Tofacitinib is an oral, small molecule JAK inhibitor for the treatment of ulcerative colitis (UC). Safety and efficacy of tofacitinib were evaluated in 2 Phase 3 induction studies (OCTAVE Induction 1 & 2, NCT01465763 & NCT01458951), a 52-week (wk), Phase 3 maintenance study (OCTAVE Sustain, NCT01458574),1 and an ongoing open-label, long-term extension study (NCT01470612).2 In these trials, endpoint definitions were based on the conventional Mayo score comprising 4 subscores (stool frequency, rectal bleeding, endoscopic findings, Physician Global Assessment [PGA]).