NCT03559517

Who might be able to join this trial:

• You are between 16 and 80 years old (if you are under 18, you must also weigh at least 40 kg and have a body mass index of at least 16.5)
• You have been diagnosed with moderate to severe Crohn's disease (CD) affecting the lower part of the small intestine and/or colon, confirmed by a specific activity score and symptoms such as significant abdominal pain and/or frequent loose or liquid stools
• You have ulcers in your gut that are typical of Crohn's disease, confirmed by a colonoscopy done during the screening process
• You have had a confirmed diagnosis of Crohn's disease (proven by tissue biopsy and colonoscopy) for at least 3 months before joining the study
• You are willing and able to have a colonoscopy during the screening period
• You have tried at least one standard Crohn's disease treatment (such as certain anti-inflammatory drugs, steroids, immune-suppressing medicines, or anti-TNF drugs) and it either did not work well enough, stopped working, or you could not tolerate it
• If you are already taking medication for Crohn's disease, you have been on a stable dose for the required period of time and plan to stay on it
• You are male, or a female who is not pregnant or breastfeeding; if you are able to have children and are sexually active, you must agree to use appropriate contraception throughout the study

Who may not be able to join:

• You have a type of bowel disease other than Crohn's disease, such as indeterminate colitis, microscopic colitis, ulcerative colitis, or colitis caused by medication, poor blood supply, or infection
• You have or have had abnormal or cancerous cell changes in your colon (people with a past history of non-cancerous polyps that were fully removed may still be eligible)
• You have a history of or currently have a serious complication called toxic megacolon (a dangerous swelling of the colon)
• You have an abnormal connection (fistula) between your bowel and your bladder or vagina
• You currently have symptoms of diverticulitis or diverticulosis (small pouches in the bowel wall that are causing problems)
• You have a significant blockage in your colon, have had bowel surgery in the last 6 months, are likely to need surgery for Crohn's disease during the study, or have had colon removal surgery more than 6 months ago with less than 25 cm of colon remaining
• You have had multiple small bowel surgeries that have caused significant problems with absorbing nutrients (short bowel syndrome)
• You currently need to be fed nutrients directly into your bloodstream (total parenteral nutrition)
• You have had surgery that resulted in a stoma (an opening in the abdomen for waste), or have had a j-pouch procedure
• You have previously been treated with the study drug ontamalimab (also known as PF-00547659 or SHP647)
• You are known to be allergic or intolerant to the study drug or any of its ingredients
• You have taken certain immune-modifying drugs (other than azathioprine, 6-mercaptopurine, or methotrexate) or long-term antibiotics (more than 2 weeks) for Crohn's disease within the last 30 days before the start of the study
• You have received anti-TNF treatment (a type of biologic drug) within the last 60 days before the study starts
• You have received any other type of biologic immune-modifying drug (other than anti-TNF drugs) within the last 90 days before the study starts
• You have ever received a treatment that targets integrins or adhesion molecules (such as natalizumab, vedolizumab, efalizumab, or similar drugs)
• You have had a blood filtering procedure (apheresis) within the last 60 days before the study starts
• You have received tube feeding (enteral nutrition) within the last 30 days before the study starts
• You have received steroids or anti-inflammatory drugs given directly into the rectum, or steroids given by injection or infusion, within 14 days before your screening colonoscopy
• You have taken more than a certain dose of oral steroids (e.g., more than