thiopurine + vedolizumab

Thiopurine + vedolizumab is a combination therapy used primarily in the management of inflammatory bowel diseases (IBD), specifically Crohn's disease (CD) and ulcerative colitis (UC). This regimen combines a thiopurine immunomodulator—such as azathioprine or 6-mercaptopurine—with vedolizumab, a humanized monoclonal antibody. Thiopurines act as purine antimetabolites, suppressing lymphocyte proliferation and inducing T cell apoptosis by inhibiting DNA synthesis and Rac1 activation. Vedolizumab selectively targets the α4β7 integrin on lymphocytes, blocking their interaction with mucosal vascular addressin cell adhesion molecule 1 (MAdCAM-1), thereby preventing gut-specific migration of leukocytes into inflamed gastrointestinal tissue. The combination aims to reduce treatment failure rates in IBD patients; evidence suggests it may lower risk of treatment failure compared to vedolizumab monotherapy in Crohn’s disease but not consistently in ulcerative colitis.