Raising the bar for prostate cancer treatment: Moving together to create impact

In cancer drug development, the weight of scientific decisions and their real-world consequences for people drives a deep sense of urgency in everything we do.

At Vir Bio, we are building our oncology portfolio with a clear ambition: to bring differentiated immunotherapies to patients who need better options and to do so with both speed and discipline.

Our recent collaboration with Astellas to co-develop and co-commercialize VIR-5500 in prostate cancer reflects this ambition and marks an important step forward for our oncology strategy.

VIR-5500 represents a promising class of drugs called T-cell engagers (TCEs), which have proven highly effective in blood cancers and could be powerful tools to treat difficult solid tumors. We recently presented early data showing that VIR-5500 could be a best-in-class therapy and have a transformative effect in people living with metastatic prostate cancer. To understand why this matters so much, it’s important to start with the reality patients face today.

A large and persistent unmet need in prostate cancer

Prostate cancer is a significant global health burden impacting roughly one in eight men. Those who eventually progress to metastatic castration-resistant prostate cancer (mCRPC) face sobering odds. The five-year survival rate is only around 30%, and there are an estimated 100,000 people with mCRPC across the United States and Europe alone. Unmistakably, there is a growing need for new therapies that can deliver long-term disease control without compromising quality of life.

VIR-5500 combines the strength of a TCE with PRO-XTEN^® masking technology, which is designed to function like an invisibility cloak, allowing the drug to circulate through the body undetected and inactive until it reaches the tumor. Only in the tumor microenvironment does the cloak get removed, enabling precise engagement of T-cells with cancer cells. By conditionally activating the immune response in the tumor microenvironment, we aim to preserve anti-tumor activity while improving tolerability, addressing one of the longstanding challenges of TCEs in solid tumors. Striking that balance between efficacy and safety is critical if these therapies are to fulfill their promise for patients.

Progress that reaches beyond the clinic

As we prepared to present new data from the VIR-5500 Phase 1 trial at ASCO GU, we reviewed profound imaging that showed the effects of VIR-5500 on reducing the cancerous tumors and lesions burdening patients in the trial. Metastatic disease is often resistant to therapy and associated with poor prognosis. With each image, I was struck by what these tumor reductions could mean for patients’ quality of life.

The images offer a clear reminder of what scientific progress can mean, especially for people who are severely ill and have exhausted multiple lines of therapy.

These early insights reinforce why we are committed to advancing this program with rigor, care and urgency for people living with prostate cancer.

Astellas: Experience where it matters most

As VIR-5500 progressed in the clinic, it became clear to us that accelerating development would be critical to maximizing impact in the competitive and fast-moving prostate cancer landscape. Achieving that acceleration requires experience, resources and global reach. With that in mind, we sought out a collaborator that shared our sense of urgency and ambition for the asset and with a mission rooted in patient impact.

Astellas is the global leader in prostate cancer with decades of deep clinical, regulatory and commercial expertise resulting in a strong ability to bring important medicines to patients at scale. Further, as demonstrated through their track record of co-developing blockbuster therapies with biotech partners, they understand how to translate innovation into global impact while working collaboratively. This was essential for us. It’s important for our team to remain deeply involved in VIR-5500’s development and retain meaningful long-term value.

A partnership built for speed, scale and shared value

By combining Vir Bio’s innovation in TCEs with Astellas’ deep experience in global development and lifecycle execution, we believe we can accelerate VIR-5500 through the clinic and make faster, better-informed decisions at every stage.

This collaboration allows both teams to bring their strengths to the table and stay tightly focused on what matters most: delivering meaningful new options to patients as quickly as possible.

We are excited to work alongside Astellas, the world’s leader in prostate cancer, and even more excited about what this partnership could mean for people living with this disease.

Vir Biotechnology has exclusive rights to the PRO-XTEN^® masking platform for oncology and infectious disease. PRO-XTEN^® is a trademark of Amunix Pharmaceuticals, Inc., a Sanofi company.

Closing of the Astellas global collaboration is contingent on customary closing conditions, including clearance under the Hart-Scott-Rodino (HSR) Act.