VOLUNTARY ANNOUNCEMENT - "SYHX1901 TABLETS" OBTAINS CLINICAL TRIAL APPROVAL FOR THE TREATMENT OF SEVERE COVID-19

– 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. (Incorporated in Hong Kong with limited liability) (Stock code: 1093) VOLUNTARY ANNOUNCEMENT “SYHX1901 TABLETS” OBTAINS CLINICAL TRIAL APPROV AL FOR THE TREATMENT OF SEVERE COVID-19 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 “SYHX1901 Tablets” developed by the Group has obtained approval granted by the National Medical Products Administration of the People’s Republic of China to conduct clinical trials for the treatment of adult patients with severe Coronavirus Disease 2019 (COVID-19) in China. COVID-19 is a contagious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS- CoV-2), which was announced as a pandemic on 11 March 2020. According to the statistics of the World Health Organization (WHO), as of 2 October 2022, over 615 million confirmed cases and 6.5 million deaths have been reported globally. Hospitalised severe patients will quickly develop COVID-19-associated acute respiratory distress syndrome (CARDS), leading to life-threatening respiratory failure. At the advanced stage of the clinical course, the excessive pulmonary inflammatory response is caused by large-scale tissue damage induced by the virus, which is related to the uncontrolled release of cytokines by inflammatory macrophages and granulocytes, and the dysregulation of immune/inflammatory response to SARS-CoV-2 may lead to further tissue damage and thrombosis. When COVID-19 advances to the stage characterised by hypoxemia and endothelial dysfunction, immunosuppression, anti-inflammatory and antithrombotic therapies may be more beneficial. – 2 – SYHX1901 tablet, a small-molecule compound developed by the Group and classified as a Class 1 chemical drug in China, is a globally innovative drug. It is a JAK/TYK2 inhibitor which inhibits key targets on the B cell and T cell-mediated signaling pathway related to inflammatory response. The JAK-STAT signaling pathway has a key role in the SARS-CoV-2-induced over-activation of inflammatory cytokine. JAK inhibitor can block the cytokine cascade amplification through the specific inhibition of JAK-STAT signaling pathway to inhibit the cytokine storm. SYHX1901 tablet has an innovative structure with its molecule having inhibitory activity against the JAK signaling pathway and showing good inhibitory effect on cytokine release induced by SARS-CoV-2 proteins, and is a potential therapy for the treatment of symptomatic SARS-CoV-2 infection. By order of the Board CSPC Pharmaceutical Group Limited CAI Dongchen Chairman Hong Kong, 23 November 2022 As at the date of this announcement, the Board comprises Mr. CAI Dongchen, Mr. ZHANG Cuilong, Mr. WANG Zhenguo, Mr. P AN 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, Mr. LAW Cheuk Kin Stephen and Ms. LI Quan as independent non- executive directors.

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