Shanghai, China, May 6, 2024-Shanghai Henlius Biotech, Inc. (2696.HK) announced that the investigational new drug application (IND) for phase 3 international multicenter clinical study of Henlius’ novel anti-HER2 mAb, HLX22, in combination with trastuzumab and chemotherapy for the first-line treatment of HER2-positive advanced gastric cancer has been approved by the United States Food and Drug Administration (FDA). As of now, no similar dual HER2 blockade therapy for the treatment of HER2-positive gastric cancer has received approval for commercialization globally.

Until now, gastric/gastroesophageal junction (G/GEJ) cancer still constitutes a major global health problem. Globally, there were around 1 million cases in 2022 ^[1]. G/GEJ cancer generally carries a poor prognosis since it is often diagnosed at an advanced stage, with a 5-year relative survival rate of only 6% ^[2,3]. The reported rates of HER2 positivity in patients with gastric cancer range from 12% to 23%, and the prognosis for patients with HER2-positive disease used to be even worse than those with HER2-negative disease ^-2. Currently, for patients with HER2-positive locally advanced/metastatic G/GEJ cancer, the current standard first-line treatment is trastuzumab plus chemotherapy. Immunotherapies are recommended to be added for tumours with PD-L1 expression levels by CPS (Combined Positive Score) of greater than 1. However, the effectiveness and prognosis for these treatments need to be further improved ^[5].

HLX22 is an innovative anti-HER2 mAb that was introduced from AbClon, Inc. and further researched and developed by Henlius. HLX22 can bind to HER2 subdomain IV at a different binding site from trastuzumab, which allows the simultaneous binding of HLX22 and trastuzumab to HER2. Pre-clinical studies have showed that the combination therapy of HLX22 and trastuzumab inhibits the cell proliferation induced by epidermal growth factor (EGF) and Histidine-Rich Glycoprotein 1 (HRG1) and enhance the antitumor activity in vitro and in vivo. The phase 1 clinical trial of HLX22 demonstrates that HLX22 is well tolerated and has good safety profiles. In January 2024, results from the phase 2 study of HLX22 combined with HANQUYOU (trastuzumab for injection, HLX02, trade name in Europe: Zercepac^®) and chemotherapy for the first-line treatment of HER2-positive G/GEJ cancer was first released at the 2024 ASCO Gastrointestinal Cancers Symposium (ASCO GI), which showed that adding HLX22 to HLX02 (trastuzumab for injection) + XELOX improved survival and antitumor response in patients with HER2-positive G/GEJ cancer in the first-line setting, with a manageable safety profile ^[7].

Moving forward, the company will continue to uphold a patient-centric approach, focus on unmet medical needs, and actively explore the optimization of combination therapies for HER2-positive cancer. This includes advancing clinical trials and registrations worldwide for HLX22 to bring hope to more patients around the world.

【Reference】

[1] Bray F, Laversanne M, Sung H, et al. CA Cancer J Clin. 2024: 1-35.

[2] Ajani JA. et al. J Natl Compr Canc Netw 2022;20(2):167-92.

[3] Alsina M. et al. Nat Rev Gastroenterol Hepatol 2023;20(3):155-70.

[4] Gravalos C. et al. Ann Oncol 2008;19(9):1523-9.

[5] NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines^®) for Gastric Cancer V.1.2024

[6] Zhu X, Ding Y, Wang Q, Yang G, Zhou L, Wang Q. HLX22, an anti-HER-2 monoclonal antibody, in patients with advanced solid tumors overexpressing human epidermal growth factor receptor 2: an open-label, dose-escalation, phase 1 trial. Invest New Drugs. 2023;41(3):473-482. doi:10.1007/s10637-023-01338-7

[7] Jin Li et al., HLX22 plus HLX02 and XELOX for first-line treatment of HER2-positive locally advanced or metastatic gastric/gastroesophageal junction cancer: A randomized, double-blind, multicenter phase 2 study.. JCO 42, 354-354(2024).DOI:10.1200/JCO.2024.42.3_suppl.354