On April 16, 2026 Vir Biotechnology, Inc. (Nasdaq: VIR) reported that its global collaboration and licensing agreement with Astellas announced on February 23, 2026 has closed following expiration of the waiting period under the Hart-Scott-Rodino Antitrust Improvements Act of 1976. The collaboration aims to accelerate the development of VIR-5500, a prostate-specific membrane antigen (PSMA)-targeted, PRO-XTEN dual-masked T-cell engager (TCE) for metastatic prostate cancer.
Schedule your 30 min Free 1stOncology Demo!
Discover why more than 1,500 members use 1stOncology™ to excel in:
Early/Late Stage Pipeline Development - Target Scouting - Clinical Biomarkers - Indication Selection & Expansion - BD&L Contacts - Conference Reports - Combinatorial Drug Settings - Companion Diagnostics - Drug Repositioning - First-in-class Analysis - Competitive Analysis - Deals & Licensing
Schedule Your 30 min Free Demo!
Summary Financial Terms
Upon closing, Vir Biotechnology receives a $240 million upfront payment and a $75 million equity investment at a price of $10.36 per share. The Company will also receive a near-term $20 million milestone payment, will split U.S. profit/loss equally with Astellas (50/50), and is eligible to receive up to an additional $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.
About VIR-5500
T-cell engagers (TCEs) are powerful anti-tumor agents that can direct the immune system, specifically T-cells, to destroy cancer cells. VIR-5500 is an investigational PRO-XTEN dual-masked TCE currently being evaluated in an open-label, non-randomized Phase 1 clinical trial (NCT05997615) designed to assess the safety, pharmacokinetics and preliminary efficacy in participants with metastatic castration-resistant prostate cancer (mCRPC). VIR-5500 is the only dual-masked PSMA-targeting TCE in clinical evaluation.
VIR-5500 combines a bispecific PSMA and CD3 binding TCE with the PRO-XTEN masking technology. The PRO-XTEN masking technology is designed to keep the TCEs inactive (or masked) until they reach the tumor microenvironment, where tumor-specific proteases cleave off the mask and activate the TCEs, leading to killing of cancer cells by T-cells. By confining the activity to the tumor microenvironment, we aim to circumvent the traditionally high toxicity associated with unmasked TCEs and increase their efficacy and tolerability. Additionally, the mask is designed to help drug candidates stay in the bloodstream longer in their inactive form, allowing them to better reach the site of action and potentially allowing for less frequent dosing regimens.
(Press release, Vir Biotechnology, APR 16, 2026, View Source [SID1234664447])