Inclusion Criteria

DISEASE CHARACTERISTICS:

- Histologically confirmed breast cancer

- Locally advanced or metastatic disease

- Recurrent or refractory disease

- Histological or cytological confirmation required for recurrence in a solitary
site

- Must have received prior anthracycline and taxane as neoadjuvant, adjuvant, or
metastatic therapy

- Measurable disease*

- At least 1 measurable site of disease, defined as ≥ 1 unidimensionally
measurable lesion ≥ 20 mm by conventional techniques or ≥ 10 mm by spiral CT
scan

- Palpable disease allowed NOTE: *Lesions that have been irradiated in the
advanced setting cannot be included as sites of measurable disease

- No nonmeasurable disease only, including the following:

- Bone lesions

- Leptomeningeal disease

- Ascites

- Pleural or pericardial effusion

- Inflammatory breast disease

- Lymphangitic pulmonary disease

- Abdominal masses that are not confirmed and followed by imaging techniques

- Cystic lesions

- No HER2-positive disease, defined as 3+ by IHC OR positive by FISH or chromogenic in
situ hybridization

- Hormone receptor status not specified

PATIENT CHARACTERISTICS:

- Male or female

- Menopausal status not specified

- ECOG performance status 0-1

- Estimated life expectancy ≥ 12 weeks

- Not pregnant or nursing

- Fertile patients must use effective contraception during and for 3 months after
completion of study therapy

- ANC ≥ 1,500/mm³

- Platelet count ≥ 100,000/mm³

- Hemoglobin ≥ 9 g/dL

- ALT or AST < 2.5 times upper limit of normal (ULN)

- Bilirubin normal

- Alkaline phosphatase ≤ 2.5 times ULN

- Creatinine ≤ 1.25 times ULN OR creatinine clearance > 40 mL/min

- Calcium ≤ 1.2 times ULN

- No concurrent serious medical or psychiatric illness, including any serious active
infection incompatible with the study

- No other primary malignancy except carcinoma in situ of the cervix, adequately
treated nonmelanomatous skin cancer, or any other malignancy previously treated ≥ 5
years ago with no evidence of recurrence

- No peripheral neuropathy ≥ grade 2

PRIOR CONCURRENT THERAPY:

- See Disease Characteristics

- Recovered from prior chemotherapy

- Prior hormonal therapy or immunotherapy allowed

- Antitumoral hormonal therapy must be discontinued prior to study entry

- More than 4 weeks since prior radiotherapy and recovered

- No prior radiotherapy to the whole pelvis or to ≥ 25% of the bone marrow

- No prior gemcitabine hydrochloride, cisplatin, or carboplatin

- No other cytotoxic chemotherapy for 21 days before and for 14 days after completion
of study therapy

- More than 30 days since prior treatment with a drug (not including study drug) that
has not received regulatory approval for any indication at the time of study entry

- Bisphosphonate therapy may not be initiated or discontinued within 4 weeks of study
entry

- No more than 1 prior course of chemotherapy for metastatic disease

- Prior chemotherapy in the adjuvant setting allowed

- Concurrent palliative radiotherapy to existing painful lesions (soft tissue or bone)
allowed

- New bone pain requiring radiotherapy > 4 weeks after first study treatment
considered disease progression

- New pain in a soft tissue lesion without other objective changes may be
irradiated provided ≥ 1 other site of nonirradiated measurable disease exists

- No other concurrent anticancer treatment

- No concurrent tamoxifen citrate, aromatase inhibitors, or progestagens