Table 3.

AMG 181 in vitro pharmacology parameters

AMG 181 assay type	Species	Cell type	Parameter or result
Receptor binding affinity	Human	HuT78 cells expressing α4β7	Kd = 0.9 (0.2–2.3)a pM
Receptor binding specificity	Human	HEK 293 T cellsb	Specific binding to α4β7
Binding to primary T cells	Human	CD4+CD45RA-memory T cells	EC50 = 4.0 ng·mL−1 (26 pM)
	Cynomolgus monkey	CD4+CD28+CD95+ CM T cells	EC50 = 2.6 ng·mL−1 (17 pM)
Blocking of α4β7:MAdCAM-1 binding	Human	CD4+CD45RA-memory T cells	IC50 = 6.4 ng·mL−1 (42 pM)
	Cynomolgus monkey	CD4+CD28+CD95+ CM T cells	IC50 = 4.5 ng·mL−1 (30 pM)
Blocking of T cell adhesionc	Human	HuT78 cells	IC50 = 1.5 ng·mL−1 (10 pM)
	Human	Purified T cells	IC50 = 12.0 ng·mL−1 (80 pM)
	Cynomolgus monkey	Purified T cells	IC50 = 12.6 ng·mL−1 (84 pM)

^aOptimal K_d (95% confidence interval range).

^bTransiently co-transfected with expression vectors for α₄β₇, α₄β₁ or α_Eβ₇ subunits.

^cα₄β₇ : MAdCAM-1-mediated T cell adhesion.