WS The first line of therapy for ulcerative colitis (UC) is the safe and effective 5-aminosalicylate (5-ASA) class of drugs. These include sulfasalazine, delayed-release mesalamine (Asacol, Procter & Gamble), controlled-release mesalamine (Pentasa, Shire), olsalazine (Dipentum, Pfizer) and balsalazide (Colazal, Salix), as well as the forthcoming multimatrix formulation. These drugs are clearly effective for the induction and maintenance of clinical remission in patients with mild-to-moderate UC. This is in contrast to Crohn’s disease, where the efficacy of mesalamine is not clear. Antibiotic therapies, which are used in Crohn’s (although of questionable efficacy) are not effective in UC.

Thus, in patients with UC, there is a clear first-line therapy that satisfactorily treats a substantial fraction of patients, both inducing and maintaining remission. In contrast, in Crohn’s disease, there is no safe and effective first line for inducing and maintaining remission. Further, it has been documented that over a disease course of 20 years, 80% of patients with Crohn’s disease will require at least 1 surgical resection. In the modern era, in comparable patients with UC, rates of surgery are not more than 15–20% and thus the prognosis for avoiding surgical resection is very different.