VOLUNTARY ANNOUNCEMENT - PHASE III CLINICAL TRIAL OF DOCETAXEL FOR INJECTION (ALBUMIN-BOUND) (HB1801) FOR THE TREATMENT OF ADVANCED BREAST CANCER OFFICIALLY INITIATED IN CHINA

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 PHASE III CLINICAL TRIAL OF DOCETAXEL FOR INJECTION (ALBUMIN-BOUND) (HB1801) FOR THE TREATMENT OF ADVANCED BREAST CANCER OFFICIALLY INITIATED IN CHINA The Board of Directors (the ‘‘Board ’’) of CSPC Pharmaceutical Group Limited (the ‘‘Company ’’, together with its subsidiaries, the ‘‘Group ’’) is pleased to announce that Phase III clinical trial of docetaxel for injection (albumin-bound) ( ‘‘HB1801 ’’) developed by the Group for the treatment of advanced breast cancer (HB1801-017) has been officially in itiated at the first centre in China recently. HB1801 is one of the representative drugs independently dev eloped by the Group ’s nanomedicine technology platform. HB1801 encapsulates docetaxel in hum an serum albumin. Compared with traditional docetaxel injection, it has significant advan tages: (1) Safety: it has no risk of allergic reactions and requires no steroid premedication; it can be a dministered rapidly at high concentration, effectively enhancing the safety profile and patient treat ment compliance; (2) Efficacy: multiple preclinical and clinical studies have demonstrated its exc ellent anti-tumour activity, allowing for higher doses in clinical practice to further improve efficacy. The HB1801-017 study is a randomised, open-label, multicen tre Phase III clinical trial, aimed at evaluating the efficacy and safety of HB1801 versus docetax el (Taxotere ®) in participants with advanced breast cancer. Currently, participant recruitme nt and screening for the HB1801-017 study are actively underway. By order of the Board CSPC Pharmaceutical Group Limited CAI Dong Chen Chairman Hong Kong, 24 September 2026 – 1 – As at the date of this announcement, the Board comprises Mr. C AI Dong Chen, Dr. CAI Lei, Mr. WEI Qingjie, Mr. ZHANG Cuilong, Mr. WANG Zhenguo, Dr. LI Chunlei , Dr. YAO Bing, Mr. CAI Xin, Mr. CHEN Weiping, Mr. QU Zhiyong and Mr. ZHANG Yiwei as Executive Directors; and Mr. WANG Bo, Mr. CHEN Chuan, Prof. WANG Hongguang, Mr. AU Chun Kwok Alan, M r. LAW Cheuk Kin Stephen and Ms. LI Quan as Independent Non-executive Directors. – 2 –

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