P734 Combining endoscopic and histological activity for predicting response to treatment. (25th January 2019) - Di Ruscio, M
Abstract: Background: Biological therapy (both anti-TNF and anti-integrins) currently represents the best treatment for moderate-to-severe ulcerative colitis (UC). Clinical trials and real life studies have reported their ability in achieving clinical, endoscopic and, recently, histological remission. However, about 60% of patients fail to achieve remission or failing to respond or have adverse events, so need 'switching'or 'swapping' strategies or surgery. It would be valuable to be able to predict which patients will respond to these drugs. Data regarding the predictive role of endoscopy and histology are scarce. Aim was to assess the role of endoscopy and histology in predicting response to biological drugs. Methods: We conducted a single-centre retrospective analysis on adult patients with moderate-to-severe active UC who underwent biological treatment, enrolling only patients with full endoscopic and histological assessment at baseline and at control time (at 48 weeks). Endoscopic and histological disease activity were assessed with the Mayo Endoscopic Subscore (MES) and the Nancy Histological Index (NHI), analysing the worst colonic segment. Clinical response to treatment was defined as a partial Mayo Score (PMS) < 2. Statistical analysis included Fisher exact test and Receiver-operator characteristic (ROC) curves (a p value less than 0.05 was considered significant). Results: Thirty adult patients referring to a single IBD Unit (Negrar Hospital) were enrolled. At baseline 63.3% (19/30) of patients were MES =3 while 36.7% (11/30) were MES=2. NHI was 4 in 60% (18/30) of patients, 3 in 33.3% (10/30) of patients and 2 in 6.7% (2/30) of patients. 46.7% (14/30) of patients were treated with Infliximab, 13.3% (4/30) with Adalimumab, 33.3% (10/30) with Golimumab and 6.7% (2/30) with Vedolizumab. At control time 30% (9/30) of patients achieved clinical remission, 26.3% (5/19) with MES=3 (of these, 4 with NHI=4 and 1 with NHI < 4) and 36.4% (4/11) with MES=2 (all with NHI < 4) at baseline. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of MES alone were 44.4%, 66.7%, 36.4% and 73.7%, respectively. The area under the ROC curve (AUROC) was 0.56. When MES=2 was analysed with NHI, sensitivity, specificity, PPV and NPV were 71.4%, 100%, 66.7% and 100%, respectively. The AUROC was 0.86. When MES=3 was analysed with NHI, sensitivity, specificity, PPV and NPV were 20%, 64.3%, 16.7% and 69.2%, respectively. The AUROC was 0.42. Conclusions: The combination of histology, evaluated using the NHI, and endoscopy, evaluated with MES, above all for moderate disease (MES), could identify patients who may not respond to biological treatment.