Efficacy and Safety of Discontinuing 5-ASA in Patients With Inflammatory Bowel Disease

In inflammatory bowel disease (IBD), 5-aminosalicylic acid (5-ASA) is widely used as a first-line treatment for ulcerative colitis (UC) and is still prescribed for Crohn's disease (CD). However, for patients who do not respond to conventional therapy, anti-tumor necrosis factor (anti-TNF) agents have become an effective alternative. This has led to ongoing debate about whether continued use of 5-ASA is necessary after transitioning to anti-TNF therapy. Recent retrospective studies have reported that discontinuing 5-ASA after initiating anti-TNF therapy in UC and CD patients does not increase the risk of clinical adverse outcomes such as new steroid use, hospitalization, or bowel surgery. However, a study based on U.S. data had a median follow-up period of less than one year, making it difficult to assess long-term effects. Additionally, studies on relapse risk after discontinuing 5-ASA have identified younger age, extensive disease, and frequent relapses as risk factors, but detailed analyses for patients receiving anti-TNF therapy remain insufficient. Another critical issue is the economic burden of continued 5-ASA treatment. In South Korea, the annual cost of the most commonly used 5-ASA formulations constitutes a significant portion of overall healthcare expenses. Discontinuing 5-ASA could reduce treatment costs, simplify therapy, improve patient adherence, and minimize adverse effects associated with polypharmacy. Regarding colorectal cancer (CRC) prevention, recent trends indicate a decreasing incidence of CRC in IBD patients. Since mucosal inflammation is considered a primary driver of CRC, additional 5-ASA use may not be necessary if mucosal healing is achieved through biologics or small-molecule therapies. Accordingly, this study aims to evaluate the long-term outcomes of discontinuing 5-ASA in UC and CD patients receiving stable biologic or immunomodulator therapy.