SinoMab BioScience Limited — Regulatory Filings 2022

Jun 15, 2022

Hong Kong Exchanges and Clearing Limited and The Stock Exchange of Hong Kong Limited take no responsibility for the contents of this announcement, make no representation as to its accuracy or completeness and expressly disclaim any liability whatsoever for any loss howsoever arising from or in reliance upon the whole or any part of the contents of this announcement.

==> picture [29 x 44] intentionally omitted <==

==> picture [29 x 44] intentionally omitted <==

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 FIRST HEALTHY SUBJECT DOSED IN A PHASE I CLINICAL TRIAL OF SM17 IN THE U.S.

Reference is made to the announcements of SinoMab BioScience Limited (中國 抗 體製 藥 有 限 公司 ) (the ‘‘Company’’, together with its subsidiaries, the ‘‘Group’’) dated 16 February 2022 and 14 March 2022 in relation to the latest research and development progress of one of the Group’s key products, SM17.

The board of directors (the ‘‘Board’’) of the Company is pleased to announce that the first healthy subject has been successfully dosed in a Phase I FIH (First-in-Human) clinical trial of SM17 in the U.S. on 14 June 2022 (EST local time). The phase I study is a Single Ascending Dose (SAD) and Multiple Ascending Doses (MAD) to investigate the safety, tolerability, and pharmacokinetics of SM17 in healthy subjects.

SM17 is a humanized, IgG4-k monoclonal antibody targeting IL-17RB. SM17 could suppress Th2 immune responses by binding to IL-17RB on Type 2 Innate Lymphoid cells (ILC2s), blocking a cascade of responses induced by interleukin-25 (IL-25). IL-25 is a critical cytokine classified as ‘‘alarmin’’, which has shown to be implicated in the pathogenesis of airway viral responses and allergic disease, such as asthma. Patients with severe, uncontrolled asthma are at a risk of recurrent asthma exacerbations and hospitalizations, and uncontrolled severe asthma is associated with increased mortality/ morbidity, diminished quality of life and increased health expenditures. Current approved therapies for severe asthma, including biologics, can reduce asthma annual exacerbations to a certain extent. However, there is still an unmet medical need for additional effective therapies, particularly for patients who do not respond to current treatments. We expected that targeting upstream mediators of the Th2 inflammatory cascade, such as IL-17RB, will have a broad effect on airway inflammation. We believe the huge potential of SM17 to satisfy unmet medical needs in asthma treatment.

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

Hong Kong, 15 June 2022

– 1 –

As at the date of this announcement, the executive director of the Company is Dr. Shui On LEUNG, the non-executive directors of the Company are Dr. Haigang CHEN, Mr. Xun DONG, Ms. Wenyi LIU, Ms. Jie LIU and Mr. Lei SHI, and the independent non-executive directors of the Company are Mr. George William Hunter CAUTHERLEY, Mr. Ping Cho Terence HON, Dr. Chi Ming LEE and Mr. Dylan Carlo TINKER.

– 2 –