Inclusion Criteria

DISEASE CHARACTERISTICS:

- Histologically confirmed breast cancer

- Metastatic (stage IV) disease

- Measurable disease by RECIST criteria

- Irradiated lesions are not considered measurable disease

- CNS metastases allowed if disease is stable (no evidence of progression) ≥ 3 months
after local therapy

- No lesions identifiable only by PET scan

- HER2 nonoverexpressing disease by IHC (0 or 1) or non-gene amplified by FISH

- HER2 2+ by IHC allowed

- Hormone receptor status:

- Estrogen receptor-negative and progesterone receptor-negative tumor

PATIENT CHARACTERISTICS:

- ECOG performance status 0-2

- Life expectancy ≥ 6 months

- ANC ≥ 1,500/mm³

- Platelet count ≥ 100,000/mm³

- Creatinine clearance ≥ 50 mL/min

- ALT and AST ≤ 2.5 times upper limit of normal (ULN) (≤ 5 times ULN in case of liver
metastases)

- Bilirubin ≤ 1.5 mg/dL

- Not pregnant or nursing

- Negative pregnancy test

- Fertile patients must use effective contraception

- No significant history of uncontrolled cardiac disease including, but not limited to,
any of the following:

- Uncontrolled hypertension

- Unstable angina

- Recent myocardial infarction (within the past 6 months)

- Uncontrolled congestive heart failure

- Cardiomyopathy that is either symptomatic or asymptomatic but with decreased
ejection fraction < 45%

- No history of severe infusion reaction to monoclonal antibody treatment

- No uncontrolled infection

- No major medical condition (i.e., uncontrolled pulmonary, renal, or hepatic
dysfunction) that may affect study participation

- No other significant comorbid condition that may compromise effective and safe
participation in the study

PRIOR CONCURRENT THERAPY:

- See Disease Characteristics

- At least 3 weeks since prior chemotherapy

- At least 2 weeks since prior radiation therapy

- No more than 3 prior chemotherapy regimens either in the adjuvant or metastatic
setting

- Sequential regimens (e.g., anthracycline-paclitaxel) are considered 1 regimen

- No prior therapy that specifically and directly targets the EGFR pathway with
therapeutic intent

- No prior platinum agent for metastatic disease

- Prior platinum agents in the adjuvant setting allowed provided there was a
disease-free interval that lasted for ≥ 12 months prior to relapse

- Concurrent bisphosphonates allowed

- Bone lesions may not be used to measure progression or response