Inclusion Criteria

DISEASE CHARACTERISTICS:

- Histologically or cytologically confirmed metastatic breast cancer

- Measurable disease

- Hormone receptor status:

- Not specified

PATIENT CHARACTERISTICS:

Age:

- 18 and over

Sex:

- Female

Menopausal status:

- Not specified

Performance status:

- Karnofsky 60-100%

Life expectancy:

- At least 3 months

Hematopoietic:

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

- Hemoglobin at least 9 g/dL

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

- No impaired bone marrow function

Hepatic:

- Bilirubin no greater than 2 mg/dL

- AST and ALT no greater than 2 times upper limit of normal (ULN)

- Alkaline phosphatase no greater than 2 times ULN (unless attributed to tumor)

- No impaired hepatic function

Renal:

- Creatinine no greater than 2.5 mg/dL OR

- Creatinine clearance at least 60 mL/min

- No impaired renal function

Cardiovascular:

- No prior cardiac disease within the past 5 years OR

- LVEF at least 50%

Other:

- No prior uncontrolled seizures

- No uncontrolled systemic infection

- No anthracycline resistance

- No other malignancy within the past 5 years except curatively treated basal cell or
squamous cell skin cancer or carcinoma in situ of the cervix

- Not pregnant or nursing

- Negative pregnancy test

- Fertile patients must use effective contraception

PRIOR CONCURRENT THERAPY:

Biologic therapy:

- No prior trastuzumab (Herceptin)

Chemotherapy:

- Prior adjuvant therapy with anthracycline of no more than 320 mg/m^2 allowed

Endocrine therapy:

- Not specified

Radiotherapy:

- No prior radiotherapy to more than 1/3 of hematopoietic sites

Surgery:

- Not specified

Other:

- At least 30 days since prior investigational medications and recovered

- No more than 1 prior treatment regimen for metastatic disease