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SummaryBackgroundAccurate estimates for the risk of COVID‐19 in IBD, and an understanding of the impact of COVID‐19 on IBD course and the risk of incident post‐infectious IBD are needed.AimsTo estimate the risk of COVID‐19 in IBD and study its impact on IBD course and the risk of incident post‐infectious IBD.MethodsA retrospective propensity score matched cohort study utilising multi‐institutional research network TriNetX. COVID‐19 patients with and without IBD were identified to quantify the risk of COVID‐19 in patients with IBD, COVID‐19 outcomes in patients with IBD and the impact of COVID‐19 on IBD disease course. The risk of incident post‐infectious IBD in COVID‐19 patients was compared to the population not infected with COVID‐19 during a similar time period.ResultsIncidence rate ratio for COVID‐19 was lower in IBD patients compared to the non‐IBD population (0.79, 95% CI: 0.72‐0.86). COVID‐19‐infected patients with IBD were at increased risk for requiring hospitalisation compared to non‐IBD population (RR: 1.17, 95% CI: 1.02‐1.34) with no differences in need for mechanical ventilation or mortality. Patients with IBD on steroids were at an increased risk for critical care need (RR: 2.22, 95% CI: 1.29‐3.82). Up to 7% of patients with IBD infected with COVID‐19 suffered an IBD flare 3‐months post‐infection. Risk for incident IBD post‐COVID was lower than that seen in the non‐COVID population (RR: 0.64, 95% CI: 0.54‐0.65).ConclusionWe observed no increase in risk for COVID‐19 amongst patients with IBD or risk for de novo IBD after COVID‐19 infection. We confirmed prior observations regarding the impact of steroid use on COVID‐19 severity in patients with IBD.

INTRODUCTION: The optimal instrument for assessing histologic disease activity in patients with eosinophilic esophagitis (EoE) is unclear. We assessed the responsiveness of the EoE Histologic Scoring System (EoE-HSS) when compared with that of the peak eosinophil count (PEC). METHODS: Histopathology slides were obtained from patients with EoE at baseline and after 8 weeks of treatment with swallowed topical budesonide or elimination diet. Two blinded gastrointestinal pathologists scored biopsies on the EoE-HSS, PEC, and 100-mm visual analog scale (VAS) of overall histologic severity. Change was defined as an improvement by ≥0.5 SD in baseline VAS. Responsiveness was quantified using the standardized effect size (SES) and the probability that the index distinguishes a patient with improvement from a patient without improvement, which is the area under the receiver operating characteristic curve (AUC). Longitudinal validity was assessed using Pearson correlations between changes in EoE-HSS and both PEC and VAS. RESULTS: The EoE-HSS grade (SES 2.18 [95% confidence interval, CI: 1.46–2.88]; AUC 0.73 [95% CI: 0.57–0.84]) and stage (SES 2.07 [95% CI: 1.37–2.77]; AUC 0.73 [95% CI: 0.58–0.84]) were highly responsive, similar to PEC (SES 1.44 [95% CI: 0.80–2.07]; AUC 0.73 [95% CI: 0.58–0.84]). The EoE-HSS grade and stage were more highly correlated with changes in VAS (grade 0.92 [95% CI: 0.86–0.95]; stage 0.89 [95% CI: 0.81–0.94]) than with changes in PEC (grade 0.74 [95% CI: 0.58–0.85]; stage 0.66 [95% CI: 0.47–0.80]). DISCUSSION: The EoE-HSS is highly responsive, performs similarly to PEC, and is better correlated with changes in overall histologic activity in patients with EoE.

Intestinal fibrosis is considered an inevitable complication of Crohn’s disease (CD) that results in symptoms of obstruction and stricture formation. Endoscopic or surgical treatment is required to treat the majority of patients. Progress in the management of stricturing CD is hampered by the lack of effective antifibrotic therapy; however, this situation is likely to change because of recent advances in other fibrotic diseases of the lung, liver, and skin. In this review, we summarize data from randomized controlled trials (RCTs) of antifibrotic therapies in these conditions. Multiple compounds have been tested for antifibrotic effects in other organs. According to their mechanisms, they were categorized into growth factor modulators, inflammation modulators, 5-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors, intracellular enzymes and kinases, renin-angiotensin system (RAS) modulators, and others. From our review of the results from the clinical trials and discussion of their implications in the gastrointestinal tract, we have identified several molecular candidates that could serve as potential therapies for intestinal fibrosis in CD.

Abstract Background The histologic assessment of inflammatory bowel disease (IBD) relies on qualitative grading methods. Although widely accepted, these instruments are time consuming, require specialized training, and suffer from inter-rater disagreement. For these reasons there is a need for more consistent and less biased methods to assess IBD histology. Methods The algorithm was initially developed using hematoxylin and eosin (H&E) stained whole slide images of colon biopsies (238 ulcerative colitis [UC], 30 Crohn’s Disease [CD], and 28 endoscopically normal adjacent [ENA]). The first two stages implement convolutional neural networks (CNN) which segment 11 key anatomical features (Figure 1). The third stage extracts the features and models them for prediction. Results The first stage of the algorithm was validated on an independent test dataset by calculating the intersection-over-union (IoU) for the ground truth and prediction masks, resulting in a value of 0.97. A preliminary validation for stage 2 was performed by randomly selecting 30 unique biopsy sections from the test dataset and applying a 150um x 150um counting frame. An expert gastrointestinal pathologist confirmed correct cell identification by the algorithm for three of the primary inflammatory cell types: plasma cells, eosinophils, and neutrophils which resulted in a sensitivity/specificity of 0.76/0.99, 0.78/1.00, and 1.00/0.98 respectively. The final stage predicts RHI grades which could be directly compared to pathologist reads (Figure 2, 3, and 4). Conclusion This is the first study to demonstrate the value of machine learning to assess histologic activity in IBD. These methods lay the foundations for future work, and we believe stages 1 and 2 can be explored independently to statistically characterize the histologic changes of IBD, enabling the improvement of preexisting grading systems.

Abstract Background We studied the efficacy and safety of ustekinumab (UST) vs adalimumab (ADA) through 1 year in biologic-naïve patients (pts) with moderate-to-severe Crohn’s disease. Methods SEAVUE was a multicenter, randomized, blinded, parallel-group, active-controlled study in adults with CD Activity Index (CDAI) scores ≥220/≤450. Biologic-naïve pts failing/intolerant to conventional therapy with any size ulcer on baseline (BL) ileocolonoscopy were eligible. Pts were randomized 1:1 to UST (⁓6mg/kg IV at BL then 90mg SC every 8 weeks [Ws]) or ADA (160/80mg SC at BL/W2, then 40mg SC every 2 Ws) per US-approved regimens (no dose modifications). Primary endpoint was clinical remission at W52 (CDAI <150). Major secondary endpoints were corticosteroid-free remission, clinical response (≥100-point CDAI decrease from BL), remission in pt-reported CDAI components (PRO-2 symptom remission: abdominal pain mean daily score ≤1 and stool frequency mean daily score ≤3), and endoscopic remission (SES-CD score ≤3/0 for pts with BL score=3) at W52 and clinical remission at W16. Results 386 pts were randomized to UST or ADA. BL demographics and disease characteristics were balanced between groups and indicative of pts with early, moderate-to-severe CD (median CD duration, 2.58 years; CDAI, 289.5; SES-CD, 8.0). At W52, 65% of UST-treated and 61% of ADA-treated pts achieved clinical remission (Δ=4.0%; 95% CI, -5.5%, 13.5%; p=0.417). Major secondary endpoints, including endoscopic remission, were similar between groups (Table 1), as were remission rates at assessment points through W52. Some other secondary endpoints showed numerical (not statistical) differences between UST and ADA (Table 1). Key safety events are summarized in Table 2. Among UST-treated and ADA-treated pts, 34.0% and 40.5% had infections, 2.6% and 7.2% had serious adverse events (AEs) of worsening CD, and 6.3% and 11.3% had AEs that led to discontinuation (DC) of study drug, respectively. One ADA-treated pt had active pulmonary TB. Injection-site reactions associated with active treatment occurred in 1.0% of UST-treated and 10.3% of ADA-treated pts. Overall, 15.2% of UST-treated and 23.6% of ADA-treated pts DC before W52. Reasons for DC were primarily lack of efficacy (UST, 2.1% vs ADA, 5.1%), AEs (UST, 5.7% vs ADA, 10.7%), and withdrawal of consent (UST, 5.8% vs ADA, 5.1%). Time to treatment DC was longer with UST vs ADA (post hoc analysis). Conclusion Both UST and ADA were highly effective in this population of biologic-naïve pts. Rates of clinical remission at W52 were not statistically significantly different between treatment groups. DC rates were numerically lower for UST. Safety results were consistent with prior experience for both treatments.

Objective Effective medical therapy and validated trial outcomes are lacking for small bowel Crohn’s disease (CD) strictures. Histopathology of surgically resected specimens is the gold standard for correlation with imaging techniques. However, no validated histopathological scoring systems are currently available for small bowel stricturing disease. We convened an expert panel to evaluate the appropriateness of histopathology scoring systems and items generated based on panel opinion. Design Modified RAND/University of California Los Angeles methodology was used to determine the appropriateness of 313 candidate items related to assessment of CD small bowel strictures. Results In this exercise, diagnosis of naïve and anastomotic strictures required increased bowel wall thickness, decreased luminal diameter or internal circumference, and fibrosis of the submucosa. Specific definitions for stricture features and technical sampling parameters were also identified. Histopathologically, a stricture was defined as increased thickness of all layers of the bowel wall, fibrosis of the submucosa and bowel wall, and muscularisation of the submucosa. Active mucosal inflammatory disease was defined as neutrophilic inflammation in the lamina propria and any crypt or intact surface epithelium, erosion, ulcer and fistula. Chronic mucosal inflammatory disease was defined as crypt architectural distortion and loss, pyloric gland metaplasia, Paneth cell hyperplasia, basal lymphoplasmacytosis, plasmacytosis and fibrosis, or prominent lymphoid aggregates at the mucosa/submucosa interface. None of the scoring systems used to assess CD strictures were considered appropriate for clinical trials. Conclusion Standardised assessment of gross pathology and histopathology of CD small bowel strictures will improve clinical trial efficiency and aid drug development.

Abstract Intratumoral genomic heterogeneity in glioblastoma (GBM) is a barrier to overcoming radiation (RT) resistance. To discover genotype-independent mediators of RT resistance, we correlated RT resistance with the concentration of approximately 700 metabolites across 23 GBM cell lines. Purine metabolites, especially those containing the base guanine, were most correlated with RT resistance. Similarly, increased abundance of tumor purines was associated with decreased survival in GBM patients treated with RT. This relationship is causal. Purine supplementation protected RT-sensitive GBMs from RT and promoted the repair of RT-induced double strand DNA breaks (DSBs). In vitro and in vivo stable isotope tracing confirmed that GBM cell lines and orthotopic patient-derived xenografts primarily generated purines through the de novo synthetic pathway. RT treatment further increased de novo purine synthesis in GBM through signaling via the DNA damage response. Inhibition of de novo GTP synthesis with mycophenolic acid (MPA) sensitized multiple GBM cell lines and neurospheres to RT by slowing the repair of RT-induced DSBs. MPA-induced radiosensitization was GTP-dependent as it was rescued by nucleoside supplementation. Modulating pyrimidine metabolism affected neither RT resistance nor DSB repair, suggesting these GTP-specific effects are due to active signaling rather than its ability to act as a physical substrate for DNA repair and candidate signaling molecules have been identified. These results were recapitulated in vivo with mycophenolate mofetil (MMF), the orally bioavailable FDA-approved prodrug of MPA. MMF potentiated RT efficacy, reduced tumor guanylates and slowed the repair of RT-induced DSBs across multiple models. Because de novo purine synthesis is activated by many of the oncogenic alterations that drive GBM, its inhibition is a promising genotype-independent strategy to overcome GBM RT resistance. We have now begun a clinical trial to determine whether combining MMF and RT is safe and potentially efficacious in patients with GBM.