HENLIUS (02696) announced that the company has recently completed first patient dosing in China (excluding Hong Kong, Macau and Taiwan) for an international multi-center Phase 1 clinical trial of its independently developed pembrolizumab biosimilar HLX17 (Recombinant Anti-PD-1 Humanized Monoclonal Antibody Injection) in patients with various resected solid tumors. The company will also conduct this international multi-center clinical trial in the United States, Europe, Australia and other countries/regions when conditions permit.

This is a multi-center, randomized, double-blind, parallel-controlled Phase 1 clinical study designed to evaluate the similarity of pharmacokinetic (PK) characteristics, efficacy, safety and immunogenicity between HLX17 and KEYTRUDA® (U.S. marketed) in subjects with various resected solid tumors (including non-small cell lung cancer, melanoma or renal cell carcinoma).

Eligible subjects will be randomized 1:1 to Group A and Group B. Group A subjects will receive HLX17 treatment once every 3 weeks; Group B subjects will receive KEYTRUDA® treatment once every 3 weeks for the first 8 cycles (24 weeks), then switch to HLX17 treatment. All subjects will continue treatment until 12 months post-randomization (approximately 17 cycles) or until investigator-assessed disease recurrence, death, initiation of new anti-tumor treatment, occurrence of intolerable drug toxicity, withdrawal of informed consent, or study termination (whichever occurs first).

The primary endpoints of this study are the area under the serum drug concentration-time curve from 0 to 21 days after first dosing (AUC0-21d) and the area under the serum drug concentration-time curve within a single dosing interval at steady state after the 6th dosing (AUCss). Secondary endpoints include other PK parameters, efficacy, safety and immunogenicity.

HLX17 is the company's independently developed pembrolizumab biosimilar, with potential indications including melanoma, non-small cell lung cancer, esophageal cancer, head and neck squamous cell carcinoma, colorectal cancer, hepatocellular carcinoma, biliary tract cancer, triple-negative breast cancer, microsatellite instability-high or mismatch repair deficient tumors, gastric cancer and other indications already approved for the originator drug.

The binding of the PD-1 receptor expressed on T cells to its ligands PD-L1 and PD-L2 can inhibit T cell proliferation and cytokine production. The upregulation of PD-1 ligands in some tumor cells can inhibit activated T cell immune surveillance of tumors through this pathway signaling. Pembrolizumab is a monoclonal antibody that can bind to the PD-1 receptor, blocking the interaction between PD-1 and PD-L1/PD-L2, thereby relieving PD-1 pathway-mediated immune suppression, including anti-tumor immune responses, and improving the immune system's ability to kill tumor cells.

In September 2024, the clinical trial application for HLX17 was approved by the National Medical Products Administration (NMPA). In September 2025, the Investigational New Drug (IND) application for HLX17's Phase 1 clinical trial in patients with various resected solid tumors was approved by the U.S. Food and Drug Administration (FDA).