International, phase 3 trial: Balixafortide (a CXCR4 antagonist) + eribulin versus eribulin alone in patients with HER2 negative, locally recurrent or metastatic breast cancer (FORTRESS) international, phase 3 trial: Balixafortide (a CXCR4 antagonist) + eribulin versus eribulin alone in patients with HER2 negative, locally recurrent or metastatic breast cancer (FORTRESS)