The 2025 American Society of Clinical Oncology (ASCO) Annual Meeting will be held in Chicago, USA, from May 30 to June 3. Henlius will showcase about 20 latest/updated research achievements on innovative products at the conference, covering HLX43 (PD-L1-targeted ADC), HLX22 (anti-HER2 monoclonal antibody), and HANSIZHUANG (serplulimab, anti-PD-1 monoclonal antibody). 

HLX43 (PD-L1-Targeting ADC)

HLX43 is a novel PD-L1-targeting ADC, 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 integrates targeted cytotoxic delivery and immune checkpoint activation through PD-L1/PD-1 blockade. Upon binding to PD-L1-expressing tumor cells, HLX43's cytotoxic payload can be delivered into tumor cells via dual mechanisms—First, the ADC undergoes 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 activates immune modulation and blocks immune checkpoints, driving synergistic antitumor efficacy.Preclinical studies have demonstrated that, HLX43 exhibits significant antitumor activity both as a monotherapy and in combination therapies, potentially offering a promising therapeautic option for tumour patients who do not respond to or develop resistance to PD-1/PD-L1-targeted therapy.

HLX22 (anti-HER2 mAb)

HLX22, an innovative anti-HER2 mAb, can bind to HER2 extracellular subdomain IV at a binding site different from that of trastuzumab, which allows simultaneous binding of HLX22 and trastuzumab to HER2 dimers (HER2 homodimer and HER2/EGFR heterodimer) on tumour cell surface, thereby promoting the internalization and HER2 dimer degradation. The phase 2 clinical data on the combination of HLX22 and HANQUYOU (trastuzumab, trade name: HERCESSI™ in the U.S., Zercepac^® in Europe) demonstrate that the addition of HLX22 to HANQUYOU plus chemotherapy significantly improves survival and anti-tumour efficacy in first-line treatment of HER2-positive gastric/gastroesophageal junction cancer (GC/GEJC) patients, with manageable safety profiles. At present, the Investigational New Drug (IND) applications for HLX22-GC-301, a phase 3 clinical study aims to evaluate the efficacy and safety of HLX22 in combination with trastuzumab and chemotherapy for the first-line treatment of patients with HER2-positive metastatic GC/GEJC, have been approved by regulatory authorities in China, the U.S, Japan and Australia, etc., and this international study has been initiated in multiple countries and regions worldwide and has completed its first patient dosing globally. Furthermore, HLX22 has received orphan drug designation (ODD) in 2025 from the U.S. Food and Drug Administration (FDA) for the treatment of gastric cancer. Currently, the therapeutic scope of HLX22 has further expanded to the field of breast cancer apart from its exploration in gastric cancer, potentially providing new treatment options for broader tumour patients population.

HANSIZHUANG（serplulimab, anti-PD-1 mAb）

HANSIZHUANG (recombinant humanized anti-PD-1 monoclonal antibody injection, generic name: serplulimab injection) is the first anti-PD-1 mAb for the first-line treatment of SCLC and has been approved in China, the EU and several SEA countries. Focusing on lung and gastrointestinal cancer, the synergy of HANSIZHUANG with in-house products of the company and innovative therapies are being actively promoted. Up to date, HANSIZHUANG has been approved by the National Medicinal Products Administration (NMPA) for the treatment of squamous non-small cell lung cancer (sqNSCLC), extensive-stage small cell lung cancer (ES-SCLC), esophageal squamous cell carcinoma (ESCC) and non-squamous non-small cell lung cancer (nsNSCLC). Serplulimab was granted orphan drug designations by the FDA and the EC for the treatment of SCLC, and its bridging head-to-head trial in the United States to compare HANSIZHUANG to standard of care atezolizumab (anti-PD-L1 mAb) for the first-line treatment of ES-SCLC is well under way.

The results of 4 pivotal trials of HANSIZHUANG were published in the Journal of the American Medical Association (JAMA), Nature Medicine, Cancer Cell and British Journal of Cancer, respectively. Furthermore, HANSIZHUANG was respectively recommended by the CSCO Guidelines for Small Cell Lung Cancer, the CSCO Guidelines for Non-Small Cell Lung Cancer, the CSCO Guidelines for Esophageal Cancer, the CSCO Clinical Practice Guidelines on Immune Checkpoint Inhibitor, the China Guidelines for Radiotherapy of Esophageal Cancer, and other definitive guides, providing valuable references for clinical diagnosis and treatment of tumours.