The purpose of this study is to assess whether withdrawal of aminosalicylate (5-ASA) is non-inferior to continuation of 5-ASA therapy in Crohn's disease (CD) subjects in remission.

Aminosalicylate (5-ASA) agents have proven effective for inducing and maintaining remission in mild to moderate ulcerative colitis (UC) and thus are commonly used as first-line agents for patients with Crohn's disease (CD) in remission. However, there is uncertainty regarding their effectiveness for CD.

In this open-label, randomized study, participants with CD in remission will be allocated to either continue their 5-ASA therapy or withdraw their 5-ASA. The purpose is to investigate if withdrawal of 5-ASA therapy is not unacceptably less effective than continuing on 5-ASA in maintaining CD remission over a 24 month period.

Inclusion Criteria:

• Documented diagnosis of CD at least 3 months prior to enrollment
• Taking any brand or dosage of an oral aminosalicylate for at least 6 months
• Subject-confirmed compliance with current aminosalicylate therapy (taking at least 75% of prescribed doses)
• CD currently in clinical remission
• Able to participate fully in all aspects of the clinical trial
• Written informed consent obtained and documented

Exclusion Criteria:

• A current diagnosis of UC, indeterminate colitis, microscopic colitis, or diverticular disease-associated colitis
• A diagnosis of short-bowel syndrome
• Active perianal disease
• Active fistulizing disease
• A flare of CD within 3 months prior to enrollment requiring initiation/escalation of medical therapy or surgery
• Use of systemic corticosteroids for CD (2 continuous weeks or more) within 3 months prior to enrollment
• Any major resective bowel surgery for CD (ileal resection, ileocecal resection, proctocolectomy, colectomy, enterectomy, ostomy formation and repair, anastomosis/reanastomosis) within 6 months prior to enrollment
• Unwillingness to stop taking aminosalicylates for the duration of the trial
• Untreated bile salt malabsorption that, in the opinion of the investigator, may interfere with accurate study HBI assessment
• Serious underlying disease other than CD that, in the opinion of the investigator, may interfere with the subject's ability to participate fully in the study
• History of active alcohol or drug abuse that, in the opinion of the investigator, may interfere with the subject's ability to comply with the study procedures
• Currently participating in another interventional trial, or previous participation within the last 3 months