Eribulin in HER2 Negative Metastatic BrCa

Improvements in outcomes with metastatic breast cancer (MBC) have been observed in the last 30 years, however, overall prognosis remains poor with median survival of 2 to 3 years. Long term complete responses are observed only for a minority of MBC patients (2-5%) and MBC remains an incurable disease for most patients. Eribulin is a chemotherapy approved by the US FDA in November of 2010 to treat patients with MBC who have received at least two prior chemotherapy regimens. In this research study, the investigators are looking to see how well eribulin helps participants with MBC in an earlier-line setting. Eribulin works by interfering with cancer cell division, growth and spread.

Based on positive results in heavily pre-treated MBC patients, eribulin is being studied as first-line or second-line chemotherapy treatment. This is a non-randomized, open label study with participants enrolled in one of two cohorts: Cohort 1. Hormone receptor (HR)-positive/human epidermal growth factor receptor 2 (HER2)-negative (HR+/HER2-) or Cohort 2: Triple negative breast cancer (TNBC) meaning HR-negative/HER2-negative (HR-/HER2-). HR- means progesterone receptor-negative (PR-) and estrogen receptor-negative (ER-). Beyond efficacy as measured primarily by response to treatment, investigators will evaluate safety, tolerability and quality of life. In particular, it is hypothesized that eribulin may have lower rates of neuropathy, a common side effect of many of the major chemotherapeutics with activity in MBC. The investigators will study the effect eribulin has on the nerves through regular questionnaires that ask about any nerve-related symptoms. The investigators also plan to send blood samples to explore if gene markers may indicate increased sensitivity to the nerve effects of eribulin.

Eligibility Criteria:
Inclusion Criteria:

* Histologically or cytologically proven invasive breast cancer, locally recurrent or metastatic, with at least one measureable lesion according to RECIST v1.1
* Hormone receptor positive or hormone receptor negative HER2-negative disease
* Up to one prior line of chemotherapy for advanced disease is allowed (discontinued at least 14 days prior to initiation of protocol therapy)
* Prior bevacizumab in the neo/adjuvant or metastatic setting is acceptable
* No limit on prior lines of endocrine therapy, but must be discontinued at least 7 days prior to initiation of protocol therapy
* Must have completed any prior radiotherapy at least 2 weeks prior to initiation of protocol therapy
* Must have recovered from reversible effects of prior therapies to no more than grade 1 toxicity, with the exception of alopecia
* Agree to use adequate contraception for the duration of study participation

Exclusion Criteria:

* Pregnant or breastfeeding
* Prior treatment with eribulin
* Prior malignancy other than carcinoma in situ of the cervix or nonmelanoma skin cancer unless diagnosed and definitively treated at least 3 years before enrollment in this study
* Clinically significant cardiovascular impairment
* Active brain metastases or unevaluated neurologic symptoms suggestive of brain metastases
* Pulmonary dysfunction requiring the use of oxygen
* Prior organ allograft requiring immunosuppression
* HIV positive on combination antiretroviral therapy
* Pre-existing grade 3 or 4 neuropathy
* Hypersensitivity to halichondrin B or halichondrin B chemical derivative
* Uncontrolled intercurrent illness
* Inability to read in English