A newer monoclonal antibody, vedolizumab, binds only to α4β7 which results in selective inhibition of leukocyte trafficking to the intestine and theoretically eliminates the risk of PML. Vedolizumab was approved by the FDA in 2014 based on a randomized controlled trial of 368 patients with refractory CD treated with vedolizumab which demonstrated a significant induction of clinical remission in this cohort (14.5% vs 6.8%, p=0.02) . Similar to natalizumab, a subgroup analysis demonstrated that 10.5% of patients refractory to anti-TNFα therapies will respond to vedolizumab. Among vedolizumab responders who were randomized to maintenance vedolizumab, responders were more likely to be in clinical remission at week 52 compared to patients not on maintenance therapy (39% vs 22%, p=0.001).