Microscopic heterogeneity in ulcerative colitis: implications for microscopic measurement of disease activity

Histologic Disease Persists beyond Mucosal Healing and Could Predict Reactivation in Ulcerative Colitis

Mucosal healing (MH) is the main target in ulcerative colitis (UC) treatment. Even if MH lowers the risk of disease reactivation, some patients still relapse. Histologic activity (HA) beyond MH could explain these cases. This study aims to assess how many patients with MH have HA and which lesions are associated with relapse. We retrospectively enrolled UC patients showing MH, expressed as a Mayo Endoscopic Subscore (MES) of 0 and 1 upon colonoscopy. We reviewed the histological reports of biopsies evaluating the presence of typical lesions of UC and assessed the number of clinical relapses after 12 months. Among 100 enrolled patients, 2 showed no histological lesions. According to univariate analysis, patients with a higher number of histological lesions at the baseline had a higher risk of relapse (OR 1.25, p = 0.012), as well as patients with basal plasmacytosis (OR 4.33, p = 0.005), lamina propria eosinophils (OR 2.99, p = 0.047), and surface irregularity (OR 4.70, p = 0.010). However, in the multivariate analysis, only basal plasmacytosis (OR 2.98, p = 0.050) and surface irregularity (OR 4.50, p = 0.024) were confirmed as risk factors for disease reactivation. HA persists in a significant percentage of patients with MH. Despite the presence of MH, patients with basal plasmacytosis and surface irregularity have a higher risk of relapse.

Ulcerative colitis: STRIDE-ing beyond symptoms with new standards

The landscape of ulcerative colitis has changed in the last two decades. Advancements in pharmacotherapeutics have heralded the introduction of new treatment options, with many agents in development. Better clinical outcomes are seen with tighter disease control, made possible with greater understanding of inflammatory pathways and their blockade with drugs. There has been a resultant shift in treatment targets, beyond symptoms to endoscopic and histological healing. Controlling the burden of disease activity also lowers the risk of developing colorectal cancer. Colorectal cancer screening now requires the use of dye-based agents and high-definition colonoscopy to improve the detection of colonic neoplasms.

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.

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.

Endoscopic remission assessed with PICaSSO virtual electronic chromendoscopy accurately predicts clinical outcomes in ulcerative colitis

BACKGROUND AND AIMS

A composite endoscopic-histologic remission is increasingly explored as an important endpoint in ulcerative colitis (UC). We investigated combined endoscopic-histologic remission for predicting clinical outcomes at 12 months compared with endoscopic remission alone using the high definition virtual chromoendoscopy (VCE) Paddington International virtual ChromoendoScopy ScOre (PICaSSO) and histology scores.

METHODS

Ulcerative colitis patients, prospectively enrolled from 11 international centres, underwent VCE with targeted biopsies and followed up for 12 months. Endoscopic activity was assessed by Mayo Endoscopic Score (MES), Ulcerative Colitis Endoscopic Index Severity (UCEIS) followed by VCE-PICaSSO. Robarts Histopathological Index|Robarts Histological index≤3 without neutrophils in mucosa, and Nancy Histological index (NHI)≤ 1 were used to define histologic remission. Combined endoscopic-histologic remission was compared with endoscopic remission alone by Cox proportional hazards model and by two- and three-proportion analysis using pre-specified clinical outcomes.

RESULTS

307 patients were recruited and 302 analysed. There was no difference in survival without specified clinical outcomes between PICaSSO defined endoscopic remission alone and endoscopic plus histologic remission in the rectum (HR 0.42, 95%CI 0.16-1.11 and HR 1.03, 95%CI 0.42-2.52 for Robarts Histological index and NHI respectively) at 12 months. There was however a significant survival advantage without specified clinical outcome events for UCEIS combined with histology compared with UCEIS alone (HR 0.30, 95%CI 0.12-0.75, p = 0.02) at 12 months (but not combined with NHI). For MES there was no advantage for predicting specified clinical outcomes at 12 months for endoscopy alone versus endoscopy plus histology, but there were differences in two and three proportion analysis at 6 months.

CONCLUSION

Endoscopic remission by VCE-PICaSSO alone was similar to combined endoscopic and histologic remission for predicting specified clinical outcomes at 12 months. Larger studies with specific therapeutic interventions are required to further confirm the findings.

Histologic Outcomes With Vedolizumab Versus Adalimumab in Ulcerative Colitis: Results From An Efficacy and Safety Study of Vedolizumab Intravenous Compared to Adalimumab Subcutaneous in Participants With Ulcerative Colitis (VARSITY)

BACKGROUND AND AIMS

VARSITY (An Efficacy and Safety Study of Vedolizumab Intravenous [IV] Compared to Adalimumab Subcutaneous [SC] in Participants With Ulcerative Colitis) showed superior clinical remission and endoscopic improvement in ulcerative colitis with vedolizumab vs adalimumab. This analysis compared histologic outcomes.

METHODS

Patients in VARSITY were randomized 1:1 to maintenance with vedolizumab IV 300 mg every 8 weeks or adalimumab SC 40 mg every 2 weeks (both following standard induction). Geboes Index and Robarts Histopathology Index (RHI) scores were used to assess prespecified histologic exploratory end points of histologic remission (Geboes <2 or RHI ≤2) and minimal histologic disease activity (Geboes ≤3.1 or RHI ≤4) at weeks 14 and 52.

RESULTS

In total, 769 patients received vedolizumab (n = 383) or adalimumab (n = 386). Mean baseline histologic disease activity was similar between vedolizumab and adalimumab groups. Vedolizumab induced greater histologic remission than adalimumab at week 14 (Geboes: 16.7% vs 7.3%, Δ9.4% [95% confidence interval {CI}, 4.9%-13.9%], P < .0001; RHI: 25.6% vs 16.1%, Δ9.5% [95% CI, 3.8%-15.2%], P = .0011) and week 52 (Geboes: 29.2% vs 8.3%, Δ20.9% [95% CI, 15.6%-26.2%], P < .0001; RHI: 37.6% vs 19.9%, Δ17.6% [95% CI, 11.3%-23.8%], P < .0001) overall and in both anti-tumor necrosis factor (TNF)-naïve and -failure subgroups. Results were similar for minimal histologic disease activity. Histologic outcomes were generally better in anti-TNF-naïve vs -failure patients. At week 52, rates of mucosal healing (composite end point of histologic plus endoscopic improvement) were also higher with vedolizumab than adalimumab (Geboes: 25.6% vs 6.7%; RHI: 30.5% vs 14.5%).

CONCLUSIONS

Higher rates of histologic remission, minimal histologic disease activity, and combined histologic plus endoscopic outcomes were observed with vedolizumab than with adalimumab in ulcerative colitis in both anti-TNF-naïve and -failure subgroups.

REGISTRATION

ClinicalTrials.gov NCT02497469; EudraCT 2015-000939-33.

Variability in the Distribution of Histological Disease Activity in the Colon of Patients with Ulcerative Colitis

BACKGROUND AND AIMS

Histological activity scores have been developed and validated. However, data on the distribution of histological inflammation within one segment in patients with ulcerative colitis [UC] are lacking. This impacts on the reliability of histological activity scores. The aim of this study was to assess the variability in histological activity within one endoscopic segment in patients with UC.

METHODS

Biopsies were taken in sequential patients with UC in three adjacent contiguous regions within a macroscopically homogeneous colonic segment. Biopsies were scored for Geboes score [GS], Robarts histological index [RHI] and Nancy histological index [NHI]. Variability was assessed by Kappa statistics for categorical outcomes and intraclass correlation coefficient [ICC] for continuous outcomes.

RESULTS

A total of 161 biopsy sets from 55 endoscopic segments of 21 patients were analysed. Endoscopically active disease was present in 45% of segments. The continuous histological scores showed excellent agreement between the different regions. The ICC for RHI in all segments was 0.974 (95% confidence interval [CI] 0.958-0.984; p < 0.0001) and 0.98 [95% CI: 0.968-0.988; p < 0.0001] for the numerically converted GS. The categorical NHI showed higher variability: κ = 0.574 [95% CI: 0.571-0.577; p < 0.0001]. In all segments the highest variability was seen in samples with NHI = 2. When dichotomizing based on histological remission, substantial agreement was seen for all scores, with κ > 0.734 for all cut-offs. The homogeneity in the distribution of histological disease activity was comparable between colonic segments.

CONCLUSION

The distribution of histological disease activity in UC follows a homogeneous pattern in different locations of one segment.

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

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

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

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

Treat-to-Target in Inflammatory Bowel Diseases, What Is the Target and How Do We Treat?

Inflammatory bowel diseases, including Crohn disease (CD) and ulcerative colitis (UC), are chronic, progressive, immune-mediated inflammatory diseases of the gastrointestinal tract. Early therapy using a treat-to-target (T2T) approach, which implies identification of a pre-defined target, followed by optimization of therapy and regular monitoring until the goal is achieved is critical in preventing adverse long-term outcomes. In this review, the authors discuss the T2T guidance developed by the Selecting Therapeutic Targets in Inflammatory Bowel Disease committee, new evidence published on the role of various targets in CD and UC, as well as the real-world applicability of T2T."