Ulcerative Colitis - Vedolizumab- With/Without Prior Exposure to Anti-TNF（Tumor Necrosis Factor）Therapy

Inflammatory bowel disease (IBD)- ulcerative colitis (UC) and Crohn's disease (CD)- are chronic conditions of the gastrointestinal tract. Treatment generally consists of immunosuppression to modify the dysregulated immune responses. Vedolizumab, an inhibitor of α4β7, is a highly effective therapy for treating IBD, that minimized adverse effects through its gut selective inhibition of lymphocyte trafficking. However, the mechanism of action remains incompletely characterized especially in those previously treated to other biologics and why some patients are either vedolizumab non-responders or fail to respond over time. We would like to address the question whether anti-TNF non-responders as well as those that either do not respond or fail overtime to respond to vedolizumab identifies a specific population with difficult to treat disease that have alternate trafficking patterns and whether prior exposure to anti-TNF alters the mucosal immune responses, and/or trafficking patterns when compared to anti-TNF naive patients that may help explain impaired response to vedolizumab induction therapy.