Higher Infliximab Trough Levels Are Associated With Better Outcome in Paediatric Patients With Inflammatory Bowel Disease

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.

Clinical Validation of a Capillary Blood Home-Based Self-Sampling Technique for Monitoring of Infliximab, Vedolizumab, and C-Reactive Protein Concentrations in Patients With Inflammatory Bowel Disease

BACKGROUND

Therapeutic drug monitoring provides important guidance for treatment of patients with inflammatory bowel disease (IBD) and could help to early identify treatment failure. This study aimed to validate a finger prick-based capillary blood sampling technique to measure biological trough levels and C-reactive protein (CRP) and evaluate patient performance and -support.

METHODS

In this prospective cohort study, patients with IBD receiving infliximab (IFX) or vedolizumab (VEDO) therapy performed finger prick-based capillary blood sampling at home. Additionally, blood was collected through routinely performed in-hospital venepuncture prior to biological infusion. IFX, VEDO, and CRP concentrations were measured by enzyme-linked immunosorbent assay. The concordance between methods was statistically evaluated and a survey was conducted to assess practicality and patient support.

RESULTS

In total, 81 patients (46 IFX, 35 VEDO) were enrolled. Mean differences between both methods were 0.42 (95% confidence interval, -1.74 to 2.58) μg/mL for IFX and 0.72 (95% confidence interval, -5.50 to 6.94) μg/mL for VEDO. Passing-Bablok regressions demonstrated no evidence for systematic or proportional biases. Venous and capillary IFX (ρ = 0.96, P < .001) and VEDO (ρ = 0.97, P < .001) levels strongly correlated and showed high intermethod agreement (Cohen's kappa: IFX = 0.82; VEDO = 0.94). Similarly, venous and capillary CRP levels were strongly correlated (ρ = 0.99, P < .001). Most patients (>95%) were able to successfully perform the self-sampling at home without prior instructions.

CONCLUSIONS

This study clinically validated a finger prick-based capillary blood self-sampling technique allowing concomitant home monitoring of biological levels and CRP for patients with IBD, who reported substantial support, tolerability, and practicality.

Factors that influence infliximab biosimilar trough levels in the pediatric inflammatory bowel disease population

BACKGROUND

The pharmacokinetics and pharmacodynamics of biosimilar infliximab (IFX-BioS) in pediatric inflammatory bowel disease (IBD) are poorly investigated. The aim of this study was to investigate factors predicting IFX-BioS trough levels (TLs).

RESEARCH DESIGN AND METHODS

IBD children with an indication to start IFX-BioS were included in this prospective observational study (January 2021-June 2022). TLs were measured at the 4th and 6th infusions and correlated with several covariates.

RESULTS

A total of 110 TLs in 55 children were included. The multivariate linear regression model at the 4th infusion found a positive correlation between TLs and age at diagnosis (B:1.950, 95% CI: [0.019, 3.882], p = 0.048) and IFX-BioS dose/kg (B:1.962, 95% CI: [0.238, 3.687], p = 0.029), and a negative correlation with clinical scores (B:-0.401, 95% CI: [-0.738, -0.064], p = 0.023). At the 6th infusion, female gender (B:6.887, 95% CI: [0.861, 12.913], p = 0.029), hemoglobin (B:1.853, 95% CI: [0.501, 3.204], p = 0.011), and IFX-BioS dose/kg (B:1.792, 95% CI: [0.979, 2.605], p < 0.001) were found to be positively correlated to TLs. No association between combined clinical and biochemical remission and TLs was found.

CONCLUSIONS

This study discovered some predictors for IFX-BioS TLs in IBD children. Knowledge of predictive factors could help physicians choose the best dosing regimen.

Infliximab Monotherapy vs Combination Therapy for Pediatric Crohn's Disease Exhibit Similar Pharmacokinetics

BACKGROUND

The use of concomitant azathioprine may improve efficacy and pharmacokinetic (PK) properties of infliximab (IFX) but is also associated with an increased risk of adverse events. Proactive therapeutic drug monitoring (pTDM) of IFX monotherapy is an alternative strategy to improve PK. The aim of this study was to evaluate whether IFX with an immunomodulator (combo) has PK benefits over IFX-pTDM (mono) in pediatric Crohn's disease (CD).

METHODS

This PK analysis included pediatric CD patients who started either IFX combo (TISKids study) or IFX mono with pTDM (REFINE cohort). Combo and mono IFX trough levels (TLs) and antibodies-to-infliximab were assessed at infusion 3, 4, and 5. A population PK model was built to compare IFX PK outcomes (clearance [CL], TLs and cumulative exposure) between combo and mono groups at infusion 4 and 5. Clinical response and steroid-free clinical remission (SFCR) was assessed at infusion 4 and 5.

RESULTS

This study included 128 pediatric CD patients (66 mono and 62 combo). At infusion 5, there was no significant difference between mono and combo median TLs 4.1 µg/mL (2.1, 7.8) vs 5.9 µg/mL (3.2, 9.4; P = .14) or median CL 0.26 L/d (0.21, 0.32) vs 0.26 L/d (0.21, 0.33; P = .81). Mono patients had a lower SFCR rate at infusion 5 (53% [31 of 59] vs 80% [32 of 40]; P = .01). Clinical response rates were significantly higher among combo than mono patients at both infusion 4 and 5.

CONCLUSIONS

This study suggests that there are no PK differences (TLs and CL) between combo and mono therapy in pediatric CD patients who started IFX.

Identifying risk factors of anti-TNF induced skin lesions and other adverse events in paediatric patients with inflammatory bowel disease

OBJECTIVES

While higher infliximab (IFX) trough concentrations (TCs) are associated with better outcomes in patients with inflammatory bowel disease (IBD), they could pose a risk for adverse events (AEs), including IFX-induced skin lesions. Therefore, we studied correlations between IFX TCs and occurrence of AEs in paediatric IBD patients.

METHODS

In this single-centre study, all children with Crohn's disease (CD) and ulcerative colitis (UC) receiving IFX maintenance therapy who underwent proactive drug monitoring between March 2015 and August 2022 were included. IFX doses/intervals/TCs and patient characteristics were systematically registered, as well as AEs and skin lesions appearance.

RESULTS

A total of 109 patients (72 CD and 37 UC) contributed 2913 IFX TCs. During a median follow-up of 3.0 [1.5-4.5] years, we observed 684 AEs in 101 patients and 49 skin lesions in 35 patients. There was no significant difference (p = .467) in median TCs between patients with and without skin lesions. However, higher median IFX doses were associated with an increased hazard rate of skin lesions [HR 1.084 (1.024-1.148), p = .005], in addition to female sex [2.210 (1.187-5.310), p = .016] and diagnosis of CD [1.695 (1.241-1.877), p = .011]. Considering IFX therapeutic TC cut-offs of 5.0 and 9.0 µg/mL, there was no significant difference in AE rate (p = .749 and p = .833, respectively). Also, no significant association between IFX doses and AE rate (p = .159).

CONCLUSIONS

Increasing the IFX dose to achieve therapeutic TCs may not increase the overall risk of AEs in paediatric IBD patients. However, concerns arise regarding the risk of skin lesions, especially in female CD patients.

Early infliximab trough levels in paediatric IBD patients predict sustained remission

Background

Exposure-response studies have shown that higher infliximab concentrations are associated with better outcomes in inflammatory bowel disease. There is little agreement about the optimal time to measure infliximab levels in children.

Objectives

We aimed to evaluate whether trough levels at week 6 or week 14 predict sustained remission. The secondary aim was to define target trough levels at weeks 6 and 14.

Design

We used routinely collected electronic healthcare data of 70 anti-tumour necrosis factor naïve children with inflammatory bowel disease treated with a standard infliximab induction- and variable maintenance scheme.

Methods

Trough levels and blood and faecal markers for disease activity were measured before every infliximab administration. Sustained remission was defined as the absence of symptoms and low inflammatory markers between weeks 26 and 52 after the start of infliximab therapy. Optimal infliximab levels at weeks 6 and 14 were determined using the receiver operating characteristic curve.

Results

The median infliximab level at week 6 was not significantly higher in children who achieved sustained remission compared to those who did not (16.9 mg/L versus 12.0 mg/L; p = 0.058) but the median infliximab level at week 14 was significantly higher in those with sustained remission (7.7 mg/L versus 3.8 mg/L; p = 0.006). The area under the receiver operating characteristics curves at weeks 6 and 14 to predict sustained remission was 0.67 (95% CI 0.51-0.83) and 0.75 (95% CI 0.60-0.90), respectively. Target trough levels at weeks 6 and 14 were ⩾13.2 and ⩾6.9 mg/L, respectively.

Conclusion

An infliximab measurement at week 14 with a target through level ⩾6.9 mg/L best predicted sustained remission.

Correlation between Treatment Outcomes and Serum Vitamin D Levels As Well As Infliximab Trough Concentration among Chinese Patients with Crohn's Disease

Background

The relationship between vitamin D (vit-D) levels and the effectiveness of infliximab (IFX) in patients with Crohn's disease (CD) remains controversial.

Objective

To evaluate the interaction between vit-D levels and the response to IFX therapy in patients with CD.

Methods

This was a retrospective cohort study. Serum vit-D and IFX trough concentrations (TC) were measured in 84 patients, and statistical analyses were performed.

Results

The total vit-D deficiency rate at enrollment, at week 14 and week 38, was 64.3%, 41.67%, and 37.5%, respectively (P < 0.001). CD activity index (CDAI) (120, range, 93-142.75) and simplified endoscopic activity score for CD (SES-CD) (2, range, 0-4) at week 14 were lower than that of enrollment (CDAI, 136.5, range, 101.25-196; SES-CD 13, range, 5-23) (P < 0.001). The biochemical remission (BR), clinical remission (CR), endoscopic remission (ER), and response (ERe) rates of week 38 were 76.1%, 88.5%, 22.4%, and 67.2%, respectively. vit-D levels at enrollment were positively correlated with CDAI at week 38 (P = 0.024). IFX serum TC was related to BR (P = 0.036), CR (P = 0.032) at week 14, and ERe (P = 0.009) at week 38.

Conclusion

Among Chinese patients with CD, vit-D levels prior to IFX therapy are related to CDAI scores, and IFX serum TC is associated with BR, CR, and ERe.

Anti-TNF Agents and New Biological Agents (Vedolizumab and Ustekinumab) in the Prevention and Treatment of Postoperative Recurrence After Surgery in Crohn's Disease

Surgery for Crohn's disease (CD) is not curative, as postoperative recurrence (POR) after ileocolonic resection is the rule in the absence of prophylactic treatment. In the present article, we critically review available data on the role of anti-tumour necrosis factor (TNF) agents and new biologics (including vedolizumab and ustekinumab) in the prevention and treatment of POR after surgery in CD. Several studies (summarised in various meta-analyses) have confirmed the efficacy of anti-TNFs in the prevention of POR. We identified 37 studies, including 1863 CD patients, with mean endoscopic POR at 6-12 months of 29%. Only few randomised controlled trials (RCTs) have directly compared thiopurines and anti-TNFs, with controversial results, although the superiority of the latter is supported by several meta-analyses. Infliximab and adalimumab seem equally effective. The combination of anti-TNFs and immunosuppressives should be considered in patients previously exposed to anti-TNFs. Several studies have shown that anti-TNFs remain an effective option to prevent POR also in patients with anti-TNF failure before surgery. In fact, the use of the same anti-TNF before and after surgery might be effective for the prevention of POR. Prophylactic anti-TNF treatment, once started, should be continued long term. Anti-TNFs are also effective for the treatment of established POR. Retreatment with anti-TNFs for POR is a valid strategy even after their preoperative failure. In six studies (including 156 patients) evaluating vedolizumab, mean endoscopic POR at 6-12 months was 41%. The non-randomised comparison of anti-TNFs and vedolizumab has provided controversial results. One placebo-controlled RCT confirmed that vedolizumab is quite effective in preventing POR in CD patients with increased risk of recurrence. Seven studies (including 162 patients) evaluated ustekinumab, with a mean endoscopic POR at 6-12 months of 41%. The comparative efficacy of ustekinumab and anti-TNFs is still unclear. Ustekinumab and vedolizumab seem to be equally effective, although the experience is very limited. In conclusion, to date, anti-TNFs are the most effective agents in preventing and treating POR in CD. Anti-TNFs remain an effective option to prevent POR also in patients with anti-TNF failure before surgery. Vedolizumab seems to be quite effective in the prevention of POR in patients with increased risk of recurrence. Ustekinumab is probably also effective in the postoperative setting, although the comparative efficacy with anti-TNFs or vedolizumab is still unclear.

Managing pediatric Crohn's disease: recent insights

INTRODUCTION

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

AREAS COVERED

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

EXPERT OPINION

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

Comparison of the Pharmacokinetics of CT-P13 Between Crohn's Disease and Ulcerative Colitis

BACKGROUND

We aimed to compare trough infliximab levels and the development of antidrug antibody (ADA) for 1 year between Crohn's disease (CD) and ulcerative colitis (UC) patients who were biologic-naive, and to evaluate their impact on clinical outcomes.

METHODS

This was a prospective, multicenter, observational study. Biologic-naive patients with moderate to severe CD or UC who started CT-P13, an infliximab biosimilar, therapy were enrolled. Trough drug and ADA levels were measured periodically for 1 year after CT-P13 initiation.

RESULTS

A total of 267 patients who received CT-P13 treatment were included (CD 168, UC 99). The rates of clinical remission (72% vs. 32.3%, P <0.001) at week 54 were significantly higher in CD than in UC. The median trough drug level (μg/mL) was significantly higher in CD than in UC up to week 14 (week 2, 18.7 vs. 14.7, P <0.001; week 6, 12.5 vs. 8.6, P <0.001; week 14, 3.4 vs. 2.5, P =0.001). The median ADA level (AU/mL) was significantly lower in CD than in UC at week 2 (6.3 vs. 6.5, P =0.046), week 30 (7.9 vs. 11.8, P =0.007), and week 54 (9.3 vs. 12.3, P =0.032). Development of ADA at week 2 [adjusted odds ratio (aOR)=0.15, P =0.026], initial C-reactive protein level (aOR=0.87, P =0.032), and CD over UC (aOR=1.92, P <0.001) were independent predictors of clinical remission at week 54.

CONCLUSION

Infliximab shows more favorable pharmacokinetics, including high drug trough and low ADA levels, in CD than in UC, which might result in better clinical outcomes for 1-year infliximab treatment in CD patients.

[Association between drug trough concentration and disease outcome before infliximab maintenance treatment in children with Crohn's disease]

OBJECTIVES

To study the association between infliximab trough level (IFX-TL) prior to maintenance treatment and disease outcome in children with Crohn's disease (CD).

METHODS

A retrospective analysis was performed on 35 children with CD who received induction therapy with infliximab (IFX) and the measurement of IFX-TL before maintenance treatment from August 2018 to November 2021. Clinical data and laboratory markers at baseline and before maintenance treatment were collected, and the association between outcome and IFX-TL was analyzed.

RESULTS

The clinical remission group, endoscopic remission group, and combined remission group had a significantly higher IFX-TL level than the corresponding non-remission groups (P<0.05), and there was no significant difference in the IFX-TL level between the biological remission and non-biological remission groups (P>0.05). The receiver operating characteristic (ROC) curve showed that IFX-TL had an area under the ROC curve of 0.959 (95%CI: 0.894-1) in predicting clinical remission, with a sensitivity of 90% and a specificity of 100% at the optimal cutoff value of 2.3 µg/mL (P<0.001).

CONCLUSIONS

Among children with CD receiving infliximab induction therapy, the children achieving clinical and endoscopic remission before maintenance treatment tend to have a higher level of IFX-TL. IFX-TL has a certain predictive value for clinical remission.

Optimized Infliximab Induction Predicts Better Long-Term Clinical and Biomarker Outcomes Compared to Standard Induction Dosing

OBJECTIVES

To evaluate the efficacy of standard and optimized infliximab induction dosing in attaining corticosteroid (CS) free clinical remission at week 52 and the effect that post-induction trough levels have on long-term outcome.

METHODS

Inflammatory bowel disease (IBD) patients ≤18 years commenced on infliximab between August 1, 2016, and August 1, 2018, from Vancouver, Canada, and Glasgow, Scotland, were included. The Glasgow cohort followed standard induction while the Vancouver cohort undertook induction optimization based on clinical, biomarker, and proactive infliximab trough levels. Baseline characteristics and laboratory values were documented.

RESULTS

In total, 140 children were included [median age 14.1 years (interquartile range (IQR) 12.0-16.0)]; 54% male. CS-free clinical remission at week 52 was higher in the optimized group compared to the standard cohort [65/78 (83%) vs. 32/62 (52%), P < 0.001]. Combined CS-free clinical and biomarker remission (CRP < 5 mg/L) was also higher in the optimized compared to the standard cohort [65/78 (83%) vs 25/62 (40%), P < 0.001]. The median post-induction trough level was higher in children who were in CS-free clinical remission at week 52 [3.6 mg/L (1.5-7.1)] vs. those who were not [2.0 mg/L (0.8-4.1), P = 0.04]. The odds of attaining a therapeutic post-induction trough level were almost 4-fold higher in the optimized group than the standard cohort (OR 3.97, 95% CI: 1.89-8.68, P < 0.001).

CONCLUSIONS

Standard infliximab induction resulted in less favorable long-term outcomes for pediatric IBD patients. Optimizing induction using clinical, biomarker, and proactive trough levels resulted in higher post-induction trough levels and a greater odds of attaining long-term clinical remission.

Updates in therapeutic drug monitoring in inflammatory bowel disease

Biologics and immunomodulators (IMM) are generally considered the most effective therapies for the treatment of ulcerative colitis and Crohn’s disease. However, despite the efficacy of these therapies, many patients either have a primary lack of response or a secondary loss of response to these medications. Therapeutic drug monitoring (TDM) is a systematic approach to managing such patients. In this review, we summarize the latest data on TDM, including reactive and proactive TDM, in patients with inflammatory bowel disease on biologics and/or IMM.

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.

Cost-Effectiveness of Therapeutic Drug Monitoring of Anti-TNF Therapy in Inflammatory Bowel Disease: A Systematic Review

Infliximab and adalimumab are monoclonal antibodies against tumor necrosis factor (anti-TNF) used to manage inflammatory bowel disease (IBD). Therapeutic Drug Monitoring (TDM) has been proven to prevent immunogenicity, to achieve better long-term clinical results and to save costs in IBD treatment. The aim of this study was to conduct a systematic review on cost-effectiveness analyses of studies that apply TDM of anti-TNF in IBD and to provide a critical analysis of the best scientific knowledge available in the literature. The quality of the included studies was assessed using Consolidated Health Economic Evaluation Reporting Standards (CHEERS). Cost-effectiveness of the TDM strategies was presented as total costs, cost savings, quality-adjusted life-years (QALY) and incremental cost-effectiveness ratio (ICER). Thirteen studies that examined the health economics of TDM of anti-TNF in IBD from 2013 to 2021 were included. Eight of them (61.5%) achieved a score between 17 and 23 on the CHEERS checklist. The comparison between the TDM strategy and an empirical strategy was cost saving. The ICER between reactive TDM and an empirical strategy was dominated (favorable) by reactive TDM, whereas the ICER value for proactive TDM compared to an empirical strategy ranged from EUR 56,845 to 3,901,554. This systematic review demonstrated that a TDM strategy is cost-effective or cost-saving in IBD.

Ultra-proactive Therapeutic Drug Monitoring of Infliximab Based on Point of Care Testing in Inflammatory Bowel Disease: Results of a Pragmatic Trial

BACKGROUND

With point of care testing [POCT] for infliximab [IFX], ultraproactive therapeutic drug monitoring [TDM] with ad-hoc dose optimisation is possible in patients with inflammatory bowel disease [IBD].

AIM

To compare the clinical outcomes of an ultraproactive TDM algorithm of IFX based on POCT with reactive TDM in patients with IBD, in a pragmatic clinical trial.

METHODS

All patients with IBD and maintenance IFX treatment were included between June and August 2018 in two centres. Centre A applied an ultra-proactive TDM algorithm incorporating POCT, and centre B applied reactive TDM. Primary endpoint was failure of IFX therapy after 1 year. Secondary endpoints included sustained clinical remission and mucosal remission.

RESULTS

In total 187 patients [n = 115/72 cohort A/B] were included. Cohort A had more trough level [TL] measurements compared with cohort B [8.8 vs 1/patient/year; p <0.0001], leading to a significant higher number of dose optimisations. POCT testing was required in 27% after the first round of ultra-proactive TDM and in a mean of 6.3% (standard deviation [SD] 1.9) in the subsequent rounds. Ad-hoc extra dosing was needed in 13% of the POCT. After 1 year, no difference was seen between cohort A and cohort B in IFX failure [19% vs 10%; p = 0.08], nor in sustained clinical remission [75% vs 83%; p = 0.17]. Mucosal remission was evaluated in 71 patients [38%], and was more frequent in the reactive TDM cohort [p = 0.02].

CONCLUSIONS

Ultra-proactive TDM in patients with IBD and maintenance IFX treatment leads to equal clinical outcomes as reactive TDM after 1 year of follow-up.

Infliximab Concentrations during Induction Are Predictive for Endoscopic Remission in Pediatric Patients with Inflammatory Bowel Disease under Combination Therapy

OBJECTIVES

To study infliximab (IFX) pharmacokinetics in children with inflammatory bowel disease (IBD) during induction therapy to predict outcome and explore if other covariates influenced outcome.

STUDY DESIGN

All children with IBD starting IFX therapy (5 mg/kg at weeks 0, 2, 6, and 12) for active luminal disease from May 2017 to May 2019 were included and followed prospectively. Patients were sampled at multiple timepoints during induction (trough concentrations and peak concentration at weeks 0, 2, 6, and 12, and intermediate concentration at weeks 1-4). IFX concentrations and cumulative drug exposure were correlated with outcome at 6 months. Endoscopic remission was defined as Simple Endoscopic Score for Crohn's Disease of <3 or Mayo endoscopic subscore of 0, and deep remission as endoscopic with clinical remission (Pediatric Ulcerative Colitis Activity Index/Pediatric Crohn's Disease Activity Index of <10).

RESULTS

There were 252 serum induction concentrations obtained from 32 patients (81% on concomitant thiopurines). Children in endoscopic remission (all in deep remission) at 6 months had significantly higher drug concentrations from week 4 onward. A receiver operating characteristics curve analysis identified IFX trough concentrations at week 12 of ≥5.0 μg/mL and area under the curve at weeks 0-12 of ≥4056.0 μg∗day/mL as the minimal target to achieve endoscopic remission at 6 months (area under the receiver operating characteristics curve, 0.796 [95% CI, 0.62-0.97] and area under the receiver operating characteristics curve, 0.778 [95% CI, 0.61-0.94], respectively). In addition, our findings suggest that proteomic analysis may help to understand IFX response.

CONCLUSIONS

Higher IFX exposure during induction therapy in pediatric patients with IBD is associated with significantly better endoscopic and deep remission rates at 6 months. Drug concentrations differentiate remitters from nonremitters from week 4 after induction onward.

Biomarkers for Optimization and Personalization of Anti-TNFs in Pediatric Inflammatory Bowel Disease

The use of biological drugs has improved outcomes in pediatric inflammatory bowel disease (IBD). Prediction of the response to biological drugs would be extremely useful in IBD, and even more so in children, who are still growing physically and psychologically. Specific clinical, biochemical, and genetic parameters are considered predictive of response to biological drugs, although few studies have been carried out in children with IBD. In this review, we present current evidence on biological treatments used in pediatric IBD and the available biomarkers of response. We examine demographics, clinical characteristics, biomarkers (genetic, genomic, and cellular), and microbiota.

CORRELATION BETWEEN TROUGH LEVELS OF INFLIXIMAB AND POSTOPERATIVE ENDOSCOPIC RECURRENCE IN CROHN'S DISEASE PATIENTS SUBMITTED TO ILEOCOLONIC RESECTIONS: A SYSTEMATIC REVIEW

BACKGROUND

The rates of postoperative endoscopic recurrence (PER) in patients with Crohn's disease (CD) are consistent. Anti-TNF therapy has been increasingly used in the postoperative setting, despite the lack of robust data in the literature on the measurement of trough levels and consequences of their use.

OBJECTIVE

The aim of this review was to assess trough levels of infliximab (IFX) in CD patients after ileocolonic resections in correlation with the presence of PER.

METHODS

We searched for studies that evaluated trough levels of IFX in patients with CD, who underwent ileocaecal resections, and correlated them with the presence of PER. We used MEDLINE through PubMed and CENTRAL Cochrane library databases, and after matching the inclusion criteria, the studies were methodologically evaluated with qualitative analysis of the data.

RESULTS

A total of 155 studies were initially identified in the databases search and only four matched the inclusion criteria. They comprised one prospective cohort study, one randomized controlled trial and two retrospective cohort studies, the last one performed in pediatric patients. This evidence suggested the correlation of PER with low trough levels of IFX and the presence of antibodies to the drug. The quality of the evidence generated varied from very low to high, due to the heterogeneity found between the studies and the risks of bias that were identified.

CONCLUSION

Low levels of IFX and the presence of antibodies to the drug were directly associated with increased PER rates in patients with CD, who underwent ileocolonic resections. Controlled and randomized clinical trials with adequate methodological quality are warranted to confirm the conclusions from this systematic review.

Is It Useful to Monitor Thiopurine Metabolites in Pediatric Patients with Crohn's Disease on Combination Therapy? A Multicenter Prospective Observational Study

BACKGROUND

The additional value of azathioprine concomitant treatment on infliximab pharmacokinetics in children is not well described yet.

AIMS

In the present study, we aimed to describe the relationship between thiopurine metabolite levels, infliximab trough levels, anti-IFX antibody formation, and clinical and laboratory markers of disease activity in pediatric patients with Crohn's disease, and to assess non-adherence.

METHODS

Data were collected prospectively during repeated visits from pediatric patients followed for Crohn's disease in two Czech pediatric inflammatory bowel disease centers between January 2016 and June 2017. Thiopurine metabolites (6-thioguanine and 6-methylmercaptopurine) were measured by high-performance liquid chromatography. Infliximab trough levels and anti-IFX antibody serum levels were measured routinely by ELISA. The risk of loss of response to infliximab therapy was also assessed.

RESULTS

A significant association between infliximab serum levels and 6-thioguanine erythrocyte levels was observed when tested as categorical variables (63 patients, 321 observations). To predict infliximab levels > 5 µg/mL, we propose a 6-thioguanine cutoff of 278 pmol/8 × 10⁸ erythrocytes (sensitivity, 0.799; specificity, 0.347). A higher loss-of-response-to-infliximab rate (tested in a subgroup of 51 patients) was observed in patients with undetectable 6-thioguanine levels than in those with detectable levels (p = 0.026). Non-adherence to azathioprine therapy was suspected in 20% of patients.

CONCLUSION

Thiopurine metabolite monitoring in pediatric patients with Crohn's disease is useful when optimizing combination therapy. Pediatric patients with undetectable 6-thioguanine levels are more likely to lose response to infliximab therapy. When targeting optimal infliximab levels, the 6-thioguanine cutoff levels in children appear to be higher than in adults.

Impact of infliximab therapeutic drug level monitoring on outcomes of patients with inflammatory bowel disease: A real-world experience from a Middle Eastern cohort

BACKGROUND AND STUDY AIM

Therapeutic drug monitoring (TDM) through measurement of infliximab (IFX) trough levels and antibodies to infliximab (ATI) is performed to guide IFX intensification strategies and improve its efficacy. We conducted this study to explore the relationship between clinical and endoscopic/radiological remission and IFX and ATI levels in patients with inflammatory bowel disease (IBD) treated with IFX and to evaluate the appropriateness of treatment decision post TDM.

PATIENTS AND METHODS

This was a cross-sectional study of a cohort of adult patients with IBD. Serum IFX trough concentrations and ATI were measured.

RESULTS

A total of 129 patients [104] with ulcerative colitis (UC) and 25 with Crohn's disease (CD)] were included in this study, of whom 61.2% were men. The mean disease duration was 6.7 years, and 72% of patients with UC had extensive colitis. The mean serum IFX trough level was 4.1 µg/mL; the IFX trough levels were subtherapeutic in 75 patients (58%), therapeutic in 37 patients (29%), and supratherapeutic in 17 patients (13%). Positivity to ATI was found in 16 patients (12.4%). Only 43 patients (33.3%) underwent an appropriate change in therapy after TDM, patients with penetrating CD disease had low IFX levels and higher C-reactive protein levels at 12 months before TDM.

CONCLUSIONS

Patients with IBD with therapeutic IFX levels tend to have increased endoscopic/radiological remission rates. However, an appropriate change in management based on TDM was absent in the majority of patients, potentially reflecting the need to have a dashboard to support and guide clinicians in decision-making.

Personalized Medicine of Monoclonal Antibodies in Inflammatory Bowel Disease: Pharmacogenetics, Therapeutic Drug Monitoring, and Beyond

The pharmacotherapy of inflammatory bowel diseases (Crohn’s disease and ulcerative colitis) has experienced significant progress with the advent of monoclonal antibodies (mABs). As therapeutic proteins, mABs display peculiar pharmacokinetic characteristics that differentiate them from chemical drugs, such as aminosalicylates, antimetabolites (i.e., azathioprine, 6-mercaptopurine, and methotrexate), and immunosuppressants (corticosteroids and cyclosporine). However, clinical trials have demonstrated that biologic agents may suffer from a pharmacokinetic variability that could influence the desired clinical outcome, beyond primary resistance phenomena. Therefore, therapeutic drug monitoring (TDM) protocols have been elaborated and applied to adaptation drug doses according to the desired plasma concentrations of mABs. This activity is aimed at maximizing the beneficial effects of mABs while sparing patients from toxicities. However, some aspects of TDM are still under discussion, including time-changing therapeutic ranges, proactive and reactive approaches, the performance and availability of instrumental platforms, the widely varying individual characteristics of patients, the severity of the disease, and the coadministration of immunomodulatory drugs. Facing these issues, personalized medicine in IBD may benefit from a combined approach, made by TDM protocols and pharmacogenetic analyses in a timeline that necessarily considers the frailty of patients, the chronic administration of drugs, and the possible worsening of the disease. Therefore, the present review presents and discusses the activities of TDM protocols using mABs in light of the most recent results, with special attention on the integration of other actions aimed at exploiting the most effective and safe therapeutic effects of drugs prescribed in IBD patients.

Infliximab Level Between Venous and Capillary Blood Using Novel Device Strongly Correlate in Paediatric Inflammatory Bowel Disease Patients

OBJECTIVES

Blood to measure infliximab (IFX) levels is typically obtained with venipuncture. Dried blood sampling (DBS), using capillary blood obtained from a finger prick, would be an alternative to measure IFX blood levels while being more patient friendly. The aim of this study is to compare IFX blood level measured by venipuncture versus DBS in patients with paediatric inflammatory bowel disease (PIBD) to assure accuracy.

METHODS

A prospective clinical pilot study was performed in patients with PIBD. Before IFX infusion, blood was collected simultaneously through venipuncture and DBS from a finger prick, using Mitratips (Neoteryx). All IFX concentrations were measured by an enzyme-linked immunosorbent assay. The Bland-Altman analysis was used to measure limits of agreement. The interrater reliability was measured with the interclass correlation coefficient and Cohen kappa. To calculate Cohen kappa, IFX levels were categorized into 3 groups; low <5 μg/mL, adequate 5 to 10 μg/mL, and high >10 μg/mL.

RESULTS

Twenty patients were included. Median age was 12.1 year (interquartile range 8-16 year). The mean difference between the 2 methods was -0.14 as calculated with Bland-Altman plot. The limits of agreement were between -1.39 and 1.12. The interclass correlation coefficient was with 0.998 excellent. The Cohen kappa between 3 IFX level categories was strong K = 0.911 (P = 0.0001). There was a strong correlation between venous IFX serum levels and DBS (r = 0.991, P = 0.0001) in the included patients.

CONCLUSIONS

This is the first study in patients with PIBD to show that bloodspot technology is a patient friendly alternative method to measure IFX blood levels in PIBD.

Is there a correlation between infliximab trough levels and the development of adverse events in patients with inflammatory bowel disease?

BACKGROUND/AIMS

The measurement of infliximab trough levels (IFX-TLs) in patients with inflammatory bowel disease (IBD) is performed to optimize treatment. However, the association between the development of adverse events (AEs) and IFX-TLs has not been sufficiently studied thus far. To investigate the possible association of IFX-TLs with AEs in Greek patients with IBD receiving maintenance treatment with IFX.

METHODS

A retrospective analysis of the registry data of the Gastroenterology Department of the University Hospital of Heraklion, from IBD patients with at least one available IFX-TL measurement during the years 2016 to 2017 was conducted. AEs reported 4 months before and 4 months after the measured IFX-TLs were recorded. The IFX-TLs of patients with or without AEs were compared.

RESULTS

Of a total of 83 IBD patients (61 Crohn's disease [73%]; 52 men [63%]; mean age ± standard deviation, 43.3 ± 16.0 years), 147 measurements of IFX-TLs were available (median 4.69 μg/ mL [1.32-9.16]), and 99 AEs (67.3%, 14 severe) were registered. The median IFX-TL of patients with AEs was 5.79 μg/mL (1.36- 10.25), higher than the median IFX-TL of patients without AEs (3.40 μg/mL [1.30-5.92]), but the difference was not significant (P= 0.97). The presence of infections or dermatologic reactions was not correlated with IFX-TLs. There was no difference in the prevalence of the total AEs (66.7% vs. 73.3%, P= 0.77) or in the analysis of AEs by group between patients with IFX-TLs ≥ 15 μg/ mL and patients with IFX-TLs < 15 μg/mL.

CONCLUSIONS

IFX-TLs are not significantly associated with the development of AEs in IBD patients receiving maintenance treatment with IFX.

Strengthened monitoring and optimized management of Crohn's disease patients

In recent years, the treatment goal of Crohn's disease (CD) has shifted from clinical remission to mucosal healing. In this regard, CD management and monitoring are particularly important. Timely adjustment of treatment regimen according to clinical symptoms and inflammatory markers is helpful to monitor patients and achieve better clinical and endoscopic treatment results. However, there is not enough evidence to recommend an optimal treatment regimen that considers only inflammatory markers. Therapeutic drug monitoring (TDM) has been used to improve the treatment of thiopurine and anti-tumor necrosis factor (TNF) drugs. Passive TDM is suitable for all drugs. In order to improve the clinical usefulness, the monitoring of anti-tumor necrosis factor drugs should be transformed from passive to active. The effectiveness of active TDM in optimizing non-anti-TNF biologic agents remains to be described. In addition, inflammatory markers can predict CD recurrence after surgery, and regular colonoscopy at 6-12 mo after surgery is also important. Early postoperative anti-TNF therapy should be considered in high-risk CD patients, but the optimal time for prophylactic administration of anti-TNF therapy is still controversial, and the role of non-anti-TNF biologic agents in prophylactic administration after surgery still needs to be studied. This paper mainly summarizes the monitoring of inflammatory markers, drug monitoring, and postoperative monitoring of patients, so as to optimize the management of CD patients and enable more patients to achieve the treatment goal, and emphasizes the importance of close monitoring of CD patients.

Combination of Biological Agents in Moderate to Severe Pediatric Inflammatory Bowel Disease: A Case Series and Review of the Literature

BACKGROUND

Treatment with biological agents such as anti-tumor necrosis factors (TNFs) has become standard of care in moderate to severe pediatric inflammatory bowel disease (IBD). However, a significant proportion of patients experience loss of response to anti-TNFs, need treatment escalation, or develop side effects. There is no data in the literature regarding combination of biological agents in pediatric IBD.

METHODS

At our hospital, which is a tertiary referral center, we have combined the anti-TNF infliximab with either vedolizumab or ustekinumab in patients with severe pediatric IBD. The indications for dual biological therapy were insufficient efficacy of infliximab or vedolizumab monotherapy, or side effects such as psoriasis due to anti-TNFs.

RESULTS

Eight patients (four boys) aged 14-17.5 years received a combination of infliximab and vedolizumab due to only a partial response to infliximab, four with Crohn's disease (CD) and four with ulcerative colitis (UC). Clinical remission was achieved in four patients (3 UC) and four had a colectomy (3 CD, 1 UC). Five CD patients (3 girls) aged 11-17 years, on maintenance therapy with infliximab, developed psoriasis resistant to topical treatment. A combination of infliximab and ustekinumab resulted in clinical remission of CD without skin symptoms. No serious adverse events occurred in any of the patients on combination therapy. Thirteen publications report on combining biologicals, all in adult IBD.

CONCLUSION

In pediatric IBD, combining biological agents seems to be safe and beneficial in selected patients. The safety should be addressed in long-term follow-up studies.

Pharmacogenetics of trough serum anti-TNF levels in paediatric inflammatory bowel disease

AIMS

Identifying DNA variants associated with trough serum anti-tumour necrosis factor (TNF) levels could predict response to treatment in inflammatory bowel disease (IBD). To date, no specific studies have been performed in children. The aim of this study was to identify genetic variants associated with trough serum anti-TNF levels and whether these variants are differential markers for infliximab and adalimumab.

METHODS

We included 154 children (age < 18 years) from 17 hospitals who had been diagnosed with IBD and actively treated with infliximab or adalimumab. Twenty-one polymorphisms were genotyped using real-time PCR. Trough serum anti-TNF levels were measured using enzyme-linked immunosorbent assay (ELISA). The association between DNA polymorphisms and the therapeutic range or the absolute values of anti-TNF drugs was analysed by Fisher exact test, student's t-test and logistic regression.

RESULTS

The variants rs5030728 (TLR4) and rs11465996 (LY96) were associated with subtherapeutic infliximab levels. rs1816702 (TLR2) was associated with supratherapeutic levels and rs3397 (TNFRSF1B) with subtherapeutic levels of adalimumab (P < .05). In addition, rs1816702 (TLR2) and rs2569190 (CD14) were associated with absolute values of trough serum adalimumab, and rs2569190 (CD14) was associated with absolute values of trough serum adalimumab and infliximab (P < .05).

CONCLUSION

Genotyping of these DNA variants before starting treatment may help to select the best anti-TNF drug in paediatric patients. The SNP rs1816702 is the most promising marker for tailoring the anti-TNF regimen in children with IBD. For the first time, DNA variants are associated with trough serum anti-TNF levels.

Therapeutic drug monitoring in patients on biologics: lessons from gastroenterology

PURPOSE OF REVIEW

To give an overview on the role of therapeutic drug monitoring (TDM) of biologics in patients with inflammatory bowel disease (IBD).

RECENT FINDINGS

Numerous prospective exposure-response relationship studies and post-hoc analyses of randomized controlled trials (RCTs) show a positive correlation between biologic drug concentrations and favorable clinical outcomes in IBD. These studies also demonstrate that higher drug concentrations appear to be needed to achieve more stringent objective therapeutic outcomes. Reactive TDM rationalizes the management of primary nonresponse and secondary loss of response to antitumor necrosis factor (anti-TNF) therapy and is more cost-effective when compared with empiric dose optimization. Furthermore, recent data suggest that proactive TDM, with the goal of targeting a threshold drug concentration, is associated with better therapeutic outcomes when compared with empiric dose escalation and/or reactive TDM of infliximab or adalimumab. Finally, proactive TDM can also efficiently guide infliximab de-escalation or discontinuation in patients with IBD in remission.

SUMMARY

Reactive TDM is currently considered as standard of care, whereas proactive TDM is emerging as a new therapeutic strategy for better optimizing anti-TNF therapy in IBD. However, more data from prospective studies are needed before a wide implementation of TDM-based algorithms in real life clinical practice for newer biologics.

Towards therapeutic drug monitoring of TNF inhibitors for children with juvenile idiopathic arthritis: a scoping review

OBJECTIVES

Before a clinician decides whether treatment with TNF inhibition in children with JIA has failed, one should ensure adequate systemic exposure has been achieved. Therapeutic drug monitoring might allow for improved treatment outcome with lower treatment-associated costs. However, this requires understanding of the pharmacokinetic (PK) characteristics, and the pharmacokinetic/pharmacodynamic (PK/PD) relationship for children with JIA. We performed a scoping review to summarize the available literature and identify areas for future research.

METHODS

A systematic search was conducted of the Medline, EMBASE, Web of Science and Cochrane databases as well as the clinicaltrials.gov registry. In total, 3959 records were screened and 130 publications were selected for full text assessment.

RESULTS

Twenty publications were included and divided into three categories: PK (n = 9), PK/PD (n = 3) and anti-drug antibodies (n = 13). Industry involvement was significant in 14 publications. Although data are limited, systemic exposure to TNF inhibitors is generally lower in younger children but meta-analysis is not possible. The PK/PD relationship has had limited study but there is partial evidence for infliximab. Anti-drug antibodies are common, and are related to impaired clinical outcome with adalimumab and infliximab therapy.

CONCLUSION

The current knowledge about the PK and PK/PD of TNF inhibitors in the treatment of children with JIA is limited, which prevents the introduction of TDM. Re-analysis of available data from previous trials, incorporation of pharmacologic assessments into existing biorepository studies as well as new prospective PK and PK/PD trials are required to obtain this knowledge.

Pharmacokinetics, Pharmacodynamics, and Immunogenicity of Infliximab in Pediatric Inflammatory Bowel Disease: A Systematic Review and Revised Dosing Considerations

OBJECTIVES

Infliximab (IFX), a monoclonal antibody directed against tumor necrosis factor alpha is a potent treatment option for inflammatory bowel disease (IBD). Dosing regimens in children are extrapolated from adult data using a fixed, weight-based dose, which is often not adequate. While clinical trials have focused on safety and efficacy, there is limited data on pharmacokinetic characteristics and immunogenicity of IFX in children. The objective was to provide a systematic overview of current literature on pharmacokinetic and immunogenicity of IFX in children with IBD, to assess the validity of current adult to pediatric dosing extrapolation.

METHODS

A literature search identified publications up to October 2018. Eligibility criteria were study population consisting of children and/or adolescents with IBD, report of IFX trough levels and/or antibodies-to IFX, full text article or abstract, article in English, and original data.

RESULTS

Initial electronic search yielded 2360 potentially relevant articles, with 1831 remaining after removal of duplicates. An additional search yielded another 202 potentially relevant articles. Of the 2033 retrieved articles, 2000 articles were excluded based on title, abstract, or eligibility criteria. Clearance of IFX was increased in young children and children with extensive disease, leading to lower trough levels after extrapolated dosing of 5 mg/kg, antibodies-to IFX emergence, and subsequent reduced efficacy.

CONCLUSIONS

Adult to pediatric weight-based dosing extrapolation is often inadequate. We provide several considerations for optimal dosing of IFX in children and adolescents with IBD.

Effect of a Practice-wide Anti-TNF Proactive Therapeutic Drug Monitoring Program on Outcomes in Pediatric Patients with Inflammatory Bowel Disease

BACKGROUND

Reports on the feasibility and effectiveness of translating proactive, antitumor necrosis factor (TNF) therapeutic drug monitoring (TDM) for inflammatory bowel disease into practice-wide quality improvement (QI) are lacking. We aimed to determine whether a TDM QI program improved outcomes at a large academic pediatric gastroenterology practice.

METHODS

We instituted local anti-TNF TDM practice guidelines to proactively monitor and optimize drug levels (goal >5 μg/mL). We conducted a retrospective single-center cohort analysis of patient outcomes before (pre-TDM) and after (post-TDM) guideline institution and assessed the independent effect by multivariable regression. Primary outcome was sustained clinical remission (SCR22-52), defined as physician global assessment (PGA) of inactive from 22 to 52 weeks and off corticosteroids at 52 weeks.

RESULTS

We identified 108 pre-TDM and 206 post-TDM patients. The SCR22-52 was achieved in 42% of pre-TDM and 59% of post-TDM patients (risk difference, 17.6%; 95% CI, 5.4-29%; P = 0.004). The post-TDM group had an increased adjusted odds of achieving SCR22-52 (odds ratio, 2.03; 95% CI, 1.27-3.26; P = 0.003). The adjusted risk of developing high titer antidrug antibodies (ADAs) was lower in the post-TDM group (hazard ratio, 0.18; 95% CI, 0.09-0.35; P < 0.001). Although the risk of anti-TNF cessation for any reason was not significantly different, there was a lower adjusted risk of cessation related to any detectable ADA in the post-TDM group (hazard ratio, 0.45; 95% CI, 0.26-0.77; P = 0.003).

CONCLUSIONS

A practice-wide proactive anti-TNF TDM QI program improved key clinical outcomes at our institution, including sustained clinical remission, incidence of high titer ADA, and anti-TNF cessation related to ADA.

Post-induction infliximab trough levels and disease activity in the clinical evolution of pediatric ulcerative colitis

BACKGROUND AND AIMS

Recent adult evidence suggests that infliximab (IFX) trough levels (TL) in patients with severe ulcerative colitis (UC) may be decreased. The aims of our study were to compare post-induction IFX TL of children with severe versus moderate UC and to evaluate short- and long-term outcomes.

METHODS

In this single-center retrospective study, children with a diagnosis of UC starting IFX with a Pediatric Ulcerative Colitis Activity Index (PUCAI) ≥35 and with available post-induction TL were recruited. UC characteristics, IFX dosage and interval, primary non-response, IFX failure, and surgery after 24 months were collected. Post induction TL, anti-IFX antibodies, and laboratory evaluations at the time of starting IFX were also acquired.

RESULTS

A total of 90 children were enrolled, of whom 39 (43.3%) were classified as severe UC and 51 (56.6%) as moderate UC. Median post-induction IFX TL were lower in severe UC versus moderate group (5.5 vs 10.3; p = 0.03), despite a more frequently intensified IFX regimen. Children in the higher TL quartiles showed increased rates of clinical, biological, and combined remission (p = 0.04, p < 0.001, and p = 0.01, respectively). In a multivariate analysis, a PUCAI ≥65 and time interval from last IFX infusion were the only predictors associated with IFX TL. At 24 months, children in the higher TL quartiles had a decreased risk of IFX failure (p = 0.002). The severe UC group showed a higher risk of IFX failure at 24 months (16/23 (41%) vs. 11/40 (21.6%); p = 0.05). Kaplan-Meier methods demonstrated a trend toward statistical significance, with a two-year cumulative colectomy rate of 15.38% (95% confidence interval (CI) 8.1-15.6%) in children with severe UC and 3.92% (95% CI 2.9-10.8%) in patients with moderate UC (logrank test p = 0.06).

CONCLUSIONS

Children starting IFX with severe UC showed lower post-induction TL and poor disease outcomes. Achieving adequate TL was associated with better efficacy outcomes.

Trough Levels of Infliximab at Week 6 Are Predictive of Remission at Week 14 in Pediatric Crohn's Disease

OBJECTIVE

Infliximab (IFX) is a frequent therapeutic option for Crohn disease (CD) patients. Early detection of responders to IFX is critical for the management of CD in order to avoid long-term exposure to the drug without benefit. This retrospective study aimed at analysing which early parameters recorded during the induction period are able to predict response to IFX during the maintenance period in pediatric CD.

PATIENTS AND METHODS

Medical records of all CD patients ages from 2 to 18 years who received IFX at a tertiary IBD center were retrospectively analyzed. Children were classified in 3 groups according to their response at week 14 (W14) remission, clinical response or , no response. The factors recorded at W0, W2, and W6, which were associated with remission at W14 were analyzed using a logistic regression.

RESULTS

Among the 111 patients included, 74.8% patients were responders to IFX at W14, including 38.7% in clinical remission and 36% with partial clinical response. Clinical remission at W14 was associated with normal growth (P < 0.01), and normal albuminemia (P = 0.01) at baseline, It was also associated with trough levels to IFX >8.3 μg/ml at week 6 (P < 0.01).

CONCLUSION

Trough levels to IFX >8.3 μg/ml at week 6 are predictive of remission at W14 for luminal disease.

Long-term outcome of immunomodulator use in pediatric patients with inflammatory bowel disease

OBJECTIVES

In the era where new biologicals are entering the market, the place of immunomodulators in the treatment of pediatric inflammatory bowel disease (IBD) needs to be reassessed.

METHODS

All children with Crohn's disease (CD) or ulcerative colitis (UC) followed at our center over the last 10 years were reviewed. Children who received conventional therapy (including 5-aminosalicylates, steroids, thiopurines and methotrexate) since diagnosis were included. Primary outcome was steroid-free clinical remission without need for rescue therapy (biologics or surgery) at 6 and 12 months after diagnosis and at last follow-up. Cox proportional hazard modelling was performed to determine variables at diagnosis associated with outcomes.

RESULTS

In total, 176 IBD patients (121 CD, 55 UC) were identified with a median follow-up of 4.6 [2.0-8.1] years. Remission rates were 79.6% at month 6, but decreased to 60.2% at month 12, and 31.8% at last follow-up. Higher CRP [1.006 (1.001-1.011)], lower albumin [1.050 (1.012-1.086)] and growth impairment [1.214 (1.014-1.373)] in CD patients and higher PUCAI score [1.038 (1.006-1.072)] and low iron [1.023 (1.003-1.043)] in UC patients were associated with treatment failure (all p < 0.05).

CONCLUSION

Only 32% pediatric IBD patients will remain free of biologics or surgery 5-years after diagnosis. Especially children with a high disease burden at diagnosis were more likely to fail conventional therapy.

Infliximab in young paediatric IBD patients: it is all about the dosing

Infliximab (IFX) is administered intravenously using weight-based dosing (5 mg/kg) in inflammatory bowel disease (IBD) patients. Our hypothesis is that especially young children need a more intensive treatment regimen than the current weight-based dose administration. We aimed to assess IFX pharmacokinetics (PK), based on existing therapeutic drug monitoring (TDM) data in IBD patients < 10 years. TDM data were collected retrospectively in 14 centres. Children treated with IFX were included if IFX was started as IBD treatment at age < 10 years (young patients, YP) and PK data were available. Older IBD patients aged 10-18 years were used as controls (older patients, OP). Two hundred and fifteen paediatric inflammatory bowel disease (PIBD) patients were eligible for the study (110 < 10 year; 105 ≥ 10 years). Median age was 8.3 years (IQR 6.9-8.9) in YP compared with 14.3 years (IQR 12.8-15.6) in OP at the start of IFX. At the start of maintenance treatment, 72% of YP had trough levels below therapeutic range (< 5.4 μg/mL). After 1 year of scheduled IFX maintenance treatment, YP required a significantly higher dose per 8 weeks compared with OP (YP; 9.0 mg/kg (IQR 5.0-12.9) vs. OP; 5.5 mg/kg (IQR 5.0-9.3); p < 0.001). The chance to develop antibodies to infliximab was relatively lower in OP than YP (0.329 (95% CI - 1.2 to - 1.01); p < 0.001), while the overall duration of response to IFX was not significantly different (after 2 years 53% (n = 29) in YP vs. 58% (n = 45) in OP; p = 0.56).Conclusion: Intensification of the induction scheme is suggested for PIBD patients aged < 10 years. What is Known? •Infliximab trough levels of paediatric IBD patients are influenced by several factors as dosing scheme, antibodies and inflammatory markers. •In 4.5-30% of the paediatric IBD patients, infliximab treatment was stopped within the first year. What is New? •The majority of young PIBD (< 10 years) have inadequate IFX trough levels at the start of maintenance treatment. •Young PIBD patients (< 10 years) were in need of a more intensive treatment regimen compared with older paediatric patients during 1 year of IFX treatment. •The chance to develop antibodies to infliximab was relatively higher in young PIBD patients (< 10 years).

Therapeutic Drug Monitoring and Outcome of Infliximab Therapy in Pediatric Onset Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) with pediatric onset has become more prevalent during past decades. Thus, the number of patients with moderate to severe disease subtype treated with antagonists to tumor necrosis factor alpha (TNFα) has concurrently risen. Most pediatric patients initially respond to these drugs but will need dose escalation during the first year of therapy. As pediatric data regarding therapeutic drug monitoring during therapy with TNFα-blocker adalimumab are sparse, this review focuses on the literature on therapeutic drug monitoring of infliximab and how it may guide management.

Appropriate Therapeutic Drug Monitoring of Biologic Agents for Patients With Inflammatory Bowel Diseases

BACKGROUND & AIMS

Therapeutic drug monitoring (TDM) is widely available for biologic therapies in patients with inflammatory bowel disease (IBD). We reviewed current data and provided expert opinion regarding the clinical utility of TDM for biologic therapies in IBD.

METHODS

We used a modified Delphi method to establish consensus. A comprehensive literature review was performed regarding the use of TDM of biologic therapy in IBD and presented to international IBD specialists. Subsequently, 28 statements on the application of TDM in clinical practice were rated on a scale of 1 to 10 (1 = strongly disagree and 10 = strongly agree) by each of the panellists. Statements were accepted if 80% or more of the participants agreed with a score ≥7. The remaining statements were discussed and revised based on the available evidence followed by a second round of voting.

RESULTS

The panel agreed on 24 (86%) statements. For anti-tumor necrosis factor (anti-TNF) therapies, proactive TDM was found to be appropriate after induction and at least once during maintenance therapy, but this was not the case for the other biologics. Reactive TDM was appropriate for all agents both for primary non-response and secondary loss of response. The panellists also agreed on several statements regarding TDM and appropriate drug and anti-drug antibody (ADA) concentration thresholds for biologics in specific clinical scenarios.

CONCLUSION

Consensus was achieved towards the utility of TDM of biologics in IBD, particularly anti-TNF therapies. More data are needed especially on non-anti-TNF biologics to further define optimal drug concentration and ADA thresholds as these can vary depending on the therapeutic outcomes assessed.

Refractory Oral Ulcer Responsive to Infliximab: A Case Report

PURPOSE

Some oral ulcers are refractory to treatment. Recently, anti-tumor necrosis factor-alpha (anti-TNF-α) agents have been shown to induce relatively long remissions of refractory oral ulcers.

METHODS

A 69-year man presented with a sore throat caused by a pharyngeal ulcer in the soft palate and subsequently repeatedly developed oropharyngolaryngeal ulcers and an ulcer in the ileocecal region. Intestinal Behçet disease was suspected, but he did not meet the diagnostic criteria for this condition. Seven months after the initial presentation, he developed a lingual ulcer that did not resolve despite treatment with prednisolone. Given the suspicion of intestinal Behçet disease, 300 mg of infliximab was administered intravenously.

RESULTS

After the third dose of infliximab with prednisolone, the ulcer began to improve. He received infliximab every 8 weeks thereafter and developed no new oropharyngolaryngeal ulcers during the 17 months after the first infusion of infliximab.

CONCLUSIONS

When a patient has refractory oral ulcers, attention must be paid to digestive symptoms and whether the patient has a systemic disease such as Behçet disease investigated. Furthermore, administration of infliximab to patients with refractory ulcers can be considered even when they do not fulfill the clinical criteria for a systemic disease.

Therapeutic drug monitoring in inflammatory bowel disease: for every patient and every drug?

PURPOSE OF REVIEW

The current review provides an updated overview on the role of therapeutic drug monitoring (TDM) of biological therapies in inflammatory bowel disease (IBD). We examine the data behind TDM for the antitumor necrosis factor agents, vedolizumab and ustekinumab, in patients with IBD. In addition, we discuss reactive vs. proactive TDM.

RECENT FINDINGS

There is a positive correlation between biologic drug concentrations and favorable therapeutic outcomes in IBD, although the majority of data refer to antitumor necrosis factor therapy. Reactive TDM has rationalized the management of patients with IBD with loss of response to biological therapy. Moreover, reactive TDM of infliximab has been proven to be more cost-effective when compared with empiric dose optimization. Preliminary data suggest that proactive TDM of infliximab and adalimumab applied in patients with clinical response/remission is associated with better therapeutic outcomes compared with standard of care (empiric treatment and/or reactive TDM).

SUMMARY

For all biologics in IBD, there is a positive correlation between drug concentrations and favorable therapeutic outcomes. Reactive TDM is the new standard of care for optimizing biologic therapies in IBD, whereas recent data suggest an important role of proactive TDM for optimizing antitumor necrosis factor therapy in IBD.

Therapeutic drug monitoring to improve outcome of anti-TNF drugs in pediatric inflammatory bowel disease

Introduction: Medical treatment of pediatric inflammatory bowel diseases (IBD) has been greatly changed by the introduction of a number of biologic agents that are able to target various players of the immune response. In particular, monoclonal antibodies against the pro-inflammatory cytokine TNF-alpha (TNF) such as infliximab, adalimumab, and golimumab are now in the clinics both in induction and maintenance therapy, and several efforts are currently ongoing to optimize the use of these drugs in children. Areas covered: This review focuses on therapeutic drug monitoring (TDM) of anti-TNF levels and antidrug antibodies (ADAs), in IBD children. A revision of the analytical assays used for assessing anti-TNF plasma levels is also provided. Expert opinion: Although there is a consensus across studies that higher anti-TNF trough levels are associated with a better clinical outcome, and that early anti-TNF serum measurements could be predictive of long-term response, it is still not clear what the best predictive time of sampling is and what the ideal target drug plasma concentration to achieve. Indeed, there are a number of published studies, particularly in pediatric cohorts, limited by the population size analyzed and more prospective large studies are needed to examine the value of these predictive markers.

Adequate Infliximab Exposure During Induction Predicts Remission in Paediatric Patients With Inflammatory Bowel Disease

OBJECTIVES

Therapeutic drug monitoring has been proposed as a useful tool in the management of infliximab (IFX) treated patients with inflammatory bowel disease. The aim of this retrospective study was to determine whether IFX trough levels after induction therapy are predictive for outcome at week 52.

METHODS

All pediatric patients with inflammatory bowel disease receiving maintenance IFX at our centre, with IFX trough level available at their first maintenance infusion and a follow-up of at least 52 weeks were included. IFX induction regimens could be intensified at the discretion of the treating physician. All children received proactive drug monitoring during maintenance with dose adaptation aiming to target a therapeutic window of 3 to 7 μg/mL.

RESULTS

We included 35 children (23 with Crohn disease and 12 with ulcerative colitis). Median IFX trough levels just before the first maintenance infusion were significantly higher in children achieving clinical (4.6 μg/mL [2.7-11.8] vs 1.5 μg/mL [0.9-3.0]), biological (4.6 μg/mL [2.5-10.3] vs 2.6 μg/mL [0.3-3.2]) and combined clinical/biological remission (6.0 μg/mL [3.2-12.0] vs 2.6 μg/mL [1.1-3.2]) at week 52 compared to children not meeting these criteria (all P ≤ 0.002). Binary logistic regression identified these trough levels as the only predictor for the same outcomes with an odds ratio (95% confidence interval) of 2.083 (1.085-3.998), 2.203 (1.101-4.408), and 2.264 (1.096-4.680), respectively (all P < 0.05).

CONCLUSIONS

Adequate IFX exposure during induction therapy is associated with better clinical and/or biological remission at week 52. Postinduction IFX trough levels were the only predictor for clinical and/or biological remission at week 52.

Infliximab in inflammatory bowel disease

Anti-tumor necrosis factor (TNF) therapy has revolutionized the medical treatment of the inflammatory bowel diseases (IBD), Crohn’s disease (CD), and ulcerative colitis. Twenty years ago, infliximab became the first anti-TNF agent approved for IBD. Data from randomized controlled trials, large observational cohort studies, postmarketing registries, and meta-analyses show that infliximab is a very effective treatment for moderate to severe IBD with a good safety profile. Infliximab has been also used to treat pouchitis following an ileal pouch–anal anastomosis (IPAA) after restorative proctocolectomy and to prevent postoperative recurrence following an ileocolonic resection for CD with good results. Nevertheless, up to 30% of patients show no clinical benefit following induction and up to 50% lose response over time. Both these unwanted outcomes can be largely explained by inadequate drug concentrations and frequently by the development of antibodies to infliximab. Loss of response can be managed efficiently and often prevented by applying therapeutic drug monitoring. Recently, the first biosimilars of infliximab have been approved and are utilized in clinical practice with comparable efficacy and safety with the originator. This review will mainly focus on the efficacy of infliximab in IBD.

Characteristics of biological therapy in pediatric patients with Crohn's disease

INTRODUCTION

At present, there is a significant amount of data related to biologics used in pediatric patients with Crohn's disease. This review characterizes the different biological drugs administered in this population.

AREAS COVERED

Biological therapy of CD, focusing on children, is summarized in this review. After mechanism of action and pharmacokinetics are described, mucosal healing on anti-TNF therapy, aspects of early therapy, long-term outcome and combination therapy are discussed. Moreover, loss of response and treatment optimization, as well as drug withdrawal are summarized. Subsequently, perianal disease and surgical aspects are discussed followed by safety issues. In addition, new drugs (vedolizumab, ustekinumab), cost-effectiveness and administration of biosimilars were also included.

EXPERT COMMENTARY

There are significant data to characterize biological drugs administered in pediatric patients with Crohn's disease. However, head-to-head comparative studies using different biologics are missing.

Therapeutics for Inflammatory Bowel Diseases in Children and Adolescents: A Focus on Biologics and an Individualized Treatment Paradigm

Pharmacologic treatment of children and adolescents with inflammatory bowel diseases (IBD) [Crohn's disease and ulcerative colitis] requires consideration of disease and medication effects on growth and nutrition, the importance of durability of biologics, and concerns for long-term sequelae of disease and therapies. Achieving early remission in children with Crohn's disease correlates with improved outcomes and therefore allows a window of opportunity for maximizing growth. Thus, there is a great need to treat children and adolescents with the right drug at the right time while achieving adequate exposure. Improved understanding of disease phenotypes, disease natural history, and risk stratification will play a critical role in treatment selection for children, particularly as more therapeutic options become available. Here we summarize data supporting newer concepts of treating the individual child with IBD through targeted early biologic treatment, including utilization of therapeutic drug monitoring to optimize treatment effects and the use of early antitumor necrosis factor (TNF)-α therapies to mitigate long-term sequelae of the disease. Recent inception cohort studies provide important data regarding the risk stratification of children and adolescents with IBD, which support a move toward a personalized therapeutic approach to IBD in children and adolescents.