trastuzumab + capecitabine or lapatinib + capecitabine

This entry refers to two alternative combination regimens used in the treatment of HER2-positive breast cancer, particularly in advanced or metastatic settings. The first regimen is trastuzumab plus capecitabine, and the second is lapatinib plus capecitabine. - **Trastuzumab** is a monoclonal antibody that targets the human epidermal growth factor receptor 2 (HER2), inhibiting its signaling and leading to decreased proliferation of HER2-overexpressing tumor cells. - **Lapatinib** is a small molecule tyrosine kinase inhibitor that blocks both HER2 and epidermal growth factor receptor (EGFR) pathways, interfering with cell growth and survival signals. - **Capecitabine** is an oral prodrug of fluorouracil (5-FU), a chemotherapy agent that inhibits DNA synthesis by interfering with thymidylate synthase activity. These combinations are primarily indicated for patients with HER2-positive metastatic breast cancer who have previously received other anti-HER2 therapies such as trastuzumab, taxanes, or anthracyclines.