Biologics, small molecule therapies and surgery in small bowel Crohn's disease

The terminal ileum and small bowel (SB) are involved in 30-45% of patients with Crohn's disease, while 20% have both small and large bowel involvement. Ileal Crohn's is associated with higher risk of progression to stricturing and penetrating disease 1 , hence it's imperative to utilize effective therapies to induce and maintain clinical and endoscopic remission and prevent intestinal complications. We review the available data of biologics and upadacitinib in small bowel disease, and the emerging data on the role of surgery as first line therapy for isolated Crohn's ileitis.

Most trials assessing drug efficacy do not report efficacy by disease location, and robust data on efficacy of therapies in isolated small bowel Crohn's is sparse. Several studies indicate that small bowel disease is generally less responsive to biologics, and could require higher drug trough levels to achieve endoscopic healing.

Current therapies for induction and maintenance of remission in moderate to severe Crohn's disease include several classes of monoclonal antibodies and a Janus Kinase inhibitor, upadacitinib. While small bowel Crohn's disease is generally less responsive to treatment, anti-TNFs are still preferred as first line therapy, and the option of early ileocecal resection in early limited ileal disease is gaining interest.