On October 14, 2026, Vir Biotechnology, Inc. (Nasdaq: VIR) announced a collaboration and license agreement with Gilead to discover and engineer three novel PRO-XTEN® dual-masked T-cell engager (TCE) development candidates targeting selected solid tumor-associated antigens. Gilead will have an exclusive license to develop and commercialize the novel TCEs.
The collaboration combines Vir Biotechnology's T-cell engager discovery, AI-enabled protein engineering and clinically-validated PRO-XTEN® masking technology with Gilead's oncology development and commercialization expertise. This is the Company's second collaboration building on the universal PRO-XTEN® masking technology.
Through this collaboration, Vir Biotechnology will apply its deep expertise in TCE discovery and protein engineering, its proprietary dAIsY™ (data AI structure and antibodY) platform for rapid, multiparameter optimization of high-quality TCEs and the universal PRO-XTEN® masking technology to develop next-generation TCEs, each with potent anti-tumor activity and a wide therapeutic index across solid tumor targets addressing areas of high unmet need.
“We believe TCEs have a powerful role to play in the future of immunotherapy to treat cancer. This collaboration with Gilead provides an opportunity to generate multiple differentiated candidates aimed at difficult-to-address solid tumors and to expand the potential impact of our science, while also advancing our own clinical oncology portfolio,” said Marianne De Backer, President and Chief Executive Officer of Vir Biotechnology. “This transaction provides further external validation of Vir Biotechnology's integrated discovery capabilities and the broad potential of the PRO-XTEN® platform.”
“We look forward to combining Gilead's established and growing oncology capabilities, including our extensive development expertise and focus on next-generation immunotherapies, with Vir Biotechnology's innovative discovery capabilities,” stated Flavius Martin, MD, Executive Vice President, Research, Gilead Sciences. “Together with Vir Biotechnology, we seek to bring meaningful innovative therapeutics to patients.”
Under the terms of the agreement, Vir Biotechnology will be responsible for discovery, design and optimization of three novel PRO-XTEN® dual-masked TCE development candidates targeting selected solid tumor-associated antigens. Gilead will have an exclusive license to nominate and advance candidates generated under the collaboration and will be responsible for subsequent development, manufacturing and commercialization activities. Vir Biotechnology will be eligible to receive up to $135 million in total upfront and near-term preclinical milestone payments, consisting of $90 million in upfront consideration, which includes $65 million in cash and a $25 million equity investment at a 30% premium, and up to $45 million in potential near-term preclinical milestones. In addition, Vir Biotechnology has the potential to receive up to $1.74 billion in further development, regulatory and commercial milestones, along with tiered high single-digit to low double-digit royalties on net sales.
T-cell engagers (TCEs) are powerful anti-tumor agents designed to direct the immune system, specifically T-cells, to destroy cancer cells. TCEs have become an important treatment option for blood cancers, but their usage in solid tumors has been limited due to toxicity. The universal PRO-XTEN® masking technology is designed to extend the half-life of the molecule and to keep 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 extending the half-life and confining activity to the tumor microenvironment, the PRO-XTEN® technology could limit toxicity, widen the therapeutic index of TCEs, and potentially enable less frequent dosing regimens.
Following the announcement, Vir Biotechnology's stock rose more than 10% in pre-market trading.

Source: https://investors.vir.bio/news/news-details/2026/Vir-Biotechnology-Enters-Multi-Program-Collaboration-and-License-Agreement-with-Gilead-Sciences-to-Discover-and-Develop-Novel-PRO-XTEN-Dual-masked-T-cell-Engagers-for-Solid-Tumors/default.aspx