Monoclonal Antibody Therapy in Treating Women With Locally Advanced or Metastatic Breast Cancer Previously Treated With Combination Chemotherapy

DISEASE CHARACTERISTICS: Histologically or cytologically confirmed breast cancer Locally advanced or metastatic disease No inflammatory breast cancer Polymorphic epithelial mucin (PEM) antigen overexpression by immunohistochemistry Previously treated with an anthracycline and a taxane in any combination for breast cancer No more than 2 prior chemotherapy regimens, including adjuvant /neoadjuvant therapy No more than 1 prior regimen for distant metastatic disease Any number of prior hormonal or biologic therapy regimens allowed Measurable disease At least one unidimensionally measurable lesion not previously irradiated The following are not considered measurable lesions: Bone Leptomeningeal disease Ascites Pleural/pericardial effusion Lymphangitis cutis/pulmonis Abdominal masses not confirmed and followed by imaging techniques Cystic lesions No metastases accessible to complete surgical resection No CNS metastasis by CT scan Hormone receptor status: Not specified PATIENT CHARACTERISTICS: Age 18 and over Sex Female Menopausal status Not specified Performance status WHO 0-2 Life expectancy At least 4 months Hematopoietic Hemoglobin at least 10 g/dL Neutrophil count at least 1,500/mm^3 Platelet count at least 100,000/mm^3 Hepatic Bilirubin no greater than 1.5 mg/dL ALT and AST no greater than 2.5 times upper limit of normal (ULN) (less than 5 times ULN if liver metastases are present) Renal Creatinine no greater than 1.5 times ULN OR Creatinine clearance greater than 60 mL/min No hyperuricemia (uric acid at least 1.25 times ULN) No hypercalcemia (calcium at least 11.5 mg/dL [corrected for serum albumin]) Cardiovascular LVEF at least 45% by MUGA or echocardiogram within the past 4 weeks Other Not pregnant or nursing Negative pregnancy test Fertile patients must use effective contraception during and for 3-6 months after study participation No other prior malignancy within the past 5 years except adequately treated nonmelanoma skin cancer or cervical intraepithelial neoplasia No other concurrent uncontrolled comorbid illness that represents unacceptable risk in the opinion of the investigator No legal incapacity PRIOR CONCURRENT THERAPY: Biologic therapy See Disease Characteristics More than 2 weeks since prior growth factors to aid hematologic recovery No other concurrent immunotherapy Chemotherapy See Disease Characteristics More than 4 weeks since prior cytotoxic chemotherapy No concurrent chemotherapy for metastatic breast cancer Endocrine therapy See Disease Characteristics No concurrent endocrine therapy for metastatic breast cancer No concurrent chronic corticosteroid therapy No concurrent high-dose corticosteroids Radiotherapy More than 4 weeks since prior radiotherapy except for palliation No concurrent antitumor radiotherapy except for palliation Surgery More than 4 weeks since prior major surgery Other More than 2 weeks since prior blood transfusions to aid hematologic recovery No participation in any other investigational drug study No other concurrent investigational drugs No other concurrent antitumor therapy