A Study to Evaluate Efficacy, of Early Versus Late Use of Vedolizumab in Crohn's Disease: the LOVE-CD Study

Inclusion Criteria: 1. In the opinion of the investigator, the subject is capable of understanding and complying with protocol requirements. 2. The subject signs and dates a written, informed consent form and any required privacy authorization prior to the initiation of any study procedures. 3. Age 18 to 80 4. Male or non-pregnant, non-lactating females. Females of child bearing potential must have a negative serum pregnancy test prior to randomization, and must use a hormonal (oral, implantable or injectable) or barrier method of birth control throughout the study. Females unable to bear children must have documentation of such in the source records (i.e., tubal ligation, hysterectomy, or post-menopausal \[defined as a minimum of one year since the last menstrual period\]). 5. Established diagnosis of ileal, ileocolonic or colonic Crohn's disease with histopathological confirmation available in the record of the patient. 6. Moderately to severely active CD (CDAI 220-450) with objective evidence of ulcerations visualized on endoscopy. 7. Anti-TNF discontinued for at least 4 weeks prior to baseline. GROUP 1 (EARLY CD): 8. Diagnosis of CD \< 24 months prior to enrollment 9. Demonstrated failure to respond to topical or systemic corticosteroids or intolerance to corticosteroids or: need for \> 2 courses of steroids since diagnosis or: steroid dependency at any dose since diagnosis and additionally, but not mandatory, lack of efficacy of thiopurines or intolerance to thiopurines (any duration). Patients who are using thiopurines at screening must have used them for \> 3 months (last 4 weeks at stable dose). GROUP 2 (LATE CD) 10. Demonstrated failure to respond to at least 3 months of thiopurines or intolerance to thiopurines and: failure to respond to at least 1 anti-TNF or intolerance to anti-TNF or loss of response to at least 1 anti-TNF. Exclusion Criteria: 1. Previous exposure to any anti-integrin antibodies including- vedolizumab ; α4β7 anti-bodies ; β7 antibodies ; anti- MADCAM-1 2. Contraindication for endoscopy. 3. History of colonic dysplasia/cancer 4. Presence of stoma 5. Received other biologics within the last 4 weeks of baseline 6. Use of 5-aminosalicylic acid (5-ASA) or corticosteroid enemas/suppositories within 2 weeks of enrollment 7. Chronic hepatitis B or C infection 8. Evidence of or treatment for C. difficile infection or other intestinal pathogen at screening within 4 weeks prior to enrollment 9. Active or latent tuberculosis 10. Conditions which in the opinion of the investigator may interfere with the subject's ability to comply with the study procedures. 11. Received any investigational drug in the past 30 days or 5 half-lives, whichever is longer. 12. Positive progressive multifocal leukoencephalopathy ( PML) subjective symptom checklist before enrollment. 13. Subjects with known allergy or hyposensitivity to vedolizumab or its components