Gilead Sciences Expands Autoimmune Franchise Through USD 2.175 Billion Acquisition of Ouro Medicines

Gilead Sciences announced a definitive agreement to acquire Ouro Medicines, a privately held clinical-stage biotechnology company, for USD 1.675 billion in upfront cash plus up to USD 500 million in contingent milestone payments. The Gilead Ouro Medicines acquisition positions Gilead to enter the rapidly consolidating immune reset therapeutics space, adding a differentiated BCMAxCD3 bispecific antibody to its inflammation portfolio alongside its existing CAR-T assets through Kite.

Under the terms, Gilead acquires all outstanding equity of Ouro Medicines for a combined potential value of USD 2.175 billion. The USD 1.675 billion upfront payment is payable at closing in cash, with the remaining USD 500 million tied to undisclosed future milestones. Gilead is simultaneously in advanced discussions with Galapagos regarding a strategic collaboration on the acquired assets. The contemplated Galapagos Gilead collaboration would see Galapagos absorb 50 percent of both the upfront consideration and milestone payments, approximately USD 837.5 million and up to USD 250 million respectively. Galapagos would take on substantially all of Ouro's operating assets and employees, bear development costs through initiation of registrational studies, and share registrational costs equally with Gilead. Gilead retains sole worldwide commercialization rights outside Greater China, where Keymed Biosciences holds existing rights, and would pay Galapagos royalties of 20 to 23 percent of net sales. The transaction is subject to regulatory clearance and customary closing conditions.

The Ouro Medicines T Cell Engager Platform and OM336

The centerpiece of the deal is OM336, known as gamgertamig, a clinical-stage BCMAxCD3 bispecific T cell engager designed to achieve rapid and deep B cell and plasma cell depletion following a limited subcutaneously administered treatment course. The molecule redirects a patient's endogenous T cells toward BCMA-expressing plasma cells, eliminating the pathogenic B cell populations that drive antibody-mediated autoimmune disease. This mechanism bypasses the need for ex vivo cell manufacturing required by CAR-T approaches, offering a potentially more scalable and accessible path to immune reset.

In ongoing Phase 1/2 clinical studies, OM336 has demonstrated efficacy and a differentiated safety profile after a single treatment cycle in severe orphan autoimmune conditions including autoimmune hemolytic anemia and immune thrombocytopenia. The U.S. FDA has granted both Fast Track and Orphan Drug Designation for these indications, and the molecule is expected to enter registrational studies in 2027. OM336 was originally in-licensed from Keymed Biosciences and has been the subject of case reports published in The New England Journal of Medicine. Ouro Medicines, launched in January 2025 with USD 120 million in funding from Monograph Capital in partnership with GSK, with additional backing from TPG, NEA, and Norwest, has since expanded clinical development into Sjögren's disease and idiopathic inflammatory myopathy.

The distinction between BCMA-directed and CD19-directed B cell depletion is relevant. While CD19-targeted approaches deplete B cells broadly, BCMA-targeted agents such as OM336 also deplete long-lived plasma cells, which are the primary producers of pathogenic autoantibodies and are often resistant to conventional anti-CD20 therapies. This deeper depletion may enable more durable remissions in antibody-driven diseases.

Gilead Sciences Autoimmune Diseases Strategy and the Competitive Landscape

The Gilead Ouro Medicines acquisition occurs within a period of sustained deal-making activity in bispecific antibodies and cell engagers targeting B cells for autoimmune diseases. Several transactions from 2024 and 2025 establish the valuation context. In 2024, Merck acquired global rights to CN201, a CD3×CD19 bispecific antibody from Curon Biopharmaceutical, for USD 700 million upfront and up to USD 1.3 billion total. In March 2025, UCB licensed ATG-201, a CD19/CD3 bispecific T cell engager from Antengene, in a deal valued at up to USD 1.18 billion. That same month, Sanofi acquired DR-0201, a CD20-directed bispecific myeloid cell engager from Dren Bio, for USD 600 million upfront and up to USD 1.9 billion, subsequently returning for a platform collaboration valued at up to an additional USD 1.7 billion. In June 2025, AbbVie acquired Capstan Therapeutics, an in vivo CAR-T company targeting CD19 and BCMA for autoimmune diseases, for USD 2.1 billion in cash. Cullinan Therapeutics licensed velinotamig, a BCMA/CD3 bispecific from Genor Biopharma, in a deal valued at up to USD 712 million.

The Gilead inflammation portfolio now spans CAR-T cell therapies through Kite and, with this acquisition, bispecific T cell engagers. The two modalities address overlapping patient populations through distinct mechanisms. CAR-T therapies require leukapheresis, ex vivo manufacturing, and lymphodepletion, limiting their scalability to specialized centers. Subcutaneously administered T cell engagers such as OM336 could extend immune reset approaches to broader patient populations and community settings. Gilead's recent acquisition of Arcellx for approximately USD 7.8 billion in February 2026, securing the next-generation CAR-T asset anito-cel for multiple myeloma, and the LEO Pharma STAT6 inhibitor partnership further illustrate the company's strategy of assembling complementary modalities across inflammation and oncology.

The convergence of multiple large pharmaceutical companies on B cell depletion for autoimmune disease reflects several factors. Safety margins in autoimmunity are generally more favorable than in oncology, where cytokine release syndrome and neurotoxicity have constrained T cell engager development. The orphan disease designations secured by OM336 provide accelerated regulatory pathways and market exclusivity. Manufacturing scalability of bispecific antibodies relative to autologous cell therapies reduces cost-of-goods and supply chain complexity. The clinical evidence accumulating across multiple programs suggests that immune reset, defined as durable drug-free remission following a limited treatment course, may represent a paradigm shift away from chronic immunosuppression in antibody-mediated autoimmune diseases.

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