TABLE 2

Summary of in vitro Kd, in vitro EC50 for inhibiting T-cell proliferation in mixed lymphopcyte reaction assay, and EC50 for whole blood CD28 RO

Anti-mCD28 dAb-001Anti-hCD28 dAb-001BMS-931699
In Vitro Kd by Biacore (nM)1.2a (mouse, n = 2)b (monkey)0.57 ± 0.43 (human, n = 7)0.41 ± 0.28 (human, n = 5)
In Vitro MLR EC50 (nM)1.4 ± 0.6 (mouse, n = 15)1.8 ± 1.9 (monkey, n = 16)2.6 ± 1.1 (human, n = 70)2.9 ± 1.2 (human, n = 10)
EC50 for CD28 RO (nM)1.4 ± 0.1c (mouse, n = 12)7.6 ± 0.6c (monkey, n = 19)5.1 ± 2.3d (human, n = 3)4.4 ± 0.9d (human, n = 10)
  • a Average of two Kd values (0.41 and 1.9 nM).

  • b The extracellular domain of human and monkey CD28 receptors is identical, thus the Kd value in monkeys is expected to be the same as that in humans.

  • c Estimated from PK/PD modeling of in vivo RO data.

  • d In vitro EC50.