Effectiveness and safety of tacrolimus versus infliximab as rescue therapy for intravenous corticosteroid-refractory acute severe ulcerative colitis: a multicenter cohort study.

BACKGROUND & AIMS: Acute severe ulcerative colitis (ASUC) refractory to intravenous corticosteroids (IVCS) is a major clinical challenge with limited rescue therapy options. Although tacrolimus has been proposed as a potential rescue therapy, its effectiveness and safety compared with infliximab, widely used in this setting, remain unclear. METHODS: A multicenter retrospective cohort study was conducted across 34 Japanese institutions, including hospitalized patients with IVCS-refractory ASUC who received infliximab or tacrolimus as rescue therapy between January 2014 and March 2023. The primary outcome was clinical remission at day 14, using two-item patient-reported outcome scoring. Secondary outcomes included clinical response at day 3 and 7, colectomy, and adverse events within 56 days. A modified Poisson regression model was used for analysis. RESULTS: Among 300 patients (infliximab, n = 113; tacrolimus, n = 187), clinical remission at day 14 occurred in 41.6% and 33.7%, respectively, with no difference (adjusted risk ratio [RR] 0.87 [95% CI: 0.65, 1.17]). Clinical response at day 3 was lower with tacrolimus (infliximab 42.5% vs tacrolimus 24.1%; adjusted RR 0.58 [95% CI: 0.42, 0.80]) but did not differ at day 7 (infliximab 63.7% vs tacrolimus 51.9%; adjusted RR 0.83 [95% CI: 0.69, 1.01]). No difference in colectomy within 56 days was observed, although rates were higher in the tacrolimus (13.3% vs 20.3%; adjusted RR 1.58 [95% CI: 0.93, 2.67]). Adverse events were similar between groups (infliximab 8.8% vs tacrolimus 7.5%; adjusted RR 0.77 [95% CI: 0.37, 1.57]). CONCLUSIONS: Tacrolimus demonstrated comparable effectiveness and safety to infliximab as rescue therapy for IVCS-refractory ASUC, although early response was slower.