P530 Early Intestinal Ultrasound changes to predict treatment response to anti-TNF therapy in paediatric Inflammatory Bowel Disease; a pilot study

Abstract

Abstract Background In paediatric Inflammatory Bowel Disease (IBD) selecting the right treatment in the early stages of disease is key to prevent disease progression and to prevent unnecessary exposure to ineffective treatment. Intestinal ultrasound (IUS) is increasingly used to monitor disease activity in response to therapy. However, little is known about the early transmural changes during anti-tumour necrosis factor (anti-TNF) therapy in paediatric IBD. The aim of this study is to assess the early changes in IUS parameters and to evaluate the very early predictive value of IUS for therapy response in paediatric IBD treated with anti-TNF-α therapy. Methods In this pilot study children (aged 3-18 years) starting with anti-TNF therapy (infliximab or adalimumab) were enrolled prospectively if ultrasound at baseline showed bowel wall thickness (BWT) ≥ 2,5mm. IUS was performed at baseline and the most affected bowel segment was identified. Subsequently IUS was repeated in this segment at week 2 and week 13. Response to therapy was determined at week 13. Response and remission was defined as follows. - Therapy response: a ≥50% decrease in faecal calprotectin (FCP) in combination with a decrease in PUCAI (≥20 points or normalisation) /PCDAI (≥12.5 points or normalisation), or normalisation of FCP (<250mg/kg)) - IUS response: decrease in BWT by 25% OR decrease in BWT by >2.0 mm of the most severely affected segment compared to baseline - IUS remission/Transmural healing: BWT<2.0 mm and no Doppler signal(Limberg score) and no mesenteric fat proliferation Results Eleven IBD patients (aged 7 to 12 years; 64% female) were enrolled. IUS response was observed in 5/11 patients at week 2 (decrease in BWT -25% in all). Doppler signal decreased in 3/11(one point in Limberg score in all). After 13 weeks 4/11 patients showed therapy response and 3/11 showed IUS remission. Conclusion Transmural changes were detected by IUS as early as 2 weeks after initiating anti-TNF therapy. This pilot study observed mainly reactivity in BWT, in contrast with previous studies that initially noted changes in Doppler signal. IUS has the potential to predict therapy response at an early stage. A larger sample size is needed to accurately assess its predictive value at week 2 for treatment response.