Balixafortide (POL6326) is a potent, selective, well-tolerated peptidic CXCR4 antagonist with an IC50 < 10 nM. Balixafortide shows 1000-fold selective for CXCR4 than a large panel of receptors including CXCR7. Balixafortide blocks β-arrestin recruitment and calcium flux with IC50s < 10 nM. Balixafortide is also a potent hematopoietic stem and progenitor cell (HSPC) mobilizing agent. Anti-cancer effects[1][2].