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