Treatment is on target in Crohn’s disease with biologic agents

Crohn’s disease is a disorder of unknown aetiology, which classically presents with transmural inflammation throughout the gastrointestinal tract, from the mouth to the perianal area. Patients with Crohn’s disease suffer from various non-specific symptoms such as prolonged diarrhoea, abdominal pain, fever and weight loss. To date, treatment has largely involved immunosuppression, but the recent development of a novel class of drugs, the biologics, may revolutionise the treatment of Crohn’s disease. Biologic treatments used in Crohn’s disease include tumour necrosis factor alpha inhibitors (anti-TNFα), adhesion molecule inhibitors, and interleukin-12 (IL-12) and interleukin-23 (IL-23) inhibitors. These biologics target the underlying immunopathogenesis seen in Crohn’s disease, primarily by decreasing pro-inflammatory cytokines. This article reviews the literature to date on infliximab, an anti-TNFα used in moderate to severe Crohn’s disease, and ustekinumab, an IL-12 and IL-23 inhibitor, with a specific focus on mechanisms of action, adverse events, and guidelines for these treatments.