Assessment of Mucosal Activity to Improve the Prognosis of Patients With Crohn's Disease Treated With Immunosuppressants

This study will test that individualized treatment in patients with Crohn's Disease in remission or mild clinical activity under immunosuppressants may improve prognosis, rather than just treating flares.

Patients will be prescreened for inclusion criteria one week before the start of screening at Visit 0 (Prescreening Visit). Patients must be on stable doses of azathioprine/mercaptopurine. Patients will be given a diary to record their CD symptoms for the seven days prior to Visit 1. At Visit 1 (Screening Visit 1), patients will have their CDAI score assessed based upon their diary information. Patients with CDAI ≤ 220 will then have both calprotectin and hsCRP testing done. Patients with calprotectin \> or = 250µg/g and/or hsCRP \> or = 5mg/L will be notified and told to schedule Visit 2 within three weeks. At Visit 2 (Screening Visit 2), patients will undergo a colonoscopy. A Crohn's Disease Endoscopic Index of Severity (CDEIS) will be used to determine the endoscopic activity. Patients with significant endoscopic lesions will be notified and asked to enroll in the study. Patients will be randomized into the study at Visit 3 (Randomization Visit, same day of Visit 2 in results available). Due to the cost and invasiveness of the colonoscopy, the Screening Visit 2 colonoscopy will serve as the baseline for the study, should the patient be enrolled. Drug will also be dispensed at this visit. Eligible patients will be randomized in a 1:1 ratio to receive either adalimumab or placebo during the treatment period, along with continuing their current immunosuppressive maintenance treatment at a stable dose. Treatment in both arms will be induction at 160/80mg and maintenance on 40 mg every other week. Patients will return for follow up visits every 12 weeks until the final follow-up visit at 48 weeks (Visit 7), where another colonoscopy will be performed. Patients who terminate early from the study for any reason will be asked to return for a follow-up visit, where Visit 7 procedures will be performed. Before week 48, if a patient has an increase of more than 50% in either calprotectin and/or hsCRP over baseline and above the thresholds at any regular visit, a follow-up visit will be performed two weeks later. If the 50% increase is still observed another colonoscopy will be performed, within two weeks of the follow-up visit. If patients still have significant endoscopic lesions, study product will be intensified to 40 mg weekly. This will include patients on placebo in order to preserve the double-blind aspect of the study.