DISEASE CHARACTERISTICS:

• Histologically confirmed HER2-overexpressing metastatic breast carcinoma

• Clinically or radiologically measurable or evaluable disease

  • Bidimensionally or unidimensionally measurable lesions
• No ascitic, pleural, or pericardial effusions, osteoblastic bone metastases, or carcinomatous lymphangitis of the lung as only indicator lesion
• No known clinical brain or meningeal involvement

• Hormone receptor status:

  • Not specified

PATIENT CHARACTERISTICS:

Age:

• 18 to 70

Sex:

• Female

Menopausal status:

• Not specified

Performance status:

• ECOG 0-1 OR
• SAKK 0-1

Life expectancy:

• At least 12 weeks

Hematopoietic:

• Hemoglobin at least 10 g/dL
• Platelet count at least 100,000/mm^3
• Absolute neutrophil count at least 2,000/mm^3

Hepatic:

• Bilirubin normal
• SGOT and/or SGPT no greater than 2 times upper limit of normal (ULN) (3 times ULN if proven liver metastases) OR
• No SGOT and/or SGPT greater than 1.5 times ULN if alkaline phosphatase greater than 2.5 times ULN

Renal:

• Creatinine no greater than 1.25 times ULN

Cardiovascular:

• LVEF normal
• No history of atrial ventricular arrhythmia, congestive heart failure, or angina pectoris, even if medically controlled
• No history of second or third-degree heart blocks
• No uncontrolled hypertension

Other:

• Not pregnant or nursing
• Fertile patients must use effective contraception
• No pre-existing motor or sensory neuropathy grade 2 or greater
• No psychiatric disorder that would preclude informed consent
• No other prior malignancy except curatively treated nonmelanoma skin cancer or carcinoma in situ of the cervix
• No definite contraindications for use of corticosteroids
• No other concurrent serious illness or medical condition

PRIOR CONCURRENT THERAPY:

Biologic therapy:

• Not specified

Chemotherapy:

• Prior adjuvant or neoadjuvant chemotherapy allowed
• No more than 2 prior chemotherapy regimens for metastatic disease
• No prior cumulative dose of doxorubicin greater than 240 mg/m^2
• No prior cumulative dose of epirubicin greater than 360 mg/m^2
• No prior taxanes

Endocrine therapy:

• Prior hormonal therapy as adjuvant treatment or for metastatic disease allowed
• No concurrent corticosteroids unless started more than 6 months prior to study and at low doses (i.e., no greater than 20 mg methylprednisolone or equivalent)

Radiotherapy:

• Not specified

Surgery:

• Not specified

Other:

• No other concurrent anticancer drugs
• No other concurrent experimental drugs

• No concurrent bisphosphonates unless initiated more than 3 months prior to study

  • Chronic use allowed provided bone metastases are not sole indicator lesions