Shanghai, China, May 21, 2026 — Shanghai Henlius Biotech, Inc. (2696.HK) today announced that the first patient in the European Union (EU) has been successfully dosed in Spain in the international multi-center Phase 2 clinical trial (HLX43-NSCLC201) evaluating HLX43, an innovative programmed death-ligand 1 (PD-L1) targeting antibody-drug conjugate (ADC), for the treatment of advanced non-small cell lung cancer (NSCLC). The HLX43-NSCLC201 study has now been fully initiated across China, the EU, the United States, Japan, and Australia, marking comprehensive coverage of major global markets for the clinical development of this first-in-class PD-L1 ADC. Building on its broad efficacy and favorable safety profile across diverse patient populations, the latest research results of HLX43 in NSCLC are also scheduled for a highly anticipated oral presentation at the 2026 ASCO Annual Meeting.

Lung cancer is the most common cancer worldwide in terms of incidence and mortality. According to GLOBOCAN 2022, there were over 2.48 million new cases of lung cancer globally in 2022, accounting for 12.4% of all new cancer cases.¹ The majority of lung cancer patients are diagnosed at advanced stages,² indicating a significant unmet clinical need. Non-small cell lung cancer (NSCLC) is the most common type of lung cancer (approximately 85%). By histology, NSCLC can be classified into squamous cell carcinoma (approximately 30%), adenocarcinoma (approximately 50%) and other subtypes including large cell carcinoma. EGFR wild-type cases account for 70%-85% of all NSCLC patients, including nearly all squamous cell carcinoma cases and 50-55% of adenocarcinoma cases.³ Currently, the treatment landscape of EGFR wild-type NSCLC remains limited by a scarcity of highly effective options, particularly in second-line and later (2L+) therapy, where docetaxel-based chemotherapy continues to serve as the standard of care despite its suboptimal efficacy.^4,5

HLX43 is a broad-spectrum anti-tumor ADC candidate targeting PD-L1, composed of a fully humanized anti-PD-L1 IgG1 antibody, a novel tripeptide linker and topoisomerase inhibitor payload. The drug-to-antibody ratio (DAR) is around 8. Its mechanisms of action integrate targeted cytotoxic delivery and immune checkpoint activation through PD-L1/PD-1 blockade. Upon bonding to tumor cells with PD-L1 expression, the cytotoxic payload of HLX43 will be delivered into tumor cells via dual mechanisms. HLX43 will undergo receptor-mediated endocytosis, releasing the cytotoxic payload intracellularly via linker cleavage, and the payload further diffuses into neighboring tumor cells via bystander effect, thereby blocking DNA replication and triggering tumor cell apoptosis. Meanwhile, the anti-PD-L1 antibody of HLX43 activates immune modulation and blocks immune checkpoints, driving synergistic anti-tumor efficacy. The results from the phase 1 clinical trial of HLX43 has been first released at the 2025 ASCO Annual Meeting, demonstrating manageable safety profile and encouraging efficacy in various solid tumors especially in patients with NSCLC, including squamous and non-squamous NSCLC patients (sqNSCLC and nsqNSCLC), patients with or without EGFR mutation, patients with or without brain/liver metastasis, and PD-L1 positive or negative patients. In November 2025, updated data in lung cancer—integrating preliminary results from the HLX43-NSCLC201 study—were released. This analysis established 2.0 mg/kg or 2.5 mg/kg as the recommended Phase 2/3 dose (RP2/3D) for HLX43 in NSCLC, consistently validating the drug's efficacy and safety at these dose levels.

Henlius is vigorously advancing the clinical development of HLX43. An international multi-center Phase 2/3 study (HLX43-NSCLC302) for advanced squamous NSCLC (sqNSCLC) is slated to launch across multiple countries, including China, the US, and Japan. The Phase 3 portion of this study is poised to become the first pivotal registrational trial for HLX43 in NSCLC, potentially offering a novel therapeutic option for the hard-to-treat population of sqNSCLC patients who have failed prior standard therapies. Beyond NSCLC, the company is actively exploring the potential of HLX43 across various solid tumors, including esophageal squamous cell carcinoma (ESCC), cervical cancer, breast cancer, gastric/gastroesophageal junction (G/GEJ) cancer, and head and neck squamous cell carcinoma (HNSCC). In addition to monotherapy, clinical trials investigating HLX43 in combination with other agents are ongoing to further explore the synergistic anti-tumor efficacy of ADCs with complementary therapies. HLX43 demonstrates the clinical potential to overcome primary or acquired resistance to PD-1/L1 immunotherapies and offers potential efficacy for patients who have failed chemotherapy or TKI treatments, bringing hope for a new generation of treatments to patients with advanced or metastatic solid tumors.

About HLX43-NSCLC201

This is an open-label, multi-centre, international phase 2 clinical study to evaluate HLX43 in patients with advanced non-small cell lung cancer (NSCLC). This study aims to evaluate the efficacy and safety of HLX43 in advanced non-small cell lung cancer (NSCLC) patients. It consists of two parts: Part 1, which focuses on dose exploration to identify the optimal HLX43 dosage for Part 2; and Part 2, which is a single-arm, multi-centre phase 2 clinical trial. The primary objective of this study is to evaluate the clinical efficacy of HLX43 in advanced non-small cell lung cancer (NSCLC) patients. The primary endpoint of the study is objective response rate evaluated by the Blinded Independent Central Review (BICR) according to RECIST v1.1.