VIR-5500

VIR-5500 is an investigational PSMA-targeted PRO-XTEN dual-masked CD3 T-cell engager in Phase 1 development for metastatic prostate cancer. Ongoing cohorts evaluate monotherapy in late-line mCRPC and combination with androgen receptor pathway inhibitors in earlier-line metastatic settings, with potential pivotal Phase 3 trials planned for 2027. It is not approved for marketing.

Drug Class

Investigational PSMA-targeted dual-masked CD3 T-cell engager (TCE)

Approval Status

Investigational (ongoing Phase 1 expansion; no regulatory approval)

Mechanism of Action

Bispecific PSMA/CD3 T-cell engager masked until tumor microenvironment proteases activate it, aiming to direct T cells to kill cancer cells while improving tolerability.