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

RATIONALE: Drugs used in chemotherapy, such as capecitabine and vinorelbine, work in 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. Giving capecitabine and vinorelbine together with trastuzumab may kill more tumor cells. PURPOSE: This phase II trial is studying how well giving capecitabine and vinorelbine together with trastuzumab works in treating patients who have metastatic breast cancer.