KEYMED BIO-B - VOLUNTARY ANNOUNCEMENT - UPDATE ON DISPOSAL OF EQUITY INTEREST IN OURO MEDICINES

Keymed Biosciences Inc. 康諾亞生物醫藥科技有限公司 (Incorporated in the Cayman Islands with limited liability) (Stock Code: 2162)

VOLUNTARY ANNOUNCEMENT

UPDATE ON DISPOSAL OF EQUITY INTEREST IN OURO MEDICINES

This announcement is made by the board of directors (the "Board") of Keymed Biosciences Inc. (the "Company", together with its subsidiaries, the "Group") to provide update to shareholders and potential investors of the Company on the disposal of equity interest in Ouro Medicines by iBridge HK, a wholly-owned subsidiary of the Company on a voluntary basis.

References are made to the Company's announcements dated March 24, 2026 and April

15, 2026 in relation to the disposal of the Group's minority interest in Ouro Medicines (the "Announcements"). Unless otherwise stated, all the capitalized terms used herein shall have the same meaning as those adopted in the Announcements.

The Company is pleased to announce that on June 5, 2026, the Merger Agreement of Ouro Medicines, the Group's NewCo partner, disclosed through the Announcements has now officially completed, and the Group has received an upfront payment of US$257 million.

Under the terms of the Merger Agreement, Gilead acquired all of the equity interests of Ouro Medicines for an upfront payment of US$1,675 million and a potential milestone payment of up to US$500 million. The Group has been informed that, pursuant to an arrangement between Gilead Sciences, Inc. ("Gilead") and Lakefront Biotherapeutics NV ("Lakefront", Euronext & Nasdaq: LKFT, formerly known as Galapagos), they will equally split the upfront payment (subject

to customary adjustments) and the potential milestone payment of up to US$500 million. As a shareholder of Ouro Medicines, the Group received an upfront payment of approximately US$257 million and is entitled to receive milestone payments of up to approximately US$70 million. In addition, the exclusive license agreement entered between the Group and Ouro Medicines in November 2024 will continue to be effective, and the milestone payments of up to US$610 million and tiered royalties on net sales will be fulfilled by Gilead and Lakefront.

Through this transaction, Lakefront acquired the vast majority of Ouro Medicines' team and operational assets, and will collaborate with Gilead on the subsequent development of CM336/ OM336. Lakefront will be responsible for the ongoing and future phase I/II clinical study of CM336/OM336, while Gilead will lead the registrational and late-stage studies. Gilead will retain the exclusive commercialization rights globally (excluding Greater China).

ABOUT CM336/OM336

CM336/OM336 is an innovative TCE bispecific antibody drug independently developed by the Group, and its active ingredient is a recombinant anti-B-cell maturation antigen (BCMA) and CD3 humanized bispecific antibody. CM336 can specifically bind both BCMA + target cells and CD3

• T cells to recruit immune T cells to the vicinity of the target cells, activate T cells and release cytokines, thereby inducing T-cell dependent cellular cytotoxicity (TDCC) to eliminate the target cells. Study results show that CM336/OM336 can rapidly and deeply deplete B cells and plasma cells in the peripheral blood of patients, and is expected to exert durable and effective disease control in the treatment of severe antibody-mediated autoimmune diseases, achieving an innovative paradigm shift in treatment from chronic disease management to potentially durable immune reset.

CM336/OM336 has been granted Fast Track Designation (FTD) and Orphan Drug Designation (ODD) by the Food and Drug Administration of the United States (FDA) for the treatment of two indications: autoimmune hemolytic anemia (AIHA) and primary immune thrombocytopenia (ITP),

and is expected to enter registrational studies in 2027. Previously, CM336 demonstrated excellent efficacy and differentiated advantages in clinical studies. For the indication of autoimmune hemolytic anemia (AIHA), 2 patients who had previously received multiple treatments did not experience CRS and ICANS events; one patient's hemoglobin level returned to normal on day 17, and one patient achieved complete response on day 21. Both were in treatment-free remission during the 6-month follow-up, and the study results were published in the world's top medical journal, the New England Journal of Medicine. Development plans for additional indications will be further updated by Gilead/Lakefront.

RISK WARNING

This announcement is made by the Company on a voluntary basis to provide relevant information to shareholders and potential investors of the Company. There is no assurance that the Company

will ultimately develop, launch and/or commercialize CM336 successfully. Shareholders and potential investors of the Company are advised to exercise caution when dealing in the shares of the Company.

By order of the Board Keymed Biosciences Inc. Dr. Bo CHEN Chairman

Hong Kong, June 5, 2026