P0368 Novel endoluminal parameters to predict primary loss of response in patients with Crohn’s disease: a national survey and multi-centre study
Authors: Shen J , Feng Q , Yao R , Cai C , Liang J , Tian F , Cao X , Li Y , Gu Y ,   Mimic Inflammatory Bowel Disease Research Group
Published: January 2025

Abstract

Background
Approximately 30% of patients with Crohn’s disease (CD) experience primary loss of response (PLR) administrated with ustekinumab (UST) [1]. Unlike the assessment of traditional biologic treatments, there is still a lack of studies that thoroughly integrate imaging parameters to evaluate the response of UST for Crohn’s disease. This study aims to precisely quantify endoluminal and intestinal wall parameters from computed tomography enterography (CTE) and predict PLR.

Methods
This multicentre study included 466 segments from 161 CD patients between March 2020 and May 2024. A national survey and voting were conducted to identify indicators of disease activity and PLR prediction. Ten CTE parameters were selected to evaluate changes before and after UST treatment. Logistic regression models were developed, and area under the curve (AUC), integrated discrimination improvement (IDI), net reclassification improvement (NRI), and calibration curves were used to evaluate model performance in validation cohorts.

Results
Ten CTE parameters, representing length, luminal narrowing, and bowel wall thickness, were defined through a national survey to characterize lesion features in IBD, including newly introduced metrics: length, area, effective luminal diameter, mean bowel wall thickness, and stenosis. A total of 352 baseline segments and 114 follow-up segments from 161 patients across six centres were analyzed to evaluate changes in CTE parameters following UST treatment. Eight endoluminal parameters—minimum diameter, maximum diameter, effective luminal diameter, area, bowel wall thickness, relative thickness, and stenosis—demonstrated statistically significant changes after UST treatment (p &lt; 0.001), with significantly greater improvements observed in the non-PLR group compared to the PLR group (six parameters achieve p values less than 0.001). The novel parameter “effective luminal diameter” emerged as an independent predictor of UST response, demonstrating strong discriminative performance with an AUC of 0.858 and an accuracy of 0.780 in the validation cohorts. The final prediction model was: p = -3.156 + 0.776 × Diameter. Accordingly, when the Diameter at the narrowest point of the diseased bowel segment exceeds 3.351 mm, or the Area surpasses 8.819 mm², the patient is predicted to exhibit a PLR to UST.

Conclusion
Novel endoluminal parameters, including effective luminal diameter, provide a comprehensive characterization of intestinal lesions in IBD and exhibit robust predictive value for PLR in UST-treated CD patients. These parameters offer a practical and accessible tool for quantifying intestinal lesions, with the potential to enhance treatment strategies and improve patient outcomes.

References
[1]Feagan BG, Sandborn WJ, Gasink C, Jacobstein D, Lang Y, Friedman JR, Blank MA, Johanns J, Gao LL, Miao Y, Adedokun OJ, Sands BE, Hanauer SB, Vermeire S, Targan S, Ghosh S, de Villiers WJ, Colombel JF, Tulassay Z, Seidler U, Salzberg BA, Desreumaux P, Lee SD, Loftus EV, Jr., Dieleman LA, Katz S, Rutgeerts P, Group U-I-US. Ustekinumab as Induction and Maintenance Therapy for Crohn’s Disease. N Engl J Med. 2016 Nov 17;375(20):1946-1960.