VOLUNTARY ANNOUNCEMENT - PHASE II CLINICAL TRIAL OF SIROLIMUS FOR INJECTION (ALBUMIN-BOUND) FOR THE TREATMENT OF EPITHELIOID HAEMANGIOENDOTHELIOMA OFFICIALLY INITIATED AT THE FIRST CENTRE 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 II CLINICAL TRIAL OF SIROLIMUS FOR INJECTION (ALBUMIN-BOUND) FOR THE TREATMENT OF EPITHELIOID HAEMANGIOENDOTHELIOMA OFFICIALLY INITIATED AT THE FIRST CENTRE 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 the Phase II clinical trial of Sirolimus for Injection (Albumin-Bound) (the ‘‘Product ’’), independently developed by the Group, for the treatment of patients with progressive/symptomatic ep ithelioid haemangioendothelioma has been officially initiated at the first centre in China. The Product is a macrolide immunosuppressant and a highly se lective inhibitor of the mammalian target of rapamycin ( ‘‘mTOR ’’). Sirolimus binds to the immunophilin FKBP12 to form an immunosuppressive complex that blocks the activation of th e mTOR pathway. On one hand, it inhibits cytokine-mediated T-lymphocyte activation and prolifera tion and arrests the cell cycle progression from the G1 phase to the S phase; on the other hand, it also downregu lates the body ’s antibody production, thereby exerting potent immunosuppressive effects. The Pr oduct is a Class 2.2 chemical drug, being a modified new drug. The clinical trial is a multi-centre, open-label, non-rand omised Phase II clinical trial. It intends to enrol patients with histologically confirmed progressive or sym ptomatic epithelioid haemangioendothelioma who are unsuitable for radical surgery and are determined by the investigators to require systemic therapy, aiming to evaluate the efficacy and safety of the Pr oduct in patients with progressive or symptomatic epithelioid haemangioendothelioma. Current ly, the recruitment and screening of participants are actively underway. By Order of the Board CSPC Pharmaceutical Group Limited CAI Dong Chen Chairman Hong Kong, 16 July 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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