A Study With Pentasa in Patients With Active Crohn's Disease

Inclusion Criteria (main): * Age: at least 18 years * CD symptoms/onset of disease: ≥ 3 months prior to Visit 1 * Ileal, ileo-colonic or colonic non-stricturing/non-penetrating disease * A confirmed location of CD (by MRI, X-ray (small bowel and/or colon), and/or endoscopy) * A Harvey-Bradshaw score between 5 and 12 * Males and non-pregnant, non-nursing women * Mild to moderate active CD, defined by a CDAI score between 180 and 350 * Active inflammatory disease (C-Reactive Protein (CRP) level above or equal to 5 mg/L), or a biopsy verified inflammation, or fecal calprotectin level above or equal to 50 µg/g) * Estimated creatinine clearance should be above 75 ml/min Exclusion Criteria (main): * Any significant disease or disorder which, in the opinion of the Investigator, may either put the patient at risk because of participation in the trial, or may influence the results of the trial or the patient's ability to participate in the trial * CD located to the upper gastrointestinal tract and/or jejunal part of the small intestine, and/or to colon below the left colon flexure and/or isolated proctitis and/or anal disease * Prior treatment resistance to Pentasa (mesalazine) * Chronic, dominant arthralgia or rheumatoid arthritis * Palpable abdominal mass * Biologics (eg anti-TNF-α) must not be used during the trial or 6 months before Visit 1 * Continuous usage of systemic steroids (excluding budesonide) for 3 months or more within the past year * Positive pregnancy test