIR-5500 T-cell engagers (TCEs) are powerful anti-tumor agents that can direct the immune system, specifically T-cells, to destroy cancer cells. VIR-5500 is an investigational PRO-XTEN(R) dual-masked TCE currently being evaluated in an open-label, non-randomized Phase 1 clinical trial (NCT05997615) designed to assess the safety, pharmacokinetics and preliminary efficacy in participants with metastatic castration-resistant prostate cancer (mCRPC). VIR-5500 combines a bispecific PSMA and CD3 binding TCE with the PRO-XTEN(R) masking technology. The PRO-XTEN(R) masking technology is designed to keep the TCEs inactive (or masked) until they reach the tumor microenvironment, where tumor-specific proteases cleave off the mask and activate the TCEs, enabling killing of cancer cells