Patient factors that increase infliximab clearance and shorten half-life in inflammatory bowel disease: a population pharmacokinetic study

Biomarkers predicting the effect of anti-TNF treatment in paediatric and adult inflammatory bowel disease

OBJECTIVES

Paediatric and adult inflammatory bowel disease (pIBD, aIBD) patients may lose response to anti-tumour necrosis factor (TNF) treatment within the first year. Adult-extrapolated weight-based dosing is incorrect in children, due to age-related pharmacokinetic differences. We investigated biomarkers for initial and maintenance of response to infliximab (IFX) or adalimumab (ADA), comparing pIBD and aIBD patients.

METHODS

In this prospective, observational study, pIBD (n = 24) and aIBD (n = 21) patients were included when initiating anti-TNF. Escalation from standard dosing and continued anti-TNF at 12 and 18 months were assessed. Biomarkers included clinical laboratory parameters, faecal calprotectin (FCP) and IFX trough levels (TLs). Plasma proteomics was performed in pIBD.

RESULTS

During our study, treatment escalation (in clinical loss of response) occurred more common in pIBD versus aIBD (p = 0.02). We established that IFX therapy escalation in pIBD patients was not due to low infliximab levels. We identified 9 pro-inflammatory proteins that were elevated in patients losing response.

CONCLUSION

Anti-TNF exposure-response relationship may be different in pIBD versus aIBD. No biomarkers for maintained response were identified, but 9 inflammatory proteins were of interest as potential predictors for loss of response in pIBD.

Impact of Obesity and Metabolic Syndrome on IBD Outcomes

PURPOSE OF REVIEW

The recent surge in inflammatory bowel disease (IBD) cases has paralleled a significant rise in obesity and metabolic comorbidities rates. In this article, we explore the potential influence of obesity and associated metabolic comorbidities on disease progression, complications, treatment response, surgical outcomes, health economics, and the potential impact of obesity treatment on the course of IBD.

FINDINGS

Contrary to visceral adiposity, obesity does not consistently result in an increased risk of IBD-related complications. Patients with IBD have a higher risk of acute arterial events, likely linked to systemic inflammation. Substantial evidence suggests that obesity has a negative impact on the response to IBD treatment, with this effect being most thoroughly studied in biologics and immunomodulators. The rates of overall complications and post-operative infections are higher in patients who are obese. There are limited but promising data regarding the impact of weight loss techniques, including exercise, medications, and bariatric interventions, on the outcomes in IBD. Both obesity and diabetes have adverse effects on the overall quality of life and place an increased financial burden on the IBD population. A growing body of evidence indicates a connection between obesity and associated metabolic comorbidities and negative outcomes in IBD, yet further efforts are required to fully understand this relationship.

High Body Mass Index and Response to Anti-Tumor Necrosis Factor Therapy in Pediatric Crohn's Disease

INTRODUCTION

Obesity is common among patients with pediatric Crohn's disease (PCD). Some adult studies suggest obese patients respond less well to anti-tumor necrosis factor (TNF) treatment. This study sought compares anti-TNF response and anti-TNF levels between pediatric patients with normal and high body mass index (BMI).

METHODS

The COMBINE trial compared anti-TNF monotherapy with combination therapy with methotrexate in patients with PCD. In this secondary analysis, a comparison of time-to-treatment failure among patients with normal BMI vs BMI Z -score >1, adjusting for prescribed anti-TNF (infliximab [IFX] or adalimumab [ADA]), trial treatment assignment (combination vs monotherapy), and relevant covariates. Median anti-TNF levels across BMI category was also examined.

RESULTS

Of 224 participants (162 IFX initiators and 62 ADA initiators), 111 (81%) had a normal BMI and 43 (19%) had a high BMI. High BMI was associated with treatment failure among ADA initiators (7/10 [70%] vs 12/52 [23%], hazard ratio 0.29, P = 0.007) but not IFX initiators. In addition, ADA-treated patients with a high BMI had lower ADA levels compared with those with normal BMI (median 5.8 vs 12.8 μg/mL, P = 0.02). IFX trough levels did not differ between BMI groups.

DISCUSSION

Overweight and obese patients with PCD are more likely to experience ADA treatment failure than those with normal BMI. Higher BMI was associated with lower drug trough levels. Standard ADA dosing may be insufficient for overweight children with PCD. Among IFX initiators, there was no observed difference in clinical outcomes or drug levels, perhaps due to weight-based dosing and/or greater use of proactive drug monitoring.

Effectiveness and safety of GLP-1 agonist in obese patients with inflammatory bowel disease

BACKGROUND

Obesity affects many patients with inflammatory bowel disease (IBD). Glucagon-like peptide (GLP)-1 agonists are a promising therapy for obese patients. However, there is a lack of evidence of the use of these drugs in IBD populations. We investigated the efficacy and safety of GLP-1 agonists in a cohort of obese patients with IBD.

METHODS

We analyzed a cohort of consecutive IBD patients who received GLP-1 agonists indicated for treating obesity between 2019 and 2021. The GLP-1 agonists included were semaglutide 1.0 mg or liraglutide 3.0 mg. The coprimary endpoints were the percentage of change in body weight from baseline to 6 months and a weight reduction of 5% or more at 6 months. In addition, we reviewed the safety profile of GLP-1 agonist therapy and its impact on the IBD course.

RESULTS

We included 16 obese patients with IBD (9 CD and 7 UC). The median body mass index at baseline was 35 (32-37). The percentage of change in body weight was -6.2% (-3.4-(-8.5)) at 6 months, and a 5% or more weight reduction was achieved in 58.3% (7/12) of patients at 6 months. The most common side effect was nausea (13.3%), and one patient withdrew for diarrhea. IBD activity score did not change significantly during follow-up.

CONCLUSION

Our results showed that GLP-1 agonists were effective and had a good safety profile in IBD patients. Most adverse effects were mild, and the IBD activity had no significant changes.

Therapeutic drug monitoring in inflammatory bowel diseases. Position statement of the Spanish Working Group on Crohn's Disease and Ulcerative Colitis

The treatment of inflammatory bowel disease has undergone a significant transformation following the introduction of biologic drugs. Thanks to these drugs, treatment goals have evolved from clinical response and remission to more ambitious objectives, such as endoscopic or radiologic remission. However, even though biologics are highly effective, a significant percentage of patients will not achieve an initial response or may lose it over time. We know that there is a direct relationship between the trough concentrations of the biologic and its therapeutic efficacy, with more demanding therapeutic goals requiring higher drug levels, and inadequate exposure being common. Therapeutic drug monitoring of biologic medications, along with pharmacokinetic models, provides us with the possibility of offering a personalized approach to treatment for patients with IBD. Over the past few years, relevant information has accumulated regarding its utility during or after induction, as well as in the maintenance of biologic treatment, in reactive or proactive strategies, and prior to withdrawal or treatment de-escalation. The aim of this document is to establish recommendations regarding the utility of therapeutic drug monitoring of biologics in patients with inflammatory bowel disease, in different clinical practice scenarios, and to identify areas where its utility is evident, promising, or controversial.

Performance of Eight Infliximab Population Pharmacokinetic Models in a Cohort of Dutch Children with Inflammatory Bowel Disease

BACKGROUND AND OBJECTIVE

Efficacy of infliximab in children with inflammatory bowel disease can be enhanced when serum concentrations are measured and further dosing is adjusted to achieve and maintain a target concentration. Use of a population pharmacokinetic model may help to predict an individual's infliximab dose requirement. The aim of this study was to evaluate the predictive performance of available infliximab population pharmacokinetic models in an independent cohort of Dutch children with inflammatory bowel disease.

METHODS

In this retrospective study, we used data of 70 children with inflammatory bowel disease (443 infliximab concentrations) to evaluate eight models that focused on infliximab pharmacokinetic models in individuals with inflammatory bowel disease, preferably aged ≤ 18 years. Predictive performance was evaluated with prior predictions (based solely on patient-specific covariates) and posterior predictions (based on covariates and infliximab trough concentrations). Model accuracy and precision were calculated with relative bias and relative root mean square error and we determined the classification accuracy at the trough concentration target of ≥ 5 mg/L.

RESULTS

The population pharmacokinetic model by Fasanmade was identified to be most appropriate for the total dataset (relative bias before/after therapeutic drug monitoring: -20.7%/11.2% and relative root mean square error before/after therapeutic drug monitoring: 84.1%/51.6%), although differences between models were small and several were deemed suitable for clinical use. For the Fasanmade model, sensitivity and specificity for maximum posterior predictions for the next infliximab trough concentration to be ≥ 5 mg/L were respectively 83.5% and 80% with an area under the receiver operating characteristic curve of 0.870.

CONCLUSIONS

In our paediatric cohort, various models provided acceptable predictive performance, with the Fasanmade model deemed most suitable for clinical use. Model-informed precision dosing can therefore be expected to help to maintain infliximab trough concentrations in the target range.

Application of a Precision-Dosing Model to a Real-World Cohort of Patients on Infliximab Maintenance Therapy: Drug Usage and Cost Analysis

Precision-dosing models forecast infliximab doses to achieve targeted trough concentrations in patients with inflammatory bowel disease (IBD). These models have shown to reduce nonresponse and improve patient outcomes. We compared infliximab doses determined by iDOSE precision dosing with standard dosing, and the associated drug costs, in patients with IBD. In this retrospective study, patients with IBD treated with infliximab every 8 weeks at 5 mg/kg were included. An infliximab dose was named dose X if 3 previous infliximab doses, laboratory values including trough infliximab concentrations, and the patient's weight were recorded. The actual dose X was compared to an iDOSE-predicted dose X. Net drug use and costs were evaluated. A total of 174 patients-56% men; median age, 36 (interquartile range, 29-47) years; 135 with Crohn disease; and 31 with ulcerative colitis-were included, with 417 dose X recordings. Median prior infliximab therapy was 2 (0-4) years. Comparing actual dose X with predicted dose X, 52% and 32% of doses were subtherapeutic when aiming for trough concentrations of 5-10 and 3-7 μg/mL, respectively. Treatment costs increased by 102% and 29% for the 2 trough ranges, respectively. On multivariate regression analysis, subtherapeutic infliximab concentrations were associated with ulcerative colitis compared with Crohn disease (odds ratio, 9.81; 95% confidence interval, 1.28-75.40; P = .028) and predose X infliximab trough concentration [odds ratio, 0.07; 95% confidence interval, 0.03-0.15; P < .001]. Over half of maintenance infliximab drug doses were too low to achieve infliximab blood concentrations of 5 μg/mL or greater. While applying precision dosing may improve patient outcomes, drug costs could be considerably greater.

Formation and clearance of TNF-TNF inhibitor complexes during TNF inhibitor treatment

BACKGROUND AND PURPOSE

Millions of patients with inflammatory diseases are treated with tumour necrosis factor (TNF) inhibitors (TNFi). Individual treatment response varies, in part related to variable drug clearance. The role of TNF-TNFi complexes in clearance of the different TNFi is controversial. Moreover, mechanistic insight into the structural aspects and biological significance of TNF-TNFi complexes is lacking. We hypothesized a role for Fc-mediated clearance of TNF-TNFi immune complexes. Therefore, we investigated circulating TNF-TNFi complexes upon treatment with certolizumab-lacking Fc tails-in comparison with adalimumab, golimumab, infliximab and etanercept.

EXPERIMENTAL APPROACH

Drug-tolerant ELISAs were developed and used to quantify TNF during adalimumab, golimumab, etanercept, certolizumab and infliximab treatment in patients with inflammatory arthritis or ulcerative colitis for a maximum follow-up of 1 year. Effects on in vitro TNF production and Fc-mediated uptake of TNF-TNFi complexes were investigated for all five TNFi.

KEY RESULTS

Circulating TNF concentrations were >20-fold higher during certolizumab treatment compared with adalimumab, reaching up to 23.1 ng·ml-1 . Internalization of TNF-TNFi complexes by macrophages depended on Fc valency, with efficient uptake for the full antibody TNFi (three Fc tails), but little or no uptake for etanercept and certolizumab (one and zero Fc tail, respectively). TNF production was not affected by TNFi. Total TNF load did not affect clearance rate of total TNFi.

CONCLUSIONS AND IMPLICATIONS

Differences in TNFi structure profoundly affect clearance of TNF, while it is unlikely that TNF itself significantly contributes to target-mediated drug disposition of TNFi.

CT-based radiomics signature of visceral adipose tissue and bowel lesions for identifying patients with Crohn's disease resistant to infliximab

PURPOSE

To develop a CT-based radiomics model combining with VAT and bowel features to improve the predictive efficacy of IFX therapy on the basis of bowel model.

METHODS

This retrospective study included 231 CD patients (training cohort, n = 112; internal validation cohort, n = 48; external validation cohort, n = 71) from two tertiary centers. Machine-learning VAT model and bowel model were developed separately to identify CD patients with primary nonresponse to IFX. A comprehensive model incorporating VAT and bowel radiomics features was further established to verify whether CT features extracted from VAT would improve the predictive efficacy of bowel model. Area under the curve (AUC) and decision curve analysis were used to compare the prediction performance. Clinical utility was assessed by integrated differentiation improvement (IDI).

RESULTS

VAT model and bowel model exhibited comparable performance for identifying patients with primary nonresponse in both internal (AUC: VAT model vs bowel model, 0.737 (95% CI, 0.590-0.854) vs. 0.832 (95% CI, 0.750-0.896)) and external validation cohort [AUC: VAT model vs. bowel model, 0.714 (95% CI, 0.595-0.815) vs. 0.799 (95% CI, 0.687-0.885)), exhibiting a relatively good net benefit. The comprehensive model incorporating VAT into bowel model yielded a satisfactory predictive efficacy in both internal (AUC, 0.840 (95% CI, 0.706-0.930)) and external validation cohort (AUC, 0.833 (95% CI, 0.726-0.911)), significantly better than bowel alone (IDI = 4.2% and 3.7% in internal and external validation cohorts, both p < 0.05).

CONCLUSION

VAT has an effect on IFX treatment response. It improves the performance for identification of CD patients at high risk of primary nonresponse to IFX therapy with selected features from RM.

CRITICAL RELEVANCE STATEMENT

Our radiomics model (RM) for VAT-bowel analysis captured the pathophysiological changes occurring in VAT and whole bowel lesion, which could help to identify CD patients who would not response to infliximab at the beginning of therapy.

KEY POINTS

• Radiomics signatures with VAT and bowel alone or in combination predicting infliximab efficacy. • VAT features contribute to the prediction of IFX treatment efficacy. • Comprehensive model improved the performance compared with the bowel model alone.

The Impact of Obesity on Inflammatory Bowel Disease

Obesity is prevalent in the inflammatory bowel disease (IBD) population, particularly in newly developed countries where both IBD and obesity in the general population are on the rise. The role of obesity in the pathogenesis of IBD was entertained but results from available studies are conflicting. It does, however, appear to negatively influence disease course whilst impacting on our medical and surgical therapies. The pro-inflammatory profile of the visceral adipose tissue might play a role in the pathogenesis and course of Crohn's Disease (CD). Interestingly, isolating the mesentery from the surgical anastomosis using a KONO-S technique significantly decreases anastomotic recurrence rate. Anti-obesity therapy is not widely used in IBD but was suggested as an adjunctive therapy in those patients. In this review, we aimed to highlight the epidemiology of obesity in IBD and to describe its influence on disease course and outcomes.

Obesity in adult patients with inflammatory bowel disease: Clinical features and impact on disability. A cross-sectional survey from the GETAID

BACKGROUND

In recent years, an increasing prevalence of obesity in inflammatory bowel disease (IBD) has been observed. However, only a few studies have focused on the impact of overweight and obesity on IBD-related disability.

AIMS

To identify the factors associated with obese and overweight patients with IBD, including IBD-related disability.

PATIENTS AND METHODS

In this cross-sectional study, we included 1704 consecutive patients with IBD in 42 centres affiliated with the Groupe d'Etude Therapeutique des Affections Inflammatoires du tube Digestif (GETAID) using a 4-page questionnaire. Factors associated with obesity and overweight were assessed using univariate and multivariate analyses (odds ratios (ORs) are provided with 95% confidence intervals).

RESULTS

The prevalence rates of overweight and obesity were 24.1% and 12.2%, respectively. Multivariable analyses were stratified by age, sex, type of IBD, clinical remission and age at diagnosis of IBD. Overweight was significantly associated with male sex (OR = 0.52, 95% CI [0.39-0.68], p < 0.001), age (OR = 1.02, 95% CI [1.01-1.03], p < 0.001) and body image subscore (OR = 1.15, 95% CI [1.10-1.20], p < 0.001) (Table 2). Obesity was significantly associated with age (OR = 1.03, 95% CI [1.02-1.04], p < 0.001), joint pain subscore (OR = 1.08, 95% CI [1.02-1.14], p < 0.001) and body image subscore (OR = 1.25, 95% CI [1.19-1.32], p < 0.001) (Table 3).

CONCLUSION

The increasing prevalence of overweight and obesity in patients with IBD is associated with age and poorer body image. A holistic approach to IBD patient care should be encouraged to improve IBD-related disability and to prevent rheumatological and cardiovascular complications.

Enhancing Therapeutic Drug Monitoring in Inflammatory Bowel Disease: A Comparative Analysis of Rapid Point-of-Care Infliximab, Adalimumab and Anti-Drug Antibodies' Determination against ELISA

The introduction of point-of-care (POC) assays into clinical practice in patients with inflammatory disease enables on-demand therapeutic decision making. The aim of this study was to compare the POC test Quantum blue (Bühlmann Laboratories) for infliximab (IFX), adalimumab (ADL), and its anti-drug antibodies with the traditional ELISA assay (Promonitor). A total of 200 serum samples were analyzed. Samples were classified into the following three different groups; sub-therapeutic range (IFX < 3 μg/mL and ADL < 5 μg/mL); therapeutic range (IFX: 3-7 μg/mL and ADL: 5-12 μg/mL) and supra-therapeutic range (IFX levels > 7 μg/mL and ADL levels > 12 μg/mL). Significant higher values were measured using the POC test (p < 0.001) for IFX results but no differences in ADL trough levels were observed (p = 0.3101). Spearman's correlation indicated a good correlation between the two assays (rs = 0.88 for ADL and rs = 0.93 for IFX), and McNemar's test revealed significant differences (p = 0.016) when classifying IFX samples between therapeutic and supra-therapeutic ranges but no significant differences were found among the other ranges for either IFX or ADL. These results show that we should be cautious when using these rapid measurement methods, and new targets should probably be defined for IFX when using this new analytical method.

Point-of-care therapeutic drug monitoring of tumour necrosis factor-α inhibitors using a single step immunoassay

Therapeutic drug monitoring (TDM) of tumor necrosis factor-α (TNFα)-inhibitors adalimumab and infliximab is important to establish optimal drug dose and maximize treatment efficacy. Currently, TDM is primarily performed with ELISA techniques in clinical laboratories, resulting in a long sample-to-result workflow. Point-of-care (POC) detection of these therapeutic antibodies could significantly decrease turnaround times and allow for user-friendly home-testing. Here, we adapted the recently developed bioluminescent dRAPPID (dimeric Ratiometric Plug-and-Play Immunodiagnostics) sensor platform to allow POC TDM of infliximab and adalimumab. We applied the two best performing dRAPPID sensors, with limit-of-detections of 1 pM and 17 pM, to measure the infliximab and adalimumab levels in 49 and 40 patient serum samples, respectively. The analytical performance of dRAPPID was benchmarked with commercial ELISAs and yielded Pearson's correlation coefficients of 0.93 and 0.94 for infliximab and adalimumab, respectively. Furthermore, a dedicated bioluminescence reader was fabricated and used as a readout device for the TDM dRAPPID sensors. Subsequently, infliximab and adalimumab patient serum samples were measured with the TDM dRAPPID sensors and bioluminescence reader, yielding Pearson's correlation coefficients of 0.97 and 0.86 for infliximab and adalimumab, respectively, and small proportional differences with ELISA (slope was 0.97 ± 0.09 and 0.96 ± 0.20, respectively). The adalimumab and infliximab dRAPPID sensors, in combination with the dedicated bioluminescence reader, allow for ease-of-use TDM with a fast turnaround time and show potential for POC TDM outside of clinical laboratories.

Patients With Inflammatory Bowel Diseases and Higher Visceral Adipose Tissue Burden May Benefit From Higher Infliximab Concentrations to Achieve Remission

INTRODUCTION

In patients with inflammatory bowel diseases (IBDs), high visceral adipose tissue (VAT) burden is associated with a lower response to infliximab, potentially through alterations in volume distribution and/or clearance. Differences in VAT may also explain the heterogeneity in target trough levels of infliximab associated with favorable outcomes. The aim of this study was to assess whether VAT burden may be associated with infliximab cutoffs associated with efficacy in patients with IBD.

METHODS

We conducted a prospective cross-sectional study of patients with IBD receiving maintenance infliximab therapy. We measured baseline body composition parameters (Lunar iDXA), disease activity, trough levels of infliximab, and biomarkers. The primary outcome was steroid-free deep remission. The secondary outcome was endoscopic remission within 8 weeks of infliximab level measurement.

RESULTS

Overall, 142 patients were enrolled. The optimal trough levels of infliximab cutoffs associated with steroid-free deep remission and endoscopic remission were 3.9 mcg/mL (Youden Index [J]: 0.52) for patients in the lowest 2 VAT % quartiles (<1.2%) while optimal infliximab level cutoffs associated with steroid-free deep remission for those patients in the highest 2 VAT % quartiles was 15.3 mcg/mL (J: 0.63). In a multivariable analysis, only VAT % and infliximab level remained independently associated with steroid-free deep remission (odds ratio per % of VAT: 0.3 [95% confidence interval: 0.17-0.64], P < 0.001 and odds ratio per μg/mL: 1.11 [95% confidence interval: 1.05-1.19], P < 0.001).

DISCUSSION

The results may suggest that patients with higher visceral adipose tissue burden may benefit from achieving higher infliximab levels to achieve remission.

Nutrition, Nutritional Status, Micronutrients Deficiency, and Disease Course of Inflammatory Bowel Disease

During the disease course, most Inflammatory Bowel Disease patients present a condition of malnutrition, undernutrition, or even overnutrition. These conditions are mainly due to suboptimal nutritional intake, alterations in nutrient requirements and metabolism, malabsorption, and excessive gastrointestinal losses. A suboptimal nutritional status and low micronutrient serum levels can have a negative impact on both induction and maintenance of remission and on the quality of life of Inflammatory Bowel Disease patients. We performed a systematic review including all the studies evaluating the connection between nutrition, nutrition status (including undernutrition and overnutrition), micronutrient deficiency, and both disease course and therapeutic response in Inflammatory Bowel Disease patients. This systematic review was performed using PubMed/MEDLINE and Scopus. Four main clinical settings concerning the effect of nutrition on disease course in adult Inflammatory Bowel Disease patients were analyzed (induction of remission, maintenance of remission, risk of surgery, post-operative recurrence, and surgery-related complications). Four authors independently reviewed abstracts and manuscripts for eligibility. 6077 articles were found; 762 duplicated studies were removed. Out of 412 full texts analyzed, 227 were included in the review. The evidence summarized in this review showed that many nutritional aspects could be potential targets to induce a better control of symptoms, a deeper remission, and overall improve the quality of life of Inflammatory Bowel Disease patients.

Predictors and optimal management of tumor necrosis factor antagonist nonresponse in inflammatory bowel disease: A literature review

Tumor necrosis factor-α (TNF-α) antagonists, the first biologics approved for treating patients with inflammatory bowel disease (IBD), are effective for the induction and maintenance of remission and significantly improving prognosis. However, up to one-third of treated patients show primary nonresponse (PNR) to anti-TNF-α therapies, and 23%-50% of IBD patients experience loss of response (LOR) to these biologics during subsequent treatment. There is still no recognized predictor for evaluating the efficacy of anti-TNF drugs. This review summarizes the existing predictors of PNR and LOR to anti-TNF in IBD patients. Most predictors remain controversial, and only previous surgical history, disease manifestations, drug concentrations, antidrug antibodies, serum albumin, some biologic markers, and some genetic markers may be potentially predictive. In addition, we also discuss the next steps of treatment for patients with PNR or LOR to TNF antagonists. Therapeutic drug monitoring plays an important role in treatment selection. Dose escalation, combination therapy, switching to a different anti-TNF drug, or switching to a biologic with a different mechanism of action can be selected based on the concentration of the drug and/or antidrug antibodies.

Advantage of First-Line Therapeutic Drug Monitoring-Driven Use of Infliximab for Treating Acute Intestinal and Liver GVHD in Children: A Prospective, Single-Center Study

The high serum concentrations of TNF-α characterize acute graft-versus-host disease (aGVHD), for which infliximab treatment may be beneficial. In 28 pediatric patients, four doses of 10 mg/kg infliximab every seven days were administered after steroid failure (Standard Group, n = 14) or as a first-line therapy (Early Group, n = 14). Population pharmacokinetic analyses and evaluation of serum cytokines were performed. After two months of treatment, complete response in gastrointestinal and liver aGVHD was achieved in 43% and 100% of patients in the Standard and Early groups, respectively. During follow-up, four patients in the Standard Group (but none in the Early Group) experienced an aGVHD recurrence. Viral infections occurred more frequently in the Standard Group after the fifth dose. Infliximab clearance did not differ between groups or according to treatment outcome for each organ involved in aGVHD, whereas serum levels of cytokines significantly differed. Therefore, present findings show that use of first-line, TDM-driven infliximab to treat aGVHD in children may result in better clinical outcomes and tolerability, with a different pattern of cytokines generated according to the moment of beginning of treatment.

In-hospital management of inflammatory bowel disease

PURPOSE OF REVIEW

The management of hospitalized patients with inflammatory bowel disease (IBD) is complex. Despite considerable therapeutic advancements in outpatient ulcerative colitis and Crohn's disease management, the in-hospital management continues to lag with suboptimal outcomes. The purpose of this review is to provide a brief overview of our approach to managing patients hospitalized with acute severe ulcerative colitis (ASUC) and Crohn's disease-related complications, followed by a summary of emerging evidence for new management approaches.

RECENT FINDINGS

ASUC has seen the emergence of well validated prognostic models for colectomy as well as the development of novel treatment strategies such as accelerated infliximab dosing, Janus kinase inhibitor therapy, and sequential therapy, yet the rate of colectomy for steroid-refractory ASUC has not meaningfully improved. Crohn's disease has seen the development of better diagnostic tools, early Crohn's disease-related complication stratification and identification, as well as better surgical techniques, yet the rates of hospitalization and development of Crohn's disease-related complications remain high.

SUMMARY

Significant progress has been made in the in-hospital IBD management; however, both the management of ASUC and hospitalized Crohn's disease remain a challenge with suboptimal outcomes. Critical knowledge gaps still exist, and dedicated studies in hospitalized patients with IBD are needed to address them.

Infliximab vs adalimumab: Points to consider when selecting anti-tumor necrosis factor agents in pediatric patients with Crohn’s disease

Biologic agents with various mechanisms against Crohn’s disease (CD) have been released and are widely used in clinical practice. However, two anti-tumor necrosis factor (TNF) agents, infliximab (IFX) and adalimumab (ADL), are the only biologic agents approved by the Food and Drug Administration for pediatric CD currently. Therefore, in pediatric CD, the choice of biologic agents should be made more carefully to achieve the therapeutic goal. There are currently no head-to-head trials of biologic agents in pediatric or adult CD. There is a lack of accumulated data for pediatric CD, which requires the extrapolation of adult data for the positioning of biologics in pediatric CD. From a pharmacokinetic point of view, IFX is more advantageous than ADL when the inflammatory burden is high, and ADL is expected to be advantageous over IFX in sustaining remission in the maintenance phase. Additionally, we reviewed the safety profile, immunogenicity, preference, and compliance between IFX and ADL and provide practical insights into the choice of anti-TNF therapy in pediatric CD. Careful evaluation of clinical indications and disease behavior is essential when prescribing anti-TNF agents. In addition, factors such as the efficacy of induction and maintenance of remission, safety profile, immunogenicity, patient preference, and compliance play an important role in evaluating and selecting treatment options.

Therapeutic Drug Monitoring of Infliximab in Acute Severe Ulcerative Colitis

Therapeutic drug monitoring (TDM) is a useful strategy in ulcerative colitis (UC). Nearly a quarter of UC patients will experience acute severe UC (ASUC) in their lifetime, including 30% who will fail first-line corticosteroid therapy. Steroid-refractory ASUC patients require salvage therapy with infliximab, cyclosporine, or colectomy. Fewer data are available for the use of TDM of infliximab in ASUC. The pharmacokinetics of ASUC make TDM in this population more complex. High inflammatory burden is associated with increased infliximab clearance, which is associated with lower infliximab drug concentrations. Observational data support the association between increased serum infliximab concentrations, lower clearance, and favorable clinical and endoscopic outcomes, as well as decreased rates of colectomy. Data regarding the benefit of accelerated or intensified dosing strategies of infliximab-as well as target drug concentration thresholds-in ASUC patients remain more equivocal, though limited by their observational nature. Studies are underway to further evaluate optimal dosing and TDM targets in this population. This review examines the evidence for TDM in patients with ASUC, with a focus on infliximab.

Trough Concentration Response in Infliximab and Adalimumab Treated Children With Inflammatory Bowel Disease Following Treatment Adjustment: A Pharmacokinetic Model

OBJECTIVES

In patients with inflammatory bowel diseases (IBD), data on trough concentration (TC) response to adjustments of anti-tumor necrosis factor (TNFα) are scarce.

METHODS

We included pediatric patients with IBD who were treated with anti-TNFα agents and had sequential monitoring of TC pre- and post-adjustment. Patients with positive anti-drug-antibodies or with concomitant change in immunomodulatory treatment were excluded.

RESULTS

For the entire cohort (86 patients), median age at diagnosis was 13.2 (interquartile range, 10.7-14.9) years [females, 48%; Crohn disease (CD), 72%]. For infliximab, 58 patients had 201 interval changes and 26 had dose increase. Increase in TC following dose increase could not be predicted due to significant variability (P = 0.9). For every 10% decrease in interval, TC was increased by 1.6 µg/mL or by 57.2% (P = 0.014). Perianal disease was associated with attenuated response. For every 10% increase in interval, TC was decreased by 0.66 µg/mL or by 4.2%. The diagnosis of CD was associated with reduced response to interval increase. For adalimumab, 28 patients had 31 and 12 events of interval decrease or increase, respectively. Interval decrease resulted in increased median TC from 4.5 (3.5-5.3) µg/mL to 8.1 (6.5-10.5) µg/mL (X1.8) while interval increase resulted in TC change from 15.5 (12.8-18.6) µg/mL to 9.7 (6.5-14.6) µg/mL (:1.6) (P < 0.001 for both). Increase in delta TC was associated with younger age, and with absence of perianal disease (P = 0.001).

CONCLUSION

Changes in TC following treatment adjustment can be almost linearly predicted for adalimumab while response to infliximab adjustment are more variable.

Decreased Infliximab Concentrations in Patients With Inflammatory Bowel Disease Who Carry a Variable Number Tandem Repeat Polymorphism in the Neonatal Fc Receptor or Variant HLADQA1*05G>A Genotype

BACKGROUND

Multiple variables contribute to variation in patient exposure and response to tumor necrosis factor alpha antagonist biologics such as infliximab. This study aimed to assess the association between maintenance-phase infliximab concentrations and genetic variation in HLADQA1*05G>A and fragment crystallisable (Fc) fragment of IgG receptor and transporter (FCGRT) among patients with inflammatory bowel disease.

METHODS

A cross-sectional study was carried out in participants with inflammatory bowel disease prescribed infliximab who were in the maintenance phase of treatment. Participants were genotyped for the presence of the FCGRT variable number tandem repeat (VNTR) and HLADQA1*05G>A (rs74291249). A point estimate of the infliximab trough concentration during the maintenance phase was determined using a standard enzyme-linked immunosorbent assay for each patient. Other variables associated with infliximab pharmacokinetics were collected.

RESULTS

A total of 156 participants with inflammatory bowel disease were included from 2 tertiary care centers affiliated with Western University, London, Canada. Median infliximab trough concentrations were lower in participants who carried the FCGRT VNTR 2/3 or 2/2 (4.14 µg/mL; interquartile range [IQR], 6.48 µg/mL) vs wild type individuals (7.00 µg/mL; IQR, 7.66; P = .0027). Median infliximab trough concentrations were significantly lower in participants who were HLADQA1*05G>A variant carriers (4.73µg/mL; IQR, 4.79) vs wild type individuals (7.85µg/mL; IQR, 7.44; P = .0006). A significant decrease in infliximab trough concentrations was seen in individuals who were dual carriers of variant polymorphisms in HLADQA1*05G>A and FCGRT VNTR (no variants, 8.96µg/mL; IQR, 6.84 vs one variant, 4.96 µg/mL; IQR, 4.95 vs dual variants, 0.86µg/mL; IQR, 5.82).

CONCLUSION

FCGRT VNTR and HLADQA1*05G>A are associated with lower maintenance-phase infliximab concentrations, particularly among patients who carry both variants.

GADECCU 2022 Guideline for the treatment of Ulcerative Colitis. Adaptation and updating of the GETECCU 2020 Guideline

INTRODUCTION

Ulcerative colitis (UC) is a chronic inflammatory disease that compromises the colon, affecting the quality of life of individuals of any age. In practice, there is a wide spectrum of clinical situations. The advances made in the physio pathogenesis of UC have allowed the development of new, more effective and safer therapeutic agents.

OBJECTIVES

To update and expand the evaluation of the efficacy and safety of relevant treatments for remission induction and maintenance after a mild, moderate or severe flare of UC.

RECIPIENTS

Gastroenterologists, coloproctologists, general practitioners, family physicians and others health professionals, interested in the treatment of UC.

METHODOLOGY

GADECCU authorities obtained authorization from GETECCU to adapt and update the GETECCU 2020 Guide for the treatment of UC. Prepared with GRADE methodology. A team was formed that included authors, a panel of experts, a nurse and a patient, methodological experts, and external reviewers. GRADE methodology was used with the new information.

RESULTS

A 118-page document was prepared with the 44 GADECCU 2022 recommendations, for different clinical situations and therapeutic options, according to levels of evidence. A section was added with the new molecules that are about to be available.

CONCLUSIONS

This guideline has been made in order to facilitate decision-making regarding the treatment of UC, adapting and updating the guide prepared by GETECCU in the year 2020.

Precision medicine and drug optimization in adult inflammatory bowel disease patients

Inflammatory bowel diseases (IBD) encompass two main entities including ulcerative colitis and Crohn's disease. Although having a common global pathophysiological mechanism, IBD patients are characterized by a significant interindividual heterogeneity and may differ by their disease type, disease locations, disease behaviours, disease manifestations, disease course as well as treatment needs. Indeed, although the therapeutic armamentarium for these diseases has expanded rapidly in recent years, a proportion of patients remains with a suboptimal response to medical treatment due to primary non-response, secondary loss of response or intolerance to currently available drugs. Identifying, prior to treatment initiation, which patients are likely to respond to a specific drug would improve the disease management, avoid unnecessary side effects and reduce the healthcare expenses. Precision medicine classifies individuals into subpopulations according to clinical and molecular characteristics with the objective to tailor preventative and therapeutic interventions to the characteristics of each patient. Interventions would thus be performed only on those who will benefit, sparing side effects and expense for those who will not. This review aims to summarize clinical factors, biomarkers (genetic, transcriptomic, proteomic, metabolic, radiomic or from the microbiota) and tools that could predict disease progression to guide towards a step-up or top-down strategy. Predictive factors of response or non-response to treatment will then be reviewed, followed by a discussion about the optimal dose of drug required for patients. The time at which these treatments should be administered (or rather can be stopped in case of a deep remission or in the aftermath of a surgery) will also be addressed. IBD remain biologically complex, with multifactorial etiopathology, clinical heterogeneity as well as temporal and therapeutic variabilities, which makes precision medicine especially challenging in this area. Although applied for many years in oncology, it remains an unmet medical need in IBD.

Early Infliximab Clearance Predicts Remission in Children with Crohn's Disease

BACKGROUND AND AIMS

Children with Crohn's disease have lower response rates to infliximab, lower infliximab levels, and higher infliximab clearance on weight-based dosing than adults. We hypothesize infliximab clearance is a predictive of later outcomes on infliximab in children with Crohn's disease.

METHODS

In this single-center retrospective study, data were collected from charts on diagnosis, anthropometry, routine labs, infliximab therapeutic drug monitoring, infliximab dosing, disease activity, and other treatments. With these data we generated a population pharmacokinetic model using non-linear mixed effects modeling and calculated infliximab clearance for each patient over time. Patients were classified as in remission, responder-only or non-responder at 5, 10 and 16 months. Regression and ROC analyses were used to assess for early predictors of remission and response to infliximab.

RESULTS

Eighty-five subjects were included, with a median follow-up of 22.3 months (IQR 10.1-36.8). Our pharmacokinetic model showed infliximab clearance was positively associated with CRP and weight, while negatively associated with albumin. In regression analyses, early infliximab clearance was the only significant, consistent predictor of remission. A 0.1 L/day increase in infliximab clearance predicted remission with an OR between 0.179 and 0.426. Differences in dosing did not account for differences in outcome. Infliximab clearance alone had moderate predictive accuracy of remission, with an AUC between 0.682 and 0.738.

CONCLUSIONS

Early infliximab clearance is strongly associated with remission in children with Crohn's disease. It may be useful as a marker of response in proactive therapeutic drug monitoring to guide early dose optimization and/or changes in treatment for betterment of long-term outcomes.

Timing of Live Attenuated Vaccination in Infants Exposed to Infliximab or Adalimumab in Utero: A Prospective Cohort Study in 107 Children

BACKGROUND AND AIMS

For infants exposed in utero to anti-tumour necrosis factor-α [TNF] medications, it is advised that live-attenuated vaccinations be postponed until the drug is cleared, but little is known about time to clearance. To minimize delays before live-attenuated vaccination can be given, we aimed to develop a pharmacokinetic model to predict time-to-clearance in infants exposed during pregnancy.

METHODS

We prospectively followed in utero infliximab/adalimumab-exposed infants of mothers with inflammatory bowel disease across four countries between 2011 and 2018. Infants with a detectable anti-TNF umbilical-cord level and at least one other blood sample during the first year of life were included.

RESULTS

Overall, 107 infants were enrolled, including 166 blood samples from 71 infliximab-exposed infants and 77 samples from 36 adalimumab-exposed infants. Anti-TNF was detectable in 23% [n = 25] of infants at 6 months. At 12 months, adalimumab was not detected but 4% [n = 3] had detectable infliximab. A Bayesian forecasting method was developed using a one-compartment pharmacokinetic model. Model validation showed that the predicted clearing time was in accordance with the measured observations. A clinician-friendly online calculator was developed for calculating full anti-TNF clearing time: https://xiaozhu.shinyapps.io/antiTNFcalculator2/.

CONCLUSIONS

Almost one-quarter of infants born to mothers receiving anti-TNF during pregnancy have detectable anti-TNF at 6 months. To limit the time to live-attenuated vaccination in infants of mothers receiving anti-TNF during pregnancy, the results of a cord drug level at birth and a second sample ≥ 1 month thereafter can be used to estimate the time for full anti-TNF clearance in these children.

Effect of Obesity on Risk of Hospitalization, Surgery, and Serious Infection in Biologic-Treated Patients With Inflammatory Bowel Diseases: A CA-IBD Cohort Study

INTRODUCTION

Obesity is variably associated with treatment response in biologic-treated patients with inflammatory bowel diseases (IBD). We evaluated the association between obesity and risk of hospitalization, surgery, or serious infections in patients with IBD in new users of biologic agents in a large, multicenter, electronic health record (EHR)-based cohort (CA-IBD).

METHODS

We created an EHR-based cohort of adult patients with IBD who were new users of biologic agents (tumor necrosis factor [TNF-α] antagonists, ustekinumab, and vedolizumab) between January 1, 2010, and June 30, 2017, from 5 health systems in California. Patients were classified as those with normal body mass index (BMI), overweight, or obese based on the World Health Organization classification. We compared the risk of all-cause hospitalization, IBD-related surgery, or serious infections among patients with obesity vs those overweight vs those with normal BMI, using Cox proportional hazard analyses, adjusting for baseline demographic, disease, and treatment characteristics.

RESULTS

Of 3,038 biologic-treated patients with IBD (69% with Crohn's disease and 76% on TNF-α antagonists), 28.2% (n = 858) were overweight, and 13.7% (n = 416) were obese. On a follow-up after biologic initiation, obesity was not associated with an increased risk of hospitalization (adjusted hazard ratio [aHR] vs normal BMI, 0.90; [95% confidence interval, 0.72-1.13]); IBD-related surgery (aHR, 0.62 [0.31-1.22]); or serious infection (aHR, 1.11 [0.73-1.71]). Similar results were observed on stratified analysis by disease phenotype (Crohn's disease vs ulcerative colitis) and index biologic therapy (TNF-α antagonists vs non-TNF-α antagonists).

DISCUSSION

In a multicenter, EHR-based cohort of biologic-treated patients with IBD, obesity was not associated with hospitalization, surgery, or serious infections. Further studies examining the effect of visceral obesity on patient-reported and endoscopic outcomes are needed.

Ulcerative Colitis and Acute Severe Ulcerative Colitis Patients Are Overlooked in Infliximab Population Pharmacokinetic Models: Results from a Comprehensive Review

Ulcerative colitis (UC) is part of the inflammatory bowels diseases, and moderate to severe UC patients can be treated with anti-tumour necrosis α monoclonal antibodies, including infliximab (IFX). Even though treatment of UC patients by IFX has been in place for over a decade, many gaps in modelling of IFX PK in this population remain. This is even more true for acute severe UC (ASUC) patients for which early prediction of IFX pharmacokinetic (PK) could highly improve treatment outcome. Thus, this review aims to compile and analyse published population PK models of IFX in UC and ASUC patients, and to assess the current knowledge on disease activity impact on IFX PK. For this, a semi-systematic literature search was conducted, from which 26 publications including a population PK model analysis of UC patients receiving IFX therapy were selected. Amongst those, only four developed a model specifically for UC patients, and only three populations included severe UC patients. Investigations of disease activity impact on PK were reported in only 4 of the 14 models selected. In addition, the lack of reported model codes and assessment of predictive performance make the use of published models in a clinical setting challenging. Thus, more comprehensive investigation of PK in UC and ASUC is needed as well as more adequate reports on developed models and their evaluation in order to apply them in a clinical setting.

Multi‐model averaging improves the performance of model‐guided infliximab dosing in patients with inflammatory bowel diseases

Infliximab dosage de‐escalation without prior knowledge of drug concentrations may put patients at risk for underexposure and trigger the loss of response. A single‐model approach for model‐informed precision dosing during infliximab maintenance therapy has proven its clinical benefit in patients with inflammatory bowel diseases. We evaluated the predictive performances of two multi‐model approaches, a model selection algorithm and a model averaging algorithm, using 18 published population pharmacokinetic models of infliximab for guiding dosage de‐escalation. Data of 54 patients with Crohn’s disease and ulcerative colitis who underwent infliximab dosage de‐escalation after an earlier escalation were used. A priori prediction (based solely on covariate data) and maximum a posteriori prediction (based on covariate data and trough concentrations) were compared using accuracy and precision metrics and the classification accuracy at the trough concentration target of 5.0 mg/L. A priori prediction was inaccurate and imprecise, with the lowest classification accuracies irrespective of the approach (median 59%, interquartile range 59%–63%). Using the maximum a posteriori prediction, the model averaging algorithm had systematically better predictive performance than the model selection algorithm or the single‐model approach with any model, regardless of the number of concentration data. Only a single trough concentration (preferably at the point of care) sufficed for accurate and precise prediction. Predictive performance of both single‐ and multi‐model approaches was robust to the lack of covariate data. Model averaging using four models demonstrated similar predictive performance with a five‐fold shorter computation time. This model averaging algorithm was implemented in the TDMx software tool to guide infliximab dosage de‐escalation in the forthcoming prospective MODIFI study (NCT04982172).

Short interruptions of TNF-inhibitor treatment can be associated with treatment failure in patients with immune-mediated diseases

INTRODUCTION

The prevalence of immune-mediated diseases has increased in the past decades and despite the use of biological treatments all patients do not achieve remission. The aim of this study was to characterise the reasons for short interruptions during treatment with two commonly used TNF-inhibitors infliximab and adalimumab and to analyse the possible effects of the interruptions on immunisation and switching the treatment.

MATERIAL AND METHODS

This case-control study was based on retrospective analyses of patient records and a questionnaire survey to clinicians. A total of 370 patients (194 immunised cases and 172 non-immunised controls, 4 excluded) were enrolled from eight hospitals around Finland. Eleven different diagnoses were represented, and the largest patient groups were those with inflammatory bowel or rheumatic diseases.

RESULTS

Treatment interruptions were associated with immunisation in patients using infliximab (p < .001) or adalimumab (p < .000001). Patients with treatment interruptions were more likely to have been treated with more than one biological agent compared to those without treatment interruptions. This was particularly prominent among patients with a rheumatic disease (p < .00001). The most frequent reason for a treatment interruption among the cases was an infection, whereas among the control patients it was remission. The median length of one interruption was one month (interquartile range 1-3 months).

CONCLUSION

Our results suggest that the interruptions of the treatment with TNF-inhibitors expose patients to immunisation and increase the need for drug switching. These findings stress the importance of careful judgement of the need for a short interruption in the biological treatment in clinical work, especially during non-severe infections.

Higher infliximab and adalimumab trough levels are associated with fistula healing in patients with fistulising perianal Crohn’s disease

BACKGROUND

Tumor necrosis factor-alpha inhibitors, including infliximab and adalimumab, are effective medical treatments for perianal fistulising Crohn’s disease (CD), but not all patients achieve fistula healing.

AIM

To determine the correlation between perianal fistula healing and closure with infliximab and adalimumab trough levels.

METHODS

In this multicentre retrospective study conducted across four tertiary inflammatory bowel disease centres in Australia, we identified CD patients with perianal fistulae on maintenance infliximab or adalimumab who had a trough level within twelve weeks of clinical assessment. Data collected included demographics, serum infliximab and adalimumab trough levels (mg/L) within 12 wk before or after their most recent clinical assessment and concomitant medical or surgical therapy. The primary outcome was fistula healing, defined as cessation in fistula drainage. The secondary outcome was fistula closure, defined as healing and closure of all external fistula openings. Differences between patients who did or did not achieve fistula healing were compared using the chi-square test, t test or Mann-Whitney U test.

RESULTS

One hundred and fourteen patients (66 infliximab, 48 adalimumab) were included. Forty-eight (72.7%) patients on maintenance infliximab achieved fistula healing and 18 (27.3%) achieved fistula closure. Thirty-seven (77%) patients on maintenance adalimumab achieved fistula healing and 17 (35.4%) achieved fistula closure. Patients who achieved fistula healing had significantly higher infliximab and adalimumab trough levels than patients who did not [infliximab: 6.4 (3.8-9.5) vs 3.0 (0.3-6.2) mg/L, P = 0.003; adalimumab: 9.2 (6.5-12.0) vs 5.4 (2.5-8.3) mg/L, P = 0.004]. For patients on infliximab, fistula healing was associated with lower rates of detectable anti-infliximab antibodies and younger age. For patients on adalimumab, fistula healing was associated with higher rates of combination therapy with an immunomodulator. Serum trough levels for patients with and without fistula closure were not significantly different for infliximab [6.9 (4.3-10.2) vs 5.5 (2.5-8.3) mg/L, P = 0.105] or adalimumab [10.0 (6.6-12.0) vs 7.8 (4.2-10.0) mg/L, P = 0.083].

CONCLUSION

Higher maintenance infliximab and adalimumab trough levels are associated with perianal fistula healing in CD.

Therapeutic Drug Monitoring of Biologics in Crohn's Disease

Reactive therapeutic drug monitoring (TDM) is considered the standard of care for optimizing biologics in inflammatory bowel disease (IBD) including Crohn's disease (CD). Preliminary data show that proactive TDM is associated with positive outcomes in IBD and can be also used to efficiently guide therapeutic decisions in specific clinical scenarios. Higher biological drug concentrations are associated with favorable therapeutic outcomes in specific IBD populations or phenotypes including pediatric CD, perianal fistulizing CD, small bowel CD, and following an ileocolonic resection for CD. Future perspectives of TDM include the use of rapid testing, pharmacogenomics, and pharmacokinetic dashboards toward individualized therapy.

BMI is important in predicting the loss of response in inflammatory bowel disease patients on tumour necrosis factor-α inhibitors

INTRODUCTION

Obesity is an emerging phenomenon among patients with inflammatory bowel disease (IBD). This study aims to evaluate whether the response to tumour necrosis factor-α (TNF-α) inhibitors (infliximab and adalimumab) could be influenced by BMI in IBD.

METHODS

We identified a cohort of 181 IBD patients attending a single-tertiary centre, naive to biologic therapy and stratified them according to their BMI. The primary outcome is the first occurrence of loss of response (LOR).

RESULTS

The median BMI was 26 kg/m2 (15-63 kg/m2). Approximately 68% of patients had LOR on both adalimumab (ADA) (n = 52) and infliximab (IFX) (n = 71). However, 83% on ADA with BMI ≥30 kg/m2 had LOR compared to 61% on IFX with BMI ≥30 kg/m2. For patients on ADA, Cox regression analysis revealed that after accounting for age, sex, disease type, duration of disease, fistulising disease, smoking status, haemoglobin, C-reactive protein, albumin and platelet levels, there were statistically significant associations between BMI (≥30 kg/m2 vs. <30 kg/m2) and LOR [P = 0.010; hazard ratio (HR) 3.2; confidence interval (CI), 1.3-7.6]. However, for patients on IFX, after accounting for the same factors, the only significant factor was the association of lower rate of LOR with higher albumin levels (P = 0.024; HR 0.95; CI, 0.91-0.99). There was an increased accelerated time to LOR for patients on ADA with BMI ≥30 kg/m2 compared to BMI <30 kg/m2 (P = 0.026). However, there was no difference in time to LOR for patients on IFX (P = 0.177).

CONCLUSION

BMI is important in predicting the LOR among IBD patients on TNF-α inhibitors, especially among patients receiving ADA.

Advances in biologic and small molecule therapies for hidradenitis suppurativa

INTRODUCTION

Hidradenitis suppurativa (HS) is a chronic, debilitating inflammatory skin disorder characterized by painful nodules, abscesses, fistulae, and scarring with a predilection for flexural regions. Several biologics and small molecule inhibitors are being evaluated in clinical trials for treatment.

AREAS COVERED

The authors discuss the data available from clinical trials and smaller, high-quality studies for existing and emerging biologic and small molecule inhibitor therapies for treatment of HS. Biologics discussed include TNFα, IL-17, IL-23, IL-12/23, and IL-1 inhibitors. Small molecule inhibitors discussed include PDE4, JAK, TYK, IFX-1, and complement cascade inhibitors. Pharmacokinetics and pharmacodynamics for these drugs are also described.

EXPERT OPINION

Trial data and our own experience have shown that about half of HS patients experience improvement with adalimumab. However, there is a significant need for pharmacotherapies with higher efficacy goals as in those used for psoriasis. Many biologics and small molecule inhibitors are being tested in clinical trials. The landscape of upcoming therapies for hidradenitis suppurativa appears promising.

Correlation Among Body Composition Parameters and Long-Term Outcomes in Crohn's Disease After Anti-TNF Therapy

Background

The impact of the body composition on the pathophysiology and clinical course of Crohn's disease (CD) has not been fully elucidated.

Aims

To reveal the correlations among body composition and long-term outcomes in CD after anti-TNF therapy.

Methods

Ninety-one patients who received anti-TNF therapy as their first biologic treatment were enrolled. The skeletal muscle index (SMI), visceral and subcutaneous fat area (VFA, SFA), and the ratio of the VFA to SFA (mesenteric fat index; MFI) at the 3^rd lumbar level were measured using computed tomography (CT) imaging before the induction. The correlation among the body composition and outcomes were retrospectively analyzed.

Results

The 5-year cumulative secondary failure- and resection-free rates in patients with a low SMI (39.1% and 64.8%) were significantly lower than those with a high SMI (67.5% and 92.7%; p = 0.0071 and 0.0022, respectively). The 5-year cumulative secondary failure-free rate in the patients with low VF (45.0%) was significantly lower than that in those with high VF (77.6%; p = 0.016), and the 5-year cumulative resection-free rate in patients with a high MFI (68.9%) was significantly lower than that in those with a low MFI (83.0%; p = 0.031). Additionally, patients with low age and BMI had significantly lower cumulative secondary failure- and resection-free rates than those with high age and BMI (low age: 37.4% and 71.2%; high age: 70.7% and 88.9%; p = 0.0083 and 0.027, respectively) (low BMI: 27.2% and 64.8%; high BMI: 68.3% and 87.9%; p = 0.014 and 0.030, respectively), respectively. In the multivariate analyses, a low SMI was the only independent risk factor for secondary failure (hazard ratio [HR] 2.15, 95% confidence interval [CI] 1.04–4.44), while low age (HR 4.06, 95% CI 1.07–15.4), a low SMI (HR 4.19, 95% CI 1.01–17.3) and high MFI were risk factors for bowel resection (HR 4.31, 95% CI 1.36–13.7).

Conclusion

The skeletal muscle mass and ratio of visceral to subcutaneous fat were suggested to reflect the long-term clinical outcome and may be helpful as prognostic markers after anti-TNF therapy in CD.

Therapeutic Drug Monitoring in Perianal Fistulizing Crohn’s Disease

Perianal fistulas are a common complication of Crohn’s disease (CD) that has, historically, been challenging to manage. Despite the strong available evidence that anti-tumor necrosis factor (anti-TNF) agents are useful in the treatment of perianal fistulizing Crohn’s disease (PFCD), a significant number of these patients do not respond to therapy. The use of therapeutic drug monitoring (TDM) in patients with CD receiving biologic agents has evolved and is currently positioned as an important tool to optimize and guide biologic treatment. Considering the treatment of PFCD can represent a challenge; identifying novel tools to improve the efficacy of current treatments is an important unmet need. Given its emerging role in other phenotypes of Crohn’s disease, the use of TDM could also offer an opportunity to enhance the effectiveness of available therapies and improve outcomes in the subset of patients with PFCD receiving biologics. Overall, there is mounting evidence that higher anti-TNF drug levels are associated with better rates of “fistula healing”. However, studies have been limited by their use of subjective outcomes and observational designs. Ultimately, further interventional, randomized controlled trials looking into the relationship between drug exposure and fistula outcomes are needed.

Delaying an infliximab infusion by more than 3 days is associated with a significant reduction in trough levels but not with clinical worsening

BACKGROUND

Higher infliximab trough levels (TLs) correlate with better clinical, inflammatory, and endoscopic outcomes among inflammatory bowel disease (IBD) patients. Although standard scheduled infliximab therapy regimen consists of infusions at pre-defined time-points (weeks 0, 2, 6, and every 8 weeks), short-period deviations from therapeutic schedule are common in 'real life', but the pharmacokinetic impact of these deviations has not been explored. In this study, we aim to determine whether short-period deviations from infusion schedule affect infliximab-TL.

METHODS

A retrospective analysis of all IBD patients receiving infliximab maintenance therapy every 8 weeks was conducted in a tertiary medical center. Patients with anti-drug antibodies, deliberate interval shortening and <3 sequential maintenance sera available were excluded. Associations between time since last infusion and TL were studied. Statistical analysis was performed using generalized estimating equations.

RESULTS

Out of over 10,000 sera, 2088 sera of 302 maintenance period stable infliximab-therapy-patients met inclusion criteria (median TL 4.1 μg/mL, interquartile range (IQR) 2.3-6.5 μg/mL). A delay beyond 3 days in infusion schedule (n > 59 days since last infusion) was found to significantly affect TL (mean difference in TL 0.9 μg/mL, 95% confidence interval (CI): 0.03-1.9 μg/mL, p < 0.04). Furthermore, among patients with delayed infusions, 80% had TL below 5 μg/mL, in comparison to 55% of patients who were not late (odds ratio (OR): 2.81, CI: 2.02-3.92, p < 0.0001).

CONCLUSION

Real-life delays of ⩽3 days from infusion protocol can probably be allowed. Delays >3 days culminate in measurable decrease of TL, although effect on clinical outcome is unclear. This needs to be taken into account when interpreting drug-level test results.

SUMMARY

A total of 2088 sera of 302 maintenance period inflammatory bowel disease (IBD) patients treated with infliximab were analyzed, to assess effect of small deviations from infusion schedule on TLs. A significant decline in patients' trough level (TL) was noted as early as 3 days after scheduled infusion.

Impact of Obesity on Inflammatory Bowel Disease

PURPOSE OF REVIEW

This review highlights recent work that evaluates the impact of obesity on inflammatory bowel disease (IBD) pathogenesis and management.

RECENT FINDINGS

The impact of obesity on IBD prevalence, clinical course, and management, has been studied and described more so in recent years. Studies have shown that obesity increases IBD disease activity, leads to longer hospitalization courses, and increases the likelihood of the development of extraintestinal manifestations. Recent evidence has also suggested that obese IBD patients have a higher frequency of extended steroid treatment and increased use of antibiotics compared to non-obese IBD patients. The effect of obesity on patients with IBD is a topic that has garnered widespread interest in the last decade due to the increasing prevalence of both diseases. To date however, although there are still many unanswered questions. It is quite clear that obesity, and more specifically, visceral adiposity, affects numerous IBD-related outcomes in regard to pathogenesis, extra-intestinal manifestations, response to medical and surgical therapies, hospital length of stay, healthcare-related costs, and health-related quality of life. Future studies should include larger patient populations and evaluate additional factors that are altered in those with obesity including the gut microbiome, dietary patterns, and whether weight loss and/or degree of weight loss impact clinical outcomes.

How to Choose the Biologic Therapy in a Bio-Naïve Patient with Inflammatory Bowel Disease

The availability of biologic therapies in inflammatory bowel disease (IBD) is increasing significantly. This represents more options to treat patients, but also more difficulties in choosing the therapies, especially in the context of bio-naïve patients. Most evidence of safety and efficacy came from clinical trials comparing biologics with placebo, with a lack of head-to-head studies. Network meta-analysis of biologics and real-world studies have been developed to solve this problem. Despite the results of these studies, there are also other important factors to consider before choosing the biologic, such as patient preferences, comorbidities, genetics, and inflammatory markers. Given that resources are limited, another important aspect is the cost of biologic therapy, since biosimilars are widely available and have been demonstrated to be effective with a significant decrease in costs. In this review, we summarize the evidence comparing biologic therapy in both Crohn´s disease (CD) and ulcerative colitis (UC) in different clinical situations. We also briefly synthesize the evidence related to predictors of biologic response, as well as the biologic use in extraintestinal manifestations and the importance of the drug-related costs.

A population physiologically-based pharmacokinetic model to characterize antibody disposition in pediatrics and evaluation of the model using infliximab

AIMS

In order to better predict the pharmacokinetics (PK) of antibodies in children, and to facilitate dose optimization of antibodies in paediatric patients, there is a need to develop systems PK models that integrate ontogeny-related changes in human physiological parameters.

METHODS

A population-based physiological-based PK (PBPK) model to characterize antibody PK in paediatrics has been developed, by incorporating age-related changes in body weight, organ weight, organ blood flow rate and interstitial volumes in a previously published platform model. The model was further used to perform Monte Carlo simulations to investigate clearance vs. age and dose-exposure relationships for infliximab.

RESULTS

By estimating only one parameter and associated interindividual variability, the model was able to characterize clinical PK of infliximab from two paediatric cohorts (n = 141, 4-19 years) reasonably well. Model simulations demonstrated that only 50% of children reached desired trough concentrations when receiving FDA-labelled dosing regimen for infliximab, suggesting that higher doses and/or more frequent dosing are needed to achieve target trough concentrations of this antibody.

CONCLUSION

The paediatric PBPK model presented here can serve as a framework to characterize the PK of antibodies in paediatric patients. The model can also be applied to other protein therapeutics to advance precision medicine paradigm and optimize antibody dosing regimens in children.

Utility, promise, and limitations of liquid chromatography-mass spectrometry-based therapeutic drug monitoring in precision medicine

Therapeutic drug monitoring (TDM) is typically referred to as the measurement of the concentration of drugs in patient blood. Although in the past, TDM was restricted to drugs with a narrow therapeutic range in order to avoid drug toxicity, TDM has recently become a major tool for precision medicine being applied to many more drugs. Through compensating for interindividual differences in a drug's pharmacokinetics, improved dosing of individual patients based on TDM ensures maximum drug effectiveness while minimizing side effects. This is especially relevant for individuals that present a particularly high intervariability in pharmacokinetics, such as newborns, or for critically/severely ill patients. In this article, we will review the applications for and limitations of TDM, discuss for which patients TDM is most beneficial and why, examine which techniques are being used for TDM, and demonstrate how mass spectrometry is increasingly becoming a reliable and convenient alternative for the TDM of different classes of drugs. We will also highlight the advances, challenges, and limitations of the existing repertoire of TDM methods and discuss future opportunities for TDM-based precision medicine.

Population pharmacokinetics of subcutaneous infliximab CT-P13 in Crohn's disease and ulcerative colitis

BACKGROUND

Infliximab is a chimeric monoclonal antibody against tumour necrosis factor-alpha for the treatment of Crohn's disease (CD) and ulcerative colitis (UC). Recently, a subcutaneous formulation of CT-P13, an infliximab biosimilar, was approved for clinical use.

AIMS

To characterise CT-P13 pharmacokinetics (PK) and its clinically relevant determinants after subcutaneous administration through population PK modelling.

METHODS

Data from a two-part Phase I study with intravenous (5 mg/kg) and variable maintenance subcutaneous dosing of CT-P13 with frequent PK sampling in patients with CD or UC were used. Population PK analysis was conducted by non-linear mixed effects modelling. Covariates affecting PK parameters were chosen based on their clinical relevance (effect size of ≥20%) using a full fixed-effect modelling approach.

RESULTS

CT-P13 PK was described by a two-compartment model with linear elimination. The half-life in a typical 70 kg patient with serum albumin of 44 g/L was 10.8 days. The typical value for clearance was 0.355 L/d, absorption constant 0.273/d, bioavailability 79.1%, central volume of distribution 3.10 L and peripheral volume of distribution 1.93 L. Clinically relevant covariates affecting clearance were body weight (+43.2% from 70 to 120 kg), the presence of anti-drug antibodies (+39%) and serum albumin concentration (+30.1% from 44 to 32 g/L). Simulated drug exposure was comparable between routes of administration for patients weighing 50 or 70 kg, but lower with subcutaneous dosing in patients weighing 120 kg.

CONCLUSIONS

This first population PK model for subcutaneous CT-P13 supports fixed subcutaneous maintenance dosing, although heavy patients had lower cumulative drug exposure.

A random forest model predicts responses to infliximab in Crohn's disease based on clinical and serological parameters

BACKGROUND

Infliximab (IFX) has revolutionised the treatment for Crohn's disease (CD) recently, while a part of patients show no response to it at the end of the induction period. We developed a random forest-based prediction tool to predict the response to IFX in CD patients.

METHODS

This observational study retrospectively enrolled the patients diagnosed with active CD and received IFX treatment at the Gastroenterology Department in Xiangya Hospital of Central South University between January 2017 and December 2019. The baseline data were recorded in the beginning and were used as predictor variables to construct models to forecast the outcome of the response to IFX.

RESULTS

Our cohort identified a total of 174 patients finally with a response rate of 29.3% (51/174). The area under the receiver operating characteristic curve (AUC) for the model, based on the random forest was 0.90 (95%CI: 0.82-0.98), compared to the logistic regression model with AUC of 0.68 (95%CI: 0.52-0.85). The optimal cut-off value of the random forest model was 0.34 with the specificity of 0.94, the sensitivity of 0.81 and the accuracy of 0.85. We demonstrated a strong association of IFX response with the levels of complement C3 (C3), high density lipoprotein, serum albumin, Controlling Nutritional Status (CONUT) score and visceral fat area/subcutaneous fat area ratio (VSR).

CONCLUSION

A novel random forest model using the clinical and serological parameters of baseline data was established to identify CD patients with baseline inflammation to achieve IFX response. This model could be valuable for physicians, patients and insurers, which allows individualised therapy.

External Model Performance Evaluation of Twelve Infliximab Population Pharmacokinetic Models in Patients with Inflammatory Bowel Disease

Infliximab is approved for treatment of various chronic inflammatory diseases including inflammatory bowel disease (IBD). However, high variability in infliximab trough levels has been associated with diverse response rates. Model-informed precision dosing (MIPD) with population pharmacokinetic models could help to individualize infliximab dosing regimens and improve therapy. The aim of this study was to evaluate the predictive performance of published infliximab population pharmacokinetic models for IBD patients with an external data set. The data set consisted of 105 IBD patients with 336 infliximab concentrations. Literature review identified 12 published models eligible for external evaluation. Model performance was evaluated with goodness-of-fit plots, prediction- and variability-corrected visual predictive checks (pvcVPCs) and quantitative measures. For anti-drug antibody (ADA)-negative patients, model accuracy decreased for predictions > 6 months, while bias did not increase. In general, predictions for patients developing ADA were less accurate for all models investigated. Two models with the highest classification accuracy identified necessary dose escalations (for trough concentrations < 5 µg/mL) in 88% of cases. In summary, population pharmacokinetic modeling can be used to individualize infliximab dosing and thereby help to prevent infliximab trough concentrations dropping below the target trough concentration. However, predictions of infliximab concentrations for patients developing ADA remain challenging.

External Evaluation of Population Pharmacokinetic Models and Bayes-Based Dosing of Infliximab

Despite the well-demonstrated efficacy of infliximab in inflammatory diseases, treatment failure remains frequent. Dose adjustment using Bayesian methods has shown in silico its interest in achieving target plasma concentrations. However, most of the published models have not been fully validated in accordance with the recommendations. This study aimed to submit these models to an external evaluation and verify their predictive capabilities. Eight models were selected for external evaluation, carried out on an independent database (409 concentrations from 157 patients). Each model was evaluated based on the following parameters: goodness-of-fit (comparison of predictions to observations), residual error model (population weighted residuals (PWRES), individual weighted residuals (IWRES), and normalized prediction distribution errors (NPDE)), and predictive performances (prediction-corrected visual predictive checks (pcVPC) and Bayesian simulations). The performances observed during this external evaluation varied greatly from one model to another. The eight evaluated models showed a significant bias in population predictions (from -7.19 to 7.38 mg/L). Individual predictions showed acceptable bias and precision for six of the eight models (mean error of -0.74 to -0.29 mg/L and mean percent error of -16.6 to -0.4%). Analysis of NPDE and pcVPC confirmed these results and revealed a problem with the inclusion of several covariates (weight, concomitant immunomodulatory treatment, presence of anti-drug antibodies). This external evaluation showed satisfactory results for some models, notably models A and B, and highlighted several prospects for improving the pharmacokinetic models of infliximab for clinical-biological application.

Impact of obesity on disease activity and disease outcome in inflammatory bowel disease: Results from the Swiss inflammatory bowel disease cohort

OBJECTIVE

The purpose of this study was to investigate the impact of obesity on disease activity and disease outcome in patients with inflammatory bowel disease.

PATIENTS AND METHODS

The impact of obesity on inflammatory bowel disease disease activity and outcome was retrospectively assessed in 3075 patients enrolled in the prospective nation-wide Swiss inflammatory bowel disease cohort between July 2006 and September 2018. Baseline characteristics, disease activity and disease course in 325 obese inflammatory bowel disease patients (body mass index ≥30 kg/m²) were compared to 1725 normal weight inflammatory bowel disease individuals (body mass index 18.5-24.9).

RESULTS

Among 3075 patients in the prospective Swiss inflammatory bowel disease cohort, 325 patients (10.6%) were obese, namely, 194 Crohn's disease patients, 131 ulcerative colitis, and inflammatory bowel disease-unclassified patients. Disease activity scores were elevated in obese Crohn's disease (Crohn's Disease Activity Index 33 vs 20, p = 0.001), but not ulcerative colitis patients. Obese Crohn's disease, but not ulcerative colitis patients were less likely to be in remission based on a Crohn's Disease Activity Index less than 100 and a calprotectin less than 100 ug/g. In a multivariate regression model, obesity was negatively associated with disease remission in Crohn's disease (odds ratio 0.610, 95% confidence interval 0.402-0.926, p = 0.020), but not ulcerative colitis. Increased soft stool frequency was observed in both obese Crohn's disease and ulcerative colitis patients. Adjusted Cox regression models revealed increased risk of complicated disease course in obese Crohn's disease patients (hazard ratio 1.197, 95% confidence interval 1.046-1.370, p = 0.009). No association between obesity and disease progression, index treatment failure was seen neither in Crohn's disease nor ulcerative colitis.

CONCLUSION

Obesity is associated with decreased rates of disease remission and increased risk of complicated disease course in Crohn's disease over a six-year follow-up period. No effects were seen on disease progression and index treatment failure neither in Crohn's disease nor ulcerative colitis.

Importance and Considerations of Antibody Engineering in Antibody-Drug Conjugates Development from a Clinical Pharmacologist's Perspective

Antibody-drug conjugates (ADCs) appear to be in a developmental boom, with five FDA approvals in the last two years and a projected market value of over $4 billion by 2024. Major advancements in the engineering of these novel cytotoxic drug carriers have provided a few early success stories. Although the use of these immunoconjugate agents are still in their infancy, valuable lessons in the engineering of these agents have been learned from both preclinical and clinical failures. It is essential to appreciate how the various mechanisms used to engineer changes in ADCs can alter the complex pharmacology of these agents and allow the ADCs to navigate the modern-day therapeutic challenges within oncology. This review provides a global overview of ADC characteristics which can be engineered to alter the interaction with the immune system, pharmacokinetic and pharmacodynamic profiles, and therapeutic index of ADCs. In addition, this review will highlight some of the engineering approaches being explored in the creation of the next generation of ADCs.