An evidence-based review of natalizumab therapy in the management of Crohn's disease.

Treatment options for Crohn's disease have evolved beyond the early goals of induction and remission and are now more focused on preventing complications by altering the natural history of the disease. The advent of biologic therapies has revolutionized the management of Crohn's disease. Specifically, antibodies to tumor necrosis factor alpha induce rapid mucosal healing. This translates into improved patient outcomes. However, many patients will fail these and other therapies. Natalizumab is a new biologic agent that has been approved for the treatment of moderately to severely active Crohn's disease in patients who have failed or are intolerant to immunosuppressants and/or tumor necrosis factor inhibitors. It is a selective adhesion molecule inhibitor to alpha-4 integrin resulting in inhibition of the migration of inflammatory cells across the endothelium. This unique mechanism of action has been shown to be effective in the treatment of Crohn's disease, making it an important option for otherwise refractory patients. Its use has been limited to these refractory patients because of concerns about the development of complications, especially progressive multifocal leukoencephalopathy. In this review, evidence-based data on the indications, efficacy and safety of natalizumab will be presented and its role in the management of patients with Crohn's disease will be defined.