Gamgertamig, a BCMAxCD3 bispecific T cell engager developed by Ouro Medicines, sits at the center of a three-way collaboration agreement announced March 31 that links Galapagos NV (Euronext & NASDAQ: GLPG), Gilead Sciences (NASDAQ: GILD), and the privately held San Francisco-based biotech. The Galapagos Gilead collaboration is structured around Gilead's concurrent definitive agreement to acquire Ouro for USD 1.675 billion upfront plus up to USD 500 million in contingent milestones, with Galapagos bearing 50% of both figures. Galapagos simultaneously acquires Ouro's operational assets — facilities and personnel — and receives development and commercialization licenses to gamgertamig and additional preclinical programs. Galapagos was first reported to be in discussions to participate in the deal earlier when Gilead unveiled its plans to acquire Ouro earlier this month.
Under the Framework Agreement, Galapagos will fund all pre-registrational development costs for gamgertamig, while registration-enabling studies will be split equally between Galapagos and Gilead, with execution leadership divided by indication. Upon commercialization, Gilead will pay Galapagos tiered royalties of 20%-23% on net sales outside KeyMed Biosciences' Greater China territory. Galapagos is also eligible for up to USD 100 million in milestone payments upon Gilead's initiation of first registrational trials in indications beyond the lead programs.
The deal also grants Galapagos a preclinical portfolio of three additional autoimmune-focused programs from Ouro, on which Gilead holds options to enter a 50/50 profit split post clinical proof-of-concept at USD 75 million per program. A separate provision — the OLCA Waiver — releases USD 500 million of Galapagos cash from obligations under the companies' existing 2019 Option, License and Collaboration Agreement, including up to USD 150 million available for share repurchases or capital distributions.
Gamgertamig (OM336) is described as a BCMAxCD3 bispecific T cell engager designed to redirect a patient's own T cells toward BCMA-expressing plasma cells, enabling rapid and deep B-cell depletion following a short, subcutaneously administered treatment course. The molecule originated at KeyMed Biosciences (HKEX: 2162.HK), which retains Greater China rights under a head license with Ouro; Galapagos will fund 50% of royalties and 25% of milestones owed to KeyMed under that agreement. In ongoing Phase I/II studies, gamgertamig has been evaluated in autoimmune hemolytic anemia and immune thrombocytopenia — antibody-mediated orphan diseases where pathogenic plasma cells drive disease — and the US FDA has granted the molecule both Fast Track and Orphan Drug Designation for both conditions. Registrational studies are expected to begin as early as 2027.