Prognostic Role of Post-Induction Fecal Calprotectin Levels in Patients with Inflammatory Bowel Disease Treated with Biological Therapies

Background: There is currently scarce knowledge about markers of early therapeutic response in patients with inflammatory bowel disease (IBD) treated with biologics. The aim of this study was to evaluate the role of fecal calprotectin (FC) as an early predictor of mucosal healing and clinical remission. Methods: Data from a multicenter series of 172 IBD patients treated with biologics between 2017 and 2020 were analyzed. Treatment outcomes were mucosal healing and clinical remission assessed at 2 years. FC levels were assessed at 14 weeks (post-induction), at 6 months, and yearly. The receiver operating characteristic (ROC) curve analysis was performed to calculate the best cut-off in % change of FC levels between post-induction and baseline predicting treatment outcomes. Sensitivity, specificity, and accuracy for several post-induction FC cut-off points were also calculated. Results: At 2 years, mucosal healing was noted in 77 patients (44.7%), of whom were 41 Crohn's disease (CD) and 36 ulcerative colitis (UC) patients, whereas 106 patients experienced clinical remission (61.6%), of whom were 59 CD and 47 UC patients. Both baseline and post-induction FC levels were significantly higher in non-responders as compared to responders. On the other hand, FC decrease was less pronounced in non-responders. Similar results were observed in all subgroups, namely according to disease (CD vs. UC), or treatment used (TNF-inhibitors vs. vedolizumab). The best cut-off points were -86% in % change in FC levels to predict mucosal healing and -83% for clinical remission. Conclusions: The current study suggests a predictive role of post-induction FC assessment to predict treatment response in IBD patients treated with biologics.