P505-15 hydrochloride

P505-15 is a potent, cell-permeable, highly selective, small molecule SYK inhibitor (IC₅₀ = 1 nM) with anti-SYK activity that is at least 80-fold greater than its affinity for other kinases.  P505-15 blocks B cell receptor-mediated cell signaling and activation in whole blood (IC₅₀s = 0.27 and 0.28 µM, respectively), as well as Fcɛ receptor 1-mediated basophil degranulation (IC₅₀ = 0.15 µM).