AZD 4604 is a JAK1 inhibitor (IC50 = 0.54 nM). It is selective for JAK1 over JAK2 and JAK3 (IC50s = 686 and >10,000 nM, respectively), as well as tyrosine kinase 2 (TYK2, IC50 = 657 nM). AZD 4604 inhibits IL-4- or IL-13-induced phosphorylation of STAT6 in U937 cells (IC50s = 24 and 34 nM, respectively). In vivo, AZD...