Prognostic Value of Fecal Calprotectin to Inform Treat-to-Target Monitoring in Ulcerative Colitis

We evaluated the value of post-induction fecal calprotectin (FCP) concentration as a biomarker in patients with ulcerative colitis (UC) treated with a biologic.This post hoc analysis of the GEMINI 1/GEMINI LTS (N = 620) and VARSITY (N = 771) trials evaluated the cross-sectional accuracy of post-induction FCP in identifying endoscopic activity and histologic inflammation, and the prognostic performance of FCP in identifying patients most likely to achieve endoscopic and histologic remission or require colectomy and UC-related hospitalization.The cross-sectional accuracy of FCP in identifying endoscopic activity and histologic inflammation was modest (63%-79%). However, a post-induction FCP concentration of ≤250 μg/g vs >250 μg/g was associated with a substantially higher probability of achieving clinical remission (odds ratio [OR], 4.03; 95% confidence interval [CI], 2.78-5.85), endoscopic remission (OR, 4.26; 95% CI, 2.83-6.40), and histologic remission (Robarts Histopathology Index: OR, 5.54; 95% CI, 3.77-8.14; Geboes grade: OR, 6.42; 95% CI, 4.02-10.26) at week 52 and a lower probability of colectomy over 7 years (hazard ratio, 0.296; 95% CI, 0.130-0.677) and UC-related hospitalization (hazard ratio, 0.583; 95% CI, 0.389-0.874). The association with colectomy was significant even among patients in symptomatic remission or with endoscopic improvement post-induction, and among patients with elevated FCP at baseline.Although FCP had only modest cross-sectional accuracy in identifying disease activity, an FCP concentration of ≤250 μg/g vs >250 μg/g was associated with increased probability of achieving long-term clinical, endoscopic, and histologic remission, and reduced probability of colectomy and UC-related hospitalization (ClinicalTrials.gov: NCT00783718, NCT00790933, NCT02497469).