Abstract
Human epithelial growth factor receptor 2-positive (HER2(+)) breast cancer is easy to relapse and metastasize in the early stage, and usually has more aggressive clinical behavior and worse patient survival outcomes as compared with estrogen receptor-positive (ER(+)), HER2-negative (HER2(-)) breast cancer. The HER2(+) breast cancer has been significantly enhanced by trastuzumab and other multiple novel HER2 anti-tumor drugs. The dual combination regimen of trastuzumab + pertuzumab has been established as the standard first-line therapy for advanced HER2(+) patients, and pyrotinib with capecitabine is the preferred second-line treatment in Chinese patients. However, no third- or later-line regimens are currently recommended, and thus, the treatment needs of these patients remain unmet. Margetuximab is a human/mouse chimeric anti-HER2 immunoglobulin G1 (IgG1) monoclonal antibody (mAb) based on the murine precursor of trastuzumab, has shown greater efficacy than trastuzumab in terms of its natural killer (NK) cell-mediated antibody-dependent cell-mediated cytotoxicity (ADCC) effect and may become the preferred solution for HER2(+) metastatic breast cancer (mBC) following progression on second-line therapy with small molecule tyrosine kinase inhibitors (TKIs). This paper explores discussion of therapeutic strategies of anti-HER2 drugs based on Chinese clinical practice, and summarizes the consensus and controversy in the post-anti-HER2 TKIs guideline recommendations, so as to provide certain guidance to HER2(+) mBC patients pretreated with TKIs in the third or later lines.