Evaluation of optimal biopsy location for assessment of histological activity, transcriptomic and immunohistochemical analyses in patients with active Crohn's disease

Biopsies from ulcer edge yield higher histological activity scores than biopsies from non-ulcerated mucosa in active ulcerative colitis

BACKGROUND

The appropriate location for biopsy collection in ulcerative colitis is unknown.

OBJECTIVES

We aimed to determine the location for biopsy collection in the presence of ulcers which yields the highest histopathological score.

DESIGN AND METHODS

This prospective cross-sectional study enrolled patients with ulcerative colitis and ulcers in the colon. Biopsy specimens were obtained at the edge of the ulcer; at a distance of one open forceps (7-8 mm) from the ulcer edge; at a distance of three open forceps (21-24 mm) from the ulcer edge; further referred to as locations 1, 2 and 3 respectively. Histological activity was assessed using Robarts Histopathology Index and the Nancy Histological Index. Statistical analysis was performed using mixed effects models.

RESULTS

A total of 19 patients were included. Decreasing trends with distance from the ulcer edge ( P  < 0.0001) were observed. Biopsies procured from the edge of the ulcer (location 1) yielded a higher histopathological score compared to biopsies procured at locations 2 and 3 ( P  ≤ 0.001).

CONCLUSION

Biopsies from the ulcer edge yield higher histopathological scores than biopsies next to the ulcer. In clinical trials with histological endpoints, biopsies should be obtained from the ulcer edge (if ulcers are present) to reliably assess histological disease activity.

Integrated omic techniques and their genomic features for invasive weeds

Many emerging invasive weeds display rapid adaptation against different stressful environments compared to their natives. Rapid adaptation and dispersal habits helped invasive populations have strong diversity within the population compared to their natives. Advances in molecular marker techniques may lead to an in-depth understanding of the genetic diversity of invasive weeds. The use of molecular techniques is rapidly growing, and their implications in invasive weed studies are considered powerful tools for genome purposes. Here, we review different approach used multi-omics by invasive weed studies to understand the functional structural and genomic changes in these species under different environmental fluctuations, particularly, to check the accessibility of advance-sequencing techniques used by researchers in genome sequence projects. In this review-based study, we also examine the importance and efficiency of different molecular techniques in identifying and characterizing different genes, associated markers, proteins, metabolites, and key metabolic pathways in invasive and native weeds. Use of these techniques could help weed scientists to further reduce the knowledge gaps in understanding invasive weeds traits. Although these techniques can provide robust insights about the molecular functioning, employing a single omics platform can rarely elucidate the gene-level regulation and the associated real-time expression of weedy traits due to the complex and overlapping nature of biological interactions. We conclude that different multi-omic techniques will provide long-term benefits in launching new genome projects to enhance the understanding of invasive weeds' invasion process.

Histological Indices and Risk of Recurrence in Crohn's Disease: A Retrospective Study of a Cohort of Patients in Endoscopic Remission

BACKGROUND

Although histological healing is raising interest in ulcerative colitis to predict recurrence, its meaning in Crohn's disease (CD) remains unknown. We aimed to study the performances of different histological indices to predict recurrence of CD patients with mucosal healing.

METHODS

Crohn's disease patients with mucosal healing diagnosed between 2010 and 2018 were included if there was available clinical and endoscopical data. Nancy Histological index (NHI), Geboes score (GS), Robarts Histopathology index (RHI), Global Histological Disease Activity Score (GHAS), and Inflammatory Bowel Disease-Distribution Chronicity Activity score (IBD-DCA) were independently assessed by 3 pathologists.

RESULTS

Eighty-eight patients were included, of which 28 relapsed (32%) within 30.5 months. All 4 histological indices were associated with recurrence, with significant relapse risk (NHI, odds ratio [OR], 1.67; GHAS, OR, 2.33; RHI, OR, 1.19; GS, OR, 2.09; and IBD-DCA, OR, 2.14). Microscopic activity was significantly associated with relapse only with the IBD-DCA score. Predicting performances of all these scores were poor. Calibration curves indicate that the GHAS and IBD-DCA are the closest to the ideal predicted probability curve and thus could better predict recurrence than the other scores. Interobserver agreement varied from poor for GHAS (k = .39) to good for RHI (k = .68).

CONCLUSIONS

Histological scores are valuable indicators to predict recurrence. Histological assessment of activity seems insufficient to predict CD course with most of the score evaluated, highlighting the need for new indices or adaptation of actual scores to CD specificities.

Performance measures for colonoscopy in inflammatory bowel disease patients: European Society of Gastrointestinal Endoscopy (ESGE) Quality Improvement Initiative

The European Society of Gastrointestinal Endoscopy (ESGE) presents a short list of performance measures for colonoscopy in inflammatory bowel disease (IBD) patients. Current performance measures for colonoscopy mainly focus on detecting (pre)malignant lesions. However, these performance measures are not relevant for all colonoscopy indications in IBD patients. Therefore, our aim was to provide endoscopy services across Europe and other interested countries with a tool for quality monitoring and improvement in IBD colonoscopy. Eight key performance measures and one minor performance measure were recommended for measurement and evaluation in daily endoscopy practice.

Carboxymethyl Chitosan Oligosaccharide Holds Promise for Treatment of Stenosis Crohn's Disease

Crohn's disease (CD) is a chronic intestinal disturbance mediated by mucosal immune hyperactivity that is often associated with the formation of stenosis. No reliable solution to stenosis CD exists so far. Therefore, we generated carboxymethyl chitosan oligosaccharide (CMCOS) as a new promising therapy and investigate its efficacy in an improved rat CD model. CMCOS was synthesized by enzymatic hydrolysis, and its biosafety was evaluated in vivo. The rat model of stenosis CD was optimized by an orthogonal experiment of 75 or 100 mg/kg trinitrobenzenesulfonic acid (TNBS) in a 50 or 75% ethanol enema. The therapeutic efficacy of CMCOS on the rat model of stenosis CD was investigated and compared with the commercial drug 5-aminosalicylic acid over a 28 day period of disease progression. The rat model of stenosis CD was well established by intracolonic administration of 75 mg/kg TNBS in 75% ethanol. CMCOS significantly alleviated CD symptoms morphologically, hematologically, and pathologically, promoting functional recovery of intestinal epithelium in a dose-dependent manner. CMCOS reduced infiltrations of inflammatory cells by regulating the IL-17A/PPAR-γ pathway and reduced fibro-proliferation and fibro-degeneration of the colon tissue by downregulating the TGF-β1/WT1 pathway. 75 mg/kg TNBS in a 75% ethanol enema induces a rat model of stenosis CD suitable for preclinical pathology and pharmacological studies. The safety, antifibrosis, and functional repair performance of CMCOS make it a promising candidate for the treatment of stenosis CD.

Development and Validation of a Digital Analysis Method to Quantify CD3-immunostained T Lymphocytes in Whole Slide Images of Crohn's Disease Biopsies

The T-lymphocyte-mediated inflammation in Crohn's disease can be assessed by quantifying CD3-positive T-lymphocyte counts in colonic sections. We developed and validated a process to reliably quantify immunohistochemical marker-positive cells in a high-throughput setting using whole slide images (WSIs) of CD3-immunostained colonic and ileal tissue sections. In regions of interest (ROIs) and/or whole tissue sections of 40 WSIs from 36 patients with Crohn's disease, CD3-positive cells were quantified by an expert gastrointestinal pathologist (gold standard) and by image analysis algorithms developed with software from 3 independent vendors. Semiautomated quantification of CD3-positive cell counts estimated in 1 ROI per section were accurate when compared with manual analysis (Pearson correlation coefficient, 0.877 to 0.925). Biological variability was acceptable in digitally determined CD3-positive cell measures between 2 to 5 ROIs annotated on the same tissue section (coefficient of variation <25%). Results from computer-aided analysis of CD3-positive T lymphocytes in a whole tissue section and the average of results from 2 to 5 ROIs per tissue section lacked reliability (overestimation or underestimation and systematic bias), suggesting that absolute quantification of CD3-positive T lymphocytes in a whole tissue section may be more accurate. Semiautomated image analysis in WSIs demonstrated reproducible CD3-positive cell measures across 3 independent algorithms. A computer-aided digital image analysis method was developed and validated to quantify CD3-positive T lymphocytes in colonic and ileal biopsy sections from patients with Crohn's disease. Results support consideration of this digital analysis method for use in future Crohn's disease clinical studies.

ECCO Position on Harmonisation of Crohn's Disease Mucosal Histopathology

In inflammatory bowel disease [IBD], mucosal healing is a major therapeutic target and a reliable predictor of clinical course. However, endoscopic mucosal healing is not synonymous with histological healing, and the additional benefits of including histological remission as a target are unclear. In Crohn´s disease [CD], there are few studies highlighting the value of histological remission as a therapeutic target. Histological activity can persist in CD patients who are in endoscopic remission, and the absence of histological activity may be associated with lower relapse rates. Therefore, standardisation of procedures to evaluate CD histological activity is desirable. Topics that would benefit from standardisation and harmonisation include biopsy procedures, biopsy processing techniques, the content of histological scores, and the definitions of histological remission, histological response, and histological activity. In line with these needs, the European Crohn's and Colitis Organisation [ECCO] assembled a consensus group with the objective of developing position statements on CD histology based on published evidence and expert consensus. There was agreement that definitions of histological remission should include absence of erosion, ulceration, and mucosal neutrophils; that the absence of neutrophilic inflammation is an appropriate histological target in CD; that CD histological scores, such as the Global Histological Disease Activity Score, lack formal validation; and that histological scoring systems for ulcerative colitis, including the Geboes Score, Robarts Histopathology Index, and Nancy Histological Index, can be used for scoring intestinal biopsies in CD patients.

Histological Scores in Patients with Inflammatory Bowel Diseases: The State of the Art

The histological assessment has been advocated as a detailed and accurate measure of disease activity in inflammatory bowel diseases (IBD). In ulcerative colitis (UC), histological activity has been demonstrated to be associated with higher rates of relapse, prolonged corticosteroid use and long-term complications, even when endoscopic remission is achieved. Therefore, histological healing may represent a potential treatment target. Several histological scores have been developed and are available today. The Robarts histopathology index (RHI) and the Nancy index (NI) are the only two recommended by the European Crohn’s and Colitis Organization (ECCO) for use in patients with UC. Conversely, in Crohn’s disease (CD), the discontinuous nature of lesions has limited standardized histological assessment. Most of the available histological scoring systems in CD are complex and not validated. The aim of this review is to comprehensively summarize the latest evidence regarding histological scoring systems in IBD. We guide the reader through understanding the importance of an accurate microscopic evaluation using validated scoring systems, highlighting the strengths and pitfalls of each score. The priorities of future research needs are also addressed.

Treatment of Inflammatory Bowel Disease: A Comprehensive Review

Inflammatory bowel disease (IBD), as a global disease, has attracted much research interest. Constant research has led to a better understanding of the disease condition and further promoted its management. We here reviewed the conventional and the novel drugs and therapies, as well as the potential ones, which have shown promise in preclinical studies and are likely to be effective future therapies. The conventional treatments aim at controlling symptoms through pharmacotherapy, including aminosalicylates, corticosteroids, immunomodulators, and biologics, with other general measures and/or surgical resection if necessary. However, a considerable fraction of patients do not respond to available treatments or lose response, which calls for new therapeutic strategies. Diverse therapeutic options are emerging, involving small molecules, apheresis therapy, improved intestinal microecology, cell therapy, and exosome therapy. In addition, patient education partly upgrades the efficacy of IBD treatment. Recent advances in the management of IBD have led to a paradigm shift in the treatment goals, from targeting symptom-free daily life to shooting for mucosal healing. In this review, the latest progress in IBD treatment is summarized to understand the advantages, pitfalls, and research prospects of different drugs and therapies and to provide a basis for the clinical decision and further research of IBD.

Endoscopic tissue sampling - Part 2: Lower gastrointestinal tract. European Society of Gastrointestinal Endoscopy (ESGE) Guideline

1: ESGE suggests performing segmental biopsies (at least two from each segment), which should be placed in different specimen containers (ileum, cecum, ascending, transverse, descending, and sigmoid colon, and rectum) in patients with clinical and endoscopic signs of colitis.Weak recommendation, low quality of evidence. 2: ESGE recommends taking two biopsies from the right hemicolon (ascending and transverse colon) and, in a separate container, two biopsies from the left hemicolon (descending and sigmoid colon) when microscopic colitis is suspected.Strong recommendation, low quality of evidence. 3: ESGE recommends pancolonic dye-based chromoendoscopy or virtual chromoendoscopy with targeted biopsies of any visible lesions during surveillance endoscopy in patients with inflammatory bowel disease. Strong recommendation, moderate quality of evidence. 4: ESGE suggests that, in high risk patients with a history of colonic neoplasia, tubular-appearing colon, strictures, ongoing therapy-refractory inflammation, or primary sclerosing cholangitis, chromoendoscopy with targeted biopsies can be combined with four-quadrant non-targeted biopsies every 10 cm along the colon. Weak recommendation, low quality of evidence. 5: ESGE recommends that, if pouch surveillance for dysplasia is performed, visible abnormalities should be biopsied, with at least two biopsies systematically taken from each of the afferent ileal loop, the efferent blind loop, the pouch, and the anorectal cuff.Strong recommendation, low quality of evidence. 6: ESGE recommends that, in patients with known ulcerative colitis and endoscopic signs of inflammation, at least two biopsies be obtained from the worst affected areas for the assessment of activity or the presence of cytomegalovirus; for those with no evident endoscopic signs of inflammation, advanced imaging technologies may be useful in identifying areas for targeted biopsies to assess histologic remission if this would have therapeutic consequences. Strong recommendation, low quality of evidence. 7: ESGE suggests not biopsying endoscopically visible inflammation or normal-appearing mucosa to assess disease activity in known Crohn's disease.Weak recommendation, low quality of evidence. 8: ESGE recommends that adequately assessed colorectal polyps that are judged to be premalignant should be fully excised rather than biopsied.Strong recommendation, low quality of evidence. 9: ESGE recommends that, where endoscopically feasible, potentially malignant colorectal polyps should be excised en bloc rather than being biopsied. If the endoscopist cannot confidently perform en bloc excision at that time, careful representative images (rather than biopsies) should be taken of the potential focus of cancer, and the patient should be rescheduled or referred to an expert center.Strong recommendation, low quality of evidence. 10: ESGE recommends that, in malignant lesions not amenable to endoscopic excision owing to deep invasion, six carefully targeted biopsies should be taken from the potential focus of cancer.Strong recommendation, low quality of evidence.

Meta-analysis of gene expression disease signatures in colonic biopsy tissue from patients with ulcerative colitis

Publicly available ulcerative colitis (UC) gene expression datasets from observational studies and clinical trials include inherently heterogeneous disease characteristics and methodology. We used meta-analysis to identify a robust UC gene signature from inflamed biopsies. Eight gene expression datasets derived from biopsy tissue samples from noninflammatory bowel disease (IBD) controls and areas of active inflammation from patients with UC were publicly available. Expression- and meta-data were downloaded with GEOquery. Differentially expressed genes (DEG) in individual datasets were defined as those with fold change > 1.5 and a Benjamini–Hochberg adjusted P value < .05. Meta-analysis of all DEG used a random effects model. Reactome pathway enrichment analysis was conducted. Meta-analysis identified 946 up- and 543 down-regulated genes in patients with UC compared to non-IBD controls (1.2 and 1.7 times fewer up- and down-regulated genes than the median of the individual datasets). Top-ranked up- and down-regulated DEG were LCN2 and AQP8. Multiple immune-related pathways (e.g., ‘Chemokine receptors bind chemokine’ and ‘Interleukin-10 signaling’) were significantly up-regulated in UC, while ‘Biological oxidations’ and ‘Fatty acid metabolism’ were downregulated. A web-based data-mining tool with the meta-analysis results was made available (https://premedibd.com/genes.html). A UC inflamed biopsy disease gene signature was derived. This signature may be an unbiased reference for comparison and improve the efficiency of UC biomarker studies by increasing confidence for identification of disease-related genes and pathways.

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

BACKGROUND

Targeting histological remission or response in Crohn's disease (CD) is not recommended in clinical practice guidelines or as an outcome in clinical trials due to uncertainties regarding index validity and prognostic relevance.

AIMS

To conduct a modified RAND/University of California Los Angeles appropriateness process with the goal of producing a framework to standardise histological assessment of CD activity in clinical trials.

METHODS

A total of 115 statements generated from literature review and expert opinion were rated on a scale of 1-9 by a panel of 11 histopathologists and 6 gastroenterologists. Statements were classified as inappropriate, uncertain or appropriate based upon the median panel rating and degree of disagreement.

RESULTS

The panellists considered it important to measure histological activity in clinical trials to determine efficacy and that absence of neutrophilic inflammation is an appropriate histological target. They were uncertain whether the Global Histological Activity Score was an appropriate instrument for measuring histological activity. The Geboes Score and Robarts Histopathology Index were considered appropriate. Two biopsies from five segments should be biopsied, and the colon and the ileum should be analysed separately for all indices. Endoscopic mucosal appearance should guide biopsy procurement site with biopsies taken from the ulcer edge, or the most macroscopically inflamed area in the absence of ulcers.

CONCLUSION

We evaluated the appropriateness of items for assessing histological disease activity in CD clinical trials. These items will be used to develop a novel histological index.

ECCO Position Paper: Harmonization of the Approach to Ulcerative Colitis Histopathology

Currently, the main targets of drug therapy for ulcerative colitis [UC] are endoscopic and clinical remission. However, there is active discussion about the additional advantages of including histological remission as a target. Accumulating evidence indicates that microscopic activity persists in endoscopically quiescent UC, that histological changes may lag behind clinical remission after treatment, and that absence of histological activity predicts lower rates of relapse, hospitalization, surgery and subsequent neoplasia. Obtaining useful information from mucosal biopsies in this setting depends on accurate and consistent evaluation of histological features. However, there is no standardization of biopsy procedures, histological sample processing technique or histological scoring systems, and there is no agreement on the definitions of histological remission, response or activity. Accordingly, a consensus expert panel convened by the European Crohn's and Colitis Organisation [ECCO] reviewed the literature and agreed a number of position statements regarding harmonization of UC histopathology. The objective was to provide evidence-based guidance for the standardization and harmonization of procedures, definitions and scoring systems for histology in UC, and to reach expert consensus where possible. We propose the absence of intraepithelial neutrophils, erosion and ulceration as a minimum requirement for the definition of histological remission. For randomized control trials we recommend the use of the Robarts histopathology index [RHI] or the Nancy index [NI]. For observational studies or in clinical practice we recommend the use of the NI. To predict the risk of future neoplasia in UC, cumulative histological scores over time are more useful than single scores.

Treat to target or 'treat to clear' in inflammatory bowel diseases: one step further?

INTRODUCTION

Inflammatory bowel diseases (IBD) are chronic and progressive diseases. Long-term complications are demolitive surgery and colon-rectal cancer. A 'treat to target' strategy, in which the treatment aims to achieve objective outcomes, has already been introduced in the management of chronic conditions as rheumatic diseases. This approach is emerging as suitable for ulcerative colitis and Crohn's disease. Targets are predefined therapeutic goals demonstrated to prevent end-organ dysfunction. An optimization or switch of therapy is considered depending on the target's achievement, with regular monitoring.

AREAS COVERED

According to the Selecting Therapeutic Targets in Inflammatory Bowel Disease (STRIDE) indications, mucosal healing and clinical remission are the main targets in IBDs. Histological remission is increasingly being considered as a novel target and has given rise to the new concept of 'disease clearance' which includes clinical, endoscopic and microscopic remission. We aim to review current evidence on the treat-to-target strategy in comparison to a stricter treat-to-clear in the IBD field.

EXPERT OPINION

Prospective studies on treat-to-target algorithm are sparse; a treat-to-clear approach is desirable but far from adoption in the daily practice and clinical trials. The ultimate goals of a treat-to-clear strategy differ in UC and in CD, including histological healing and transmural healing, respectively.

Defining the Path Forward for Biomarkers to Address Unmet Needs in Inflammatory Bowel Diseases

Despite major advances in the inflammatory bowel diseases field, biomarkers to enable personalized and effective management are inadequate. Disease course and treatment response are highly variable, with some patients experiencing mild disease progression, whereas other patients experience severe or complicated disease. Periodic endoscopy is performed to assess disease activity; as a result, it takes months to ascertain whether a treatment is having a positive impact on disease progression. Minimally invasive biomarkers for prognosis of disease course, prediction of treatment response, monitoring of disease activity, and accurate diagnosis based on improved disease phenotyping and classification could improve outcomes and accelerate the development of novel therapeutics. Rapidly developing technologies have great potential in this regard; however, the discovery, validation, and qualification of biomarkers will require partnerships including academia, industry, funders, and regulators. The Crohn's & Colitis Foundation launched the IBD Biomarker Summit to bring together key stakeholders to identify and prioritize critical unmet needs; prioritize promising technologies and consortium approaches to address these needs; and propose harmonization approaches to improve comparability of data across studies. Here, we summarize the outcomes of the 2018 and 2019 meetings, including consensus-based unmet needs in the clinical and drug development context. We highlight ongoing consortium efforts and promising technologies with the potential to address these needs in the near term. Finally, we summarize actionable recommendations for harmonization, including data collection tools for improved consistency in disease phenotyping; standardization of informed consenting; and development of guidelines for sample management and assay validation. Taken together, these outcomes demonstrate that there is an exceptional alignment of priorities across stakeholders for a coordinated effort to address unmet needs of patients with inflammatory bowel diseases through biomarker science.

Prognostic influence of tumor microenvironment after hypofractionated radiation and surgery for mesothelioma

OBJECTIVE

Cytotoxic CD8+ tumor infiltrating lymphocytes (TILs) can contribute to the benefit of hypofractionated radiation, but programmed cell death pathways (programmed cell death 1 and programmed cell death ligand 1 [PD-1/PD-L1]) may provide a mechanism of tumor immune escape. We therefore reviewed the influence of PD-1/PD-L1 and CD8+ TILs on survival after accelerated hypofractionated hemithoracic radiation followed by extrapleural pneumonectomy for malignant pleural mesothelioma (MPM).

METHODS

Sixty-nine consecutive patients undergoing the protocol of Surgery for Mesothelioma after Radiation Therapy (SMART) between November 2008 and February 2016 were analyzed for the presence of PD-L1 on tumor cells, PD-1 on inflammatory cells, and CD8+ TILs. Comparison was made with a cohort of patients undergoing extrapleural pneumonectomy after induction chemotherapy (n = 14) and no induction (n = 2) between March 2005 and October 2008. PD-L1 expression on tumor cells ≥1% was considered positive. CD8+ TILs and PD-1 expression were scored as a percentage of positive cells.

RESULTS

PD-L1 was negative in 75% of MPM after completion of SMART. CD8+ TILs ranged between 0.24% and 8.47% (median 2%). CD8+ TILs ≥2% was associated with significantly better survival in epithelioid MPM (median survival 3.7 years vs 2.3 years in CD8+ TILs <2%; P = .02). PD-L1 positivity was associated with worse survival in biphasic MPM (median survival, 0.4 years vs 1.5 years in biphasic PD-L1 negative tumors; P = .07) after SMART. Multivariate analysis demonstrated that epithelioid MPM, nodal disease, and CD8+ TILs were independent predictors of survival after SMART.

CONCLUSIONS

The influence of tumor microenvironment on survival differs between epithelioid and nonepithelioid MPM. CD8+ TILs is an independent factor associated with better survival in epithelioid MPM treated with SMART.

Endoscopic, Radiologic, and Histologic Healing With Vedolizumab in Patients With Active Crohn's Disease

BACKGROUND & AIMS

Vedolizumab is a gut-selective monoclonal antibody for the treatment of moderately to severely active Crohn's disease (CD). We performed a prospective study of endoscopic, radiologic, and histologic healing in patients with CD who received vedolizumab therapy.

METHODS

We performed a phase 3b, open-label, single-group study of 101 patients with at least 3 months of active CD (a CD Activity Index [CDAI] score of 220-450, a simple endoscopic score for CD [SES-CD] of 7 or more, 1 or more mucosal ulcerations [identified by endoscopy], and failure of conventional therapy) from March 2015 through December 2017. Among the patients enrolled, 54.5% had previous failure of 1 or more tumor necrosis factor (TNF) antagonists and 44.6% had severe endoscopic disease activity (SES-CD scores above 15) at baseline. Participants received vedolizumab (300 mg intravenously) at weeks 0, 2, and 6, and then every 8 weeks thereafter, for 26 weeks (primary study) or 52 weeks (substudy, 56 patients). The primary endpoint at week 26 was endoscopic remission (SES-CD score of 4 or less); other endpoints included endoscopic response (50% reduction in SES-CD), radiologic remission (magnetic resonance index of activity score below 7), and histologic response (modified global histologic disease activity score of 4 or less).

RESULTS

At week 26, 11.9% of patients were in endoscopic remission (95% confidence interval [CI] 6.3-9.8); at week 52, 17.9% of the patients were in endoscopic remission (95% CI 8.9-30.4). Higher proportions of patients naïve to TNF antagonists achieved endoscopic remission than patients with TNF-antagonist-failure at weeks 26 and 52. Higher proportion of patients with moderate CD (SES-CD scores, 7-15) achieved endoscopic remission at weeks 26 and 52 than patients with severe CD (SES-CD scores above 15). The proportion of patients with complete mucosal healing increased over time, with greater rates of healing in the colon than in the ileum. Remission was detected by magnetic resonance enterography in 21.9% of patients at week 26 (95% CI 9.3-40.0) and in 38.1% at week 52 (95% CI 18.1-61.6). At week 26, 24.4% of patients had a histologic response in the colon (95% CI 15.3-35.4) and 28.3% of patients had a histologic response in the ileum (95% CI 17.5-41.4). At week 52, 20.5% of patients had a histologic response in the colon (95% CI 9.8-35.3) and 34.3% of patients had a histologic response in the ileum (95% CI 19.1-52.2). There were no notable safety issues, including worsening of extraintestinal manifestations.

CONCLUSIONS

In a phase 3b trial, we found that 26 and 52 weeks of treatment with vedolizumab (300 mg, at weeks 0, 2, and 6, and then every 8 weeks thereafter) induces endoscopic, radiologic, and histologic healing in patients with moderately to severely active CD. ClinicalTrials.gov no: NCT02425111.