Spebrutinib besylate (AVL-292 benzenesulfonate; CC-292 besylate) is a potent inhibitor of Btk kinase activity (IC50<0.5 nM, Kinact/Ki=7.69×104 M-1s-1s) in biochemical assays. IC50: <0.5 nM (Btk)[1]
Spebrutinib (CC-292) is a covalent, highly selective, orally active inhibitor of Btk with IC50 value of 0.5 nM. Spebrutinib also less potently inhibits Yes, c-Src, Brk, Lyn, and Fyn with IC50s of 723 nM, 1.729 μM, 2.43 μM, 4.4 μM, and 7.15 μM, rspectively. Extensive analysis has revealed that the EC50 of Btk occupancy from a Spebrutinib dose-response in Ramos cells (EC50=6 nM) correlated directly with the cellular EC50 of Btk kinase inhibition with Spebrutinib (EC50=8 nM). Furthermore, the concentration at which Spebrutinib inhibits 90% of Btk activity in Ramos cells is 35 nM while the concentration of Spebrutinib required for 90% occupancy of Btk is 39 nM[1].
[1]. Evans EK, et al. Inhibition of Btk with CC-292 provides early pharmacodynamic assessment of activity in mice and humans. J Pharmacol Exp Ther. 2013 Aug;346(2):219-28.