Acute Severe Ulcerative Colitis: An International Delphi Consensus on Clinical Trial Design and Endpoints.

Background & Aims: Interventional clinical trials in acute severe ulcerative colitis (ASUC) are characterized by substantial heterogeneity due to a lack of consensus in several key areas of trial design-this impedes clinical research efforts to identify novel therapies. The objective of this initiative was to achieve the first consensus and provide clear position statements on ASUC trial design.

Methods: A modified Delphi consensus approach was employed with a panel of 20 clinicians with international representation and expertise in ASUC trial design and delivery. Agreement was defined as at least 75% of participants voting as "agree" with each statement.

Results: In total, 30 statements achieved consensus and were approved. Statements centred on proposing suitable eligibility criteria (disease extent, disease severity, prior therapy exposure), optimizing trial design (randomization, stratification, corticosteroid handling, timing of assessments), and recommending primary and secondary endpoints alongside defining key efficacy outcomes (clinical and endoscopic response and remission, treatment failure, quality of life).

Conclusions: The expansion of drugs to treat moderate-severe ulcerative colitis over the past decade, particularly the rapidly acting Janus kinase inhibitors, is promising and has reignited the interest in identifying suitable therapeutic candidates for ASUC. Clinical trials in this high-risk population are challenging to conduct and this consensus provides a framework for future trials to advance drug development.