Trastuzumab and Interleukin-2 in Treating Patients With Metastatic Breast Cancer

Inclusion Criteria: Histologically or cytologically confirmed breast cancer Primary and/or metastatic disease HER2 overexpression 3+ by immunohistochemistry (IHC) or fluorescence in situ hybridization (FISH) Tumors with HER2 2+ overexpression by IHC allowed if confirmed by FISH Progressive disease during or within 12 months of receiving prior regimen containing trastuzumab (Herceptin) Unidimensionally measurable disease At least 20 mm by conventional techniques OR at least 10 mm by spiral CT scan The following are not considered measurable: Bone metastases Pleural or peritoneal effusion Ascites Leptomeningeal disease Lymphangitic disease Inflammatory breast cancer Cystic lesions CNS lesions CNS metastases allowed if all of the following conditions are met: Asymptomatic At least 3 months since prior surgery and/or cranial irradiation At least 3 weeks since prior steroids Hormone receptor status: Not specified Male or female Performance status - ECOG 0-2 Granulocyte count at least 1,000/mm^3 Platelet count at least 100,000/mm^3 Bilirubin no greater than 1.5 times upper limit of normal (ULN) SGOT and SGPT no greater than 2 times ULN (5 times ULN for liver metastases) Alkaline phosphatase no greater than 2 times ULN (5 times ULN for liver metastases) Creatinine no greater than 1.5 times ULN LVEF at least lower limit of normal by MUGA or echocardiogram No congestive heart failure or active ischemic heart disease Not pregnant or nursing Negative pregnancy test Fertile patients must use effective contraception No psychiatric illness, medical condition, or uncontrolled infection that would preclude study No underlying immunodeficiency (e.g., HIV or autoimmune disease) No other prior malignancy within the past 5 years except nonmelanoma skin cancer or carcinoma in situ of the cervix See Disease Characteristics Prior cumulative doxorubicin dose no greater than 360 mg/m^2 At least 3 weeks since prior chemotherapy No more than 2 prior chemotherapy regimens for metastatic disease No concurrent chemotherapy See Disease Characteristics At least 3 weeks since prior endocrine therapy No concurrent corticosteroids or dexamethasone Concurrent hormones allowed for conditions unrelated to disease (e.g., insulin for diabetes) See Disease Characteristics At least 3 weeks since prior radiotherapy No prior radiotherapy to study lesion, unless evidence of disease progression No concurrent palliative radiotherapy See Disease Characteristics At least 4 weeks since prior major surgery No concurrent immunosuppressive drugs