HENLIUS (02696): The Phase 1 clinical study of the subcutaneous injection of HLX319, a biosimilar to pertuzumab and trastuzumab, has completed its first dosing in China.

Henlius (02696) announces that recently, the Phase 1 clinical study of HLX319, a biosimilar drug developed independently by the company, was completed with the first subject dosing in mainland China (excluding Hong Kong, Macau, and Taiwan). This study is a randomized, double-blind, single subcutaneous dose, parallel-controlled Phase 1 clinical study aimed at evaluating the pharmacokinetics (PK) characteristics, safety, tolerability, and immunogenicity of HLX319 in healthy male subjects in China compared to its reference drug Phesgo (marketed in Europe). Eligible subjects will be randomly assigned in a 1:1 ratio to receive a single subcutaneous dose of either HLX319 or Phesgo injection. The injection site will be the subcutaneous tissue of the thigh, with an injection time of approximately 5 minutes. The main endpoints of this study are the major PK parameters of pertuzumab and trastuzumab, including peak concentration (Cmax) and area under the concentration-time curve from 0 to infinity (AUC0-). Secondary endpoints include other PK parameters, safety endpoints, and immunogenicity endpoints. HLX319 is a biosimilar drug of the subcutaneous injection of pertuzumab trastuzumab, consisting of the active ingredients pertuzumab and trastuzumab and the excipient hyaluronidase (HLXTE-HAase02, a new recombinant human hyaluronidase developed independently by the company), intended for the adjuvant/neoadjuvant treatment of HER2-positive early or locally advanced breast cancer and the treatment of metastatic breast cancer. The subcutaneous injection of pertuzumab trastuzumab is a fixed-dose subcutaneous administration formulation composed of trastuzumab and pertuzumab, which can target HER2 at different epitopes, cooperatively blocking HER2 signal transduction and mediating antibody-dependent cellular cytotoxicity (ADCC) to exert antitumor effects. Specifically, trastuzumab can bind specifically to the extracellular domain IV of HER2, blocking receptor signal transduction and inhibiting tumor cell proliferation, while also mediating ADCC. Pertuzumab can bind specifically to the extracellular domain II of HER2, blocking HER2's ligand dimerization with other ErbB family members, resulting in cell growth arrest and apoptosis, while also mediating ADCC. According to the requirements of the biosimilar drug guidelines issued by the National Medical Products Administration (NMPA) and referencing the European Union's biosimilar drug guidelines, through pharmaceutical comparisons, preclinical pharmacodynamics, pharmacokinetics, and toxicology studies have proven that HLX319 is similar to the originator pertuzumab trastuzumab subcutaneous injection. In March 2026, the Phase 1 clinical trial application (INDs) for HLX319 was approved by the NMPA. According to data released by IQVIA MIDASTM (IQVIA is a global provider of professional information and strategic consulting services for the pharmaceutical and healthcare industry), in 2025, the global sales of the subcutaneous injection of pertuzumab trastuzumab were approximately 30.23 billion US dollars.