Clinical Trial of TQB2102 for Injection Versus Trastuzumab Emtansine for Injection in HER2-positive Advanced Breast Cancer

Inclusion Criteria: * The subjects voluntarily participated in this study, signed the informed consent form, and had good compliance; * Age: 18 - 75 years old (at the time of signing the informed consent form); Eastern Cooperative Oncology Group (ECOG )score ≤ 1; Expected survival period exceeds 3 months; * HER2-positive, unresectable, locally advanced or metastatic invasive breast cancer confirmed by histopathological or cytological examination; * According to the 2018 version of the American Society of Clinical Oncology (ASCO)/College of American Pathologists (CAP )HumanEpidermalGrowthFactorReceptor2 (HER2) testing guidelines, HER2 positive is defined as: immunohistochemical result of 3+ or Fluorescence In Situ Hybridization (FISH) dual probe positive; * The hormone receptor (HR) status has been clearly determined: a) According to the 2020 version of the ASCO/CAP guidelines, HR positive includes ER positive and/or PR positive, that is, the proportion of tumor cells with positive staining among all tumor cells is ≥ 1%. * Received anti-HER2 monoclonal antibody and taxane drugs during the recurrence/metastasis stage. * Disease progression occurred during or after the most recent treatment or intolerance. * At least 1 line of treatment has been received in the recurrence/metastasis stage. * According to the Response Evaluation Criteria In Solid Tumors (RECIST) 1.1 standard, at least one measurable lesion exists. Exclusion Criteria: * Excluded are patients with known spinal cord compression or active central nervous system metastases . * Patients with only skin and/or intracranial lesions as target lesions. * Patients with adverse reactions from previous treatments that have not recovered to a CTCAE v5.0 grade score of ≤1. * Patients with poorly controlled blood pressure (systolic blood pressure ≥150 mmHg or diastolic blood pressure ≥100 mmHg). * Patients with major cardiovascular diseases * Patients with a history of interstitial lung disease/pneumonia (non-infectious type) requiring steroid intervention treatment, or currently having interstitial lung disease/pneumonia, or those with suspected interstitial lung disease/pneumonia indicated by screening period imaging and cannot be excluded.