VOLUNTARY ANNOUNCEMENT - SIROLIMUS FOR INJECTION (ALBUMIN-BOUND) WAS GRANTED BREAKTHROUGH THERAPY DESIGNATION 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 SIROLIMUS FOR INJECTION (ALBUMIN-BOUND) WAS GRANTED BREAKTHROUGH THERAPY DESIGNATION 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 Sirolimus for Injection (albumin-bound) (the ‘‘Product ’’) developed by the Group has been granted Breakthrough Thera py Designation by the National Medical Products Administrati on (NMPA) of the People ’s Republic of China for the intended indication of monotherapy for malign ant perivascular epithelioid cell tumor (PEComa) (the ‘‘Indication ’’). Sirolimus, also known as rapamycin, is a commonly used speci fic mTOR inhibitor. The oral formulation of sirolimus previously approved for marketin g is indicated primarily for the prevention of organ rejection in kidney transplant patients. The Product utilises special technology to encapsulate sirolimus into human serum albumin to overcome the shortcom ing that oral formulation fails to deliver sufficient concentration of drug to the target site and has a chieved administration of sirolimus by injection without hormone pretreatment. Meanwhile, the Pr oduct has expanded the field of application of sirolimus, thus having the potential for treating a serie s of diseases caused by the mTOR signaling pathway. Currently, the Product is undergoing multiple phase II and I II clinical studies in China for the treatment of solid and hematological tumors, including breast cancer , soft tissue sarcoma, lung cancer, and kidney cancer. Breast cancer ranks first among malignant tumors in women, with approximately 2.3 million new cases of female breast cancer globally, and there is a sig nificant unmet clinical need for patients with HR+/HER2- advanced breast cancer after failure of trea tment with CDK4/6 inhibitors. The Product, in combination with endocrine therapy, is the firs t mTOR inhibitor in China that undergoes clinical trials in patients with HR+/HER2- advanced breast cancer who develop resistance to CDK4/6 inhibitors, and the Group has already submitted an applicat ion for communication and exchange of pivotal phase III clinical trials to the regulatory authori ty. – 1 – There is no standard treatment for malignant PEComa in China , representing an unmet clinical need. The Product has now entered the pivotal phase III clinical en rollment stage, with clinical data already confirming that its monotherapy efficacy was significantl y better than historical data. The Breakthrough Therapy Designation granted to the Product will further exp edite its development progress, making it potentially become the first standard treatment for the Ind ication in China. By order of the Board CSPC Pharmaceutical Group Limited CAI Dongchen Chairman Hong Kong, 28 February 2025 As at the date of this announcement, the Board comprises Mr. C AI Dongchen, Mr. ZHANG Cuilong, Mr. WANG Zhenguo, Mr. PAN Weidong, Mr. WANG Huaiyu, Dr. LI Chu nlei, Dr. YAO Bing, Mr. CAI Xin and Mr. CHEN Weiping as executive directors; and Mr. WANG Bo, Mr. CHEN Chuan, Prof. WANG Hongguang, Mr. AU Chun Kwok Alan, Mr. LAW Cheuk Kin Steph en and Ms. LI Quan as independent non-executive directors. – 2 –

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