Oclacitinib maleate (formerly PF-03394197 maleate) is a novel and potent inhibitor of JAK (Janus kinase) family members with IC50 values ranging from 10 to 99 nM and JAK1-dependent cytokines with IC50 ranging from 36 to 249 nM. Oclacitinib did not inhibit a panel of 38 non-JAK kinases and is the most potent at inhibiting JAK1. Oclacitinib also inhibits the function of JAK1-dependent cytokines involved in allergy and inflammation as well as pruritus. Cclacitinib is a targeted therapy that selectively inhibits JAK1-dependent cytokines involved in allergy, inflammation, and pruritus and suggests these are the mechanisms by which oclacitinib effectively controls clinical signs associated with allergic skin disease in dogs.