Vir Biotechnology’s VIR-5500 Delivers 82% PSA50, 53% PSA90 and Secures Astellas Collaboration
Vir Biotechnology’s Phase 1 trial of VIR-5500 in metastatic prostate cancer showed dose-dependent anti-tumor activity, with 82% PSA50 declines, 53% PSA90 declines and objective responses in 45% of RECIST-evaluable patients at higher dose cohorts. It signed a collaboration with Astellas and plans a registrational trial in 2027.
1. Positive Phase 1 Trial Results
Vir Biotechnology enrolled metastatic prostate cancer patients in a dose-escalation Phase 1 study of PSMA-targeting T-cell engager VIR-5500, achieving an 82% PSA50 rate, a 53% PSA90 rate and objective RECIST responses in 45% of evaluable patients at higher dose cohorts, underscoring a strong antitumor signal.
2. PRO-XTEN Masking Strategy and Safety Profile
VIR-5500 utilizes the PRO-XTEN® platform to mask the T-cell engager until it reaches tumor sites, resulting in a favorable safety and tolerability profile across cohorts and supporting its potential to minimize off-target toxicity while maintaining therapeutic potency.
3. Astellas Collaboration and Future Development
Vir entered a global collaboration with Astellas to develop and commercialize VIR-5500, securing financial and operational support; the company intends to initiate a registrational Phase 3 trial in 2027 based on these encouraging early results.