An antagonist of CXCR4, blocking CXCR4-mediated HIV infection with an IC50 value of 19.3 nM; at 100 μg/ml, inhibits CXCL12-induced phosphorylation of p42/44 MAPK and STAT3; activates CXCR7 (EC50 = 350 nM), resulting in the recruitment of β-arrestin and Erk ½ phosphorylation.