VOLUNTARY ANNOUNCEMENT - BIOLOGIC LICENSE APPLICATION FOR NARLUMOSBART FOR INJECTION (JMT103) APPROVED BY THE NMPA

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. (Incorpor ated in H ong Kong with limi ted liabi lity) (Stock co de: 1093) VOLUNTARY ANNOUNCEMENT BIOLOGIC LICENSE APPLICATION FOR NARLUMOSBART FOR INJECTION (JMT103) APPROVED BY THE NMPA 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 biologic license application (“BLA”) for class 1 new drug Narlumosbart for Injection (brand name: Jinlisheng (津立 生)) (JMT103) (the“Product”) developed byShanghai JMT-Bio Technology Co.,Ltd.*(上海津曼特 生物科技有限公司), a subsidiary of the Company, for the treatment of giant cell tumor of bone that is unresectable or where surgical resection is likely to result in severe morbidity has been approved by the National Medical Products Administration (NMPA) of the People’s Republic of China. The Product is the first IgG4 subtype fully human monoclonal antibody against RANKL obtaining marketing approval in the world. At present, denosumab, an IgG2 subtype, is another marketed drug against the same target in the world. Compared with denosumab, the Product has significant enhancement in uniformity and quality controllability. Subcutaneous injection is used to administer the Product. It can block the binding of RANKL to the membrane RANK receptors of cells such as osteoclast precursor cells, osteoclasts and osteoclast-like giant cells, thereby inhibiting the differentiation, maturation and functional activity of the above cells mediated by RANKL-RANK signaling pathway. It is expected to treat diseases associated with the activation of RANKL-RANK signaling pathway, such as giant cell tumor of bone, osteoporosis, tumor bone metastasis. - 1 - The granting of marketing approval for this new drug is mainly based on two pivotal clinical studies (JMT103CN03 Phase II Pivotal Clinical Study and JMT103CN03-1 Real-World Study) in the treatment of unresectable or surgically difficult giant cell tumor of bone. The clinical studies demonstrated that JMT103 has abetter clinical efficacy inthe treatment of unresectable or surgically difficult giant celltumor ofbonewithatumor response rateof93.3%, andatrend higher thanthat of the denosumab group. At the same time, JMT103 showed a good safety profile with controllable safety risks. This marketing approval is for the first indication of the Product. At present, there are also other indications under development, including tumor bone metastasis and osteoporosis. By Order of the Board CSPC Pharmaceutical Group Limited CAI Dongchen Chairman Hong Kong, 6 September 2023 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, Mr. LAW Cheuk Kin Stephen and Ms. LI Quan as independent non-executive directors. - 2 -

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