Analysis of Clinical Trial Screen Failures in Inflammatory Bowel Diseases [IBD]: Real World Results from the International Organization for the study of IBD

BACKGROUND

Recruitment for randomized controlled trials [RCTs] in inflammatory bowel diseases [IBD] has substantially dropped over time. This study aimed to assess reasons why IBD patients are not included in sponsored multicentre phase IIb-III RCTs.

METHODS

All IOIBD members [n = 58] were invited to participate. We divided barriers to participation as follows: [1] reasons patients with active IBD were not deemed appropriate for an RCT; [2] reasons qualified patients did not wish to participate; and [3] reasons for screen failure [SF] in patients agreeing to participate. We assess these in a 4-week prospective study including, consecutively, all patients with symptomatic disease for whom a treatment change was required. In addition, we performed a 6-month retrospective study to further evaluate reasons for SF.

RESULTS

A total of 106 patients (60 male [56.6%], 63 Crohn's disease [CD] [59.4%]), from ten centres across the world, were included in the prospective study. An RCT has not been proposed to 65 of them [mainly due to eligibility criteria]. Of the 41 patients to whom an RCT was offered, eight refused [mainly due to reluctance to receive placebo] and 28 agreed to participate. Among these 28 patients, five failed their screening and 23 were finally included in an RCT. A total of 107 patients (61 male [57%], 67 CD [62.6%]), from 13 centres worldwide, were included in our retrospective study of SFs. The main reason was insufficient disease activity.

CONCLUSION

This first multicentre study analysing reasons for non-enrolment in IBD RCTs shows that we lose patients at each step. Eligibility criteria, the risk of placebo assignment, and insufficient disease activity were part of the main barriers.

Clinical Predictors of Early and Late Endoscopic Recurrence Following Ileocolonic Resection in Crohn's Disease

BACKGROUND AND AIMS

Multiple factors are suggested to place Crohn's disease patients at risk of recurrence after ileocolic resection with conflicting associations. We aimed to identify clinical predictors of recurrence at first [early] and further [late] postoperative colonoscopy.

METHODS

Crohn's disease patients undergoing ileocolic resection were prospectively recruited at six North American centres. Clinical data were collected and endoscopic recurrence was defined as Rutgeerts score ≥i2. A multivariable model was fitted to analyse variables independently associated with recurrence.

RESULTS

A total of 365 patients undergoing 674 postoperative colonoscopies were included with a median age of 32 years, 189 [51.8%] were male, and 37 [10.1%] were non-Whites. Postoperatively, 133 [36.4%] used anti-tumour necrosis factor [anti-TNF] and 30 [8.2%] were smokers. At first colonoscopy, 109 [29.9%] had recurrence. Male gender (odds ratio [OR] = 1.95, 95% confidence interval [CI] 1.12-3.40), non-White ethnicity [OR = 2.48, 95% CI 1.09-5.63], longer interval between surgery and colonoscopy [OR = 1.09, 95% CI 1.002-1.18], and postoperative smoking [OR = 2.78, 95% CI 1.16-6.67] were associated with recurrence, while prophylactic anti-TNF reduced the risk [OR = 0.28, 95% CI 0.14-0.55]. Postoperative anti-TNF prophylaxis had a protective effect on anti-TNF experienced patients but not on anti-TNF naïve patients. Among patients without recurrence at first colonoscopy, Rutgeerts score i1 was associated with subsequent recurrence [OR = 4.43, 95% CI 1.73-11.35].

CONCLUSIONS

We identified independent clinical predictors of early and late Crohn's disease postoperative endoscopic recurrence. Clinical factors traditionally used for risk stratification failed to predict recurrence and need to be revised.

When Should I Get My Next COVID Vaccine? Data from the SUrveillance of responses to COVID-19 vaCcines in systEmic immunE mediated inflammatory Diseases (SUCCEED)study

OBJECTIVE

To determine how serologic responses to COVID vaccination/infection in immunemediated inflammatory disease (IMID) are affected by time since last vaccination and other factors.

METHODS

Post-COVID-19 vaccination, data and dried blood spots/sera were collected from adults with rheumatoid arthritis, inflammatory bowel disease, systemic lupus, ankylosing spondylitis/spondylarthritis and psoriasis/psoriatic arthritis. First sample was at enrolment and then 2-4 weeks and 3, 6, and 12 months after latest vaccine dose. Multivariate generalized estimating equation regressions (including medications, demographics, and vaccination history) evaluated serologic response, based on log-transformed anti-RBD IgG titres; we also measured anti-nucleocapsid IgG.

RESULTS

Positive associations for log-transformed anti-RBD titres were seen with female sex, number of doses, and self-reported COVID infections in 2021-2023. Negative associations were seen with prednisone, anti-TNF agents, and rituximab.Over 2021-2023, most (94%) of anti-nucleocapsid positivity was associated with a self-reported infection in the 3 months prior. From March 2021 to Feb 2022, anti-nucleocapsid positivity was present in 5-15% of samples and was highest in the post-Omicron era, with anti-nucleocapsid positivity trending to 30-35% or higher as of March 2023. Anti-nucleocapsid positivity in IMID remained lower than Canada's general population seroprevalence (>50% in 2022 and >75% in 2023).Time since last vaccination was negatively associated with log-transformed anti-RBD titres, particularly after 210 days.

CONCLUSION

Ours is the first pan-Canadian IMID assessment of how vaccine history and other factors affect serologic COVID-19 vaccine responses. These findings may help individuals personalize vaccination decisions, including consideration of additional vaccination when >6 months has elapsed since last COVID vaccination/infection.

Interobserver agreement of current and new proposed endoscopic scores for postoperative recurrence in Crohn's disease

BACKGROUND AND AIMS

The modified Rutgeerts' score (mRS) is widely used for the assessment of endoscopic postoperative recurrence (ePOR) in Crohn's disease (CD) after ileocolic resection to guide therapeutic decisions. To improve the validity and prognostic value of this endoscopic assessment, two new scores have been proposed. This study assessed the interobserver agreement of the current (mRS) and new endoscopic scores for ePOR in CD.

METHODS

Sixteen Dutch academic and non-academic IBD specialists assessed endoscopic videos (n=71) of postoperative CD patients (n=66) retrieved from nine Dutch centers. Each video was assessed for the degree of inflammation by four gastroenterologists using the mRS and the new proposed endoscopic score: REMIND score (separate score of anastomosis and neoterminal ileum) and updated Rutgeerts score (assessment of lesions at the anastomotic line, ileal inlet, ileal body and neoterminal ileum). In addition, lesions at the ileal body, ileal inlet, neoterminal ileum, colonic and/or ileal blind loop were separately assessed. Interobserver agreement was assessed using Fleiss' weighted kappa.

RESULTS

Fleiss' weighted kappa for the mRS was 0.67 (95% confidence interval [CI] 0.59-0.74). The weighted kappa for the REMIND score was 0.73 (95% CI 0.65-0.80) for lesions in the neoterminal ileum and 0.46 (95% CI 0.35-0.58) for anastomotic lesions. The weighted kappa for the updated Rutgeerts' score was 0.69 (95% CI 0.62-0.77). The weighted kappa for lesions in the ileal body, ileal inlet, neoterminal ileum, colonic and ileal blind loop was 0.61 (95% CI 0.49-0.73), 0.63 (95% CI 0.54-0.72), 0.61 (95% CI 0.49-0.74), 0.83 (95% CI 0.62-1.00) and 0.68 (95% CI 0.46-0.89).

CONCLUSION

The interobserver agreement of the mRS is substantial. Similarly, the interobserver agreement is substantial for the updated Rutgeerts' score. According to the REMIND score, the interobserver agreement was substantial for lesions in the neoterminal ileum, whereas only moderate for anastomotic lesions. Since therapeutic decisions in clinical practice are based on these assessments and these scores are used as outcome measure in clinical studies, further improvement of the interobserver agreement is essential.

Determining the optimal treatment target in patients with ulcerative colitis: rationale, design, protocol and interim analysis for the randomised controlled VERDICT trial

INTRODUCTION

Symptoms, endoscopy and histology have been proposed as therapeutic targets in ulcerative colitis (UC). Observational studies suggest that the achievement of histologic remission may be associated with a lower risk of complications, compared with the achievement of endoscopic remission alone. The actiVE ulcerative colitis, a RanDomIsed Controlled Trial (VERDICT) aims to determine the optimal treatment target in patients with UC.

METHODS AND ANALYSIS

In this multicentre, prospective randomised study, 660 patients with moderate to severe UC (Mayo rectal bleeding subscore [RBS] ≥1; Mayo endoscopic score [MES] ≥2) are randomly assigned to three treatment targets: corticosteroid-free symptomatic remission (Mayo RBS=0) (group 1); corticosteroid-free endoscopic remission (MES ≤1) and symptomatic remission (group 2); or corticosteroid-free histologic remission (Geboes score <2B.0), endoscopic remission and symptomatic remission (group 3). Treatment is escalated using vedolizumab according to a treatment algorithm that is dependent on the patient's baseline UC therapy until the target is achieved at weeks 16, 32 or 48. The primary outcome, the time from target achievement to a UC-related complication, will be compared between groups 1 and 3 using a Cox proportional hazards model.

ETHICS AND DISSEMINATION

The study was approved by ethics committees at the country level or at individual sites as per individual country requirements. A full list of ethics committees is available on request. Study results will be disseminated in peer-reviewed journals and at scientific meetings.

TRIAL REGISTRATION NUMBER

EudraCT: 2019-002485-12; NCT04259138.

Biomarkers That Predict Crohn's Disease Outcomes

Crohn's disease (CD), a chronic inflammatory condition of the digestive tract, poses significant challenges in terms of disease prognosis and treatment selection. Biomarkers have the potential to predict CD outcomes and guide clinical decision-making. This review aims to summarize the current literature on promising biomarkers associated with CD outcomes and their potential clinical implications. The identification of reliable biomarkers for CD outcomes is of paramount importance in tailoring treatment strategies, monitoring disease activity, and predicting the risk of complications. Clinical prognostic factors traditionally used to assess disease severity, and the likelihood of complications have limitations in accuracy and predictive value. Thus, there is a need for more precise biomarkers, particularly in newly diagnosed and treatment-naive patients. Pharmacogenomic markers, such as TPMT and NUDT15 polymorphisms, have been utilized to identify patients at risk of adverse events with thiopurine therapy. Several biomarkers, including HLA haplotypes, oncostatin M expression, and transcriptomic profiles, have shown associations with response to anti-TNF therapy. Confocal laser endomicroscopy and single-cell analyses hold promise in predicting treatment response to specific therapies. The identification of biomarkers associated with post-operative recurrence in CD is crucial, as it could lead to changes in management algorithms. Several promising microbiome signatures and proteomic profiles have been identified. In conclusion, biomarkers have the potential to revolutionize the management of CD by providing valuable prognostic information and guiding treatment decisions. However, further research and validation are necessary to establish their clinical utility and integration into routine practice.

Geography Influences Susceptibility to SARS-CoV-2 Serological Response in Patients With Inflammatory Bowel Disease: Multinational Analysis From the ICARUS-IBD Consortium

BACKGROUND

Beyond systematic reviews and meta-analyses, there have been no direct studies of serological response to COVID-19 in patients with inflammatory bowel disease (IBD) across continents. In particular, there has been limited data from Asia, with no data reported from India. The ICARUS-IBD (International study of COVID-19 Antibody Response Under Sustained immunosuppression in IBD) consortium assessed serological response to SARS-CoV-2 in patients with IBD in North America, Europe, and Asia.

METHODS

The ICARUS-IBD study is a multicenter observational cohort study spanning sites in 7 countries. We report seroprevalence data from 2303 patients with IBD before COVID-19 vaccination between May 2020 and November 2021. SARS-CoV-2 anti-spike and anti-nucleocapsid antibodies were analyzed.

RESULTS

The highest and lowest SARS-CoV-2 anti-spike seropositivity rates were found in Asia (81.2% in Chandigarh and 57.9% in Delhi, India; and 0% in Hong Kong). By multivariable analysis, country (India: odds ratio [OR], 18.01; 95% confidence interval [CI], 12.03-26.95; P < .0001; United Kingdom: OR, 2.43; 95% CI, 1.58-3.72; P < .0001; United States: OR, 2.21; 95% CI, 1.27-3.85; P = .005), male sex (OR, 1.46; 95% CI, 1.07-1.99; P = .016), and diabetes (OR, 2.37; 95% CI, 1.04-5.46; P = .039) conferred higher seropositivity rates. Biological therapies associated with lower seroprevalence (OR, 0.22; 95% CI, 0.15-0.33; P < .0001). Multiple linear regression showed associations between anti-spike and anti-nucleocapsid titers with medications (P < .0001) but not with country (P = .3841).

CONCLUSIONS

While the effects of medications on anti-SARS-CoV-2 antibody titers in patients with IBD were consistent across sites, geographical location conferred the highest risk of susceptibility to serologically detectable SARS-CoV-2 infection. Over half of IBD patients in India were seropositive prior to vaccination. These insights can help to inform shielding advice, therapeutic choices, and vaccine strategies in IBD patients for COVID-19 and future viral challenges.

Genetic coding variant in complement factor B (CFB) is associated with increased risk for perianal Crohn's disease and leads to impaired CFB cleavage and phagocytosis

OBJECTIVE

Perianal Crohn's disease (pCD) occurs in up to 40% of patients with CD and is associated with poor quality of life, limited treatment responses and poorly understood aetiology. We performed a genetic association study comparing CD subjects with and without perianal disease and subsequently performed functional follow-up studies for a pCD associated SNP in Complement Factor B (CFB).

DESIGN

Immunochip-based meta-analysis on 4056 pCD and 11 088 patients with CD from three independent cohorts was performed. Serological and clinical variables were analysed by regression analyses. Risk allele of rs4151651 was introduced into human CFB plasmid by site-directed mutagenesis. Binding of recombinant G252 or S252 CFB to C3b and its cleavage was determined in cell-free assays. Macrophage phagocytosis in presence of recombinant CFB or serum from CFB risk, or protective CD or healthy subjects was assessed by flow cytometry.

RESULTS

Perianal complications were associated with colonic involvement, OmpC and ASCA serology, and serology quartile sum score. We identified a genetic association for pCD (rs4151651), a non-synonymous SNP (G252S) in CFB, in all three cohorts. Recombinant S252 CFB had reduced binding to C3b, its cleavage was impaired, and complement-driven phagocytosis and cytokine secretion were reduced compared with G252 CFB. Serine 252 generates a de novo glycosylation site in CFB. Serum from homozygous risk patients displayed significantly decreased macrophage phagocytosis compared with non-risk serum.

CONCLUSION

pCD-associated rs4151651 in CFB is a loss-of-function mutation that impairs its cleavage, activation of alternative complement pathway, and pathogen phagocytosis thus implicating the alternative complement pathway and CFB in pCD aetiology.

Gut Microbiome Composition Is Associated With Future Onset of Crohn's Disease in Healthy First-Degree Relatives

BACKGROUND & AIMS

The cause of Crohn's disease (CD) is unknown, but the current hypothesis is that microbial or environmental factors induce gut inflammation in genetically susceptible individuals, leading to chronic intestinal inflammation. Case-control studies of patients with CD have cataloged alterations in the gut microbiome composition; however, these studies fail to distinguish whether the altered gut microbiome composition is associated with initiation of CD or is the result of inflammation or drug treatment.

METHODS

In this prospective cohort study, 3483 healthy first-degree relatives (FDRs) of patients with CD were recruited to identify the gut microbiome composition that precedes the onset of CD and to what extent this composition predicts the risk of developing CD. We applied a machine learning approach to the analysis of the gut microbiome composition (based on 16S ribosomal RNA sequencing) to define a microbial signature that associates with future development of CD. The performance of the model was assessed in an independent validation cohort.

RESULTS

In the validation cohort, the microbiome risk score (MRS) model yielded a hazard ratio of 2.24 (95% confidence interval, 1.03-4.84; P = .04), using the median of the MRS from the discovery cohort as the threshold. The MRS demonstrated a temporal validity by capturing individuals that developed CD up to 5 years before disease onset (area under the curve > 0.65). The 5 most important taxa contributing to the MRS included Ruminococcus torques, Blautia, Colidextribacter, an uncultured genus-level group from Oscillospiraceae, and Roseburia.

CONCLUSION

This study is the first to demonstrate that gut microbiome composition is associated with future onset of CD and suggests that gut microbiome is a contributor in the pathogenesis of CD.

The chromatin and single-cell transcriptional landscapes of CD4 T cells in inflammatory bowel disease link risk loci with a proinflammatory Th17 cell population

Introduction

The imbalance between Th17 and regulatory T cells in inflammatory bowel diseases (IBD) promotes intestinal epithelial cell damage. In this scenario, T helper cell lineage commitment is accompanied by dynamic changes to the chromatin that facilitate or repress gene expression.

Methods

Here, we characterized the chromatin landscape and heterogeneity of intestinal and peripheral CD4 T cellsfrom IBD patients using in house ATAC-Seq and single cell RNA-Seq libraries.

Results

We show that chromatin accessibility profiles of CD4 T cells from inflamed intestinal biopsies relate to genes associated with a network of inflammatory processes. After integrating the chromatin profiles of tissue-derived CD4 T cells and in-vitro polarized CD4 T cell subpopulations, we found that the chromatin accessibility changes of CD4 T cells were associated with a higher predominance of pathogenic Th17 cells (pTh17 cells) in inflamed biopsies. In addition, IBD risk loci in CD4 T cells were colocalized with accessible chromatin changes near pTh17-related genes, as shown in intronic STAT3 and IL23R regions enriched in areas of active intestinal inflammation. Moreover, single cell RNA-Seq analysis revealed a population of pTh17 cells that co-expresses Th1 and cytotoxic transcriptional programs associated with IBD severity.

Discussion

Altogether, we show that cytotoxic pTh17 cells were specifically associated with IBD genetic variants and linked to intestinal inflammation of IBD patients.

Third and Fourth Vaccine Doses Broaden and Prolong Immunity to SARS-CoV-2 in Adult Patients with Immune-Mediated Inflammatory Diseases

Previous studies have reported impaired humoral responses after SARS-CoV-2 mRNA vaccination in patients with immune-mediated inflammatory diseases (IMIDs), particularly those treated with anti-TNF biologics. We previously reported that IMID patients diagnosed with inflammatory bowel disease, psoriasis, psoriatic arthritis, ankylosing spondylitis, or rheumatoid arthritis exhibited greater waning of Ab and T cell responses than healthy control subjects after SARS-CoV-2 vaccine dose 2. Fewer data are available on the effects of third and fourth doses. This observational cohort study collected plasma and PBMCs from healthy control subjects and untreated or treated patients with IMIDs prevaccination and after one to four doses of SARS-CoV-2 mRNA vaccine (BNT162b2 or mRNA-1273). SARS-CoV-2-specific Ab levels, neutralization, and T cell cytokine release were measured against wild-type and Omicron BA.1 and BA.5 variants of concern. Third vaccine doses substantially restored and prolonged Ab and T cell responses in patients with IMIDs and broadened responses against variants of concern. Fourth-dose effects were subtle but also prolonged Ab responses. However, patients with IMIDs treated with anti-TNF, especially patients with inflammatory bowel disease, exhibited lower Ab responses even after the fourth dose. Although T cell IFN-γ responses were maximal after one dose, IL-2 and IL-4 production increased with successive doses, and early production of these cytokines was predictive of neutralization responses at 3-4 mo postvaccination. Our study demonstrates that third and fourth doses of the SARS-CoV-2 mRNA vaccines sustain and broaden immune responses to SARS-CoV-2, supporting the recommendation for three- and four-dose vaccination regimens in patients with IMIDs.

Identifying high-impact variants and genes in exomes of Ashkenazi Jewish inflammatory bowel disease patients

Inflammatory bowel disease (IBD) is a group of chronic digestive tract inflammatory conditions whose genetic etiology is still poorly understood. The incidence of IBD is particularly high among Ashkenazi Jews. Here, we identify 8 novel and plausible IBD-causing genes from the exomes of 4453 genetically identified Ashkenazi Jewish IBD cases (1734) and controls (2719). Various biological pathway analyses are performed, along with bulk and single-cell RNA sequencing, to demonstrate the likely physiological relatedness of the novel genes to IBD. Importantly, we demonstrate that the rare and high impact genetic architecture of Ashkenazi Jewish adult IBD displays significant overlap with very early onset-IBD genetics. Moreover, by performing biobank phenome-wide analyses, we find that IBD genes have pleiotropic effects that involve other immune responses. Finally, we show that polygenic risk score analyses based on genome-wide high impact variants have high power to predict IBD susceptibility.

Vedolizumab for the Treatment of Chronic Pouchitis

BACKGROUND

Approximately half the patients with ulcerative colitis who undergo restorative proctocolectomy with ileal pouch-anal anastomosis (IPAA) will subsequently have pouchitis, and among those patients, one fifth will have chronic pouchitis.

METHODS

We conducted a phase 4, double-blind, randomized trial to evaluate vedolizumab in adult patients in whom chronic pouchitis had developed after undergoing IPAA for ulcerative colitis. Patients were assigned (in a 1:1 ratio) to receive vedolizumab intravenously at a dose of 300 mg or placebo on day 1 and at weeks 2, 6, 14, 22, and 30. All the patients received concomitant ciprofloxacin from weeks 1 to 4. The primary end point was modified Pouchitis Disease Activity Index (mPDAI)-defined remission (an mPDAI score of ≤4 and a reduction from baseline of ≥2 points in the mPDAI total score; scores range from 0 to 12, with higher scores indicating more severe pouchitis) at week 14. The mPDAI is based on clinical symptoms and endoscopic findings. Other efficacy end points included mPDAI-defined remission at week 34, mPDAI-defined response (a reduction from baseline of ≥2 points in the mPDAI score) at weeks 14 and 34, and PDAI-defined remission (a PDAI score of ≤6 and a reduction from baseline of ≥3 points; scores range from 0 to 18, with higher scores indicating more severe pouchitis) at weeks 14 and 34. The PDAI is based on clinical symptoms, endoscopic findings, and histologic findings.

RESULTS

Among the 102 patients who underwent randomization, the incidence of mPDAI-defined remission at week 14 was 31% (16 of 51 patients) with vedolizumab and 10% (5 of 51 patients) with placebo (difference, 21 percentage points; 95% confidence interval [CI], 5 to 38; P = 0.01). Differences in favor of vedolizumab over placebo were also seen with respect to mPDAI-defined remission at week 34 (difference, 17 percentage points; 95% CI, 0 to 35), mPDAI-defined response at week 14 (difference, 30 percentage points; 95% CI, 8 to 48) and at week 34 (difference, 22 percentage points; 95% CI, 2 to 40), and PDAI-defined remission at week 14 (difference, 25 percentage points; 95% CI, 8 to 41) and at week 34 (difference, 19 percentage points; 95% CI, 2 to 37). Serious adverse events occurred in 3 of 51 patients (6%) in the vedolizumab group and in 4 of 51 patients (8%) in the placebo group.

CONCLUSIONS

Treatment with vedolizumab was more effective than placebo in inducing remission in patients who had chronic pouchitis after undergoing IPAA for ulcerative colitis. (Funded by Takeda; EARNEST ClinicalTrials.gov number, NCT02790138; EudraCT number, 2015-003472-78.).

A181 HIGHER CUMULATIVE HISTOLOGIC INFLAMMATORY BURDEN SCORE IS ASSOCIATED WITH THE RISK OF DEVELOPMENT OF COLORECTAL NEOPLASIA IN ULCERATIVE COLITIS

Background

Ulcerative colitis (UC) patients have an elevated risk of colorectal neoplasia (CRN). Younger age at diagnosis, extent of colitis, and longer duration of colitis, as well as increased severity, which is a component of the cumulative inflammatory burden score (CIB), have been associated with the development of CRN. CIB was developed based on a large cohort of UC patients from St. Mark’s Hospital (UK) but needs further validation in independent cohorts.

Purpose

We analyzed the association between higher histologic CIB and development of CRN in longstanding UC patients.

Method

A matched case-control cohort of UC patients with at least 8 years of disease duration was analyzed at Mount Sinai Hospital. Patients with primary sclerosing cholangitis were excluded. Cases consisted of UC patients with colitis-associated neoplasia defined as indefinite for dysplasia (IND), low-grade dysplasia (LGD), high-grade dysplasia (HGD), or colorectal cancer (CRC). Each case was matched to two controls by age at disease onset, disease duration, and histological extent of colitis. Histologic reports obtained by colonoscopy were reviewed and histological activity was assessed as quiescent/normal (0), mild (1), moderate (2), and severe (3). The colonic area with the higher score was utilized and the CIB was calculated by summing each score and multiplying it by the interval of surveillance. A mean CIB (mCIB) was also calculated for each patient dividing the CIB by the number of colonoscopies. Continuous variables including CIB scores and mCIB scores were summarized as median and interquartile range (IQR) and differences between groups were compared by Mann-Whitney test.

Result(s)

Fifty-four UC patients were analyzed with 18 having CRN (6 CRC, 2 HGD, 3 LGD and 7 IND) and 36 controls without CRN. The clinical characteristics of the total cohort, cases and controls are depicted in the Table. Median age at last colonoscopy assessed was 45 years (36-55) and 40.7% were female. The median age at onset of UC was 23 years (19-37) and median duration of UC was 16 years (11-23). All patients had extensive histologic colonic disease. There were no differences between cases and controls in interval of surveillance evaluated (7.5 vs 7.8 years, p = 0.7) and median number of colonoscopies with histologic assessment (4 vs 4, p =0.6). Cases with CRN had significantly higher CIB (11.4 vs 7.9, p = 0.02) and mCIB (2.9 vs 2.0, p = 0.02) compared to controls.

Image

Conclusion(s)

The histologic CIB score is associated with an increased risk of developing CRN in UC patients with similar age at onset of disease, disease duration and colitis extent. Given CIB reflects the severity of histologic inflammation over the years, treatment strategies to improve histologic inflammation could reduce the incidence of CRN in UC.

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Disclosure of Interest

None Declared

Immune response and barrier dysfunction-related proteomic signatures in preclinical phase of Crohn's disease highlight earliest events of pathogenesis

OBJECTIVE

The measure of serum proteome in the preclinical state of Crohn's disease (CD) may provide insight into biological pathways involved in CD pathogenesis. We aimed to assess associations of serum proteins with future CD onset and with other biomarkers predicting CD risk in a healthy at-risk cohort.

DESIGN

In a nested case-control study within the Crohn's and Colitis Canada Genetics Environment Microbial Project (CCC-GEM) cohort, which prospectively follows healthy first-degree relatives (FDRs), subjects who developed CD (n=71) were matched with four FDRs remaining healthy (n=284). Using samples at recruitment, serum protein profiles using the Olink Proximity Extension Assay platform was assessed for association with future development of CD and with other baseline biomarkers as follows: serum antimicrobial antibodies (AS: positive antibody sum) (Prometheus); faecal calprotectin (FCP); gut barrier function using the fractional excretion of lactulose-to-mannitol ratio (LMR) assay.

RESULTS

We identified 25 of 446 serum proteins significantly associated with future development of CD. C-X-C motif chemokine 9 (CXCL9) had the highest OR with future risk of CD (OR=2.07 per SD, 95% CI 1.58 to 2.73, q=7.9e-5), whereas matrix extracellular phosphoglycoprotein had the lowest OR (OR 0.44, 95% CI 0.29 to 0.66, q=0.02). Notably, CXCL9 was the only analyte significantly associated with all other CD-risk biomarkers with consistent direction of effect (FCP: OR=2.21; LMR: OR=1.67; AS: OR=1.59) (q<0.05 for all).

CONCLUSION

We identified serum proteomic signatures associated with future CD development, reflecting potential early biological processes of immune and barrier dysfunction.

Existing Bowel Preparation Quality Scales Are Reliable in the Setting of Centralized Endoscopy Reading

BACKGROUND

Development of bowel preparation products has been based upon colon cleansing rating by a local endoscopist. It is unclear how bowel preparation scales perform when centrally evaluated.

AIMS

To evaluate the reliability of bowel preparation quality scales when assessed by central readers.

METHODS

Four central readers evaluated 52 videos in triplicate, 2 weeks apart, during the entire endoscopic procedure (insertion/withdrawal of the colonoscope) and exclusively on colonoscope withdrawal using the Boston Bowel Preparation Scale (BBPS), Chicago Bowel Preparation scale, Harefield Cleansing Scale, Ottawa Bowel Preparation Quality Scale (OBPQS), Aronchick score, a visual analogue scale, and additional items proposed in a modified Research and Development/University of California Los Angeles appropriateness process. Reliability was assessed with intraclass correlation coefficients.

RESULTS

Intraclass correlation coefficients (95% confidence interval) for inter-rater reliability of the quality scales ranged from 0.51 to 0.65 (consistent with moderate to substantial inter-rater reliability) during the entire procedure. Corresponding intraclass correlation coefficients for intra-rater reliability ranged from 0.69 to 0.77 (consistent with substantial intra-rater reliability). Reliability was highest in the right colon and lowest in the left colon. No differences were observed in reliability when assessed for the procedure overall (insertion/withdrawal) relative to assessment on withdrawal alone.

CONCLUSION

All five bowel preparation quality scales had moderate to substantial inter-rater reliability. Panelists considered the Aronchick score too simplistic for clinical trials and recognized that assessment of residual fluid in the Ottawa Bowel Preparation Quality Scale was not amenable to central assessment.

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.

Management of pouch neoplasia: consensus guidelines from the International Ileal Pouch Consortium

Surveillance pouchoscopy is recommended for patients with restorative proctocolectomy with ileal pouch-anal anastomosis in ulcerative colitis or familial adenomatous polyposis, with the surveillance interval depending on the risk of neoplasia. Neoplasia in patients with ileal pouches mainly have a glandular source and less often are of squamous cell origin. Various grades of neoplasia can occur in the prepouch ileum, pouch body, rectal cuff, anal transition zone, anus, or perianal skin. The main treatment modalities are endoscopic polypectomy, endoscopic ablation, endoscopic mucosal resection, endoscopic submucosal dissection, surgical local excision, surgical circumferential resection and re-anastomosis, and pouch excision. The choice of the treatment modality is determined by the grade, location, size, and features of neoplastic lesions, along with patients' risk of neoplasia and comorbidities, and local endoscopic and surgical expertise.

Mediterranean-Like Dietary Pattern Associations With Gut Microbiome Composition and Subclinical Gastrointestinal Inflammation

BACKGROUND & AIMS

Case-control studies have shown that patients with Crohn's disease (CD) have a microbial composition different from healthy individuals. Although the causes of CD are unknown, epidemiologic studies suggest that diet is an important contributor to CD risk, potentially via modulation of bacterial composition and gut inflammation. We hypothesized that long-term dietary clusters (DCs) are associated with gut microbiome compositions and gut inflammation. Our objectives were to identify dietary patterns and assess whether they are associated with alterations in specific gut microbial compositions and subclinical levels of gut inflammation in a cohort of healthy first-degree relatives (FDRs) of patients with CD.

METHODS

As part of the Genetic, Environmental, Microbial (GEM) Project, we recruited a cohort of 2289 healthy FDRs of patients with CD. Individuals provided stool samples and answered a validated food frequency questionnaire reflecting their habitual diet during the year before sample collection. Unsupervised analysis identified 3 dietary and 3 microbial composition clusters.

RESULTS

DC3, resembling the Mediterranean diet, was strongly associated with a defined microbial composition, with an increased abundance of fiber-degrading bacteria, such as Ruminococcus, as well as taxa such as Faecalibacterium. The DC3 diet was also significantly associated with lower levels of subclinical gut inflammation, defined by fecal calprotectin, compared with other dietary patterns. No significant associations were found between individual food items and fecal calprotectin, suggesting that long-term dietary patterns rather than individual food items contribute to subclinical gut inflammation. Additionally, mediation analysis demonstrated that DC3 had a direct effect on subclinical inflammation that was partially mediated by the microbiota.

CONCLUSIONS

Overall, these results indicated that Mediterranean-like dietary patterns are associated with microbiome and lower intestinal inflammation. This study will help guide future dietary strategies that affect microbial composition and host gut inflammation to prevent diseases.

Large-scale sequencing identifies multiple genes and rare variants associated with Crohn's disease susceptibility

Genome-wide association studies (GWASs) have identified hundreds of loci associated with Crohn's disease (CD). However, as with all complex diseases, robust identification of the genes dysregulated by noncoding variants typically driving GWAS discoveries has been challenging. Here, to complement GWASs and better define actionable biological targets, we analyzed sequence data from more than 30,000 patients with CD and 80,000 population controls. We directly implicate ten genes in general onset CD for the first time to our knowledge via association to coding variation, four of which lie within established CD GWAS loci. In nine instances, a single coding variant is significantly associated, and in the tenth, ATG4C, we see additionally a significantly increased burden of very rare coding variants in CD cases. In addition to reiterating the central role of innate and adaptive immune cells as well as autophagy in CD pathogenesis, these newly associated genes highlight the emerging role of mesenchymal cells in the development and maintenance of intestinal inflammation.

Accelerated waning of immunity to SARS-CoV-2 mRNA vaccines in patients with immune-mediated inflammatory diseases

BACKGROUNDLimited information is available on the impact of immunosuppressants on COVID-19 vaccination in patients with immune-mediated inflammatory diseases (IMID).METHODSThis observational cohort study examined the immunogenicity of SARS-CoV-2 mRNA vaccines in adult patients with inflammatory bowel disease, rheumatoid arthritis, ankylosing spondylitis, or psoriatic disease, with or without maintenance immunosuppressive therapies. Ab and T cell responses to SARS-CoV-2, including neutralization against SARS-CoV-2 variants, were determined before and after 1 and 2 vaccine doses.RESULTSWe prospectively followed 150 subjects, 26 healthy controls, 9 patients with IMID on no treatment, 44 on anti-TNF, 16 on anti-TNF with methotrexate/azathioprine (MTX/AZA), 10 on anti-IL-23, 28 on anti-IL-12/23, 9 on anti-IL-17, and 8 on MTX/AZA. Ab and T cell responses to SARS-CoV-2 were detected in all participants, increasing from dose 1 to dose 2 and declining 3 months later, with greater attrition in patients with IMID compared with healthy controls. Ab levels and neutralization efficacy against variants of concern were substantially lower in anti-TNF-treated patients than in healthy controls and were undetectable against Omicron by 3 months after dose 2.CONCLUSIONSOur findings support the need for a third dose of the mRNA vaccine and for continued monitoring of immunity in these patient groups.FUNDINGFunded by a donation from Juan and Stefania Speck and by Canadian Institutes of Health (CIHR)/COVID-Immunity Task Force (CITF) grants VR-1 172711 and VS1-175545 (to THW and ACG), CIHR FDN-143250 (to THW), GA2-177716 (to VC, ACG, and THW), and GA1-177703 (to ACG) and the CIHR rapid response network to SARS-CoV-2 variants, CoVaRR-Net (to ACG).

The Toronto IBD Global Endoscopic Reporting [TIGER] Score: A Single, Easy to Use Endoscopic Score for Both Crohn's Disease and Ulcerative Colitis Patients

BACKGROUND AND AIMS

We constructed the Toronto IBD Global Endoscopic Reporting [TIGER] score for inflammatory bowel disease [IBD]. The aim of our study was to develop and validate the TIGER score against faecal calprotectin [FC], C-reactive protein [CRP], and IBD Disk.

METHODS

A cross-sectional study was performed among 113 adult patients (60 Crohn's disease [CD] and 53 ulcerative colitis [UC]). In the development and usability phase, blinded IBD experts reviewed and graded ileocolonoscopy videos. In the validity phase the TIGER score was compared with: [1] the Simple endoscopic Score for CD [SES-CD] and the Mayo endoscopic score in CD and UC, respectively; [2] FC and CRP; and [3] IBD Disk.

RESULTS

Inter-observer reliability of the TIGER score per segment between reviewers was excellent: interclass correlation coefficient [ICC] = 0.94 [95% CI: 0.92-0.96]. For CD patients, overall agreement per segment between SES-CD and TIGER was 91% [95% CI: 84-95] with kappa coefficient 0.77 [95% CI: 0.63-0.91]. There was a significant correlation between TIGER and CRP [p <0.0083], and TIGER and FC [p <0.0001]. In addition, there was significant correlation between TIGER and IBD Disk [p <0.0001]. For UC patients, overall agreement per segment between Mayo endoscopic score and TIGER was 84% [95% CI: 74%-90%] and kappa coefficient 0.60 [95% CI: 0.42-0.808]. There was a significant correlation between TIGER and FC [p <0.0001]. There was a significant correlation between TIGER and IBD Disk [p <0.0001].

CONCLUSIONS

The TIGER score is a reliable and simple novel endoscopic score that can be used for both CD and UC patients and captures full endoscopic disease burden.

The Toronto IBD Global Endoscopic Reporting [TIGER] Score: A Single, Easy to Use Endoscopic Score for Both Crohn's Disease and Ulcerative Colitis Patients

BACKGROUND AND AIMS

We constructed the Toronto IBD Global Endoscopic Reporting [TIGER] score for inflammatory bowel disease [IBD]. The aim of our study was to develop and validate the TIGER score against faecal calprotectin [FC], C-reactive protein [CRP], and IBD Disk.

METHODS

A cross-sectional study was performed among 113 adult patients (60 Crohn's disease [CD] and 53 ulcerative colitis [UC]). In the development and usability phase, blinded IBD experts reviewed and graded ileocolonoscopy videos. In the validity phase the TIGER score was compared with: [1] the Simple endoscopic Score for CD [SES-CD] and the Mayo endoscopic score in CD and UC, respectively; [2] FC and CRP; and [3] IBD Disk.

RESULTS

Inter-observer reliability of the TIGER score per segment between reviewers was excellent: interclass correlation coefficient [ICC] = 0.94 [95% CI: 0.92-0.96]. For CD patients, overall agreement per segment between SES-CD and TIGER was 91% [95% CI: 84-95] with kappa coefficient 0.77 [95% CI: 0.63-0.91]. There was a significant correlation between TIGER and CRP [p <0.0083], and TIGER and FC [p <0.0001]. In addition, there was significant correlation between TIGER and IBD Disk [p <0.0001]. For UC patients, overall agreement per segment between Mayo endoscopic score and TIGER was 84% [95% CI: 74%-90%] and kappa coefficient 0.60 [95% CI: 0.42-0.808]. There was a significant correlation between TIGER and FC [p <0.0001]. There was a significant correlation between TIGER and IBD Disk [p <0.0001].

CONCLUSIONS

The TIGER score is a reliable and simple novel endoscopic score that can be used for both CD and UC patients and captures full endoscopic disease burden.

Time to Revisit Disease Classification in Inflammatory Bowel Disease: Is the Current Classification of Inflammatory Bowel Disease Good Enough for Optimal Clinical Management?

Inflammatory bowel disease (IBD), historically subdivided into Crohn's disease and ulcerative colitis, is a very heterogeneous condition. While the tendency in medicine is to try to reduce complexity, IBD is a disease that cannot justify a one-size-fits-all principle. Our current clinical classification tools are suboptimal and need further refinement to capture, at least in part, the variety of phenotypes encountered in daily clinical practice. Although these revised classification tools alone will not be sufficient and should be complemented by more detailed molecular subclassifications, optimized clinical phenotypes can contribute to improved trial designs, future translational research approaches, and better treatment outcomes. In the current review, we discuss key clinical features important in IBD disease heterogeneity, tackle limitations of the current classification systems, propose some potential improvements, and raise priorities for future research in this domain.

A235 ILEAL MICROBIOME ALPHA DIVERSITY REMAINS LOWER IN ENDOSCOPICALLY AND HISTOLOGICALLY INACTIVE CROHN’S DISEASE COMPARED TO ULCERATIVE COLITIS OR HEALTHY CONTROLS

Background

Crohn’s disease (CD) has been associated with a lower alpha diversity when compared to ulcerative colitis (UC) patients and healthy controls (HC), which also depends on disease location and endoscopic activity. However, it is unclear whether the resolution of histologic inflammation may influence mucosal alpha diversity in the ileum.

Aims

To characterize the ileal mucosa-associated microbiome diversity in subjects with ileal predominant CD (iCD) in endoscopic (ER) and endo-histologic (EHR) remission, compared to subjects with colonic predominant CD (cCD), UC and HC, respectively.

Methods

Data from a large cohort of subjects recruited at Mount Sinai Hospital Toronto (2009–2016) was analyzed. ER was defined as a segmental Simple Endoscopic Score for CD of &lt;3 in the ileum. EHR was defined as ER with the absence of active histologic inflammation in ileal biopsies. CD patients were divided according to the Montreal classification into iCD (L1 and L3) and cCD (L2) and compared against UC patients without backwash ileitis and HC. Patients with history of ileocecal resection and/or antibiotic use at baseline were excluded. Microbial 16S rRNA gene was sequenced using the Illumina MiSeq and processed using QIIME2. Alpha diversity was measured using the Shannon index and compared using Kruskal-Wallis test and further pairwise Wilcoxon with Holm correction. An adjusted p-value &lt; 0.05 was considered significant.

Results

We included 35 CD patients with ileal ER, 81 UC patients and 32 HC. Among CD patients, 20/35 (57.1%) and 15/35 (42.9%) had iCD and cCD, respectively. Ileal mucosal alpha diversity was significantly lower in iCD patients in ER compared with that of UC patients (q=0.004) and HC (q=0.001). No differences in ileal mucosal alpha-diversity were seen between iCD than cCD patients (q=0.12). When histology was included to classify CD and UC patients as EHR, the ileal alpha diversity of iCD patients remained reduced compared to UC patients and HC (q=0.008 and q=0.002, respectively). Again, ileal mucosal alpha-diversity was not significantly lower in iCD than cCD patients among those in ileal EHR (q=0.24).

Conclusions

Ileal mucosa of CD patients in ER and EHR have lower alpha diversity than UC and HC. These findings suggest that the ileal mucosa of CD patients remains dysbiotic despite achieving endoscopic and histologic remission.

Funding Agencies

IBD Genetics Consortium

A161 MUCOSAL TRANSCRIPTOMICS IN NON-INFLAMED ILEUM OF CROHN’S DISEASE PATIENTS SHOWS DIFFERENTIALLY EXPRESSED GENE PROFILE COMPARED TO ILEUM OF HEALTHY CONTROLS

Background

The terminal ileum is the most susceptible location to develop Crohn’s disease (CD) and therefore is a valuable tissue to investigate biological mechanisms underlying chronic inflammation. Gene expression is highly affected by the level of inflammation, however, data on ileal transcriptomic profile in the absence of active inflammation is limited.

Aims

To investigate the ileal mucosal transcriptomic profile of CD patients in endoscopic and histologic remission compared to healthy controls (HC).

Methods

Ileal biopsies were collected during colonoscopy from patients with CD and HC. Biopsies were classified as non-inflamed based on endoscopic appearance and histologic criteria. Endo-histologic remission (EHR) was defined as simple endoscopic score < 3 and absence of active histologic inflammation. We included CD patients with EHR and HC for the analysis of this study. CD phenotype was divided into isolated colonic CD (cCD) that included Montreal L2 and ileal predominant CD (iCD) that included Montreal L1 and L3. Total RNA was extracted from samples, sequenced using a HiSeq 2500 instrument (Illumina, San Diego, CA, USA) and differential expression analysis was performed in EdgeR. Genes that were differentially expressed at the average of 2-fold-change (FC) in mean expression and False Discovery Rate (FDR) < 0.05 were considered significant.

Results

Ileal samples from 14 CD patients in EHR and 29 HC were included in the analysis. CD patients were significantly younger (median age 28.5 years, interquartile range (IQR)=24–40) compared with HC (median age 56 years, IQR=51–64). There were no differences in gender distribution (42.9% males in CD and 55.2% males in HC). We found 101 differentially expressed genes in CD patients compared to HC (99 genes were up-regulated and two were down-regulated). Dual oxidase 2 (DUOX2) and complement C6 were respectively the most significant up-regulated (logFC=4.45, FDR=1.3e-8) and down-regulated (logFC=-2.73, FDR=0.0006) genes in non-inflamed ileum CD group when compared with HC. In a subgroup analysis comparing ileal samples of CD patients with cCD (n=8) versus iCD phenotype (n=6), no differentially expressed genes were identified.

Conclusions

The mucosal transcriptomic profile of patients with inactive endoscopic and histologic ileal CD shows significant differentially expressed gene profile compared to ileal mucosa of HC. The clinical relevance of these findings should be further investigated.

Funding Agencies

IBD Genetics Consortium

A156 MUCOSA-ASSOCIATED MICROBIOTA OF ILEOCOLONIC CROHN’S DISEASE PATIENTS IS DISTINCT FROM COLONIC CROHN’S DISEASE AND ULCERATIVE COLITIS PATIENTS INDEPENDENT OF BIOPSY SITE, ENDOSCOPIC INFLAMMATION AND HOST GENETICS

Background

Colonic IBD encompassing ulcerative colitis (UC) and isolated colonic Crohn’s disease (cCD) shows significant clinical, therapeutic response and genetic differences compared to ileocolonic CD (icCD). Elucidating the microbial signatures characterizing these subphenotypes could help to understand the causal factors underlying these clinical dissimilarities

Aims

We compared the mucosal microbial diversity and differential abundance (DA) among disease locations (UC, cCD and icCD) accounting for potential clinical, endoscopic, and genetic confounders

Methods

Healthy control (HC), UC, cCD and icCD patients (including ileal and ileocolonic involvement) underwent colonoscopy. Biopsy samples were obtained from terminal ileum (TI), ascending colon (AC) and sigmoid colon (SC) for 16s rRNA gene profiling. Patients with prior ileocecal resection, IBD-unclassified and antibiotic exposure within 3 months before colonoscopy were excluded. Endoscopic inflammation was defined as a segmental Mayo endoscopic subscore = 0 in UC and a simple endoscopic score ≤ 2 in CD. A blood sample was drawn for genotyping and a weighted genetic risk score (GRS) was built based on 169 IBD risk variants found in our cohort. Alpha diversity (Chao1) and DA between IBD subphenotypes were compared using a linear mixed-effects model with subjects as random effect and adjusted for biopsy site, endoscopic inflammation, age, sex, and GRS. For DA analysis, the MaAsLin2 protocol was applied. All p-values were corrected by false discovery rate (FDR) with < 0.05 considered significant

Results

A total of 199 IBD patients and 44 HC with a mean age of 37.2 ± 14 were recruited. Of these, 113 (46.5%) were female. At colonoscopy, 535 biopsy samples (TI = 178, AC = 123 and SC = 234) were obtained. Considering disease location, 254, 55 and 148 samples were obtained from UC, cCD and icCD patients, respectively. A total of 168 samples (31.4%) showed endoscopic inflammation. Alpha diversity was significantly reduced in icCD when compared to either HC, UC or cCD. MaAsLin2 identified that the genera Agathobacter and Faecalibacterium, as well as the family Ruminococacceae and the order Oscillospirales were significantly reduced in icCD when compared to either HC, UC or cCD. These findings were independent of age, sex, endoscopic inflammation, biopsied site, and GRS. UC and cCD did not show differences in their microbial profile

Conclusions

Mucosal samples from UC and cCD patients showed marked similarities in their microbial profile while icCD is characterized by a significant decrease in diversity and beneficial microbes. These data suggest that disease location is the main driver of the mucosal microbial landscape independent of IBD GRS

Funding Agencies

NoneNIDDK IBD Genetics Consortium

A236 ASSOCIATION OF STOOL METABOLOMIC PROFILE AND MICROBIOME COMPOSITION RISK SCORE WITH FUTURE ONSET OF CROHN’S DISEASE

Background

Microbial composition-based risk score (MRS) was recently developed and validated to predict future risk of developing Crohn’s disease (CD) among healthy first-degree relatives (FDR) of CD patients. We hypothesized that stool metabolomic profiles, some of which are linked to the gut microbiome, are associated with future risk of CD.

Aims

To assess the association of stool metabolomic profile with onset of CD and to determine the correlation between stool metabolites and the MRS

Methods

Healthy FDR of CD patients were recruited as part of the nested case-control cohort of the CCC-GEM Project. Healthy FDRs who later developed CD (n=56) were matched approximately 1:1 by age, sex, follow-up duration, and geographical location with control FDRs remaining healthy (n=66). Stool metabolomics were assessed using the Metabolon’s DiscoveryHD4™ platform, and the stool microbiome characterised by 16s rDNA amplicon sequencing. We fitted a multivariable conditional logistic regression model on the disease status as a function of individual stool metabolites. We additionally performed Spearman correlation between each stool metabolite and the MRS.

Results

Among 1,029 stool metabolites that were analyzed, 79 were associated with future risk of CD (p&lt;0.05); however, none remained significant after multiple testing correction (FDR correction). Considering the exploratory nature of this study with limited sample size, we focused on the top seven metabolites associated with CD onset (p&lt;0.01). Of these, two stool metabolites (dimethylglycine, methylmyristate) were associated with increased risk of CD onset while five (cytosine, guanine, cytidine, hydroxyglutarate, nervonate) were associated with decreased risk of developing CD. The two metabolites positively associated with CD onset were positively correlated with the MRS, while the five metabolites negatively associated with CD onset, were negatively correlated with the MRS. Meanwhile, 24 stool metabolites had significant correlation with MRS (FDR-corrected p&lt;0.2). Among those, a total of four stool metabolites (cytosine, guanine, methymyristate, cytidine) overlapped with the top seven stool metabolites associated with CD onset.

Conclusions

Stool metabolite profiles may predict future risk of CD. A subset of these metabolites have significant correlation with the MRS with consistent direction of effect. This may suggest that stool metabolites mediate the putative effect of the gut microbiome on CD risk. Further validation in the full GEM cohort is warranted.

Funding Agencies

CCC, CIHRThe Leona M. and Harry B. Helmsley Charitable Trust; Kenneth Croitoru is the recipient of the Canada Research Chair in Inflammatory Bowel Diseases; Sun-Ho Lee is a recipient of the Imagine/ CIHR/CAG Fellowship Award; Sun-Ho Lee, Juan Antonio Raygoza Garay, and Williams Turpin are recipients of fellowship awards from the Department of Medicine, Mount Sinai Hospital, Toronto, Canada.

Patients With Low Drug Levels or Antibodies to a Prior Anti-Tumor Necrosis Factor Are More Likely to Develop Antibodies to a Subsequent Anti-Tumor Necrosis Factor

Therapeutic drug monitoring (TDM) with measurement of serum drug and antidrug antibodies (ADAb) is used widely to confirm therapeutic exposure, rule out immunogenicity, and optimize treatment of biologics in patients with inflammatory bowel diseases.¹ A recent genome-wide association study found the variant HLA-DQA1∗05 to increase the risk of development of antibodies against infliximab (IFX) and adalimumab (ADM) 2-fold, regardless of concomitant immunomodulator use.^2,3 However, there is currently limited evidence showing whether patients who develop antibodies to 1 anti-tumor necrosis factor (TNF) are prone to develop antibodies to the subsequent anti-TNF. Our aim was to investigate the risk of subsequent antibody development in cases (with ADAb to prior anti-TNF) versus control subjects (without ADAb to prior anti-TNF) using a large cohort of patients with inflammatory bowel diseases who underwent TDM with a drug-tolerant assay.

Combined Histo-endoscopic Remission but not Endoscopic Healing Alone in Ulcerative Colitis is Associated with a Mucosal Transcriptional Profile Resembling Healthy Mucosa

BACKGROUND AND AIMS

A composite endpoint of histological and endoscopic remission is proposed to be the most complete measure of mucosal healing in ulcerative colitis [UC]. We aim to establish the prognosis, and transcriptional and microbial features of histo-endoscopic remission and activity.

METHODS

A cross-sectional endoscopic rectosigmoid colon sample collection from UC patients and healthy controls [HC] was performed for histopathology and host genome-wide RNA-sequencing. Histo-endoscopic remission and histo-endoscopic activity were defined as Mayo endoscopic subscore [MES] 0-1 with and without histological activity, respectively. UC relapse, defined as symptomatic and endoscopic worsening, was retrospectively recorded for survival analysis. Unsupervised and differential gene expression analyses were performed, and the interaction between transcriptomics and mucosal gut microbiota was analysed based on the 16S rRNA gene sequencing profile.

RESULTS

UC patients with histo-endoscopic remission showed a significantly lower risk of relapse compared to histo-endoscopic activity. Unsupervised analysis of the transcriptomic profile showed that histo-endoscopic remission and histo-endoscopic activity samples clustered with HC and MES 2-3 samples, respectively. A total of 452 host genes enriched for humoral immune response, antimicrobial defence, chemokine and TH17 signalling pathway were upregulated in histo-endoscopic activity compared to histo-endoscopic remission. A set of host genes with antimicrobial properties showed significant associations with mucosal microbiota.

CONCLUSIONS

The rectosigmoid mucosa transcriptional profile of UC patients in histo-endoscopic remission resembles that of HC mucosa and confers a lower risk of relapse. These data support that the combination of histo-endoscopic remission could be the most appropriate definition of mucosal healing in UC.

Serum Analyte Profiles Associated With Crohn's Disease and Disease Location

BACKGROUND

Crohn's disease (CD) can affect any segment of the digestive tract but is most often localized in the ileal, ileocolonic, and colorectal regions of the intestines. It is believed that the chronic inflammation in CD is a result of an imbalance between the epithelial barrier, the immune system, and the intestinal microbiota. The aim of the study was to identify circulating markers associated with CD and/or disease location in CD patients.

METHODS

We tested 49 cytokines, chemokines, and growth factors in serum samples from 300 patients with CD and 300 controls. After quality control, analyte levels were tested for association with CD and disease location.

RESULTS

We identified 13 analytes that were higher in CD patients relative to healthy controls and that remained significant after conservative Bonferroni correction (P < 0.0015). In particular, CXCL9, CXCL1, and interleukin IL-6 had the greatest effect and were highly significant (P < 5 × 10-7). We also identified 9 analytes that were associated with disease location, with VEGF, IL-12p70, and IL-6 being elevated in patients with colorectal disease (P < 3 × 10-4).

CONCLUSIONS

Multiple serum analytes are elevated in CD. These implicate the involvement of multiple cell types from the immune, epithelial, and endothelial systems, suggesting that circulating analytes reflect the inflammatory processes that are ongoing within the gut. Moreover, the identification of distinct profiles according to disease location supports the existence of a biological difference between ileal and colonic CD, consistent with previous genetic and clinical observations.

Treatment of pouchitis, Crohn's disease, cuffitis, and other inflammatory disorders of the pouch: consensus guidelines from the International Ileal Pouch Consortium

Pouchitis, Crohn's disease of the pouch, cuffitis, polyps, and extraintestinal manifestations of inflammatory bowel disease are common inflammatory disorders of the ileal pouch. Acute pouchitis is treated with oral antibiotics and chronic pouchitis often requires anti-inflammatory therapy, including the use of biologics. Aetiological factors for secondary pouchitis should be evaluated and managed accordingly. Crohn's disease of the pouch is usually treated with biologics and its stricturing and fistulising complications can be treated with endoscopy or surgery. The underlying cause of cuffitis determines treatment strategies. Endoscopic polypectomy is recommended for large, symptomatic inflammatory polyps and polyps in the cuff. The management principles of extraintestinal manifestations of inflammatory bowel disease in patients with pouches are similar to those in patients without pouches.

Anti-Microbial Antibody Response is Associated With Future Onset of Crohn's Disease Independent of Biomarkers of Altered Gut Barrier Function, Subclinical Inflammation, and Genetic Risk

BACKGROUND AND AIMS

Altered host immune reactivity to microbial antigens is hypothesized to trigger the onset of Crohn's disease (CD). We aimed to assess whether increased serum anti-microbial antibody response in asymptomatic first-degree relatives (FDRs) of CD patients is an independent risk factor for future CD development.

METHODS

We measured host serum antibody response to 6 microbial antigens at enrollment (Prometheus enzyme-linked immunosorbent assay test: anti-Saccharomyces cerevisiae antibodies immunoglobulin A/immunoglobulin G, anti-OmpC, anti-A4-Fla2, anti-FlaX, anti-CBir1) and derived the sum of positive antibodies (AS). We used samples at enrollment of prospectively followed healthy FDRs from a nested case-control cohort of the Crohn's and Colitis Canada Genetics Environment Microbial Project. Those who later developed CD (n = 77) were matched 1:4 by age, sex, follow-up duration, and geographic location with control FDRs remaining healthy (n = 307). To address our research aims, we fitted a multivariable conditional logistic regression model and performed causal mediation analysis.

RESULTS

High baseline AS (≥2) (43% of cases, 11% of controls) was associated with higher risk of developing CD (adjusted odds ratio, 6.5; 95% confidence interval, 3.4-12.7; P < .001). Importantly, this association remained significant when adjusted for markers of gut barrier function, fecal calprotectin, C-reactive protein, and CD-polygenic risk score, and in subjects recruited more than 3 years before diagnosis. Causal mediation analysis showed that the effect of high AS on future CD development is partially mediated (42%) via preclinical gut inflammation.

CONCLUSIONS

Our results suggest that increased anti-microbial antibody responses are associated with risk of future development of CD, independent of biomarkers of abnormal gut barrier function, subclinical inflammation, and CD-related genetic risks. This suggests that anti-microbial antibody responses are an early predisease event in the development of CD.

A Role for CXCR3 Ligands as Biomarkers of Post-Operative Crohn's Disease Recurrence

BACKGROUND AND AIMS

Crohn's disease [CD] recurrence following ileocolic resection [ICR] is common. We sought to identify blood-based biomarkers associated with CD recurrence.

METHODS

CD patients undergoing ICR were recruited across six centres. Serum samples were obtained at post-operative colonoscopy. A multiplex immunoassay was used to analyse 92 inflammation-related proteins [Olink Proteomics]. Bayesian analysis was used to identify proteins associated with increasing Rutgeerts score. Identified proteins were used in receiver operating characteristic [ROC] analysis to examine the ability to identify CD recurrence [Rutgeerts score ≥i2]. Existing single cell data were interrogated to further elucidate the role of the identified proteins.

RESULTS

Data from 276 colonoscopies in 213 patients were available. Median time from surgery to first and second colonoscopy was 7 (interquartile range [IQR] 6-9) and 19 [IQR 16-23] months, respectively. Disease recurrence was evident at 60 [30%] first and 36 [49%] second colonoscopies. Of 14 proteins significantly associated with Rutgeerts score, the strongest signal was seen for CXCL9 and MMP1. Among patients on anti-tumour necrosis factor drugs, CXCL9 and CXCL11 were most strongly associated with Rutgeerts score. Both are CXCR3 ligands. Incorporation of identified proteins into ROC analysis improved the ability to identify disease recurrence as compared to C-reactive protein alone: area under the curve [AUC] 0.75 (95% confidence interval [CI]: 0.66-0.82] vs 0.64 [95% CI 0.56-0.72], p = 0.012. Single cell transcriptomic data provide evidence that innate immune cells are the primary source of the identified proteins.

CONCLUSIONS

CXCR3 ligands are associated with CD recurrence following ICR. Incorporation of novel blood-based candidate biomarkers may aid in identification of CD recurrence.

Post-Induction High Adalimumab Drug Levels Predict Biological Remission at Week 24 in Patients With Crohn's Disease

INTRODUCTION

We investigated whether early adalimumab drug levels (ADL) at week 4 predicted biological remission at week 24.

METHODS

In a prospective study, we assessed clinical and biological remission at weeks 0, 4, 12, and 24 after induction of adalimumab in 33 patients with Crohn's disease. Disease activity was determined by the Harvey-Bradshaw Index, ileocolonoscopy reports, cross-sectional imaging, C-reactive protein (CRP), and fecal calprotectin (FC) levels. Clinical remission was defined as Harvey-Bradshaw Index <5. Biological remission was defined as a combination of FC < 200 μg/g and CRP <5 μg/mL. ADL trough levels were tested using a liquid phase, mobility shift assay.

RESULTS

At 24 weeks, 18/33 (55%) of the patients were with biological remission. Ten (30%) patients required dose escalation or withdrawal from adalimumab by week 24 because of lack of response and exhibited significantly higher FC (P = 0.003) and CRP (P = 0.002). ADL levels at week 4 (19.8 μg/mL vs 10.2 μg/mL, P = 0.001) were significantly higher in patients with biological remission vs nonresponders at week 24. ADL levels at week 4 were a good predictor of biological remission at week 24, with area under the curve 0.86, 95% confidence interval (1.1; 1.67) and for combined biological and clinical remission, with area under the curve 0.8. The best ADL cutoff at week 4 that predicted biological remission at week 24 was 13.9 μg/mL (sensitivity 94.4% and specificity 73.3%).

DISCUSSION

In individuals with Crohn's disease, higher adalimumab drug levels at week 4 (>13.9 μg/mL) were significantly associated with biological remission at week 24.

Comparative effectiveness of higher adalimumab maintenance therapy versus standard dose in anti-tumor necrosis factor experienced Crohn's disease patients: A propensity-score matched cohort analysis

BACKGROUND AND AIM

Crohn's disease (CD) patients who previously failed anti-tumor necrosis factor (TNF) therapy are at higher risk of treatment failure with subsequent biologics. This study aims to determine the effectiveness and safety of higher maintenance dose regimens of adalimumab compared with standard doses in CD patients who failed anti-TNF.

METHODS

In this retrospective observational study, CD patients who failed anti-TNF and received adalimumab were categorized according to their post-induction maintenance regimen; 40 mg subcutaneous (sc) weekly or 80 mg sc every other week were defined as a high-dose (HD) maintenance regimen, and 40 mg sc every other week was defined as a standard-dose (SD) maintenance regimen. The primary outcome was time to treatment failure. Cox proportional hazards regression was used to adjust for confounders. Sensitivity analysis was conducted using propensity scores to create a cohort of matched participants with similar distribution of baseline covariates.

RESULTS

Forty patients started on HD regimens following induction, and 77 patients received the SD regimen. The median time to failure in the HD group was 6.6 years (interquartile range [IQR] 4.0-9.6) and 3.0 years (IQR 0.9-9.4) in the SD group (log-rank test P = 0.006). Patients on HD adalimumab had a lower hazard rate of treatment failure (hazard ratio: 0.27; 95% confidence interval [0.12, 0.62]; P = 0.002) compared with SD patients. No difference in adverse events was identified between groups (30% vs 31.2%, P = 1.0). Results were similar in the propensity score-matched cohort.

CONCLUSIONS

High-dose maintenance regimens were associated with longer time-to-failure as compared with SD regimens in CD patient who failed anti-TNF.

Higher adalimumab maintenance regimen is more effective than standard dose in anti-TNF experienced Crohn's disease patients

BACKGROUND

Many Crohn's disease patients treated with anti-tumor necrosis factor (TNF) therapies suffer from loss of response over time and require dose escalation. The aim of this study was to evaluate the efficacy and safety of treating anti-TNF experienced Crohn's disease patients with higher maintenance regimens of adalimumab.

METHODS

In a retrospective observational study, Crohn's disease patients receiving adalimumab were categorized according to their maintenance regimen; 40 mg weekly, 80 mg every other week or greater were defined as a high-dose maintenance regimen and 40 mg every other week was defined as a standard maintenance regimen. The primary outcome was time to treatment failure.

RESULTS

Thirty-nine patients were started on high-dose regimens following induction and 40 patients received the standard regimen. According to a Kaplan-Meier survival curve analysis, time to treatment failure was significantly longer in patients in the high-dose group (P = 0.0015). Patients on high-dose adalimumab had a lower treatment failure rate (hazard ratio 0.21; P = 0.0005) when compared to patients on the standard regimen, after adjusting for induction dose and concomitant immunomodulator use. No difference in adverse events was identified between the groups (31 vs. 30%; P = 0.94).

CONCLUSION

High-dose maintenance regimens were more effective than the standard adalimumab maintenance protocol with better short and long-term clinical outcomes.

Diagnosis and classification of ileal pouch disorders: consensus guidelines from the International Ileal Pouch Consortium

Restorative proctocolectomy with ileal pouch-anal anastomosis is an option for most patients with ulcerative colitis or familial adenomatous polyposis who require colectomy. Although the construction of an ileal pouch substantially improves patients' health-related quality of life, the surgery is, directly or indirectly, associated with various structural, inflammatory, and functional adverse sequelae. Furthermore, the surgical procedure does not completely abolish the risk for neoplasia. Patients with ileal pouches often present with extraintestinal, systemic inflammatory conditions. The International Ileal Pouch Consortium was established to create this consensus document on the diagnosis and classification of ileal pouch disorders using available evidence and the panellists' expertise. In a given individual, the condition of the pouch can change over time. Therefore, close monitoring of the activity and progression of the disease is essential to make accurate modifications in the diagnosis and classification in a timely manner.

Early Changes in Serum Albumin Predict Clinical and Endoscopic Outcomes in Patients With Ulcerative Colitis Starting Anti-TNF Treatment

BACKGROUND

Up to 60% of patients with ulcerative colitis (UC) ultimately fail anti-tumor necrosis factor (TNF) treatment. We aimed to investigate early predictive markers of clinical and endoscopic outcomes in patients with UC who were anti-TNF-naïve commencing anti-TNF treatment, with particular focus on changes in albumin and C-reactive protein levels in the first 2 weeks of treatment.

METHODS

We retrospectively investigated 210 patients with UC who started infliximab or adalimumab between 2009 and 2016 (male, 62.4%; median age at diagnosis, 37.9 years [interquartile range, 25.5-48.9 years]; median follow-up duration, 3.3 years [1.9-5.0 years]). Logistic and Cox proportional-hazards regressions were performed to identify variables associated with primary nonresponse (PNR), endoscopic outcomes, time-to-colectomy, and anti-TNF failure.

RESULTS

Forty-one patients (19.5%) experienced PNR; week 0/week 2 ratio serum albumin was associated with PNR (adjusted odds ratio [aOR], 1.8; 95% confidence interval [CI], 1.1-2.9, per interquartile range increase). Week 0/week 2 ratio albumin was also associated with endoscopic response (aOR, 0.28; 95% CI, 0.31-0.82) and endoscopic remission (aOR, 0.61; 95% CI, 0.39-0.96) at weeks 8 to 14, time-to-colectomy (adjusted hazard ratio, 2.12; 95% CI, 1.29-3.49) and time-to-anti-TNF failure (adjusted hazard ratio, 1.54; 95% CI, 1.22-1.96), regardless of age, disease severity, or in-patient status. Association with time-to-colectomy and anti-TNF failure was externally validated in an independent cohort of inpatients with UC starting infliximab.

CONCLUSIONS

Change in serum albumin within the first 2 weeks of anti-TNF treatment is predictive of PNR, endoscopic outcomes, time-to-colectomy, and anti-TNF failure in patients with UC. Timely access to this biomarker enables early identification of patients with UC at risk of anti-TNF failure and may guide early optimization of anti-TNF treatment to improve disease outcomes.

Serum Ustekinumab Concentrations Are Associated With Remission in Crohn's Disease Defined by a Serum-Based Endoscopic Healing Index

Background

Optimal ustekinumab levels (UST) in Crohn disease (CD) treatment have not been defined. We set out to define the optimal UST to differentiate between remission and active CD, as defined using the serum-based endoscopic healing index (EHI).

Methods

Paired serum UST and EHI tests were analyzed. Remission was defined as EHI <20. Active disease was defined as EHI ≥50. The proportion of patients in remission was compared across UST quartiles. UST in subjects with EHI <20 and EHI ≥50 were compared. An area under receiver operating characteristic curve was generated to identify an optimal UST to differentiate between active disease and remission.

Results

A total of 337 unique patients were identified; median UST and EHI were 5.0 µg/mL [interquartile range (IQR) 2.7-9.1] and 37 (IQR 26-53), respectively. EHI <20 (remission) was found in 57 (16.9%) patients. EHI ≥50 (active disease) was found in 97 (28.8%) patients. Higher proportions of subjects were in remission for increasing UST quartiles, P = 0.01. Median UST in patients with EHI <20 and EHI ≥50 were 7.5 µg/mL (IQR 4.6-10.9) and 3.1 µg/mL (IQR 1.8-6.6), respectively, P < 0.001. An UST threshold of 3.75 µg/mL optimally differentiated between active disease and remission (area under the curve 0.725). UST levels >3.75 µg/mL were associated with a lower proportion of subjects with active disease (EHI ≥50; 18.9%) compared with UST levels ≤3.75 µg/mL (45.6%, P < 0.001).

Conclusions

Using the EHI, we identified a threshold UST level of 3.75 µg/mL to optimally differentiate between active and quiescent CD. These data suggest that UST serum concentrations of >3.75 µg/mL are optimally associated with endoscopic remission in CD.

Integrative Analysis of Colonic Biopsies from Inflammatory Bowel Disease Patients Identifies an Interaction Between Microbial Bile Acid-inducible Gene Abundance and Human Angiopoietin-like 4 Gene Expression

BACKGROUND AND AIMS

Microbial-derived bile acids can modulate host gene expression, and their faecal abundance is decreased in active inflammatory bowel disease [IBD]. We analysed the impact of endoscopic inflammation on microbial genes involved in bile acid biotransformation, and their interaction with host transcriptome in the intestinal mucosa of IBD patients.

METHODS

Endoscopic mucosal biopsies were collected from non-inflamed and inflamed terminal ileum, ascending and sigmoid colon of IBD patients. Prediction of imputed metagenome functional content from 16S rRNA profile and real-time quantitative polymerase chain reaction [qPCR] were utsed to assess microbial bile acid biotransformation gene abundance, and RNA-seq was used for host transcriptome analysis. Linear regression and partial Spearman correlation accounting for age, sex, and IBD type were used to assess the association between microbial genes, inflammation, and host transcriptomics in each biopsy location. A Bayesian network [BN] analysis was fitted to infer the direction of interactions between IBD traits and microbial and host genes.

RESULTS

The inferred microbial gene pathway involved in secondary bile acid biosynthesis [ko00121 pathway] was depleted in inflamed terminal ileum of IBD patients compared with non-inflamed tissue. In non-inflamed sigmoid colon, the relative abundance of bile acid-inducible [baiCD] microbial genes was positively correlated with the host Angiopoietin-like 4 [Angptl4] gene expression. The BN analysis suggests that the microbial baiCD gene abundance could affect Angptl4 expression, and this interaction appears to be lost in the presence of inflammation.

CONCLUSIONS

Endoscopic inflammation affects the abundance of crucial microbial bile acid-metabolising genes and their interaction with Angptl4 in intestinal mucosa of IBD patients.

An expert consensus to standardise clinical, endoscopic and histologic items and inclusion and outcome criteria for evaluation of pouchitis disease activity in clinical trials

BACKGROUND

Pouchitis is a condition with large unmet medical needs and no approved therapies. Lack of validated instruments to measure disease activity and treatment response is a major barrier to drug development.

AIM

To conduct a modified RAND/University of California Los Angeles appropriateness process to produce a standardised assessment of pouchitis disease activity in clinical trials.

METHODS

A list of 164 items generated upon a systematic review and expert opinion were rated based on a 9-point scale (appropriate, uncertain and inappropriate), by a panel including 16 gastroenterologists, surgeons and histopathologists.

RESULTS

Items rated as appropriate to evaluate in pouchitis clinical trials were: (a) clinical: stool frequency and faecal urgency; (b) endoscopic: primary assessment in the pouch body according to the percentage of affected area (<50%, 50%-75% and >75%), evaluation of the presence of ulcers/erosions according to size (erosions <5 mm, ulcers ≥5 mm to 2 cm and large ulcers >2 cm) and ulcerated area (<10%, 10%-30% and >30%); (c) histologic: two biopsies from each segment, from the ulcer's edge when present, or endoscopically normal areas, assessment of lamina propria chronic inflammation, epithelial and lamina propria neutrophils, epithelial damage, erosions and ulcers; and (d) clinical trial inclusion/outcome criteria: minimum histologic disease activity for inclusion, a primary endpoint based on stool frequency and assessment of clinical, endoscopic and histologic response and remission. The overall majority of items surveyed (100/164) were rated 'uncertain'.

CONCLUSION

We conducted a RAND/UCLA appropriateness process to help inform measurement of pouchitis disease activity within clinical trials and foster the development of novel therapies.

Inflamed Ulcerative Colitis Regions Associated With MRGPRX2-Mediated Mast Cell Degranulation and Cell Activation Modules, Defining a New Therapeutic Target

BACKGROUND & AIMS

Recent literature has implicated a key role for mast cells in murine models of colonic inflammation, but their role in human ulcerative colitis (UC) is not well established. A major advance has been the identification of mrgprb2 (human orthologue, MRGPX2) as mediating IgE-independent mast cell activation. We sought to define mechanisms of mast cell activation and MRGPRX2 in human UC.

METHODS

Colon tissues were collected from patients with UC for bulk RNA sequencing and lamina propria cells were isolated for MRGPRX2 activation studies and single-cell RNA sequencing. Genetic association of all protein-altering G-protein coupled receptor single-nucleotide polymorphism was performed in an Ashkenazi Jewish UC case-control cohort. Variants of MRGPRX2 were transfected into Chinese hamster ovary (CHO) and human mast cell (HMC) 1.1 cells to detect genotype-dependent effects on β-arrestin recruitment, IP-1 accumulation, and phosphorylated extracellular signal-regulated kinase.

RESULTS

Mast cell-specific mediators and adrenomedullin (proteolytic precursor of PAMP-12, an MRGPRX2 agonist) are up-regulated in inflamed compared to uninflamed UC. MRGPRX2 stimulation induces carboxypeptidase secretion from inflamed UC. Of all protein-altering GPCR alleles, a unique variant of MRGPRX2, Asn62Ser, was most associated with and was bioinformatically predicted to alter arrestin recruitment. We validated that the UC protective serine allele enhances β-arrestin recruitment, decreases IP-1, and increases phosphorylated extracellular signal-regulated kinase with MRGPRX2 agonists. Single-cell RNA sequencing defines that adrenomedullin is expressed by activated fibroblasts and epithelial cells and that interferon gamma is a key upstream regulator of mast cell gene expression.

CONCLUSION

Inflamed UC regions are distinguished by MRGPRX2-mediated activation of mast cells, with decreased activation observed with a UC-protective genetic variant. These results define cell modules of UC activation and a new therapeutic target.

Common and Rare Variant Prediction and Penetrance of IBD in a Large, Multi-ethnic, Health System-based Biobank Cohort

BACKGROUND AND AIMS

Polygenic risk scores (PRS) may soon be used to predict inflammatory bowel disease (IBD) risk in prevention efforts. We leveraged exome-sequence and single nucleotide polymorphism (SNP) array data from 29,358 individuals in the multiethnic, randomly ascertained health system-based BioMe biobank to define effects of common and rare IBD variants on disease prediction and pathophysiology.

METHODS

PRS were calculated from European, African American, and Ashkenazi Jewish (AJ) reference case-control studies, and a meta-GWAS run using all three association datasets. PRS were then combined using regression to assess which combination of scores best predicted IBD status in European, AJ, Hispanic, and African American cohorts in BioMe. Additionally, rare variants were assessed in genes associated with very early-onset IBD (VEO-IBD), by estimating genetic penetrance in each BioMe population.

RESULTS

Combining risk scores based on association data from distinct ancestral populations improved IBD prediction for every population in BioMe and significantly improved prediction among European ancestry UK Biobank individuals. Lower predictive power for non-Europeans was observed, reflecting in part substantially lower African IBD case-control reference sizes. We replicated associations for two VEO-IBD genes, ADAM17 and LRBA, with high dominant model penetrance in BioMe. Autosomal recessive LRBA risk alleles are associated with severe, early-onset autoimmunity; we show that heterozygous carriage of an African-predominant LRBA protein-altering allele is associated with significantly decreased LRBA and CTLA-4 expression with T-cell activation.

CONCLUSIONS

Greater genetic diversity in African populations improves prediction across populations, and generalizes some VEO-IBD genes. Increasing African American IBD case-collections should be prioritized to reduce health disparities and enhance pathophysiological insight.

Vedolizumab and Anti-Tumour Necrosis Factor α Real-World Outcomes in Biologic-Naïve Inflammatory Bowel Disease Patients: Results from the EVOLVE Study

BACKGROUND AND AIMS

This study aimed to compare real-world clinical effectiveness and safety of vedolizumab, an α4β7-integrin inhibitor, and anti-tumour necrosis factor-α [anti-TNFα] agents in biologic-naïve ulcerative colitis [UC] and Crohn's disease [CD] patients.

METHODS

This was a 24-month retrospective medical chart study in adult UC and CD patients treated with vedolizumab or anti-TNFα in Canada, Greece and the USA. Inverse probability weighting was used to account for differences between groups. Primary outcomes were cumulative rates of clinical effectiveness [clinical response, clinical remission, mucosal healing] and incidence rates of serious adverse events [SAEs] and serious infections [SIs]. Secondary outcomes included cumulative rates of treatment persistence [patients who did not discontinue index treatment during follow-up] and dose escalation and incidence rates of disease exacerbations and disease-related surgeries. Adjusted analyses were performed using inverse probability weighting.

RESULTS

A total of 1095 patients [604 UC, 491 CD] were included. By 24 months, rates of clinical effectiveness were similar between groups, but incidence rates of SAEs (hazard ratio [HR] = 0.42 [0.28-0.62]) and SIs (HR = 0.40 [0.19-0.85]) were significantly lower in vedolizumab vs anti-TNFα patients. Rates of treatment persistence [p < 0.01] by 24 months were higher in vedolizumab patients with UC. Incidence rates of disease exacerbations were lower in vedolizumab patients with UC (HR = 0.58 [0.45-0.76]). Other outcomes did not significantly differ between groups.

CONCLUSION

In this real-world setting, first-line biologic therapy in biologic-naïve patients with UC and CD demonstrated that vedolizumab and anti-TNFα treatments were equally effective at controlling disease symptoms, but vedolizumab has a more favourable safety profile.

Whole-genome sequencing of African Americans implicates differential genetic architecture in inflammatory bowel disease

Whether or not populations diverge with respect to the genetic contribution to risk of specific complex diseases is relevant to understanding the evolution of susceptibility and origins of health disparities. Here, we describe a large-scale whole-genome sequencing study of inflammatory bowel disease encompassing 1,774 affected individuals and 1,644 healthy control Americans with African ancestry (African Americans). Although no new loci for inflammatory bowel disease are discovered at genome-wide significance levels, we identify numerous instances of differential effect sizes in combination with divergent allele frequencies. For example, the major effect at PTGER4 fine maps to a single credible interval of 22 SNPs corresponding to one of four independent associations at the locus in European ancestry individuals but with an elevated odds ratio for Crohn disease in African Americans. A rare variant aggregate analysis implicates Ca²⁺-binding neuro-immunomodulator CALB2 in ulcerative colitis. Highly significant overall overlap of common variant risk for inflammatory bowel disease susceptibility between individuals with African and European ancestries was observed, with 41 of 241 previously known lead variants replicated and overall correlations in effect sizes of 0.68 for combined inflammatory bowel disease. Nevertheless, subtle differences influence the performance of polygenic risk scores, and we show that ancestry-appropriate weights significantly improve polygenic prediction in the highest percentiles of risk. The median amount of variance explained per locus remains the same in African and European cohorts, providing evidence for compensation of effect sizes as allele frequencies diverge, as expected under a highly polygenic model of disease.

Persistent Diarrhea in Patients With Crohn's Disease After Mucosal Healing Is Associated With Lower Diversity of the Intestinal Microbiome and Increased Dysbiosis

BACKGROUND & AIMS

In patients with inflammatory bowel diseases (IBDs), symptoms do not always associate with the severity of endoscopic inflammation and can persist after mucosal healing. We investigated whether symptoms in patients with successfully treated IBD are related to the composition of the intestinal microbiome.

METHODS

We analyzed 590 tissue biopsy specimens from 215 patients with IBD and 48 healthy individuals (controls). We obtained mucosal biopsy specimens from 2 colon sites (ascending and rectosigmoid) and from the terminal ileum along with clinical data. Bacterial DNA was extracted from the biopsy specimens and the V4 region of 16s ribosomal RNA sequenced by Miseq and processed using the QIIME v1.9 pipeline.

RESULTS

Mucosal biopsy specimens from patients with Crohn's disease (CD) who achieved mucosal healing (Mayo scores of 0-1 or segmental endoscopic severity CD scores of 0-5) had lower Chao1 diversity than biopsy specimens from patients with ulcerative colitis (UC) or unclassified IBD (IBD-U), or controls. After endoscopic evidence of improvement in patients with UC or IBD-U, diversity of the tissue-associated microbiota did not differ significantly from that of controls. Colon biopsy specimens from patients with CD had lower microbial diversity, before and after healing (segmental endoscopic severity CD scores, 0-2), than colon biopsy specimens from controls (P < .002). In patients with CD who achieved mucosal healing, residual clinical activity (CD activity index scores >150; P = .03) and persistent diarrhea were associated with reduced microbial diversity (P = .01). Continued diarrhea was associated with a trend toward dysbiosis, based on the microbial dysbiosis index (P = .059). In patients with UC or IBD-U with moderate to severe inflammation, increasing severity of diarrhea was associated with reduced microbial diversity (P = .03).

CONCLUSIONS

In an analysis of biopsy specimens from patients with IBD and controls, we found that despite endoscopic evidence of improvement or remission, α-diversity of the tissue-associated intestinal microbiome remained lower in patients with CD than in controls. This observation, along with the reduced Chao1 diversity and greater dysbiosis in intestinal microbiota of patients with residual symptoms of IBD, indicates that microbiome composition could be associated with persistent diarrhea.