A Simplified Definition of Histologic Improvement in Ulcerative Colitis and its Association With Disease Outcomes up to 30 Weeks from Initiation of Therapy: Post Hoc Analysis of Three Clinical Trials

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.

Deep Learning Models Capture Histological Disease Activity in Crohn's Disease and Ulcerative Colitis with High Fidelity

BACKGROUND AND AIMS

Histological disease activity in inflammatory bowel disease [IBD] is associated with clinical outcomes and is an important endpoint in drug development. We developed deep learning models for automating histological assessments in IBD.

METHODS

Histology images of intestinal mucosa from phase 2 and phase 3 clinical trials in Crohn's disease [CD] and ulcerative colitis [UC] were used to train artificial intelligence [AI] models to predict the Global Histology Activity Score [GHAS] for CD and Geboes histopathology score for UC. Three AI methods were compared. AI models were evaluated on held-back testing sets, and model predictions were compared against an expert central reader and five independent pathologists.

RESULTS

The model based on multiple instance learning and the attention mechanism [SA-AbMILP] demonstrated the best performance among competing models. AI-modelled GHAS and Geboes subgrades matched central readings with moderate to substantial agreement, with accuracies ranging from 65% to 89%. Furthermore, the model was able to distinguish the presence and absence of pathology across four selected histological features, with accuracies for colon in both CD and UC ranging from 87% to 94% and for CD ileum ranging from 76% to 83%. For both CD and UC and across anatomical compartments [ileum and colon] in CD, comparable accuracies against central readings were found between the model-assigned scores and scores by an independent set of pathologists.

CONCLUSIONS

Deep learning models based upon GHAS and Geboes scoring systems were effective at distinguishing between the presence and absence of IBD microscopic disease activity.

Histological Disease Activity as Predictor of Clinical Relapse, Hospitalization, and Surgery in Inflammatory Bowel Disease: Systematic Review and Meta-Analysis

BACKGROUND

The clinical impact of histological remission on short- and long-term clinical outcomes in patients with inflammatory bowel disease (IBD) is not well established. We assessed risk of clinical relapse, hospitalization, and need for surgery in patients achieving histological remission in comparison with active histological disease.

METHODS

A systematic review was conducted using MEDLINE, Scopus, Cochrane CENTRAL, EMBASE, and conference abstracts from inception to November 2022. Our main outcome was the rate of clinical relapse in patients with IBD who reached histological remission vs patients with active histological disease. Secondary outcomes were clinical complications of IBD such as hospitalization and need for surgery. The endpoints were investigated at 2 time points, 6 to 12 months (short term) and >12 months (long term).

RESULTS

Short-term outcome analysis showed that the risk of clinical relapse was significantly higher in ulcerative colitis patients with active histological disease in comparison with patients at histological remission (risk ratio [RR], 2.41; 95% confidence interval [CI], 1.69-3.44; P < .01). The risk of hospitalization in ulcerative colitis patients was not significant among the 2 groups (RR, 4.22; 95% CI, 0.91-19.62; P = .07). Long-term outcome analysis demonstrated that the risk of clinical relapse (RR, 2.07; 95% CI, 1.55-2.76; P < .01), need for surgery (RR, 3.14; 95% CI, 1.53-6.45; P < .01), and hospitalization (RR, 2.52; 95% CI, 1.59-4.00; P < .01) was significantly higher in patients with active histological disease.

CONCLUSIONS

Histological remission in IBD represents an important therapeutic goal that is not yet routinely pursued in clinical practice. In our study, patients who achieved histological remission have more favorable outcomes than those with active histological disease in ulcerative colitis.

Different levels of healing in inflammatory bowel diseases: mucosal, histological, transmural, barrier and complete healing

Mucosal healing on endoscopy has emerged as a key prognostic parameter in the management of patients with IBD (Crohn's disease, ulcerative colitis/UC) and can predict sustained clinical remission and resection-free survival. The structural basis for this type of mucosal healing is a progressive resolution of intestinal inflammation with associated healing of ulcers and improved epithelial barrier function. However, in some cases with mucosal healing on endoscopy, evidence of histological activity in mucosal biopsies has been observed. Subsequently, in UC, a second, deeper type of mucosal healing, denoted histological healing, was defined which requires the absence of active inflammation in mucosal biopsies. Both levels of mucosal healing should be considered as initial events in the resolution of gut inflammation in IBD rather than as indicators of complete transmural healing. In this review, the effects of anti-inflammatory, biological or immunosuppressive agents as well as small molecules on mucosal healing in clinical studies are highlighted. In addition, we focus on the implications of mucosal healing for clinical management of patients with IBD. Moreover, emerging techniques for the analysis of mucosal healing as well as potentially deeper levels of mucosal healing such as transmural healing and functional barrier healing of the mucosa are discussed. Although none of these new levels of healing indicate a definitive cure of the diseases, they make an important contribution to the assessment of patients' prognosis. The ultimate level of healing in IBD would be a resolution of all aspects of intestinal and extraintestinal inflammation (complete healing).

IL-23 Monoclonal Antibodies for IBD: So Many, So Different?

Interleukin [IL]-23 is a member of the IL-12 family of cytokines and has been implicated in multiple inflammatory disorders including psoriasis, psoriatic arthritis, and the inflammatory bowel diseases [IBDs]. Blockade of both IL-12 and IL-23 using an antibody that targets a shared subunit is highly effective in treating psoriasis, and recent data suggest similar efficacy in IBD with minimal adverse events. In this review, we summarise published data on the efficacy of anti-IL-12/23 therapies in IBD as well as emerging data on more selective anti-IL-23 specific therapies. Last, we discuss novel therapeutics under development which target the IL-23 pathway in unique ways and suggest that a biomarker-driven approach will soon guide clinicians to prescribe anti-IL-23 therapies to the patients most likely to respond to them.

PICaSSO Histologic Remission Index (PHRI) in ulcerative colitis: development of a novel simplified histological score for monitoring mucosal healing and predicting clinical outcomes and its applicability in an artificial intelligence system

Histological remission is evolving as an important treatment target in UC. We aimed to develop a simple histological index, aligned to endoscopy, correlated with clinical outcomes, and suited to apply to an artificial intelligence (AI) system to evaluate inflammatory activity.

METHODS

Using a set of 614 biopsies from 307 patients with UC enrolled into a prospective multicentre study, we developed the Paddington International virtual ChromoendoScopy ScOre (PICaSSO) Histologic Remission Index (PHRI). Agreement with multiple other histological indices and validation for inter-reader reproducibility were assessed. Finally, to implement PHRI into a computer-aided diagnosis system, we trained and tested a novel deep learning strategy based on a CNN architecture to detect neutrophils, calculate PHRI and identify active from quiescent UC using a subset of 138 biopsies.

RESULTS

PHRI is strongly correlated with endoscopic scores (Mayo Endoscopic Score and UC Endoscopic Index of Severity and PICaSSO) and with clinical outcomes (hospitalisation, colectomy and initiation or changes in medical therapy due to UC flare-up). A PHRI score of 1 could accurately stratify patients' risk of adverse outcomes (hospitalisation, colectomy and treatment optimisation due to flare-up) within 12 months. Our inter-reader agreement was high (intraclass correlation 0.84). Our preliminary AI algorithm differentiated active from quiescent UC with 78% sensitivity, 91.7% specificity and 86% accuracy.

CONCLUSIONS

PHRI is a simple histological index in UC, and it exhibits the highest correlation with endoscopic activity and clinical outcomes. A PHRI-based AI system was accurate in predicting histological remission.

Relationship Between Combined Histologic and Endoscopic Endpoints and Efficacy of Ustekinumab Treatment in Patients With Ulcerative Colitis

BACKGROUND & AIMS

Ustekinumab induces and maintains histologic improvement in patients with ulcerative colitis (UC). The clinical relevance of this endpoint alone, and in combination with endoscopic improvement, is unknown.

METHODS

Histologic disease activity was evaluated in 2630 colonic biopsy samples from patients with UC treated in the UNIFI phase 3 UC clinical studies of ustekinumab. We evaluated associations between histologic improvement (defined as the composite of neutrophil infiltration in less than 5% of crypts and no crypt destruction, erosions, ulcerations, or granulation tissue) and clinical endpoints at the end of induction (week 8 and 16) and maintenance (week 44) periods. We assessed the validity of a combined histologic and endoscopic (Mayo endoscopy subscore, 0 or 1) improvement endpoint, which we called histo-endoscopic mucosal healing (or histo-endoscopic mucosal improvement).

RESULTS

Histologic improvement was significantly (P < .0001) associated with clinical remission, lower mean disease activity scores, and greater improvement in disease activity at the end of induction and maintenance studies. Ustekinumab induced and maintained significantly higher rates of histologic improvement at induction week 8 and maintenance week 44 than placebo when more stringent definitions of histologic improvement were used. Histologic improvement and endoscopic improvement following induction were associated with 10% to 20% higher rates of histo-endoscopic mucosal healing, clinical remission, and corticosteroid-free remission at week 44 (all P < .05) in patients who received ustekinumab maintenance therapy. At week 44, 61% of patients (56/92) with histo-endoscopic mucosal healing after induction therapy achieved clinical remission, versus 39% of patients (9/23, P = .0983) and 34% of patients (24/71, P = .0009) with endoscopic or histologic improvement alone after induction, respectively.

CONCLUSION

Data from the UNIFI program of ustekinumab in patients with UC treated with ustekinumab indicated the achievement of histo-endoscopic mucosal healing after induction therapy is associated with lower disease activity at the end of maintenance therapy than either histologic or endoscopic improvement alone. ClinicalTrials.gov number: NCT02407236.

Histologic Healing in Ulcerative Colitis: Benefits. And Risks. Was Voltaire Right?

Histologic healing is emerging as a goal in ulcerative colitis, and the FDA will now require it for a claim of “mucosal healing.” However, issues identified in this editorial, including definitions, protocols, and clinical relevance, will need to be addressed.

Transperineal ultrasound predicts endoscopic and histological healing in ulcerative colitis

BACKGROUND

Transabdominal ultrasound is useful to assess inflammation in patients with ulcerative colitis (UC); however, the assessment of the rectum is challenging and a barrier for its widespread use.

AIM

To evaluate if transperineal ultrasound is useful for predicting endoscopic and histological findings of the rectum in UC.

METHODS

Fifty-three consecutive adults with UC who required colonoscopy were included and transperineal ultrasound was performed in combination with transabdominal ultrasound within a week before or after colonoscopy with rectal biopsy. Mayo endoscopic subscore (MES) ≤1 was defined as endoscopic healing and Geboes score <2.1, Robarts histopathology index ≤6, and Nancy index ≤1 were defined as histological healing. Limberg score and bowel wall thickness were recorded with transperineal ultrasound. Faecal calprotectin was also measured.

RESULTS

Excellent correlation was confirmed between colonoscopy and transabdominal ultrasound in all segments except for the rectum. Rectal bowel wall thickness and Limberg score in transperineal ultrasound well correlated with rectal MES and histological indices. Bowel wall thickness ≤4 mm predicted endoscopic (Area under the curve [AUC] = 0.90) and histological (AUC = 0.87-0.89) healing. In multivariable logistic regression analysis, only bowel wall thickness in transperineal ultrasound was a significant independent predictor for rectal endoscopic and histologic healing (P < 0.05) and the predictability was better than faecal calprotectin.

CONCLUSIONS

Transperineal ultrasound predicts endoscopic and histological healing of the rectum. The combination of transperineal ultrasound with transabdominal ultrasound visualises the entire colorectum and is an ideal modality for the treat-to-target strategy. Clinical Trials Registry number UMIN000033611 (https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000038323).

Long-term deep remission during maintenance therapy with biological agents in inflammatory bowel diseases

Background and aims: A multicentre, retrospective, non-interventional, patient chart review study was conducted to investigate deep (DR) and histological remission rates during maintenance therapy with biological agents in inflammatory bowel disease (IBD).Methods: We reviewed clinical, endoscopic, and histological findings, and laboratory markers such as C-reactive protein (CRP) and faecal calprotectin (FC) on average of nine years after the initiation of anti-TNF-therapy. DR was defined as no clinical symptoms (The physicians' global assessment scores; PGA = 0) with endoscopic remission (the Simple Endoscopic Score for Crohn's Disease [SES-CD] ≤ 2 or Mayo endoscopic subscore ≤1). Histological activity was defined as normal if only architectural alterations without cellularity changes occurred.Results: Of 117 IBD patients on maintenance therapy, 72 (62%; CD n = 55 [56%], UC n = 17 [85%]) patients were in DR. Of patients in DR, 76% were also in histological remission. 77% of patients remained on initiated biological treatment. UC patients achieved DR significantly more often than CD patients (p = .016). Both median CRP and FC levels were significantly lower in patients with DR.Conclusion: Reassuringly, almost two thirds of the IBD patients on maintenance therapy with biological agents maintained DR in the long-term, and more than two thirds of patients in DR achieved also histological remission. CD patients in DR had fewer surgical operations due to CD than patients not achieving DR.

Ustekinumab as Induction and Maintenance Therapy for Ulcerative Colitis

BACKGROUND

The efficacy of ustekinumab, an antagonist of the p40 subunit of interleukin-12 and interleukin-23, as induction and maintenance therapy in patients with ulcerative colitis is unknown.

METHODS

We evaluated ustekinumab as 8-week induction therapy and 44-week maintenance therapy in patients with moderate-to-severe ulcerative colitis. A total of 961 patients were randomly assigned to receive an intravenous induction dose of ustekinumab (either 130 mg [320 patients] or a weight-range-based dose that approximated 6 mg per kilogram of body weight [322]) or placebo (319). Patients who had a response to induction therapy 8 weeks after administration of intravenous ustekinumab were randomly assigned again to receive subcutaneous maintenance injections of 90 mg of ustekinumab (either every 12 weeks [172 patients] or every 8 weeks [176]) or placebo (175). The primary end point in the induction trial (week 8) and the maintenance trial (week 44) was clinical remission (defined as a total score of ≤2 on the Mayo scale [range, 0 to 12, with higher scores indicating more severe disease] and no subscore >1 [range, 0 to 3] on any of the four Mayo scale components).

RESULTS

The percentage of patients who had clinical remission at week 8 among patients who received intravenous ustekinumab at a dose of 130 mg (15.6%) or 6 mg per kilogram (15.5%) was significantly higher than that among patients who received placebo (5.3%) (P<0.001 for both comparisons). Among patients who had a response to induction therapy with ustekinumab and underwent a second randomization, the percentage of patients who had clinical remission at week 44 was significantly higher among patients assigned to 90 mg of subcutaneous ustekinumab every 12 weeks (38.4%) or every 8 weeks (43.8%) than among those assigned to placebo (24.0%) (P = 0.002 and P<0.001, respectively). The incidence of serious adverse events with ustekinumab was similar to that with placebo. Through 52 weeks of exposure, there were two deaths (one each from acute respiratory distress syndrome and hemorrhage from esophageal varices) and seven cases of cancer (one each of prostate, colon, renal papillary, and rectal cancer and three nonmelanoma skin cancers) among 825 patients who received ustekinumab and no deaths and one case of cancer (testicular cancer) among 319 patients who received placebo.

CONCLUSIONS

Ustekinumab was more effective than placebo for inducing and maintaining remission in patients with moderate-to-severe ulcerative colitis. (Funded by Janssen Research and Development; UNIFI ClinicalTrials.gov number, NCT02407236.).