Vir Biotechnology press releases and clinical trial registries

Vir Biotechnology's VIR-5818 and VIR-5500 Show Promising Results in Phase 1 Cancer Trials

Jan 8, 2025, 01:58 PM

Vir Biotechnology, Inc. has announced encouraging preliminary safety and efficacy data from ongoing Phase 1 dose escalation trials for its dual-masked T-cell engagers, VIR-5818 and VIR-5500. VIR-5818, targeting various HER2-expressing solid tumors, showed tumor shrinkage in 50% of participants receiving doses ≥400 µg/kg, with confirmed partial responses in 33% of participants with HER2-positive colorectal cancer (CRC). VIR-5500, targeting PSMA in metastatic castration-resistant prostate cancer (mCRPC), demonstrated PSA declines in 100% of participants and PSA50 responses in 58% of participants at doses ≥120 µg/kg. Both candidates exhibited a promising safety profile with no dose-limiting cytokine release syndrome observed, and no grade 3 CRS reported. The maximum tolerated dose has not yet been reached for either drug, and Vir Biotechnology is evaluating a Q3W dosing regimen for both. Vir Biotechnology is leveraging its PRO-XTEN™ masking technology to enable selective activation of these T-cell engagers in the tumor microenvironment, potentially reducing toxicity and expanding the therapeutic index.