Anti-infliximab antibodies in inflammatory bowel disease: prevalence, infusion reactions, immunosuppression and response, a meta-analysis

Prevalence and clinical implications of anti-drug antibody formation and serum drug levels among patients with IBD receiving anti-TNF therapy: A cross-sectional study

BACKGROUND

The emergence of tumor necrosis factor inhibitors (anti-TNF) has considerably changed the management of inflammatory bowel disease (IBD) in patients who do not respond to traditional therapies. This study assesses the prevalence of anti-TNF drug levels (DLs) and antibodies (ATAbs) in patients with IBD in Saudi Arabia and explores their associations with IBD type and prior anti-TNF failure.

METHODS

This cross-sectional study included patients aged 14-75 years diagnosed with Crohn's disease (CD) or ulcerative colitis (UC), treated with anti-TNF medications at King Fahad Medical City over January 2016 to December 2022. Data were analyzed using descriptive statistics, Mann-Whitney U test, Kruskal-Wallis test, Pearson's Chi-squared test, and multinomial logistic regression.

RESULTS

Among 392 patients with IBD (median age, 31 years), 75.8% were diagnosed with CD and 24.2% with UC. Anti-TNF levels were subtherapeutic in 27.0% patients, therapeutic in 21.5%, and supratherapeutic in 51.5%. ATAbs were negative in 73.1% patients, weakly positive in 9.8%, and positive in 17.1%. Subtherapeutic anti-TNF levels were significantly associated with positive ATAbs ( P < 0.001). Prior anti-TNF therapy failure was observed in 37.2% cases, with 15.3% showing immunogenicity. No significant demographic differences were noted across ATAbs groups.

CONCLUSION

We highlight the prevalence of subtherapeutic and supratherapeutic anti-TNF levels among patients with IBD in Saudi Arabia and their association with ATAbs. The findings underscore the importance of monitoring anti-TNF DLs and ATAbs to optimize treatment outcomes in IBD management. Future research should focus on the longitudinal impact of these factors and explore genetic predictors of treatment response.

Age as a Predictor of Serum Tumor Necrosis Factor Antagonist Drug and Antidrug Antibody Concentrations in Inflammatory Bowel Disease-A Nationwide Cohort Study

Background/Objectives: Tumor necrosis factor antagonists (anti-TNFs) have been shown to be an effective treatment for inflammatory bowel disease (IBD). Several factors are associated with anti-TNF treatment failure. This study aims to explore the impact of age on serum concentrations of anti-TNF drugs and antidrug antibodies (ADAbs). Methods: We retrospectively reviewed patients' charts from July 2018 until September 2024 across seven medical centers. Patients with an established diagnosis of IBD receiving infliximab or adalimumab were included. The primary outcome of this study was the effect of age on the anti-TNFs serum drug concentration and ADAb levels. Linear regression was performed to explore the relationship between age and serum anti-TNF drug and ADAb levels. Results: 1093 patients were included in our cohort. In patients receiving infliximab, there was a significant association between older age and increasing ADAbs levels (p = 0.036), whereas in patients treated with adalimumab, there was no significant relationship between older age and ADAb levels (p = 0.771). There was no significant relationship between age and adalimumab serum concentration (p = 0.54). When stratified by age, patients taking infliximab who were >30 years of age developed more ADAbs compared to those aged ≤30 (p = 0.003). Conclusions: Patients older than 30 years of age receiving infliximab monotherapy have higher ADAbs and lower serum drug concentrations than younger patients. There was no statistically significant difference in ADAbs and serum drug concentrations among patients receiving infliximab combination therapy or adalimumab monotherapy.

Adding Chinese herbal medicine bath therapy to conventional therapies for psoriasis vulgaris: A systematic review with meta-analysis of randomised controlled trials

BACKGROUND

Chinese herbal medicine (CHM) bath is commonly used in China as an adjuvant therapy for managing psoriasis vulgaris. Previous systematic reviews showed that CHM bath therapy was effective and safe for psoriasis vulgaris, however, without exploration of the specifics of CHM bath therapy such as the optimal temperature, duration of each session, and the total treatment duration.

PURPOSE

To evaluate the add-on effects of CHM bath therapy to conventional therapies for adult psoriasis vulgaris.

METHODS

We conducted a comprehensive search in nine medical databases from inception to September 2022 to identify relevant randomised controlled trials (RCTs) published in Chinese or English. The included studies compared the combination of CHM bath therapy and conventional therapies to conventional therapies alone for adult psoriasis vulgaris. Methodological quality assessment of the included RCTs was performed using the Cochrane risk-of-bias tool 2 (RoB 2). Statistical analysis was carried out using RevMan 5.4, R 4.2.3 and Stata 12.0 software. The certainty of evidence of outcome measures was evaluated using the Grading of Recommendations Assessment, Development, and Evaluation Working Group (GRADE) system.

RESULTS

A total of 23 RCTs involving 2,183 participants were included in this systematic review. Findings suggested that the combination of CHM bath therapy and conventional therapies was more effective in reducing Psoriasis Area and Severity Index (PASI), Dermatology Life Quality Index (DLQI) and itch visual analogue scale, compared to using conventional therapies alone. These enhanced effects were notably observed when the CHM bath was set above 38 °C and had a duration of 20 and 30 min, as assessed by DLQI. Moreover, an eight-week treatment duration resulted in better effects for PASI compared to shorter durations. Additionally, the top ten frequently used herbs in the included studies were identified. Despite the findings, the certainty of evidence was rated as 'low' or 'moderate' based on the GRADE assessment, and significant heterogeneity was detected in subgroup and sensitivity analyses.

CONCLUSION

The CHM bath therapy combined with conventional therapies is more effective and safer than conventional therapies alone for adult psoriasis vulgaris. The results suggest a potential correlation between treatment effects and factors such as extended treatment duration, increased bath temperature, and longer bath sessions. However, the certainty of evidence was downgraded due to methodological limitations of the included studies. To confirm the findings of this systematic review, a double-blinded, placebo-controlled RCT is needed in the future.

Systematic Review and Meta-analysis: The Association Between Serum Ustekinumab Trough Concentrations and Treatment Response in Inflammatory Bowel Disease

BACKGROUND

Optimizing therapy and monitoring response are integral aspects of inflammatory bowel disease treatment. We conducted a systematic review and meta-analysis to determine whether serum ustekinumab trough concentrations during maintenance therapy were associated with ustekinumab treatment response in patients with inflammatory bowel disease.

METHODS

A systematic review was performed to March 21, 2022, to identify studies using MEDLINE, EMBASE, and the Cochrane library. We included studies that reported the association between serum ustekinumab trough concentrations with clinical or endoscopic remission. Outcome measures were combined across studies using the random-effects model with an odds ratio (OR) for binary outcomes of endoscopic and clinical remission.

RESULTS

We identified 14 observational studies that were included in the analysis for clinical remission (919 patients, 63% with Crohn's disease) or endoscopic remission (290 patients, all with Crohn's disease). Median ustekinumab trough concentrations were higher amongst individuals achieving clinical remission compared with those not achieving remission (mean difference, 1.6 ug/mL; 95% confidence interval [CI], 0.21-3.01 ug/mL). Furthermore, individuals with median serum trough concentration in the fourth quartile were significantly more likely to achieve clinical (OR, 3.61; 95% CI, 2.11-6.20) but not endoscopic remission (OR, 4.67; 95% CI, 0.86-25.19) compared with those with first quartile median trough concentrations.

CONCLUSION

Based on the results of this meta-analysis primarily relating to patients with Crohn's disease on maintenance ustekinumab treatment, it appears that there is an association between higher ustekinumab trough concentration and clinical outcomes. Prospective studies are required to determine whether proactive dose adjustments of ustekinumab therapy provides additional clinical benefit.

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.

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.

Certolizumab Trough Levels and Antibodies in Crohn Disease: A Single-Center Experience

Background

Certolizumab pegol (CZP) has been successfully used for the treatment of Crohn disease (CD); however, real-world data regarding the utility of CZP trough levels (CTLs) are lacking. We aimed to correlate CTL with CD outcomes and to determine frequency of CZP antibodies.

Methods

Retrospective evaluation of all CD patients on maintenance CZP with CTL obtained between 2016 and 2019. Outcomes included: median CTL, presence of anti-CZP antibodies, biochemical response (BR), clinical response (CR), radiologic response (RR), radiologic healing (RH), and mucosal healing (MH).

Results

Seventy-seven CD patients were included. Median CTL was 18.9 µg/mL (interquartile range, 7.6-35.4). Twenty-three patients (27.3%) had positive antibody levels, with lower median CTL compared to patients with no antibodies (0.0 vs 29.8; P < 0.0001). Median CTL levels were higher in patients with vs without CR (30.4 vs 10.3 µg/mL; P = 0.0015) and RR (29.6 vs 5.8 µg/mL; P = 0.006). CZP dosing at least every 2 weeks was associated with higher odds of achieving MH (odds ratio, 3.2; 95% confidence interval, 1.03-9.97). CTL resulted in change in clinical management in 62.7% of cases and presence of CMZ antibodies was associated with an odds ratio of 5.83 (95% confidence interval, 1.57-21.73) of change in management. Receiver operating characteristic curve and quartile analysis suggested that CTL >19 µg/mL is associated with increased rates of CR and RR.

Conclusions

Higher CTL was significantly associated with CR and RR. The rate of CZP antibodies was 27.3%. Our data suggest maintenance CTL of ≥19 µg/mL should be achieved in order to optimize outcomes in clinical practice.

Predictors of Infliximab Trough Concentrations in Inflammatory Bowel Disease Patients Using a Repeated-Measures Design

BACKGROUND AND AIMS

Treating patients based on a treat-to-trough approach has been shown to be a cost-effective strategy for inflammatory bowel disease (IBD) patients who have become unresponsive to infliximab (IFX). However, the documented evidence for this is limited, and some controversy remains regarding the use of routine proactive therapeutic drug monitoring (TDM). To support routine TDM of IFX and regimen optimization in IBD patients, more in-depth knowledge of the covariates that affect the pharmacokinetic (PK) variability of IFX is needed. The aim of this study was to identify the characteristics of the patient, disease, and treatments that influence IFX PK and exposure in our cohort of IBD patients using a repeated-measures design.

METHODS

We performed a prospective observational study of adult IBD patients who received IFX between July 2013 and March 2017. We obtained repeated IFX trough concentration (Cmin) measurements and implemented a previously described population pharmacokinetic model to estimate individual clearance (CL). From the individual primary parameters, the area under the curve (AUC), half-life (t1/2), and central elimination rate constant (K10) were estimated. We performed a repeated-measures analysis to evaluate whether patient characteristics, disease status, concomitant immunosuppressive therapy, and immunogenicity are associated with IFX Cmin and PK parameters.

RESULTS

We collected 429 Cmin measurements from 112 patients. The median of the Cmin values was 3.62 mg/L (1.47-6.02). Antibodies to IFX (ATI) were detected in 14 patients. The predicted median AUC was 28,421 mg/h/L (22,336-36,903). The median individual predicted CL, K10, and t1/2 values were 4.77 mL/kg/day (3.88-5.90), 0.09 days (0.08-0.12), and 12.22 days (9.49-14.87), respectively. IFX Cmin, AUC, CL, and K10 were significantly influenced by ATI and serum albumin concentrations. Moreover, body weight was significantly associated with AUC, CL, and K10. Patients receiving concurrent immunosuppressive therapy had higher Cmin and AUC values and lower CL and K10 values than those treated with IFX monotherapy. We also observed high intrapatient variability in Cmin values during the study period.

CONCLUSIONS

In this repeated-measures study in a population of IBD patients, we observed significant associations between ATI, serum albumin concentration, concomitant immunosuppressive therapy, body weight and gender, and IFX Cmin, and CL. The high PK variability observed in this study supports the need for proactive TDM to optimize the use of IFX as early as possible in IBD patients.

Biological therapy in pediatric age

Biological therapies, especially blocking tumor necrosis factor-α (TNFα) agents have radically changed the therapeutic approach and disease course of pediatric inflammatory bowel disease (IBD). In particular, drugs such as infliximab (IFX) and adalimumab (ADA) have been demonstrated to be effective in inducing and maintaining corticosteroid-free remission in both adult and pediatric patients with Crohns Disease (CD) and Ulcerative colitis (UC). Biosimilar biological (BioS) therapy is increasingly being used in pediatric age even though most knowledge on the safety and efficacy of these agents is based on IFX in adult IBD data. Studies show high rates of clinical response and remission in both IFX naïve patients and in patients switched from originator to BioS with similar risks of adverse events (AEs) as those reported with IFX originator. In the present review indications, efficacy and AEs of biological therapy in pediatric IBD will be discussed, as well as the role of other biological agents such as Golimumab, Vedolizumab and Ustekinumab, the role of BioS biological therapy and utility of therapeutic drug monitoring in clinical practice.

Inflammatory Bowel Disease - Non-biological treatment

Nowadays, non-biological treatments remain valuable approaches among the therapeutic armamentarium of inflammatory bowel disease (IBD). Mesalamine is the core treatment of mild‑to‑moderate ulcerative colitis (UC) and corticosteroids are crucial for the induction of remission of moderate‑to‑severe flares in both UC and Crohn's disease (CD). Even approaches as cyclosporine, tacrolimus, azathioprine, methotrexate, and surgery still have a nuclear position as strategies to induce and/or maintain remission in IBD. Due to their particularities and to the accumulated evidence, each of these strategies conquered peculiar roles in the overall IBD strategy, all of them contributing to better outcomes. This review emphasizes the particular roles that non-biological treatments gained over time: recent mesalamine formulations to increase adhesion rates, higher doses of 5-ASA for high-risk patients, MMX technology to improve drug release and attain higher bowel concentrations, cyclosporine as a bridge to vedolizumab, tacrolimus as a potential alternative to thiopurines or infliximab, azathioprine in combination therapy with infliximab and dubious in monotherapy, and surgery as a mean to a "better end".

A 3-year prospective study of a multidisciplinary early proactive therapeutic drug monitoring programme of infliximab treatments in inflammatory bowel disease

AIMS

Therapeutic drug monitoring (TDM) of trough serum infliximab concentrations has been mainly used in case of loss of response in patients with inflammatory bowel disease (IBD). The aim of this study was to evaluate the effectiveness and safety of a multidisciplinary early proactive TDM (mep-TDM) programme for dose adjustment.

METHODS

A 3-year prospective study was conducted based on a sample of 81 patients who started treatment and were subsequently subjected to mep-TDM with the first control at week 14. Data of a historical control group of 72 patients treated with infliximab and managed with empirical dosing were included. Effectiveness variables were treatment failure, IBD-related surgery and IBD-related hospitalization. Safety variables were serious infusion reactions (SIRs) and adverse reactions. Cox regression was used for survival analysis.

RESULTS

In the mep-TDM study group, compared to the control group, there was a significant reduction in the risk of treatment failure (hazard ratio [HR]: 0.51; 95% confidence interval [CI]: 0.27-0.92; P = .037), IBD-related surgery (HR: 0.14; 95% CI: 0.03-0.65; P = .012) and hospitalization (HR: 0.38; 95% CI: 0.17-0.87; P = .022). SIRs were lower in the mep-TDM group (2.5% vs 10.4%; P < .050); the incidence of adverse reactions was similar (3.7% vs 3.9%; p > .999).

CONCLUSION

This study found that compared to empirical dosing, mep-TDM is associated with improved efficacy and safety of infliximab therapy, reduced IBD-related hospitalization and surgery and incidence of SIRs, and increasing long-term durability of treatment effects.

Value Assessment and Quantitative Benefit-Risk Modelling of Biosimilar Infliximab for Crohn's Disease

BACKGROUND AND OBJECTIVE

Regulatory approval of biosimilars often depends on extrapolating evidence from one clinical indication to all of those of the originator biologic. We aimed to develop a quantitative benefit-risk analysis to assess whether the resulting increase in the uncertainty in the clinical performance of biosimilars (i.e. risk) may be countered by their lower pricing (benefit).

METHODS

A 1-year decision-analytic model was developed for the biosimilar infliximab (Inflectra^®) for Crohn's disease. The perspective was that of the National Health Service in the UK and costs were valued to 2015/16. A hypothetical cohort of biologic-naïve patients with moderate-to-severe Crohn's disease was simulated through the model. Immunogenicity to infliximab was a key modifier, influencing rates of non-response and infusion reactions. Net health benefit was estimated based on quality-adjusted life-years. A range of sensitivity analyses tested the robustness of the results and explored how the biosimilar price must respond to varying immunogenicity to remain the preferred option.

RESULTS

The base-case analysis predicted a positive incremental net health benefit of 0.04 (95% central range 0.00-0.09) favouring the biosimilar, based on 0.803 quality-adjusted life-years, and costs of £18,087 and £19,176 for the biosimilar and originator, respectively. Two-way sensitivity analyses suggested that if 50% of patients developed antibodies, the value-based price of £410 per vial must be lower than that of the originator (£420), but remain higher than the actual market price (£378).

CONCLUSIONS

The model supports the use of Inflecta^® for Crohn's disease in the UK, and provides a framework for the quantitative evaluation of biosimilars in the context of a health technology assessment. Value-based pricing using this methodology could protect health systems from the potential risks of biosimilars where they are untested in the approved populations.

Is It Possible to Discontinue Tumor Necrosis Factor Antagonists after Psoriasis Remission?

Tumor necrosis factor (TNF) antagonists are highly effective treatments for psoriasis. These agents provide the opportunity to improve disease activity and achieve clinical remission. Despite its efficacy, long-term use of biologics is associated with high financial costs and possibly life-threatening adverse events. Recently, there has been an increasing interest in discontinuing TNF antagonists in patients with psoriasis who have achieved a positive clinical response. However, there is a paucity of data and clinical guidelines concerning the cessation TNF antagonists in psoriasis treatment. Several factors, including cost, subsequent treatment efficacy, relative risks, and tolerability, should be considered before the decision is made to discontinue TNF antagonists. Well-designed clinical trials are necessary to identify factors that may trigger disease exacerbation after medication discontinuation in order to recognize the potential disadvantages of discontinuing treatment in patients who are previously successfully managed on TNF antagonists.

Implications of Monoclonal Antibody Therapeutics Use for Clinical Laboratory Testing

BACKGROUND

Monoclonal antibody therapeutics (MATs) represent a rapidly expanding class of biological drugs used to treat a variety of diseases. The widespread use of MATs increasingly affects clinical laboratory medicine.

CONTENT

This review provides an overview of MATs currently approved for clinical use in the US, starting from basic biology of antibodies to the engineering, pharmacokinetic and pharmacodynamic properties, nomenclature, and production of MATs. Immunogenicity and the production of antidrug antibodies (ADAs) play a major role in loss of therapeutic response and the development of treatment failure to certain MATs. Laboratory-based monitoring for MATs and detection of ADAs represent emerging needs for optimizing the use of MATs to achieve the best outcomes at affordable cost. In addition, the increased use of MATs affects clinical laboratory testing by interference of MATs with clinical laboratory tests across different areas of laboratory medicine, including histocompatibility, blood bank, and monoclonal protein testing.

SUMMARY

The number of MATs is rapidly growing each year to address previously unmet clinical needs. Laboratory monitoring of MATs and detecting ADAs represent expanding areas of laboratory testing. Test-based strategies allow for treatment optimization at the level of the individual patient, thus providing a personalized medicine approach. In addition, clinical laboratories must be aware that the increasing use of MATs affects laboratory testing and be ready to implement methods to eliminate or mitigate interference with clinical tests.

Joint AAD-NPF guidelines of care for the management and treatment of psoriasis with biologics

Psoriasis is a chronic, inflammatory multisystem disease that affects up to 3.2% of the US population. This guideline addresses important clinical questions that arise in psoriasis management and care, providing recommendations based on the available evidence. The treatment of psoriasis with biologic agents will be reviewed, emphasizing treatment recommendations and the role of the dermatologist in monitoring and educating patients regarding benefits as well as associated risks.

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.

Proactively Optimized Infliximab Monotherapy Is as Effective as Combination Therapy in IBD

BACKGROUND

Infliximab (IFX) discontinuation is not uncommon during the first year of treatment due to inadequate drug concentrations and anti-IFX antibodies (ATI). Both combination therapy and proactive therapeutic drug monitoring (pTDM) are used to decrease ATI and increase IFX durability. We proposed that monotherapy (Mono) is as effective as combination therapy (Combo) if the first maintenance infusion is dosed based on week 10 pTDM.

METHODS

In a retrospective cohort of 83 patients with inflammatory bowel disease (IBD), we examined the frequency of IFX discontinuation, ATI, infusion reactions, and IFX concentrations during the first year of treatment in patients receiving week 10 pTDM-guided IFX monotherapy (Mono pTDM; n = 16) compared with patients on mono (n = 32) or combination therapy (n = 35) in whom TDM was introduced at or after week 14, per standard of care (SOC).

RESULTS

The frequency of IFX discontinuation was lower with Mono pTDM compared with Mono SOC (P = 0.04) but did not differ with Combo SOC (P = 1). At first TDM, no patient in the pTDM strategy had ATI, vs 41% in Mono SOC (P = 0.002) and 6% in Combo SOC (P = 1). Of the 13 subjects with ATI in Mono SOC, 7 (47%) had ATI already at week 14. IFX trough concentrations with Mono pTDM were higher during maintenance compared with Mono SOC (9.5 vs 6.4 µg/mL, P = 0.04) but not Combo SOC.

CONCLUSIONS

Infliximab durability did not differ between patients on IFX monotherapy dosed based on p-TDM and patients receiving combination therapy. In the absence of concomitant immunosuppression, proactive TDM may improve IFX durability by maintaining higher IFX concentrations entering into maintenance. Further studies are needed to confirm our findings.

Outcomes of Perianal Fistulising Crohn's Disease Following Anti-TNFα Treatment Discontinuation

BACKGROUND

Discontinuation of antitumour necrosis factor (TNF)α therapy with perianal fistulising Crohn's disease remains controversial due to the risk of severe relapse without any clear evidence.

AIM

The aim of this study was to assess the rate and type of perianal and luminal relapses following anti-TNFα discontinuation.

METHODS

All patients treated with anti-TNFα for perianal fistulising Crohn's disease with subsequent discontinuation of therapy were retrospectively reviewed from a prospective database (1998-2016). Cumulative probabilities of relapse-free survival were estimated by actuarial analysis.

RESULTS

After a median follow-up of 62 months, 24 of the 45 patients experienced perianal relapse. A new surgical drainage was needed in 19 (79%) patients. The cumulative probabilities of perianal relapse at 1 and 5 years were 24% and 55%, respectively. Ileal localization (L1) at diagnosis, persistence of an external fistula opening, second line anti-TNFα use, or prior dose optimization was associated with perianal relapse, whereas continuation of immunosuppressive agents decreased this risk (HR = 0.3). Luminal relapse occurred in 42% of patients at 5 years. The cumulative probability of global relapse at 5 years was 67%. Retreatment with anti-TNFα allowed further remission in 23 of 24 (96%) patients.

CONCLUSION

Half of patients with perianal fistulising Crohn's disease relapse within 5 years after anti-TNFα discontinuation. Immunosuppressant continuation may decrease this risk. The high risk of relapse (perianal and luminal) may suggest a benefit in pursuing biologics over a longer period in patients with perianal fistulas.

Clinical effectiveness and cost-effectiveness of use of therapeutic monitoring of tumour necrosis factor alpha (TNF-α) inhibitors [LISA-TRACKER® enzyme-linked immunosorbent assay (ELISA) kits, TNF-α-Blocker ELISA kits and Promonitor® ELISA kits] versus standard care in patients with Crohn's disease: systematic reviews and economic modelling

BACKGROUND AND OBJECTIVES

Systematic reviews and economic modelling of clinical effectiveness and cost-effectiveness of therapeutic monitoring of tumour necrosis factor alpha (TNF-α) inhibitors [using LISA-TRACKER^® enzyme-linked immunosorbent assay (ELISA) kits (Theradiag, Marne La Vallee, France, or Alpha Laboratories, Heriot, UK), TNF-α-Blocker ELISA kits (Immundiagnostik AG, Bensheim, Germany) and Promonitor^® ELISA kits (Proteomika, Progenika Biopharma, Bizkaia, Spain)] versus standard care for Crohn's disease (CD).

METHODS

Multiple electronic databases were searched from inception to December 2014 in order to identify primary studies and meta-analyses.

POPULATION

Patients with moderate to severe active CD treated with infliximab (IFX) (Remicade^®, Merck Sharp & Dohme Ltd, Kenilworth, NJ, USA) or adalimumab (ADA) (Humira^®, AbbVie Inc., North Chicago, IL, USA).

INTERVENTION

Monitoring of serum anti-TNF-α (IFX or ADA) and/or of anti-drug antibody levels using test assays with a test-treatment algorithm.

COMPARATOR

Standard care.

OUTCOMES

Any patient-related outcome, test agreement and cost-effectiveness estimates. The quality assessments used recognised checklists (Quality Assessment of Diagnostic Accuracy Studies-2, Cochrane, Philips and Consolidated Health Economic Evaluation Reporting Standards). Evidence was synthesised using narrative review and meta-analysis. A Markov model was built in TreeAge Pro 2013 (TreeAge Software, Inc., Williamstown, MA, USA). The model had a 4-week cycle and a 10-year time horizon, adopted a NHS and Personal Social Services perspective and used a linked evidence approach. Costs were adjusted to 2013/14 prices and discounted at 3.5%.

RESULTS

We included 68 out of 2434 and 4 out of 2466 studies for the clinical effectiveness and cost-effectiveness reviews, respectively. Twenty-three studies comparing test methods were identified. Evidence on test concordance was sparse and contradictory, offering scant data for a linked evidence approach. Three studies [two randomised controlled trials (RCTs) and one retrospective observational study] investigated outcomes following implementation of a test algorithm. None used the specified commercial ELISA immunoassay test kits. Neither of the two RCTs demonstrated clinical benefit of a test-treatment regimen. A meta-analysis of 31 studies to estimate test accuracy for predicting clinical status indicated that 20-30% of test results are likely to be inaccurate. The four cost-effectiveness studies suggested that testing results in small cost reductions. In the economic analysis the base-case analysis showed that standard practice (no testing/therapeutic monitoring with the intervention tests) was more costly and more effective than testing for IFX. Sensitivity and scenario analyses gave similar results. The probabilistic sensitivity analysis indicated a 92% likelihood that the 'no-testing' strategy was cost-effective at a willingness to pay of £20,000 per quality-adjusted life-year.

STRENGTHS AND LIMITATIONS

Rigorous systematic reviews were undertaken; however, the underlying evidence base was poor or lacking. There was uncertainty about a linked evidence approach and a lack of gold standard for assay comparison. The only comparative evidence available for economic evaluation was for assays other than the intervention assays.

CONCLUSIONS

Our finding that testing is not cost-effective for IFX should be viewed cautiously in view of the limited evidence. Clinicians should be mindful of variation in performance of different assays and of the absence of standardised approaches to patient assessment and treatment algorithms.

FUTURE WORK RECOMMENDATIONS

There is substantial variation in the underlying treatment pathways and uncertainty in the relative effectiveness of assay- and test-based treatment algorithms, which requires further investigation. There is very little research evidence on ADA or on drug monitoring in children with CD, and conclusions on cost-effectiveness could not be reached for these.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42014015278.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Concomitant Therapy with Immunomodulator Enhances Infliximab Durability in Pediatric Inflammatory Bowel Disease

BACKGROUND

Data on long-term durability of infliximab (IFX) and outcomes of concomitant therapy with immunomodulator in pediatric inflammatory bowel disease are limited.

METHODS

Children with inflammatory bowel disease who received IFX ± immunomodulator were retrospectively reviewed. Predictors of induction response were assessed using a binary logistic regression model and long-term outcomes evaluated by Cox proportional hazards model. Propensity score matching examined long-term efficacy of concomitant therapy in patients with Crohn's disease (CD).

RESULTS

Among 148 patients (113 CD, 35 ulcerative colitis; median age at IFX initiation 14.09 years [interquartile range 12.16-15.65]), 91% experienced response to induction therapy; patients with CD were more likely to respond (95% versus 77%, odds ratio = 2.63, 95% confidence interval, 1.01-6.85, P = 0.048). Despite dose optimization, secondary loss of response occurred at a rate of 9.01% and 8.33% per year for patients with CD and ulcerative colitis, respectively. A Cox proportional hazards model showed that concomitant therapy >6 months significantly lowered the risk of secondary loss of response in CD (hazard ratio = 0.39, 95% confidence interval, 0.17-0.88, P = 0.025). The same trend was observed in ulcerative colitis but did not reach significance. A higher proportion of patients on IFX monotherapy stopped IFX because of loss of response or infusion reactions (55% versus 21%, P < 0.001). Propensity score analysis of patients with CD showed significantly higher steroid-free remission rates for concomitant versus monotherapy at 1 year (78% versus 54%, P = 0.020) and 2 years (68% versus 46%, P = 0.044), and durability of response (P = 0.022).

CONCLUSIONS

These data demonstrate sustained efficacy of IFX in a cohort of pediatric patients with inflammatory bowel disease with durability of response enhanced by concomitant therapy.

Less Anti-infliximab Antibody Formation in Paediatric Crohn Patients on Concomitant Immunomodulators

OBJECTIVES

To evaluate the effect of immunomodulators on formation of antibodies to infliximab (ATI) in paediatric patients with Crohn disease (CD) and the association of ATI and loss of response.

METHODS

Retrospective multicentre observational study (January 2009-December 2014) among Dutch children with CD treated with infliximab (IFX). ATI formation was analysed with Chi-square test and time-to-ATI formation with Kaplan-Meier and log-rank test.

RESULTS

A total of 229 children were identified. ATIs were measured in 162 patients (70.7%) and 25 (15%) developed ATIs: 6 of 62 (10%) on continuous combined immunosuppression (CCI), 11 of 81 (14%) on early combined immunosuppression (ECI), and 8 of 19 (42%) on IFX monotherapy. ATI formation was higher in patients on IFX monotherapy compared to CCI (P = 0.003) and ECI (P = 0.008), whereas no significant difference was found between CCI and ECI. Sixteen out of 25 patients (64%) with ATIs had loss of response, compared with 32 of 137 patients (19%) without ATIs (P < 0.00002, log rank 0.02). Among patients treated with ECI, 10 of 55 (18%) developed ATIs within the first 12 months, compared to 1 of 26 (4%) after more than 12 months.

CONCLUSIONS

In children with CD combination therapy is associated with significant reduction of antibody formation and prolonged effectivity compared to IFX monotherapy. ECI for at least 12 months, followed by IFX monotherapy, may be an equally effective alternative to CCI.

Thiopurines Dosed to a Therapeutic 6-Thioguanine Level in Combination with Adalimumab Are More Effective Than Subtherapeutic Thiopurine-based Combination Therapy or Adalimumab Monotherapy During Induction and Maintenance in Patients with Long-standing Crohn's Disease

BACKGROUND

The benefit of concomitant immunomodulation with adalimumab (ADA) in Crohn's disease is poorly understood. We aimed to compare ADA monotherapy with combination therapy with thiopurines, stratified by thioguanine nucleotides (TGNs).

METHODS

Retrospective observational study of ADA induction and maintenance. Thiopurines were classified according to TGNs (>235 pmol/8 × 10 red blood cell therapeutic).

RESULTS

At induction, response was more frequent in combination than ADA monotherapy (83% versus 61%, P = 0.02) and with therapeutic compared with subtherapeutic TGNs (87% versus 70% P = 0.011). Among 280 maintenance semesters in 91 patients, remission was higher with combination than monotherapy (81% versus 60%, P < 0.0001) and therapeutic versus subtherapeutic TGNs (85% versus 58%, P = 0.004). Therapeutic TGN (odds ratio [OR] 4.32, 95% CI, 1.41-13.29, P = 0.01) and albumin (OR 1.09, 95% CI, 1.01-1.18, P = 0.03) were predictors of response to induction. Therapeutic TGN (OR 3.71, 95% CI, 1.87-7.34, P < 0.0001) and ileal disease (OR 0.21, 95% CI, 0.08-0.57, P = 0.002) were predictors of remission semesters. Concomitant immunomodulation at induction was associated with longer time to failure (69 versus 36 months, P = 0.009). Therapeutic TGN at induction (P = 0.03) and male sex (P = 0.026) were associated with time to failure.

CONCLUSIONS

Combination therapy was superior to ADA monotherapy for induction and during maintenance. This benefit was increased further when thiopurines resulted in therapeutic TGNs. Early use of adequately dosed thiopurines (≥3 months before starting ADA) was associated with improved clinical outcomes.

Test accuracy of drug and antibody assays for predicting response to antitumour necrosis factor treatment in Crohn's disease: a systematic review and meta-analysis

OBJECTIVE

To present meta-analytic test accuracy estimates of levels of antitumour necrosis factor (anti-TNF) and antibodies to anti-TNF to predict loss of response or lack of regaining response in patients with anti-TNF managed Crohn's disease.

METHODS

MEDLINE, Embase, the Cochrane Library and Science Citation Index were searched from inception to October/November 2014 to identify studies which reported 2×2 table data of the association between levels of anti-TNF or its antibodies and clinical status. Hierarchical/bivariate meta-analysis was undertaken with the user-written 'metandi' package of Harbord and Whiting using Stata V.11 software, for infliximab, adalimumab,anti-infliximab and anti-adalimumab levels as predictors of loss of response. Prevalence of Crohn's disease in included studies was meta-analysed using a random effects model in MetaAnalyst software to calculate positive and negative predictive values. The search was updated in January 2017.

RESULTS

31 studies were included in the review. Studies were heterogeneous with respect to the type of test used, criteria for establishing response and loss of response, population examined and results. Meta-analytic summary point estimates for sensitivity and specificity were 65.7% and 80.6% for infliximab trough levels and 56% and 79% for antibodies to infliximab, respectively. Pooled results for adalimumab trough levels and antibodies to adalimumab were similar. Pooled positive and negative predictive values ranged between 70% and 80% implying that between 20% and 30% of both positive and negative test results may be incorrect in predicting loss of response.

CONCLUSION

The available evidence suggests that these tests have modest predictive accuracy for clinical status; direct test accuracy comparisons in the same population are needed. More clinical trial evidence from test-treat studies is required before the clinical utility of the tests can be reliably evaluated.

Utilisation of anti-TNF levels in a UK tertiary IBD centre

OBJECTIVE

To ascertain how anti-tumour necrosis factor (TNF) drug and anti-drug antibody levels testing is used in a 'real-world' setting to optimise inflammatory bowel disease (IBD) treatment.

DESIGN

Retrospective cohort study of prospectively collected patient data.

SETTING

Tertiary IBD centre in London, UK.

PATIENTS

All patients at Guy's and St Thomas' Hospitals on anti-TNF who had levels measured between the start of testing in 2012 and October 2014.

INTERVENTIONS

Anti-TNF drug and anti-drug antibody levels as part of routine monitoring.

MAIN OUTCOME MEASURES

Indication for measuring levels and changes in management made as a result of the levels.

RESULTS

330 infliximab levels were carried out in 199 patients and 143 adalimumab levels were carried out in 103 patients. Levels were primarily done in those with evidence of loss of response; 37% of infliximab levels and 52% of adalimumab levels. Levels resulted in a change in management in 26% of patients in infliximab group and 25% of patients in adalimumab group; however, this was greater in those with loss of response, 62% and 61% respectively. Anti-drug antibodies were detected in 7% of patients.

CONCLUSIONS

Our early experience has demonstrated that measuring anti-TNF drug and anti-drug antibody levels can be useful in the optimisation of IBD management. In an increasing number of patients, particularly those with evidence of loss of response, it allows early decisions to be made regarding changing therapy. It also offers the potential for significant cost-saving by preventing pointless dose escalation in the context of therapeutic levels or when high-level anti-drug antibodies are present.

Clinical role, optimal timing and frequency of serum infliximab and anti-infliximab antibody level measurements in patients with inflammatory bowel disease

BACKGROUND

Serum infliximab (IFX) and antibody-to-infliximab (ATI) levels are objective parameters, that may have a great role in the therapeutic decisions during maintenance biological therapy.

RESEARCH DESIGN AND METHODS

48 inflammatory bowel disease patients receiving maintenance IFX therapy were prospectively enrolled and divided into adequate (complete remission N = 20) and inadequate responder (partial response, loss of response, dose escalation; N = 28) groups. Blood samples were collected just before (trough level, TL) and two (W2aTL) and six weeks (W6aTL) after the administration of IFX.

RESULTS

Single measurement of ATI titer was insufficient for predicting therapeutic response due to transient expression of ATI, however, using the three points' measurements, significant difference has been detected between the adequate and inadequate responder group (5.0% vs 35.7%; p = 0.016). The mean value of TL was significantly higher in the adequate responder group (3.11±1.64 vs.1.19±1.11; p<0.001) without further difference on the second and sixth week. Sensitivity and specificity for predicting the therapeutic response were 85.0% and 71.4% based on the cut-off value of TL 2.0 μg/ml.

CONCLUSION

Simultaneous measurement of serum IFX level prior to administration of regular IFX infusion and ATI titers significantly increase the diagnostic accuracy for the therapeutic decision in patients uncertainly responding to the therapy. The measurement of W2aTL and W6aTL levels did not result in further improvement in the prediction of therapeutic response.

Long-Term Outcomes and Predictors of Sustained Response in Patients with Intestinal Behcet's Disease Treated with Infliximab

BACKGROUND

Intestinal Behcet's disease (BD) is a specific subtype of BD. Effective drug therapy for intestinal BD remains elusive.

AIMS

To investigate long-term outcomes and identify predictors of sustained response in intestinal BD patients receiving infliximab (IFX) treatment.

METHODS

The medical records were reviewed of patients received IFX from September 2012 to March 2016. The cumulative probabilities of sustained response were calculated using the Kaplan-Meier. Predictor factors for sustained response were accessed by receiver operating characteristic curve.

RESULTS

Totally, 27 active intestinal BD patients were enrolled. Sustained responses were observed in 17 patients, after a median follow-up duration 24 months (interquartile range 9-37). The proportion of clinical remission at week 14, 30, and 52 had occurred in 84.6, 70, and 70%, respectively, with the proportion of clinical remission of 69.2, 40, and 55%. The mucosal healing (MH) rate at week 14 was 72%. Kaplan-Meier estimated patients with achievement of clinical and biological responses at week 14 or MH was likely to remain sustained clinical response. ROC curve analysis revealed CRP level (of 6.85 mg/L) at week 14 is a potential predictor for discriminating patients with sustained response from relapse, with an area under the curve values of 0.837.

CONCLUSIONS

IFX is effective and safe for induction and maintenance therapy in Chinese patients with moderate-to-severe active intestinal BD. Early achievement of clinical response and mucosal healing might associate long-term response. A lower CRP level seems to be associated with a more benign clinical course.

Clinical impact of immunomonitoring in the treatment of inflammatory bowel disease

Despite improvement in outcomes, loss of response (LOR) to tumor necrosis factor-alpha (TNFα) therapies is a big concern in the management of inflammatory bowel disease. LOR is associated with flares of disease, increased hospitalisation rates, need for surgical interventions, and decline in quality of life. LOR may be multifactorial, but immunogenicity makes a significant contribution. Traditionally doses of anti-TNFα have been adjusted based on clinical response, using a standard approach. Immunomonitoring involves the measurement of anti-TNFα trough and antibody levels. It takes into account the underlying pharmacokinetics of anti-TNFα therapies. Expanding on this a treat to target approach may be used, where doses are intensified, or tailored to the individual based on the measurement of anti-TNFα trough and antibody levels. This review looks at the history, evolution, and clinical impact that immunomonitoring is having in the treatment of inflammatory bowel disease. It will focus on the role of immunomonitoring in helping to achieve long lasting deep remission and mucosal healing. It will explore the different options in terms of best measuring trough and antibody levels, explore possible advantages of immunomonitoring, and discuss its role in best optimising response, at induction, during the maintenance phase of treatment, as well as a role in withdrawing or switching therapy.

Standardization of the homogeneous mobility shift assay protocol for evaluation of anti-infliximab antibodies. Application of the method to Crohn's disease patients treated with infliximab

BACKGROUND

The availability of a quantitative method to measure anti-infliximab (IFX) antibodies (ATI) would facilitate the implementation of therapeutic drug monitoring in clinical decision-making. Our aim was to standardize the homogeneous mobility shift assay (HMSA) used in the measure of ATI levels.

METHODS

In this prospective longitudinal multicenter study, 50 IFX-treated Crohn's disease (CD) patients were followed up for 54weeks. During this period 360 human serum samples were analysed. Monomeric ATI levels were measured by a quantitative HMSA-method using an anti-IFX calibrator. IFX trough levels measured by ELISA were correlated with ATI levels.

RESULTS

Using HMSA and a pure anti-idiotypic monoclonal antibody specific for IFX (anti-IFX calibrator), we measured the levels of monomeric ATI generated in Crohn's disease patients treated with IFX. Anti-IFX calibrator allowed to quantify monomeric antibodies against IFX with a low limit of quantification (3nM). The threshold level of ATI in order to classify the immunogenicity of the patients was 10nM. We observed that 24% (12/50) of IFX-treated patients developed ATI (>10nM) during the observation period (54weeks). Serum concentration of ATI higher than 10nM dramatically increased the probability (OR=51.1; 95% CI: 20.4-128.0; p<0.0001) of presenting low levels of IFX (⩽1.5nM) in serum, as observed in some CD patients treated with standard doses of the drug.

CONCLUSIONS

The HMSA-method described here allows an accurate quantification of ATI concentration in international units (IU) and therefore it could be useful in the study of the relationship between ATI concentration, infliximab level and the clinical response to the drug.

Optimizing Treatment with TNF Inhibitors in Inflammatory Bowel Disease by Monitoring Drug Levels and Antidrug Antibodies

BACKGROUND

Biological tumor necrosis factor (TNF) inhibitors have revolutionized the treatment of inflammatory bowel disease and redefined treatment goals to include mucosal healing. Clinicians are faced with challenges such as inadequate responses, treatment failures, side effects, and high drug costs. The objective is to review optimization of anti-TNF therapy by use of personalized treatment strategies based on circulating drug levels and antidrug antibodies (Abs), i.e. therapeutic drug monitoring (TDM). Furthermore, to outline TDM-related pitfalls and their prevention.

METHODS

Literature review.

RESULTS

Circulating anti-TNF drug trough level is a marker for the pharmacokinetics (PK) of TNF inhibitors. Because of a number of factors, including antidrug antibodies, PK varies between and within patients across time leading to variable clinical outcomes. Differences in intestinal inflammatory phenotype influencing the pharmacodynamic (PD) responses to TNF inhibitors also affect treatment outcomes. As an alternative to handling anti-TNF-treated patients by empiric strategies, TDM identifies underlying PK and PD-related reasons for treatment failure and aids decision making to secure optimal clinical and economic outcomes. Although promising, evidence does not the support use of TDM to counteract treatment failure in quiescent disease. Use of TDM is challenged by methodological biases, difficulties related to differentiation between PK and PD problems, and temporal biases due to lack of chronology between changes in PK versus symptomatic and objective disease activity manifestations. Biases can be accommodated by knowledgeable interpretation of results obtained by validated assays with clinically established thresholds, and by repeated assessments over time using complimentary techniques.

CONCLUSIONS

TDM-guided anti-TNF therapy at treatment failure has been brought from bench to bedside.

Anti-TNF drug and antidrug antibody level monitoring in IBD: a practical guide

The antitumour necrosis factor (TNF) medications, adalimumab and infliximab, play an important role in the management of both Crohn's disease and ulcerative colitis. For those in whom anti-TNF is effective, the therapy is associated with fewer symptoms, improved quality of life and disease and surgery-free survival. Unfortunately, up to 30% of patients will fail to respond to anti-TNF drugs while up to 50% of those who do see an initial response will lose response at some point. The introduction of drug monitoring for anti-TNFs, including drug level and antidrug antibody level testing allows a more personalised management of patients and improves patient outcomes. This article reviews the data for the use of anti-TNF monitoring and presents a 'how to' guide for clinicians.

First trough level of infliximab at week 2 predicts future outcomes of induction therapy in ulcerative colitis-results from a multicenter prospective randomized controlled trial and its post hoc analysis

BACKGROUND

Infliximab (IFX) is one of the treatments of choice for corticosteroid-refractory and corticosteroid-dependent ulcerative colitis (UC). A high serum trough level of IFX (TL) is reported to be associated with sustained efficacy during maintenance treatment. As part of a phase 3 randomized controlled trial of IFX in UC, we assessed the predictive value of the first TL at week 2 for short- and long-term response.

METHODS

Patients received intravenous IFX 5 mg/kg or placebo at weeks 0, 2, and 6. Patients with evidence of a response by week 8 continued treatment at weeks 14 and 22. TL was measured by enzyme-linked immunosorbent assay. Post hoc analysis was then performed for TL and clinical outcomes.

RESULTS

Clinical response rate at week 8, the primary end point, was significantly higher in the IFX group than placebo (p = 0.005). The incidence of adverse events between groups was similar. Week 2 TL was significantly associated with a 14-week clinical activity index (CAI) remission. In multiple logistic regression analysis, the week 2 TL-to-CAI ratio (TL/CAI, odds ratio 8.07; 95% confidence interval 2.84-27.07, p < 0.001) was an independent factor correlating with 14-week CAI remission. The week 2 TL and TL/CAI were also significantly associated with 30-week mucosal healing.

CONCLUSIONS

IFX was confirmed to be effective and safe in this population. Our results suggest that the first TL at week 2, in combination with clinical evaluation, is useful for predicting both short- and long-term outcomes, allowing an earlier decision between continuing IFX or switching to other options.

Use of Placebo in Pediatric Inflammatory Bowel Diseases: A Position Paper From ESPGHAN, ECCO, PIBDnet, and the Canadian Children IBD Network

Performing well-designed and ethical trials in pediatric inflammatory bowel diseases (IBD) is a priority to support optimal therapy and reduce the unacceptable long lag between adult and pediatric drug approval. Recently, clinical trials in children have been incorporating placebo arms into their protocols under conditions that created controversy. Therefore, 4 organizations (the European Society for Pediatric Gastroenterology, Hepatology, and Nutrition; European Crohn's and Colitis Organization; the Canadian Children IBD Network; and the Global Pediatric IBD Network) jointly provide a statement on the role of placebo in pediatric IBD trials. Consensus was achieved by 94 of 100 (94%) voting committees' members that placebo should only be used if there is genuine equipoise between the active treatment and placebo; for example, this may be considered in trials of drugs with new mechanisms of action without existing adult data, especially when proven effective alternatives do not exist outside the trial. Placebo may also be used in situations where it is an "add-on" to an effective therapy or to evaluate exit-strategies of maintenance therapy after long-term deep remission. It has been, however, agreed that no child enrolled in a trial should receive a known inferior treatment both within and outside the trial. This also includes withholding therapy in children who show clinical response after a short induction therapy. Given the similarity between pediatric and adult IBD regarding pathophysiology and response to treatments, drugs generally cannot be considered being in genuine equipoise with placebo if it has proven efficacy in adults. Continued collaboration of all stakeholders is needed to facilitate drug development and evaluation in pediatric IBD.

Infliximab-Related Infusion Reactions: Systematic Review

OBJECTIVE

Administration of infliximab is associated with a well-recognised risk of infusion reactions. Lack of a mechanism-based rationale for their prevention, and absence of adequate and well-controlled studies, has led to the use of diverse empirical administration protocols. The aim of this study is to perform a systematic review of the evidence behind the strategies for preventing infusion reactions to infliximab, and for controlling the reactions once they occur.

METHODS

We conducted extensive search of electronic databases of MEDLINE [PubMed] for reports that communicate various aspects of infusion reactions to infliximab in IBD patients.

RESULTS

We examined full texts of 105 potentially eligible articles. No randomised controlled trials that pre-defined infusion reaction as a primary outcome were found. Three RCTs evaluated infusion reactions as a secondary outcome; another four RCTs included infusion reactions in the safety evaluation analysis; and 62 additional studies focused on various aspects of mechanism/s, risk, primary and secondary preventive measures, and management algorithms. Seven studies were added by a manual search of reference lists of the relevant articles. A total of 76 original studies were included in quantitative analysis of the existing strategies.

CONCLUSIONS

There is still paucity of systematic and controlled data on the risk, prevention, and management of infusion reactions to infliximab. We present working algorithms based on systematic and extensive review of the available data. More randomised controlled trials are needed in order to investigate the efficacy of the proposed preventive and management algorithms.

Serum trough infliximab and anti-infliximab antibodies in a cohort of gastroenterology and rheumatology patients' infliximab therapeutic drug monitoring

BACKGROUND

Infliximab, a monoclonal antibody directed against tumour necrosis factor, is widely used in the treatment of chronic inflammatory conditions including Crohn's disease and rheumatoid arthritis. Its use is limited by development of anti-infliximab antibodies, which can lead to loss of therapeutic efficacy. Serum infliximab and anti-infliximab antibody measurements have recently become routinely available in the UK. The study aimed to assess the clinical utility of antibodies as an adjunct to trough infliximab.

METHODS

Serum trough infliximab was measured in 201 samples from 108 gastroenterology and rheumatology patients on maintenance infliximab therapy. Results were correlated with C-reactive protein concentrations. Total anti-infliximab antibodies were measured in 164 samples.

RESULTS

The median (25th-75th percentile) trough infliximab was 3.7 µg/mL (1.2-5.2 µg/mL) and 23% of samples had a concentration ≤1 µg/mL. A notable proportion had positive anti-infliximab antibodies: 84/164 (51%), which subdivided to 85% and 28% with infliximab ≤1 and >1 µg/mL, respectively.Serum C-reactive protein was found to be significantly higher where infliximab was ≤1 compared to >1 µg/mL (10 mg/L [<5-24 mg/L] vs. <5 mg/L [<5-8 mg/L], P < 0.01), although a strict correlation was not observed. The relationship between trough infliximab and C-reactive protein differed depending on antibody status and there was no association between C-reactive protein and the presence or absence of antibodies.

CONCLUSION

Our findings support measurement of anti-infliximab antibodies only in the context of low infliximab concentrations <1 µg/mL. A higher therapeutic cut-off may be relevant in patients with negative antibodies. Further work is indicated to investigate the clinical significance of positive antibodies with therapeutic infliximab concentrations.

A Saudi Gastroenterology association position statement on the use of tumor necrosis factor-alfa antagonists for the treatment of inflammatory bowel disease

The objective of this position statement from the Saudi Gastroenterology Association is to guide gastroenterologists on the use of tumor necrosis factor-alfa (TNF-α) antagonists for the treatment of the idiopathic inflammatory bowel diseases, Crohn's disease, and ulcerative colitis. In this article, we summarize the relevant literature regarding the safety and efficacy of TNF-α antagonists, highlight relevant safety concerns specific to the environment in Saudi Arabia, and provide specific recommendations for the use of these agents.

Benefit of infliximab reintroduction after successive failure of infliximab and adalimumab in Crohn's disease

BACKGROUND

Infliximab [IFX] and adalimumab [ADA] are effective in Crohn's disease [CD] for induction and maintenance therapy. However, high annual rate of discontinuation for loss of response or intolerance may lead to a switch to another anti-tumor necrosis factor agent. Patients with successive failure to IFX and ADA are becoming more frequent. The aim of this study was to assess the efficacy and the tolerance of re-treatment with IFX in CD patients who successively failed IFX and ADA.

METHODS

A total of 61 patients with CD who received and discontinued successively IFX and ADA, and who were re-exposed to IFX, were identified in four French tertiary centers and retrospectively analyzed. Clinical data, follow-up and outcome were abstracted from medical records.

RESULTS

Median treatment duration after reintroduction was 16 months, and probability of remaining under IFX was 60% and 51%, respectively, at 12 and 24 months. In all 29 patients discontinued the second IFX treatment due to intolerance [13], primary non-response [8], loss of response [7] or patient's wish [1]. Remission was achieved in 42% at week 6-8 after IFX re-induction, and was predictive of better long-term response [p = 0.006]. In multivariate analysis, receiving co-immunosuppression in both first and second IFX treatments [p = 0.04] and shorter interval between first and second IFX treatments [p = 0.017] were independently associated with longer duration of second IFX treatment.

CONCLUSION

For CD patients who successively failed IFX and ADA, reintroducing IFX is feasible and often clinically efficient, particularly in patients who received co-immunosuppression during both first and second IFX treatments.

Changes in serum trough levels of infliximab during treatment intensification but not in anti-infliximab antibody detection are associated with clinical outcomes after therapeutic failure in Crohn's disease

BACKGROUND AND AIMS

Intensification of the infliximab (IFX) regimen is recommended if the treatment effect is inadequate. However, the rationale for this is not well defined as the underlying mechanisms vary. The aim of this study was to explore the association between changes in serum IFX and anti-IFX antibodies (Abs) after IFX intensification and clinical outcomes.

METHODS

We performed a post hoc analysis of a randomized clinical trial including 42 Crohn's disease patients with IFX treatment failure, all treated with an intensified IFX regimen (5mg/kg every 4 week) for 12 weeks. Trough serum IFX and anti-IFX Ab concentrations were measured by a homogeneous mobility shift binding assay (HMSA) and a functional cell-based reporter gene assay (RGA) at treatment failure and the end of the trial.

RESULTS

Twenty-one patients (50%) regained clinical response on the intensified IFX regimen. The increase in serum trough levels of IFX during treatment intensification was higher among responders than non-responders (RGA, 8.8 versus 3.0 μg/mL, p = 0.035; HMSA, 9.9 versus 4.7 μg/mL, p = 0.040), and differentiated patients by clinical outcome (RGA, area under receiver operating characteristic curve [AUC] 0.75 [0.53-0.97], p = 0.035; HMSA, AUC 0.74 [0.53-0.95], p = 0.042). All responders exhibited an IFX increase ≥2.6 μg/mL (sensitivity 100%, specificity 50%). Anti-IFX Abs detected by HMSA in 13 patients (32%) were often non-functional and became undetectable during IFX intensification. However, even functional anti-IFX Abs detected by RGA in six patients (15%) became undetectable.

CONCLUSION

Increase in IFX levels following treatment intensification was associated with improved clinical outcomes, indicating insufficient drug levels in a subgroup of patients. Anti-IFX Abs may become undetectable during treatment intensification, suggesting lowered production or the formation of immune complexes.

Therapeutic drug monitoring of infliximab in inflammatory bowel disease patients in a teaching hospital setting: results of a prospective cohort study

OBJECTIVE

Therapeutic drug monitoring (TDM) of infliximab (IFX) is not routinely implemented in our clinical practice. We therefore carried out a prospective cohort study measuring IFX trough levels in our total inflammatory bowel disease (IBD) population in relation to remission.

METHODS

Patient demographics, and medication and clinical history were collected from the electronic hospital information system. Blood was drawn at one time point for the determination of IFX trough levels and antibodies to IFX (ATI). Disease activity indices [Crohn's disease activity index (CDAI) and the Truelove-Witts disease activity index (TWDAI) for Crohn's disease and ulcerative colitis, respectively] and quality-of-life scores (Visual Analog Scale) were obtained.

RESULTS

We included 107 patients. IFX levels varied from less than 0.02 to 21.9 μg/ml. The median IFX level was 2.8 μg/ml [interquartile range (IQR) 1.37-5.13]. The IFX level was associated significantly with remission (P=0.007). The median IFX level was 3.9 μg/ml (IQR 1.9-6.53) in patients in remission and 2.1 μg/ml in patients with active disease (IQR 0.77-4.38) (P=0.074). Receiver operating charecteristic curve analysis indicated a cutoff value of 2.18 μg/ml for CD and 6.26 μg/ml for UC. Eleven patients (10.3%) had developed ATI. The appearance of ATI was associated with the disappearance of IFX [relative risk: 2.2 (95% confidence interval: 1.368-3.610) P<0.0001], but not with relapse. The presence of ATI induced more infusion reactions [relative risk: 11.7 (95% confidence interval: 2.74-49.60) P<0.001].

CONCLUSION

TDM of IFX in IBD outpatients in a teaching hospital setting showed large interindividual differences in IFX trough levels. Despite this, we still found a significant association between remission and IFX trough levels. We determined cutoff values for both IBD modalities. IFX trough levels were not detectable in a significant proportion of IBD patients; TDM is indicated to identify this group of patients.

Classical and recent advances in the treatment of inflammatory bowel diseases

Crohn's disease (CD) and ulcerative colitis (UC) are intestinal disorders that comprise the inflammatory bowel diseases (IBD). These disorders have a significant effect on the quality of life of affected patients and the increasing number of IBD cases worldwide is a growing concern. Because of the overall burden of IBD and its multifactorial etiology, efforts have been made to improve the medical management of these inflammatory conditions. The classical therapeutic strategies aim to control the exacerbated host immune response with aminosalicylates, antibiotics, corticosteroids, thiopurines, methotrexate and anti-tumor necrosis factor (TNF) biological agents. Although successful in the treatment of several CD or UC conditions, these drugs have limited effectiveness, and variable responses may culminate in unpredictable outcomes. The ideal therapy should reduce inflammation without inducing immunosuppression, and remains a challenge to health care personnel. Recently, a number of additional approaches to IBD therapy, such as new target molecules for biological agents and cellular therapy, have shown promising results. A deeper understanding of IBD pathogenesis and the availability of novel therapies are needed to improve therapeutic success. This review describes the overall key features of therapies currently employed in clinical practice as well as novel and future alternative IBD treatment methods.

Crohn's disease outpatients treated with adalimumab have an earlier secondary loss of response and requirement for dose escalation compared to infliximab: a real life cohort study

BACKGROUND

The efficacy of anti-tumor necrosis factor alpha agents in maintaining remission in Crohn's disease may wane over time, leading to secondary loss of response that can often be overcome with dose escalation. Comparison of secondary loss of response of adalimumab and infliximab during long-term treatment of CD in a real-life IBD clinic has not been previously evaluated.

METHODS

A retrospective cohort study was conducted evaluating outpatients with CD on a maintenance regimen with adalimumab or infliximab from 200 to 2013 and who experienced a secondary loss of response. All infliximab-treated patients were anti-TNF naïve. Adalimumab-treated patients were stratified by prior anti-TNF exposure. Kaplan-Meier analysis was conducted to compare time to loss of response.

RESULTS

218 CD patients met inclusion criteria (117 infliximab, 101 adalimumab). Median follow-up duration was 170.0weeks for infliximab and 122.0weeks for adalimumab (p=0.61). The proportion of patients with secondary loss of response was similar for infliximab-treated - 51.3% (60/117) compared to adalimumab patients naïve to anti-TNF therapy - 60.5% (23/38) (p=0.32), and adalimumab patients with prior anti-TNF exposure - 65.1% (41/63) (p=0.08). Median time to secondary loss of response was longer for infliximab patients (99.3wk, IQR 55.7-168.5) compared to both adalimumab patients naïve to anti-TNF therapy (58.9wk, IQR 29.0-85.7) (p=0.03), and adalimumab patients with prior anti-TNF exposure (52.7wk, IQR 20.1-85.0) (p<0.001).

CONCLUSIONS

Over 50% of CD patients treated with infliximab and adalimumab develop secondary loss of response. Time to loss of response was shorter in patients treated with adalimumab compared to those treated with infliximab. Prior anti-TNF exposure further accelerated time to loss of response.

Consensus guidelines of ECCO/ESPGHAN on the medical management of pediatric Crohn's disease

Children and adolescents with Crohn's disease (CD) present often with a more complicated disease course compared to adult patients. In addition, the potential impact of CD on growth, pubertal and emotional development of patients underlines the need for a specific management strategy of pediatric-onset CD. To develop the first evidenced based and consensus driven guidelines for pediatric-onset CD an expert panel of 33 IBD specialists was formed after an open call within the European Crohn's and Colitis Organisation and the European Society of Pediatric Gastroenterolog, Hepatology and Nutrition. The aim was to base on a thorough review of existing evidence a state of the art guidance on the medical treatment and long term management of children and adolescents with CD, with individualized treatment algorithms based on a benefit-risk analysis according to different clinical scenarios. In children and adolescents who did not have finished their growth, exclusive enteral nutrition (EEN) is the induction therapy of first choice due to its excellent safety profile, preferable over corticosteroids, which are equipotential to induce remission. The majority of patients with pediatric-onset CD require immunomodulator based maintenance therapy. The experts discuss several factors potentially predictive for poor disease outcome (such as severe perianal fistulizing disease, severe stricturing/penetrating disease, severe growth retardation, panenteric disease, persistent severe disease despite adequate induction therapy), which may incite to an anti-TNF-based top down approach. These guidelines are intended to give practical (whenever possible evidence-based) answers to (pediatric) gastroenterologists who take care of children and adolescents with CD; they are not meant to be a rule or legal standard, since many different clinical scenario exist requiring treatment strategies not covered by or different from these guidelines.

Clinical implications of measuring drug and anti-drug antibodies by different assays when optimizing infliximab treatment failure in Crohn's disease: post hoc analysis of a randomized controlled trial

OBJECTIVES

Cost-effective guidance of therapeutic strategy in Crohn's disease patients with secondary infliximab (IFX) treatment failure may be achieved by serum IFX and anti-IFX antibody (Ab) measurements by radioimmunoassay (RIA). This study investigated implications of using other techniques for this purpose.

METHODS

This is a post hoc analysis of randomized clinical trial including 66 Crohn's disease patients with IFX failure in whom IFX and anti-IFX Ab measurements by RIA had been used for therapeutic guidance. Samples were additionally assessed by enzyme-linked immunosorbent assay (ELISA), homogeneous mobility shift assay (HMSA), and functional cell-based reporter gene assay (RGA).

RESULTS

IFX detection was comparable between assays (82% RIA, 76% ELISA, 88% HMSA, and 74% RGA), and it correlated significantly (Pearson's r=0.91-0.97, P<0.0001). However, IFX concentrations varied systematically between all pair of assays except RIA-RGA. Anti-IFX Ab detection was variable (27% RIA, 9% ELISA, 33% HMSA, and 11% RGA), but correlated significantly (Pearson's r=0.77-0.96; P<0.0001). Anti-IFX Abs detected by RIA and HMSA were often from sera without drug-neutralizing activity (RGA). Assays agreed on classification of underlying mechanism for treatment failure in most cases (79-94%). The majority (74-88%) failed IFX owing to pharmacodynamic problems, or had noninflammatory pathophysiology for symptoms resembling relapse. Applied threshold for therapeutic vs. subtherapeutic IFX level influenced classifications. The four different assays did not differ in terms of the ability to predict response to interventions defined by the algorithm.

CONCLUSIONS

Despite variable analytical properties, common assays result in similar classifications and interventions in patients with IFX treatment failure, and with comparable clinical outcomes. Implications are, however, profound for the minority classified differently.

Are we using and monitoring thiopurines and biologics optimally?

The use of biologics and thiopurines in patients with inflammatory bowel disease has increased rapidly over the last 2 decades with both classes of drugs being used more frequently and earlier in the disease course. This vogue has come about through a realisation that for some patients Crohn's disease and ulcerative colitis are progressive diseases and that use of these therapies can sometimes prevent that progression. However, knowledge about the optimal way in which to use these drugs continues to evolve. In this paper, the evidence regarding optimal timing and dosing of thiopurines and biologics will be reviewed as will the role of thiopurine methyltransferase testing along with therapeutic drug monitoring of both thiopurines and biologics. In addition, possible future applications of biologic drug level and anti-drug antibody testing will be considered.

Individualised therapy is more cost-effective than dose intensification in patients with Crohn's disease who lose response to anti-TNF treatment: a randomised, controlled trial

OBJECTIVE

Although the reasons for secondary loss of response to infliximab (IFX) maintenance therapy in Crohn's disease vary, dose intensification is usually recommended. This study investigated the cost-effectiveness of interventions defined by an algorithm designed to identify specific reasons for therapeutic failure.

DESIGN

Randomised, controlled, single-blind, multicentre study. 69 patients with secondary IFX failure were randomised to IFX dose intensification (5 mg/kg every 4 weeks) (n=36) or interventions based on serum IFX and IFX antibody levels using the proposed algorithm (n=33). Predefined co-primary end points at week 12 were proportion of patients responding (Crohn's Disease Activity Index (CDAI) decrease ≥ 70, or ≥ 50% reduction in active fistulas) and accumulated costs related to treatment of Crohn's disease, expressed as mean cost per patient, based on the Danish National Patient Registry for all hospitalisation and outpatient costs in the Danish healthcare sector.

RESULTS

Costs for intention-to-treat patients were substantially lower (34%) for those treated in accordance with the algorithm than by IFX dose intensification: € 6038 vs € 9178, p<0.001. However, disease control, as judged by response rates, was similar: 58% and 53%, respectively, p=0.81; difference 5% (-19% to 28%). For per-protocol patients, treatment costs were even lower (56%) in the algorithm-treated group (€ 4062 vs € 9178, p<0.001) and with similar response rates (47% vs 53%, p=0.78; difference -5% (-33% to 22%)).

CONCLUSIONS

Treatment of secondary IFX failure using an algorithm based on combined IFX and IFX antibody measurements significantly reduces average treatment costs per patient compared with routine IFX dose escalation and without any apparent negative effect on clinical efficacy.

TRIAL REGISTRATION NO

NCT00851565.

Can we get more from our current treatments?

Crohn's disease is a chronic incurable condition that normally requires lifelong treatment. Whilst the anti-TNF agents have revolutionised the management of Crohn's disease over the last fifteen years, they are not a panacea. In particular, in part due to their immunogenic nature, loss of response limits their long term effectiveness in many patients. The only other long term disease-modifying options are the immunomodulators, methotrexate, azathioprine and mercaptopurine. Therefore, given the limited number of drugs available to treat Crohn's disease, it is important that efforts are made to ensure that drugs are used in the best way possible as once a drug is deemed ineffective, it is rarely used again. For the growing number of patients who have active disease despite having been exposed to all standard therapies, failure to optimise drug therapy may lead to missed opportunities in the management of their disease. In this review, optimisation of drugs commonly used in the management of Crohn's disease will be discussed.