AbstractBackgroundTo demonstrate treatment efficacy in Crohn’s disease (CD), regulatory authorities require that trials include an endoscopic remission/response end point; however, standardized endoscopic assessment of disease activity, such as the Simple Endoscopic Score for Crohn’s Disease (SES-CD), is not typically recorded by clinicians in practice or outside of clinical trials. The novel Simplified Endoscopic Mucosal Assessment for Crohn’s Disease (SEMA-CD) was developed to be easy to use in routine clinical practice and as a trial end point. We conducted a study to assess and validate the reliability and feasibility of SEMA-CD as a measure of endoscopic disease activity.MethodsPre- and post-treatment ileocolonoscopy videos of pediatric (n= 36) and adult (n= 74) CD patients from 2 ustekinumab clinical trials were each scored with SEMA-CD by 2 to 3 professional central readers, blinded to clinical history and other video scorings; the correlation between SEMA-CD and SES-CD previously completed during the trials was assessed. Sensitivity to change, inter- and intrarater reliability, and comparative ease of scoring were also assessed.ResultsThe SEMA-CD strongly correlated with SES-CD (Spearmanρ= 0.89; 95% confidence interval, 0.86-0.92). Pre- to post-treatment changes in SEMA-CD vs in SES-CD were strongly correlated, and the correlation remained strong between the scores when compared by study population (pediatric, adult), disease severity, and video quality. Intra- and inter-rater reliability were good, and SEMA-CD was rated easier than SES-CD to score 63.0% of the time, although slightly more difficult than SES-CD to score <1.0% of the time.ConclusionsThe SEMA-CD is reliable, reproducible, sensitive to change, and easy to use in both pediatric and adult patients with CD.