Development and validation of receptor occupancy pharmacodynamic assays used in the clinical development of the monoclonal antibody vedolizumab

Background Vedolizumab is a monoclonal antibody approved for use in ulcerative colitis and Crohn's disease. By specifically binding to α 4 β 7 integrin, vedolizumab prevents trafficking of lymphocytes to the gut, thereby interfering with disease pathology. During the clinical development program, the pharmacodynamic effect of vedolizumab was evaluated by 2 flow cytometry receptor occupancy assays: act‐1 (ACT‐1) and mucosal addressin cell...