Comparative Effectiveness of Ustekinumab and Vedolizumab as Maintenance Therapy After Tacrolimus-Induced Improvement in Patients with Acute Severe Ulcerative Colitis: A Retrospective Cohort Study.

Background/Objectives: Acute severe ulcerative colitis (ASUC) is often managed by tacrolimus induction therapy followed by maintenance therapy. We compared the effectiveness of ustekinumab versus vedolizumab as maintenance therapies after tacrolimus induced improvement in patients with ASUC. Methods: This single-center retrospective cohort study included patients with ASUC who received tacrolimus induction therapy followed by ustekinumab or vedolizumab between January 2018 and November 2024. The primary outcome was clinical remission at week 16. Secondary and exploratory outcomes included clinical remission at week 8, biologic persistence, and relapse risk. An inverse probability of treatment weighting (IPTW) analysis was performed using the following covariates: male sex, prior biologics or JAK inhibitors, partial Mayo score, CRP, and albumin. Results: Among 235 tacrolimus-treated patients, 29 received ustekinumab and 22 received vedolizumab. After IPTW adjustment, the clinical remission rates were significantly higher in the ustekinumab group at both week 8 (82.1% vs. 51.8%, p = 0.02) and week 16 (85.4% vs. 36.8%, p = 0.02). Biologic persistence was significantly higher in the ustekinumab group (p = 0.004), and ustekinumab significantly reduced the hazard of relapse in multivariable analyses (HR 0.42 [95% CI: 0.20-0.88], p = 0.02). Conclusions: Ustekinumab showed greater effectiveness than vedolizumab in terms of achieving remission at 16 weeks after tacrolimus induction therapy in patients with ASUC.