Acute severe ulcerative colitis trials: the past, the present and the future.

Acute severe ulcerative colitis (ASUC), characterised by bloody diarrhoea and systemic inflammation, is associated with a significant risk of colectomy and a small risk of mortality. The landmark trial of cortisone in 1955 was pivotal for two reasons: first, for establishing the efficacy of a drug that remains a first-line therapy today and, second, for producing the first set of disease severity criteria and clinical trial endpoints that shaped the subsequent ASUC trial landscape. Trials in the 1990s and at the turn of the millennium established the efficacy of infliximab and ciclosporin, but since then, there has been little progress in drug development for this high-risk population. This systematic review evaluates all interventional randomised controlled trials (RCTs) conducted in patients hospitalised with severe UC. It provides an overview of the efficacy of treatments from past to present and assesses the evolution of trial characteristics with respect to study populations, eligibility criteria and study designs over time. This review details ongoing RCTs in this field and provides a perspective on the challenges for future clinical trial programmes and how these can be overcome to help deliver novel ASUC therapies.