A Study of Patients With HER2 Gene Amplified Metastatic Breast Cancer Treated With First Line Herceptin and a Taxane

Inclusion Criteria: * Signed informed consent * Available tissue for central laboratory evaluation of HER2 status * Histologically confirmed, measurable or nonmeasurable but evaluable, HER2 positive metastatic breast cancer (HER2 positive is defined as 3+ staining by IHC or gene amplification by FISH, determined by the local or central laboratory) * Life expectancy \>6 months * Female, age \>=18 years * ECOG performance status of 0, 1, or 2 * Adequate bone marrow function as indicated by the following: \*ANC \>1500/uL, \*Platelet count \>=100,000/uL * Adequate renal function, as indicated by creatinine \<=1.5× upper limit of normal (ULN) * Adequate liver function, as indicated by bilirubin \<=1.5× ULN and AST or ALT \<2× ULN unless related to primary disease * Use of an adequate means of birth control (women of childbearing potential) Exclusion Criteria: * Initiation of Herceptin \>=4 weeks after beginning taxane chemotherapy * Prior chemotherapy for metastatic disease * Prior cumulative anthracycline dose of \>360 mg/m2 * History of significant cardiac disease or uncontrolled arrhythmias * Ejection fraction of \<50% or below the lower limit of normal * Active infection * Symptomatic or untreated brain metastases * Pregnancy or lactation * Concomitant malignancies or previous malignancies within the last 5 years, with the exception of adequately treated basal or squamous cell carcinoma of the skin or carcinoma in situ of the cervix * Symptomatic intrinsic lung disease or extensive tumor involvement of the lungs, resulting in dyspnea at rest * Hypersensitivity to study medications * Major organ failure or systemic disease precluding the safe administration of study medications