Abrilumab (AMG 181) in Adults with Moderate to Severe Crohn's Disease

- Diagnosed with ileal, ileo-colonic, or colonic Crohn’s disease for a minimum of 6 months prior to baseline - Moderately to severely active Crohn’s disease defined by a CDAI score ≥ 220 and ≤ 450 at baseline - Evidence of active inflammation within 12 weeks prior to baseline - Demonstrated an inadequate response to, loss of response to, or intolerance to at least one of the following agents: Immunomodulators and/or anti-tumor necrosis factor (TNF) agents or to corticosteroids (non-US sites only). - Neurological exam free of clinically significant, unexplained signs or symptoms during screening and no clinically significant change prior to randomization - Subject has no known history of active tuberculosis and has a negative test for tuberculosis during screening

- Short bowel syndrome - Stricture with obstructive symptoms within 3 months - Bowel surgery within 12 weeks prior baseline, or has planned bowel surgery within 24 weeks from baseline - Ileostomy and/or colostomy - Any gastric or intestinal pouch - Evidence of an infected abscess - Bowel perforation or evidence of non-inflammatory obstruction during the 6 months prior to baseline - Stool positive for C. difficile toxin at screening - Any uncontrolled or clinically significant systemic disease - Known to have tested positive for hepatitis B virus surface antigen, hepatitis C virus antibody, or human immunodeficiency virus (HIV) - Any underlying condition that predisposes subject to infections - Subject has malignancy (other than resected cutaneous basal or cutaneous squamous cell carcinoma, or treated in situ cervical cancer considered cured) within 5 years of baseline - Received an anti-TNF agent, cyclosporine, mycophenolate mofetil, sirolimus (rapamycin), thalidomide, tacrolimus, topical (rectal) aminosalicylic acid (eg, mesalamine) or topical (rectal) steroids, intravenous or intramuscular corticosteroids within protocol-specified time periods. - Any prior exposure to antagonists of integrins or integrin ligands (eg, natalizumab, efalizumab, or vedolizumab), rituximab, or TNF kinoid immunotherapies, AMG 181, or any form of cell-based transplantation - Received treatment of infection with intravenous (within 30 days of baseline) or oral (within 14 days prior to baseline) antibiotics, antivirals, or antifungals - Significant laboratory abnormalities - Pregnant or breast feeding