Vir Biotechnology has moved its prostate cancer program deeper into clinical testing. 

 

The biotech innovator has announced that the first patient has been dosed in expansion cohorts of its Phase 1 study of VIR-5500, a PSMA-targeted, PRO-XTEN dual-masked T-cell engager for metastatic prostate cancer.

 

The trial is evaluating VIR-5500 both as a monotherapy in late-line metastatic castration-resistant prostate cancer (mCRPC) and in combination with an androgen receptor pathway inhibitor (ARPI) in earlier-line mCRPC and metastatic hormone-sensitive prostate cancer (mHSPC).

 

“The initiation of the VIR-5500 expansion cohorts underscores the significant momentum behind this program and the enthusiasm we are seeing across the clinical community,” said Marianne De Backer, Chief Executive Officer, Vir Biotechnology. 

 

“We are encouraged by the promising anti-tumor activity shown in the Phase 1 data announced earlier this year and look forward to collaborating with Astellas after closing of the transaction to explore VIR-5500’s potential to make a meaningful difference across the spectrum of metastatic prostate cancer.”

 

The newly opened monotherapy expansion in late-line mCRPC follows earlier dose-escalation data showing a favorable safety profile and encouraging anti-tumor activity.

 

“Building on the encouraging Phase 1 dose-escalation monotherapy data, this milestone represents an important step in further evaluating VIR-5500’s best-in-class potential,” said Anthony Jarkowski, Primary Focus Lead, Immuno-oncology at Astellas Pharma. 

 

“We look forward to starting our collaboration with Vir Biotechnology to potentially benefit more people living with prostate cancer, where there remains a significant unmet medical need.”

 

Meanwhile, combination dosing of VIR-5500 with enzalutamide continues in early-line mCRPC patients. The companies expect to begin dosing expansion cohorts in both early-line mCRPC and mHSPC in the coming months, with a path toward pivotal Phase 3 trials anticipated in 2027.