P1126Early intestinal ultrasound transmural remission after infliximab induction predicts a non-complicated disease course in Crohn’s Disease

Abstract Background The ultimate goal in Crohn’s disease (CD) management is to modify the natural course of disease and prevent the development of bowel damage and complications over time. We aimed to assess the role of intestinal ultrasound (IUS) as a non-invasive predictor tool for long-term complicated disease. Methods Prospective longitudinal study including patients with active CD starting infliximab. IUS was performed at baseline, 3, 6 and 12 months of therapy. Patients were followed up until October 2025. The IBUS-SAS score (measuring bowel wall thickness (BWT), doppler, stratification (BWS), and inflammatory fat) was used to assess disease activity. IUS response was defined as reduction 25% in BWT. IUS remission was defined as the normalization of BWT (≤3mm), doppler sign (1), BWS, and inflammatory fat in the most affected segment or IBUS-SAS12. We defined a composite outcome for complicated disease including development of new stricturing or penetrating disease, need for intestinal surgery, hospitalization or switching therapy. Results We included 48 CD patients (48% male; mean age 36±13y). The median follow-up time was 58 months (IQR 50-70.75). During follow-up, 58% developed the composite outcome: 27% developed new stricturing disease; 23% needed hospitalization; 23% needed intestinal surgery; 23% needed to switch therapy; and 19% had new penetrating complications. Patients who developed the composite outcome during follow-up had more frequently B2/B3 phenotype at baseline (46% vs 10%, p = 0.019) and higher BWT at baseline (5.0mm (4.1-6.3) vs 4.4 (3.7-5.7); p = 0.043). Patients who developed complicated disease during follow-up had a significantly higher BWT and IBUS-SAS at all timepoints (Table 1). IUS remission and response at all timepoints were protective for the development of complicated disease (Table 1). All patients that achieved IUS remission at 3M (IBUS-SAS12) had a non-complicated clinical course (p 0.001) (Figure 1A). The best cut-off at 3M to predict complicated disease was IBUS-SAS 53.3 (AUC 0.781) and BWT 3.7mm (AUC 0.834). Patients who developed new stricturing disease were less likely to have IUS response at 6M (HR 0.17, 95% CI 0.04-0.64, p = 0.009) (Figure 1B). Conclusion Early ultrasound assessment provides valuable prognostic information in Crohn’s disease. Achieving transmural remission with IUS after infliximab induction strongly predicts a non-complicated clinical trajectory, supporting early treatment intensification to prevent later complications. Conflict of interest: Dr. Palmela, Carolina: Other: Consultancy fees from Biocodex, Faes Pharma, Tillots Pharma, Dr. Falk Pharma. Bárbara, André: No conflicts of interest Revés, Joana: None Morão, Bárbara: No conflict of interest Nascimento, Catarina: No conflict of interest Frias Gomes, Catarina: No conflict of interest Tinoco da Silva Torres, Joana: Grant: Abbvie, Janssen Personal Fees: Pfizer, Janssen, Abbvie, Sandoz, Lilly, Sanofi, Takeda Non-financial Support: Janssen, Abbvie