Newer Therapies for Inflammatory Bowel Disease

Recent controlled and uncontrolled trial data in inflammatory bowel disease have suggested several new avenues of possible therapies and refined our understanding of the uses and selectiveness of anti-tumor necrosis factor (TNF)-based therapies. Infliximab remains the only proven effective anti-TNF therapy, whereas others have proven ineffective (etanercept, CDP-571) or of limited utility (thalidomide, CDP-870). A Crohn's disease Clinical trial Evaluating infliximab in a New long-term Treatment regimen (ACCENT I) and ACCENT II trials supported the strategy of using 5 to 10 mg/kg of infliximab on an every 8-week basis for maintenance of remission, although in clinical practice many physicians take variable approaches to maintenance of remission dosing schedules. On the other hand, no controlled trial data to date have supported the use of infliximab in ulcerative colitis. Therapies utilizing novel mechanistic approaches, such as hematopoietic growth factors, mitogen-activated protein (MAP)-kinase inhibition, and peroxisome proliferator activated receptor gamma ligand receptor binding have shown promise in small uncontrolled trials and await confirmation of their utility in randomized, placebo-controlled trials. Newer biologic (natalizumab) or cytokine-based therapies (monoclonal antibody to interleukin-6) have shown preliminary evidence of efficacy in controlled trials, but neither have yet been approved by the US Food and Drug Administration and, therefore, have not been commercialized. However, tacrolimus, a potent calcineurin inhibitor and inhibitor of interleukin-2 expression, has shown efficacy in Crohn's disease, albeit at the cost of substantial potential toxicity.