EARLY INTESTINAL ULTRASOUND PREDICTS ENDOSCOPIC RESPONSE ON ANTI-INFLAMMATORY TREATMENT AND SHOWS DRUG-SPECIFIC RESPONSE TO BIOLOGICALS AND TOFACITINIB IN ULCERATIVE COLITIS

ABSTRACT

Introduction Objective evaluation of treatment response is the gold standard in ulcerative colitis (UC). In this setting, intestinal ultrasound (IUS) is a non-invasive alternative to endoscopy. Recent studies showed change in IUS parameters after treatment initiation but studies with an endoscopic reference standard are scarce. The aim of this study was to evaluate early change of IUS parameters and determine cut-off values for endoscopic endpoints in UC patients starting anti-inflammatory treatment. Methods In this longitudinal prospective study consecutive patients with moderate-severe UC (baseline endoscopic Mayo score (EMS)≥2) starting an anti-inflammatory treatment were included. Clinical scores, biochemical parameters and IUS parameters were collected at baseline, after 2 (T1), 6 (T2) and 8-26 weeks (T3) around time of the second sigmoidoscopy/colonoscopy. Bowel wall thickness (BWT), Colour Doppler signal (CDS), haustrations, inflammatory fat and wall layer stratification were measured as previously established1. Endoscopic remission (ER) and mucosal healing (MH) were evaluated in the sigmoid and defined as EMS=0 and EMS≤1, respectively. The ultrasonographist and endoscopist were blinded for the outcomes of endoscopy and IUS, respectively. Results 51 consecutive patients were included (Table 1) of whom 31 underwent a second endoscopy. Two additional patients underwent colectomy and were considered non-responders. 18 patients did not undergo second endoscopy due to the COVID-19 pandemic (n=2), refusal (n=5), loss to follow-up (n=1) or treatment escalation because of clinical deterioration confirmed by IUS and biomarkers before second endoscopy was performed (n=10). BWT was significantly lower from T2 onwards in patients reaching MH (p=0.026) and ER (p=0.002) at T3 (Fig 1). A significant decrease in BWT was already visible at T1 in patients receiving infliximab (median DBWT T0-T1 -26% [-43% - -6%], p=0.001) or tofacitinib (median ∆BWT T0-T1 -33% [-46% - -5%], p=0.001) but not in patients treated with vedolizumab (median ∆BWT T0-T1 -14% [-43% - 5%], p=0.11). Most accurate BWT cut-off values at T3 to determine MH and ER were 3.52 mm (AUROC 0.95, 95% CI 0.86-1.00, p<0.0001, sens91%, spec91%) and 2.98 mm (AUROC 0.94, 95% CI 0.85-1.00, p=0.001, sens87%, spec100%), respectively. At T2, BWT per 1 mm increase and CDS were inversely associated with MH (BWT OR 0.48 (0.24-0.96, p=0.038);CDS OR 0.16 (0.03-0.83), p=0.028) and ER (BWT OR 0.30 (0.11-0.76), p=0.01). Conclusion BWT and CDS 6 weeks after start of treatment could predict MH and ER. In addition, treatment response at IUS is drug-specific. Furthermore, we have provided accurate BWT cut-off values for endoscopic outcomes. In a point-of-care setting, (early) treatment evaluation with IUS could guide treatment decision in UC in order to optimize treatment response. 1. Bots et al. JCC 2021