Risk factors and clinical characteristics of colonization and infection in patients with inflammatory bowel disease exposed to Vedolizumab: a multicenter retrospective study.

Background: Vedolizumab (VDZ), a humanized monoclonal antibody that selectively inhibits the binding of the α4β7 integrin, has been approved for treating inflammatory bowel disease (IBD). Long-term safety studies of VDZ in clinical trials identified infection (CDI) as the major opportunistic infection.

Objectives: We aimed to address the incidence and risk factors of colonization (CDC) and CDI in a real-world setting among IBD patients treated with VDZ.

Design: Retrospective multicenter study.

Methods: We retrospectively included IBD patients who tested negative for before initiating standard VDZ therapy at four tertiary hospitals from November 1, 2021, to November 31, 2023. The primary outcome was the occurrence of CDC after VDZ initiation, and the secondary outcome was the occurrence of CDI and severe CDI.

Results: A total of 454 patients were included in the final analysis. The median follow-up time was 12.9 (8.2-16.3) months, and the study was followed for 2488.6 person-months. The CDC occurred in 28 patients (6.2%), including 23 (11.4%) patients with ulcerative colitis (UC; 18 asymptomatic carriers and 5 with symptomatic CDI) and 5 (2.0%) patients with Crohn's disease (asymptomatic carriers). Multivariate analysis showed that age >40 years old and UC were independent risk factors for the occurrence of the CDC after VDZ initiation. The incidence of CDI was 1.1%, and all patients were able to continue VDZ therapy after receiving antibiotic treatment. No risk factors were found to be significantly associated with CDI. There were no cases of severe CDI or deaths within 30 days.

Conclusion: The incidence of CDC after VDZ treatment was 6.2% and the majority of patients identified as asymptomatic carriers and were able to continue VDZ treatment. Age (>40 years old) and UC were the risk factors for CDC.