Inclusion Criteria:

- Histologically or cytologically proven diagnosis of metastatic breast adenocarcinoma
that is not amenable to surgery, radiation, or combined modality therapy with
curative intent.

- Must have received prior treatment with an anthracycline and a taxane either
concurrently or sequentially in the adjuvant and/or advanced disease treatment
settings. Patients may have received as many as 2 other chemotherapy regimens in the
advanced disease setting. Patients whose tumors are Her-2-positive must have received
prior trastuzumab therapy. Prior hormonal therapy or immunotherapy in the adjuvant
and/or advanced/metastatic disease settings is permitted. Prior treatment with
surgery, radiotherapy, chemoembolization therapy, or cryotherapy is allowed if these
therapies did not affect the areas of measurable disease.

Exclusion Criteria:

- Prior treatment with >/= 3 regimens of chemotherapy in the metastatic disease setting
beyond those containing anthracyclines and taxanes

- Uncontrolled brain metastases, spinal cord compression, or carcinomatous meningitis,
or new evidence of brain or leptomeningeal disease. Patients should have completed
surgery or radiation therapy for existing brain metastases, should not have
documented increase in size over the previous 3 months and should be asymptomatic