Tofacitinib, an oral Janus kinase inhibitor, in active ulcerative colitis.

Background: Ulcerative colitis is a chronic inflammatory disease of the colon for which current treatments are not universally effective. One additional treatment may be tofacitinib (CP-690,550), an oral inhibitor of Janus kinases 1, 2, and 3 with in vitro functional specificity for kinases 1 and 3 over kinase 2, which is expected to block signaling involving gamma chain-containing cytokines including interleukins 2, 4, 7, 9, 15, and 21. These cytokines are integral to lymphocyte activation, function, and proliferation.