The purpose of this study is to assess the impact on tumor progression as evaluated by progression-free survival (PFS) of epoetin alfa plus standard supportive care as compared with standard supportive care alone (packed red blood cell (RBC) transfusions), for treating anemia according to label guidance in patients with metastatic breast cancer receiving standard chemotherapy.

Anemia is a common complication of the treatment of metastatic breast cancer and is related to the effects of chemotherapy and to chronic disease itself. This is a randomized, open-label, multicenter, international study to further examine the safety of the study drug used with standard supportive care (i.e., packed RBC transfusions) compared to standard supportive care alone, when used to treat anemia associated with chemotherapy. This study will be done in subjects with metastatic breast cancer who are being or will be treated with first-line chemotherapy with standard dose schedules of taxane monotherapy, or a taxane plus trastuzumab, or an anthracycline plus either a taxane or cyclophosphamide. The study hypothesis is that epoetin alfa, when used as supportive anemia care, does not increase the risk of tumor progression or death. The study treatment will be compared to the control treatment by comparing progression-free survival, i.e., the number of months from the date a patient is randomized into the trial to the date of the first documented disease progression or death. In addition to their chemotherapy, half of the subjects will be assigned to receive study drug (epoetin alfa) and half of the subjects will be assigned to standard supportive care for anemia. Subjects treated with the study drug will receive standard supportive care (packed RBC transfusions) plus 40,000 IU epoetin alfa given subcutaneously once a week until 4 weeks after the last cycle of chemotherapy or until disease progression, whichever comes first.The hypothesis is to test that epoetin alfa, when used as supportive anemia care, is non-inferior to control (standard supportive care alone), as measured by progression free survival (PFS). Patients treated with the study drug will receive standard supportive care (packed red blood cells (RBC) transfusions) plus 40,000 IU epoetin alfa given subcutaneously once a week until 4 weeks after the last cycle of chemotherapy or until disease progression, whichever comes first. Dose adjustments (dose escalation, dose reduction, dose interruption, and dose resumption) of epoetin alfa will be based on hemoglobin (Hb) and confirm to prescribing information.

Inclusion Criteria:

• Histologically confirmed (e.g., slide of tissue) breast cancer
• HER2/NEU positive or negative
• Clinical evidence of metastasis (e.g., biopsy) with at least 1 measurable metastatic (M1) lesion prior to starting the current chemotherapy
• Received 1st and 2nd line chemotherapy
• Hemoglobin (Hb) <= 11g/dL at the time of randomization
• planned to receive at least 2 more cycles of chemotherapy
• Life expectancy > 6 months
• Eastern Cooperative Oncology Group score 0 or 1
• At least 18 years old using effective birth control or surgically sterile or postmenopausal for 1 year

Exclusion Criteria:

• Active second cancer
• no recent history of clinically relevant thrombovascular event
• Current treatment with anticoagulants
• Brain metastasis or CNS involvement
• Anemia secondary to another cause
• Recent (within prior 1 months) use of an ESA
• Patient pregnant or breast feeding
• Progressive disease during adjuvant/neoadjuvant chemotherapy
• Rapidly progressive or life-threatening metastatic disease
• Concomitant endocrine therapy
• Patient in whom the only site of metastasis was local and was successfully treated surgically.