Reliability of MR Enterography Features for Describing Fibrostenosing Crohn Disease.

Background Clinical decision making and drug development for fibrostenosing Crohn disease is constrained by a lack of imaging definitions, scoring conventions, and validated end points. Purpose To assess the reliability of MR enterography features to describe Crohn disease strictures and determine correlation with stricture severity. Materials and Methods A retrospective study of patients with symptomatic terminal ileal Crohn disease strictures who underwent MR enterography at tertiary care centers (Cleveland Clinic: September 2013 to November 2020; Mayo Clinic: February 2008 to March 2019) was conducted by using convenience sampling. In the development phase, blinded and trained radiologists independently evaluated 26 MR enterography features from baseline and follow-up examinations performed more than 6 months apart, with no bowel resection performed between examinations. Follow-up examinations closest to 12 months after baseline were selected. Reliability was assessed using the intraclass correlation coefficient (ICC). In the validation phase, after five features were redefined, reliability was re-estimated in an independent convenience sample using baseline examinations. Multivariable linear regression analysis identified features with at least moderate interrater reliability (ICC ≥0.41) that were independently associated with stricture severity. Results Ninety-nine (mean age, 40 years ± 14 [SD]; 50 male) patients were included in the development group and 51 (mean age, 45 years ± 16 [SD]; 35 female) patients were included in the validation group. In the development group, nine features had at least moderate interrater reliability. One additional feature demonstrated moderate reliability in the validation group. Stricture length (ICC = 0.85 [95% CI: 0.75, 0.91] and 0.91 [95% CI: 0.75, 0.96] in development and validation phase, respectively) and maximal associated small bowel dilation (ICC = 0.74 [95% CI: 0.63, 0.80] and 0.73 [95% CI: 0.58, 0.87] in development and validation group, respectively) had the highest interrater reliability. Stricture length, maximal stricture wall thickness, and maximal associated small bowel dilation were independently (regression coefficients, 0.09-3.97; P < .001) associated with stricture severity. Conclusion MR enterography definitions and scoring conventions for reliably assessing features of Crohn disease strictures were developed and validated, and feature correlation with stricture severity was determined. © RSNA, 2024 Supplemental material is available for this article. See also the article by Rieder and Ma et al in this issue. See also the editorial by Galgano and Summerlin in this issue.

Systematic review: Defining, diagnosing and monitoring small bowel strictures in Crohn's disease on intestinal ultrasound.

BACKGROUND: Stricturing Crohn's disease (CD) occurs most commonly in the terminal ileum and poses a clinical problem. Cross-sectional imaging modalities such as intestinal ultrasound (IUS), computed tomography enterography (CTE), and magnetic resonance enterography (MRE) allow for assessment of the entire bowel wall and associated peri-enteric findings. Radiologic definitions of strictures have been developed for CTE and MRE; their reliability and responsiveness are being evaluated in index development programs. A comprehensive assessment strategy for strictures using IUS is needed. AIMS: To provide a detailed summary of definitions, diagnosis and monitoring of strictures on IUS as well as technical aspects of image acquisition. METHODS: We searched four databases up to 6 January 2024. Two-stage screening was done in duplicate. We assessed risk of bias using QUADAS-2. RESULTS: There were 56 studies eligible for inclusion. Definitions for strictures on IUS are heterogeneous, but the overall accuracy for diagnosis of strictures is high. The capability of IUS for characterising inflammation versus fibrosis in strictures is not accurate enough to be used in clinical practice or trials. We summarise definitions for improvement of strictures on IUS, and discuss parameters for image acquisition and standardisation. CONCLUSIONS: This systematic review is the first step for a structured program to develop a stricture IUS index for CD.

Reliability and Responsiveness of Histologic Indices for the Assessment of Crohn's Disease Activity.

BACKGROUND & AIMS: The operating properties of histologic indices for evaluating Crohn's disease (CD) activity are poorly characterized. We assessed the reliability and responsiveness of existing histologic indices/items used in CD and ulcerative colitis (UC), in addition to 3 novel items, and developed exploratory ileal, colonic, and colonic-ileal CD instruments. METHODS: Blinded central readers independently reviewed paired baseline and week 12 image sets from the EXTEND trial. Disease activity was scored using 4 indices (the Global Histologic Activity Score, Geboes Score, Nancy Histological Index, and Robarts Histopathology Index) and 3 items identified by an expert panel (mucin depletion, basal plasmacytosis, and ileal pyloric gland metaplasia). Reliability and responsiveness were quantified using the intraclass correlation coefficient (ICC) and area under the receiver operating curve (AUC), respectively. Exploratory indices were developed using backward stepwise linear regression analysis. Candidate independent variables were items with an inter-rater ICC ≥0.40 and AUC ≥0.56. The dependent variable was histologic disease activity measured by a 100-mm visual analogue scale. RESULTS: Paired image sets were available from 55 patients. Substantial to almost perfect inter-rater reliability (ICC, 0.63-0.87) and some responsiveness (AUC, 0.57-0.94) were observed for all existing indices regardless of whether individual colonic and ileal segments, combined colonic segments, or combined colonic and ileal segments were assessed and the calculation method used. Five items were tested as candidate items, and exploratory colonic, ileal, and colonic-ileal indices were developed. CONCLUSIONS: CD and UC indices were similarly reliable and responsive in measuring histologic CD activity. Exploratory index development did not offer benefit over current histologic instruments.

Use of external control arms in immune-mediated inflammatory diseases: a systematic review.

OBJECTIVES: External control arms (ECAs) provide useful comparisons in clinical trials when randomised control arms are limited or not feasible. We conducted a systematic review to summarise applications of ECAs in trials of immune-mediated inflammatory diseases (IMIDs). DESIGN: Systematic review with an appraisal of ECA source quality rated across five domains (data collection, study populations, outcome definitions, reliability and comprehensiveness of the dataset, and other potential limitations) as high, low or unclear quality. DATA SOURCES: Embase, Medline and Cochrane Central Register of Controlled Trial were searched through to 12 September 2023. ELIGIBILITY CRITERIA: Eligible studies were single-arm or randomised controlled trials (RCTs) of inflammatory bowel disease, pouchitis, rheumatoid arthritis, juvenile idiopathic arthritis, ankylosing spondylitis, psoriatic arthritis, psoriasis and atopic dermatitis in which an ECA was used as the comparator. DATA EXTRACTION AND SYNTHESIS: Two authors independently screened the search results in duplicate. The characteristics of included studies, external data source(s), outcomes and statistical methods were recorded, and the quality of the ECA data source was assessed by two independent authors. RESULTS: Forty-three studies met the inclusion criteria (inflammatory bowel disease: 16, pouchitis: 1, rheumatoid arthritis: 12, juvenile idiopathic arthritis: 1, ankylosing spondylitis: 5, psoriasis: 3, multiple indications: 4). The majority of these trials were single-arm (33/43) and enrolled adult patients (34/43). All included studies used a historical control rather than a contemporaneous ECA. In RCTs, ECAs were most often derived from the placebo arm of another RCT (6/10). In single-arm trials, historical case series were the most common ECA source (19/33). Most studies (31/43) did not employ a statistical approach to generate the ECA from historical data. CONCLUSIONS: Standardised ECA methodology and reporting conventions are lacking for IMIDs trials. The establishment of ECA reporting guidelines may enhance the rigour and transparency of future research.

Efficacy and Safety of IL-12/23 and IL-23 Inhibitors for Crohn's Disease: Systematic Review and Meta-Analysis.

BACKGROUND: Targeting interleukin-23 (IL-23) is an important therapeutic strategy for Crohn's disease (CD). AIMS: This systematic review and meta-analysis assessed the efficacy and safety of selective IL-23p19 and IL-12/23p40 inhibitors in patients with moderate-to-severe CD. METHODS: MEDLINE, Embase, and the Cochrane library (CENTRAL) were searched from inception to May 24, 2023, for randomized, placebo- or active comparator-controlled induction and/or maintenance trials of selective IL-23p19 and IL-12/23p40 inhibitors in pediatric and adult patients with CD. The primary outcome was the proportion of patients in clinical remission. Secondary outcomes were clinical response, endoscopic remission, endoscopic response, and safety. Data were pooled using a random-effects model. Risk of bias and certainty of evidence were assessed using the Cochrane risk of bias tool and the GRADE criteria, respectively. RESULTS: Eighteen trials (n = 5561) were included. Most studies were rated as low risk of bias. Targeting IL-23 was significantly superior to placebo for inducing clinical (risk ratio [RR] = 1.87, 95% confidence interval [CI] 1.58-2.21) and endoscopic (RR = 3.20, 95%CI 2.17-4.70) remission and maintaining clinical remission (RR = 1.39, 95%CI 1.10-1.77) (GRADE high certainty evidence for all outcomes). Subgroup analysis showed that targeting IL-23 was superior to placebo for inducing clinical remission in biologic-naïve (RR = 2.20, 95%CI 1.46-3.32, I2 = 0%, p = 0.39) and biologic-experienced patients (RR = 1.82, 95%CI 1.27-2.60, I2 = 56.5%, p = 0.01). Targeting IL-23 was associated with a decreased risk of serious adverse events in induction (RR = 0.55, 95%CI 0.44-0.73) and maintenance (RR = 0.72, 95%CI 0.53-0.98) trials compared to placebo (high certainty evidence). CONCLUSION: Targeting IL-23 is effective and safe for inducing and maintaining clinical and endoscopic remission in patients with moderate-to-severe CD.

Efficacy and Safety of Advanced Oral Small Molecules for Inflammatory Bowel Disease: Systematic Review and Meta-Analysis.

BACKGROUND AND AIMS: Oral small-molecule drugs [SMDs] are expanding the therapeutic landscape for inflammatory bowel disease [IBD]. This systematic review and meta-analysis summarizes the efficacy and safety of JAK inhibitor [JAKi] and sphingosine-1-phosphate [S1P] receptor modulator treatments for ulcerative colitis [UC] and Crohn's disease [CD]. METHODS: MEDLINE, Embase, and CENTRAL were searched from inception to May 30, 2022. Randomized controlled trials [RCTs] of JAKi and S1P receptor modulators in adults with UC or CD were eligible. Clinical, endoscopic, histological, and safety data were pooled and analysed using a random-effects model. RESULTS: Thirty-five RCTs [26 UC, nine CD] were included. In UC, JAKi therapy was associated with induction of clinical (risk ratio [RR] 3.16, 95% confidence interval [CI] 2.03-4.92; I2 = 65%) and endoscopic [RR 3.99, 95% CI 2.36-6.75; I2 = 36%] remission compared to placebo. Upadacitinib was associated with histological response [RR 2.63, 95% CI 1.97-3.53]. S1P modulator therapy was associated with induction of clinical [RR 2.52, 95% CI 1.88-3.39; I2 = 1%] and endoscopic [RR 2.39, 95% CI 1.07-5.33; I2 = 0%] remission relative to placebo. Ozanimod was superior to placebo for inducing histological remission in UC [RR 2.20, 95% CI 1.43-3.37; I2 = 0%], while etrasimod was not [RR 2.36, 95% CI 0.71-7.88; I2 = 0%]. In CD, JAKi therapy was superior to placebo for induction of clinical remission [RR 1.53, 95% CI 1.19-1.98; I2 = 31%], and endoscopic remission [RR 4.78, 95% CI 1.63-14.06; I2 = 43%] compared to placebo. The risk of serious infections was similar for oral SMDs and placebo. CONCLUSION: JAKi and S1P receptor modulator therapies are effective in IBD for inducing clinical and endoscopic remission and, in some circumstances, histological response.

CORE-IBD: A Multidisciplinary International Consensus Initiative to Develop a Core Outcome Set for Randomized Controlled Trials in Inflammatory Bowel Disease.

BACKGROUND & AIMS: End points to determine the efficacy and safety of medical therapies for Crohn's disease (CD) and ulcerative colitis (UC) are evolving. Given the heterogeneity in current outcome measures, harmonizing end points in a core outcome set for randomized controlled trials is a priority for drug development in inflammatory bowel disease. METHODS: Candidate outcome domains and outcome measures were generated from systematic literature reviews and patient engagement surveys and interviews. An iterative Delphi process was conducted to establish consensus: panelists anonymously voted on items using a 9-point Likert scale, and feedback was incorporated between rounds to refine statements. Consensus meetings were held to ratify the outcome domains and core outcome measures. Stakeholders were recruited internationally, and included gastroenterologists, colorectal surgeons, methodologists, and clinical trialists. RESULTS: A total of 235 patients and 53 experts participated. Patient-reported outcomes, quality of life, endoscopy, biomarkers, and safety were considered core domains; histopathology was an additional domain for UC. In CD, there was consensus to use the 2-item patient-reported outcome (ie, abdominal pain and stool frequency), Crohn's Disease Activity Index, Simple Endoscopic Score for Crohn's Disease, C-reactive protein, fecal calprotectin, and co-primary end points of symptomatic remission and endoscopic response. In UC, there was consensus to use the 9-point Mayo Clinic Score, fecal urgency, Robarts Histopathology Index or Geboes Score, fecal calprotectin, and a composite primary end point including both symptomatic and endoscopic remission. Safety outcomes should be reported using the Medical Dictionary for Regulatory Activities. CONCLUSIONS: This multidisciplinary collaboration involving patients and clinical experts has produced the first core outcome set that can be applied to randomized controlled trials of CD and UC.

Clinical, Endoscopic, and Safety Placebo Rates in Induction and Maintenance Trials of Crohn's Disease: Meta-Analysis of Randomised Controlled Trials.

BACKGROUND: Precision in estimating placebo rates is important for clinical trial design. AIM: To quantify placebo rates across relevant endpoints in Crohn's disease [CD] trials and identify the factors influencing these rates in a contemporary meta-analysis. METHODS: We searched MEDLINE, EMBASE, and CENTRAL from inception to March 2021. Eligible studies were placebo-controlled trials of pharmacological interventions for CD. Placebo response and remission rates for induction and maintenance trials were extracted and pooled by random-effects to quantify placebo rates across studies. Mixed-effects meta-regression was used to evaluate the effects of study-level characteristics on placebo rates. RESULTS: In 125 studies [91 induction, 46 maintenance], placebo clinical remission and response rates for induction studies were 18% (95% confidence interval [CI] 16, 21%], and 32% [95% CI 29, 35%], respectively, and for maintenance studies were 28% [95% CI 23, 34%] and 30% [95% CI 24, 37%], respectively. Endoscopic remission and response rates in induction studies were 8% [95% CI 4, 18%] and 16% [95% CI 11, 23%], respectively. Trials enrolling patients with prior biologic exposure, longer disease duration, and higher CD activity index scores were associated with lower placebo clinical remission rates. Increased duration of follow-up, more follow-up visits, and a greater proportion of patients with colonic disease distribution were associated with higher clinical placebo rates. CONCLUSIONS: Placebo remission and response rates in CD trials vary according to the phase of the trial, endpoint assessed, and induction or maintenance design. These contemporary estimates will help to inform future CD trial design.

Increased Risk of Infections with Anti-TNF Agents in Patients with Crohn's Disease After Elective Surgery: Meta-Analysis.

BACKGROUND: Postoperative complication rates in patients with inflammatory bowel disease (IBD) receiving preoperative biologics have been analyzed without considering the surgical context. Emergency surgery may be associated with an increased risk of infectious complications, compared to elective operations. AIMS: To conduct a systematic review and meta-analysis investigating the relationship between preoperative biologic therapy and postoperative outcomes in Crohn's disease (CD) and ulcerative colitis (UC), focusing on elective surgery. METHODS: Electronic databases were searched up to February 12, 2020, for studies of patients with IBD undergoing elective abdominal surgery receiving biologic therapy within 3 months before surgery compared to no therapy, or another biologic therapy. Certainty of evidence was evaluated using GRADE. The primary outcomes were the rate of infections and total complications within 30 days. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were calculated. RESULTS: Thirty-three studies were included. Preoperative treatment with anti-tumor necrosis factor (TNF) therapy in patients with CD undergoing elective surgery was associated with increased odds of infection (OR 2.05; 95% CI 1.40-3.01), but not total complications (OR 1.03; 95% CI 0.71-1.51). In elective surgery for UC, preoperative anti-TNF therapy was not associated with infectious (OR 1.03; 95% CI 0.34-3.07) or total complications (OR 0.67; 95% CI 0.29-1.58). Limited data indicate that emergency surgery did not significantly affect the rate of complications. CONCLUSIONS: Anti-TNF therapy prior to elective surgery may increase the odds of postoperative infection in CD, although the certainty of evidence is very low. More evidence is needed, particularly for newer biologics.

International consensus to standardise histopathological scoring for small bowel strictures in Crohn's disease.

OBJECTIVE: Effective medical therapy and validated trial outcomes are lacking for small bowel Crohn's disease (CD) strictures. Histopathology of surgically resected specimens is the gold standard for correlation with imaging techniques. However, no validated histopathological scoring systems are currently available for small bowel stricturing disease. We convened an expert panel to evaluate the appropriateness of histopathology scoring systems and items generated based on panel opinion. DESIGN: Modified RAND/University of California Los Angeles methodology was used to determine the appropriateness of 313 candidate items related to assessment of CD small bowel strictures. RESULTS: In this exercise, diagnosis of naïve and anastomotic strictures required increased bowel wall thickness, decreased luminal diameter or internal circumference, and fibrosis of the submucosa. Specific definitions for stricture features and technical sampling parameters were also identified. Histopathologically, a stricture was defined as increased thickness of all layers of the bowel wall, fibrosis of the submucosa and bowel wall, and muscularisation of the submucosa. Active mucosal inflammatory disease was defined as neutrophilic inflammation in the lamina propria and any crypt or intact surface epithelium, erosion, ulcer and fistula. Chronic mucosal inflammatory disease was defined as crypt architectural distortion and loss, pyloric gland metaplasia, Paneth cell hyperplasia, basal lymphoplasmacytosis, plasmacytosis and fibrosis, or prominent lymphoid aggregates at the mucosa/submucosa interface. None of the scoring systems used to assess CD strictures were considered appropriate for clinical trials. CONCLUSION: Standardised assessment of gross pathology and histopathology of CD small bowel strictures will improve clinical trial efficiency and aid drug development.

Disease Activity Indices for Pouchitis: A Systematic Review.

BACKGROUND: Several indices exist to measure pouchitis disease activity; however, none are fully validated. As an initial step toward creating a validated instrument, we identified pouchitis disease activity indices, examined their operating properties, and assessed their value as outcome measures in clinical trials. METHODS: Electronic databases were searched to identify randomized controlled trials including indices that evaluated clinical, endoscopic, or histologic pouchitis disease activity. A second search identified studies that assessed the operating properties of pouchitis indices. RESULTS: Eighteen randomized controlled trials utilizing 4 composite pouchitis disease activity indices were identified. The Pouchitis Disease Activity Index (PDAI) was most commonly used (12 of 18; 66.7%) to define both trial eligibility (8 of 12; 66.7%), and outcome measures (12 of 12; 100%). In a separate search, 21 studies evaluated the operating properties of 3 pouchitis indices; 90.5% (19 of 21) evaluated validity, of which 42.1% (8 of 19) evaluated the construct validity of the PDAI. Criterion validity (73.7%; 14 of 19) was evaluated through correlation of the PDAI with fecal calprotectin (FCP; r = 0.188 to 0.71), fecal lactoferrin (r = 0.570 to 0.582), and C-reactive protein (CRP; r = 0.584). Two studies assessed correlation of the modified PDAI (mPDAI) with FCP (r = 0.476 and r = 0.565, respectively). Fair to moderate inter-rater reliability of the PDAI (k = 0.440) and mPDAI (k = 0.389) was reported in a single study. Responsiveness of the PDAI pre-antibiotic and postantibiotic treatment was partially evaluated in a single study of 12 patients. CONCLUSIONS: Development and validation of a specific pouchitis disease activity index is needed given that existing instruments are not valid, reliable, or responsive.

Modeling Endoscopic Improvement after Induction Treatment With Mesalamine in Patients With Mild-to-Moderate Ulcerative Colitis.

BACKGROUND & AIMS: Endoscopic improvement is an important treatment target for mild-to-moderate ulcerative colitis (UC). However, early endoscopic evaluation is not always feasible. We aimed to develop a clinical decision support tool to discriminate patients who have achieved endoscopic improvement from those with more severe inflammation following mesalamine induction therapy. METHODS: We performed a post-hoc analysis of data from a phase 3 non-inferiority trial of 726 adults with mild-to-moderate UC treated with mesalamine. Multivariable logistic regression modeling determined associations between candidate variables and endoscopic improvement (Mayo endoscopic subscore=0-1 according to blinded central reading) at Week 8. Internal model validation was performed using bootstrap resampling. A clinical decision support tool was developed to stratify patients into low, intermediate, and high probability groups for endoscopic improvement. RESULTS: Variables associated with endoscopic improvement at Week 8 included 50% reduction in fecal calprotectin from baseline (odds ratio [OR] 2.64, 95% CI:, 1.81, 3.85), reduction in rectal bleeding (OR 1.79 per point reduction, 95% CI: 1.35, 2.39), and improvement in physician global assessment (OR 2.32 per point improvement, 95% CI: 1.88, 2.85). The baseline Geboes score (OR 0.74 per grade, 95% CI: 0.65, 0.85) and prolonged disease duration (OR 0.95 per year, 95% CI: 0.92, 0.98) were negatively associated with endoscopic improvement. This model strongly discriminated endoscopic improvement in the development dataset (area under the curve [AUC] 0.84, 95% CI: 0.81, 0.87) and during validation (AUC 0.83). CONCLUSIONS: We developed and validated a clinical decision support tool that has good discriminative performance for induction of endoscopic improvement in patients with mild-to-moderate UC treated with mesalamine. ClinicalTrials.gov Registration: NCT01903252.

Anti-Drug Antibody Formation Against Biologic Agents in Inflammatory Bowel Disease: A Systematic Review and Meta-Analysis.

BACKGROUND AND AIMS: Immunogenicity with formation of anti-drug antibodies (ADA) to biologics is an important reason for treatment failure in inflammatory bowel disease (IBD). Our aim was to assess the rate of ADA, the effect of combination therapy with immunomodulators on ADA and the influence of ADA on efficacy and safety of biologics for IBD treatment. METHODS: MEDLINE, Embase and Cochrane Central Register of Controlled Trials (CENTRAL) were searched from inception to April 2020 for trials of biologics that assessed immunogenicity. The overall certainty of evidence was evaluated using Grading of Recommendations, Assessment, Development and Evaluations (GRADE). The primary outcome was rate of ADA. Secondary outcomes included efficacy and safety outcomes among patients with detectable versus undetectable ADA. For dichotomous outcomes, pooled risk ratios (RR) and 95% confidence intervals (CI) were calculated. RESULTS: Data from 68 studies were analyzed and 33 studies (5850 patients) were included in the meta-analysis. Pooled ADA rates for biologic monotherapy were 28.0% for infliximab, 7.5% for adalimumab, 3.8% for golimumab, 10.9% for certolizumab, 6.2% for ustekinumab and 16.0% for natalizumab. Pooled ADA rates were 8.4% for vedolizumab and 5.0% for etrolizumab for combo- and monotherapy combined. In all biologics, ADA rates were underestimated by use of drug-sensitive ADA assays and higher dose and/or frequency. ADA rate was significantly reduced in patients treated with combination therapy for infliximab (RR 0.52; 95% CI 0.44-0.62), adalimumab (RR 0.31; 95% CI 0.14-0.69), golimumab (RR 0.29; 95% CI 0.10-0.83), certolizumab pegol (RR 0.30; 95% CI 0.14-0.67) and natalizumab (RR 0.20; 95% CI 0.11-0. 39). ADA to infliximab were associated with lower clinical response rates (RR 0.75; 95% CI 0.61-0.91) and higher rates of infusion reactions (RR 2.36; 95% CI 1.85-3.01). CONCLUSIONS: Differences in analytical methods to detect ADA hamper comparison of true ADA rates across biologics in IBD. Use of combination therapy with immunomodulators appeared to reduce ADA positivity for most biologics. For infliximab, ADA were associated with reduced drug efficacy and increased adverse events.

An International Consensus to Standardize Integration of Histopathology in Ulcerative Colitis Clinical Trials.

BACKGROUND & AIMS: Histopathology is an emerging treatment target in ulcerative colitis (UC) clinical trials. Our aim was to provide guidance on standardizing biopsy collection protocols, identifying optimal evaluative indices, and defining thresholds for histologic response and remission after treatment. METHODS: An international, interdisciplinary expert panel of 19 gastroenterologists and gastrointestinal pathologists was assembled. A modified RAND/University of California, Los Angeles appropriateness methodology was used to address relevant issues. A total of 138 statements were derived from a systematic review of the literature and expert opinion. Each statement was anonymously rated as appropriate, uncertain, or inappropriate using a 9-point scale. Survey results were reviewed and discussed before a second round of voting. RESULTS: Histologic measurements collected using a uniform biopsy strategy are important for assessing disease activity and determining therapeutic efficacy in UC clinical trials. Multiple biopsy strategies were deemed acceptable, including segmental biopsies collected according to the endoscopic appearance. Biopsies should be scored for architectural change, lamina propria chronic inflammation, basal plasmacytosis, lamina propria and epithelial neutrophils, epithelial damage, and erosions/ulcerations. The Geboes score, Robarts Histopathology Index, and Nancy Index were considered appropriate for assessing histologic activity; use of the modified Riley score and Harpaz Index were uncertain. Histologic activity at baseline should be required for enrollment, recognizing this carries operational implications. Achievement of histologic improvement or remission was considered an appropriate and realistic therapeutic target. Current histologic indices require validation for pediatric populations. CONCLUSIONS: These recommendations provide a framework for standardized implementation of histopathology in UC trials. Additional work is required to address operational considerations and areas of uncertainty.

Standardisation of intestinal ultrasound scoring in clinical trials for luminal Crohn's disease.

BACKGROUND: Intestinal ultrasound (IUS) is a valuable tool for assessment of Crohn's disease (CD). However, there is no widely accepted luminal disease activity index. AIMS: To identify appropriate IUS protocols, indices, items, and scoring methods for measurement of luminal CD activity and integration of IUS in CD clinical trials. METHODS: An expert international panel of adult and paediatric gastroenterologists (n = 15) and radiologists (n = 3) rated the appropriateness of 120 statements derived from literature review and expert opinion (scale of 1-9) using modified RAND/UCLA methodology. Median panel scores of 1 to ≤3.5, >3.5 to <6.5 and ≥6.5 to 9 were considered inappropriate, uncertain and appropriate ratings respectively. The statement list and survey results were discussed prior to voting. RESULTS: A total of 91 statements were rated appropriate with agreement after two rounds of voting. Items considered appropriate measures of disease activity were bowel wall thickness (BWT), vascularity, stratification and mesenteric inflammatory fat. There was uncertainty if any of the existing IUS disease activity indices were appropriate for use in CD clinical trials. Appropriate trial applications for IUS included patient recruitment qualification when diseased segments cannot be adequately assessed by ileocolonoscopy and screening for exclusionary complications. At outcome assessment, remission endpoints including BWT and vascularity, with or without mesenteric inflammatory fat, were considered appropriate. Components of an ideal IUS disease activity index were identified based upon panel discussions. CONCLUSIONS: The panel identified appropriate component items and applications of IUS for CD clinical trials. Empiric evidence, and development and validation of an IUS disease activity index are needed.

An expert consensus to standardise the assessment of histological disease activity in Crohn's disease clinical trials.

BACKGROUND: Targeting histological remission or response in Crohn's disease (CD) is not recommended in clinical practice guidelines or as an outcome in clinical trials due to uncertainties regarding index validity and prognostic relevance. AIMS: To conduct a modified RAND/University of California Los Angeles appropriateness process with the goal of producing a framework to standardise histological assessment of CD activity in clinical trials. METHODS: A total of 115 statements generated from literature review and expert opinion were rated on a scale of 1-9 by a panel of 11 histopathologists and 6 gastroenterologists. Statements were classified as inappropriate, uncertain or appropriate based upon the median panel rating and degree of disagreement. RESULTS: The panellists considered it important to measure histological activity in clinical trials to determine efficacy and that absence of neutrophilic inflammation is an appropriate histological target. They were uncertain whether the Global Histological Activity Score was an appropriate instrument for measuring histological activity. The Geboes Score and Robarts Histopathology Index were considered appropriate. Two biopsies from five segments should be biopsied, and the colon and the ileum should be analysed separately for all indices. Endoscopic mucosal appearance should guide biopsy procurement site with biopsies taken from the ulcer edge, or the most macroscopically inflamed area in the absence of ulcers. CONCLUSION: We evaluated the appropriateness of items for assessing histological disease activity in CD clinical trials. These items will be used to develop a novel histological index.

Systematic Review: Gastrointestinal Ultrasound Scoring Indices for Inflammatory Bowel Disease.

BACKGROUND AND AIMS: Serial measurements of luminal disease activity may facilitate inflammatory bowel disease management. Gastrointestinal ultrasound is an easily performed, non-invasive alternative to other assessment modes. However, its widespread use is limited by concerns regarding validity, reliability, and responsiveness. We systematically identified ultrasound scoring indices used to evaluate inflammatory bowel disease activity and examine their operating characteristics. METHODS: Electronic databases were searched from inception to June 14, 2019 using pre-defined terms. Studies that reported on gastrointestinal ultrasound index operating properties in an inflammatory bowel disease population were eligible for inclusion. Study characteristics, index components, and operating property data [ie, validity, reliability, responsiveness, sensitivity, specificity, accuracy, positive predictive value, and negative predictive value] were extracted. The QUADAS-2 tool was used to examine study-level risk of bias. RESULTS: Of the 2610 studies identified, 26 studies reporting on 21 ultrasound indices were included. The most common index components included bowel wall thickness, colour Doppler imaging, and bowel wall stratification. The correlation between ultrasound indices and references standards ranged r = 0.62-0.95 and k = 0.40-0.96. Sensitivity, specificity, accuracy, positive predictive value, and negative predictive values ranged 39-100%, 63-100%, 73-100%, 57-100%, and 40-100%, respectively. Reliability and responsiveness data were limited. Most [92%, 24/26] studies received at least one unclear or high risk of bias rating. CONCLUSIONS: Several gastrointestinal ultrasound indices for use in inflammatory bowel disease have been developed. Future research should focus on fully validating existing or novel gastrointestinal ultrasound scoring instruments for assessment of Crohn's disease and ulcerative colitis.

Clinical Trials of IL-12/IL-23 Inhibitors in Inflammatory Bowel Disease.

The inflammatory bowel diseases (IBDs) are chronic immune-mediated inflammatory disorders, including ulcerative colitis (UC) and Crohn's disease (CD). IBD results from a complex interplay between environmental, microbial, and genetic factors to create an abnormal immunological response leading to intestinal inflammation. Many pathways driving inflammation have been described, and different pathways may predominate in an individual patient. The interleukin (IL)-23 pathway plays a key role in IBD pathogenesis through promoting a pathological Th17 response. Targeting IL-23 is effective in the treatment of IBD. Ustekinumab, a monoclonal antibody targeting the shared p40 subunit of IL-12/23, is approved for treatment of moderate-to-severe CD and UC. Specific IL-23p19 antagonists are in development and promising results from phase II trials of mirikizumab and risankizumab underscore the potential for this class of treatment. In this review, we summarize the mechanisms of action and the evidence from clinical trials supporting the efficacy and safety of different IL-23 antagonists for IBD.

Evaluating the optimum number of biopsies to assess histological inflammation in ulcerative colitis: a retrospective cohort study.

BACKGROUND: The optimal ulcerative colitis biopsy protocol is unclear. AIM: To evaluate the number of biopsies required to accurately assess microscopic disease activity in ulcerative colitis METHODS: Biopsies from patients with ≥4 rectosigmoid samples, and clinical and endoscopic data, were retrospectively obtained from a prospective biobank. Histology and endoscopic videos were read blindly. A 4-biopsy Robarts Histopathology Index (RHI) reference score, consisting of the worst item-level ratings from four biopsies, was compared to 1-, 2- and 3-biopsy estimates. Agreement was determined using bivariate errors-in-variable regression analysis (acceptance interval: ±8.25). Endoscopic activity and disease location subgroup analyses were also performed. RESULTS: Forty-six patients had ≥4 rectosigmoid biopsies available (N = 287). The 2-biopsy (tolerance interval: -7.66, 4.79) and 3-biopsy (tolerance interval: -4.86, 3.46) RHI scores demonstrated acceptable agreement with 4-biopsy scores. One-biopsy scores demonstrated unacceptable agreement (tolerance interval: -13.99, 7.78). Mean RHI scores using the 2-, 3- and 4-biopsy approaches were similar (6.1 ± 9.6 P = 0.36; 6.8 ± 10.5, P = 0.7; 7.5 ± 11.2), whereas the 1-biopsy estimate was lower (4.4 ± 8.1, P = 0.06). Histological remission rates were identical for the 2-, 3- and 4-biopsy methods (65.2%, P = 1.0). Subgroup analysis demonstrated that three biopsies were required in patients with endoscopically active disease. Sampling additional colonic locations yielded lower histological remission rates compared to rectosigmoid sampling alone (33.3% vs 61.9%, P = 0.1). CONCLUSIONS: A minimum of two - conservatively, three - biopsies are required to reliably assess disease activity in a single colonic segment using the RHI. Further studies are needed of endoscopically active patients and sampling locations. These results have implications for biopsy strategies in clinical trials and practice.

Oral 5-aminosalicylic acid for maintenance of remission in ulcerative colitis.

BACKGROUND: Oral 5-aminosalicylic acid (5-ASA; also known as mesalazine or mesalamine) preparations were intended to avoid the adverse effects of sulfasalazine (SASP) while maintaining its therapeutic benefits. In an earlier version of this review, we found that 5-ASA drugs were more effective than placebo for maintenance of remission of ulcerative colitis (UC), but had a significant therapeutic inferiority relative to SASP. In this version, we have rerun the search to bring the review up to date. OBJECTIVES: To assess the efficacy, dose-responsiveness, and safety of oral 5-ASA compared to placebo, SASP, or 5-ASA comparators for maintenance of remission in quiescent UC and to compare the efficacy and safety of once-daily dosing of oral 5-ASA with conventional (two or three times daily) dosing regimens. SEARCH METHODS: We performed a literature search for studies on 11 June 2019 using MEDLINE, Embase, and the Cochrane Library. In addition, we searched review articles and conference proceedings. SELECTION CRITERIA: We included randomized controlled trials with a minimum treatment duration of six months. We considered studies of oral 5-ASA therapy for treatment of participants with quiescent UC compared with placebo, SASP, or other 5-ASA formulations. We also included studies that compared once-daily 5-ASA treatment with conventional dosing of 5-ASA and 5-ASA dose-ranging studies. DATA COLLECTION AND ANALYSIS: We used standard methodological procedures expected by Cochrane. The primary outcome was the failure to maintain clinical or endoscopic remission. Secondary outcomes were adherence, adverse events (AE), serious adverse events (SAE), withdrawals due to AEs, and withdrawals or exclusions after entry. Trials were separated into five comparison groups: 5-ASA versus placebo, 5-ASA versus SASP, once-daily dosing versus conventional dosing, 5-ASA (balsalazide, Pentasa, and olsalazine) versus comparator 5-ASA formulation (Asacol and Salofalk), and 5-ASA dose-ranging. We calculated the risk ratio (RR) and 95% confidence interval (CI) for each outcome. We analyzed data on an intention-to-treat basis, and used GRADE to assess the overall certainty of the evidence. MAIN RESULTS: The search identified 44 studies (9967 participants). Most studies were at low risk of bias. Ten studies were at high risk of bias. Seven of these studies were single-blind and three were open-label. 5-ASA is more effective than placebo for maintenance of clinical or endoscopic remission. About 37% (335/907) of 5-ASA participants relapsed at six to 12 months compared to 55% (355/648) of placebo participants (RR 0.68, 95% CI 0.61 to 0.76; 8 studies, 1555 participants; high-certainty evidence). Adherence to study medication was not reported for this comparison. SAEs were reported in 1% (6/550) of participants in the 5-ASA group compared to 2% (5/276) of participants in the placebo group at six to 12 months (RR 0.60, 95% CI 0.19 to 1.84; 3 studies, 826 participants; low-certainty evidence). There is probably little or no difference in AEs at six to 12 months' follow-up (RR 0.93, 95% CI 0.73 to 1.18; 5 studies, 1132 participants; moderate-certainty evidence). SASP is more effective than 5-ASA for maintenance of remission. About 48% (416/871) of 5-ASA participants relapsed at six to 18 months compared to 43% (336/784) of SASP participants (RR 1.14, 95% CI 1.03 to 1.27; 12 studies, 1655 participants; high-certainty evidence). Adherence to study medication and SAEs were not reported for this comparison. There is probably little or no difference in AEs at six to 12 months' follow-up (RR 1.07, 95% CI 0.82 to 1.40; 7 studies, 1138 participants; moderate-certainty evidence). There is little or no difference in clinical or endoscopic remission rates between once-daily and conventionally dosed 5-ASA. About 37% (717/1939) of once-daily participants relapsed over 12 months compared to 39% (770/1971) of conventional-dosing participants (RR 0.94, 95% CI 0.88 to 1.01; 10 studies, 3910 participants; high-certainty evidence). There is probably little or no difference in medication adherence rates. About 10% (106/1152) of participants in the once-daily group failed to adhere to their medication regimen compared to 8% (84/1154) of participants in the conventional-dosing group (RR 1.18, 95% CI 0.72 to 1.93; 9 studies, 2306 participants; moderate-certainty evidence). About 3% (41/1587) of participants in the once-daily group experienced a SAE compared to 2% (35/1609) of participants in the conventional-dose group at six to 12 months (RR 1.20, 95% CI 0.77 to 1.87; moderate-certainty evidence). There is little or no difference in the incidence of AEs at six to 13 months' follow-up (RR 0.98, 95% CI 0.92 to 1.04; 8 studies, 3497 participants; high-certainty evidence). There may be little or no difference in the efficacy of different 5-ASA formulations. About 44% (158/358) of participants in the 5-ASA group relapsed at six to 18 months compared to 41% (142/349) of participants in the 5-ASA comparator group (RR 1.08, 95% CI 0.91 to 1.28; 6 studies, 707 participants; low-certainty evidence). AUTHORS' CONCLUSIONS: There is high-certainty evidence that 5-ASA is superior to placebo for maintenance therapy in UC. There is high-certainty evidence that 5-ASA is inferior compared to SASP. There is probably little or no difference between 5-ASA and placebo, and 5-ASA and SASP in commonly reported AEs such as flatulence, abdominal pain, nausea, diarrhea, headache, and dyspepsia. Oral 5-ASA administered once daily has a similar benefit and harm profile as conventional dosing for maintenance of remission in quiescent UC.