VOLUNTARY ANNOUNCEMENT - NEW DRUG APPLICATION FOR ANBENITAMAB (KN026) AND DOCETAXEL FOR INJECTION (ALBUMIN-BOUND) (HB1801) FOR NEOADJUVANT TREATMENT 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 NEW DRUG APPLICATION FOR ANBENITAMAB (KN026) AND DOCETAXEL FOR INJECTION (ALBUMIN-BOUND) (HB1801) FOR NEOADJUVANT TREAT MENT 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 new drug application for Anbenitamab (KN026), co-developed by Shanghai JMT-Bio Tec hnology Co., Ltd., a subsidiary of the Company, and Jiangsu Alphamab Oncology Co., Ltd., in combin ation with the Group ’s self-developed docetaxel for injection (albumin-bound) ( ‘‘HB1801 ’’) for neoadjuvant treatment, has been accepted by the National Medical Products Administration (the ‘‘NMPA ’’) of the People ’s Republic of China and has been included in the priority review and approval proced ures. The indication for this new drug application is Anbenitamab in combination with docetaxel ( albumin-bound) ± carboplatin as neoadjuvant therapy for the treatment of HER2-positive ear ly or locally advanced breast cancer in adults. Anbenitamab Injection is a HER2 bispecific antibody that ca n simultaneously bind two non-overlapping epitopes of HER2, blocking HER2 signalling, enhancing HER2 internalisation, downregulating HER2 expression, and retaining the Fc-mediated antibody-depen dent cellular cytotoxicity (ADCC) effect. This product has been approved for marketing in China. HB1801 is one of the representative drugs independently dev eloped by the Group ’s nanomedicine technology platform. HB1801 encapsulates docetaxel in hum an albumin. It has the following advantages over docetaxel injection: (1) Safety: It causes no allergic reactions, does not require steroid premedication, and allows for high-concentration and rapi d administration, improving safety and patient compliance; (2) Efficacy: Preclinical and clinical studie s have shown that it exhibits significant antitumor activity, and it can be administered at a higher do se clinically, improving efficacy. – 1 – This marketing application is primarily based on a pivotal P hase III clinical trial (Study No.: KN026- 004/Neo-Healer) that enrolled patients with early-stage o r locally advanced HER2-positive breast cancer. The study results indicate that anbenitamab in comb ination with docetaxel for injection (albumin-bound) ± carboplatin as neoadjuvant therapy for H ER2-positive early-stage or locally advanced breast cancer, compared with the current standard of care (trastuzumab in combination with pertuzumab and docetaxel ± carboplatin), can significantl y improve the total pathological complete response rate ( ‘‘tpCR ’’), with the efficacy improvement demonstrating both statis tical significance and clinical meaningfulness, and the overall safety profile re maining manageable. In China, approximately 75% of breast cancer patients are in itially diagnosed at early-stage or locally advanced stages, and neoadjuvant therapy is the recommende d standard of care for HER2-positive early-stage or locally advanced breast cancer. Achieving t pCR through neoadjuvant therapy is an effective means of improving long-term prognosis for these patients and carries significant clinical value. KN026-004/Neo-Healer is the world ’s first Phase III study in which a HER2 bispecific antibody in combination with docetaxel for injection (albumin-boun d) has demonstrated superior efficacy over the existing neoadjuvant standard of care of anti-HER2 dual monoclonal antibodies plus chemotherapy, marking a historic breakthrough for bispecific antibody th erapy in the neoadjuvant treatment of breast cancer, and represents the first Phase III study in China in w hich an independently developed product (combination) has achieved superior efficacy results comp ared with the current neoadjuvant standard of care, which is expected to provide a new promising treatment option for Chinese patients with HER2- positive breast cancer. Currently, multiple pivotal registration clinical studie s of anbenitamab in combination with docetaxel (albumin-bound) for indications including the first-line treatment of HER2-positive breast cancer and adjuvant therapy for HER2-positive breast cancer are under way. Recently, Anbenitamab and HB1801 have been granted Breakthrough Therapy Designation by the N MPA for the first-line treatment of unresectable or metastatic HER2-positive breast cancer. By Order of the Board CSPC Pharmaceutical Group Limited CAI Dong Chen Chairman Hong Kong, 4 August 2026 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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