Kinetics of Intestinal Ultrasound and Shear-wave Elastography to assess early response in Ulcerative Colitis Patients Treated with Filgotinib

Abstract Background and Aims A reduction of bowel wall thickness (BWT) on intestinal ultrasound (IUS) predicts endoscopic response in ulcerative colitis (UC). Advanced techniques like shear-wave elastography (SWE), might enhance response assessment. We aimed to identify early IUS parameters to predict treatment response to filgotinib in UC. Methods This prospective observational study included UC patients with endoscopically active disease (endoscopic Mayo score (EMS) ≥2, extending beyond the rectum) starting on filgotinib. IUS parameters, including SWE, were assessed at baseline (T0), week 4 (T1) and at second endoscopy (T2). EMS of both the most-affected segment and the sigmoid was assessed at T0 and T2, endoscopic response was defined ≥1 point decrease in EMS. Results A total of 23 patients were included. Six of 21 patients who underwent a second endoscopy were endoscopic responders. At T1 in the sigmoid, a BWT decrease of ≥ 1.33 mm or ≥ 24.7% (OR 32.5 [2.4-443.2], p = 0.009 and OR: 13.8 [1.2-156.6], p = 0.035) and submucosa decrease of ≥ 20.8% (OR: 13.8 [1.2-156.6], p = 0.035) predicted endoscopic response. Additionally, Colour Doppler Signal (CDS) improvement at T1 predicted endoscopic response (OR: 20.0 [1.7-241.7], p = 0.018). In the sigmoid, SWE values changed differently over time between responders and non-responders (T2: 9.9 ± 15.7 vs. -8.1 ± 11.4 kPa, p = 0.002). However, SWE values at T1 were not predictive of endoscopic response (OR: 1.07 [0.99-1.16], p = 0.088). Conclusions On IUS, BWT, submucosal thickness and CDS predict endoscopic response after four weeks of filgotinib treatment. SWE values in the sigmoid differ between responders and non-responders, but early assessment does not predict treatment response.