Astellas Pharma Inc. and Vir Biotechnology Inc. have entered into a global strategic collaboration to advance VIR-5500, an investigational PRO-XTEN dual-masked CD3 T-cell engager (TCE) targeting PSMA for the treatment of prostate cancer. The collaboration aims to accelerate the development of VIR-5500 and further strengthen Astellas’ oncology pipeline and prostate cancer leadership.

Treating Prostate Cancer

Despite recent advances in treatment, prostate cancer, especially metastatic castration-resistant prostate cancer (mCRPC), remains an aggressive and difficult cancer to treat. Patients who progress to mCRPC develop therapeutic resistance and currently have limited treatment options.

VIR-5500 is a potential best-in-class dual-masked Prostate-Specific Membrane Antigen (PSMA)-targeting TCE and is currently in Phase 1 development for people with advanced, metastatic prostate cancer (NCT05997615). VIR-5500 combines a bispecific PSMA and CD3 binding TCE with the PRO-XTEN masking technology, which is designed to keep the TCEs masked (or inactive) until they reach the tumor microenvironment, reducing off-target effects and improving the therapeutic index.

Adam Pearson, Chief Strategy Officer, Astellas, said, “This strategic collaboration allows Astellas and Vir Biotechnology to combine our expertise and reaffirms our commitment to improving the lives of people with prostate cancer.”

Marianne De Backer, M.Sc., Ph.D., MBA, Chief Executive Officer, Vir Biotechnology, added, “Astellas is an ideal collaborator for the VIR-5500 program given the company’s successful track record advancing therapies across the treatment continuum, building blockbuster franchises and delivering value to patients through strategic development alliances with other biotech partners. This collaboration will enable more rapid advancement of VIR-5500 to potentially benefit more people living with prostate cancer.”

Terms of the Agreement

Under the terms of the agreement, Vir Biotechnology will receive $335 million in upfront and near-term payments, including $240 million in cash, $75 million in equity investment at a 50% premium, and a near-term $20 million milestone. Global development costs for VIR-5500 will be shared, with Astellas responsible for 60% and Vir Biotechnology responsible for 40% of all costs. Vir Biotechnology will continue the ongoing Phase 1 trial, until responsibility is transitioned to Astellas, after which Astellas will be responsible for all development activities.

In the U.S., Vir Biotechnology will have the option to co-promote VIR-5500 with Astellas, and profit/loss will be shared equally. Outside the U.S., Astellas will be exclusively responsible for commercialization of VIR-5500.

In addition, Vir Biotechnology is eligible to receive up to $1.37 billion in development, regulatory and sales milestones, along with tiered, double-digit royalties on ex-U.S. net sales. Under the terms of Vir Biotechnology’s licensing agreement with Sanofi, a portion of certain collaboration proceeds will be shared with Sanofi.