VOLUNTARY ANNOUNCEMENT - NMPA ACCEPTS MARKETING AUTHORISATION APPLICATION FOR SECUKINUMAB INJECTION

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 NMPA ACCEPTS MARKETING AUTHORISATION APPLICATION FOR SECUKINUMAB INJECTION 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 Secukinumab 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 submitted for registration as a C lass 3.3 therapeutic biological product. The Product is a fully human IgG1 monoclonal antibody that se lectively binds to fully human interleukin (IL)-17A ( ‘‘IL-17A ’’), blocking its interaction with the IL-17A receptor. IL-17 A is a key cytokine in the inflammatory response and disease progress ion of diseases such as psoriasis, psoriatic arthritis and axial spondyloarthritis, playing a central r ole in their pathogenesis. As an IL-17A inhibitor, the Product can specifically neutralise IL-17A and inhibit its pro-inflammatory effects, thereby effectively alleviating disease symptoms, provid ing sustained improvement in disease activity, and delivering long-term clinical benefits to patients. Th e fully human structure of the Product results in a lower incidence of anti-drug antibodies, combining dur able efficacy with a favourable safety profile. The Product is a biosimilar of Cosentyx ®. The original drug has been approved in China for the treatment of moderate-to-severe plaque psoriasis in patie nts aged 6 years and older who are candidates for systemic therapy or phototherapy; ankylosing spondyli tis in adult patients who have had an inadequate response to conventional therapy; active psori atic arthritis in adult patients who have had an inadequate response or intolerance to prior conventional d isease-modifying antirheumatic drugs; moderate to severe hidradenitis suppurativa in adult patie nts; and active non-radiographic axial spondyloarthritis in adult patients who have had an inadequ ate response to non-steroidal anti- inflammatory drugs, with objective signs of inflammation i ndicated by elevated C-reactive protein and/ or magnetic resonance imaging evidence. – 1 – This marketing authorisation application is based on a Phas e I pharmacokinetic ( ‘‘PK’’) similarity conducted in healthy subjects and a Phase III equivalence st udy conducted in patients with psoriasis. The study results demonstrated that the Product exhibited h igh similarity to Cosentyx ® in terms of efficacy, safety, PK and immunogenicity profiles. Detaile d data will be published at upcoming academic conferences and in medical journals. By Order of the Board CSPC Pharmaceutical Group Limited CAI Dong Chen Chairman Hong Kong, 18 June 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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