Emerging biologics in inflammatory bowel disease.

Early biologic therapy is recommended in patients with inflammatory bowel disease and poor prognostic factors and in those refractory to conventional medications. Anti-tumor necrosis factor (anti-TNF) agents are the most commonly used biologic agents. However, some patients may not have an initial response to anti-TNF therapy, and one-third will develop loss of response over time. Anti-TNF drugs can also be associated with side effects. In addition, the use of biologics is currently limited by their cost, especially in developing countries. A number of new therapeutic targets, including novel small molecules, and cellular therapy are available or under investigation. These novel molecules include oral Janus kinase (JAK) inhibitor (tofacitinib), interleukin inhibitor (ustekinumab), oral SMAD7 antisense oligonucleotide (mongersen), and anti-integrin inhibitors (vedolizumab). Here, we review the mechanisms of action, the efficacy, and the safety data of these novel agents. Biological products that are highly similar to reference biologic products whose patents have expired-also known as "biosimilars"-can be produced at lower cost with similar efficacy, and are also available for the treatment of IBD. We review the efficacy data for such agents as well.