Recently, Shanghai Henlius Biotech, Inc. (2696.HK) announced that the first subject has been dosed for a phase 2 clinical trial of HLX43 for Injection (HLX43-ESCC201), the novel Programmed Death-Ligand 1 (PD-L1)-targeting antibody-drug conjugate (ADC) that developed by the company based on the collaboration with MediLink Therapeutics, for the treatment of patients with recurrent/metastatic esophageal squamous cell carcinoma (ESCC). At present, no PD-L1 targeting ADC has been approved for marketing globally, and only SGN-PDL1V from Pfizer is about to innitiate a Phase 3 clinical trial. HLX43 is the second PD-L1-targeting ADC to enter clinical trial globally.
Immune checkpoint inhibitors represented by PD-1/PD-L1 monoclonal antibodies have emerged in recent years and revolutionised all lines of treatment for tumour patients. However, there are still many patients with positive PD-L1 expression who do not respond to or develop resistance to PD-1/PD-L1-targeted therapy[1]. To date, there has been no subsequent-line treatment for patients who are resistant to PD-1/L1 immunotherapy or failed to benefit from the standard treatments including immunotherapy, indicating a significant unmet medical need to further improve the clinical benefits for these patients. As a novel targeting therapy with the most prominent anti-tumour efficacy, ADCs have shown preliminary therapeutic potential in the treatment of multiple advanced solid tumours, such as breast cancer(BC), lung cancer(LC), esophageal cancer(EC) and gastric cancer(GC) ,making it a promising therapeutic in solid tumours[2]. PD-L1 is expressed in patients across a broad spectrum of tumour types including non-small cell lung cancer (NSCLC), colorectal cancer (CRC), triple negative breast cancer (TNBC), squamous cell carcinoma and displays limited expression on normal tissues, highlighting the potential of PD-L1 as a target for ADCs, which may bring new options for cancer treatment[3].
HLX43 is one of the first ADC candidates of Henlius to enter into clinical development. Combining the selectivity of targeted monoclonal antibodies with the highly potent cytotoxic agent, HLX43 could exert anti-tumour effects through specific binding to the PD-L1 expressed on the surface of tumour cells and release cytotoxic payloads after internalisation by the cancer cells. In 2023, the application for phase 1 clinical trial of HLX43 for the treatment of advanced/metastatic solid tumours was approved by the China National Medical Products Administration (NMPA) and the U.S. Food and Drug Administration (FDA), respectively. And the first patient has been dosed in this trial in November 2023 in the Chinese Mainland. In December 2024, the application for a phase 1b/2 clinical trial of HLX43 for the monotherapy or combination therapy of advanced/metastatic solid tumours has been approved by the NMPA. Several non-clinical studies and the phase 1 clinical trial have shown that, HLX43 has good anti-tumour effects and a favorable tolerability profile in non-small cell lung cancer (NSCLC) , cervical cancer (CC), ESCC, hepatocellular carcinoma (HCC), and other tumour types that were PD-1/L1 mAb-resistant. The results of the pre-clinical studies were published as poster presentation at the 2023 European Society of Medical Oncology (ESMO) Congress. Based on this, Henlius plans to initiate phase 2 clinical trials of HLX43 for potential solid tumour indications including ESCC, CC, HCC, nasopharyngeal carcinoma(NPC), head and neck squamous cell carcinoma (HNSCC) and non-small cell lung cancer (NSCLC)，to further evaluate the efficacy and safety of HLX43 in patients.
With a particular focus on addressing the unmet medical needs, Henlius will further take efforts to accelerate the R&D of more cutting-edge therapeutic options and promote the layout of our innovative portfolio based on the company’s competitive edge of an integrated antibody drug R&D platform, bringing more high-quality and affordable therapeutics for patients worldwide.
【Reference】
[1] Attili I, et al. Strategies to overcome resistance to immune checkpoint blockade in lung cancer[J]. Lung cancer: Journal of the International Association for the Study of Lung Cancer, 2021(154-):154.
[2] He J, Zeng X, Wang C, Wang E, Li Y. Antibody-drug conjugates in cancer therapy: mechanisms and clinical studies. MedComm (2020). 2024 Jul 28;5(8):e671.
[3] Kwan B, et al. 783 SGN-PDL1V, a novel, investigational PD-L1-directed antibody-drug conjugate for the treatment of solid tumors[J]. 2021.
About HLX43-ESCC201
This study is a phase 2 clinical trial designed to evaluate the efficacy and safety of different doses of HLX43 in patients with recurrent/metastatic esophageal squamous cell carcinoma (ESCC) who have failed or are intolerant to first-line standard treatment. Eligible subjects will receive HLX43 every 3 weeks (Q3W). The primary objective of this study is to assess the clinical efficacy of HLX43 in recurrent/metastatic ESCC. Secondary objectives include evaluating safety and tolerability, pharmacokinetic characteristics and immunogenicity, and potential predictive biomarkers.