BAY 61-3606 (hydrochloride)

BAY 61-3606 is an inhibitor of spleen tyrosine kinase (Syk; Ki = 7.5 nM).{31575} It is selective for Syk over Lyn, Fyn, Src, Itk, and BTK (Kis = >4.7 µM for all). BAY 61-3606 inhibits anti-IgE-induced histamine release in isolated human mast cells sensitized with IgE (IC50 = 5.1 nM), as well as reduces anti-IgM-induced proliferation of isolated mouse splenic B cells (IC50 = 58 nM). It sensitizes MCF-7 human breast cancer cells to apoptosis induced by TNF-related apoptosis-inducing ligand (TRAIL) when used at concentrations ranging from 0.31 to 2.5 µM.{31573} BAY 61-3606 inhibits passive cutaneous anaphylaxis in rats (ED50 = 8 mg/kg).{31575} It reduces tumor growth in an MCF-7 mouse xenograft model when administered at a dose of 50 mg/kg alone or in combination with TRAIL.{31573}