Inclusion Criteria

DISEASE CHARACTERISTICS: Histologically confirmed metastatic or recurrent breast cancer
(not confined to breast) One prior induction chemotherapy regimen for recurrent or
metastatic disease (4 weeks of treatment for 4-6 courses) resulting in stable disease,
partial response, or complete response Pleural or peritoneal effusion palliated by
induction chemotherapy allowed No uncontrolled brain metastases Previously treated brain
metastases allowed if: No evidence of progression for at least 3 months following
radiotherapy and/or surgical treatment AND At least 30 days since dexamethasone or other
corticosteroids AND Other metastatic site exists No bone marrow or brain as only sites of
metastases No meningeal disease Hormone receptor status Estrogen receptor status known

PATIENT CHARACTERISTICS: Age: 18 and over Performance status: ECOG 0-1 Menopausal status:
Not specified Life expectancy: Not specified Hematopoietic: WBC at least 3,000/mm3
Absolute neutrophil count at least 1,500/mm3 Hemoglobin at least 9 g/dL (transfusion or
epoetin alfa allowed) Platelet count at least 100,000/mm3 Hepatic: SGOT/SGPT no greater
than 1.5 times upper limit of normal (ULN) Albumin at least 3.0 g/dL Bilirubin no greater
than 1.5 times ULN Renal: Creatinine no greater than 1.5 times ULN Creatinine clearance at
least 60 mL/min Other: No other active malignancy except nonmelanoma skin cancer Not
pregnant or nursing Fertile patients must use effective contraception No inflammatory
bowel disease or active gastric ulcer No prior autoimmune disease or immunodeficiency
syndrome

PRIOR CONCURRENT THERAPY: Biologic therapy: See Chemotherapy No concurrent interleukin-11
Chemotherapy: See Disease Characteristics No concurrent chemotherapy Prior chemotherapy
with bone marrow progenitor support (bone marrow transplant and/or peripheral blood stem
cell support) allowed in adjuvant setting only (not for metastases) Endocrine therapy:
Prior hormone therapy for breast cancer allowed No concurrent hormones allowed except for
non-cancer or cancer treatment related conditions (e.g. insulin for diabetes) No
concurrent dexamethasone or other steroidal antiemetics Radiotherapy: Prior radiotherapy
allowed No concurrent radiotherapy Surgery: Not specified Other: Prior bisphosphonate
therapy allowed if started at least 3 months before study No initiation of bisphosphonate
therapy during study