Introduction: Tofacitinib is an oral, small molecule JAK inhibitor that is being investigated for ulcerative colitis (UC). The efficacy and safety of tofacitinib was demonstrated as induction and maintenance therapy in 3 Phase 3, randomized, placebo-controlled studies (OCTAVE Induction 1, NCT01465763; OCTAVE Induction 2, NCT01458951; OCTAVE Sustain, NCT01458574) in patients (pts) with moderate to severe UC.1 Methods: We present interim safety and efficacy data up to 3 yrs of treatment (as of July 8, 2016) from an ongoing Phase 3, multicenter, open-label, long-term extension study (OLE; NCT01470612) in pts who had completed or demonstrated treatment failure in OCTAVE Sustain, or who were non-responders after completing OCTAVE Induction 1 or 2. Pts in remission at Week 52 of OCTAVE Sustain received tofacitinib 5 mg twice daily (BID); all others received 10 mg BID. At Month 2, all pts underwent endoscopy, and non-responders from induction were mandated to withdraw if no evidence of clinical response was shown. Remission was defined by a Mayo score ≤2 with no individual subscore >1, and rectal bleeding subscore of 0. Binary efficacy endpoints were derived from Mayo score, based on local-read endoscopic subscore. Results: 914 pts (5 mg BID, N=156 [17.1%]; 10 mg BID, N=758 [82.9%]) received ≥1 dose of study drug; 381 pts (41.7%) discontinued. The most frequent AE leading to discontinuation was worsening of UC. Serious and severe AEs occurred in 10.4% and 7.8% of pts, respectively (dose groups combined). The most frequent treatment-emergent AEs by system organ classes (both doses) were ‘infections/infestations' and ‘gastrointestinal disorders', and by preferred term were ‘nasopharyngitis' and ‘worsening of UC'. Serious infections AEs were reported in 4 (2.6%) and 14 (1.8%) pts with 5 and 10 mg BID, respectively. Malignancies excl. NMSC were reported in 9 (1.2%) pts in the 10 mg BID group (no clustering of malignancy type); none were reported in the 5 mg BID group. No new safety risks were identified. Data ‘as observed' for remission and mucosal healing at Months 2, 12, and 24 are shown.Table: Table. Summary of safety and efficacy in the OLE studyConclusion: In pts with moderate to severe UC who remained in the OLE study, no new safety concerns emerged compared with those observed with tofacitinib in rheumatoid arthritis. Efficacy results from this OLE study support sustained efficacy with tofacitinib 5 and 10 mg BID. Funded by Pfizer Inc.