Introduction: Therapeutic peptides in inflammatory bowel diseases essentially comprise cytokines affecting immune response, growth factors and monoclonal antibodies directed against key targets of mucosal inflammation, in particular, tumor necrosis factor-a (TNF-a). The latter have revolutionized standard medical treatment which previously was restricted to mesalamine, corticosteroids or classical immunosuppressants.
Areas covered: We review current evidence of the use of the so-called biologicals, including the well-established TNF-a antagonists and novel peptides and monoclonal antibodies developed for these diseases. The focus is on controlled clinical trials and meta-analyses, if available. Limitations and biases of these studies are important but tend to be ignored. Safety is also an important issue with opportunistic infections and lymphoma as relevant risks. There is significant heterogeneity between different countries, guidelines and opinions within the scientific community regarding clinical indications, even apart from pharmacoeconomics and reimbursement.
Expert opinion: TNF blockers have greatly extended medical options in inflammatory bowel diseases. Their more or less extensive use in nearly all patients or only a few selected indications is a matter of debate. It proved difficult to reproduce this success with other antibody targets as well as with immunomodulatory cytokines and growth factors. The most promising novel peptide is vedolizumab, an antibody against α4β7 integrin.