Progressive Multifocal Leukoencephalopathy (PML). People with weakened immune systems can get progressive multifocal leukoencephalopathy (PML) (a rare, serious brain infection caused by a virus). Although unlikely while receiving ENTYVIO, a risk of PML cannot be ruled out. PML can result in death or severe disability. There is no known treatment, prevention, or cure for PML. Tell your healthcare provider right away if you have any of the following symptoms: confusion or problems thinking, loss of balance, change in the way you walk or talk, decreased strength or weakness on one side of the body, blurred vision, or loss of vision., ENTYVIO is a biologic treatment for moderate to severe Crohn's disease (CD) or ulcerative colitis (UC). See Safety and Prescribing Information., See the impact of ENTYVIO (vedolizumab) in reducing symptoms and achieving remission for Crohn’s disease. See Safety and Prescribing Information..