Outcomes of placebo therapy in inflammatory bowel disease

Placebo is important in assessing drug response, particularly in diseases characterized by spontaneous periods of acute exacerbation and quiescence. Randomized, placebo-controlled trials are the most objective means of evaluating drug efficacy, although the conduct of such clinical trials may not always be practical or ethical in all disease states. In inflammatory bowel disease (IBD), most patients experience intermittent episodes of active disease alternating with variable periods of remission. Thus, development of new medical therapies for IBD requires proof of superiority to placebo or alternative therapies. In this regard, knowledge of the outcomes of patients receiving placebo therapy and their influencing factors is important for proper study design and meaningful results. Such knowledge also is essential for interpreting results of open-label studies often necessary before randomized controlled trials can be conducted. In addition, the disease course of placebo-treated patients in clinical trials of IBD serves as an approximation of the natural history of these patients. The knowledge of placebo response in these patients provides clinicians with an important piece of information in prognosticating and making management decisions. This review presents our current knowledge of placebo therapy in IBD. Specifically, the existing literature on the outcomes and predictors of outcomes in patients receiving placebo therapy in clinical trials of IBD is reviewed.