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

18β-Glycyrrhetinic acid from Glycyrrhiza Uralensis protects colonic epithelium in ulcerative colitis by activating Wnt/β-catenin pathway to restore tight junction

BACKGROUND

Ulcerative colitis (UC) is a chronic inflammatory bowel disease characterized by persistent inflammation of the colon. Glycyrrhiza uralensis extract (ULE), a traditional medicinal plant extract, is globally recognized for its anti-inflammatory and gastrointestinal therapeutic effects. However, the precise mechanisms underlying the therapeutic benefits of ULE in UC management remain poorly understood.

PURPOSE

This study aimed to elucidate the pharmacological effects of ULE and its primary active constituent, 18β-glycyrrhetinic acid (18β-GA), on the colonic epithelium in UC rat models.

STUDY DESIGN AND METHODS

We employed a 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced UC rat model and a TNBS-LPS-induced UC Caco-2 cell model to explore the protective mechanisms of ULE and 18β-GA. The methodologies included UPLC-Q/TOF-MS chemical analysis in chemico, network pharmacological screening in silico, histopathological and flow cytometry evaluations in vivo, and molecular biological validation in vitro.

RESULTS

ULE significantly alleviated UC symptoms in rats, including weight loss, diarrhea, and rectal bleeding, particularly at a dosage of 100 mg/kg. Network pharmacology and transcriptomic analyses identified the Wnt pathway as a pivotal hub linking inflammation, epithelial proliferation, and tight junction integrity. ULE treatment reduced apoptosis (from 13.24% to 8.34%), CD3+ T cells (from 13% to 6.04%), and CD45RA+ B cells (from 7.23% to 1.67%) in colonic tissues. Furthermore, ULE restored tight junction protein expression, notably increasing Occludin (2.5×) and ZO-1 (5.3×). Similarly, 18β-GA activated the Wnt/β-catenin signaling pathway and elevated tight junction protein expression, thereby protecting against UC-like damage in the Caco-2 cell model. These protective effects were potentiated by the Wnt pathway agonist SKL2001 and diminished by the antagonist IWR-1.

CONCLUSION

ULE and its active constituent, 18β-GA, exhibit protective effects against TNBS-induced colonic epithelial injury and tight junction protein disruption by upregulating the Wnt/β-catenin signaling pathway, making them promising therapeutic candidates for UC management.

Histologic and Endoscopic Findings Are Highly Correlated in a Prospective Cohort of Patients With Inflammatory Bowel Diseases

BACKGROUND AND AIMS

The advantages of endoscopic vs histologic assessments of inflammation in inflammatory bowel disease remain unclear. We compared endoscopic and histologic inflammation in a prospective cohort. Furthermore, in patients with discordant findings, we compared the ability of endoscopy vs histology to predict disease course.

METHODS

Ulcerative colitis (UC) or Crohn's disease (CD) patients underwent routine colonoscopies with intestinal biopsies, which included ratings of inflammation severity. Tetrachoric correlation analysis between the endoscopic and histologic inflammation ratings was performed. In postsurgical CD patients, major adverse outcomes (MAOs) were recorded.

RESULTS

The analysis included 749 patients (60.2% CD patients), with 2807 biopsied segments. We found high concordance between endoscopist and pathologist inflammation ratings (0.84, 95% confidence interval, 0.81-0.87, p < 0.0001). Only 12.5% of biopsied segments exhibited microscopic inflammation without endoscopic inflammation. Neo-terminal ileum (neo-TI) biopsies exhibited the highest discordance; UC colonic biopsies had the highest concordance. Postsurgical CD patients who completed the 48-month follow-up (n = 138) were included in the survival analysis. The probability of MAO-free survival was significantly higher in patients with a Rutgeerts score of i0 at baseline than in those with higher scores. Microscopic inflammation in the neo-TI did not predict a higher risk of MAOs (p = 1.00).

CONCLUSIONS

In a real-world setting, endoscopic inflammation predicted histologic inflammation with high accuracy. In patients with a Rutgeerts score of i0, microscopic inflammation in neo-TI biopsies did not predict more aggressive disease behavior over the next 4 years. These results have implications for the design of clinical trials, suggesting the use of endoscopic healing as an endpoint.

Histological healing in IBD: Ready for prime time?

The main target of treatment in ulcerative colitis and Crohn's disease is to achieve a complete so-called mucosal healing. Various definitions of mucosal healing are available in literature, and the most recent ones include a combination of endoscopic and histological remission. However, the assessment of a complete histological remission is not always univocal. Absence of neutrophil infiltration in the lamina propria, together with neutrophil-mediated mucosal injuries in crypt and surface epithelium, is considered an important element to define histological remission. Although several histological scoring systems have been proposed to differentiate active vs quiescent disease and to evaluate the therapeutic efficacy, most of them are subjective and complex to employ in the daily diagnostic routine. For this reason, to simplify histologic scoring attempts have been made by introducing simplified scores, based on the evaluation of neutrophils and their mucosal localization. Artificial intelligence models are also being developed to standardize histological assessment of mucosal healing, and new biomarkers, such as claudin- 2, are emerging to simplify this latter aspect.

The Role of Histology Alongside Clinical and Endoscopic Evaluation in the Management of IBD-A Narrative Review

Inflammatory bowel diseases (IBD), including Crohn's disease (CD) and ulcerative colitis (UC), are chronic inflammatory conditions requiring continuous monitoring. Today, endoscopy is the gold standard for assessing disease activity, with histological evaluation providing additional insights. Studies suggest that persistent histological inflammation, despite endoscopic remission, may be associated with a higher risk of relapse in UC, suggesting its role in treatment decisions. In CD, histological assessment is limited by its patchy nature, transmural inflammation and lack of validated scoring systems. Few retrospective studies with conflicting results have examined the prognostic value of histological remission in CD, and its role in predicting long-term outcomes remains unclear. This narrative review aims to summarize and discuss the available evidence regarding the additional value of histological assessment in IBD management. In UC, the ongoing VERDICT study is expected to provide evidence on the impact of incorporating histological remission as a treatment target compared to a strategy based on clinical and endoscopic activity. Recently published interim results indicate that targeting histological remission does not lead to better clinical/biochemical disease activity. Thus, while patients achieving histological healing are associated with better outcomes, the question arises whether achieving histological remission is an intrinsic (biological) characteristic of the patient and indicator of an easier to treat patient group or a result of more effective therapy.

Novel outcomes in inflammatory bowel disease

Inflammatory bowel diseases (IBD), Crohn's disease (CD), and ulcerative colitis (UC) are lifelong chronic, relapsing, and remitting conditions that culminate in disease progression in many patients. Effective management of CD and UC requires consideration of both short- and long-term treatment outcomes. Historically, short-term outcomes such as clinical and endoscopic remission and symptom relief have been evaluated in clinical trials. With the expansion of treatments targeting underlying disease pathophysiology, there is the opportunity to develop management strategies that improve disease control and patients' lives in both the short and the long term. Researchers have been examining novel outcomes for assessing the efficacy of CD and UC treatments that are important to patients, and also those that go beyond symptomatic improvements or clinical remission. These include new patient-reported outcomes for symptoms, as well as transmural/histological healing and disease clearance that can be more reflective of deeper remission states and disease modification. This review analyses published clinical studies involving patients with UC and CD treated with biologics or small molecule therapies. It highlights novel IBD endpoints employed in published clinical trials and discusses their likely value for assessing disease activity and disease modification, and as predictors of reduced risk of complications and morbidities.

Claudin-2 simplifies histological assessment of activity/remission of ulcerative colitis in real-life daily practice

OBJECTIVES

Mucosal healing, and in particular histological mucosal healing, represents the new frontier as a treatment goal for inflammatory bowel diseases. However, the assessment of mucosal healing is presently somewhat limited by the numerous pathological scores available, and the lack of a global consensus on how to best assess it. For this reason, the availability of a simple and rapid test to evaluate the inflammatory state of the mucosa after treatment would be useful, especially for the daily routine.

METHODS

To exploit the above purpose, we evaluated the possible usefulness of antibodies against claudin-2, a protein of intestinal epithelium tight junctions, as a possible test to assess the presence of activity in ulcerative colitis following treatment. Biopsies from 28 patients with distal localization of the disease and clinical and endoscopic remission were tested for claudin-2 reactivity.

RESULTS

Claudin-2 reactivity was always negative in noninvolved segments and displayed a variable staining intensity in concordance with the histological activity. There was a highly significant ( P  < 0.0001) correlation between histological score and claudin-2 expression in the colonic segments involved (descending, sigmoid colon, and rectum).

CONCLUSIONS

Our results suggest that the use of claudin-2 in the routine daily practice could simplify and corroborate the results of current histological evaluations, especially in clinical practice and posttreatment follow-up.

Rediscovering histology - the application of artificial intelligence in inflammatory bowel disease histologic assessment

Integrating artificial intelligence (AI) into histologic disease assessment is transforming the management of inflammatory bowel disease (IBD). AI-aided histology enables precise, objective evaluations of disease activity by analysing whole-slide images, facilitating accurate predictions of histologic remission (HR) in ulcerative colitis and Crohn's disease. Additionally, AI shows promise in predicting adverse outcomes and therapeutic responses, making it a promising tool for clinical practice and clinical trials. By leveraging advanced algorithms, AI enhances diagnostic accuracy, reduces assessment variability and streamlines histological workflows in clinical settings. In clinical trials, AI aids in assessing histological endpoints, enabling real-time analysis, standardising evaluations and supporting adaptive trial designs. Recent advancements are further refining AI-aided digital pathology in IBD. New developments in multimodal AI models integrating clinical, endoscopic, histologic and molecular data pave the way for a comprehensive approach to precision medicine in IBD. Automated assessment of intestinal barrier healing - a deeper level of healing beyond endoscopic and HR - shows promise for improved outcome prediction and patient management. Preliminary evidence also suggests that AI applied to colitis-associated neoplasia can aid in the detection, characterisation and molecular profiling of lesions, holding potential for enhanced dysplasia management and organ-sparing approaches. Although challenges remain in standardisation, validation through randomised controlled trials and ethical considerations. AI is poised to revolutionise IBD management by advancing towards a more personalised and efficient care model, while the path to full clinical implementation may be lengthy. However, the transformative impact of AI on IBD care is already shining through.

Artificial intelligence to revolutionize IBD clinical trials: a comprehensive review

Integrating artificial intelligence (AI) into clinical trials for inflammatory bowel disease (IBD) has potential to be transformative to the field. This article explores how AI-driven technologies, including machine learning (ML), natural language processing, and predictive analytics, have the potential to enhance important aspects of IBD trials-from patient recruitment and trial design to data analysis and personalized treatment strategies. As AI advances, it has potential to improve long-standing challenges in trial efficiency, accuracy, and personalization with the goal of accelerating the discovery of novel therapies and improve outcomes for people living with IBD. AI can streamline multiple trial phases, from target identification and patient recruitment to data analysis and monitoring. By integrating multi-omics data, electronic health records, and imaging repositories, AI can uncover molecular targets and personalize trial strategies, ultimately expediting drug development. However, the adoption of AI in IBD clinical trials encounters significant challenges. These include technical barriers in data integration, ethical concerns regarding patient privacy, and regulatory issues related to AI validation standards. Additionally, AI models risk producing biased outcomes if training datasets lack diversity, potentially impacting underrepresented populations in clinical trials. Addressing these limitations requires standardized data formats, interdisciplinary collaboration, and robust ethical frameworks to ensure inclusivity and accuracy. Continued partnerships among clinicians, researchers, data scientists, and regulators will be essential to establish transparent, patient-centered AI frameworks. By overcoming these obstacles, AI has the potential to enhance the efficiency, equity, and efficacy of IBD clinical trials, ultimately benefiting patient care.

Responsiveness of different disease activity indices in moderate-to-severe ulcerative colitis

BACKGROUND

Clinical, endoscopic, histological, and composite instruments are currently used to measure disease activity in patients with ulcerative colitis (UC). We compared the responsiveness of the Mayo Clinic score (MCS), modified MCS (mMS; excluding physician global assessment), partial MCS (pMS; MCS without endoscopic subscore), Robart's Histopathology Index (RHI), and UC-100 score to change after ustekinumab treatment in patients with moderately to severely active UC.

METHODS

Post hoc analysis of the phase 3 UNIFI induction trial (ClinicalTrials.gov: NCT02407236) was conducted. Participants with moderately to severely active UC were randomized to receive ustekinumab or placebo. Treatment assignment was the criterion to assess responsiveness, which was quantified using the probability of a treated participant having a larger change in score than a placebo participant, termed the win probability (WinP), and estimated using nonparametric methods.

FINDINGS

The UC-100 score demonstrated large responsiveness (WinP 0.72 [95% confidence interval: 0.66-0.78]), and the MCS (0.68 [0.62-0.73]), mMS (0.69 [0.63-0.75]), and pMS (0.65 [0.59-0.71]) demonstrated similar effect sizes. Of the component items of the Mayo score, the endoscopic subscore (WinP 0.76 [0.69-0.82]) and the stool frequency subscore (WinP 0.74 [0.69-0.79]) were the most responsive. The Inflammatory Bowel Disease Questionnaire (IBDQ) quality-of-life questionnaire was also responsive (WinP 0.78 [0.72-0.82]).

CONCLUSIONS

UC disease activity indices are similarly responsive. Depending on the treatment setting, time point of evaluation, and feasibility of measurement, different scores may be used to demonstrate response. These results support the use of mMS as a composite primary endpoint, incorporating both patient-reported and endoscopic outcome measures. The UC-100 score may be more appropriate in settings that also routinely incorporate histological evaluation.

FUNDING

There is no funding for this study.

The Potential of Molecular Remission: Tissue Neutrophil Elastase Is Better Than Histological Activity for Predicting Long-Term Relapse in Patients With Ulcerative Colitis in Endoscopic Remission

BACKGROUND

Growing interest exists in deep remission, beyond clinical and endoscopic remission, to enhance long-term prognosis in patients with ulcerative colitis (UC). Our study aimed to evaluate the risk of relapse according to tissue expression levels of calprotectin and neutrophil elastase (NE) in patients with quiescent UC.

METHODS

Rectal biopsies were performed on 218 patients with UC in clinical and endoscopic remission. Histological activity was prospectively scored using the Robarts Histological Index. Tissue calprotectin and NE levels were evaluated using immunohistochemistry. Optimal tissue calprotectin and NE cutoffs for relapse were determined using log-rank analysis. Cox proportional hazard analyses evaluated relapse risk factors.

RESULTS

Tissue calprotectin and NE levels were significantly higher in patients with histological activity than in those in histological remission (P < .001). The optimal cutoffs of tissue calprotectin and NE for relapse were 10.61 and 22.08 per mm2, respectively. The 3-year clinical relapse risk was significantly lower in the low-tissue NE group than in the high-tissue NE group (P = .009); however, it did not differ between the low- and high-tissue calprotectin group (P = .094). In multivariate analyses, a low level of tissue NE expression was independently associated with a lower risk of 3-year clinical relapse (adjusted hazard ratio = 0.453, 95% confidence interval = 0.225-0.911, P = .026), unlike histological index and tissue calprotectin.

CONCLUSIONS

In patients with UC who have achieved clinical and endoscopic remission, tissue expression of NE is a better predictor of long-term relapse than histological activity.

How Artificial Intelligence Will Transform Clinical Care, Research, and Trials for Inflammatory Bowel Disease

Artificial intelligence (AI) refers to computer-based methodologies that use data to teach a computer to solve pre-defined tasks; these methods can be applied to identify patterns in large multi-modal data sources. AI applications in inflammatory bowel disease (IBD) includes predicting response to therapy, disease activity scoring of endoscopy, drug discovery, and identifying bowel damage in images. As a complex disease with entangled relationships between genomics, metabolomics, microbiome, and the environment, IBD stands to benefit greatly from methodologies that can handle this complexity. We describe current applications, critical challenges, and propose future directions of AI in IBD.

Intestinal histopathology in pediatric PSC-IBD: Characterization of phenotype and assessment of the Nancy Index

OBJECTIVES

We aimed to characterize the histologic gut phenotype of pediatric primary sclerosing cholangitis (PSC)-associated inflammatory bowel disease (IBD) against non-PSC colitis, and to assess Nancy Index (NI) performance in pediatric PSC-IBD.

METHODS

Single-center retrospective cohort study including children diagnosed with PSC-IBD or non-PSC colitis (ulcerative colitis [UC] or IBD-unclassified) from 2000 to 2018, with diagnostic intestinal biopsies. Biopsies were re-reviewed by two independent pathologists who assessed microscopic disease distribution, NI scores, and specific histological features in the right and left colons, overall and stratified by endoscopic severity (moderate-severe vs. no more than mild). We examined NI inter-rater reliability with Fleiss' weighted (quadratic) kappa and NI construct validity against global endoscopic severity (Spearman correlation) and clinical outcomes (logistic regression).

RESULTS

Fifty children with PSC-IBD and 81 colitis controls were included. Histologically, pancolitis (84% vs. 55%), right colon-predominant colitis (48% vs. 3%), and backwash ileitis (53% vs. 12%) (all p < 0.01) were significantly more common in PSC-IBD; histologic rectal sparing occurred at similar rates (6% vs. 10%, p = 0.54). Lamina propria-predominant neutrophils, prominent eosinophilic infiltration (left colon), and surface villiform change (right colon) were more common in PSC-IBD than colitis controls (p < 0.01). NI showed excellent inter-rater reliability (kappa > 0.9) and correlated moderately with global endoscopic severity but poorly with clinical activity in PSC-IBD.

CONCLUSIONS

Pediatric PSC-IBD has a distinct histologic phenotype that largely mirrors the endoscopic phenotype in distribution and includes a greater frequency of features not included in conventional UC histologic activity indices. Future work should investigate whether a PSC-IBD-specific index incorporating these features is warranted.

The Future of Clinical Trials in Inflammatory Bowel Disease

The medical management of inflammatory bowel disease (IBD) has been transformed over the past few decades by the approval of multiple classes of advanced therapies and the integration of more targeted treatment strategies for Crohn's disease and ulcerative colitis. These changes have been driven by an increasing number of pivotal randomized controlled trials, which have grown in size and complexity over time. Several landmark studies that are anticipated to change current IBD management paradigms have recently been completed or are on-going, including the first head-to-head biologic trials, advanced combination treatment trials, therapeutic strategy and treatment target trials, and multiple phase 3 registrational programs of novel compounds. Despite these advances, the future of IBD trials also faces major challenges with respect to cost, feasibility, and recruitment. Accordingly, innovative methods for early and late phase randomized controlled trials must be adopted. In this review, we provide a comprehensive overview of the evolution of modern IBD trials, discuss methods for improving trial efficiency in early and late phase development, and provide insights into the interpretation and implications of these data for clinical care.

Histological scores are poor predictors of short term outcomes in acute severe ulcerative colitis: An observational study

BACKGROUND

The role of various histologic scores in predicting outcomes in acute severe ulcerative colitis (ASUC) is unexplored.

METHODS

Consecutive patients of ASUC undergoing sigmoidoscopy and histological assessment by two independent pathologists for Simplified Geboes score (SGS), Robarts Histopathology Index (RHI) and Nancy histological index (NHI)] were included. Primary outcome was the role of histology in predicting need for second-line therapy or colectomy.

RESULTS

Of 82 patients with ASUC (mean age: 36 years, males 47.5 %), non-response to steroids was observed in 27 (32.9 %) of cases. Sixteen patients required second-line drug therapy and 8 required colectomy. There was no significant association between the need for second-line therapy or colectomy and the baseline histological scores [NHI (p = 0.61), SGS (p = 0.116) and RHI (p = 0.109)]. All three scores performed poorly to predict the need for second-line treatment or colectomy within 28 days. There was no significant association between histological scores and steroid response (NHI (p = 0.796), SGS (p = 0.57) and RHI (p = 0.941)]. All three scores had a strong positive correlation observed between each other but not with endoscopic Mayo score.

CONCLUSION

The three histologic scores (SGS, RHI and NHI) performed poorly in prediction of need for second-line treatment or colectomy in ASUC. Future studies should study the impact of histologic assessment on long term outcomes in ASUC.

Interpreting modern randomized controlled trials of medical therapy in inflammatory bowel disease

Treatment options for the medical management of inflammatory bowel disease (IBD) have expanded substantially over the past decade. Multiple classes of advanced therapies, including both monoclonal antibodies and novel oral small molecules, are now available for the treatment of moderately-to-severely active Crohn's disease and ulcerative colitis, highlighted by the approvals of the first IL23p19 antagonists, selective Janus kinase inhibitors and sphingosine-1-phosphate receptor modulators. These advances have been accompanied by the identification of novel targets and the rapid growth in both the number and size of IBD clinical trials. Over a dozen landmark randomized controlled trials (RCTs) have been completed in the past 5 years, including the first head-to-head biologic trials, the first combination biologic studies, and multiple phase III registrational trials of novel compounds with new co-primary and composite end points that will change the treatment landscape for years to come. Importantly, the methodology of RCTs in IBD has evolved substantially, with new trial designs, evaluation of unique patient populations, and different types of efficacy and safety end points being key innovations. In this Review, we provide a comprehensive evaluation of how modern RCTs of IBD medical therapies have evolved and the implications for their appraisal that will help guide the application of these data to clinical practice.

An evaluation of mirikizumab for the treatment of ulcerative colitis

INTRODUCTION

Treatment of ulcerative colitis (UC) aims to reduce symptoms and complications by decreasing intestinal inflammation. A proportion of patients do not respond to, do not tolerate, or are inappropriate candidates for current therapies. Interleukin (IL)-23 is a therapeutic target and mirikizumabis the first p19-targeted IL-23 antibody approved for the treatment of moderately to severely active UC.

AREAS COVERED

This review summarizes the pro-inflammatory effects of IL-23 and outlines the pharmacokinetics of mirikizumab. It provides a synopsis of the available phase II and phase III evidence for the efficacy and safety of mirikizumab in UC.

EXPERT OPINION

The mirikizumab clinical development program demonstrated its superiority over placebo and its favorable safety profile in the treatment of UC. Its positioning in therapeutic algorithms remains to be fully understood but mirikizumab has proven efficacy in both advanced therapy (AT)-naïve and AT-experienced patients. The inclusion in the license of extended induction for non-responders as well as rescue intravenous dosing allows for flexibility in patient with limited primary response and secondary loss of response.

Absence of Paneth Cell Metaplasia to Predict Clinical Relapse in Ulcerative Colitis with Endoscopically Quiescent Mucosa

BACKGROUND

Paneth cells play multiple roles in maintaining intestinal homeostasis. However, the clinical role of Paneth cell metaplasia (PCM) in ulcerative colitis (UC) remains unclear. We aimed to investigate the relationship between PCM and relapse in patients with UC and compare the usefulness of PCM with other histological indexes, including mucin depletion (MD) and basal plasmacytosis (BP).

METHODS

Patients with UC in clinical remission (CR) who underwent colonoscopy to confirm a Mayo endoscopic subscore (MES) ≦1 with biopsies from the distal colon were enrolled into this retrospective cohort study. Biopsy samples were evaluated for histological findings of PCM, MD, and BP. Clinical relapse was defined as partial Mayo score ≧3 or medication escalation. Multivariate analysis was performed to determine independent predictors of relapse among the three histological findings, MES, and patient background, and relapse prediction models were generated.

RESULTS

Eighty-three patients were enrolled in this study (MES 0, n = 47; MES 1, n = 36). The number of PCM cases was significantly higher in patients with prolonged CR than that in those with relapse (p = 0.01). Multivariate analysis showed that the absence of PCM and MD were related to relapse in all the patients. In patients with MES 1, the absence of PCM was the only risk factor significantly and independently associated with relapse (hazard ratio, 4.51 [1.15-17.7]; p = 0.03).

CONCLUSION

The absence of PCM was a histological risk factor for relapse in patients with MES 1, implying a protective role for PCM in remission and a new index for mucosal healing.

The evolving understanding of histology as an endpoint in ulcerative colitis

A therapeutic goal for patients with ulcerative colitis (UC) is deep remission including clinical remission and mucosal healing. Mucosal healing was previously defined by endoscopic appearance, but recent studies demonstrate that histological improvements can minimize the risks of experiencing clinical relapse after achieving endoscopic remission, and there is growing interest in the value and feasibility of histological targets of treatment in inflammatory bowel disease, and specifically UC. In this review article, we identify remaining challenges and discuss an evolving role of histology in the management of UC.

Comparison of the Effectiveness of Vedolizumab and Ustekinumab in Patients with Ulcerative Colitis: A Real-World Retrospective Study

Ulcerative colitis (UC) is a chronic inflammatory disorder of the large intestine. Data on the comparative effectiveness of biological therapies such as vedolizumab (VDZ) and ustekinumab (UST) remain limited. This retrospective study compared the effectiveness and safety of VDZ and UST in UC patients. Between November 2018 and November 2023, 106 patients were included: 64 received VDZ and 42 received UST. Bio-failure was significantly higher (p = 0.005) in the UST group versus the VDZ group. The remission rates at 6, 22, and 54 weeks in VDZ group were 51.6%, 61.3%, and 66.7%. The remission rates at 8, 24, and 56 weeks in the UST group were 66.7%, 65.0%, and 66.7%, respectively. Both treatments were comparable in inducing and maintaining clinical remission over 54-56 weeks, with no significant differences observed in the Lichtiger clinical activity index. Subgroup analyses highlighted the potential short-term effectiveness of UST among cases of bio-failure and a white blood cell level ≥ 9000/µL. Safety profiles were generally favorable, with no significant adverse events. Usutekinumab demonstrated effectiveness as a salvage therapy in patients who failed VDZ. Despite the increased disease severity in the UST group compared to the VDZ group, both groups demonstrated similar remission rates, suggesting UST shows significant efficacy even in moderate to severe UC.

Deep mucosal healing in ulcerative colitis: how deep is better?

Ulcerative colitis (UC), characterized by its recurrent nature, imposes a significant disease burden and compromises the quality of life. Emerging evidence suggests that achieving clinical remission is not sufficient for long-term remission. In pursuit of a favorable prognosis, mucosal healing (MH) has been defined as the target of therapies in UC. This paradigm shift has given rise to the formulation of diverse endoscopic and histological scoring systems, providing distinct definitions for MH. Endoscopic remission (ER) has been widely employed in clinical practice, but it is susceptible to subjective factors related to endoscopists. And there's growing evidence that histological remission (HR) might be associated with a lower risk of disease flares, but the incorporation of HR as a routine therapeutic endpoint remains a debate. The integration of advanced technology has further enriched the definition of deep MH. Up to now, a universal standardized definition for deep MH in clinical practice is currently lacking. This review will focus on the definition of deep MH, from different dimensions, and analyze strengths and limitations, respectively. Subsequent multiple large-scale trials are needed to validate the concept of deep MH, offering valuable insights into potential benefits for UC patients.

A global consensus on the definitions, diagnosis and management of fibrostenosing small bowel Crohn's disease in clinical practice

Fibrostenosis of the small bowel is common in patients with Crohn's disease. No consensus recommendations on definition, diagnosis and management in clinical practice are currently available. In this Consensus Statement, we present a clinical practice RAND/UCLA appropriateness study on the definition, diagnosis and clinical management of fibrostenosing Crohn's disease. It was conducted by a panel of 28 global experts and one patient representative. Following a systematic literature review, 526 candidate items grouped into 136 questions were generated and subsequently evaluated for appropriateness. Strictures are best defined as wall thickening, luminal narrowing and prestenotic dilation. Cross-sectional imaging is required for accurate diagnosis of fibrostenosing Crohn's disease, and it is recommended before making treatment decisions. It should also assess the degree of inflammation in the bowel wall. Multiple options for medical anti-inflammatory, endoscopic and surgical therapies were suggested, including follow-up strategies following therapy. This Consensus Statement supports clinical practice through providing guidance on definitions, diagnosis and therapeutic management of patients with fibrostenosing small bowel Crohn's disease.

Fecal calprotectin and platelet count predict histologic disease activity in pediatric ulcerative colitis: results from a projection-predictive feature selection

Especially for pediatric patients, proxies of mucosal inflammation are needed. The Pediatric Ulcerative Colitis Activity Index (PUCAI) has been established to predict clinical and endoscopic disease activity. However, histologic inflammation might persist. We applied a special variable selection technique to predict histologic healing in pediatric ulcerative colitis (UC) as parsimoniously (but still as precisely) as possible. The retrospective analysis included data from two study cohorts, comprising 91 visits from 59 pediatric patients with UC. A Bayesian ordinal regression model was used in combination with a projection-predictive feature selection (PPFS) to identify a minimal subset of clinical and laboratory parameters sufficient for the prediction of histologic disease activity. Following the PPFS, CEDATA-GPGE patient registry data were analyzed to investigate the relevance of the selected predictors in relation to PUCAI and Physician Global Assessment (PGA) in up to 6697 patient visits. Fecal calprotectin (FC) and platelet count were identified as the minimal subset of predictors sufficient for prediction of histologic disease activity in pediatric UC. FC and platelet count also appeared to be associated with increasing disease activity as measured by PUCAI and PGA in the CEDATA-GPGE registry. Based on the selected model, predictions can be performed with a Shiny web app.  Conclusion: Our statistical approach constitutes a reproducible and objective tool to select a minimal subset of the most informative parameters to predict histologic inflammation in pediatric UC. A Shiny app shows how physicians may predict the histologic activity in a user-friendly way using FC and platelet count. To generalize the findings, further prospective studies will be needed. What is Known: • Histologic healing is a major endpoint in the therapy of ulcerative colitis (UC). • The PUCAI score has been established to predict disease activity in pediatric UC but is not suitable for the prediction of histologic healing. What is New: • Our Bayesian ordinal regression model in combination with a projection-predictive feature selection is a reproducible and objective tool to select the minimal subset of clinical and laboratory parameters to predict histologic inflammation in pediatric UC. • Histologic inflammation in pediatric UC can be non-invasively predicted based on the combination of fecal calprotectin levels and platelet count.

Artificial intelligence and endo-histo-omics: new dimensions of precision endoscopy and histology in inflammatory bowel disease

Integrating artificial intelligence into inflammatory bowel disease (IBD) has the potential to revolutionise clinical practice and research. Artificial intelligence harnesses advanced algorithms to deliver accurate assessments of IBD endoscopy and histology, offering precise evaluations of disease activity, standardised scoring, and outcome prediction. Furthermore, artificial intelligence offers the potential for a holistic endo-histo-omics approach by interlacing and harmonising endoscopy, histology, and omics data towards precision medicine. The emerging applications of artificial intelligence could pave the way for personalised medicine in IBD, offering patient stratification for the most beneficial therapy with minimal risk. Although artificial intelligence holds promise, challenges remain, including data quality, standardisation, reproducibility, scarcity of randomised controlled trials, clinical implementation, ethical concerns, legal liability, and regulatory issues. The development of standardised guidelines and interdisciplinary collaboration, including policy makers and regulatory agencies, is crucial for addressing these challenges and advancing artificial intelligence in IBD clinical practice and trials.

Histopathology imaging and clinical data including remission status in pediatric inflammatory bowel disease

The incidence of inflammatory bowel disease (IBD) is increasing annually. Children with IBD often suffer significant morbidity due to physical and emotional effects of the disease and treatment. Corticosteroids, often a component of therapy, carry undesirable side effects with long term use. Steroid-free remission has become a standard for care-quality improvement. Anticipating therapeutic outcomes is difficult, with treatments often leveraged in a trial-and-error fashion. Artificial intelligence (AI) has demonstrated success in medical imaging classification tasks. Predicting patients who will attain remission will help inform treatment decisions. The provided dataset comprises 951 tissue section scans (167 whole-slides) obtained from 18 pediatric IBD patients. Patient level structured data include IBD diagnosis, 12- and 52-week steroid use and name, and remission status. Each slide is labelled with biopsy site and normal or abnormal classification per the surgical pathology report. Each tissue section scan from an abnormal slide is further classified by an experienced pathologist. Researchers utilizing this dataset may select from the provided outcomes or add labels and annotations from their own institutions.

Add-on multiple submucosal injections of the RNA oligonucleotide GUT-1 to anti-TNF antibody treatment in patients with moderate-to-severe ulcerative colitis: an open-label, proof-of concept study

BACKGROUND

Carbohydrate sulfotransferase 15 (CHST15) is an enzyme biosynthesizing matrix glycosaminoglycan that modulates tissue remodeling. We evaluated the efficacy of add-on submucosal injections of GUT-1, the RNA oligonucleotide inhibitor of CHST15, to ongoing anti-tumor necrosis factor (TNF) antibody treatment in patients with moderate-to-severe ulcerative colitis (UC).

METHODS

This was an open-label study of 250 nM of GUT-1 by endoscopic submucosal injections at weeks 0, 2, 4 in five UC patients who lost response during maintenance treatment to anti-TNF antibodies. The primary endpoint was the rate of endoscopic improvement at week 6 and secondary endpoints included the rates of clinical remission by modified Mayo Score (mMS). Patients received follow-up observation with continuous maintenance treatment by the same anti-TNF antibody till the time of clinical recurrence or for overall 52 weeks.

RESULTS

At week 6, rates of endoscopic improvement and clinical remission were 80% (n = 4/5) and 60% (n = 3/5), respectively. The mean Endoscopy Subscore was reduced from 2.4 (95%CI: 1.7 to 3.1) at baseline, to 1.0 (95%CI: 0.1 to 1.9) at week 6. The mean mMS was reduced from 7.8 (95%CI: 6.2 to 9.4) to 1.3 (95%CI: 2.9 to 4.3). GUT-1 was well tolerated. Three patients did not show clinical recurrence for 52 weeks. All three corticosteroid-dependent patients showed no corticosteroid exposure for at least 24 weeks after achieving clinical remission. Multiple dosing was also well tolerated.

CONCLUSIONS

Add-on multiple injections of GUT-1 to ongoing anti-TNF antibody was able to induce rapid and durable clinical responses in UC patients who lost response to anti-TNF therapy.

TRIAL REGISTRATION

Clinical trial Registration Number (Japan): UMIN000020900.

Early Versus Late Use of Vedolizumab in Ulcerative Colitis: Clinical, Endoscopic, and Histological Outcomes

BACKGROUND AND AIMS

We explored the potential for differential efficacy of vedolizumab between early and late ulcerative colitis [UC] with evaluation of clinical, endoscopic, and histological endpoints.

METHODS

This was a multicentre, multinational, open-label study in patients with moderately-to-severely active UC, defining early UC by a disease duration <4 years and bio-naïve and late UC by a disease duration > 4 years and additional exposure to tumour necrosis factor antagonists. Patients received standard treatment with intravenous vedolizumab for 52 weeks [300 mg Weeks 0, 2, 6, every 8 weeks thereafter without escalation]. The primary endpoint was corticosteroid-free clinical remission with endoscopic improvement [total Mayo score ≤2 with no subscore >1] at both Weeks 26 and 52.

RESULTS

A total of 121 patients were included: in the "early" group, 25/59 [42.4%] achieved the primary endpoint versus 19/62 [30.6%] in the "late" group [p = 0.18]. There were no significant differences between the two groups in endoscopic improvement [Week 26: "early" 32/59 [54.2%] versus "late" 29/62 [46.8%]; p = 0.412; Week 52: 27/59 [45.8%] versus 25/62 [40.3%]; p = 0.546] or in histological remission [Robarts Histopathology Index <3 without neutrophils in the epithelium and lamina propria] [Week 26: 24/59 [40.7%] versus 21/62 [33.9%]; p = 0.439; Week 52: 22/59 [37.3%] versus 22/62 [35.5%]; p = 0.837].

CONCLUSIONS

No significant differences in clinical, endoscopic, and histological outcomes were observed between "early" and "late" disease.

Differences Between the 2016 and 2022 Food and Drug Administration Guidance-Implications for Design and Interpretation of Clinical Trials in Ulcerative Colitis

Background

In 2022, the Food and Drug Administration (FDA) updated its draft guidance for drug development in ulcerative colitis, replacing the version from 2016. Several changes from the 2016 version merit further discussion as they impact clinical trial design and the interpretation of trial results.

Methods

We compared both documents and critically appraised the changes and implications for future clinical trials.

Results

The 2022 guidance recommends full colonoscopy, rather than flexible sigmoidoscopy, to document disease activity in all involved segments of the colon. The concordance between the findings of the 2 procedures is very high and there is little evidence to support colonoscopy over sigmoidoscopy. The use of colonoscopy, rather than sigmoidoscopy, is also associated with a higher burden to trial participants who must undergo full bowel preparation, cost, and a potential for more adverse events. The definition of the Mayo endoscopic score of 0 was changed from the original publication to "normal appearance of mucosa," which suggests that endoscopic signs of prior disease, such as pseudopolyps and scarring, are incompatible with a score 0, even though they are not associated with active disease. The term "mucosal healing" has been abolished and histologic outcomes defined as exploratory. A welcome change is that shorter washout periods than 5 half-lives will be considered to reduce patient exposure to corticosteroids as bridging therapy.

Conclusions

The 2022 FDA draft guidance includes changes which for the most part are not informed by empirical evidence, which may ultimately complicate interpretation of future trials and preclude comparisons with past trials.

Submucosal Injection of the RNA Oligonucleotide GUT-1 in Active Ulcerative Colitis Patients: A Randomized, Double-Blind, Placebo-Controlled Phase 2a Induction Trial

BACKGROUND AND AIMS

Carbohydrate sulfotransferase 15 [CHST15] biosynthesizes sulphated matrix glycosaminoglycans and is implicated in intestinal inflammation and fibrosis. Here, we evaluate the efficacy and safety of the double-stranded RNA oligonucleotide GUT-1, a specific blocker of CHST15, as induction therapy in patients with ulcerative colitis [UC].

METHODS

In this randomized, double-blind, placebo-controlled, phase 2a study, we enrolled endoscopically active UC patients, refractory to conventional therapy, in five hospital centres across Germany. Patients were randomized 1:1:1 using a block randomized technique to receive a single dosing of 25 nM GUT-1, 250 nM GUT-1, or placebo by endoscopic submucosal injections. The primary outcome measure was improvement of endoscopic lesions at weeks 2 or 4. The secondary outcome measures included clinical and histological responses. Safety was assessed in all patients who received treatment.

RESULTS

Twenty-eight patients were screened, 24 were randomized, and 21 were evaluated. Endoscopic improvement at weeks 2 or 4 was achieved by 71.4% in the GUT-1 250 nM, 0% in the GUT-1 25 nM, and 28.6% in the placebo group. Clinical remission was shown by 57.1% in the GUT-1 250 nM, 0% in the GUT-1 25 nM, and 14.3% in the placebo groups. Histological improvement was shown by 42.9% in the GUT-1 250 nM, 0% in the GUT-1 25 nM, and 0% in the placebo groups. GUT-1 250 nM reduced CHST15 expression significantly and suppressed mucosal inflammation and fibrosis. GUT-1 application was well tolerated.

CONCLUSION

Single dosing by submucosal injection of GUT-1 repressed CHST15 mucosal expression and may represent a novel induction therapy by modulating tissue remodelling in UC.

Astragalus Polysaccharide Alleviates Ulcerative Colitis by Regulating the Balance of mTh17/mTreg Cells through TIGIT/CD155 Signaling

The balance between memory Th17 cells (mTh17) and memory Treg cells (mTreg) plays a key role in the pathogenesis of ulcerative colitis (UC), and TIGIT signaling is involved in the differentiation of mTh17/mTreg cells. Astragalus polysaccharide (APS) has good immunomodulatory and anti-inflammatory effects. Here, the regulatory effects and potential mechanisms of APS on mTh17/mTreg cells in UC are explored. A UC model was induced with dextran sulfate sodium (DSS) and treated simultaneously with APS (200 mg/kg/day) for 10 days. After APS treatment, the mice showed a significant increase in colonic length and a significant decrease in colonic weight, colonic weight index and colonic weight/colonic length, and more intact mucosa and lighter inflammatory cell infiltration. Notably, APS significantly down-regulated the percentages of Th17 (CD4+CCR6+), cmTh17 (CD4+CCR7+CCR6+) and emTh17 (CD4+CCR7-CCR6+) cells and significantly up-regulated the percentages of cmTreg (CD4+CCR7+Foxp3+) and emTreg (CD4+CCR7-Foxp3+) cells in the mesenteric lymph nodes of the colitis mice. Importantly, APS reversed the expression changes in the TIGIT molecule on mTh17/mTreg cells in the colitis mice with fewer CD4+CCR6+TIGIT+, CD4+CCR7-CCR6+TIGIT+ and CD4+CCR7-CCR6+TIGIT+ cells and more CD4+Foxp3+TIGIT+, CD4+CCR7-Foxp3+TIGIT+ and CD4+CCR7-Foxp3+TIGIT+ cells. Meanwhile, APS significantly inhibited the protein expression of the TIGIT ligands CD155, CD113 and CD112 and downstream proteins PI3K and AKT in the colon tissues of the colitis mice. In conclusion, APS effectively alleviated DSS-induced UC in mice by regulating the balance between mTh17/mTreg cells, which was mainly achieved through regulation of the TIGIT/CD155 signaling pathway.

Assessing the economics of biologic and small molecule therapies for the treatment of moderate to severe ulcerative colitis in Japan: a cost per responder analysis of upadacitinib

AIM

Patients with moderately to severely active ulcerative colitis have an increasing number of advanced therapy options including several biologics and Janus kinase inhibitors. Though data on efficacy and safety of these advanced therapies are available, less is known about the potential economic implications of their utilization in Japan. We evaluated the relative value of these advanced therapies in Japan using a locally developed cost per responder model.

METHODS

A model was developed using relevant clinical endpoints and treatment costs to calculate cost per responder of all advanced therapies used for moderately to severely active ulcerative colitis treatment in Japan. Cost per responder was assessed in biologic-naïve and biologic-exposed populations, respectively. The model incorporated induction and maintenance therapy pathways as patients progressed through based on efficacy rates (clinical response, clinical remission and endoscopic improvement). Total costs for induction and maintenance included: drug acquisition, drug administration and serious adverse event management (as necessary) for responders, with additional rescue treatment cost only for non-responders.

RESULTS

Upadacitinib showed lower cost per clinical response and cost per clinical remission across both biologic-naïve and biologic-exposed populations with only one exemption in cost per clinical remission in biologic-naïve population. In addition, upadacitinib demonstrated lower cost per endoscopic improvement in both populations. Janus kinase inhibitors outperformed with lower cost per responder than other mediations across all outcomes and patient populations with the exception of tofacitinib for clinical remission in biologic-exposed UC population.

LIMITATIONS

Comparative data used in this analysis have been derived from network meta-analysis, not from direct comparison.

CONCLUSIONS

The results of this cost per responder analysis suggest upadacitinib is a cost-effective option for the first- and second-line treatment of moderately to severely active ulcerative colitis in Japan.

Standardizing Randomized Controlled Trials in Celiac Disease: An International Multidisciplinary Appropriateness Study

BACKGROUND & AIMS

There is a need to develop safe and effective pharmacologic options for the treatment of celiac disease (CeD); however, consensus on the appropriate design and configuration of randomized controlled trials (RCTs) in this population is lacking.

METHODS

A 2-round modified Research and Development/University of California Los Angeles Appropriateness Method study was conducted. Eighteen gastroenterologists (adult and pediatric) and gastrointestinal pathologists voted on statements pertaining to the configuration of CeD RCTs, inclusion and exclusion criteria, gluten challenge, and trial outcomes. Two RCT designs were considered, representing the following distinct clinical scenarios for which pharmacotherapy may be used: trials incorporating a gluten challenge to simulate exposure; and trials evaluating reversal of histologic changes, despite attempted adherence to a gluten-free diet. Each statement was rated as appropriate, uncertain, or inappropriate, using a 9-point Likert scale.

RESULTS

For trials evaluating prevention of relapse after gluten challenge, participants adherent to a gluten-free diet for 12 months or more with normal or near-normal-sized villi should be enrolled. Gluten challenge should be FODMAPS (fermentable oligosaccharides, disaccharides, monosaccharides, and polyols) free, and efficacy evaluated using histology with a secondary patient-reported outcome measure. For trials evaluating reversal of villus atrophy, the panel voted it appropriate to enroll participants with a baseline villus height to crypt depth ratio ≤2 and measure efficacy using a primary histologic end point. Guidance for measuring histologic, endoscopic, and patient-reported outcomes in adult and pediatric patients with CeD are provided, along with recommendations regarding the merits and limitations of different end points.

CONCLUSIONS

We developed standardized recommendations for clinical trial design, eligibility criteria, outcome measures, gluten challenge, and disease evaluations for RCTs in patients with CeD.

Histologic assessments in ulcerative colitis: the evidence behind a new endpoint in clinical trials

INTRODUCTION

Treatment goals for ulcerative colitis (UC) are evolving from the achievement of clinical remission to more rigorous goals defined by endoscopic and histologic healing. Achievement of deeper remission targets aims to reduce the risk of colectomy, hospitalizations, and colorectal cancer.

AREAS COVERED

This review covers histologic assessments, histologic remission as a clinical trial endpoint, and the association between histologic disease activity and clinical outcomes. Future directions are also discussed, including the use of advanced imaging and artificial intelligence technologies, as well as potential future treatment targets beyond histologic remission.

EXPERT OPINION

Histologic assessments are used for their sensitivity in measuring mucosal inflammatory changes in UC. Due to correlation with disease activity, histologic assessments may support clinical decision-making regarding treatment decisions as such assessments can be associated with rates of clinical relapse, hospitalization, colectomy, and neoplasia. While histologic remission is limited by varying definitions and multiple histologic indices, work is ongoing to create a consensus on the use of histologic assessments in clinical trials. As research advances, aspirational targets beyond histologic remission, such as molecular healing and disease clearance, are being explored.

Neutrophil-only Histological Assessment of Ulcerative Colitis Correlates with Endoscopic Activity and Predicts Long-term Outcomes in a Multicentre Study

BACKGROUNDS AND AIMS

Absence of neutrophils is the minimum standard to consider histological remission of ulcerative colitis [UC]. The PICaSSO Histological Remission Index [PHRI] is a new simple index for UC, based only on the detection of neutrophils. We evaluate PHRI's correlation with endoscopy and its prognostic value compared with other established indices.

METHODS

Consecutive patients with UC underwent colonoscopy at two referral centres [Birmingham, UK, and Milan, Italy,] and were followed up for 2 years. Correlation between histology (PHRI, Nancy [NHI], and Robarts [RHI] indexes) and endoscopy (Mayo Endoscopic Score [MES], Ulcerative Colitis Endoscopic Index of Severity [UCEIS], and PICaSSO index) was calculated as Spearman coefficients. Diagnostic performance of endoscopy was assessed with receiver operating characteristic [ROC] curves and outcome stratification with Kaplan-Meier curves.

RESULTS

A total of 192 patients with UC was enrolled, representing all grades of endoscopic severity. Correlation between histology and endoscopy did not differ significantly when using PHRI instead of NHI or RHI. In particular, PHRI's correlation with MES, UCEIS, and PICaSSO was 0.745, 0.718, and 0.694, respectively. Endoscopically-assessed remission reflected the absence of neutrophils [PHRI = 0] with areas under the ROC curve of 0.905, 0.906, and 0.877 for MES, UCEIS, and PICaSSO, respectively. The hazard ratio for disease flare between patients in histological activity/remission was statistically similar [p >0.05] across indexes [2.752, 2.706, and 2.871 for RHI, NHI, and PHRI, respectively].

CONCLUSION

PHRI correlates with endoscopy and stratifies risk of relapse similarly to RHI and NHI. Neutrophil-only assessment of UC is a simple yet viable alternative to established histological scores.

Lack of Benefit for Early Escalation to Advanced Therapies in Ulcerative Colitis: Critical Appraisal of Current Evidence

Although ulcerative colitis [UC] shares many common pathways and therapeutic options with Crohn's disease [CD], CD patients are four times more likely to undergo surgery 10 years into their disease in the biological era and are more likely to have extraintestinal manifestations than UC patients. Early treatment in CD has been demonstrated to modify the natural history of the disease and potentially delay surgery. Previous reviews on this topic have borrowed their evidence from CD to make UC-specific recommendations. This review highlights the emergence of UC-specific data from larger cohort studies and a comprehensive individual patient data systemic review and meta-analysis to critically appraise evidence on the utility of early escalation to advanced therapies with respect to short-, medium-, and long-term outcomes. In UC, the utility of the early escalation concept for the purposes of changing the natural history, including reducing colectomy and hospitalizations, is not supported by the available data. Data on targeting clinical, biochemical, endoscopic, and histological outcomes are needed to demonstrate that they are meaningful with regard to achieving reductions in hospitalization and surgery, improving quality of life, and minimizing disability. Analyses of different populations of UC patients, such as those with 'relapsing & remitting' disease or with severe or complicated disease course, are urgently needed. The costs and risk/benefit profile of some of the newer advanced therapies should be carefully considered. In this clinical landscape, it appears premature to advocate an indiscriminate 'one size fits all' approach to escalating to advanced therapies early during the course of UC.

Evaluation of Disease Activity in Inflammatory Bowel Disease: Diagnostic Tools in the Assessment of Histological Healing

Inflammatory bowel disease (IBD) comprises two types of chronic intestinal disorders: Crohn's disease and ulcerative colitis. In long-standing ulcerative colitis disease activity, histological persistent inflammation has been linked to an increased risk of relapse, and long-term corticosteroid use, even when endoscopic remission is reached. In Crohn's disease, the discontinuous nature of lesions and transmural inflammation have limited the standardized histological assessment. The current evidence from research proposes that besides clinical and endoscopic healing, the achievement of histological healing constitutes an endpoint to assess disease activity and remission in IBD patients concerning better long-term disease outcomes. Histological alterations may persist even in the absence of endoscopic lesions. For these reasons, new advanced techniques promise to revolutionize the field of IBD by improving the endoscopic and histologic assessment, disease characterization, and ultimately patient care, with an established role in daily practice for objective assessment of lesions. This review outlines the importance of including microscopic evaluation in IBD, highlighting the clinical benefits of a deep state of disease remission using validated diagnostic methods and scoring systems for daily clinical practice.

Density of Biopsy Sampling Required to Ensure Accurate Histological Assessment of Inflammation in Active Ulcerative Colitis

BACKGROUND

Histological response to treatment is an important outcome in patients with ulcerative colitis (UC). The accuracy of biopsy-based measurements of inflammation may be limited by error imposed by natural microscopic heterogeneity on the scale of individual biopsies. We determined the magnitude of this error, its histological correlates, and the density of biopsy sampling within mucosal regions of interest required to meet specified benchmarks for accuracy.

METHODS

A total of 994 sequential 1-mm digital microscopic images (virtual biopsies) from consecutive colectomies from patients with clinically severe UC were scored by 2 pathologists. Agreement statistics for Geboes subscores and Nancy (NHI) and Robarts Histological Indices (RHI) between random samples from 1 to 10 biopsies and a reference mean score across a 2-cm region of mucosa were calculated using bootstrapping with 2500 iterations.

RESULTS

The agreement statistics improved across all indices as the biopsy density increased, with the largest proportional gains occurring with addition of the second and third biopsies. One biopsy achieved moderate to good agreement with 95% confidence for NHI and RHI corresponding to scale-specific errors of 0.40 (0.25-0.66) and 3.02 (2.08-5.36), respectively; and 3 biopsies achieved good agreement with 95% confidence corresponding to scale-specific errors of 0.22 (0.14-0.39) and 1.87 (1.19-3.25), respectively. Of the individual histological features, erosions and ulcers had the greatest impact on the agreement statistics.

CONCLUSIONS

In the setting of active colitis, up to 3 biopsy samples per region of interest may be required to overcome microscopic heterogeneity and ensure accurate histological grading.

Histologic Predictors of Clinical Outcomes and Healthcare Utilization in Patients With Ileal Pouch-Anal Anastomosis

BACKGROUND

The prognostic significance of histology in ileal pouch-anal anastomosis (IPAA) remains unclear. The aim of this study was to evaluate if histologic variables are predictive of IPAA clinical outcomes and healthcare utilization.

METHODS

This was a retrospective cohort study of patients with IPAA undergoing surveillance pouchoscopy at a tertiary care institution. Pouch body biopsies were reviewed by gastrointestinal pathologists, who were blinded to clinical outcomes, for histologic features of acute or chronic inflammation. Charts were reviewed for clinical outcomes including development of acute pouchitis, chronic pouchitis, biologic or small molecule initiation, hospitalizations, and surgery. Predictors of outcomes were analyzed using univariable and multivariable logistic and Cox regression.

RESULTS

A total of 167 patients undergoing surveillance pouchoscopy were included. Polymorphonuclear leukocytes (odds ratio [OR], 1.67), ulceration and erosion (OR, 2.44), chronic inflammation (OR, 1.97), and crypt distortion (OR, 1.89) were associated with future biologic or small molecule initiation for chronic pouchitis. Loss of goblet cells was associated with development of chronic pouchitis (OR, 4.65). Pyloric gland metaplasia was associated with hospitalizations (OR, 5.24). No histologic variables were predictive of development of acute pouchitis or surgery. In an exploratory subgroup analysis of new IPAA (<1 year), loss of goblet cells was associated with acute pouchitis (OR, 14.86) and chronic pouchitis (OR, 12.56). Pyloric gland metaplasia was again associated with hospitalizations (OR, 13.99).

CONCLUSIONS

Histologic findings may be predictive of IPAA outcomes. Pathologists should incorporate key histologic variables into pouchoscopy pathology reports. Clinicians may need to more closely monitor IPAA patients with significant histologic findings.

Higher Adalimumab Trough Levels Are Associated with Histologic Remission and Mucosal Healing in Inflammatory Bowel Disease

(1) Many patients with inflammatory bowel disease (IBD) in endoscopic remission have persistent histologic activity, which is associated with worse outcomes. There are limited data on the association between adalimumab drug concentrations and histologic outcomes using validated histologic indices. We aimed to assess the relationship between adalimumab concentrations and the Robarts Histopathology Index (RHI). (2) Patients from a tertiary IBD center from 2013 to 2020 with serum adalimumab (ADA) trough concentrations measured during maintenance therapy (≥14 weeks) and a colonoscopy or flexible sigmoidoscopy with biopsies performed within 90 days of drug level were included. Blinded histologic scoring using the RHI was performed. Primary analysis assessed the relationship between adalimumab drug concentrations and histologic remission using receiver operating characteristic curve analysis. (3) In 36 patients (26 Crohn's Disease, 9 ulcerative colitis, 1 indeterminate), median adalimumab concentrations were higher (17.3 ug/mL, 12.2-24.0) in patients with histologic remission compared to those without (10.3 ug/mL, 6.8-13.9, p = 0.008). The optimal ADA concentration identified using the Youden threshold was ≥16.3 ug/mL (sensitivity 70%, specificity 90%). Patients with ADA ≥ 16.3 ug/mL had higher histologic remission rates (78%) compared to lower ADA concentrations (14%, p= 0.002), as well as higher mucosal healing rates (86%) compared to lower levels (12%, p = 0.001). Symptoms correlated weakly and non-significantly with both histologic (RHI) scores (r = 0.25, p = 0.2) and adalimumab concentrations (r = 0.05, p = 0.8). (4) The current study demonstrated that higher serum adalimumab concentrations (≥16.3 ug/mL) are needed for histologic remission and mucosal healing assessed using the RHI.

Resolving Histological Inflammation in Ulcerative Colitis With Mirikizumab in the LUCENT Induction and Maintenance Trial Programmes

BACKGROUND AND AIMS

To evaluate the effect of mirikizumab, a p19-targeted anti-interleukin-23, on histological and/or endoscopic outcomes in moderately-to-severely active ulcerative colitis [UC].

METHODS

Endoscopic remission [ER], histological improvement [HI], histological remission [HR], histological-endoscopic mucosal improvement [HEMI], and histological-endoscopic mucosal remission [HEMR] were assessed at Week [W]12 [LUCENT-1: N = 1162, induction] and W40 [LUCENT-2: N = 544, maintenance] for patients randomised to mirikizumab or placebo. Analyses were performed to evaluate predictors of: HEMI at W12 with mirikizumab and HEMR at W40 in patients re-randomised to subcutaneous [SC] mirikizumab; associations between W12 histological/endoscopic endpoints and W40 outcomes in mirikizumab responders re-randomised to mirikizumab SC; and associations between W40 endoscopic normalisation [EN] with/without HR.

RESULTS

Significantly more patients treated with mirikizumab achieved HI, HR, ER, HEMI, and HEMR vs placebo [p <0.001], irrespective of prior biologic/tofacitinib failure [p <0.05]. Lower clinical baseline disease activity, female sex, no baseline immunomodulator use, and no prior biologic/tofacitinib failure were predictors of HEMI at W12 [p <0.05]. Corticosteroid use and longer disease duration were negative predictors of achieving HEMR at W40 [p <0.05]. W12 HI, HR, or ER was associated with W40 HEMI or HEMR [p <0.05]; ER at W12 was associated with clinical remission [CR] [p <0.05] and corticosteroid-free remission [CSFR] at W40 [p = 0.052]. HR and HEMR at W12 were associated with CSFR, CR, and symptomatic remission at W40. Alternate HEMR [EN + HR] at W40 was associated with bowel urgency remission at W40 [p <0.05].

CONCLUSIONS

Early resolution of endoscopic and histological inflammation with mirikizumab is associated with better UC outcomes. Clinicaltrials.gov: LUCENT-1, NCT03518086; LUCENT-2, NCT03524092.

Mirikizumab for the treatment of moderate to severe ulcerative colitis

Despite a growing number of available therapeutic options for ulcerative colitis (UC), up to 50% of patients do not respond to initial treatment or lose response over time, highlighting the need for novel therapies. The IL-23 pathway has emerged as an important therapeutic target for UC. Mirikizumab is a humanized IgG4 monoclonal antibody against the p19 subunit of IL-23, dosed intravenously during induction and subcutaneously during maintenance. It is effective for the induction and maintenance of remission in moderately to severely active UC, including patients with prior failure of biological or tofacitinib therapy. Like other IL-23 antagonists, mirikizumab has a favorable safety profile. It is the first agent of its class to receive regulatory approval for moderately to severely active UC in Europe.

Accelerating pharmaceutical R&D with a user-friendly AI system for histopathology image analysis

A system for analysis of histopathology data within a pharmaceutical R&D environment has been developed with the intention of enabling interdisciplinary collaboration. State-of-the-art AI tools have been deployed as easy-to-use self-service modules within an open-source whole slide image viewing platform, so that non-data scientist users (e.g., clinicians) can utilize and evaluate pre-trained algorithms and retrieve quantitative results. The outputs of analysis are automatically cataloged in the database to track data provenance and can be viewed interactively on the slide as annotations or heatmaps. Commonly used models for analysis of whole slide images including segmentation, extraction of hand-engineered features for segmented regions, and slide-level classification using multi-instance learning are included and new models can be added as needed. The source code that supports running inference with these models internally is backed up by a robust CI/CD pipeline to ensure model versioning, robust testing, and seamless deployment of the latest models. Examples of the use of this system in a pharmaceutical development workflow include glomeruli segmentation, enumeration of podocyte count from WT-1 immuno-histochemistry, measurement of beta-1 integrin target engagement from immunofluorescence, digital glomerular phenotyping from periodic acid-Schiff histology, PD-L1 score prediction using multi-instance learning, and the deployment of the open-source Segment Anything model to speed up annotation.

The Number of Colon Crypts in Digital Mucosal Samples: A New Independent Parameter for Diagnosing Ulcerative Colitis

Background/Aim

It has been demonstrated that most routine biopsies from the colon and rectum display cross-cut crypts (CCC). The aim was to assess the number of CCC in microscopic isometric digital samples (0.500 mm2) from routine colon biopsies.

Patients and Methods

Colon biopsies from 224 patients were investigated: 99 in patients with ulcerative colitis (UC), 31 UC in remission (UCR), 28 infectious colitis (IC), 7 resolved IC (RIC), 19 diverticular sigmoiditis (DS), and 40 normal colon mucosa (NCM).

Results

A total of 8,024 CCC were registered: 2,860 (35.6%) in UC, 1,319 UCR (16.4%), 849 (10.6%) in IC, 340 (4.2%) in RIC, 795 (9.9%) in DS, and 1,861 (23.2%) in NCM. The CCC frequencies in UC and IC were significantly lower (p<0.05) than those in UCR, RIC, DS, and NCM.

Conclusion

By the simple algorithm of counting CCC in standardized isometric microscopic digital circles measuring 0.500 mm2, it was possible to differentiate between UC (long-lasting inflammation) and IC (short-lasting inflammation) on the one hand, and UCR, RIC, DS (persistent inflammation), and NCM, on the other. The counting of CCC in the algorithm by five pathologists working in three disparate European Countries, was found to be reproducible.

Dose escalation randomised study of efmarodocokin alfa in healthy volunteers and patients with ulcerative colitis

BACKGROUND

The interleukin-22 cytokine (IL-22) has demonstrated efficacy in preclinical colitis models with non-immunosuppressive mechanism of action. Efmarodocokin alfa (UTTR1147A) is a fusion protein agonist that links IL-22 to the crystallisable fragment (Fc) of human IgG4 for improved pharmacokinetic characteristics, but with a mutation to minimise Fc effector functions.

METHODS

This randomised, phase 1b study evaluated the safety, tolerability, pharmacokinetics and pharmacodynamics of repeat intravenous dosing of efmarodocokin alfa in healthy volunteers (HVs; n=32) and patients with ulcerative colitis (n=24) at 30-90 µg/kg doses given once every 2 weeks or monthly (every 4 weeks) for 12 weeks (6:2 active:placebo per cohort).

RESULTS

The most common adverse events (AEs) were on-target, reversible, dermatological effects (dry skin, erythema and pruritus). Dose-limiting non-serious dermatological AEs (severe dry skin, erythema, exfoliation and discomfort) were seen at 90 μg/kg once every 2 weeks (HVs, n=2; patients, n=1). Pharmacokinetics were generally dose-proportional across the dose levels, but patients demonstrated lower drug exposures relative to HVs at the same dose. IL-22 serum biomarkers and IL-22-responsive genes in colon biopsies were induced with active treatment, and microbiota composition changed consistent with a reversal in baseline dysbiosis. As a phase 1b study, efficacy endpoints were exploratory only. Clinical response was observed in 7/18 active-treated and 1/6 placebo-treated patients; clinical remission was observed in 5/18 active-treated and 0/6 placebo-treated patients.

CONCLUSION

Efmarodocokin alfa had an adequate safety and pharmacokinetic profile in HVs and patients. Biomarker data confirmed IL-22R pathway activation in the colonic epithelium. Results support further investigation of this non-immunosuppressive potential inflammatory bowel disease therapeutic.

TRIAL REGISTRATION NUMBER

NCT02749630.

Real-World Endoscopic and Histologic Outcomes in Ulcerative Colitis Patients: A Retrospective Cohort Study

BACKGROUND

Histologic activity has emerged as an aspirational therapeutic goal in ulcerative colitis management. It is not yet a formal treatment target in ulcerative colitis. However, it could be used as an adjunct to mucosal healing to represent a deeper level of healing. We investigated mucosal and histologic remission rates and potential predictors of these outcomes in a cohort of UC patients.

METHODS

We conducted a retrospective analysis of data collected from UC patients enrolled in an ongoing prospective cohort study. Mucosal healing was defined as Mayo endoscopic score = 0.

RESULTS

A total of 131 patients with ulcerative colitis were enrolled in our study and were prospectively followed for a median length of 2 years (range 0-5 years), totaling 266 study visits. Mucosal healing was recorded for 27 patients at 70 (26%) different study visits. For patients with mucosal healing, histologic remission was achieved in 18/27 (66%) patients. On univariate analysis, sustained clinical remission, SIBDQ scores ≥ 5.5, CRP ≤ 5 mg/dL and absence of corticotherapy were associated with mucosal healing and SIBDQ scores ≥ 5.5 and CRP ≤ 5 mg/dL with histologic healing, respectively. After logistic regression analysis, none of the investigated factors were associated with mucosal and histologic healing. The number of CD8+ intraepithelial lymphocytes (IELs) was significantly greater than the number of CD4+ IELs in periods of disease activity, as well as during mucosal healing (p < 0.01 in both cases).

CONCLUSIONS

Mucosal healing and histologic remission rates are low in real-life settings. The results of univariate analysis indicate that a good quality of life (SIBDQ score) and normal inflammatory markers (CRP) are associated with mucosal and histologic healing. However, frequently used patient- and disease-related factors, including mucosal healing, are not reliable predictors for histologic remission. Greater CD8+ lymphocyte involvement and higher CD8+/CD4+ distribution can have a meaningful impact on understanding the pathogenesis and natural history of ulcerative colitis, as well as future treatment options for lymphocyte-targeting medications.

Artificial Intelligence Enables Quantitative Assessment of Ulcerative Colitis Histology

Ulcerative colitis is a chronic inflammatory bowel disease that is characterized by a relapsing and remitting course. Assessment of disease activity critically informs treatment decisions. In addition to endoscopic remission, histologic remission is emerging as a treatment target and a key factor in the evaluation of disease activity and therapeutic efficacy. However, manual pathologist evaluation is semiquantitative and limited in granularity. Machine learning approaches are increasingly being developed to aid pathologists in accurate and reproducible scoring of histology, enabling precise quantitation of clinically relevant features. Here, we report the development and validation of convolutional neural network models that quantify histologic features pertinent to ulcerative colitis disease activity, directly from hematoxylin and eosin-stained whole slide images. Tissue and cell model predictions were used to generate quantitative human-interpretable features to fully characterize the histology samples. Tissue and cell predictions showed comparable agreement to pathologist annotations, and the extracted slide-level human-interpretable features demonstrated strong correlations with disease severity and pathologist-assigned Nancy histological index scores. Moreover, using a random forest classifier based on 13 human-interpretable features derived from the tissue and cell models, we were able to accurately predict Nancy histological index scores, with a weighted kappa (κ = 0.91) and Spearman correlation (⍴ = 0.89, P < .001) when compared with pathologist consensus Nancy histological index scores. We were also able to predict histologic remission, based on the absence of neutrophil extravasation, with a high accuracy of 0.97. This work demonstrates the potential of computer vision to enable a standardized and robust assessment of ulcerative colitis histopathology for translational research and improved evaluation of disease activity and prognosis.

Correlation Between the Nancy Histopathology Index and Markers of Disease Activity in Pediatric Ulcerative Colitis

The Nancy Histological Index (NHI) was developed to assess histological disease activity in adult ulcerative colitis (UC) patients. However, data in pediatrics is limited. Our aim was to determine whether the NHI correlates with different indices of disease activity in pediatric UC patients. We retrospectively reviewed the NHI in rectal biopsies from 61 pediatric UC patients (median age 14.3 years), of whom 34 (55.7%) were newly diagnosed. The median Pediatric Ulcerative Colitis Activity Index (PUCAI) score among participants was 30 (interquartile range 5-55). Most patients exhibited an NHI of 3 (41/61, 67.2%) or 4 (8/61, 13.1%), reflecting moderate-severe histologic inflammation. A moderate positive correlation was identified between the NHI and PUCAI, fecal calprotectin, and Mayo endoscopic scores ( r = 0.60, 0.54, and 0.56 respectively, P ≤ 0.001), but not with CRP or albumin. These results indicate that the NHI has a modest correlation with clinical, laboratory and endoscopic indices of disease activity in pediatric UC patients.

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.

AI-based histologic scoring enables automated and reproducible assessment of enrollment criteria and endpoints in NASH clinical trials

Clinical trials in nonalcoholic steatohepatitis (NASH) require histologic scoring for assessment of inclusion criteria and endpoints. However, guidelines for scoring key features have led to variability in interpretation, impacting clinical trial outcomes. We developed an artificial intelligence (AI)-based measurement (AIM) tool for scoring NASH histology (AIM-NASH). AIM-NASH predictions for NASH Clinical Research Network (CRN) grades of necroinflammation and stages of fibrosis aligned with expert consensus scores and were reproducible. Continuous scores produced by AIM-NASH for key histological features of NASH correlated with mean pathologist scores and with noninvasive biomarkers and strongly predicted patient outcomes. In a retrospective analysis of the ATLAS trial, previously unmet pathological endpoints were met when scored by the AIM-NASH algorithm alone. Overall, these results suggest that AIM-NASH may assist pathologists in histologic review of NASH clinical trials, reducing inter-rater variability on trial outcomes and offering a more sensitive and reproducible measure of patient therapeutic response.