This is a real world study to evaluate the efficacy and safety of inetetamb combined with pyrotinib and vinorelbine as first-line to third-line treatment after trastuzumab progression in HER2-positive metastatic breast cancer.

HER2-positive breast cancers account for 15%-20% of all breast cancers. Despite trastuzumab has significantly improved the survival of patients with HER2-positivie metastatic breast cancer as the first-line standard treatment, the selection of drugs after trastuzumab treatment failure remains difficulty and challenge. Inetetamab, a new antibody to optimize the ADCC effect, has shown great effectiveness in treating HER2-positive metastatic breast cancer, but therapies subsequent to trastuzumab progression are still controversial. Pyrotinib, another second-line HER2 targeted drug, is a typical representative of TKI drugs, which not only has a strong HER2 antagonistic effect but also can synergize with monoclonal antibodies to amplify the ADCC effect. Here, investigators studied the efficacy and safety of inetetamb combined with pyrotinib and vinorelbine as first-line to third-line treatment after trastuzumab progression, so as to provide new ideas for the treatment of patients with HER2-positive metastatic breast cancer.

Inclusion Criteria:

1. Female and 18-80 years old;
2. The patient was diagnosed as HER2-positive breast cancer by histopathology (HER2 positive (IHC +++ or IHC++ but FISH/CISH+ ));
3. All patients have previously received ≤ 2 lines chemotherapy for metastatic breast cancer;
4. Patients received inetetamab combined with pyrotinib and vinorelbine after trastuzumab failure;
5. According to RECIST 1.1, patients with at least one target lesion or simple bone metastasis can be evaluated;
6. ECOG score of physical status was less than 2, and the expected survival time was not less than 3 months;
7. Complete and traceable medical data.

Exclusion Criteria:

1. Incomplete medical data;
2. The investigator believes that the patient is not suitable to enter this study.

HER2-positive metastatic breast cancer patients received inetetamab combined with pyrotinib and vinorelbine after trastuzumab failure