Evaluation of a New Agent for Treatment of Advanced Stage Breast Cancer

Inclusion Criteria: * Metastatic breast cancer (meaning the cancer has spread beyond its original location) * At least one measurable lesion by CT or MRI * Progression of disease following previous therapy for breast cancer * Have received previous treatment with anthracyclines (e.g. doxorubicin\[Adriamycin or Doxil\] or epirubicin \[Ellence\]), taxanes (paclitaxel \[Taxol or Abraxane\] or docetaxel \[taxotere\]) for your breast cancer * Not be pregnant * Additional criteria to be determined at screening visit. Exclusion Criteria: * More than 3 previous chemotherapy regimens * More than one treatment with non cytotoxic agents for breast cancer therapy (e.g. herceptin \[trastuzumab\] or Avastin \[bevacizumab) * Prior treatment with epothilones (e.g. Ixabepilone) * Symptomatic brain metastases * Additional criteria to be determined at screening visit