HENLIUS (02696) announced that an international multi-center Phase 2 clinical study of HLX43 (a PD-L1 targeted antibody-drug conjugate) in patients with advanced non-small cell lung cancer (NSCLC) has completed first patient dosing in Australia. This Phase 2 clinical study is also being conducted simultaneously in mainland China and the United States.

This is an open-label, international multi-center Phase 2 clinical trial designed to evaluate the efficacy and safety of HLX43 in patients with advanced non-small cell lung cancer (NSCLC). The study consists of two stages: the first stage will conduct dose exploration to select an appropriate HLX43 dose for the second stage study; the second stage is a single-arm, multi-center Phase 2 clinical study.

The primary objective of this study is to evaluate the clinical efficacy of HLX43 in advanced non-small cell lung cancer (NSCLC). The primary endpoint is the objective response rate assessed by a blinded independent central review committee (BICR) according to RECIST v1.1 criteria.

HLX43 is a PD-L1 targeted antibody-drug conjugate (ADC) developed by the company through conjugation of a licensed novel DNA topoisomerase I inhibitor small molecule toxin-linker with the company's proprietary PD-L1 targeting antibody, intended for treatment of advanced/metastatic solid tumors.

In September 2025, updated Phase 1 clinical data for HLX43 was presented at the 2025 World Conference on Lung Cancer (WCLC). The study results demonstrated that HLX43 continued to show high response rates in patients with advanced solid tumors, particularly in the vast majority of later-line resistant non-small cell lung cancer (NSCLC) patients who had failed previous checkpoint inhibitor (CPI) and chemotherapy treatments, while maintaining good safety across all dose levels.

The investigator-assessed objective response rate (ORR) was 37.0%, with a disease control rate (DCR) of 87.0%. Among NSCLC squamous cell carcinoma patients who had previously received docetaxel as third-line or later anti-cancer treatment, the ORR was 30.0% (3/10 cases); in NSCLC squamous cell carcinoma patients in the 2.0 mg/kg HLX43 dose group, the ORR was 40.0%.

In the EGFR wild-type non-squamous NSCLC population, HLX43 demonstrated superior efficacy with a confirmed ORR of 46.7%; among these patients, those receiving 2.5 mg/kg HLX43 treatment achieved a confirmed ORR of 60.0%. Patients with brain metastases had a confirmed ORR of 36.4% and a disease control rate (DCR) of 100.0%.

Additionally, HLX43 achieved ORRs of 34.4% and 38.1% in PD-L1 positive (tumor proportion score (TPS) ≥ 1%) and PD-L1 negative (TPS < 1%) patients, respectively.

HLX43 is a PD-L1 targeted antibody-drug conjugate. As of the date of this announcement, no PD-L1 targeted antibody-drug conjugates have been approved for marketing globally.