Vercirnon (GSK-1605786, CCX-282, nTraficet-EN) is a selective, and potent antagonist of human CCR9. Vercirnon binds to the intracellular side of the receptor, exerting allosteric antagonism and preventing G-protein coupling. CCR9 is a tissue-specific lymphocyte trafficking molecule that selectively attracts both B- and T-cells to the small gut. Inhibition of CCR9 by GSK-1605786 may inhibit B- and T-cell entry to the small gut and ameliorate inflammation while leaving immune function at other anatomical sites unaffected. Vercirnon is an orally bioavailable, anti-inflammatory agent that is being developed by ChemoCentryx for treatment of inflammatory bowel disease with an initial focus in Crohn's disease. A pivotal phase III programme of vercirnon was initiated in patients with moderate-to-severe Crohn's disease, however, the programme was suspended when the first pivotal trial failed to meet its primary endpoint. Phase II trials for ulcerative colitis and celiac disease were conducted, however investigations for ulcerative colitis were suspended while no further development has been reported for celiac disease.