March 24 2026——Keymed Biosciences Inc. (the “Company”， Stock Code: 02162), together with its subsidiaries (the “Group”) announced that Ouro Medicines, its NewCo partner, has entered into a merger agreement with Gilead Sciences, Inc. (hereinafter referred to as "Gilead", NASDAQ: GILD), pursuant to which Gilead will acquire Ouro Medicines by way of a merger

The Merger Agreement provides for an upfront payment at Closing of US$1,675 million, subject to customary adjustments, and contingent milestone payment  of up to US$500 million, for a maximum total of US$2,175 million.

It is expected that based on the Company’s equity interest in Ouro Medicines, the Group will receive an initial payment of approximately US$ 250 million, and contingent milestone payment of up to approximately US$ 70 million, for a maximum total of approximately US$320 million. The final consideration receivable by the Group is subject to the achievement of relevant milestones as well as the shareholders agreement amongst the Ouro Medicines shareholders.

Meanwhile, the tiered royalty payments in respect of the licensed sales of CM336/OM336 to which Keymed is entitled will be fulfilled by Gilead. Upon the closing of the transaction, Keymed will cease to hold any equity interests in Ouro Medicines.

This merger transaction will accelerate the global development of CM336/OM336 as a potential best-in-class T Cell Engager (TCE) for the treatment of multiple autoimmune diseases with high unmet clinical needs, further unlocking and expanding the global value of CM336/OM336. At the same time, the transaction fully validates the market’s recognition of the best-in-class innovative potential of Keymed’s proprietary TCE research and development platform.

In November 2024, Keymed entered into an exclusive license agreement with Ouro Medicines, granting Ouro Medicines the exclusive global rights (excluding the Chinese mainland, Hong Kong, Macau and Taiwan) to research, develop, manufacture, register and commercialize CM336/OM336. Following the completion of the merger transaction, the license agreement will remain in full force and effect, and Keymed will continue to retain all relevant rights and interests thereunder.

CM336/OM336, the sole product of Ouro Medicines, is an innovative TCE bispecific antibody drug independently developed by Keymed, whose active ingredient is a recombinant humanised bispecific antibody targeting B-cell maturation antigen (BCMA) and CD3. CM336/OM336 is designed to enable rapid and deep B cell depletion following a limited subcutaneously administered treatment course. In ongoing Phase 1/2 clinical studies, CM336/OM336 has demonstrated transformative efficacy and a differentiated safety profile after a single treatment cycle in severe antibody-mediated diseases.

CM336/OM336 has been granted Fast Track Designation (FTD) and Orphan Drug Designation (ODD) by the U.S. Food and Drug Administration (FDA) for the treatment of autoimmune hemolytic anemia (AIHA) and immune thrombocytopenia (ITP), and is expected to enter registrational studies in 2027. The study results of CM336/OM336 for the treatment of autoimmune hemolytic anemia have been published in The New England Journal of Medicine, a world-renowned top medical journal.

Leveraging its diversified and platform-based innovation capabilities, Keymed continues to generate high-quality and high-potential innovative drugs, and conducts external collaborations through a variety of innovative models to accelerate the realization of the overseas value of its early-stage pipeline. Recently, Keymed has received a milestone payment of US$45 million from AstraZeneca in respect of the licensing project of Claudin18.2 ADC CMG901, and its NewCo partner Ouro Medicines has been acquired by Gilead Sciences. These multiple business development milestones have continuously validated the innovative potential of Keymed’s research and development platforms and the success of its diversified licensing collaborations, and further provide a sustainable impetus for the company’s subsequent independent research and development and pipeline advancement.