Value of Pharmacokinetic Assays in the Prediction of Therapeutic Response in Ulcerative Colitis

Blood samples will be systematically collected at W0, W2, W6, W14 and W52 for vedolizumab pharmacokinetic parameters, including the vedolizumab trough levels and the specific anti-vedolizumab antibody. A supplementary blood sample will be collected at W10 which is the point where a significant greater number of patients were in remission.

Rectosigmoidoscopy will be performed in each center at time points W0, W10 and W52.