Shanghai Henlius Biotech, Inc. announced that, recently, the first patient has been dosed in a phase 1 clinical study of HLX42 for injection (antibody- drug conjugate targeting EGFR with novel DNA topoisomerase I inhibitor) ("HLX42") for the treatment of advance/metastatic solid tumours in mainland China (excluding Hong Kong, Macau and Taiwan regions, the same as below). This open-label, dose-escalation, first-in-human phase 1 clinical trial aims to evaluate the safety and tolerability of HLX42 in patients with advanced/metastatic solid tumours. Patients will receive HLX42 intravenously every three weeks at seven dose levels (0.1 mg/kg, 0.3 mg/kg, 0.6 mg/kg, 1.2 mg/kg, 2.0 mg/kg, 3.0 mg/kg, and 4.0 mg/kg) following a "3+3" dose escalation design.

The dose-limiting toxicity ("DLT") observation period is three weeks after the first dose of HLX42. The primary endpoints of this study were the proportion of patients with DLT events in each dose cohort during the DLT observation period, and the maximum tolerated dose (MTD) of HLX42; the secondary endpoints include safety, pharmacokinetic parameters, immunogenicity, preliminary efficacy, pharmacodynamic measures, and potential predictive biomarkers and drug-resistance biomarkers. HLX42 is an antibody-drug conjugate (ADC) targeting EGFR developed by the Company licensed-in from MediLink Therapeutics (Suzhou) Co.

Ltd. in November 2022, with monoclonal antibody targeting EGFR independently developed by the Company, which is designed for the treatment of advanced/metastatic solid tumours. HLX42 can specifically bind to human EGFR target antigen and release the small-molecule payload in tumour, then kill tumour cells. Nonclinical pharmacology, pharmacokinetics and safety evaluation have proved that HLX42 could inhibit tumour growth and showed a favorable safety profile.

In October 2023 and November 2023, applications for phase 1 clinical trial of HLX42 for the treatment of advanced/metastatic solid tumours were approved by the National Medical Products Administration (NMPA) and the United States Food and Drug Administration (the "FDA"), respective. In December 2023, HLX42 for the treatment of patients with advanced or metastatic EGFR-mutated non-small cell lung cancer whose disease has progressed on a third-generation EGFR tyrosine kinase inhibitor has been granted the Fast Track Designation by FDA.