Sonographic Transmural Induction Outcomes Across Advanced Therapies in Crohn's Disease

Intestinal ultrasound (IUS) is increasingly being used to evaluate induction efficacy in both clinical practice and clinical trials. We aimed to quantify the rates of induction IUS transmural (TM) remission and response across advanced therapies (AT) in Crohn's disease (CD).

Single-center retrospective review of patients with CD initiating AT with IUS pre- and post-induction. Primary outcome was induction TM segmental response (> 25% decrease in bowel wall thickness (BWT), absolute BWT decrease > 2 mm, or absolute BWT decrease > 1 mm with ≥ 1-point improvement in Modified Limberg Score (MLS) for bowel wall hyperemia of 0-3). Secondary outcomes were segmental and complete (all segments) TM remission (BWT ≤ 3.0 mm and MLS 0). Descriptive statistics summarized data (median [IQR]): univariate and multivariate tested associations.

101 patients (53% female, age 17.4 years [15.0-21.1]); disease duration 0.80 years [0.17-3.96]. IUS performed 78 [56-102] days on AT (44% anti-TNF, 53% AT naïve). Segmental TM induction response and remission across all AT were 63% and 36%, respectively. Complete TM remission was 35% and was independently associated with infliximab (aOR 12.9 [2.1-79.8]), upadacitinib (aOR 10.4[1.4-75.4]), as well baseline MLS 3 (aOR 0.20[0.049-0.79]) and loss of bowel wall stratification on baseline IUS (aOR 0.21[0.056-0.77]).

Transmural induction outcomes are achievable across multiple advanced therapies, with 2/3 of patients achieving a response and 1/3 of patients achieving complete remission. These data, combined with the high correlation between IUS and endoscopy, suggest that IUS response could be considered as a clinical trial endpoint.