Dose Escalation of POL6326 in Combination With Eribulin in Patients With Metastatic Breast Cancer

Inclusion Criteria:

* Histologically confirmed invasive cancer of the breast.
* Presence of at least one measurable lesion per RECIST 1.1 criteria
* Stage IV disease by AJCC criteria (7th edition).
* HER2 negative (IHC 0,1 or FISH HER2:CEP17 ratio \< 2.0)
* Must have had treatment with at least 2 but no more than 3 previous regimens in the metastatic setting. Previous treatment must have included an anthracycline and taxane in either the adjuvant or metastatic setting.
* At least 21 days from the completion of any previous cytotoxic chemotherapy or biological therapy at time of initiation of POL6326.
* ECOG performance status \< 2

Exclusion Criteria:

* Previously received eribulin.
* Peripheral neuropathy \> Grade 2.
* Receipt of any other investigational agent within the 28 days prior to Day 1.
* Receipt of colony stimulating factor filgrastim, pegfilgrastim, or sargramostim within 14 days prior to Day 1.
* Radiation therapy within the 14 days prior to Day 1.
* Severe concurrent illness or psychiatric illness/social situation that would limit compliance with study requirements.
* History of other malignancy ≤ 5 years previous with the exception of basal cell or squamous cell carcinoma of the skin which were treated with local resection only or carcinoma in situ of the cervix.
* Pregnant or breastfeeding.
* Known HIV positivity on combination antiretroviral therapy; these patients are at increased risk of lethal infections when treated with marrow-suppressive therapy