Abstract
BACKGROUND AND AIMS: Predicting the efficacy of molecular-targeted drugs (MTDs) is an unmet need in the treatment of ulcerative colitis (UC). Intestinal ultrasound (IUS) can be used to safely and repeatedly assess UC activity. METHODS: Thirty-eight patients who started MTD therapy for active UC and underwent IUS at baseline and 3 months after starting therapy were analyzed. Steroid-free clinical remission (SFCR) and endoscopic improvement (EI) at 6 months were defined as a Lichtiger index of ≤3 and Mayo endoscopic subscore of ≤1 while continuing the MTD without steroid induction or surgery. Sonographically estimated EI (SE-EI) at 3 months was assessed based on a Milan Ultrasound Criterion of ≤6.2 and Kyorin Ultrasound Criterion for UC (bowel wall thickness of <3.8 mm and submucosa index of <50%). RESULTS: Thirty-one patients achieved SFCR at 6 months [SFCR(+) group]. The SFCR(+) group demonstrated significantly better improvement in bowel wall thickness and bowel wall vascularity at 3 months than the SFCR(-) group. The Milan Ultrasound Criterion and UC-IUS index also improved significantly more in the SFCR(+) than SFCR(-) group. The areas under the curve of these parameters for predicting SFCR were approximately 0.80. Colonoscopy was performed for 28 patients at 6 months, and 15 patients achieved EI. SE-EI at 3 months was significantly associated with achievement of EI at 6 months. The positive predictive values of SE-EI at 3 months for SFCR and EI at 6 months were 100%. CONCLUSION: Sonographic improvements in 3 months predicted the clinical and endoscopic efficacy of MTD therapy at 6 months, suggesting the longitudinal significance of IUS monitoring for UC treatment.