Capecitabine, Paclitaxel, and Trastuzumab in Treating Patients With Metastatic Breast Cancer

RATIONALE: Drugs used in chemotherapy use different ways to stop tumor cells from dividing so they stop growing or die. Monoclonal antibodies such as trastuzumab can locate tumor cells and either kill them or deliver tumor-killing substances to them without harming normal cells. Combining chemotherapy with monoclonal antibody therapy may kill more tumor cells. PURPOSE: Phase I/II trial to study the effectiveness of combining capecitabine, paclitaxel, and trastuzumab in treating patients who have metastatic breast cancer.