The role of biological therapy in inflammatory bowel disease.

Substantial evidence suggests a central role for TNF-alpha in the pathogenesis of IBD. This molecular observation has been supported by clinical trials with anti-TNF therapies. The most extensively investigated among the various anti-TNF agents is infliximab. Clinical trials to date have demonstrated its efficacy in inducing remission in patients with moderately active, refractory Crohn's disease (CD) and in managing patients with CD complicated by fistulas. One advantage of infliximab is its rapid onset of action. However, as expected with most medications used to treat patients with IBD, the effect of infliximab is of limited duration, with the response lasting 2-3 months in most patients. The efficacy of repeated infusions of infliximab in maintaining remission in patients with inflammatory CD has been demonstrated in one trial to date. The results from the ACCENT I trial should soon be available. Many other important questions regarding the use of infliximab remain unanswered. These include the optimal schedules of infusions, the effect of concomitant therapy with aminosalicylates, immunomodulators and antibiotics, and the timing and indication of using infliximab in the general management algorithm of a patient with CD. Certainly, the efficacy of infliximab in the treatment of ulcerative colitis (UC) remains to be further explored in a controlled fashion, though preliminary uncontrolled data suggests efficacy. As experience with infliximab use accumulates, more data will become available regarding its safety with either short-term or long-term use. A large body of evidence exists regarding the short-term safety of infliximab. The concern of increased risk of hypersensitivity-like reactions with longer interval between treatments will also need to be addressed. The currently available data supports that infliximab is safe and well tolerated. Other anti-TNF therapies will also need to be investigated with the same rigor before widespread use can be advocated. In addition to these agents, advances in molecular engineering techniques have further expanded the array of biologic therapies available to treat IBD. These newer therapies hold promise in targeting specific pathways of the pathogenesis of IBD that may be different from all prior therapies. Certainly, the anti-TNF therapies and others aforementioned have taken the field of IBD into a new and exciting generation, the biological era. (c) 2001 Prous Science. All rights reserved.