Poseltinib, an orally active, selective and irreversible Bruton's tyrosine kinase (BTK) inhibitor (IC50 =1.95 nM), with 0.3, 2.3 and 2.4-fold selectivity for BTK over BMX, TEC and TXK, respectively. Poseltinib can covalently bind to the active site (cysteine 481 residue) of BTK, and reveales potent inhibition of B cell receptor (BCR), Fc receptor (FcR), Toll-like receptor (TLR) mediated signaling[1].
[1]. Kim YY, et al. HM71224, a selective Bruton's tyrosine kinase inhibitor, attenuates the development of murine lupus. Arthritis Res Ther. 2017 Sep 26;19(1):211.