Inclusion Criteria:

- Histologically or cytologically confirmed HER2-negative metastatic (stage IV) breast
cancer.

- Measurable or non-measurable, but radiologically evaluable, disease according to
RECIST 1.1 criteria.

- Female aged 18 years or older.

- Life expectancy > 3 months.

- Eastern Cooperative Oncology Group (ECOG) performance status 0 or 1.

- Either ER-positive or ER-negative disease. Patients with ER-positive disease must be
endocrine resistant, defined as having failed at least one prior endocrine therapy
for breast cancer, or must be candidates for first-line chemotherapy.

- If previously treated with a taxane or anthracycline in the neoadjuvant or adjuvant
setting, the period from end of treatment to disease recurrence must have been > 12
months (> 365 days).

- Radiation therapy, if given and regardless of site, must be completed at least 2
weeks prior to randomization.

- Normal hematologic status.

- Normal renal function.

- Normal liver function.

- Normal cardiac function.

- Women of childbearing potential: documented negative pregnancy test within 2 weeks
prior to randomization, and acceptable birth control during the duration of the trial
therapy and for a period of 6 months following the last administration of study drug.

- Written Informed Consent (IC) must be signed and dated by the patient and the
Investigator prior to randomization.

- Completed baseline Quality of Life Form.

- The patient has been informed of and agrees to data transfer and handling, in
accordance with national data protection guidelines.

- Availability of an formalin fixed paraffin embedded (FFPE) block from the primary
tumor (breast lesion) for submission to central pathology review and for
translational research.

- Written consent to pathology material submission, signed and dated by the patient and
the Investigator prior to randomization.

Exclusion Criteria:

- Any prior chemotherapy for metastatic breast cancer.

- Presence of central nervous system (CNS) metastasis.

- Peripheral neuropathy grade 2 or higher (CTCAE version 4).

- Significant uncontrolled cardiac disease (i.e. unstable angina, recent myocardial
infarction within prior 6 months), patients classified as having a New York Heart
Association (NYHA) class III or IV congestive heart failure.

- Pregnant or lactating.

- Prior history of non-breast malignancy (except for adequately controlled basal cell
carcinoma of the skin, carcinoma in situ of the cervix, in situ carcinoma of the
bladder).

- Any concurrent condition which in the Investigator's opinion makes it inappropriate
for the patient to participate in the trial or which would jeopardize compliance with
the protocol.

- Contraindications or known hypersensitivity to the study medication or excipients.

- The use of any anti-cancer investigational agents within 30 days prior to expected
start of trial treatment.

- Inability or unwillingness to abide by the study protocol or cooperate fully with the
Investigator.