VOLUNTARY ANNOUNCEMENT - RESULTS OF THE PHASE III CLINICAL TRIAL OF ENZESHU (SUVEMCITUG FOR INJECTION) FOR THE TREATMENT OFPLATINUM-RESISTANT OVARIAN CANCER WERE PRESENTED AT THE ASCO ANNUAL MEETING

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 Simcere Pharmaceutical Group Limited先声药业集团有限公司 (Incorporated in Hong Kong with limited liability) (Stock code: 2096) VOLUNTARY ANNOUNCEMENT RESULTS OF THE PHASE III CLINICAL TRIAL OF ENZESHU (SUVEMCITUG FOR INJECTION) FOR THE TREATMENT OF PLATINUM-RESISTANT OVARIAN CANCER WERE PRESENTED AT THE ASCO ANNUAL MEETING This announcement is made by Simcere Pharmaceutical Group Limited (the “Company” together with its subsidiaries the “Group”) on a voluntary basis to inform shareholders and potential investors of the Company about the latest business development of the Group.The board (the “Board”) of directors (the “Directors”) of the Company is pleased to announce that on June 1 2024 the latest data of the phase III clinical trial of ENZESHU (Suvemcitug for injection) combined with chemotherapy (the “Experimental Arm”) versus placebo combined with chemotherapy (the “Control Arm”) in patients with recurrent platinum-resistant epithelial ovarian fallopian tube or primary peritoneal cancer (the “SCORES Study”) were presented through an oral report of the late-breaking abstract (Abstract No. LBA5516) at the American Society of Clinical Oncology (ASCO) Annual Meeting. The study data demonstrated that: (1) As assessed by the Blinded Independent Review Committee (the “BIRC”) among the full analysis population (i.e. intent-to-treat population ITT) the progression-free survival (the “PFS”) of the Experimental Arm was significantly extended compared to the Control Arm (the median PFS: 5.49 months vs. 2.73 months hazard ratio[HR] 0.46 P<0.0001). – 1 –(2) Across all pre-defined subgroups (age ECOG score presence of ascites sum of the diameters of baseline target lesions number of prior lines of therapy platinum-free interval number of prior systemic therapies presence of prior anti-angiogenic therapy platinum refractory and combination chemotherapy regimen by investigator’s choice) positive results and significant improvements in PFS were observed in efficacy analyses. (3) Among the 421 subjects enrolled in the SCORES Study 50.1% has been treated with VEGF pathway-targeted therapy previously and 48.9% has been treated with PARP inhibitors previously which was in line with the characteristics of the distribution of frontline treatments in current clinical practices. The study results suggested that among the population with prior use of VEGF and/or PARP inhibitors suvemcitug in combination with chemotherapy can improve the PFS of patients significantly. (4) As of the analysis date of primary endpoint the data of overall survival (the “OS”) as the key secondary endpoint were immature and the median follow-up duration of the two groups was 14.36 months and 14.26 months respectively. The results suggested that the OS of the Experimental Arm has shown a trend of benefit compared to the Control Arm (the median OS: 16.07 months vs. 14.88 months hazard ratio [HR] 0.79 P=0.1244). (5) Among other secondary efficacy endpoints the data of the Experimental Arm compared to the Control Arm demonstrated that: the median PFS assessed by investigators was 5.39 months vs. 2.46 months the objective response rates (the “ORR”) as assessed by the BIRC was 26.0% vs. 12.1% the ORR as assessed by the investigators was 23.1% vs. 8.6% and the DCR and DOR as assessed by the BIRC and investigators have also shown consistent benefits. (6) Suvemcitug in combination with chemotherapy has a good overall safety profile and there is no new safety signals compared to the other drugs of the same class.– 2 –ABOUT THE SCORES STUDY The SCORES Study (NCT04908787) is a multi-center randomized double-blinded and placebo-controlled phase III clinical trial in China to evaluate the efficacy and safety of ENZESHU (Suvemcitug for injection) in combination with investigator’s choice of chemotherapy (paclitaxel liposomal doxorubicin or topotecan) in the treatment of platinum-resistant ovarian cancer (the “PROC”) as compared with placebo in combination with chemotherapy. The SCORES Study is led by the Cancer Hospital Chinese Academy of Medical Sciences and has enrolled 421 patients with recurrent epithelial ovarian cancer fallopian tube cancer and primary peritoneal cancer who failed to be treated with platinum chemotherapy regimen at 55 study sites in China from June 2021 to June 2023. On January 3 2024 the SCORES Study met its primary endpoint PFS. ABOUT SUVEMCITUG Suvemcitug is a new-generation recombinant humanized anti-VEGF rabbit monoclonal antibody developed by the Group and Apexigen Inc. (“Apexigen” now part of Pyxis Oncology Inc.). Pre-clinical studies have shown that suvemcitug has higher affinity and anti-tumor efficacy than Bevacizumab at the same dose in multiple tumor models. The phase Ib clinical studies of suvemcitug conducted in China for the treatment of ovarian cancer preliminary demonstrated its favorable safety profile and efficacy signals. On March 15 2024 the New Drug Application of suvemcitug for injection was accepted by the National Medical Products Administration of China (NMPA). The indication is suvemcitug combined with chemotherapy for the treatment of recurrent platinum-resistant ovarian fallopian tube or primary peritoneal cancer. It is expected to provide a new treatment option for PROC which is a long-standing disease that seriously threatens women’s lives and health.– 3 –ABOUT THE COMPANY The Company is an innovation and R&D-driven pharmaceutical company and has established a “State Key Laboratory of Neurology and Oncology Drug Development”. The Company focuses on the therapeutic areas of oncology nervous system autoimmune and anti-infection with forward-looking layout of disease areas that may have significant clinicalneeds in the future aiming to achieve the mission of “providing today’s patients withmedicines of the future”. Driven by its in-house R&D efforts and synergistic innovation the Company has established strategic cooperation partnerships with many innovative companies and research institutes.By order of the Board Simcere Pharmaceutical Group Limited Mr. Ren Jinsheng Chairman and Chief Executive Officer Hong Kong June 2 2024 As at the date of this announcement the Board comprises Mr. REN Jinsheng as the Chairman and executive Director Mr. TANG Renhong Mr. WAN Yushan and Ms. WANG Xi as the executive Directors; and Mr. SONG Ruilin Mr. WANG Jianguo Mr. WANG Xinhua and Mr. SUNG Ka Woon as the independent non-executive Directors.–4–