CNX-500 is a probe consisting of a covalent Btk inhibitor (CC-292) chemically linked to biotin. CNX-500 retains inhibitory activity against Btk (IC50 of 0.5 nM) and the ability to form a covalent bond with Btk. CNX-500 has low inhibitory effects on kinase epidermal growth factor receptor, and upstream Src-family kinases including Syk and Lyn[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.