Primary

Inclusion Criteria:

- Female

- At least 18 years of age

- Histologically or cytologically confirmed adenocarcinoma of the breast

- Stage IV disease

- HER2 status negative

- Measurable disease (revised RECIST; Version 1.1)

- Eastern Cooperative Oncology Group performance status 0 or 1

- Life expectancy of at least 3 months

- Chemotherapy naïve or 1 prior chemotherapy regimen in the adjuvant setting (Prior
taxane-based adjuvant therapy allowed provided patient had a disease-free interval of
at least 12 months after completing this adjuvant therapy)

- Prior hormonal therapy, aromatase inhibitor therapy, and immunotherapy allowed

- Prior radiotherapy in the adjuvant setting allowed provided that less than 25% of the
bone marrow had been irradiated

- Adequate bone marrow, hepatic, and renal function, as specified in the protocol

- At least 4 weeks and recovery from effects of prior surgery, hormonal therapy,
aromatase inhibitor therapy, immunotherapy, radiotherapy, or other therapy with an
approved or investigational agent

- Ability to swallow an oral solid-dosage form of medication

Primary Exclusion Criteria:

- Known metastasis to the central nervous system

- History of other malignancy within the last 5 years other than curatively treated
basal and squamous cell carcinoma of the skin or carcinoma of the cervix in situ

- Significant medical disease other than Stage IV breast cancer

- Presence of neuropathy > Grade 1 (NCI CTC, Version 4.0)

- History of hypersensitivity to a taxane

- Need to continue any regularly-taken medication that is a potent inhibitor or inducer
of the CYP3A pathway or P-glycoprotein activity