Core Viewpoint - The company has initiated a Phase 2 clinical trial for HLX43, a targeted PD-L1 antibody-drug conjugate, in patients with advanced non-small cell lung cancer (NSCLC) [1][2] Group 1: Clinical Trial Details - The Phase 2 clinical trial is an open-label, international, multicenter study aimed at evaluating the efficacy and safety of HLX43 in advanced NSCLC patients [1] - The study consists of two stages: the first stage focuses on dose exploration to select an appropriate dose for the second stage, which is a single-arm, multicenter Phase 2 clinical study [1] - The primary objective of the study is to assess the clinical efficacy of HLX43, with the main endpoint being the objective response rate (ORR) evaluated by a blinded independent central review committee (BICR) according to RECIST v1.1 criteria [1] Group 2: Clinical Data and Efficacy - Preliminary data from the Phase 1 clinical trial presented at the 2025 World Lung Cancer Conference (WCLC) showed HLX43 has a 37.0% ORR and an 87.0% disease control rate (DCR) in advanced solid tumors, particularly in NSCLC patients who have failed prior checkpoint inhibitors and chemotherapy [2] - In NSCLC patients who had previously received docetaxel as third-line or higher treatment, the ORR was 30.0% [2] - In the EGFR wild-type non-squamous NSCLC population, HLX43 demonstrated an ORR of 46.7%, with a confirmed ORR of 60.0% in patients receiving a 2.5 mg/kg dose [2] - Among patients with brain metastases, the confirmed ORR was 36.4% with a DCR of 100.0% [2] - The ORR for PD-L1 positive (TPS ≥ 1%) and PD-L1 negative (TPS < 1%) patients was 34.4% and 38.1%, respectively [2] Group 3: Market Context - As of the announcement date, there are no approved PD-L1 targeted antibody-drug conjugates available in the global market [3]

Shanghai Henlius Biotech, Inc. 上海復宏漢霖生物技術股份有限公司 （於中華人民共和國註冊成立的股份有限公司） （股份代號：2696） 自願公告 注射用HLX43（靶向PD-L1抗體－新型DNA拓撲異構酶I抑制劑 偶聯藥物）用於治療復發/轉移性食管鱗癌(ESCC)的 2期臨床研究於中國境內完成首例患者給藥 香港交易及結算所有限公司及香港聯合交易所有限公司對本公告的內容概不負責，對其準確性 或完整性亦不發表任何聲明，並明確表示概不就因本公告全部或任何部分內容而產生或因倚賴 該等內容而引致的任何損失承擔任何責任。 本研究為評估不同劑量HLX43在經一線標準治療失敗或不可耐受毒性的復發/ 轉移性食管鱗癌患者中的有效性和安全性的2期臨床試驗。篩選合格的受試者 將接受每3周一次(Q3W)HLX43治療。本研究主要目的是評估HLX43在復發/ 轉移性食管鱗癌中的臨床療效。次要目的是評估安全性和耐受性、藥代動力 學特徵及免疫原性、和潛在預測性生物標誌物。 1 C. 關於HLX43 HLX43是由本公司利用於2022年11月自蘇州宜聯生物醫藥有限公司許可引進 的新型DNA拓撲異構酶I抑制劑小分子毒 ...