IC50: 10.38 ± 1.99 nM for CXCR4 activation as measured by GTP binding CXCR4 is widely expressed in multiple cell types, and involved in neonatal development, hematopoiesis, and lymphocyte trafficking and homing. Additionally CXCR4 is a co-receptor for HIV. Small molecule antagonists of CXCR4 thus have therapeutic potential. AMD3465 is an N-pyridinylmethylene monocyclam CXCR4 antagonist blocking infection of T-tropic, CXCR4-using HIV. In vitro: Using the CCRF-CEM T-cell line expressing CXCR4 previous authors have demonstrated that AMD3465 is an antagonist of SDF-1 ligand binding, and inhibits SDF-1 mediated signaling as shown by inhibition of GTP binding, calcium flux, and inhibition of chemotaxis. AMD3465 does not inhibit chemokine-stimulated calcium flux in cells expressing CXCR3, CCR1, CCR2b, CCR4, CCR5 or CCR7, nor does it inhibit binding of LTB4 to its receptor, BLT1 . In vivo: AMD3465 caused leukocytosis when subcutaneously administered in mice and dogs, with peak mobilization occurring between 0.5 and 1.5 h following subcutaneous dosing in mice and with maximum peak plasma concentration of compound preceding peak mobilization in dogs, demonstrating that AMD3465 has the potential to mobilize hematopoietic stem cells. These data demonstrate the therapeutic potential for the CXCR4 antagonist AMD3465 . Clinical trials: Currenlty no clinical data are available.