Predictors of Long-term Clinical and Endoscopic Remission in Children With Crohn Disease Treated With Infliximab

Precise infliximab exposure and pharmacodynamic control to achieve deep remission in paediatric Crohn's disease (REMODEL-CD): study protocol for a multicentre, open-label, pragmatic clinical trial in the USA

INTRODUCTION

The only biologic therapy currently approved to treat moderate to severe Crohn's disease in children (<18 years old) are those that antagonise tumour necrosis factor-alpha (anti-TNF). Therefore, it is critically important to develop novel strategies that maximise treatment effectiveness in this population. There is growing evidence that rates of sustained corticosteroid-free clinical remission, endoscopic healing and drug durability considerably improve when patients receive early anti-TNF dose optimisations guided by reactive or proactive therapeutic drug monitoring and pharmacodynamic monitoring. In response, our team has developed a personalised and scalable infliximab dosing intervention that starts with dose selection and continues throughout maintenance to optimise drug exposure. We hypothesise that a precision dosing strategy starting from induction and targeting dose-specific pharmacokinetic and pharmacodynamic endpoints throughout therapy will significantly improve outcomes compared with a conventional dosing strategy.

METHODS AND ANALYSIS

Conduct a clinical trial to assess rates of deep remission between Crohn's disease patients receiving infliximab with precision dosing (n=90) versus conventional care (n=90). Patients (age 6-22 years) will be recruited from 10 medical centres in the USA. Each centre has been selected to provide either precision dosing or conventional care dosing. Precision dosing includes the use of a clinical decision support tool (RoadMAB) from the start of infliximab to achieve specific (personalised) trough concentrations and specific pharmacodynamic targets (at doses 3, 4 and 6). Conventional care includes the use of a modified infliximab starting dose (5 or 7.5 mg/kg based on the pretreatment serum albumin) with a goal to achieve maintenance trough concentrations of 5-10 µg/mL. The primary endpoint is year 1 deep remission defined as a combination of clinical remission (paediatric Crohn's disease activity index<10 (child) or a Crohn's disease activity index<150 (adults)), off prednisone>8 weeks and endoscopic remission (simple endoscopic severity-Crohn's disease≤2).

ETHICS AND DISSEMINATION

). The study protocol has been approved by the Cincinnati Children's Hospital Medical Centre Institutional Review Board. Study results will be disseminated in peer-reviewed journals and presented at scientific meetings.

TRIAL REGISTRATION NUMBER

NCT05660746.

Precision Dosing of Anti-TNF Therapy in Pediatric Inflammatory Bowel Disease

PURPOSE OF THE REVIEW

This review focuses on recent advancements in anti-TNF therapeutic drug monitoring (TDM), pharmacogenetics and personalized drug selection for children with inflammatory bowel disease (IBD).

RECENT FINDINGS

Several real-world studies and one clinical trial in children have demonstrated that proactive TDM, targeting higher exposure concentrations (> 5 µg/mL), can improve disease remission rates and enhance durability of the anti-TNF biologics. Recent data from both adult and pediatric IBD patients have revealed an association between a genetic polymorphism (HLA-DQA1*05) and the development of auto-drug antibodies. The impact of this association on clinical outcomes, considering more routine use proactive TDM and dose optimization in children, is still under investigation. Additionally, recent studies have identified potential inflammatory signatures and biomarkers that may serve as companion diagnostics for anti-TNF biologics. The effective management of anti-TNF therapies in children with IBD requires evidence-based precision dosing strategies, including routine TDM and proactive pharmacodynamic assessments.

Model-informed Precision Dosing for Biologics Is Now Available at the Bedside for Patients With Inflammatory Bowel Disease

It is increasingly recognized that inconsistent biologic therapeutic response is related to pharmacokinetic variability (drug clearance) between patients. This study highlights a multidisciplinary effort to integrate a precision dosing dashboard within the electronic health record to individualize biologic exposure starting and during induction.

Fecal Calprotectin Assay at an Early Stage of Treatment Can Be Used as a Surrogate Marker to Predict Clinical Remission and Mucosal Healing in Pediatric Crohn's Disease

PURPOSE

This study evaluated the predictive role of fecal calprotectin (FC) measured at an early stage of treatment for monitoring clinical remission (CR) after six months and endoscopic remission (ER) after one year of treatment in pediatric Crohn's disease (CD).

METHODS

This retrospective study included 45 patients who simultaneously underwent ileocolonoscopy and FC testing during follow-up. FC levels were measured before and after six weeks of treatment. CR was assessed after six months of treatment using Pediatric Crohn' s Disease Activity Index and acute-phase reactants. ER was assessed after one year using the Simple Endoscopic Score for Crohn's Disease.

RESULTS

Twenty-nine (64.4%) patients used oral prednisolone for remission induction and 16 (35.6%) patients used anti-tumor necrosis factor-alpha. Thirty (66.7%) patients achieved CR, while 24 (53.3%) achieved ER. The FC level measured after six weeks of treatment could predict CR (χ²=9.15, p=0.0025) and ER (χ²=12.31, p=0.0004). The δFC could predict CR (χ²=7.91, p=0.0049), but not ER (χ²=1.85, p=0.1738). With a threshold of ≤950.4 µg/g, FC at week six could predict CR with 76.7% sensitivity and 73.3% specificity. The area under the curve (AUC) was 0.769 (standard error 0.0773, p=0.0005). The same threshold predicted ER with 87.5% sensitivity and 71.4% specificity. The AUC was 0.774 (standard error 0.074, p=0.0002).

CONCLUSION

FC assay at an early stage of treatment can be used as a surrogate marker to predict CR and mucosal healing in pediatric CD.

Infliximab trough level combined with inflammatory biomarkers predict long-term endoscopic outcomes in Crohn’s disease under infliximab therapy

BACKGROUND

Infliximab trough level (ITL) severely affects therapeutic outcomes of Crohn’s disease (CD) patients under infliximab (IFX). Recently, frontier research has focused on identifying ITL based on different therapeutic targets. Although previous studies have elaborated clinical value of ITL monitoring on short-term outcomes in CD patients during therapy, studies contraposing the predictive value of ITL on long-term endoscopic outcomes in CD patients are still scarce domestically and overseas.

AIM

To explore the predictive value of ITL in combination with inflammatory biomarkers on long-term endoscopic outcomes in CD with clinical remission during IFX maintenance therapy.

METHODS

CD patients with endoscopic remission under long-term IFX maintenance therapy in the First Affiliated Hospital of Zhejiang Chinese Medicine University from January 2012 to December 2020 were collected. ITL and inflammatory biomarkers were continuously monitored during the therapy. The Step I study was conducted from weeks 14 to 54 of IFX treatment. The Step II study was conducted from weeks 54 to 108 of IFX treatment. Endoscopic outcomes were defined as endoscopic activity (Crohn’s disease endoscopic index of severity score > 2 points or Rutgeerts score > i1) and endoscopic remission (Crohn’s disease endoscopic index of severity score ≤ 2 points or Rutgeerts ≤ i1). Endoscopic relapse free survival was defined as endoscopic remission at the beginning of the study stage and maintaining endoscopic remission during the study stage.

RESULTS

At week 14, low ITL [odds ratio (OR) = 0.666, 95% confidence interval (CI): 0.514-0.862, P < 0.01] and high fecal calprotectin (FCP) level (OR = 1.002, 95%CI: 1.001-1.004, P < 0.01) increased the risk of endoscopic activity at week 54. At week 54, low ITL (OR = 0.466, 95%CI: 0.247-0.877, P < 0.01) and high C-reactive protein (CRP) level (OR = 1.590, 95%CI: 1.007-2.510, P < 0.01) increased the risk of endoscopic activity at week 108. At week 14, ITL ≤ 5.60 μg/mL [area under the curve (AUC) = 0.83, 95%CI: 0.73-0.90, P < 0.001] and FCP > 238 μg/g (AUC = 0.82, 95%CI: 0.72-0.89, P < 0.001) moderately predicted endoscopic activity at week 54. ITL ≤ 5.60 μg/mL in combination with FCP > 238 μg/g indicated 82.0% possibility of endoscopic activity. At week 54, ITL ≤ 2.10 μg/mL (AUC = 0.85, 95%CI: 0.72-0.93, P < 0.001) and CRP > 3.00 mg/L (AUC = 0.73, 95%CI: 0.60-0.84, P = 0.012) moderately predicted moderate endoscopic activity at week 108. ITL ≤ 2.10 μg/mL in combination with CRP > 3.00 mg/L indicated 100.0% possibility of endoscopic activity. From weeks 14 to 54 of IFX treatment, patients with ITL > 5.60 μg/mL had higher rate of endoscopic relapse free survival than those with ITL ≤ 5.60 μg/mL (95.83% vs 46.67%). From weeks 54 to 108 of IFX treatment, patients with ITL > 2.10 μg/mL had higher rate of endoscopic survival free relapsed rate than those with ITL ≤ 2.10 μg/mL (92.68% vs 30.77%).

CONCLUSION

Combination of ITL, CRP, and FCP contribute to long-term endoscopic prognosis monitoring. During IFX maintenance treatment, low ITL, high CRP level, and high FCP level were independent risk factors of CD patients with clinical remission in adverse endoscopy outcomes within 1-year follow-up.

Tools for the Diagnosis and Management of Crohn's Disease

Numerous tools have emerged over recent decades to aid in the increasingly complex management of patients with Crohn's disease (CD) beyond endoscopy, including video capsule endoscopy, magnetic resonance enterography, computed tomography enterography, a variety of biomarkers, and even wearable biosensors and smartphone applications. These tools have allowed for a more sophisticated and less invasive complementary approach to the evaluation of disease activity and treatment response in patients with CD. This article details the characteristics, practical application, and limitations of these various modalities and discusses how updated guidelines are now incorporating many of them into a treat-to-target strategy.

The SES-CD Could Be a Predictor of Short- and Long-Term Mucosal Healing After Exclusive Enteral Nutrition in Pediatric Crohn's Disease Patients

AIMS

To explore the predictors of mucosal healing (MH) for short- and long-term after exclusive enteral nutrition (EEN) in pediatric Crohn's disease (CD) patients.

METHODS

A retrospective analysis was performed for newly diagnosed active CD patients admitted to our center from January 2017 to 30 December 2020, who were treated with EEN for induction therapy with a minimum of 12 months of follow-up post-EEN. According to the simple endoscopic score for CD (SES-CD), at 1-year post-EEN, 17 patients with an SES-CD < 3 were classified into the sustained MH group (sMH), and 33 patients with an SES-CD ≥ 3 were classified into the sustained non-MH group (sNMH). Statistical methods were used to compare the differences between the two groups and explore the predictors of MH at the end of EEN and 1-year post-EEN.

RESULTS

The SES-CD in the sMH group was lower than that in the sNMH group both at baseline and the end of EEN [sMH vs. sNMH: 8.7 ± 1.2 vs. 16.2 ± 1.0, respectively, p < 0.001 at baseline; 1.0 (3.5) vs. 4.0 (2.0), respectively, p < 0.01 at the end of EEN]. The weighted Pediatric Crohn's Disease Activity Index and erythrocyte sedimentation rate in the sMH group were lower than those in the sNMH group at baseline (both p < 0.05), but showed no difference at the end of EEN. From baseline to 1-year post-EEN, compared with patients in the sNMH group, there were more patients classified with L1 in the sMH group at each time point (all p < 0.001) and fewer patients classified with L3 in the sMH group at baseline and 1-year post-EEN. After EEN, fewer patients received infliximab and had a longer exposure time to infliximab in the sMH group than in the sNMH group. Only the SES-CD at baseline was negatively associated with MH at the end of EEN (OR = 1.40 95% CI = 1.12-1.67, p = 0.00) and 1-year post-EEN (OR = 1.33, 95% CI = 1.12-1.58, p = 0.001), and the cut off value was 11.5.

CONCLUSION

The SES-CD could predict both short- and long-term MH for EEN. Patients with an SES-CD < 11.5 had a high probability of reaching MH by EEN-inducing therapy and maintaining sustained MH at 1-year post-EEN. Patients with an SES-CD greater than 11.5 at baseline should be treated more aggressively with biologics.

Long-term Disease Course of Crohn's Disease: Changes in Disease Location, Phenotype, Activities, and Predictive Factors

Crohn's disease (CD) is a chronic destructive inflammatory bowel disease that affects young people and is associated with significant morbidity. The clinical spectrum and disease course of CD are heterogeneous and often difficult to predict based on the initial presentation. In this article, changes in the disease location, behavior, clinical course during long-term follow-up, and predictive factors are reviewed. Generally, four different patterns of clinical course are discussed: remission, stable disease, chronic relapsing disease, and chronic refractory disease. Understanding the long-term disease course of CD is mandatory to reveal the underlying pathophysiology of the disease and to move toward a more optimistic disease course, such as remission or stability, and less adverse outcomes or devastating sequelae.

STRIDE-II: An Update on the Selecting Therapeutic Targets in Inflammatory Bowel Disease (STRIDE) Initiative of the International Organization for the Study of IBD (IOIBD): Determining Therapeutic Goals for Treat-to-Target strategies in IBD

BACKGROUND

The Selecting Therapeutic Targets in Inflammatory Bowel Disease (STRIDE) initiative of the International Organization for the Study of Inflammatory Bowel Diseases (IOIBD) has proposed treatment targets in 2015 for adult patients with inflammatory bowel disease (IBD). We aimed to update the original STRIDE statements for incorporating treatment targets in both adult and pediatric IBD.

METHODS

Based on a systematic review of the literature and iterative surveys of 89 IOIBD members, recommendations were drafted and modified in 2 surveys and 2 voting rounds. Consensus was reached if ≥75% of participants scored the recommendation as 7 to 10 on a 10-point rating scale.

RESULTS

In the systematic review, 11,278 manuscripts were screened, of which 435 were included. The first IOIBD survey identified the following targets as most important: clinical response and remission, endoscopic healing, and normalization of C-reactive protein/erythrocyte sedimentation rate and calprotectin. Fifteen recommendations were identified, of which 13 were endorsed. STRIDE-II confirmed STRIDE-I long-term targets of clinical remission and endoscopic healing and added absence of disability, restoration of quality of life, and normal growth in children. Symptomatic relief and normalization of serum and fecal markers have been determined as short-term targets. Transmural healing in Crohn's disease and histological healing in ulcerative colitis are not formal targets but should be assessed as measures of the remission depth.

CONCLUSIONS

STRIDE-II encompasses evidence- and consensus-based recommendations for treat-to-target strategies in adults and children with IBD. This frameworkshould be adapted to individual patients and local resources to improve outcomes.

Real-World Infliximab Pharmacokinetic Study Informs an Electronic Health Record-Embedded Dashboard to Guide Precision Dosing in Children with Crohn's Disease

Standard-of-care infliximab dosing regimens were developed prior to the routine use of therapeutic drug monitoring and identification of target concentrations. Not surprisingly, subtherapeutic infliximab concentrations in pediatric Crohn's disease (CD) are common. The primary aim was to conduct a real-world pharmacokinetic (PK) evaluation to discover blood biomarkers of rapid clearance, identify exposure targets, and a secondary aim to translate PK modeling to the clinic. In a multicenter observational study, 671 peak and trough infliximab concentrations from 78 patients with CD were analyzed with a drug-tolerant assay (Esoterix; LabCorp, Calabasas, CA). Individual area under the curve (AUC) estimates were generated as a measure of drug exposure over time. Population PK modeling (nonlinear mixed-effect modeling) identified serum albumin, antibody to infliximab, erythrocyte sedimentation rate (ESR), and neutrophil CD64 as biomarkers for drug clearance. Week 14 and week 52 biochemical remitters (fecal calprotectin < 250 µg/g) had higher infliximab exposure (AUC) throughout induction. The optimal infliximab AUC target during induction for week 14 biochemical remission was 79,348 µg*h/mL (area under the receiver operating characteristic curve (AUROC) 0.77, [0.63-0.90], 85.7% sensitive, and 64.3% specific) with those exceeding the AUC target more likely to achieve a surgery-free week 52 biochemical remission (OR 4.3, [1.2-14.6]). Pretreatment predictors for subtherapeutic week 14 AUC included neutrophil CD64 > 6 (OR 4.5, [1.4-17.8]), ESR > 30 mm/h (OR 3.8, [1.4-11]), age < 10 years old (OR 4.2, [1.2-20]), and weight < 30 kg (OR 6.6, [2.1-25]). We created a decision-support PK dashboard with an iterative process and embedded the modeling program within the electronic health record. Model-informed precision dosing guided by real-world PKs is now available at the bedside in real-time.

The Association Between Genetic Variants, Pharmacokinetics, and Infliximab Efficacy in Pediatric Patients With Crohn's Disease in China

Background: Infliximab is an effective therapy for Crohn's disease (CD). Early non-invasive predictors of disease remission allow for modification of treatments. The aim of this study was to investigate the associations between genetic variants, pharmacokinetics, and infliximab efficacy in pediatric patients with CD. Methods: This retrospective observational study included CD patients under infliximab therapy between August 2015 and December 2020. Information on demographics, laboratory tests, medication data, and disease activity index was collected. The trough levels of infliximab (TLI) and antibodies to infliximab (ATI) were measured at week 14, and reactive drug monitoring was performed during follow-up. Ten single-nucleotide polymorphisms involved in the NF-κB-mediated inflammatory response, pharmacokinetics, and therapeutic response to infliximab were genotyped. Results: A total of 62 pediatric CD patients were enrolled. The clinical remission (CR) rate was 69.4 and 63.2% at week 14 and week 30, respectively. TLI at week 14 was significantly independently associated with CR at week 14 and mucosal healing (MH) at week 30 (p = 0.007 and p = 0.025, respectively). The optimal TLI threshold level capable of distinguishing between the CR and non-CR groups was 2.62 μg/ml (p < 0.001, area under the curve = 0.79, sensitivity = 69.2%, specificity = 78.9%), while that capable of distinguishing between the MH and non-MH groups was 3.34 μg/ml (p < 0.001, area under the curve = 0.85, sensitivity = 78.6%, specificity = 79.4%). Rs3397 in TNFRSF1B was associated with time to ATI production in CD patients (p < 0.001). Conclusions: Higher TLI contributed to achieving MH. Genotyping rs3397 in TNFRSF1B may identify patients who are prone to generating immunogenicity to drugs.

Treat-to-Target in Pediatric Inflammatory Bowel Disease: What Does the Evidence Say?

The traditional management of inflammatory bowel disease, based on treatment intensification guided by clinical activity alone, has been revised in the last 10 years and a treat-to-target approach has been proposed and is currently under evaluation as a disease-modifying strategy. Treat-to-target focuses on objective and scheduled measures to monitor intestinal damage, with consequent therapeutic adjustments in case of failure to achieve pre-defined targets. Identification of targets has been set out by the Selecting Therapeutic Targets in Inflammatory Bowel Disease (STRIDE) committee in 2015. Mucosal healing is universally accepted as the main target both in Crohn's disease and ulcerative colitis, given its proven association with better long-term outcomes than clinical remission alone. Equally important is to ensure patients' clinical remission and improve patient-reported outcomes. Transmural healing (for Crohn's disease) and histological remission (for ulcerative colitis), listed as adjunctive targets, are likely to become primary targets in the near future. The ultimate goal of this approach is to modify the natural history of inflammatory bowel diseases by trying to block bowel damage progression, with interventions in the pre-clinical stage. In this review, we will discuss the current recommended therapeutic targets, as well as those that are considered adjunctive targets, with a focus on the limited pediatric literature available. Prospective long-term trials are warranted in order to identify the most appropriate target for the pediatric population and its specific issues. Identification of reliable predictors of disease course, outcome, and response to treatment will help to individually adapt each step of this monitoring algorithm and consequent therapeutic decision.

Elevated Pretreatment Plasma Oncostatin M Is Associated With Poor Biochemical Response to Infliximab

Background

We hypothesized that elevations of plasma Oncostatin M (OSM) would be associated with infliximab nonresponse.

Methods

Plasma OSM was measured in Crohn disease patients pre-infliximab with biochemical response (>50% reduction in fecal calprotectin) as the primary outcome.

Results

The median OSM in biochemical responders was 86 (69-148) pg/mL compared with 166 (74-1766) pg/mL in nonresponders (P = 0.03). Plasma OSM > 143.5 pg/mL was 71% sensitive and 78% specific for biochemical nonresponse (area under the curve 0.71). Early biochemical nonremission was also associated with an elevated neutrophil CD64 expression (odds ratio 8.9, P = 0.011).

Conclusions

Elevated preinfliximab plasma OSM and nCD64 surface expression were both associated with poor biochemical outcomes.

Clinical value of fecal calprotectin

Inflammatory bowel disease (IBD) denotes a group of chronic incurable disorders characterized by relapsing-remitting inflammation of the gastrointestinal tract. IBD represents a growing global burden with a prevalence exceeding 0.3% in the Western world and an accelerating incidence in newly industrialized countries. The target for treating IBD has shifted in recent years from symptom control to mucosal healing (MH), which has been shown to be associated with favorable long-term outcomes. The gold standard for ascertaining MH is endoscopic assessment, but endoscopy is limited by its invasive nature, high cost, and finite availability. Surrogate biomarkers are therefore of great utility. Calprotectin, a cytosolic protein derived predominantly from neutrophils, is now widely used in this capacity. Calprotectin is found in various bodily fluids at concentrations proportional to the degree of inflammation, including in feces at levels roughly six times higher than in the blood. Fecal calprotectin (FCP) therefore reflects intestinal inflammation. Various assays, including point-of-care and home-based tests, are now available for measuring FCP. FCP is used for screening purposes, to aid in distinguishing inflammatory from non-inflammatory gastrointestinal conditions like irritable bowel syndrome (IBS), as well as in the monitoring of known IBD. The aims of this review are to provide an overview of the methods used to measure FCP and to review the evidence supporting the use of FCP in IBD, particularly as it pertains to screening, monitoring and predicting disease relapse.