Janus-associated kinases (JAKs) are cytoplasmic tyrosine kinases that are required for activating the signaling of certain cytokines and growth factor receptors. Oclacitinib is an orally bioavailable, broad spectrum JAK inhibitor (IC50s = 10, 18, 99, and 84 nM for JAK1, JAK2, JAK3, and JAK4, respectively). It is specific for JAK isozymes against a large panel of other kinases. Oclacitinib blocks cell-based JAK signaling induced by IL-2, IL-4, IL-6, IL-13, or IL-31 with IC50 values ranging from 36 to 249 nM. Oral oclacitinib is used against atopic dermatitis with pruritus in dogs.
