Shanghai, China, September 20th, 2020-Shanghai Henlius Biotech, Inc. (2696.HK) announced that the first patient was dosed in China in a phase 1 clinical trial of the Company?s pertuzumab biosimilar HLX11, a recombinant anti-human epidermal growth factor receptor 2 (HER2) subdomain II humanized monoclonal antibody injection.

HLX11 was independently developed by Henlius with the pertuzumab originator as reference drug and the development is in accordance with China's biosimilar guidelines. HLX11 can be potentially used for the treatment of HER2-positive metastatic breast cancer and early breast cancer. HER2 belongs to the epidermal growth factor receptor family. Proteins of this family can activate signal transduction pathways associated with cell growth and proliferation by forming homodimer or heterodimer, and the abnormal activation of these transduction pathways are proved to be correlated with tumorigenesis^[1-2]. HER2 positive (HER2 protein overexpressing or her2 gene amplification) breast cancer takes up 20%-25% of all breast cancer cases and is a major subtype of breast cancer^[3]. HLX11 can specifically bind with the subdomain II of HER2 extracellular domain and inhibit the herterodimerisation of HER2 and other HER family receptors, i.e. EGFR, HER2 and HER4. This will inhibit signal transduction of relevant pathways and lead to stop of growth and apoptosis of tumour cells. In the meantime, HLX11 can also enhance the tumour-killing activity of immune cells via antibody-dependent cell cytotoxicity.

Clinical data demonstrated that combining pertuzumab with trastuzumab and chemotherapy can decrease the risk of recurrence or death for HER2 positive breast cancer patients[4-5]. In January 2020, the clinical trial application of HLX11 has been approved by the National Medical Products Administration (NMPA). HLX11 can be potentially used in combination with trastuzumab and chemotherapy as neoadjuvant or adjuvant treatment for HER2 positive early breast cancer and in combination with trastuzumab and docetaxel for the treatment of patients with HER2 positive metastatic or unresectable locally recurrent breast cancer patients.

This phase 1 study is a randomised, double-blind, single-dose, parallel-controlled, four-arm trial aimed to compare the pharmacokinetics, safety and immunogenicity of HLX11 with US-, EU- and China-sourced reference pertuzumab administrated intravenously in healthy Chinese male subjects. The primary objective of this study is to compare the pharmacokinetics between HLX11 and the three different sourced reference drugs head-to-head. The secondary objectives are to evaluate the safety, tolerability and immunogenicity of HLX11 and the reference drug and further describe their pharmacokinetic profiles. Results from this phase 1 study will provide reference for dosing scheme in the following clinical studies of HLX11.

Up to now, Henlius has a well-established product pipeline in the area of anti-HER2 treatment. Recently, the trastuzumab biosimilar ???^?(HLX02, EU brand name: Zercepac^?), independently developed and manufactured by Henlius, has become the first domestic trastuzumab biosimilar approved in the EU and in China, providing a new standard treatment option for Chinese and European HER2 positive breast and gastric cancer patients. In addition, Henlius is also developing its innovative humanized anti-HER2 IgG1 monoclonal antibody HLX22, which has the potential to further improve treatment outcomes for HER2 positive breast cancer and gastric cancer patients. In the future, HLX11 can also be combined with ???^??or HLX22, which will strengthen Henlius strategy of Global plus Combo. With the accumulated results and experience from extensive anti-HER2 researches, the Company has also built a solid foundation for the discovery and development of anti-HER2 bispecific/multi-target antibodies. In the future, Henlius will keep on innovating and strive for breakthroughs in the anti-HER2 area to bring more affordable and quality biologics to patients around the globe.