SinoMab BioScience Limited — Board/Management Information 2025

Oct 8, 2025

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.

SINOMAB

SinoMab BioScience Limited

中國抗體製藥有限公司

(Incorporated in Hong Kong with limited liability)

(Stock code: 3681)

CHANGE OF COMPANY SECRETARY

The board of directors (the "Board") of SinoMab BioScience Limited (the "Company") hereby announces that Ms. CHOW Yuk Yin Ivy ("Ms. Chow") has tendered her resignation as the company secretary of the Company with effect from 8 October 2025. Ms. Chow confirmed that she has no disagreement with the Board and there is no matter relating to her resignation that needs to be brought to the attention of The Stock Exchange of Hong Kong Limited or the shareholders of the Company.

The Board further announces that Ms. LAI Florence Wai Ki ("Ms. Lai") has been appointed to replace Ms. Chow as the company secretary of the Company with effect from 8 October 2025. Ms. Lai is the corporate services partner of PwC Corporate Services Limited. Ms. Lai has over 15 years of professional experience in providing corporate compliance and advisory services to Hong Kong listed companies as well as multinationals, private and offshore entities. Ms. Lai is a member of the Hong Kong Institute of Certified Public Accountants. She holds a bachelor's degree in Accounting and Finance from the University of Warwick in the United Kingdom.

The Board would like to take this opportunity to express its sincere gratitude to Ms. Chow for her contribution to the Company during her tenure of service and also extend a warm welcome to Ms. Lai on her new appointment.

By Order of the Board

SinoMab BioScience Limited

Dr. Shui On LEUNG

Executive Director, Chairman and Chief Executive Officer

Hong Kong, 8 October 2025

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. Xiaosu WANG and Dr. Jianmin ZHANG, and the independent non-executive directors of the Company are Mr. George William Hunter CAUTHERLEY, Mr. Ping Cho Terence HON, Dr. Chi Ming LEE, Ms. Chi Sau Giselle LEE and Mr. Nan SHEN.