Exposure–response characterization of tofacitinib efficacy in moderate to severe ulcerative colitis: Results from a dose‐ranging phase 2 trial

Aims Tofacitinib is an oral, small molecule JAK inhibitor being investigated for ulcerative colitis (UC). In a phase 2 dose‐ranging study, tofacitinib demonstrated efficacy vs. placebo as UC induction therapy. In this posthoc analysis, we aimed to compare tofacitinib dose and plasma concentration as predictors of efficacy and identify covariates that determined efficacy in patients with UC.