P513 Efficacy of vedolizumab in ulcerative colitis by prior treatment failure in GEMINI I, a randomised, placebo-controlled, double-blind, multi-centre trial

P513 Efficacy of vedolizumab in ulcerative colitis by prior treatment failure in GEMINI I, a randomised, placebo-controlled, double-blind, multi-centre trial B. Feagan1 *, B. Sands2, S. Sankoh3, C. Milch3, I. Fox3. 1Robarts Research Institute, University of Western Ontario, London, Canada, 2Mount Sinai School of Medicine, Division of Gastroenterology, New York, United States, 3Millennium Pharmaceuticals, Inc., Cambridge, United States