VOLUNTARY ANNOUNCEMENT - PHASE II CLINICAL TRIAL OF SYH2062 INJECTION FOR THE TREATMENT OF ADULT ESSENTIAL HYPERTENSION 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 SYH2062 INJECTION FOR THE TREATMENT OF ADULT ESSENTIAL HYPERTENSION 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 (SYH2062 –003) of SYH2062 Injection (the ‘‘Product ’’) developed by the Group for the treatment of adult essential hypertension, has been officially initiat ed at the first centre in China. The Product is a chemically modified, double-stranded smal l interfering RNA (siRNA) consisting of 21 to 23 nucleotides in length, utilising N-acetylgalactosam ine (GalNAc) conjugation technology to achieve liver-targeted delivery. The Product can specific ally silence the angiotensinogen (AGT) gene, inhibit the expression of the corresponding protein, and al leviate the over-activation of the renin- angiotensin-aldosterone system (RAAS), thereby exerting effective pathway inhibition and delivering long-term stable blood pressure control. Previously, the Product obtained the Notice of Approval for Clinical Trial of Drug from the National Medical Products Administration of the People ’s Republic of China in December 2024. Currently, the Group has obtained Phase I clinical trial data in hypertensi ve patients, which have preliminarily validated its safety profile as well as pharmacokinetic and pharmacodynamic characteristics in humans. The Product is expected to bring longer-lasting and more sta ble blood pressure-lowering benefits to adult patients with essential hypertension in China. – 1 – This Phase II clinical trial is a multi-centre, randomised, double-blind, placebo-controlled clinical trial designed to evaluate the efficacy and safety of the Product i n subjects with mild-to-moderate essential hypertension. Currently, the recruitment and screening of trial subjects are actively underway. By order of the Board CSPC Pharmaceutical Group Limited CAI Dong Chen Chairman Hong Kong, 29 July 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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