Clinical trial: Randomized controlled trial of linaclotide in children aged 6-17 years with functional constipation

OBJECTIVES

Linaclotide, a guanylate cyclase-C agonist, was recently approved in the United States for treatment of children 6-17 years old with functional constipation (FC). This study evaluated the safety and efficacy of several linaclotide doses in children 6-17 years old with FC.

METHODS

In this multicenter, randomized, double-blind, placebo-controlled phase 2 study, 173 children with FC (based on Rome III criteria) were randomized to once-daily linaclotide (A: 9 or 18 μg, B: 18 or 36 μg, or C: 36 or 72 μg) or placebo in a 1:1:1:1 ratio for 6- to 11-year-olds (dosage determined by weight: 18 to <35 or ≥35 kg) and linaclotide (18, 36, 72, or 145 μg) or placebo in a 1:1:1:1:1 ratio for 12- to 17-year-olds. The primary efficacy endpoint was change from baseline in weekly spontaneous bowel movement (SBM) frequency throughout the 4-week treatment period. Adverse events (AE), clinical laboratory values, and electrocardiograms were monitored.

RESULTS

Efficacy and safety were assessed in 173 patients (52.0% aged 6-11 years; 48.0% aged 12-17 years); 162 (93.6%) completed the treatment period. A numerical improvement in mean SBM frequency was observed with increasing linaclotide doses (1.90 in 6- to 11-year-olds [36 or 72 μg] and 2.86 in 12- to 17-year-olds [72 μg]). The most reported treatment-emergent AE was diarrhea, with most cases being mild; none were severe.

CONCLUSIONS

Linaclotide was well tolerated in this pediatric population, with a trend toward efficacy in the higher doses, warranting further evaluation.

Fitness-for-use of Retrospective Multicenter Electronic Health Records to Conduct Outcome Analysis for Pediatric Ulcerative Colitis

The use of electronic health records has garnered interest as an approach for conducting innovative outcome research and producing real-world evidence at a reduced cost compared to traditional clinical trials. The study aimed to evaluate the utility of deidentified EHR data from a multicenter research network to identify characteristics associated with treatment escalation (TE) in newly diagnosed pediatric ulcerative colitis patients. EHR data (01/2010-12/2021) from 13 Midwest healthcare systems (Greater Plains Collaborative) were collected for pediatric ulcerative colitis patients. We identified standard treatments, excluded missing initial therapy data, and analyzed the TE and time-to-TE outcomes. The clinical and laboratory characteristics at baseline were extracted. Logistic and Cox models were used, and the missing risk factors were imputed. Machine-learning Bayesian additive regression trees were also utilized to create partial dependence plots for assessing the associations between risk factors and clinical outcomes. A total of 502 eligible pediatric patients (aged 4-17 years) who initiated standard treatment were identified. Among them, 205 out of 502 (41%) experienced TE, with a median (P25, P75) duration of 63 (9, 237) days after the initial treatment. Additionally, 20 out of 509 (4%) patients underwent colectomy (COL) with a median (P25, P75) duration of 80 (3, 205) days. Both multivariable logistic regression and Cox proportional hazards regression demonstrated moderate discriminative power in predicting TE and time-to-TE, respectively. Common positive predictors for both TE and time-to-TE included a high monocyte proportion and elevated platelet counts. Conversely, BMI z-score, albumin, hemoglobin levels, and lymphocyte proportion were negatively associated with both TE and time-to-TE. This study demonstrates that multicenter EHR data can be used to identify a trial-comparable study sample of potentially larger size and to identify clinically meaningful endpoints for conducting outcome analysis and generating real-world evidence.

A comparison of Bayesian and frequentist approaches to incorporating clinical and biological information for the prediction of response to standardized pediatric colitis therapy

BACKGROUND

The prospective cohort study PROTECT is the largest study in pediatric ulcerative colitis (UC) with standardized treatments, providing valuable data for predicting clinical outcomes. PROTECT and previous studies have identified characteristics associated with clinical outcomes. In this study, we aimed to compare predictive modeling between Bayesian analysis including machine learning and frequentist analysis.

METHODS

The key outcomes for this analysis were week 4, 12 and 52 corticosteroid (CS)-free remission following standardized treatment from diagnosis. We developed predictive modeling with multivariable Bayesian logistic regression (BLR), Bayesian additive regression trees (BART) and frequentist logistic regression (FLR). The effect estimate of each risk factor was estimated and compared between the BLR and FLR models. The predictive performance of the models was assessed including area under curve (AUC) of the receiver operating characteristic (ROC) curve. Ten-fold cross-validation was performed for internal validation of the models. The estimation contained 95% credible (or confidence) interval (CI).

RESULTS

The statistically significant associations between the risk factors and early or late outcomes were consistent between all BLR and FLR models. The model performance was similar while BLR and BART models had narrower credible intervals of AUCs. To predict week 4 CS-free remission, the BLR model had AUC of 0.69 (95% CI 0.67-0.70), the BART model had AUC of 0.70 (0.67-0.72), and the FLR had AUC of 0.70 (0.65-0.76). To predict week 12 CS-free remission, the BLR model had AUC of 0.78 (0.77-0.79), the BART model had AUC of 0.78 (0.77-0.79), and the FLR model had AUC of 0.79 (0.74-0.83). To predict week 52 CS-free remission, the BLR model had AUC of 0.69 (0.68-0.70), the BART model had AUC of 0.69 (0.67-0.70), and the FLR model had AUC of 0.69 (0.64-0.74). The BART model identified nonlinear associations.

CONCLUSIONS

BLR and BART models had intuitive interpretation on interval estimation, better precision in estimating the AUC and can be alternatives for predicting clinical outcomes in pediatric patients with UC. BART model can estimate nonlinear nonparametric association.

Efficacy and safety of linaclotide in treating functional constipation in paediatric patients: a randomised, double-blind, placebo-controlled, multicentre, phase 3 trial

BACKGROUND

Linaclotide, a guanylate cyclase C agonist, has been approved in the USA for the treatment of chronic idiopathic constipation and irritable bowel syndrome with predominant constipation in adults. We aimed to assess the efficacy and safety of linaclotide in paediatric patients aged 6-17 years with functional constipation.

METHODS

This randomised, double-blind, placebo-controlled, multicentre, phase 3 study was done at 64 clinic or hospital sites in seven countries (USA, Canada, Israel, Italy, the Netherlands, Ukraine, and Estonia). Patients aged 6-17 years who met modified Rome III criteria for functional constipation were randomly assigned (1:1), with a block size of four and stratified by age (6-11 years and 12-17 years), to receive either oral linaclotide 72 μg or placebo once daily for 12 weeks. Participants, investigators, and data assessors were masked to assignment. The primary efficacy endpoint was change from baseline (CFB) in the 12-week frequency rate of spontaneous bowel movements (SBMs; occurring in the absence of rescue medication on the calendar day of or before the bowel movement) per week and the secondary efficacy endpoint was CFB in stool consistency over the 12-week treatment period; efficacy and safety were analysed in all patients in the randomised population who received at least one dose of study intervention (modified intention-to-treat population and safety population, respectively). The study is registered with ClinicalTrials.gov, NCT04026113, and the functional constipation part of the study is complete.

FINDINGS

Between Oct 1, 2019, and March 21, 2022, 330 patients were enrolled and randomly assigned to linaclotide (n=166) or placebo (n=164). Two patients in the linaclotide group did not receive any treatment; thus, efficacy and safety endpoints were assessed in 328 patients (164 patients in each group). 293 (89%) patients completed the 12-week treatment period (148 in the linaclotide group and 145 in the placebo group). 181 (55%) of 328 patients were female and 147 (45%) were male. At baseline, the mean frequency rate for SBMs was 1·28 SBMs per week (SD 0·87) for placebo and 1·16 SBMs per week (0·83) for linaclotide, increasing to 2·29 SBMs per week (1·99) for placebo and 3·41 SBMs per week (2·76) for linaclotide during intervention. Compared with placebo (least-squares mean [LSM] CFB 1·05 SBMs per week [SE 0·19]), patients treated with linaclotide showed significant improvement in SBM frequency (LSM CFB 2·22 SBMs per week [0·19]; LSM CFB difference 1·17 SBMs per week [95% CI 0·65-1·69]; p<0·0001). Linaclotide also significantly improved stool consistency over placebo (LSM CFB 1·11 [SE 0·08] vs 0·69 [0·08]; LSM CFB difference 0·42 [95% CI 0·21-0·64]; p=0·0001). The most reported treatment-emergent adverse event (TEAE) by patients treated with linaclotide was diarrhoea (seven [4%] of 164 vs three [2%] of 164 patients in the placebo group) and by patients treated with placebo was COVID-19 (five [3%] vs four [2%] in the linaclotide group). The most frequent treatment-related TEAE was diarrhoea (linaclotide: six [4%] patients; placebo: two [1%] patients). One serious adverse event of special interest (treatment-related severe diarrhoea resulting in dehydration and hospitalisation) occurred in a female patient aged 17 years in the linaclotide group; this case resolved without sequelae after administration of intravenous fluids. No deaths occurred during the study.

INTERPRETATION

Linaclotide is an efficacious and well tolerated treatment for functional constipation in paediatric patients and has subsequently been approved by the US Food and Drug Administration for this indication.

FUNDING

AbbVie and Ironwood Pharmaceuticals.

Recommendations for Standardizing MRI-based Evaluation of Perianal Fistulizing Disease Activity in Pediatric Crohn's Disease Clinical Trials

BACKGROUND

Perianal fistulas and abscesses occur commonly as complications of pediatric Crohn's disease (CD). A validated imaging assessment tool for quantification of perianal disease severity and activity is needed to evaluate treatment response. We aimed to identify magnetic resonance imaging (MRI)-based measures of perianal fistulizing disease activity and study design features appropriate for pediatric patients.

METHODS

Seventy-nine statements relevant to MRI-based assessment of pediatric perianal fistulizing CD activity and clinical trial design were generated from literature review and expert opinion. Statement appropriateness was rated by a panel (N = 15) of gastroenterologists, radiologists, and surgeons using modified RAND/University of California Los Angeles appropriateness methodology.

RESULTS

The modified Van Assche Index (mVAI) and the Magnetic Resonance Novel Index for Fistula Imaging in CD (MAGNIFI-CD) were considered appropriate instruments for use in pediatric perianal fistulizing disease clinical trials. Although there was concern regarding the use of intravascular contrast material in pediatric patients, its use in clinical trials was considered appropriate. A clinically evident fistula tract and radiologic disease defined as at least 1 fistula or abscess on pelvic MRI were considered appropriate trial inclusion criteria. A coprimary clinical and radiologic end point and inclusion of a patient-reported outcome were also considered appropriate.

CONCLUSION

Outcomes of treatment of perianal fistulizing disease in children must include MRI. Existing multi-item measures, specifically the mVAI and MAGNIFI-CD, can be adapted and used for children. Further research to assess the operating properties of the indices when used in a pediatric patient population is ongoing.

Safety and efficacy of linaclotide in children aged 7-17 years with irritable bowel syndrome with constipation

OBJECTIVES

Linaclotide, a guanylate cyclase-C agonist, was recently approved in the United States for the treatment of children 6-17 years old with functional constipation. This study evaluated the safety and efficacy of various linaclotide doses in children 7-17 years old with irritable bowel syndrome with constipation (IBS-C).

METHODS

In this 4-week, randomized, double-blind, placebo-controlled, parallel-group, Phase 2 study, children with IBS-C were randomized to once-daily placebo or linaclotide (Dose A: 18 or 36 µg, B: 36 or 72 µg, and C: 72 µg or 145 µg, or 290 µg); those aged 7-11 years in a 1:1:1:1 allocation based on weight (18 to <35 kg:18 µg, 36 µg, or 72 µg; or ≥35 kg: 36 µg, 72 µg, or 145 µg), and those aged 12-17 years in a 1:1:1:1:1 allocation (the higher option of Doses A-C or 290 µg). The primary efficacy endpoint was a change from baseline in 4-week overall spontaneous bowel movement (SBM) frequency rate over the treatment period. Adverse events and clinical laboratory measures were also assessed.

RESULTS

Efficacy, safety, and tolerability were assessed in 101 patients. In the intent-to-treat population, numerical improvement was observed in overall SBM frequency rate with increasing linaclotide doses (A: 1.62, B: 1.52, and C: 2.30, 290 µg: 3.26) compared with placebo. The most reported treatment-emergent adverse events were diarrhea and pain, with most cases being mild and none being severe.

CONCLUSIONS

Linaclotide was tolerated well in this pediatric population, showing numerical improvement in SBM frequency compared with placebo.

Outcomes in Adult Inflammatory Bowel Disease Clinical Trials: Assessment of Similarity Among Participants with Adolescent-Onset and Adult-Onset Disease

BACKGROUND AND AIMS

Most pediatric IBD studies are performed after medications are approved in adults and the majority of participants in these studies are adolescents. We hypothesized that adolescent-onset IBD is not fundamentally different than adult-onset IBD. If this is correct, the value of delaying access to novel drugs in adolescents becomes questioned.

METHODS

Data from 11 randomized, double-blind, placebo-controlled adult phase 2 and 3 trials of 4 biologics were analyzed. Participants were categorized as having adolescent- or adult-onset disease (diagnosed 12 to <18, or ≥18 years). Multivariable modelling explored the association between age at diagnosis and response to treatment after adjustment for disease duration, extent, and severity at baseline. Data from dose arms were pooled to evaluate similarity of therapeutic response between adolescent- and adult-onset IBD within the same trial (not between doses or across trials). Ratios of odds ratios between the two groups were evaluated.

RESULTS

Data from 6,283 study participants (2,575 with Crohn's disease [CD], 3,708 with ulcerative colitis [UC]) were evaluated. Of 2,575 study participants with CD, 325 were 12-<18 years old at diagnosis; 836 participants (32.4%) received placebo. Of 3,708 participants with UC, 221 were 12-<18 years old at diagnosis; 1,212 (33%) were receiving placebo. The majority of the ratios of ORs were within two-fold, suggesting that responses in adolescent and adult-onset participants are generally similar.

CONCLUSION

Data presented lend support for extrapolating efficacy of biologics from adults to adolescents with IBD, which would facilitate earlier labeling and patient access.

Progression of Pediatric Crohn's Disease Is Associated With Anti-Tumor Necrosis Factor Timing and Body Mass Index Z-Score Normalization

BACKGROUND & AIMS

The evolution of complicated pediatric Crohn's disease (CD) in the era of anti-tumor necrosis factor (aTNF) therapy continues to be described. Because CD progresses from inflammatory to stricturing (B2) and penetrating (B3) disease behaviors in a subset of patients, we aimed to understand the risk of developing complicated disease behavior or undergoing surgery in relation to aTNF timing and body mass index z-score (BMIz) normalization.

METHODS

Multicenter, 5-year longitudinal data from 1075 newly diagnosed CD patients were analyzed. Descriptive statistics, univariate and stepwise multivariate Cox proportional hazard regression (CPHR), and log-rank analyses were performed for risk of surgery and complicated disease behaviors. Differential gene expression from ileal bulk RNA sequencing was correlated with outcomes.

RESULTS

Stricturing complications had the largest increase: from 2.98% to 10.60% over 5 years. Multivariate CPHR showed aTNF exposure within 3 months from diagnosis (hazard ratio [HR], 0.33; 95% CI, 0.15-0.71) and baseline L2 disease (HR, 0.29; 95% CI, 0.09-0.92) to be associated with reduced B1 to B2 progression. For children with a low BMIz at diagnosis (n = 294), multivariate CPHR showed BMIz normalization within 6 months of diagnosis (HR, 0.47; 95% CI, 0.26-0.85) and 5-aminosalicyclic acid exposure (HR, 0.32; 95% CI, 0.13-0.81) were associated with a decreased risk for surgery while B2 (HR, 4.20; 95% CI, 1.66-10.65) and B2+B3 (HR, 8.24; 95% CI, 1.08-62.83) at diagnosis increased surgery risk. Patients without BMIz normalization were enriched for genes in cytokine production and inflammation.

CONCLUSIONS

aTNF exposure up to 3 months from diagnosis may reduce B2 progression. In addition, lack of BMIz normalization within 6 months of diagnosis is associated with increased surgery risk and a proinflammatory transcriptomic profile.

Gut Microbiome Composition Is Associated With Future Onset of Crohn's Disease in Healthy First-Degree Relatives

BACKGROUND & AIMS

The cause of Crohn's disease (CD) is unknown, but the current hypothesis is that microbial or environmental factors induce gut inflammation in genetically susceptible individuals, leading to chronic intestinal inflammation. Case-control studies of patients with CD have cataloged alterations in the gut microbiome composition; however, these studies fail to distinguish whether the altered gut microbiome composition is associated with initiation of CD or is the result of inflammation or drug treatment.

METHODS

In this prospective cohort study, 3483 healthy first-degree relatives (FDRs) of patients with CD were recruited to identify the gut microbiome composition that precedes the onset of CD and to what extent this composition predicts the risk of developing CD. We applied a machine learning approach to the analysis of the gut microbiome composition (based on 16S ribosomal RNA sequencing) to define a microbial signature that associates with future development of CD. The performance of the model was assessed in an independent validation cohort.

RESULTS

In the validation cohort, the microbiome risk score (MRS) model yielded a hazard ratio of 2.24 (95% confidence interval, 1.03-4.84; P = .04), using the median of the MRS from the discovery cohort as the threshold. The MRS demonstrated a temporal validity by capturing individuals that developed CD up to 5 years before disease onset (area under the curve > 0.65). The 5 most important taxa contributing to the MRS included Ruminococcus torques, Blautia, Colidextribacter, an uncultured genus-level group from Oscillospiraceae, and Roseburia.

CONCLUSION

This study is the first to demonstrate that gut microbiome composition is associated with future onset of CD and suggests that gut microbiome is a contributor in the pathogenesis of CD.

The State of Clinical Trials in Pediatric Inflammatory Bowel Disease

The gap between available biologic and small molecule therapy for inflammatory bowel disease for children and adults remains large. At present only 2 anti-TNF agents are licensed for pediatric use compared with multiple other agents with different mechanisms of action being used in adults. The reasons are many but largely revolve around the inadequate acceptance of adult efficacy data to children, and the reluctance of industry to commit to early pediatric drug development for fear of inadequate return on investment. We suggest common sense steps that need to be taken to improve this situation.

Mucosal transcriptomics highlight lncRNAs implicated in ulcerative colitis, Crohn's disease, and celiac disease

Ulcerative colitis (UC), Crohn's disease (CD), and celiac disease are prevalent intestinal inflammatory disorders with nonsatisfactory therapeutic interventions. Analyzing patient data-driven cohorts can highlight disease pathways and new targets for interventions. Long noncoding RNAs (lncRNAs) are attractive candidates, since they are readily targetable by RNA therapeutics, show relative cell-specific expression, and play key cellular functions. Uniformly analyzing gut mucosal transcriptomics from 696 subjects, we have highlighted lncRNA expression along the gastrointestinal (GI) tract, demonstrating that, in control samples, lncRNAs have a more location-specific expression in comparison with protein-coding genes. We defined dysregulation of lncRNAs in treatment-naive UC, CD, and celiac diseases using independent test and validation cohorts. Using the Predicting Response to Standardized Pediatric Colitis Therapy (PROTECT) inception UC cohort, we defined and prioritized lncRNA linked with UC severity and prospective outcomes, and we highlighted lncRNAs linked with gut microbes previously implicated in mucosal homeostasis. HNF1A-AS1 lncRNA was reduced in all 3 conditions and was further reduced in more severe UC form. Similarly, the reduction of HNF1A-AS1 ortholog in mice gut epithelia showed higher sensitivity to dextran sodium sulfate-induced colitis, which was coupled with alteration in the gut microbial community. These analyses highlight prioritized dysregulated lncRNAs that can guide future preclinical studies for testing them as potential targets.

Managing pediatric Crohn's disease: recent insights

INTRODUCTION

Children and adolescents with Crohn's disease present unique challenges due to extensive disease at diagnosis and the effect of bowel inflammation on growth. Historical approaches with corticosteroids and immunomodulators are far less effective than early treatment with anti-TNF biologics.

AREAS COVERED

This review covers recent literature delineating the crucial role of early anti-TNF therapy in the treatment of moderate- to- severe Crohn's disease in children and adolescents. The potential risks and benefits of concomitant immunomodulators are discussed, along with therapeutic anti-TNF drug monitoring, and reassessment by endoscopy and cross-sectional imaging to evaluate success beyond symptom control.

EXPERT OPINION

Standard of care therapy for moderate-to-severe pediatric Crohn's disease now entails precision dosing of anti-TNF therapy with periodic reassessment of bowel inflammation. The role of dietary modification continues to evolve. Current and future efforts need to be directed to elucidating ways to predict response to anti-TNF therapy and quickly changing to agents with other mechanisms of action when needed. Inordinate regulatory delays in approval of new therapies approved for adults continue to handicap pediatric clinicians and frequently limits their treatment choices, or forces them to give medications "off label." Only a concerted effort by clinicians, pharma, and regulators will improve this situation.

Development and Validation of the TUMMY-UC: A Patient-Reported Outcome for Pediatric Ulcerative Colitis

BACKGROUND & AIMS

The TUMMY-UC is a patient-reported outcome measure for pediatric ulcerative colitis (UC) with an observer-reported outcome version for children aged <8 years. It includes eight items selected by concept elicitation interviews. We aimed to finalize the TUMMY-UC by cognitive interviews (stage 2) and to evaluate the index for its psychometric properties (stage 3).

METHODS

The TUMMY-UC items were first finalized during 129 cognitive debriefing interviews. Then, in a prospective, multicenter validation study, 84 children who underwent colonoscopy or provided stool for calprotectin completed the TUMMY-UC and various measures of disease activity. Assessments were repeated after 7 and 21 days for evaluating reliability and responsiveness.

RESULTS

During stage 2, the items were formatted with identical structure to ensure conceptual equivalence and weighted based on ranking of importance. In stage 3, the TUMMY-UC total score had excellent reliability in repeated assessments (intraclass correlation coefficient, 0.90; 95% confidence interval, 0.84-0.94). It also had moderate to strong correlations with all constructs of disease activity: r = 0.70 with UC endoscopic index of severity, r = 0.63 with the IMPACT-III questionnaire, r = 0.43 with calprotectin, r = 0.80 with the Pediatric Ulcerative Colitis Activity Index, r = 0.75 with global assessment of disease activity, and r = 0.46 with C-reactive protein (all P < .015). The index had excellent discrimination of disease activity, with a score of <9 defining remission (area under the receiver operating characteristic curve, 0.95; 95% confidence interval, 0.93-0.99). The ΔTUMMY-UC showed high responsiveness and differentiated well between children who experienced changed from those with no change.

CONCLUSIONS

The TUMMY-UC, constructed from patient-reported outcome and observer-reported outcome versions, is a reliable, valid and responsive index that can be now used in practice and clinical trials.

Longitudinal DNA methylation profiling of the rectal mucosa identifies cell-specific signatures of disease status, severity and clinical outcomes in ulcerative colitis cell-specific DNA methylation signatures of UC

BACKGROUND

In peripheral blood, DNA methylation (DNAm) patterns in inflammatory bowel disease patients reflect inflammatory status rather than disease status. Here, we examined DNAm in diseased rectal mucosa from ulcerative colitis (UC) patients, focusing on constituent cell types with the goal of identifying therapeutic targets for UC other than the immune system. We profiled DNAm of rectal mucosal biopsies of pediatric UC at diagnosis (n = 211) and non-IBD control (n = 85) patients and performed epigenome-wide association studies (EWAS) of specific cell types to understand DNAm changes in epithelial, immune and fibroblast cells across disease states, course, and clinical outcomes. We also examined longitudinal analysis on follow-up samples (n = 73), and comparisons were made among patients with clinical outcomes including those undergoing colectomy versus those who did not. Additionally, we included RNA-seq from the same subjects to assess the impact of CpG sites on the transcription of nearby genes during the disease course.

RESULTS

At diagnosis, UC rectal mucosa exhibited a lower proportion of epithelial cells and fibroblasts, and higher proportion of immune cells, in conjunction with variation in the DNAm pattern. While treatment had significant effects on the methylation signature of immune cells, its effects on fibroblasts and epithelial cells were attenuated. Individuals who required colectomy exhibited cell composition and DNAm patterns at follow-up more similar to disease onset than patients who did not require colectomy. Combining these results with gene expression profiles, we identify CpG sites whose methylation patterns are most consistent with a contribution to poor disease outcomes and could thus be potential therapeutic targets.

CONCLUSIONS

Cell-specific epigenetic changes in the rectal mucosa in UC are associated with disease severity and outcome. Current therapeutics may more effectively target the immune than the epithelial and fibroblast compartments.

Paediatric Inflammatory Bowel Disease: A Multi-Stakeholder Perspective to Improve Development of Drugs for Children and Adolescents

BACKGROUND AND AIMS

Despite recent approvals for new drugs to treat adults with Crohn's disease or ulcerative colitis, there are only two approved advanced treatment options [infliximab and adalimumab] for children with inflammatory bowel disease [IBD]. There are many potential new therapies being developed for adult and paediatric IBD. Moreover, regulatory agencies in both the European Union and USA have processes in place to support the early planning and initiation of paediatric studies. Nevertheless, unacceptable delays in approvals for use of drugs in children persist, with an average 7-year gap, or longer, between authorization of new IBD drugs for adults and children.

METHODS

A 2-day virtual meeting was held during April 14-15, 2021 for multi-stakeholders [clinical academics, patient community, pharmaceutical companies and regulators] to discuss their perspectives on paediatric drug development for IBD.

RESULTS

The multi-stakeholder group presented, discussed and proposed actions to achieve expediting the approval of new drugs in development for paediatric IBD.

CONCLUSIONS

Collaborative action points for all stakeholders are required to make progress and facilitate new drug development for children with IBD.

Real world population pharmacokinetic study in children and young adults with inflammatory bowel disease discovers novel blood and stool microbial predictors of vedolizumab clearance

BACKGROUND

Vedolizumab for inflammatory bowel disease (IBD) is often intensified based on distinct pharmacokinetics in children. Prior adult-specific population pharmacokinetic models have identified limited covariates of drug clearance.

AIMS

To establish a population pharmacokinetic model for children and young adults to identify novel covariates of drug clearance to better account for paediatric-specific inter-patient variability in vedolizumab pharmacokinetics; a key secondary exploratory aim was to identify microbial signatures of pharmacokinetic outcomes in a subset of patients.

METHODS

The study included data from 463 observed vedolizumab concentrations (59 peaks and 404 troughs) from 74 patients with IBD (52 with Crohn's disease and 22 with ulcerative colitis or unclassified IBD, median age 16 years). Pharmacokinetic analysis was conducted with non-linear mixed effects modelling. For the evaluation of the exposure-response relationship, clinical outcomes were evaluated by trough levels, clearance and vedolizumab exposure. Whole-genome metagenomic sequencing was conducted at baseline and week 2.

RESULTS

A two-compartment population pharmacokinetic model was identified with a clear correlation between CL and weight, erythrocyte sedimentation rate, and hypoalbuminemia. Trough concentrations before infusion 3 (37 μg/ml) and before infusion 4 (20 μg/ml) best predicted steroid-free clinical remission at infusion 4. Using faecal metagenomics, we identified an early (baseline and week 2) abundance of butyrate-producing species and pathways that were associated with an infusion 4 trough concentration >20 μg/ml.

CONCLUSIONS

This novel paediatric vedolizumab pharmacokinetic model could inform precision dosing. While additional studies are needed, an abundance of faecal butyrate producers is associated with early response to vedolizumab, suggesting that microbial analysis may be beneficial to biological selection.

GATA6-AS1 regulates intestinal epithelial mitochondrial functions, and its reduced expression is linked to intestinal inflammation and less favorable disease course in ulcerative colitis (UC)

BACKGROUND AND AIMS

Widespread dysregulation of long non-coding RNAs (lncRNAs) including a reduction in GATA6-AS1 was noted in inflammatory bowel disease (IBD). We previously reported a prominent inhibition of epithelial mitochondrial functions in UC. However, the connection between reduction of GATA6-AS1 expression and attenuated epithelial mitochondrial functions was not yet defined.

METHODS

Mucosal transcriptomics was used to conform GATA6-AS1 reduction in several treatment naïve independent human cohorts (n=673). RNA pull-down followed by mass-spectrometry was used to determine GATA6-AS1 interactome. Metabolomics and mitochondrial respiration following GATA6-AS1 silencing in Caco-2, were used to elaborate on GATA6-AS1 functions.

RESULTS

GATA6-AS1 showed predominant expression in gut epithelia using single cell datasets. GATA6-AS1 levels were reduced in Crohn disease (CD) ileum and in ulcerative colitis (UC) rectum in independent cohorts. Reduced GATA6-AS1 lncRNA was further linked to more severe UC form, and to less favorable UC course. GATA6-AS1 interactome showed robust enrichment for mitochondrial proteins, and included TGM2, an autoantigen in celiac disease that is induced in UC, CD, and celiac, in contrast GATA6-AS1 reduction in these cohorts. GATA6-AS1 silencing resulted in induction of TGM2, and this was coupled with reduction in mitochondrial membrane potential and mitochondrial respiration, as well as in reduction of metabolites linked with aerobic respiration relevant to mucosal inflammation. TGM2 knockdown in GATA6-AS1 deficient cells rescued mitochondrial respiration.

CONCLUSIONS

GATA6-AS1 levels are reduced in UC, CD, and celiac, and in more severe UC forms. We highlight GATA6-AS1 as a target regulating epithelial mitochondrial functions, potentially through controlling TGM2 levels.

Multicenter Cohort Study of Infliximab Pharmacokinetics and Therapy Response in Pediatric Acute Severe Ulcerative Colitis

BACKGROUND & AIMS

We aimed to model infliximab (IFX) pharmacokinetics (PK) in pediatric acute severe ulcerative colitis (ASUC) and assess the association between PK parameters, including drug exposure, and clinical response.

METHODS

We studied a multicenter prospective cohort of hospitalized children initiating IFX for ASUC or IBD-unclassified. Serial IFX serum concentrations over 26 weeks were used to develop a PK model. We tested the association of PK parameter estimates with day 7 clinical response, week 8 clinical remission, week 26 corticosteroid-free clinical remission (CSF-CR) (using the Pediatric Ulcerative Colitis Activity Index), and colectomy-free survival.

RESULTS

Thirty-eight participants received IFX (median initial dose, 9.9 mg/kg). Day 7 clinical response, week 8 clinical remission, and week 26 CSF-CR occurred in 71%, 55%, and 43%, respectively. Albumin, C-reactive protein, white blood cell count, platelets, weight, and antibodies to IFX were significant covariates incorporated into a PK model. Week 26 non-remitters exhibited faster IFX clearance than remitters (P = .013). However, cumulative IFX exposure did not differ between clinical response groups. One (2.7%) and 4 (10.8%) participants underwent colectomy by week 26 and 2 years, respectively. Day 3 IFX clearance >0.02 L/h was associated with colectomy (hazard ratio, 58.2; 95% confidence interval, 6.0-568.6; P < .001).

CONCLUSIONS

At median higher-than-label IFX dosing for pediatric ASUC, baseline faster IFX CL was associated with colectomy and at week 26 with lack of CSF-CR. IFX exposure was not predictive of clinical outcomes. Higher IFX dosing may sufficiently optimize early outcomes in pediatric ASUC. Larger studies are warranted to determine whether sustained intensification can overcome rapid clearance and improve later outcomes.

CLINICALTRIALS

gov identifier: NCT02799615.

Follicular Dendritic Cell Sarcoma in a Patient With Adolescent-Onset Crohn's Disease Exposed to Multiple Immunomodulator and Biologic Therapies

Children and adolescents with inflammatory bowel disease are often treated with immunomodulators (thiopurines, methotrexate) and biologics (anti-TNF, anti-integrin) for extended periods despite concerns about long-term safety. Here, we report a case of follicular dendritic cell sarcoma, a very rare malignancy, and the first reported presentation in a patient with inflammatory bowel disease exposed to infliximab, methotrexate, and vedolizumab. We review the key clinical features and diagnostic factors of this malignancy. The pathogenesis of follicular dendritic cell sarcoma is largely unknown, however, knock out of B-cell TNF in mice has been related to follicular dendritic cell dysregulation through its impact on NF-κB pathways and CXCL13 chemokines. It is unknown whether any relationship exists between this patient's diagnosis of Crohn's disease and therapeutic exposures to this rare malignancy. We document this case in the literature to raise awareness among other clinicians who may observe a similar case.

Barriers From Third-Party Payers to Biologic Use in Pediatric Inflammatory Bowel Disease

Biologic agents are now standard of care in the treatment of inflammatory bowel disease (IBD). The ability to use biologics in clinical practice is in part dictated by insurance company policies. There is a long delay between adult and pediatric approval of biologic agents, and these therapies are often denied by third-party payers for use in pediatric IBD patients. This study prospectively identified pediatric patients with IBD who were started on a biologic medication at our institution, and third-party payer decisions were recorded. There were no denials in patients with Medicaid, but private payers frequently interfered with use of biologic agents. Reasons for denial are generally for use of a specific off-label agent or dosing of an approved agent. These denials lead to delayed treatment, nonmedically sound changes in therapy, and increased administrative burden on providers.

Antibody Responses to SARS-CoV-2 After Infection or Vaccination in Children and Young Adults With Inflammatory Bowel Disease

BACKGROUND

Characterization of neutralization antibodies to SARS-CoV-2 infection or vaccination in children and young adults with inflammatory bowel disease (IBD) receiving biologic therapies is crucial.

METHODS

We performed a prospective longitudinal cohort study evaluating SARS-CoV-2 spike protein receptor binding domain (S-RBD) IgG positivity along with consistent clinical symptoms in patients with IBD receiving infliximab or vedolizumab. Serum was also obtained following immunization with approved vaccines. The IgG antibody to the spike protein binding domain of SARS-CoV-2 was assayed with a fluorescent bead-based immunoassay that takes advantage of the high dynamic range of fluorescent molecules using flow cytometry. A sensitive and high-throughput neutralization assay that incorporates SARS-CoV-2 spike protein onto a lentivirus and measures pseudoviral entry into ACE2-angiotensin converting enzyme 2 (ACE2) expressing human embryonic kidney 293 (HEK-293) cells was used.

RESULTS

There were 436 patients enrolled (mean age, 17 years, range 2-26 years; 58% male; 71% Crohn's disease, 29% ulcerative colitis, IBD-unspecified). Forty-four (10%) of enrolled subjects had SARS-CoV-2 S-RBD IgG antibodies. Compared to non-IBD adults (ambulatory) and hospitalized pediatric patients with PCR documented SARS-CoV-2 infection, S-RBD IgG antibody levels were significantly lower in the IBD cohort and by 6 months post infection most patients lacked neutralizing antibody. Following vaccination (n = 33), patients had a 15-fold higher S-RBD antibody response in comparison with natural infection, and all developed neutralizing antibodies to both wild type and variant SARS-CoV-2.

CONCLUSIONS

The lower and less durable SARS-CoV-2 S-RBD IgG response to natural infection in IBD patients receiving biologics puts them at risk of reinfection. The robust response to immunization is likely protective.

Targeted Assessment of Mucosal Immune Gene Expression Predicts Clinical Outcomes in Children with Ulcerative Colitis

BACKGROUND AND AIMS

We aimed to determine whether a targeted gene expression panel could predict clinical outcomes in paediatric ulcerative colitis [UC] and investigated putative pathogenic roles of predictive genes.

METHODS

In total, 313 rectal RNA samples from a cohort of newly diagnosed paediatric UC patients (PROTECT) were analysed by a real-time PCR microfluidic array for expression of type 1, 2 and 17 inflammation genes. Associations between expression and clinical outcomes were assessed by logistic regression. Identified prognostic markers were further analysed using existing RNA sequencing (RNA-seq) data sets and tissue immunostaining.

RESULTS

IL13RA2 was associated with a lower likelihood of corticosteroid-free remission (CSFR) on mesalamine at week 52 (p = .002). A model including IL13RA2 and only baseline clinical parameters was as accurate as an established clinical model, which requires week 4 remission status. RORC was associated with a lower likelihood of colectomy by week 52. A model including RORC and PUCAI predicted colectomy by 52 weeks (area under the receiver operating characteristic curve 0.71). Bulk RNA-seq identified IL13RA2 and RORC as hub genes within UC outcome-associated expression networks related to extracellular matrix and innate immune response, and lipid metabolism and microvillus assembly, respectively. Adult UC single-cell RNA-seq data revealed IL13RA2 and RORC co-expressed genes were localized to inflammatory fibroblasts and undifferentiated epithelial cells, respectively, which was supported by protein immunostaining.

CONCLUSION

Targeted assessment of rectal mucosal immune gene expression predicts 52-week CSFR in treatment-naïve paediatric UC patients. Further exploration of IL-13Rɑ2 as a therapeutic target in UC and future studies of the epithelial-specific role of RORC in UC pathogenesis are warranted.

Simplified Magnetic Resonance Index of Activity Is Useful for Terminal Ileal but not Colonic Disease in Pediatric Crohn Disease

BACKGROUND

Ileocolonoscopy (IC) detects mucosal inflammation and magnetic resonance enterography (MRE) detects transmural inflammation in Crohn disease (CD). We aimed to evaluate the relationship between the simplified magnetic resonance index of activity (MARIAs) and measures of inflammation by IC in children with newly diagnosed CD.

METHODS

Retrospective review of 140 patients 6-18 years of age with CD who had baseline IC and MRE within 5 weeks of diagnosis. MARIAs was calculated for each intestinal segment (terminal ileum [TI], ascending colon, transverse colon, descending colon, sigmoid colon, rectum), defined as (1 × thickness > 3 mm) + (1 × edema) + (1 × fat stranding) + (2 × ulcers). Sensitivity and specificity were derived using receiver operating characteristic (ROC) curves to compare MARIAs to IC findings.

RESULTS

Using IC as the reference standard, the cutoff MARIAs ≥1 identified TI segments with active inflammation with 84% sensitivity, 73% specificity, 85% positive predictive value (PPV), 70% negative predictive value (NPV), and area under the curve (AUC) 0.782 (95% confidence interval [CI] 0.689-0.876). The cutoff MARIAs ≥2 identified TI segments with severe lesions with 87% sensitivity, 76% specificity, 87% PPV, 76% NPV, and AUC 0.814 (95% CI 0.712-0.916). There was poor sensitivity for all colonic segments.

CONCLUSION

The MARIAs is feasible and accurate in reflecting disease activity in the TI, but not in the colon, in children with newly diagnosed CD. Although the MARIAs may be useful for monitoring TI disease activity over time, full assessment continues to require both IC and MRE.

Methylation quantitative trait loci are largely consistent across disease states in Crohn’s disease

Recently, we identified 1,189 CpG sites whose DNA methylation level in blood associated with Crohn’s disease. Here, we examined associations between DNA methylation and genetic variants to identify methylation quantitative trait loci across disease states in (1) 402 blood samples from 164 newly diagnosed pediatric Crohn’s disease patients taken at 2 time points (diagnosis and follow-up), and 74 non-inflammatory bowel disease controls, (2) 780 blood samples from a non-Crohn’s disease adult population, and (3) 40 ileal biopsies (17 Crohn’s disease cases and 23 non-inflammatory bowel disease controls) from group (1). Genome-wide DNAm profiling and genotyping were performed using the Illumina MethylationEPIC and Illumina Multi-Ethnic arrays. SNP-CpG associations were identified via linear models adjusted for age, sex, disease status, disease subtype, estimated cell proportions, and genotype-based principal components. In total, we observed 535,448 SNP-CpG associations between 287,881 SNPs and 12,843 CpG sites (P &lt; 8.21 × 10−14). Associations were highly consistent across different ages, races, disease states, and tissue types, suggesting that the majority of these methylation quantitative trait loci participate in common gene regulation. However, genes near CpGs associated with inflammatory bowel disease SNPs were enriched for 18 KEGG pathways relevant to inflammatory bowel disease-linked immune function and inflammatory responses. We observed suggestive evidence for a small number of tissue-specific associations and disease-specific associations in ileum, though larger studies will be needed to confirm these results. Our study concludes that the vast majority of blood-derived methylation quantitative trait loci are common across individuals, though a subset may be involved in processes related to Crohn’s disease. Independent cohort studies will be required to validate these findings.

Identification of a Pain-Specific Gene Expression Profile for Pediatric Recurrent Abdominal Pain

Objectives: Functional Abdominal Pain (FAP) and Irritable Bowel Syndrome (IBS) are common recurrent abdominal pain diagnoses with the hallmark, lack of inflammation. To identify a biological signature for IBS/FAP in the colon, this study used genetic profiling to uncover gene expression changes associated with IBS/FAP and abdominal pain. Methods: Patients (8 to 17 years) newly diagnosed with IBS or FAP were enrolled in the study. At diagnostic colonoscopy, three rectal biopsies were collected, and gene expression analysis was performed using a Qiagen PCR Array. Relative fold difference in gene expression for 84 pain-associated genes was calculated using the 2-ΔΔ Cq method compared with pain-free controls. Factors affecting pain burden (Pain Burden Interview; PBI) were analyzed, including age, sex, rectal inflammation, and gene expression. Data were analyzed using multiple stepwise linear regression and 2-tailed t tests (P ≤ 0.05). Results: Of the 22 total patients in the study, 19 were diagnosed with either IBS-Constipation (frequency of 5.26%), IBS-Diarrhea (47.37%), IBS-Mixed (10.53%), or FAP (36.84%). IBS/FAP patients reported significantly higher pain burden at the time of diagnosis compared to pain-free controls (p < 0.001), as well as significantly higher abdominal pain (p = 0.01). Of the 84 genes, expression of GRIN1 (p = 0.02), MAPK3 (p = 0.04), P2X4 (p = 0.04), and PTGES3 (p = 0.02) were all significantly associated with PBI score. Discussion: Abdominal pain associated with IBS/FAP in pediatric patients may be linked to the expression of GRIN1, MAPK3, P2X4, and PTGES3, pointing to potential novel therapeutic targets for management of recurring abdominal pain.

Pharmacokinetics, Safety and Efficacy of Intravenous Vedolizumab in Paediatric Patients with Ulcerative Colitis or Crohn's Disease: Results from the Phase 2 HUBBLE Study

BACKGROUND AND AIMS

To date, there are no systematic pharmacokinetic [PK] data on vedolizumab in paediatric inflammatory bowel disease [IBD]. We report results from HUBBLE, a dose-ranging, phase 2 trial evaluating the PK, safety and efficacy of intravenous vedolizumab for paediatric IBD.

METHODS

Enrolled patients [aged 2-17 years] with moderate to severe ulcerative colitis [UC] or Crohn's disease [CD] and body weight ≥10 kg were randomized by weight to receive low- or high-dose vedolizumab [≥30 kg, 150 or 300 mg; <30 kg, 100 or 200 mg] on Day 1 and Weeks 2, 6 and 14. Week 14 assessments included PK, clinical response and exposure-response relationship. Safety and immunogenicity were assessed.

RESULTS

Randomized patients weighing ≥30 kg [UC, n = 25; CD, n = 24] and <30 kg [UC, n = 19; CD, n = 21] had a baseline mean [standard deviation] age of 13.5 [2.5] and 7.6 [3.2] years, respectively. In almost all indication and weight groups, area under the concentration curve and average concentration increased ~2-fold from low to high dose; the trough concentration was higher in each high-dose arm compared with the low-dose arms. At Week 14, clinical response occurred in 40.0-69.2% of patients with UC and 33.3-63.6% with CD in both weight groups. Clinical responders with UC generally had higher trough concentration vs non-responders, while this trend was not observed in CD. Fourteen per cent [12/88] of patients had treatment-related adverse events and 6.8% [6/88] had anti-drug antibodies.

CONCLUSIONS

Vedolizumab exposure increased in an approximate dose-proportional manner. No clear dose-response relationship was observed in this limited cohort. No new safety signals were identified.

Antibodies-to-infliximab accelerate clearance while dose intensification reverses immunogenicity and recaptures clinical response in paediatric Crohn's disease

BACKGROUND

Antibodies to infliximab (ATI) are associated with secondary loss of response and increased risk for drug reactions. Limited studies have associated ATI with increased infliximab clearance.

AIMS

We assessed the impact of ATI on infliximab clearance and loss of response in an inception paediatric Crohn's disease cohort with 1-year follow-up.

METHODS

This multi-centre prospective cohort study collected peak and trough serum infliximab/ATI concentrations from 660 infusions (78 patients) during the first year of therapy. Clinicians were blinded to these research labs. The primary outcome was the difference in infliximab clearance between ATI-positive (ATI) and ATI-negative (no-ATI) patients. Secondary outcomes included pre-treatment predictors of ATI (including HLA-DQA1 genotyping). Clinical remission, loss of response and infliximab clearance were compared between pre-ATI, during ATI and following ATI resolution with MANOVA. Time to ATI was calculated by Cox proportional Hazards model.

RESULTS

ATI were detected in 68% (53/78) patients with a median concentration of 76 ng/mL (range 23-1828). Maximum ATI concentration was <200 ng/mL in 73.6% (39/53). Median clearance in ATI patients was higher (with higher clearance if loss of response), compared to no-ATI patients (P < 0.001). Neutrophil CD64 ratio >6 and starting dose <7.5 mg/kg independently predicted ATI in multivariable regression, while HLA-DQA1*05 presence did not. Dose adjustment resolved ATI in 37.5% (12/32) patients with concomitant infliximab concentration and clearance recovery. A maximum ATI level of ≤99 ng/mL predicted ATI resolution (area under the receiver operating curve 0.80 [95% CI 0.64-0.96]).

CONCLUSIONS

In this real-world cohort, ATI as low as 23 ng/mL impacted drug clearance. Our data suggest that dose optimisation for low-level ATI can improve infliximab clearance and prevent loss of response.

Stratification of risk of progression to colectomy in ulcerative colitis via measured and predicted gene expression

An important goal of clinical genomics is to be able to estimate the risk of adverse disease outcomes. Between 5% and 10% of individuals with ulcerative colitis (UC) require colectomy within 5 years of diagnosis, but polygenic risk scores (PRSs) utilizing findings from genome-wide association studies (GWASs) are unable to provide meaningful prediction of this adverse status. By contrast, in Crohn disease, gene expression profiling of GWAS-significant genes does provide some stratification of risk of progression to complicated disease in the form of a transcriptional risk score (TRS). Here, we demonstrate that a measured TRS based on bulk rectal gene expression in the PROTECT inception cohort study has a positive predictive value approaching 50% for colectomy. Single-cell profiling demonstrates that the genes are active in multiple diverse cell types from both the epithelial and immune compartments. Expression quantitative trait locus (QTL) analysis identifies genes with differential effects at baseline and week 52 follow-up, but for the most part, differential expression associated with colectomy risk is independent of local genetic regulation. Nevertheless, a predicted polygenic transcriptional risk score (PPTRS) derived by summation of transcriptome-wide association study (TWAS) effects identifies UC-affected individuals at 5-fold elevated risk of colectomy with data from the UK Biobank population cohort studies, independently replicated in an NIDDK-IBDGC dataset. Prediction of gene expression from relatively small transcriptome datasets can thus be used in conjunction with TWASs for stratification of risk of disease complications.

Characterizing clinical features and location-specific gene expression profiles associated with pain burden in children with functional dyspepsia

BACKGROUND

In children with functional dyspepsia (FD), genes involved in pain modulation may be differentially expressed contributing to chronic pain.

METHODS

Children with suspected FD (cases) and known eosinophilic esophagitis (controls) undergoing esophagogastroduodenoscopy completed the Rome IV Diagnostic, Pain Burden and Frequency Severity-Duration questionnaires. Two antral and two duodenal biopsies were collected and relative fold differences in gene expression for 84 pain-associated genes compared to pain-free controls were calculated.

RESULTS

Sixty-six subjects with FD (postprandial distress syndrome = 34, epigastric pain syndrome = 7, both = 25; 65% female; mean age 13.7 years) and 13 pain-free controls (8% female; mean age 12.7) were studied. There were no significant differences in antral and duodenal eosinophilic counts or distribution between the pain and pain-free groups. Pain severity and burden did not differ significantly between FD subgroups and neither measure significantly correlated with eosinophil counts in the antrum or duodenum. Analysis of 47 antral and 39 duodenal biospecimens revealed 5 candidate genes significantly associated with pain burden: antral EDN1, PTGES3 and duodenal HTR1A, P2Y1, SCN3A (p < 0.01). Subsequent stringent statistical analysis comparing those with significant pain versus no pain revealed antral PTGES3 and duodenal SCN3A were the highest priority candidate genes (p < 0.001).

CONCLUSIONS

Pain burden in pediatric FD may be linked to antral EDN1, PTGES3 and duodenal HTR1A, P2Y1, SCN3A differential expression. These genes are known to be involved in pain conduction, modulation, and neurotransmission, suggesting potential therapeutic targets for managing pain in FD.

Assessing disease activity using the pediatric Crohn’s disease activity index: Can we use subjective or objective parameters alone?

BACKGROUND

The pediatric Crohn’s disease activity index (PCDAI) is used as a standard tool to assess disease activity in clinical trials for pediatric Crohn’s disease.

AIM

To examine which items on the PCDAI drive assessment of disease activity, and how subgroups of subjective and objective items reflect change in disease state over time.

METHODS

Selective raw data from three prospectively collected datasets were combined, including 703 children with full PCDAI data at baseline, at 3-mo (Q1, n = 670), and 1-year (Q4, n = 474). Change in individual PCDAI scores from baseline to Q1 and to Q4 were examined using the non-weighted PCDAI.

RESULTS

Abdominal pain, well-being, weight, and stooling had the highest change scores over time. Objective indicators including albumin, abdominal exam, and height velocity followed. Change scores for well-being and abdominal exam did not explain significant variance at Q1 but were significant predictors at Q4 (P < 0.001 and P < 0.05). Subjective and objective subgroups of items predicted less variance (18% and 22%) on total PCDAI scores at Q1 and Q4 compared to the full PCDAI, or a composite scale (both 32%) containing significant predictors.

CONCLUSION

Although subjective items on the PCDAI change the most over time, the full PCDAI or a smaller composite of items including a combination of subjective and objective components classifies disease activity better than a subgroup of either subjective or objective items alone. Reliance on subjective or objective items as stand-alone proxies for disease activity measurement could result in misclassification of disease state.

Profiling non-coding RNA levels with clinical classifiers in pediatric Crohn's disease

BACKGROUND

Crohn's disease (CD) is a heritable chronic inflammatory disorder. Non-coding RNAs (ncRNAs) play an important role in epigenetic regulation by affecting gene expression, but can also directly affect protein function, thus having a substantial impact on biological processes. We investigated whether non-coding RNAs (ncRNA) at diagnosis are dysregulated during CD at different CD locations and future disease behaviors to determine if ncRNA signatures can serve as an index to outcomes.

METHODS

Using subjects belonging to the RISK cohort, we analyzed ncRNA from the ileal biopsies of 345 CD and 71 non-IBD controls, and ncRNA from rectal biopsies of 329 CD and 61 non-IBD controls. Sequence alignment was done (STAR package) using Human Genome version 38 (hg38) as reference panel. The differential expression (DE) analysis was performed with EdgeR package and DE ncRNAs were identified with a threshold of fold change (FC) > 2 and FDR < 0.05 after multiple test corrections.

RESULTS

In total, we identified 130 CD specific DE ncRNAs (89 in ileum and 41 in rectum) when compared to non-IBD controls. Similarly, 35 DE ncRNAs were identified between B1 and B2 in ileum, whereas no differences among CD disease behaviors were noticed in rectum. We also found inflammation specific ncRNAs between inflamed and non-inflamed groups in ileal biopsies. Overall, we observed that expression of mir1244-2, mir1244-3, mir1244-4, and RN7SL2 were increased during CD, regardless of disease behavior, location, or inflammatory status. Lastly, we tested ncRNA expression at baseline as potential tool to predict the disease status, disease behaviors and disease inflammation at 3-year follow up.

CONCLUSIONS

We have identified ncRNAs that are specific to disease location, disease behavior, and disease inflammation in CD. Both ileal and rectal specific ncRNA are changing over the course of CD, specifically during the disease progression in the intestinal mucosa. Collectively, our findings show changes in ncRNA during CD and may have a clinical utility in early identification and characterization of disease progression.

Vedolizumab Experience in Children and Adolescents With Inflammatory Bowel Disease: A Multicenter Observational Study

Background

Vedolizumab is increasingly used off-label to treat children and adolescents with inflammatory bowel disease (IBD). In the absence of rigorous clinical trial experience, multicenter observational data are important to establish expectations for efficacy and safety. We examined 1-year outcomes following vedolizumab therapy in a large multicenter pediatric IBD cohort.

Methods

We performed a retrospective study of 159 pediatric patients (4-17 years old) with IBD [78, Crohn disease (CD); 81, ulcerative colitis/IBD-unspecified (UC/IBD-U)] treated with vedolizumab for 1 year at 8 pediatric medical centers in the United States. Demographics, clinical outcomes, laboratory data, and vedolizumab dosing were recorded. The primary outcome was corticosteroid (CS)-free clinical remission at 1 year. Other measured outcomes were clinical remission at 12 and/or 24 weeks, laboratory outcomes at 1 year, and endoscopy/histology results at 1 year.

Results

Among the 159 patients (mean age, 14.5 ± 2.4 years; 86% anti-TNF experienced), 68/159 (43%) achieved CS-free clinical remission at 1 year (CD, 35/78, 45%; UC/IBD-U, 33/81, 40%). Vedolizumab therapy failed and was discontinued in 33/159 (21%) patients prior to 1 year (CD, 18/78, 23%; UC/IBD-U, 15/81, 19%). While week 12 clinical remission was not predictive of 1-year clinical remission in either CD or UC/IBD-U, week 24 clinical remission was predictive of 1-year clinical remission only in CD patients. No infusion reactions or serious side effects were noted.

Conclusions

Vedolizumab was safe and effective in this pediatric population with approximately 43% achieving CS-free clinical remission at 1 year. Similar efficacy was noted in both CD and UC.

Antibody Responses to SARS-CoV-2 after Infection or Vaccination in Children and Young Adults with Inflammatory Bowel Disease

Background

Characterization of neutralization antibodies to SARS-CoV-2 infection or vaccination in children and young adults with inflammatory bowel disease (IBD) receiving biologic therapies is crucial.

Methods

W e performed a prospective longitudinal cohort study evaluating SARS-CoV-2 Spike protein receptor binding domain (S-RBD) IgG positivity along with consistent clinical symptoms in patients with IBD receiving infliximab or vedolizumab. Serum was also obtained following immunization with approved vaccines. IgG antibody to the spike protein binding domain of SARS-CoV-2 was assayed with a fluorescent bead-based immunoassay that takes advantage of the high dynamic range of fluorescent molecules using flow cytometry. A sensitive and high-throughput neutralization assay that incorporates SARS-CoV-2 Spike protein onto a lentivirus and measures pseudoviral entry into ACE2 expressing HEK-293 cells was used.

Results

436 patients were enrolled (mean age 17 years, range 2-26 years, 58% male, 71% Crohn’s disease, 29% ulcerative colitis, IBD-unspecified). 44 (10%) of enrolled subjects had SARS-CoV-2 S-RBD IgG antibodies. Compared to non-IBD adults (ambulatory) and hospitalized pediatric patients with PCR documented SARS-CoV-2 infection, S-RBD IgG antibody levels were significantly lower in the IBD cohort and by 6 months post infection most patients lacked neutralizing antibody. Following vaccination (n=33) patients had a 15-fold higher S-RBD antibody response in comparison to natural infection, and all developed neutralizing antibodies to both wild type and variant SARS-CoV-2.

Conclusions and Relevance

The lower and less durable SARS-CoV-2 S-RBD IgG response to natural infection in IBD patients receiving biologics puts them at risk of reinfection. The robust response to immunization is likely protective.

Summary

Our study showed a low and poorly durable SARS-CoV-2 S-RBD neutralizing IgG response to natural infection in IBD patients receiving biologics potentially putting them at risk of reinfection. However, they also had a robust response to immunization that is likely protective.

Ustekinumab in Paediatric Patients with Moderately to Severely Active Crohn's Disease: Pharmacokinetics, Safety, and Efficacy Results from UniStar, a Phase 1 Study

BACKGROUND AND AIMS

The objective was to evaluate the pharmacokinetics, safety/tolerability, and efficacy of ustekinumab in children with moderately to severely active Crohn's disease.

METHODS

In this Phase 1, multicentre, 16-week, double-blind, induction dose-ranging study [NCT02968108], patients aged 2-<18 years [body weight ≥10 kg] were randomised [1:1] to one of two weight range-based intravenous induction doses: 130 mg vs 390 mg in patients ≥40kg and 3 mg/kg vs 9 mg/kg in patients <40kg. At Week 8, all patients received a single subcutaneous ustekinumab maintenance dose of 90 mg in patients ≥40kg or 2 mg/kg in patients <40kg.

RESULTS

A total of 44 patients were randomised and treated with ustekinumab [n = 23 lower dose; n = 21 higher dose]; median [interquartile range] age was 13.0 [12-16] years. Pharmacokinetics were similar to those in adults with Crohn's disease. However, serum ustekinumab concentrations were lower among those with body weight <40 kg compared with patients ≥40 kg and the reference Phase 3 adult population. Through Week 16, 73% of patients reported ≥1 adverse event [82.6% lower vs 62% higher dose]; two discontinued due to adverse events [one in each group]. Serious adverse events occurred in 16% [26% lower, 5% higher dose], with Crohn's disease exacerbation being the most frequent. At Week 16, 22%/29% [lower/higher dose] achieved clinical remission [Paediatric Crohn's Disease Activity Index ≤10].

CONCLUSIONS

The pharmacokinetics/safety profiles were generally consistent with those observed in adults with Crohn's disease. These results suggest a different dosing regimen may be required for patients <40 kg from that employed in this study; additional pharmacokinetic analyses may be needed in this population.

Clinical and Host Biological Factors Predict Colectomy Risk in Children Newly Diagnosed With Ulcerative Colitis

BACKGROUND

Develop a clinical and biological predictive model for colectomy risk in children newly diagnosed with ulcerative colitis (UC).

METHODS

This was a multicenter inception cohort study of children (ages 4-17 years) newly diagnosed with UC treated with standardized initial regimens of mesalamine or corticosteroids (CS) depending upon initial disease severity. Therapy escalation to immunomodulators or infliximab was based on predetermined criteria. Patients were phenotyped by clinical activity per the Pediatric Ulcerative Colitis Activity Index (PUCAI), disease extent, endoscopic/histologic severity, and laboratory markers. In addition, RNA sequencing defined pretreatment rectal gene expression and high density DNA genotyping by the Affymetrix UK Biobank Axiom Array. Coprimary outcomes were colectomy over 3 years and time to colectomy. Generalized linear models, Cox proportional hazards multivariate regression modeling, and Kaplan-Meier plots were used.

RESULTS

Four hundred twenty-eight patients (mean age 13 years) started initial theapy with mesalamine (n = 136), oral CS (n = 144), or intravenous CS (n = 148). Twenty-five (6%) underwent colectomy at ≤1 year, 33 (9%) at ≤2 years, and 35 (13%) at ≤3 years. Further, 32/35 patients who had colectomy failed infliximab. An initial PUCAI ≥ 65 was highly associated with colectomy (P = 0.0001). A logistic regression model predicting colectomy using the PUCAI, hemoglobin, and erythrocyte sedimentation rate had a receiver operating characteristic area under the curve of 0.78 (95% confidence interval [0.73, 0.84]). Addition of a pretreatment rectal gene expression panel reflecting activation of the innate immune system and response to external stimuli and bacteria to the clinical model improved the receiver operating characteristic area under the curve to 0.87 (95% confidence interval [0.82, 0.91]).

CONCLUSIONS

A small group of children newly diagnosed with severe UC still require colectomy despite current therapies. Our gene signature observations suggest additional targets for management of those patients not responding to current medical therapies.

Colonic Epithelial-Derived Selenoprotein P Is the Source for Antioxidant-Mediated Protection in Colitis-Associated Cancer

BACKGROUND & AIMS

Patients with inflammatory bowel disease (IBD) demonstrate nutritional selenium deficiencies and are at greater risk of developing colon cancer. Previously, we determined that global reduction of the secreted antioxidant selenium-containing protein, selenoprotein P (SELENOP), substantially increased tumor development in an experimental colitis-associated cancer (CAC) model. We next sought to delineate tissue-specific contributions of SELENOP to intestinal inflammatory carcinogenesis and define clinical context.

METHODS

Selenop floxed mice crossed with Cre driver lines to delete Selenop from the liver, myeloid lineages, or intestinal epithelium were placed on an azoxymethane/dextran sodium sulfate experimental CAC protocol. SELENOP loss was assessed in human ulcerative colitis (UC) organoids, and expression was queried in human and adult UC samples.

RESULTS

Although large sources of SELENOP, both liver- and myeloid-specific Selenop deletion failed to modify azoxymethane/dextran sodium sulfate-mediated tumorigenesis. Instead, epithelial-specific deletion increased CAC tumorigenesis, likely due to elevated oxidative stress with a resulting increase in genomic instability and augmented tumor initiation. SELENOP was down-regulated in UC colon biopsies and levels were inversely correlated with endoscopic disease severity and tissue S100A8 (calprotectin) gene expression.

CONCLUSIONS

Although global selenium status is typically assessed by measuring liver-derived plasma SELENOP levels, our results indicate that the peripheral SELENOP pool is dispensable for CAC. Colonic epithelial SELENOP is the main contributor to local antioxidant capabilities. Thus, colonic SELENOP is the most informative means to assess selenium levels and activity in IBD patients and may serve as a novel biomarker for UC disease severity and identify patients most predisposed to CAC development.

Whole-genome sequencing of African Americans implicates differential genetic architecture in inflammatory bowel disease

Whether or not populations diverge with respect to the genetic contribution to risk of specific complex diseases is relevant to understanding the evolution of susceptibility and origins of health disparities. Here, we describe a large-scale whole-genome sequencing study of inflammatory bowel disease encompassing 1,774 affected individuals and 1,644 healthy control Americans with African ancestry (African Americans). Although no new loci for inflammatory bowel disease are discovered at genome-wide significance levels, we identify numerous instances of differential effect sizes in combination with divergent allele frequencies. For example, the major effect at PTGER4 fine maps to a single credible interval of 22 SNPs corresponding to one of four independent associations at the locus in European ancestry individuals but with an elevated odds ratio for Crohn disease in African Americans. A rare variant aggregate analysis implicates Ca²⁺-binding neuro-immunomodulator CALB2 in ulcerative colitis. Highly significant overall overlap of common variant risk for inflammatory bowel disease susceptibility between individuals with African and European ancestries was observed, with 41 of 241 previously known lead variants replicated and overall correlations in effect sizes of 0.68 for combined inflammatory bowel disease. Nevertheless, subtle differences influence the performance of polygenic risk scores, and we show that ancestry-appropriate weights significantly improve polygenic prediction in the highest percentiles of risk. The median amount of variance explained per locus remains the same in African and European cohorts, providing evidence for compensation of effect sizes as allele frequencies diverge, as expected under a highly polygenic model of disease.

Achieving Target Infliximab Drug Concentrations Improves Blood and Fecal Neutrophil Biomarkers in Crohn's Disease

BACKGROUND

The neutrophil fecal biomarkers, calprotectin (FCP) and lactoferrin (LCT), and peripheral blood neutrophil CD64 surface receptor (nCD64) are biomarkers for mucosal inflammation in inflammatory bowel disease (IBD). Although FCP has been evaluated as a biomarker for mucosal healing, cut points for LCT and nCD64 are less known. We aimed to identify the cut points for LCT and nCD64 that were associated with FCP remission, with a secondary aim to evaluate the relationship between biochemical outcomes and infliximab (IFX) trough concentrations.

METHODS

We analyzed FCP, LCT, and nCD64 before and after IFX induction in a pediatric Crohn's disease (CD) cohort study. Week-14 FCP biomarker remission was defined as FCP <250 µg/g, with clinical response defined as a weighted Pediatric Crohn's Disease Activity Index <12.5 or Δ>17.5 improvement. Predictive outcomes were calculated by receiver operating characteristics (ROCs).

RESULTS

Among 56 CD patients, ROC analysis identified an infusion 4 LCT <8.06 (area under the receiver operator characteristics [AUROC], 0.934, P < 0.001) and nCD64 <6.12 (AUROC, 0.76, P = 0.02) as the ideal cut points for week-14 FCP biomarker remission. End of induction IFX-trough of >9.4 µg/mL (AUROC, 0.799, P = 0.002) and >11.5 µg/mL (AUROC, 0.835, P = 0.003) were associated with a FCP <250 and FCP <100, respectively. We found patients achieving end of induction trough >5 µg/mL had a median FCP improvement (dose 1 to dose 4) of 90% compared with a median of 35% with levels <5 µg/mL (P = 0.024) with a similar median reduction in nCD64 (48% vs 20%, P = 0.031).

CONCLUSIONS

This study establishes cut points in neutrophil stool and blood biomarkers for both biochemical remission and therapeutic trough levels following induction therapy. Further studies that evaluate pharmacodynamic biomarker targets for endoscopic and histologic healing are warranted.

Mucosal Inflammatory and Wound Healing Gene Programs Reveal Targets for Stricturing Behavior in Pediatric Crohn's Disease

BACKGROUND AND AIMS

Ileal strictures are the major indication for resective surgery in Crohn's disease (CD). We aimed to define ileal gene programs present at diagnosis linked with future stricturing behavior during five year follow-up, and to identify potential small molecules to reverse these gene signatures.

METHODS

Antimicrobial serologies and pre-treatment ileal gene expression were assessed in a representative subset of 249 CD patients within the RISK multicenter pediatric CD inception cohort study, including 113 that are unique to this report. These data were used to define genes associated with stricturing behavior and for model testing to predict stricturing behavior. A bioinformatics approach to define small molecules which may reverse the stricturing gene signature was applied.

RESULTS

19 of the 249 patients developed isolated B2 stricturing behavior during follow-up, while 218 remained B1 inflammatory. Using deeper RNA sequencing than in our prior report, we have now defined an inflammatory gene signature including an oncostatin M co-expression signature, tightly associated with extra-cellular matrix (ECM) gene expression in those who developed stricturing complications. We further computationally prioritize small molecules targeting macrophage and fibroblast activation and angiogenesis which may reverse the stricturing gene signature. A model containing ASCA and CBir1 serologies and a refined eight ECM gene set was significantly associated with stricturing development by year five after diagnosis (AUC (95th CI) = 0.82 (0.7-0.94)).

CONCLUSION

An ileal gene program for macrophage and fibroblast activation is linked to stricturing complications in treatment naïve pediatric CD, and may inform novel small molecule therapeutic approaches.

Maintenance Golimumab Treatment in Pediatric UC Patients With Moderately to Severely Active UC: PURSUIT PEDS PK Long-Term Study Results

Background

Long-term safety, pharmacokinetics, and efficacy of open-label golimumab therapy in children with moderate-severe ulcerative colitis were evaluated.

Methods

Week-6 golimumab responders (Mayo score decrease of ≥30% and ≥3 points from baseline, rectal bleeding subscore of 0/1 or ≥1 decrease from baseline) entered the long-term extension at week 14 and received maintenance therapy (subcutaneous, q4w). Patients ≥45 kg could receive at-home treatments at week 18. Pharmacokinetic, safety, and efficacy results were summarized through week 126 (2 years).

Results

Among 35 enrolled children, 21 (60%) responded at week 6 and 20 entered the long-term extension (median age of 14.5 years and median weight of 46.1 kg). Eleven of 20 patients (55%) completed 2 years of treatment. No anaphylactic or serum sickness-like reactions, opportunistic infections, malignancies, tuberculosis, or deaths occurred. The safety profile of golimumab from weeks 14 through 126 and that observed through week 14 was generally consistent. Median trough golimumab concentrations in evaluable patients were consistent from weeks 14 (1.39, interquartile range 0.67-3.60) through 102 (1.18, 0.78-2.16), but higher at week 110 (4.10, 1.30-4.81). The incidence of antigolimumab antibodies increased from 10% (2/20) at week 30 to 25.0% (5/20) at week 126; 1 patient had neutralizing antibodies. At week 110, 50% (10/20) of patients were in remission (ie, Pediatric Ulcerative Colitis Activity Index <10). Among all enrolled patients, 28.6% (10/35) achieved remission at week 110.

Conclusions

Among children with ulcerative colitis who initially responded to golimumab induction and received q4w maintenance treatment in the long-term extension, 50% showed continued clinical benefit through 2 years. No new safety signals were observed.

Similar Long-Term Outcomes in Children Presenting With Abscess vs Phlegmon at Diagnosis of Crohn Disease

Background

Limited data are available for long-term outcomes of pediatric patients with abdominal abscess or phlegmon at diagnosis of Crohn disease.

Methods

We performed a retrospective chart review of such children over a recent 6-year period at 5 pediatric inflammatory bowel diseases.

Results

Fifty-two patients (mean age 15.9 ± 1.8 years) were reviewed. Thirty-six had an abscess and 27 (75%) required resectional therapy compared to 16 with phlegmon which 10 (63%) requiring surgery. Overall (37/52) 71% had surgery which was performed within 6 months in 32 (86%).

Conclusions

A similar high surgical rate exists whether pediatric patients with Crohn disease present with abscess or phlegmon.

Characterizing Clinical Features and Creating a Gene Expression Profile Associated With Pain Burden in Children With Inflammatory Bowel Disease

BACKGROUND

There is often dissociation between inflammatory activity and abdominal pain in children with inflammatory bowel disease (IBD), suggesting other factors may play a role in the pain experience.

METHODS

Patients (8 to 17 years) newly diagnosed with IBD were enrolled in the ALLAY Study: Assessing Risk Factors for Abdominal Pain in Children with Inflammatory Bowel Disease (NCT02984059). At diagnostic colonoscopy, 3 rectal biopsies were collected, and gene expression analysis was performed using Qiagen RT2 Profiler Neuropathic and Inflammatory Pain PCR Array. Relative fold difference in gene expression for 84 pain-associated genes was calculated using the 2-ΔΔ Cq method compared with pain-free controls. Factors affecting pain burden (Pain Burden Interview; PBI) were analyzed, including age, sex, rectal inflammation, and gene expression. Data were analyzed using multiple stepwise linear regression and 2-tailed t tests (P ≤ 0.05).

RESULTS

Thirty-nine newly diagnosed IBD patients were included (65% male, mean age 12.75 years [SD 2.63], 23 Crohn's disease, 16 ulcerative colitis), along with 3 controls. Mean PBI score was 7.73 (SD 6.4, range 0 to 23) for all patients. Age and sex were not predictive of pain burden, but disease activity score was (P = 0.03). Expression of TRPV3, OPRM1, P2X3, SCN9A, PTGS2, and MAPK14 were associated with PBI score. Subsequent 2-tailed t tests comparing patients with no pain (PBI score ≦ 2, N = 11) to those with pain (PBI > 2, N = 28) confirmed differential expression of TRPV3, PTGS2, and MAPK14 was in patients with pain (all P < 0.05).

CONCLUSION

Pain burden in newly diagnosed IBD patients may be linked to TRPV3, PTGS2, and MAPK14 expression, suggesting potential therapeutic targets for managing pain in IBD.

Cloning of ground-state intestinal stem cells from endoscopic biopsy samples

'Adult' or 'somatic' stem cells harbor an intrinsic ability to regenerate tissues. Heterogeneity of such stem cells along the gastrointestinal tract yields the known segmental specificity of this organ and may contribute to the pathology of certain enteric conditions. Here we detail technology for the generation of 'libraries' of clonogenic cells from 1-mm-diamter endoscopic biopsy samples from the human gastrointestinal tract. Each of the 150-300 independent clones in a typical stem cell library can be clonally expanded to billions of cells in a few weeks while maintaining genomic stability and the ability to undergo multipotent differentiation to the specific epithelia from which the sample originated. The key to this methodology is the intrinsic immortality of normal intestinal stem cells (ISCs) and culture systems that maintain them as highly immature, ground-state ISCs marked by a single-cell clonogenicity of 70% and a corresponding 250-fold proliferative advantage over spheroid technologies. Clonal approaches such as this enhance the resolution of molecular genetics, make genome editing easier, and may be useful in regenerative medicine, unravelling heterogeneity in disease, and facilitating drug discovery.

Health Care Cost for Children Newly Diagnosed With Inflammatory Bowel Disease

BACKGROUND

The increasing incidence of pediatric inflammatory bowel disease (IBD), along with more extensive and severe disease in children, raises concern for related health care expenditures.

AIM

The aim of this study was to quantify and characterize costs of pediatric IBD in the year following diagnosis.

METHODS

We identified all patients diagnosed with IBD at Connecticut Children's Medical Center in 2016 with a minimum of 1 year follow-up. Clinical and demographic factors were recorded at diagnosis. We examined paid service and professional costs related to outpatient medications and infusions, outpatient procedures and radiology imaging, inpatient services, and outpatient visits. Actual dollar reimbursements were from private and public payers. Data is reported as mean ± SD and median (IQR).

RESULTS

First-year cost data were collected on 67 patients (43 Crohn's disease [CD], 24 ulcerative colitis [UC], mean age 13 years [SD 3.22]) revealing a mean cost of $45,753 (SD $37,938), with $43,095 (SD $30,828) for CD and $50,516 (SD $48,557) for UC. Severe CD (n = 11) had a mean cost of $71,176 (SD $43,817) and severe UC (n = 5) $134,178 (SD $40,920). Patients receiving infusion therapy had a mean cost of $59,376 (SD $38,724) compared with $27,903 (SD $28,795) for those not receiving infusions. Overall cost distribution showed 37% from infusion costs, 25% hospital costs, 18% outpatient procedures, 10% outpatient oral medications, 7% outpatient imaging, and 3% outpatient visits.

CONCLUSIONS

Infusion therapy is a key driver of first-year costs for children newly diagnosed with IBD. Understanding cost distribution in relation to disease presentation can be helpful to anticipate future related costs.

Special considerations for biologic medications in pediatric ulcerative colitis

Introduction: More extensive disease, high rates of corticosteroid refractory and dependent disease, and the potential impact of disease on growth and development differentiate inflammatory bowel disease in children from adults. This is particularly evident in ulcerative colitis where pancolitis predominates, success of mesalamine alone in achieving remission is less than 50%, and there is a high need for immunomodulator or biologic therapies.Areas Covered: This review describes the use of infliximab, adalimumab, golimumab, and vedolizumab in the treatment of children with ulcerative colitis but is limited in scope due to the paucity of controlled clinical trials. A search of existing literature with keywords of these specific biological therapies as well as 'pediatric', 'ulcerative colitis,' and 'inflammatory bowel disease' was used to complete this review.Expert Opinion: Therapeutic drug monitoring has become standard of care when assessing dosing and changes in therapy and will play a role in future treatment planning.

Longitudinal non-adherence predicts treatment escalation in paediatric ulcerative colitis

BACKGROUND

Medication non-adherence in paediatric ulcerative colitis (UC) has been associated with negative health outcomes including flares in disease activity. However, no studies to date have examined longitudinal adherence to maintenance medication in a prospective controlled trial.

AIMS

To determine whether objectively measured adherence to standardised mesalazine (mesalamine) therapy over time was related to remission at 52 weeks and the need for treatment escalation in newly diagnosed paediatric patients with UC METHODS: PROTECT (NCT01536535) was a prospective, inception cohort, multi-site study of paediatric patients aged 4-17 years with newly diagnosed UC followed for 52 weeks. Patients received standardised mesalazine, with pre-established criteria for escalation to thiopurines or anti-TNFα inhibitors. Patients used pill bottles with electronic caps to monitor mesalazine adherence. We tested whether longitudinal adherence to mesalazine predicted steroid-free remission at week 52 (i.e. quiescent disease on mesalazine alone with no corticosteroids ≥4 weeks prior) and need for treatment escalation (i.e. introduction of immunomodulators, calcineurin-inhibitors or anti-TNFα inhibitors).

RESULTS

Among 268 patients, average mesalazine adherence trajectories did not predict week 52 steroid-free remission. Declining adherence over time strongly predicted treatment escalation (β = -.037, P = .001). By month 6, adherence rate ≤85.7% was associated with treatment escalation.

CONCLUSIONS

Non-adherence may have affected therapeutic efficacy of standardised mesalazine, thereby contributing to need for treatment escalation. Routine adherence monitoring for at least 6 months following treatment initiation and addressing adherence difficulties early in the disease course are recommended.

Characterization of Stool Virome in Children Newly Diagnosed With Moderate to Severe Ulcerative Colitis

BACKGROUND

Viral infections have been suggested as possible triggers for the onset of ulcerative colitis (UC).

METHODS

We employed VirCapSeq-Vert, a high-throughput sequencing virus capture platform, to examine the stool virome of children with newly diagnosed moderate to severe UC. We surveyed fecal samples collected at presentation, after symptom remission, and from a control group diagnosed with irritable bowel syndrome.

RESULTS

Seventy subjects with UC (mean age 13 years, 45 had moderate symptoms, 25 had severe, 69 of 70 had a Mayo endoscopy subscore 2/3) were studied. We detected a wide range of animal viruses that were taxonomically classified into 12 viral families. A virus was present in 50% of fecal samples collected at presentation, 41% of samples collected after remission, and 40% of samples in our control group. The most frequently identified viruses were diet-based gyroviruses. The UC cohort had a significantly higher prevalence of anelloviruses compared with the control cohort. However, we did not identify a single virus that can be implicated in the onset of UC and did not find an association between UC disease severity and viral presence.

CONCLUSION

Presence of virus in stool was not associated with the onset of pediatric UC.

Single-Cell Analysis of Crohn's Disease Lesions Identifies a Pathogenic Cellular Module Associated with Resistance to Anti-TNF Therapy

Clinical benefits of cytokine blockade in ileal Crohn's disease (iCD) are limited to a subset of patients. Here, we applied single-cell technologies to iCD lesions to address whether cellular heterogeneity contributes to treatment resistance. We found that a subset of patients expressed a unique cellular module in inflamed tissues that consisted of IgG plasma cells, inflammatory mononuclear phagocytes, activated T cells, and stromal cells, which we named the GIMATS module. Analysis of ligand-receptor interaction pairs identified a distinct network connectivity that likely drives the GIMATS module. Strikingly, the GIMATS module was also present in a subset of patients in four independent iCD cohorts (n = 441), and its presence at diagnosis correlated with failure to achieve durable corticosteroid-free remission upon anti-TNF therapy. These results emphasize the limitations of current diagnostic assays and the potential for single-cell mapping tools to identify novel biomarkers of treatment response and tailored therapeutic opportunities.

Unlimited expansion of intestinal stem cells from a wide range of ages

The recent technical advance in cloning and culturing ground-state intestinal stem cells (ISC) provides us an opportunity of accurate assessment of age-related impact on the function of highly proliferative intestinal stem cells. Our ability of indefinitely and robustly expanding single-stem-cell derived pedigrees in vitro allows us to study intestinal stem cells at the clonal level. Interestingly, comparable number of ISC clones was yielded from 1mm endoscopic biopsy of all donors despite the age. They were passaged in vitro as pedigrees and expanded to 1 billion cells in approximately sixty days without changes in stemness demonstrated by clonogenicity and multipotency. Therefore, our study shows that ISCs from a wide range of ages can be cloned and expanded to unlimited number in vitro with similar efficiency and stability. These patient-derived ISCs harbor intrinsic immortality and are ideal for autologous transplantation, supporting the promise of adult-stem-cell based personalized medicine.