Inclusion Criteria:

- Histologically confirmed diagnosis of breast cancer documented by cytology or biopsy

- Evidence of metastatic breast cancer with a minimum of one lesion per RECIST criteria

- Receiving a chemotherapy regimen including one of the following: anthracycline,
taxane, gemcitabine or vinorelbine

- Planned treatment with the same chemotherapy regimen for a minimum of 9 weeks after
Day 1 of study drug administration

- Hemoglobin value between ≥ 6.5 to < 11.0 g/dL

- Life expectancy of ≥ 6 months

Exclusion Criteria:

- Prior radiation therapy to > 20% of the whole skeleton

- > 5 prior chemotherapy treatment regimens for metastatic breast cancer

- Untreated CNS metastases (exception: CNS metastases treated with whole brain
radiotherapy > 6 months prior to randomization)

- Uncontrolled hypertension

- History of anemia as a result of inherited hemoglobinopathy

- History of autoimmune or hereditary hemolysis or gastrointestinal bleeding

- Pregnant or lactating