KEY CLINICAL UPDATES IN INFLAMMATORY BOWEL DISEASE
For patients who require more than one course of corticosteroid therapy every 1–2 years for symptomatic relapse, treatment should be ‘stepped up’ to include a thiopurine (azathioprine or mercaptopurine) or a biologic agent.
A 2020 American Gastroenterological Association guideline recommends either infliximab or vedolizumab as first-line therapies for moderate to severe colitis based on their efficacy and safety profiles.
These two agents had the highest rankings of all biologic agents for induction of clinical remission in a 2020 network meta-analysis.
Although infliximab may be the more effective agent (especially for severe disease), vedolizumab may be the preferred first-line therapy in patients who are elderly or have increased medical comorbidities due to its significantly lower incidence of infectious complications.
The term “inflammatory bowel disease” includes ulcerative colitis and Crohn disease. In the United States, there are approximately 1.6 million people with inflammatory bowel disease with adjusted annual incidences of 12.2 cases/100,000 and 10.7 cases/100,000 person-years for ulcerative colitis and Crohn disease, respectively. Ulcerative colitis is a chronic, recurrent disease characterized by diffuse mucosal inflammation involving only the colon. Ulcerative colitis invariably involves the rectum and may extend proximally in a continuous fashion to involve part or all of the colon. Crohn disease is a chronic, recurrent disease characterized by patchy transmural inflammation involving any segment of the gastrointestinal tract from the mouth to the anus.
Crohn disease and ulcerative colitis may be associated in 50% of patients with a number of extraintestinal manifestations, including oral ulcers, oligoarticular or polyarticular nondeforming peripheral arthritis, spondylitis or sacroiliitis, episcleritis or uveitis, erythema nodosum, pyoderma gangrenosum, hepatitis and sclerosing cholangitis, and thromboembolic events.
Although ulcerative colitis and Crohn disease appear to be distinct entities, several pharmacologic agents are used to treat both. Despite extensive research, there are still no specific therapies for these diseases. The mainstays of therapy are 5-aminosalicylic acid derivatives, corticosteroids, immunomodulating agents (such as mercaptopurine or azathioprine and methotrexate), and biologic agents.
A. 5-Aminosalicylic Acid (5-ASA)
5-ASA is a topically active agent that has a variety of anti-inflammatory effects. It is used in the active treatment of ulcerative colitis and Crohn disease and during disease inactivity to maintain remission. It is readily absorbed from the small intestine but demonstrates minimal colonic absorption. Several oral and topical compounds have been designed to target delivery of 5-ASA to the colon or distal small intestine. Commonly used formulations of 5-ASA are sulfasalazine, mesalamine, and azo compounds.
Mesalamine compounds are oral 5-ASA formulations that are either coated in various pH-sensitive resins (Asacol, Apriso, and Lialda) that release 5-ASA throughout the colon or packaged in timed-release capsules (Pentasa) that release 5-ASA in the small intestine and colon. Side effects of these compounds are uncommon but include nausea, rash, diarrhea, pancreatitis, and acute ...