Vir Biotechnology has signed its second platform collaboration of the year, licensing its masked T cell engager technology to Gilead Sciences for three programs against solid tumor targets the companies have selected but not named. Vir shares rose more than 10 percent in premarket trading after the October 14 announcement.
The economics are front loaded by platform deal standards. Gilead pays $90 million upfront, split between $65 million in cash and a $25 million equity purchase, made by buying about 1.77 million Vir shares at $14.16 each, a 30 percent premium. Vir can earn up to $45 million in near term preclinical milestones and up to $1.74 billion in later development, regulatory and commercial milestones, plus tiered royalties from high single digits to low double digits on any sales.
The technology is the point of the deal. T cell engagers force immune cells onto cancer cells, but in solid tumors their potency has come with toxicity in healthy tissue. Vir’s PRO-XTEN approach keeps each engager masked and inactive until proteases found in the tumor microenvironment cut the mask away, aiming to concentrate activity inside the tumor and extend the molecule’s half life. Vir will run discovery and optimization using its dAIsY AI assisted engineering platform. Gilead holds exclusive rights to develop, manufacture and commercialize whatever Vir nominates.
Gilead follows Astellas, which signed a PRO-XTEN collaboration with Vir in February 2026 around a prostate cancer engager. For Gilead, whose oncology portfolio leans on cell therapy and antibody drug conjugates, the deal buys an option on a class it does not build itself. For Vir, partner upfronts are becoming its financing model: outside validation and non dilutive cash now, with the valuation case still resting on whether masking actually widens the therapeutic window in patients.