Capecitabine 7/7 Schedule With Neratinib in Patients With Metastatic HER2-Positive Breast Cancer

This is a phase l/II study. The purpose of this study is to test the safety of the study drug neratinib in combination with a standard chemotherapy drug called capecitabine at different doses to find out what effects, if any, it has on people. Capecitabine (Xeloda®) is approved by the Food and Drug Administration (FDA) for advanced breast cancer treatment. Neratinib is an investigational drug, meaning the FDA has not approved the use of this drug for advanced breast cancer. The combination of capecitabine and neratinib has been studied before in another study where capecitabine was administered using the standard dosing schedule. In this study, the investigators want to find out if a different dosing schedule of capecitabine combined with neratinib is safer. This different dosing schedule is experimental, meaning the administration schedule of capecitabine and neratinib is not FDA approved for treatment for HER2 positive advanced breast cancer.