Inclusion Criteria

DISEASE CHARACTERISTICS:

- Histologically confirmed metastatic or recurrent breast carcinoma

- Unresectable disease

- Previously treated with no more than 2 chemotherapy regimens for metastatic
disease OR

- Recurrent within 6 months of adjuvant chemotherapy

- Must have one of the following:

- Measurable disease

- Positive bone scan and elevation of serum tumor marker for adenocarcinoma

- Serum levels must have increased over 2 consecutive measurements and exceed
at least 2 times upper limit of normal

- Lewis-y antigen expression documented by immunohistochemistry

- No brain metastases that are uncontrolled or require active treatment (including
steroids)

- Hormone receptor status:

- Not specified

PATIENT CHARACTERISTICS:

Age:

- 18 and over

Sex:

- Female

Menopausal status:

- Not specified

Performance status:

- ECOG 0-2

Life expectancy:

- At least 3 months

Hematopoietic:

- Hemoglobin at least 10 g/dL

- Absolute neutrophil count at least 1,500/mm^3

- Platelet count at least 100,000/mm^3

- No bleeding diathesis

Hepatic:

- Bilirubin no greater than 1.5 mg/dL

- SGOT no greater than 2.5 times normal

- Alkaline phosphatase no greater than 2.5 times normal (unless documented bony
metastasis present)

- Amylase/lipase less than 1.5 times normal

- Hepatitis B and C negative

- No hepatic failure

Renal:

- Creatinine no greater than 1.5 times upper limit of normal

- No renal failure

Cardiovascular:

- LVEF greater than 50% by echocardiogram or MUGA scan

- No congestive heart failure

Other:

- HIV negative

- No antibody present that detects monoclonal antibody BR96 in serum

- No peripheral neuropathy grade 2 or greater

- No dementia or altered mental status

- No other serious underlying medical condition that would preclude study participation

- No prior allergic reactions to recombinant human or murine proteins

- No uncontrolled peptic ulcer disease

- No active viral, bacterial, or systemic fungal infections

- No other primary malignancy except nonmelanoma skin cancer or carcinoma in situ of
the cervix

- No serious nonmalignant disease

- Not pregnant or nursing

- Negative pregnancy test

- Fertile patients must use effective contraception

PRIOR CONCURRENT THERAPY:

Biologic therapy:

- At least 8 weeks since prior therapeutic or diagnostic murine/humanized/human
chimeric antibodies

Chemotherapy:

- See Disease Characteristics

- At least 4 weeks since prior chemotherapy (6 weeks for nitrosoureas, carboplatin,
mitomycin, or anthracyclines)

- No prior cumulative anthracycline of 300 mg/m2 or more

- No concurrent antineoplastic agents

Endocrine therapy:

- See Disease Characteristics

- At least 4 weeks since prior hormonal therapy

- No concurrent hormonal therapy except estrogen replacement

Radiotherapy:

- At least 4 weeks since prior radiotherapy

Surgery:

- See Disease Characteristics

Other:

- No other concurrent experimental agents

- No concurrent immunosuppressive medications