VOLUNTARY ANNOUNCEMENT - MARKETING AUTHORISATION APPLICATION FOR PERTUZUMAB INJECTION ACCEPTED BY THE NMPA

Hong Kong Exchanges and Clearing Limited and The Stock Excha nge 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 whatsoe ver for any loss howsoever arising from or in reliance upon the whole or any part of the contents of this ann ouncement. CSPC PHARMACEUTICAL GROUP LIMITED (Incorporated in Hong Kong with limited liability) (Stock Code: 1093) ʮ ̡ VOLUNTARY ANNOUNCEMENT MARKETING AUTHORISATION APPLICATION FOR PERTUZUMAB INJECTION ACCEPTED BY THE NMPA The Board of Directors (the ‘‘Board ’’) of CSPC Pharmaceutical Group Limited (the ‘‘Company ’’, together with its subsidiaries, the ‘‘Group ’’) is pleased to announce that the marketing authorisation application for Pertuzumab Injection (the ‘‘Product ’’) developed by CSPC Megalith Biopharmaceutical Co., Ltd. ( 石藥集團巨石生物製藥有限公司), a subsidiary of the Company, has been accepted by the National Medical Products Administration (the ‘‘NMPA ’’) of the People ’s Republic of China. The Product has been applied for as a Class 3.3 therapeutic biolo gical product. It is indicated for the treatment of HER2-positive breast cancer. The Product is a recombinant humanised anti-HER2 monoclona l antibody injection administered once every three weeks. It specifically binds to the extracellul ar dimerisation domain (Subdomain II) of the HER2 receptor and blocks ligand-dependent dimerisation of HER2 with itself or other HER family members, thereby arresting the cell cycle and inducing apop tosis. In addition, the Product is capable of mediating antibody-dependent cell-mediated cytotoxicit y. This application is primarily supported by a Phase III equiv alence clinical trial enrolling patients with early-stage or locally advanced HER2-positive breast canc er. Results of clinical trials demonstrated that the Product, when used as neoadjuvant treatment for early-s tage or locally advanced HER2-positive breast cancer, is equivalent to the reference drug in terms o f efficacy. The Product also exhibited a favourable safety and tolerability profile comparable to t hose of the reference drug. – 1 – The Product was developed in accordance with relevant resea rch guidelines of biosimilars. Through a stepwise program encompassing pharmaceutical studies, no n-clinical studies, human pharmacokinetics and clinical efficacy and safety, the Product has been scien tifically, rigorously and comprehensively demonstrated to be highly similar to the reference drug in te rms of quality, safety and efficacy, with no clinically meaningful differences. For and on behalf of the Board CSPC Pharmaceutical Group Limited CAI Dong Chen Chairman Hong Kong, 12 November 2025 As at the date of this announcement, the Board comprises Mr. C AI Dong Chen, Mr. ZHANG Cuilong, Mr. WANG Zhenguo, Mr. WANG Huaiyu, Dr. LI Chunlei, Dr. YAO Bin g, Mr. CAI Xin and Mr. CHEN Weiping as Executive Directors; and Mr. WANG Bo, Mr. CHEN Chu an, Prof. WANG Hongguang, Mr. AU Chun Kwok Alan, Mr. LAW Cheuk Kin Stephen and Ms. LI Quan as Independent Non-executive Directors. – 2 –

The release as fetched from its publisher. irasia.com ↗