The primary objective of this open-label, safety study of recombinant humanized anti-p185 HER2 monoclonal antibody (rhuMAb HER2 ) in patients with HER2 overexpression who have relapsed following two cytotoxic chemotherapy regimens for metastatic breast cancer is to provide expanded access to this treatment due to the limited supply. The secondary objectives are to determine overall response rates and overall survival.