...preliminary phase 1 activity of the CXCR4 antagonist, balixafortide, in combination with eribulin chemotherapy in...histologically confirmed HER2-negative metastatic breast cancer, evidence of tumour cell CXCR4 expression...Objective responses (all partial responses) were observed in 16 (30%; 95% CI 18-44) of 54 patients who were evaluable for antitumour activity.