Early Intestinal Ultrasound Predicts Long-Term Endoscopic Response to Biologics in Ulcerative Colitis

Background and Aims: The Milan ultrasound criteria [MUC] is a validated score to assess endoscopic activity in ulcerative colitis [UC]. MUC>6.2 detects Mayo endoscopic score [MES]>1. In this study we evaluated the predictive value of MUC for biologic treatment response, using colonoscopy [CS] as a reference standard. Methods: Consecutive UC patients starting biologic therapy were included, and underwent CS, IUS, clinical assessment and faecal calprotectin [FC] measurement at baseline and within 1 year. In addition, IUS, clinical and FC assessments were performed at week 12. The primary objective was to evaluate whether ultrasound improvement [MUC <= 6.2] at week 12 predicted endoscopic improvement at reassessment [MES <= 1]. Endoscopic remission was defined as MES=0. Results: Forty-nine patients were included [59% under infliximab, 29% under vedolizumab, 8% under adalimumab, 4% under ustekinumab]. MUC <= 6.2 at week 12 was the only independent predictor for MES <= 1 and MES=0 at reassessment (odds ratio [OR] 5.80, p=0.010; OR 10.41, p=0.041; respectively). MUC <= 6.2 at week 12 showed a negative predictive value of 96% for detecting MES=0. A >= 2 reduction of the MUC predicted MES=0 (area under the curve [AUC] 0.816). MUC <= 4.3 was the most accurate cut-off value for MES=0 [AUC 0.876]. Guyatt's responsiveness ratio for the MUC was 1.73 [>0.8]. Conclusion: MUC <= 6.2 at week 12 predicts long-term endoscopic response. MUC is accurate in monitoring treatment response and may be used in both clinical trials and routine practice.