P355 Exceeding treatment expectations in Crohn’s disease: transmural healing and a new definition of deep remission

Abstract Background While mucosal (MH) and transmural healing (TH) predict relevant clinical outcomes in Crohn’s disease (CD), little is known about the real significance and clinical impact of deep remission (DR). The aim of this study was to better explore the concept of DR, towards a direct correlation between MH, TH and biomarkers. Methods A real-world observational longitudinal study was performed to evaluate the rate of clinical remission (CR), MH and TH, and the fecal calprotectin (FC)/C-reactive protein (CRP) levels in all consecutive patients with CD undergoing maintenance treatment with biologics. A ROC curve was constructed to define the best FC and CRP cut-offs associated with MH and TH. Finally, CD patients achieving CR, MH and TH, in association with the target FC and CRP values, were considered in DR. Results Among, 118 CD patients, CR, MH and TH were achieved in, 74 (62.7%), 52 (44.1%) and, 38 patients (32.2%), respectively. After, 2 years, the mean FC levels decreased from, 494 ±, 515.4 μg/gr to, 260 ±, 354.9 μg/gr (p<0.01). Using the ROC curve analysis, a FC cut-off value of, 94 μg/gr was associated with both MH (sensitivity, 94.2%, specificity, 84.8%, PPV, 83.05%, NPV, 94.92%, AUC, 0.95) and TH (sensitivity, 92.1%, specificity, 70%, PPV, 64.4%, NPV, 94.9%, AUC, 0.88). The MH/FC and TH/FC k of agreement was, 0.81 (p<0.01) and, 0.58 (p<0.01), respectively. CRP <, 5 mg/L was associated with both MH (sensitivity, 96.1%, specificity, 62.1%, PPV, 66.7%, NPV, 95.35%, AUC, 0.85) and TH (sensitivity, 97.4%, specificity, 52.5%, PPV, 52%, NPV, 95.35%, AUC, 0.78). When considering CD patients with concomitant CR, MH and TH associated with a FC level <, 94 μg/gr and CRP <, 5 mg/L, DR was identified in, 33 patients (27.9%). Conclusion A FC cut-off of, 94 μg/gr and a normal CRP could be included in the definition of DR in association with CR, MH and TH. Thus, DR can be achieved in approximately, 30% of CD patients during maintenance treatment with biologics.