Comparative study of Infliximab monotherapy vs combined therapy with azathiopurine for inducing and maintaining clinical remission in steroid-dependent or -resistant ulcerative colitis

INTERVENTION: Patients in Infliximab monotherapy receive intravenous infusion of IFX at week 0, 2, and 6, and then every 8 weeks (up to week 54). Patients in the combination therapy of Infliximab and azathiopurine receive intravenous infusion of IFX (at week 0, 2, 6, and then every 8 weeks) and oral azathiopurine (up to week 54). CONDITION: ulcerative colitis PRIMARY OUTCOME: Remission and clinical response rate at week 30 SECONDARY OUTCOME: 1) Remission rate (CAI 0‐4) at week 8, 30, and 54 ; 2) Clinical response (more than 50 percent reduction from baseline in their CAI) at week 8 and 54; 3) Mucosal healing at week 8 and 54; 4) Steroid sparing effect ; 5) Safety assessment INCLUSION CRITERIA: 1) Patients with moderately active ulcerative colitis (CAI; 7‐11) 2) Patients treated with corticosteroid (PSL; less or equal to 30mg/day, within 2 weeks) 3) Immunomodulators (azathiopurine, methotrexate, tacrolimus, cyclosporine ) naive patients 4) Anti‐TNF biologic agent naive patients