VIR-5500

October 8, 2026: Vir Biotechnology (NASDAQ: VIR) said the FDA granted Fast Track designation to VIR-5500, a PSMA-targeted PRO-XTEN dual-masked T-cell engager co-developed with Astellas Pharma, for late-line metastatic castration-resistant prostate cancer (mCRPC).

VIR-5500 is in an open-label, non-randomized Phase 1 trial (NCT05997615) assessing safety, pharmacokinetics, and preliminary efficacy. The study includes monotherapy expansion cohorts in taxane-naïve, radioligand-naïve, and radioligand-exposed mCRPC, plus combination cohorts with enzalutamide in early-line mCRPC, docetaxel in early-line mCRPC, and darolutamide in metastatic hormone-sensitive prostate cancer (mHSPC).

The company said Phase 1 data reported earlier this year showed VIR-5500 was generally well tolerated and showed promising anti-tumor activity in mCRPC. Vir said pivotal Phase 3 trials are anticipated to begin in 2027.

The Fast Track designation is intended to facilitate and expedite development and review for serious conditions with unmet need.