A Study Of PF-05280014 [Trastuzumab-Pfizer] Or Herceptin® [Trastuzumab-EU] Plus Paclitaxel In HER2 Positive First Line Metastatic Breast Cancer Treatment (REFLECTIONS B327-02)

Inclusion Criteria:

• Histologically confirmed diagnosis of breast cancer.
• Presence of metastatic disease.
• Documentation of HER2 gene amplification or overexpression.
• Available tumor tissue for central review of HER2 status.
• At least 1 measurable lesion as defined by RECIST 1.1.
• Eastern Cooperative Oncology Group status of 0 to 2.
• Left ventricular ejection fraction within institutional range of normal, measured byeither two dimensional echocardiogram or multigated acquisition scan.

Exclusion Criteria:

• Relapse within 1 year of last dose of previous adjuvant (including neoadjuvant)treatment (except endocrine therapy) and within 1 year before randomization.
• Prior systemic therapy for metastatic disease (except endocrine therapy).
• Prior cumulative dose of doxorubicin of >400 mg/m2, epirubicin dose >800 mg/m^2, orthe equivalent dose for other anthracyclines or derivatives (eg, 72 mg/m^2 ofmitoxantrone). If the patient has received more than one anthracycline, then thecumulative dose must not exceed the equivalent of 400 mg/m^2 of doxorubicin.
• Inflammatory breast cancer.
• Active uncontrolled or symptomatic central nervous system metastases.