VOLUNTARY ANNOUNCEMENT - ANTIBODY-DRUG CONJUGATE "SYSA1801" OBTAINS CLINICAL TRIAL APPROVAL IN THE U.S.

— 1 — Hong Kong Exchanges and Clearing Limited and The Stock Exchange 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 whatsoever for any loss howsoever arising from or in reliance upon the whole or any part of the contents of this announcement. CSPC PHARMACEUTICAL GROUP LIMITED ʮ̡ (Incorporated in Hong Kong with limited liability) (Stock code: 1093) VOLUNTARY ANNOUNCEMENT ANTIBODY-DRUG CONJUGATE “SYSA1801” OBTAINS CLINICAL TRIAL APPROVAL IN THE U.S. The board of directors (the “ Board”) of CSPC Pharmaceutical Group Limited (the “ Company ”, together with its subsidiaries, the “ Group”) is pleased to announce that “SYSA1801” (the “Product”), an antibody-drug conjugate developed by the Group, has obtained approval of its Investigational New Drug Application (IND) from the U.S. Food and Drug Administration (FDA) to conduct clinical trials for advanced pancreatic cancer with positive Claudin 18.2 expression. The Phase I clinical trial will evaluate the safety, tolerability, pharmacokinetics and preliminary efficacy of SYSA1801. SYSA1801 is novel (first-in-class) anti-Claudin 18.2 monoclonal antibody-drug conjugate. Preclinical in vitro and in vivo animal studies have demonstrated that the Product can effectively target tumor cells through anti-Claudin 18.2 antibody and trigger endocytosis, bringing the small molecule toxin into tumor cells to achieve anti-tumor effects. The preclinical studies have shown that the Product has excellent in vivo and in vitro activity and good safety for pancreatic cancer, providing a promising prospect of demonstrating good efficacy in clinical trials. The Product has been granted orphan-drug designation for the treatment of pancreatic cancer by the U.S. FDA in 2021. The Group will endeavor to push forward the clinical trials of the Product and strive to launch the Product as soon as possible. By order of the Board CSPC Pharmaceutical Group Limited Cai Dongchen Chairman Hong Kong, 16 July 2021 — 2 — As at the date of this announcement, the Board comprises Mr. CAI Dongchen, Mr. ZHANG Cuilong, Mr. WANG Zhenguo, Mr. PAN Weidong, Mr. WANG Huaiyu, Dr. LI Chunlei, Dr. WANG Qingxi, Mr. CHAK Kin Man and Dr. JIANG Hao as executive directors; and Mr. WANG Bo, Mr. CHEN Chuan, Prof. WANG Hongguang, Mr. AU Chun Kwok Alan and Mr. LAW Cheuk Kin Stephen as independent non-executive directors.

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