Investigational agents for Crohn's disease.

IMPORTANCE OF THE FIELD: Increased understanding of the biological mechanisms of Crohn's disease has opened the door to a large number of new molecules; some of these are approved for clinical use, while others remain under evaluation. In this review, we examine the clinical efficacy of all the new drugs that have been evaluated in controlled trials in the last 12 years. AREAS COVERED IN THIS REVIEW: Anti-TNF therapy has been reviewed briefly, given the many comprehensive reviews on this topic; attention is focused mainly on the other biological therapies. In assessing the clinical efficacy of these molecules, we consider only the remission rate, as this is considered the most meaningful end point in clinical practice. WHAT THE READER WILL GAIN: We analyzed the main biological mechanisms of Crohn's disease and the new drugs whose use is based on insights into these mechanisms. We reviewed the following new drugs: probiotics, GM-CSF, IL-10, IL-11, anti-IL-6, anti-IL-12/-23, everolimus, anti-IFN-γ, IFN-β-I, co-stimulators, anti-integrins, anti-intercellular adhesion molecule 1, small molecules and mitogen-activated protein kinase inhibitors. TAKE HOME MESSAGE: Anti-TNF therapies remain the best options, followed by anti-integrin drugs. The most promising new therapies are anti-IL-23, but further data are necessary. The disappointing results with other molecules may depend on the quality of trials and possibly on inadequate dosage of the drug.