SummaryBackgroundThe optimal ulcerative colitis biopsy protocol is unclear.AimTo evaluate the number of biopsies required to accurately assess microscopic disease activity in ulcerative colitisMethodsBiopsies from patients with ≥4 rectosigmoid samples, and clinical and endoscopic data, were retrospectively obtained from a prospective biobank. Histology and endoscopic videos were read blindly. A 4‐biopsy Robarts Histopathology Index (RHI) reference score, consisting of the worst item‐level ratings from four biopsies, was compared to 1‐, 2‐ and 3‐biopsy estimates. Agreement was determined using bivariate errors‐in‐variable regression analysis (acceptance interval: ±8.25). Endoscopic activity and disease location subgroup analyses were also performed.ResultsForty‐six patients had ≥4 rectosigmoid biopsies available (N = 287). The 2‐biopsy (tolerance interval: −7.66, 4.79) and 3‐biopsy (tolerance interval: −4.86, 3.46) RHI scores demonstrated acceptable agreement with 4‐biopsy scores. One‐biopsy scores demonstrated unacceptable agreement (tolerance interval: −13.99, 7.78). Mean RHI scores using the 2‐, 3‐ and 4‐biopsy approaches were similar (6.1 ± 9.6 P = 0.36; 6.8 ± 10.5, P = 0.7; 7.5 ± 11.2), whereas the 1‐biopsy estimate was lower (4.4 ± 8.1, P = 0.06). Histological remission rates were identical for the 2‐, 3‐ and 4‐biopsy methods (65.2%, P = 1.0). Subgroup analysis demonstrated that three biopsies were required in patients with endoscopically active disease. Sampling additional colonic locations yielded lower histological remission rates compared to rectosigmoid sampling alone (33.3% vs 61.9%, P = 0.1).ConclusionsA minimum of two — conservatively, three — biopsies are required to reliably assess disease activity in a single colonic segment using the RHI. Further studies are needed of endoscopically active patients and sampling locations. These results have implications for biopsy strategies in clinical trials and practice.
Editorial: protecting hypoxia‐inducible factor 1a and gut integrity with GB004—a promising therapeutic approach for ulcerative colitis? Authors' reply
LINKED CONTENTThis article is linked to Danese et al papers. To view these articles, visit https://doi.org/10.1111/apt.16753 and https://doi.org/10.1111/apt.16761
Randomised clinical trial: a phase 1b study of GB004, an oral HIF‐1α stabiliser, for treatment of ulcerative colitis
SummaryBackgroundEpithelial barrier dysfunction contributes to a dysregulated intestinal immune response in ulcerative colitis (UC). GB004 is an orally administered, small molecule, gut‐targeted stabiliser of hypoxia‐inducible factor‐1α, a transcription factor with protective roles at the epithelial layer of the inflamed gut.AimsTo evaluate safety, pharmacokinetics, pharmacodynamics and efficacy of GB004 in patients with active UC.MethodsThis double‐blind, placebo‐controlled study randomised patients 2:1 to receive an oral solution of GB004 120 mg or placebo once daily for 28 days. Eligible patients had a Robarts Histopathology Index score ≥4 with neutrophils in the epithelium, total Mayo Clinic score 3‐12, Mayo Clinic endoscopic subscore ≥1, and blood in the stool, despite treatment with 5‐aminosalicylates, corticosteroids or immunosuppressants.ResultsThirty‐four patients were randomised. GB004 120 mg for 28 days was generally well‐tolerated. Adverse events occurred in 27.3% (3/11) and 39.1% (9/23) of patients in the placebo and GB004 groups respectively. Nausea and dysgeusia were most commonly reported in the GB004 group (0% for placebo and 21.7% [5/23] and 13.0% [3/23] respectively for GB004). There were no treatment‐related serious adverse events or deaths. GB004 exhibited minimal accumulation, with higher colonic concentrations relative to plasma. Exploratory pharmacodynamic and efficacy analyses demonstrated GB004 target engagement and numerically higher proportions of patients achieving improvement in multiple measures of disease activity, respectively, at day 28 for GB004 compared to placebo.ConclusionResults from this phase 1b trial support evaluation of the full therapeutic potential of GB004 for the treatment of UC. A phase 2 study (NCT04556383) is ongoing. Clinicaltrials.gov NCT03860896.
Evaluation of optimal biopsy location for assessment of histological activity, transcriptomic and immunohistochemical analyses in patients with active Crohn’s disease
SummaryBackgroundThe appropriate location for biopsy procurement relative to an ulcer in active Crohn's disease is unknown.AimTo explore the relationship between biopsy location, histological disease activity, proinflammatory gene expression and the presence of inflammatory cells.MethodsFifty‐one patients with Crohn's disease and ulcers >0.5 cm diameter in the colon and/or ileum were prospectively enrolled at three centres. Biopsies were obtained from 0 mm, 7 to 8 mm and 21 to 24 mm from the edge of the largest ulcer. Histological activity was blindly assessed with the Global Histological Disease Activity Score, the Robarts Histopathology and Nancy Histological indices. Messenger ribonucleic acid (mRNA) levels for interleukins‐6, ‐8 and ‐23 (p19 and p40 subunits), CD31 and S100A9 were measured using quantitative polymerase chain reaction. The number of CD3+, CD68+ and myeloperoxidase‐positive cells was quantified by immunohistochemistry. Data were analysed using mixed models with location and segment as fixed effects and patients as random effect to account for correlation among segments within a patient.ResultsHistological disease activity scores (P < 0.0001), proinflammatory gene expression levels (P < 0.005) and numbers of myeloperoxidase‐positive cells (P < 0.0001) were highest in biopsies from the ulcer edge in the colon and ileum, with decreasing gradients observed with distance from the edge (P < 0.05). No differences between colonic and ileal samples were detected for the parameters measured at any location.ConclusionsBiopsies from the ulcer edge in patients with Crohn's disease yielded the greatest histological disease activity and mRNA levels and had similar readouts in the colon and ileum. Research is needed to confirm this conclusion for other measures.
Systematic review and network meta‐analysis: first‐ and second‐line biologic therapies for moderate‐severe Crohn's disease
SummaryBackgroundThere are limited data to inform positioning of agents for treating moderate‐severe Crohn's disease (CD).AimWe assessed comparative efficacy and safety of first‐line (biologic‐naïve) and second‐line (prior exposure to anti‐tumour necrosis factor [TNF]‐α) agents) biologic therapy for moderate‐severe CD, through a systematic review and network meta‐analysis, and appraised quality of evidence (QoE) using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.MethodsWe identified randomised controlled trials (RCTs) in adults with moderate‐severe CD treated with approved anti‐TNF agents, anti‐integrin agents and anti‐IL12/23 agents, first‐line or second‐line, and compared with placebo or another active agent. Efficacy outcomes were induction and maintenance of clinical remission; safety outcomes were serious adverse events and infections. Network meta‐analyses were performed, and ranking was assessed using surface under the cumulative ranking (SUCRA) probabilities.ResultsNo head‐to‐head trials were identified. In biologic‐naïve patients, infliximab (SUCRA,0.93) and adalimumab (SUCRA,0.75) were ranked highest for induction of clinical remission (moderate QoE). In patients with prior anti‐TNF exposure, adalimumab (SUCRA, 0.91; low QoE, in patients with prior response or intolerance to anti‐TNF agents) and ustekinumab (SUCRA, 0.71) were ranked highest for induction of clinical remission. In patients with response to induction therapy, adalimumab (SUCRA, 0.97) and infliximab (SUCRA, 0.68) were ranked highest for maintenance of remission. Ustekinumab had lowest risk of serious adverse events (SUCRA, 0.72) and infection (SUCRA, 0.71; along with infliximab, SUCRA, 0.83) in maintenance trials.ConclusionIndirect comparisons suggest that infliximab or adalimumab may be preferred first‐line agents, and ustekinumab a preferred second‐line agent, for induction of remission in patients with moderate‐severe CD. Head‐to‐head trials are warranted.
Systematic review with meta‐analysis: endoscopic and histologic placebo rates in induction and maintenance trials of ulcerative colitis
Summary Background Regulatory requirements for claims of mucosal healing in ulcerative colitis ( UC ) will require demonstration of both endoscopic and histologic healing. Quantifying these rates is essential for future drug development. Aims To meta‐analyse endoscopic and histologic placebo response and remission rates in UC randomised controlled trials ( RCT s) and identify factors influencing these rates. Methods MEDLINE , EMBASE and the Cochrane Library were searched from inception to March 2017 for placebo‐controlled trials of pharmacological interventions for UC . Endoscopic and histologic placebo rates were pooled by random effects. Mixed effects univariable and multivariable meta‐regression was used to evaluate the influence of patient, intervention and trial‐related study‐level covariates on these rates. Results Fifty‐six induction (placebo n = 4171) and 8 maintenance trials (placebo n = 1011) were included. Pooled placebo endoscopic remission and response rates for induction trials were 23% [95 confidence interval ( CI ) 19‐28%] and 35% [95% CI 27‐42%] respectively, and 20% [95% CI 16‐24%] for maintenance of remission. The pooled histologic placebo remission rate was 14% [95% CI 8‐22%] for induction trials. High heterogeneity was observed for all outcomes ( I 2 56.2%‐88.3%). On multivariable meta‐regression, central endoscopy reading was associated with significantly lower endoscopic placebo remission rates (16% vs 25%; OR = 0.52, [95% CI 0.29‐0.92], P = 0.03). On univariable meta‐regression, higher histologic placebo remission was associated with concomitant corticosteroids ( OR = 1.17 [95% CI 1.08‐1.26], P < 0.0001, per 10% increase in corticosteroid use). Conclusions Placebo endoscopic and histologic rates range from 14% to 35% in UC RCT s but are highly heterogeneous. Outcome standardisation may reduce heterogeneity and is needed in this field.