Noninvasive tests to measure endoscopic activity in patients with Crohn's disease (CD) have limitations. We aimed to develop a test to identify patients in remission, based on endoscopic analysis, and monitor CD activity based on serum levels of proteins. We developed a test to measure 13 proteins in blood (ANG1, ANG2, CRP, SAA1, IL7, EMMPRIN, MMP1, MMP2, MMP3, MMP9, TGFA, CEACAM1, and VCAM1), called the endoscopic healing index [EHI], using samples from 278 patients with CD from a multinational training cohort. We validated the test using 2 independent cohorts of patients with CD: 116 biologic-naive patients with early-stage CD (validation cohort 1) and 195 biologic-exposed patients with chronic CD (validation cohort 2). The ability of the test to identify patients with active disease vs patients in remission (defined as a simple endoscopic score for CD of ≤2 and ≤1 in each segment, or a total CD endoscopic index of severity score <3) was assessed by using area under receiver operating characteristic curve (AUROC) analysis. The diagnostic accuracy of the test was compared with that of measurement of serum C-reactive protein (CRP) and fecal calprotectin. The EHI scores range from 0 to 100 units; higher scores indicate more severe CD activity, based on endoscopy findings. The EHI identified patients in remission with an AUROC of 0.962 in validation cohort 1 (95% confidence interval, 0.942-0.982) and an AUROC of 0.693 in validation cohort 2 (95% confidence interval, 0.619-0.767), regardless of CD location or phenotype. A cutoff value of 20 points identified patients in remission with the highest level of sensitivity (97.1% in validation cohort 1 and 83.2% in validation cohort 2), with specificity values of 69.0% and 36.6%, respectively. A cutoff value of 50 points identified patients in remission with the highest level of specificity (100% in validation cohort 1 and 87.8% in validation cohort 2), with sensitivity values of 37.3% and 30.0%, respectively. The EHI identified patients in remission with a significantly higher AUROC value than the test for CRP (0.876, P < .001 in validation cohort 1 and 0.624, P = .109 in validation cohort 2). In analysis of patients with available FC measurements, the AUROC value for the EHI did not differ significantly from that of measurement of FC (AUROC, 0.950 for EHI vs AUROC, 0.923 for FC; P = .147 in validation cohort 1 and AUROC, 0.803 for EHI vs AUROC, 0.854 for FC; P = .298 in validation cohort 2). We developed an index called the EHI to identify patients with CD in endoscopic remission based on blood levels of 13 proteins. The EHI identified patients with resolution of endoscopic disease activity, with good overall accuracy, although with variation between the 2 cohorts assessed. The EHI AUROC values were comparable to measurement of FC and higher than measurement of serum CRP. The test might be used in practice to assess endoscopic activity in patients with CD.

The goal of therapeutic drug monitoring (TDM) is to optimize anti-TNF (tumor necrosis factor) biologic treatment in patients with inflammatory bowel disease (IBD). Although commercial assays are readily available for both ustekinumab and vedolizumab, the use of TDM with these newer biologic medications is at its infancy. The clinical utility of TDM with non-anti-TNF mechanisms of action is not clear. This review summarizes the latest available data on the pharmacokinetics of newer biologic and oral small molecules and highlights the threshold concentrations that have been associated with improved outcomes in IBD patients.

INTRODUCTION: Ulcerative colitis (UC) is a chronic condition that may require long-term treatment. We report the final efficacy and safety results of the UNIFI long-term extension study of ustekinumab in patients with UC through 4 years. METHODS: Ustekinumab induction responders who completed 44 weeks of maintenance treatment and agreed to enter the long-term extension continued their subcutaneous maintenance therapy (90 mg ustekinumab every 8 or 12 weeks [q8w or q12w] or placebo). Starting at week 56, randomized patients could receive dose adjustment to 90 mg q8w. Symptoms and adverse events were assessed through the study; endoscopic assessment was conducted at week 200. RESULTS: Of the 348 patients randomized to subcutaneous ustekinumab at maintenance baseline (q8w and q12w combined), 55.2% were in symptomatic remission at week 200. A greater proportion of biologic-naive patients (67.2% [117/174]) were in symptomatic remission than those with a history of biologic failure (41.6% [67/161]). Among patients in symptomatic remission at week 200, 96.4% were corticosteroid-free. Of the 171 patients with endoscopic evaluation at week 200, 81.6% (71/87) in the q12w group and 79.8% (67/84) in the q8w group had endoscopic improvement. From weeks 156 to the final safety visit (up to week 220), no deaths, major adverse cardiovascular events, or tuberculosis occurred in patients receiving ustekinumab. Nasopharyngitis, UC worsening, and upper respiratory tract infections were the most frequently reported adverse events. DISCUSSION: The long-term efficacy of ustekinumab maintenance in patients with UC was confirmed through 4 years. No new safety signals were observed. ClinicalTrials.gov number NCT02407236.