VOLUNTARY ANNOUNCEMENT - CPO301 GRANTED THE THIRD FAST TRACK DESIGNATION BY U.S. FDA FOR THE TREATMENT OF ADULT PATIENTS WITH NSCLC

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 CPO301 GRANTED THE THIRD FAST TRACK DESIGNATION BY U.S. FDA FOR THE TREATMENT OF ADULT PATIENTS WITH NSCLC The board of directors (the ‘‘Board ’’) of CSPC Pharmaceutical Group Limited (the ‘‘Company ’’, together with its subsidiaries, the ‘‘Group ’’) is pleased to announce that CPO301 (also known as SYS6010 in China), a first-in-class epidermal growth facto r receptor ( ‘‘EGFR ’’) antibody drug conjugate (ADC) developed by the Group, has been granted the third Fast Track designation by the U.S. Food and Drug Administration ( ‘‘FDA’’) for the treatment of adult patients with advanced or metastatic non-squamous non-small cell lung cancer (Nsq-N SCLC) without EGFR mutations or other actional genomic alterations (AGA), with prior disease pro gression on platinum-based chemotherapy and an anti-PD-(L)1 antibody. Previously, CPO301 received two Fast Track designations fr om the FDA: the first in June 2023 for the treatment of patients with metastatic non-small cell lung c ancer ( ‘‘NSCLC ’’) harboring EGFR mutations who are relapsed/refractory to or ineligible for EGFR targeting therapy such as a 3rd- generation EGFR inhibitors including Osimertinib; and the second in September 2024 for the treatment of patients with recurrent or metastatic squamous non-smal l cell lung cancer (Sq-NSCLC) with EGFR overexpression that has progressed on or after treatment wi th platinum-based chemotherapy and anti- PD-(L)1 therapy. Lung cancer is the leading cause of cancer incidence and mort ality worldwide, with an estimated 2.5 million new cases and 1.8 million deaths globally. Activati ng EGFR gene mutations and overexpression of EGFR protein are drivers in lung cancer with EGFR mutation s as well as in histopathologic subtypes that do not possess EGFR mutations but express elevated leve ls of wild-type EGFR protein, including both squamous cell carcinoma and adenocarcinoma. The Fast T rack designations in all subtypes of NSCLC were granted based on promising clinical efficacy dat a, showing more promising activity as compared to currently available therapies in NSCLC and othe r tumor types. – 1 – CPO301 is a humanized monoclonal antibody, optimized from c etuximab, and conjugated with a topoisomerase I inhibitor. It is currently undergoing clin ical studies simultaneously in China and the U.S. The granting of Fast Track designation by the FDA will fa cilitate and expedite the development and registration of CPO301 in the U.S. and globally. By order of the Board CSPC Pharmaceutical Group Limited CAI Dongchen Chairman Hong Kong, 19 May 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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