Pivotal Study in HER2 Negative, Locally Recurrent or Metastatic Breast Cancer

Open to people ages 18 years and up

• Histologically confirmed Breast cancer
• Metastatic Breast Cancer currently of stage IV disease or unresectable locoregionally recurrent breast cancer
• refractory to the most recent chemotherapy, documented by progression on or within six (6) months of therapy
• At least 14 days from the completion of any previous cancer therapy
• Adequate organ function
• Life expectancy of 3 months or more
• Willing and able to comply with the protocol and able to understand and willing to sign an informed consent

• Previously treated with eribulin
• Peripheral neuropathy Grade ≥3
• Receipt of prior CXCR4 therapy
• Receipt of colony stimulating factors (CSFs) filgrastim, pegfilgrastim, or sargramostim, or radiation therapy within 14 days prior to study Day 1
• History of allergic reactions attributed to compounds of similar chemical or biologic composition to balixafortide or eribulin or other agents used in the study
• Breast feeding or pregnant
• Patients with congestive heart failure, electrolyte abnormalities, bradyarrhythmias, known congenital long QT syndrome, QT interval corrected with Fridericia's formula (QTcF) ≥470 msec at baseline in the absence of bundle branch block, or currently taking drugs at known risk of prolonging the QT interval or causing torsades de pointes