Complications of biological therapy for inflammatory bowel diseases.

The purpose of this review is to analyze the complications associated with treatment of inflammatory bowel disease with biologic agents. There have been various biologic agents evaluated in patients with inflammatory bowel disease; that is, Crohn's disease and ulcerative colitis. Thus far only infliximab has been approved by the US Food and Drug Administration as induction and maintenance treatment in patients with active Crohn's disease (moderate-to-severe and/or fistulizing) who are refractory to conventional therapy. Recent data from two large multicenter, multicountry, randomized controlled clinical trials have demonstrated that infliximab is efficacious also for the treatment of ulcerative colitis. Other biologics considered potentially efficacious are still undergoing evaluation in various clinical trials. The data concerning biologics' associated toxicity in patients with inflammatory bowel disease are the most robust in the case of infliximab. These data are derived from both prospective, randomized clinical trials and from post-marketing experience. In the case of the remaining agents the data concerning safety in inflammatory bowel disease are limited, as these agents were not evaluated in as many trials as infliximab; indeed, some of them included only several patients.