Efficacy and Safety of Disitamab Vedotin Plus Pyrotinib or Naratinib in HER2-positive Breast Cancer Patients With Brain Metastasis

Basis: Brain metastasis is very common in breast cancer, and HER2 positivity is a risk factor for high incidence of brain metastasis, with approximately 50% of HER2+ MBC cases experiencing brain metastasis. The reason for this is that as the efficacy of HER2-targeted therapy improves, the survival of these patients significantly extends, leading to an increase in the occurrence rate of brain metastasis events in the late stage of MBC. In the systemic treatment of HER2+ breast cancer brain metastasis, various HER2-targeted drugs have been explored, but none have achieved satisfactory therapeutic effects. Therefore, it is imperative to explore new treatment options. ADC drugs have shown some efficacy in brain metastasis patients, and as a domestically developed ADC drug, trastuzumab vedotin has demonstrated good anti-tumor effects. The treatment model combining trastuzumab vedotin with small molecule TKIs has been rarely reported, so we are attempting to use the treatment model of trastuzumab vedotin combined with pyrotinib or neratinib to explore its efficacy and safety in patients with HER2-positive brain metastasis. Method: The plan is to recruit HER2-positive breast cancer patients with brain metastasis and use the treatment of trastuzumab vedotin combined with pyrotinib or neratinib (specific treatment drugs to be selected during the study). Procedure: All subjects will undergo screening, treatment, and follow-up periods, strictly adhering to relevant GCP regulations during the treatment process. Expectations: Through this study, preliminary efficacy and safety data of trastuzumab vedotin combined with pyrotinib or neratinib treatment will be provided for patients with HER2+ brain metastatic BC.