SinoMab BioScience Limited — Regulatory Filings 2020

Apr 7, 2020

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SinoMab BioScience Limited 中國抗體製藥有限公司

(Incorporated in Hong Kong with limited liability)

(Stock Code: 3681)

VOLUNTARY ANNOUNCEMENT – UPDATE ON SM03 REGARDING ORAL PRESENTATION AT EULAR CONGRESS 2020

The board (the “ Board ”) of directors (the “ Directors ”) of SinoMab BioScience Limited (中國 抗體製藥有限公司) (the “ Company ”) hereby wishes to announce a recent update in relation to a recognition of the Company’s flagship product, SM03, received from the European League Against Rheumatism (“ EULAR ”), a widely-recognised organisation which represents the people with arthritis/rheumatism, health professionals and scientific societies of rheumatology of all the European nations.

The Board is pleased to announce that on 30 March 2020, the Company was informed by the Scientific Programme Committee of EULAR that an abstract previously submitted by the Company has been accepted for an oral presentation (the “ Presentation ”) at the EULAR Congress 2020 (the “ Congress ”), which is currently scheduled on 3 June 2020. The Company submitted an abstract of the Phase II clinical study report of SM03 for rheumatoid arthritis (“ RA ”) titled “Efficacy and safety of SM03, a Recombinant Anti-human CD22 Monoclonal Antibody in Chinese Patients with Rheumatoid Arthritis: A Phase II randomised, double-blind, multi-dose, placebo-controlled study” (the “ Abstract ”) to EULAR on 21 January 2020, which examined the safety and clinical efficacies of SM03 in treating patients with moderate to severe RA. The Presentation, which forms part of the research and development of SM03, will be delivered by Professor Zhang Fengchun* (張奉春教授), the leading principal investigator of the Phase II clinical study of SM03 for RA. To the best of the Company’s knowledge, this is the first Phase II clinical report on the use of anti-CD22 antibodies for the treatment of RA disclosed to the scientific community, and the Directors believe that this is one of the main reasons that the Abstract has been accepted for an oral presentation at the Congress, representing an international recognition on the importance of the Company’s findings. To the best of the Company’s knowledge, the Company is one of the few Chinese biotechnology companies which have been invited for delivering oral presentations at the Congress. Further, the Abstract will be published in EULAR’s electronic “Abstract Book”, an official supplement to EULAR’s official journal “Annals of the Rheumatic Diseases (ARD)”.

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The Company’s flagship product, SM03, is a potential global first-in-target monoclonal antibody for the treatment of RA and potentially for the treatment of other immunological diseases, which is in Phase III clinical trials in China and expected to be commercialised by the end of 2021.

The Company may not be able to ultimately develop and market SM03 successfully. Shareholders of the Company and potential investors are advised to exercise caution when dealing in the shares of the Company.

By order of the Board of SinoMab BioScience Limited Dr. Shui On LEUNG Executive Director, Chairman and Chief Executive Officer

Hong Kong, 7 April 2020

As at the date of this announcement, the executive Directors are Dr. Shui On LEUNG and Mr. Jing QIANG, the non-executive Directors are Ms. Wenyi LIU, Dr. Haigang CHEN, Mr. Senlin LIU, Mr. Huiyuan MA and Mr. Xun DONG, and the independent non-executive Directors are Mr. Dylan Carlo TINKER, Mr. Michael James Connolly HOGAN, Mr. Ping Cho Terence HON and Mr. George William Hunter CAUTHERLEY.

• For identification purpose only

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