An induction or flare of arthritis and/or sacroiliitis by vedolizumab in inflammatory bowel disease: a case series.

<bold>Background: </bold>In inflammatory bowel disease (IBD), a new biological therapy has recently been approved. Vedolizumab is a humanised IgG1 monoclonal antibody to α4β7 integrin that modulates gut lymphocyte trafficking. Although an exclusively local effect of vedolizumab could be expected based on the restricted presence of the α4β7-mucosal vascular addressin cell adhesion molecule 1 complex in the gut, past combined success with anti-tumour necrosis factor, and previous demonstration of α4β7 integrin in the joint, led to the expectation of a therapeutic efficacy in spondyloarthritis. Nonetheless, the effect of vedolizumab on extraintestinal manifestations-and especially the joint-has not been reported so far.<bold>Case Report: </bold>A series of five patients with IBD who were treated with vedolizumab and promptly developed new onset or exacerbation of sacroiliitis or arthritis are reported.<bold>Conclusions: </bold>Vedolizumab therapy does not seem to show any efficacy in and might even induce arthritis and/or sacroiliitis. However, larger cohort studies are needed to provide information on the prevalence, the evolution and underlying mechanism. [ABSTRACT FROM AUTHOR]