Individualized Therapy Is a Long-Term Cost-Effective Method Compared to Dose Intensification in Crohn's Disease Patients Failing Infliximab

The cost of inflammatory bowel disease in high-income settings: a Lancet Gastroenterology & Hepatology Commission

The cost of caring for patients with inflammatory bowel disease (IBD) continues to increase worldwide. The cause is not only a steady increase in the prevalence of Crohn's disease and ulcerative colitis in both developed and newly industrialised countries, but also the chronic nature of the diseases, the need for long-term, often expensive treatments, the use of more intensive disease monitoring strategies, and the effect of the diseases on economic productivity. This Commission draws together a wide range of expertise to discuss the current costs of IBD care, the drivers of increasing costs, and how to deliver affordable care for IBD in the future. The key conclusions are that (1) increases in health-care costs must be evaluated against improved disease management and reductions in indirect costs, and (2) that overarching systems for data interoperability, registries, and big data approaches must be established for continuous assessment of effectiveness, costs, and the cost-effectiveness of care. International collaborations should be sought out to evaluate novel models of care (eg, value-based health care, including integrated health care, and participatory health-care models), as well as to improve the education and training of clinicians, patients, and policy makers.

Proactive monitoring of anti-TNF agents improves follow-up of paediatric patients with Crohn disease

INTRODUCTION AND AIMS

The incidence of paediatric inflammatory bowel disease has increased in recent decades. The aim of the present study was to evaluate the role of proactive and serial monitoring of tumour necrosis factor (TNF) inhibitor levels to maintain clinical remission and mucosal healing in the follow-up of paediatric patients with Crohn disease (CD).

METHODS

Prospective study that included all patients diagnosed with CD and treated with adalimumab or infliximab between May 2015 and November 2020 who underwent serial and proactive monitoring of TNF inhibitor levels.

RESULTS

The study included 30 patients, 21 male (70%). The mean age at diagnosis was 11.3 years (SD, 2.0), the mean age at initiation of TNF inhibitors was 12.6 years (SD, 1.9) with a mean duration of follow-up of 27.1 ± 9.1 months. Clinical remission was defined as a weighted Pediatric Crohn's Disease Activity Index (wPCDAI) of less than 12.5 and mucosal healing as a Mucosal Inflammation Non-invasive Index (MINI) of less than 8. During the follow-up, patients were in clinical remission in 87.1% of the visits, presented with mild disease in 11.4% and with moderate disease in 1.5%, and mucosal healing was assumed in 83% of the visits. The rates of clinical remission and mucosal healing at 1, 2, and 3 years of follow-up were 83.3%, 95.8%, 92.8%, and 86.7%, 87.5% and 85.7%, respectively.

CONCLUSIONS

Proactive and serial monitoring of serum TNF inhibitor levels may make it possible for patients to maintain clinical remission and mucosal healing in the maintenance phase, with individualised optimization of the required dosage and minimization of secondary loss of response.

Treatment escalation and de-escalation decisions in Crohn's disease: Delphi consensus recommendations from Japan, 2021

BACKGROUND

We aimed to develop criteria for treatment intensification in patients with (1) luminal Crohn's disease (CD), (2) CD with perianal disease and/or fistula, (3) CD with small bowel stenosis, (4) in the postoperative setting, and (5) for discontinuing or reducing the dose of treatment in patients with CD.

METHODS

PubMed and Embase were searched for studies published since 1998 which may be relevant to the five defined topics. Results were assessed for relevant studies, with preference given to data from randomized, controlled studies. For each question, a core panel of 12 gastroenterologists defined the treatment target and developed statements, based on the literature, current guidelines, and relevant additional studies. The evidence supporting each statement was graded using the Oxford Centre for Evidence-Based Medicine: Levels of Evidence (March 2009). A modified Delphi process was used to refine statements and gain agreement from 54 Japanese specialists at in-person and online meetings conducted between October 2020 and April 2021.

RESULTS

Seventeen statements were developed for treatment intensification in luminal CD (targeting endoscopic remission), six statements for treatment intensification in perianal/fistulizing CD (targeting healing of perianal lesions and complete closure of the fistula), six statements for treatment intensification in CD with small bowel stenosis (targeting resolution of obstructive symptoms), seven statements for treatment intensification after surgery (targeting endoscopic remission), and five statements for discontinuing or reducing the dose of treatment in patients with CD.

CONCLUSIONS

These statements provide guidance on how and when to intensify or de-intensify treatment for a broad spectrum of patients with CD.

Multi-utility of therapeutic drug monitoring in inflammatory bowel diseases

Inflammatory bowel disease (IBD) treatment targets have progressed over time from clinical response to clinical and endoscopic remission. Several data have shown a positive correlation between serum biologic drug concentrations and favorable therapeutic outcomes. Therapeutic drug monitoring (TDM) has evolved as an important approach for optimizing the use of immunobiologics, especially antitumor necrosis factor therapy, in patients with IBD. The use of TDM is supported by medical societies and IBD experts in different contexts; however, challenges remain due to knowledge gaps that limit the widespread use of it. The aim of this review is to assess the role of TDM in IBD, focusing on the implementation of this strategy in different scenarios and demonstrating the multi-utility aspects of this approach in clinical practice.

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.

The Impact of Intermediate Antidrug Antibodies to Infliximab and Adalimumab on Clinical Outcomes in Patients with Crohn’s Disease or Ulcerative Colitis

Background: The anti-TNF drugs adalimumab (ADA) and infliximab (IFX) are effective treatments for inflammatory bowel disease (IBD). However, 40% of patients lose response, often due to the development of antibodies-to-ADA (ATA) and antibodies-to-IFX (ATI). While low ATA/ATI titres (<200 ng/mL) are associated with better outcomes and high ATA/ATI titres (>1,000 ng/mL) are associated with poorer outcomes, the significance of intermediate ATA/ATI titres (200–999 ng/mL) is not well understood. This study aims to investigate the impact of intermediate ATA/ATI titres on outcomes in patients with IBD. Methods: A retrospective chart review of 376 patients with IBD was conducted. The primary clinical outcome was persistence on anti-TNF therapy for 1 year after the measurement of ATA/ATI titres. The participants consisted of patients with IBD treated with IFX or ADA at the University of Maryland Medical Center’s Inflammatory Bowel Disease Program between October 2016 and October 2019. Results: Out of 322 patients with low titres, 271 persisted on their original anti-TNF, compared with nine out the 15 patients with intermediate titres (p=0.026) and one out the 10 patients with high titres (p<0.0001). The odds ratio of persistence when comparing intermediate titres to low titres was 0.26 (0.09–0.80), and when comparing high titres to low titres was 0.02 (0.00–0.14). Conclusion: Patients with intermediate titres were more likely to lose response to anti-TNF drugs and require a change in anti-TNF therapy than patients with low titres. Although the sample size of patients with intermediate titres was small, providers should consider dose optimisation of anti-TNF drugs, with or without the addition of an immunosuppressant, when intermediate titres are present.

Objective disease activity assessment and therapeutic drug monitoring prior to biologic therapy changes in routine inflammatory bowel disease clinical practice: TARGET-IBD

BACKGROUND

Inflammatory bowel disease (IBD) treatment paradigms recommend objective disease activity assessment and reactive therapeutic drug monitoring (TDM) prior to changes in biologic therapy. We aimed to describe objective marker and TDM assessment in routine clinical practice prior to biologic therapeutic changes in adult IBD patients.

METHODS

TARGET-IBD is a prospective longitudinal cohort of over 2100 IBD patients receiving usual care at 34 US academic or community centers enrolled between June 2017 and October 2019 who received biologic therapy and had a dose change or biologic discontinuation for lack of efficacy. Objective markers of disease activity within 12 weeks prior included fecal calprotectin, C-reactive protein (CRP), endoscopy, computed tomography (CT) and magnetic resonance imaging (MRI). TDM data for infliximab or adalimumab was obtained.

RESULTS

525 patients (71.4% Crohn's disease [CD], 28.6% ulcerative colitis [UC]) receiving biologic therapy underwent dose change (55.6%) or discontinuation (44.4%) for lack of efficacy. The majority were Caucasian (85.7%), 18-39 years old (52.2%), privately insured (81.5%), and at academic centers (73.7%). For dose changes, 67.5% had at least one objective disease activity assessment or TDM in the 12 weeks prior (CD 67.9%, UC 66.2%; P = 0.79). The most common objective marker was CRP in both CD (39.1%) and UC (54.5%). CRP and calprotectin were used significantly more in UC (P = 0.02 and P = 0.03). TDM was obtained in 30.7% (28.8% UC, 31.4% CD; P = 0.72) prior to dose change. For biologic discontinuation, 79.4% patients underwent objective assessment or TDM prior. In CD, CRP (46.3%) was most common, and CT (P = 0.03) and MRI (P < 0.001) were significantly more frequent than in UC. TDM was performed in 40.1% of patients (43.5% UC, 38.0% CD, P = 0.49) prior to discontinuation. Among all participants with dose change or discontinuation, endoscopy was performed in 29.3% with CD and 31.3% with UC. Academic care setting was associated with objective assessment before therapy change (OR 1.59, 95% CI 1.01-2.50).

CONCLUSION

Nearly one-third of patients undergoing a biologic dose change or discontinuation do not undergo objective disease activity assessment or TDM. Assessment choice differs by disease. Future studies assessing the impact of such practices on long-term outcomes are needed.

Systematic review and meta-analysis: evaluating response to empiric anti-TNF dose intensification for secondary loss of response in Crohn's disease

INTRODUCTION

Anti-tumor necrosis factor (TNF) dose intensification represents an effective method of overcoming secondary loss of response (LOR); however, a subset of patients may not respond (tertiary non-response), or fail to demonstrate durable response (tertiary LOR) to intensified dosing. This systematic review and meta-analysis aimed to evaluate these outcomes to determine the clinical effectiveness of empiric dose intensification in Crohn's disease.

METHODS

Multiple databases including MEDLINE and EMBASE were interrogated to identify studies that reported outcomes following anti-TNF dose intensification to address secondary LOR in Crohn's disease. Studies that used anti-TNF levels as the primary basis for dose intensification were excluded. Studies that reported (1) tertiary response and tertiary non-response within 6 months or (2) tertiary response and tertiary LOR beyond 6 months, were pooled using a random effects model with risk ratio (RR) derived, quantifying the effect of each comparison.

RESULTS

Twenty-six studies reported outcomes following anti-TNF dose intensification to address secondary LOR. Short-term response within 12 weeks of any dose-intensification strategy was 33-90%, while sustained response (⩾48 weeks) was achieved in 25-85%. Tertiary non-response occurred in up to 45% of intensified patients within 6 months of anti-TNF dose intensification, while tertiary LOR beyond 6 months occurred in up to 64% of patients. Tertiary response was more likely than tertiary non-response within 6 months (RR 2.58, 95% CI (1.76, 3.79), I ² = 82%, 12 studies), while sustained response beyond 6 months compared to tertiary LOR (RR 1.10 (0.75, 1.61) I ² = 85%, 7 studies) was less convincing.

CONCLUSION

Although anti-TNF dose intensification is clinically effective in patients with Crohn's disease, particularly within the first 6 months, a proportion of patients will fail to demonstrate short-term and/or sustained clinical response. Hence, clinical reassessment following anti-TNF dose intensification, particularly beyond 6 months, remains important to differentiate between effective and ineffective dose-intensification strategies.

Current status and future perspectives on the use of therapeutic drug monitoring of thiopurine metabolites in patients with inflammatory bowel disease

INTRODUCTION

Despite new treatment options for inflammatory bowel disease (IBD), conventional thiopurines remain a common treatment option for maintaining remission, particularly in non-Westernized countries. Therapeutic drug monitoring (TDM) is advised in standard care for optimizing therapy strategies to improve effectiveness, reveal nonadherence and reduce toxicity. Still, the rationale of TDM is debated.

AREAS COVERED

Key insights on TDM of thiopurine metabolites are discussed. The pharmacology of thiopurines is described, emphasizing the interindividual differences in pharmacogenetics, pharmacokinetics and pharmacodynamics. Pharmacological differences between conventional thiopurines and tioguanine are outlined. Finally, several optimization strategies for thiopurine therapy in IBD are discussed.

EXPERT OPINION

TDM has been a useful, but limited, tool to individualize thiopurine therapy. Pharmacokinetic data on the active thiopurine metabolites, derived from measurements in erythrocytes, associated with clinical response only partially predict effectiveness and toxicity. An additional pharmacodynamic marker, such as Rac1/pSTAT3 expression in leukocytes, may improve applicability of TDM in the future.

Systematic review: efficacy of escalated maintenance anti-tumour necrosis factor therapy in Crohn's disease

BACKGROUND

Loss of response to anti-TNF agents is a common clinical problem. Dose escalation may be effective for reestablishing clinical response in Crohn's disease (CD).

AIMS

To perform a systematic review assessing the efficacy of escalated maintenance anti-TNF therapy in CD.

METHODS

EMBASE, MEDLINE, Web of Science, and CENTRAL databases were searched for English language publications through to April 25, 2021. Full-text articles evaluating escalated maintenance treatment (infliximab or adalimumab) in adult CD patients were included.

RESULTS

A total of 4733 records were identified, and 68 articles met eligibility criteria. Rates of clinical response (33%-100%) and remission (15%-83%) after empiric dose escalation for loss of response to standard anti-TNF therapy were high but varied across studies. Dose intensification strategies (doubling the dose versus shortening the therapeutic interval) were similarly efficacious. Dose-escalated patients tended to have higher serum drug levels compared to those on standard dosing. An exposure-response relationship following dose escalation was found in a number of observational studies. Randomised controlled trials comparing therapeutic drug monitoring (TDM) to empiric treatment intensification have failed to reach their primary end-points. Strategies including Bayesian dashboard-dosing and early treatment escalation targeting biomarker normalisation were found to be associated with improved long-term outcomes.

CONCLUSIONS

Empiric escalation of maintenance anti-TNF therapy can recapture clinical response in a majority of patients with secondary loss of response to standard maintenance doses. Proactive optimisation of maintenance dosing might prolong time to loss of response in some patients.

Therapeutic Drug Monitoring of Tumor Necrosis Factor Antagonists in Crohn Disease: A Theoretical Construct to Apply Pharmacokinetics and Guidelines to Clinical Practice

Therapeutic drug monitoring (TDM) is the measurement of drug and antidrug antibody concentrations in individuals to guide treatment decisions. In patients with Crohn disease (CD), TDM, used either reactively or proactively, is emerging as a valuable tool for optimization of tumor necrosis factor (TNF) antagonist therapy. Reactive TDM is carried out in response to treatment failure, whereas proactive TDM involves the periodic monitoring of patients responding to TNF antagonist therapy to allow treatment optimization. In patients with CD, most of the available data for TDM relate to the first-to-market TNF antagonist infliximab and, to a lesser extent, to adalimumab and certolizumab pegol. Several gastroenterology associations, including the American Gastroenterology Association, have endorsed the use of reactive TDM in patients with active CD. However, fewer recommendations currently exist for the use of proactive TDM, although several new prospective randomized controlled trials evaluating proactive TDM strategies have been published. In this review, the current evidence for reactive and proactive TDM is discussed, and a proactive treatment algorithm for certolizumab pegol based on previously published threshold concentrations is proposed.

Frequency and Effectiveness of Empirical Anti-TNF Dose Intensification in Inflammatory Bowel Disease: Systematic Review with Meta-Analysis

Loss of response to antitumor necrosis factor (anti-TNF) therapies in inflammatory bowel disease occurs in a high proportion of patients. Our aim was to evaluate the loss of response to anti-TNF therapy, considered as the need for dose intensification (DI), DI effectiveness and the possible variables influencing its requirements. Bibliographical searches were performed.

SELECTION

prospective and retrospective studies assessing DI in Crohn's disease and ulcerative colitis patients treated for at least 12 weeks with an anti-TNF drug.

EXCLUSION CRITERIA

studies using anti-TNF as a prophylaxis for the postoperative recurrence in Crohn's disease or those where DI was based on therapeutic drug monitoring.

DATA SYNTHESIS

effectiveness by intention-to-treat (random effects model). Data were stratified by medical condition (ulcerative colitis vs. Crohn's disease), anti-TNF drug and follow-up.

RESULTS

One hundred and seventy-three studies (33,241 patients) were included. Overall rate of the DI requirement after 12 months was 28% (95% CI 24-32, I2 = 96%, 41 studies) in naïve patients and 39% (95% CI 31-47, I2 = 86%, 18 studies) in non-naïve patients. The DI requirement rate was higher both in those with prior anti-TNF exposure (p = 0.01) and with ulcerative colitis (p = 0.02). The DI requirement rate in naïve patients after 36 months was 35% (95% CI 28-43%; I2 = 98%; 18 studies). The overall short-term response and remission rates of empirical DI in naïve patients were 63% (95% CI 48-78%; I2 = 99%; 32 studies) and 48% (95% CI: 39-58%; I2 = 92%; 25 studies), respectively. The loss of response to anti-TNF agents-and, consequently, DI-occurred frequently in inflammatory bowel disease (approximately in one-fourth at one year and in one-third at 3 years). Empirical DI was a relatively effective therapeutic option.

CRITICAL ANALYSIS OF ANTI-TNF USE IN THE ERA OF NEW BIOLOGICAL AGENTS IN INFLAMMATORY BOWEL DISEASE

BACKGROUND

Inflammatory bowel diseases (IBD), both Crohn's disease and ulcerative colitis, are chronic immune-mediated diseases that present a relapsing and remitting course and requires long-term treatment. Anti-tumor necrosis factor (anti-TNF) therapy has changed the management of the disease by reducing the need for hospitalizations, surgeries and improving patient´s quality of life.

OBJECTIVE

The aim of this review is to discuss the role of anti-TNF agents in IBD, highlighting the situations where its use as first-line therapy would be appropriate.

METHODS

Narrative review summarizing the best available evidence on the topic based on searches in databases such as MedLine and PubMed up to April 2020 using the following keywords: "inflammatory bowel disease'', "anti-TNF agents" and ''biologic therapy''.

CONCLUSION

Biological therapy remains the cornerstone in the treatment of IBD. In the absence of head-to-head comparisons, the choice of the biological agent may be challenging and should take into account several variables. Anti-TNF agents should be considered as first line therapy in specific scenarios such as acute severe ulcerative colitis, fistulizing Crohn's disease and extra-intestinal manifestations of IBD, given the strong body of evidence supporting its efficacy and safety in these situations.

Is Therapeutic Drug Monitoring for Anti-tumour Necrosis Factor Agents in Adults With Inflammatory Bowel Disease Ready for Standard of Care? A Systematic Review and Meta-analysis

INTRODUCTION

Using therapeutic drug monitoring [TDM] in adult patients with inflammatory bowel disease [IBD] remains controversial. We conducted a systematic review and meta-analysis to answer four clinical PICO [Population, Intervention, Comparator, Outcome] questions.

METHODS

We searched MEDLINE, Embase, Web of Science, and Cochrane Central from inception to June 30, 2019. Remission was defined by the manuscripts' definitions of clinical remission. Data were analysed using RevMan 5.3. Quality of evidence was assessed with GRADE methodology.

RESULTS

We identified and screened 3365 abstracts and 11 articles. PICO 1 Reactive vs No TDM: six studies pooled showed 57.1% [257/450] failed to achieve remission following reactive TDM vs 44.7% [268/600] in the no TDM group (risk ratio [RR]: 1.14; 95% confidence interval [CI] 0.88-1.47). PICO 2 Proactive vs no TDM: five studies pooled showed 19.5% [75/384] failed to maintain remission in the proactive TDM group vs 33.4% [248/742] in the no TDM group [RR: 0.60; 95% CI 0.35-1.04]. PICO 3 Proactive vs Reactive TDM: two retrospective studies pooled showed 14.2% [26/183] failure to maintain remission in the proactive TDM group and 64.7% [119/184] in the reactive TDM group [RR: 0.22; 95% CI 0.15-0.32]. PICO 4 TDM [proactive/reactive] vs No TDM: we pooled 10 studies showing 39.7% [332/837] failed to achieve remission in the TDM [proactive/reactive] cohort vs 40.3% [428/1063] in the no TDM cohort [RR: 0.94; 95% CI 0.77-1.14]. Overall, the quality of evidence in each PICO was very low when using GRADE.

CONCLUSIONS

This meta-analysis shows that data supporting use of TDM in adults are limited and of very low quality. Further well-designed randomized controlled trials are needed to determine the place of TDM in clinical practice.

Therapeutic thresholds and mechanisms for primary non-response to infliximab in inflammatory bowel disease

BACKGROUND

Primary non-response to infliximab (IFX) inherits a poor prognosis in inflammatory bowel disease (IBD). We explored underlying mechanisms and therapeutic thresholds in an effort to provide basis for optimizing therapy.

METHODS

A prospectively followed cohort of 166 IBD patients having received standard IFX induction therapy (5 mg/kg at weeks 2, 6, and 14) had trough IFX and anti-IFX antibodies (Abs) retrospectively assessed at weeks 2 (n = 148) and 6 (n = 108). Circulating TNFα was measured in matched primary non-responders (n = 29) and responders (n = 21) at baseline and weeks 6 and 14. Clinical outcome at week 14 was supported by disease activity scores in half of patients.

RESULTS

In all, 18 patients (11%) had primary non-response. Infliximab was consistently lower throughout the induction phase in non-responders as compared to responders (Week 2: IFX median 18.9 μg/mL vs. 23.3, p < .05. Week 6: 8.4 vs. 17.0, p < .05). Optimal IFX thresholds associated with response was 22.9 μg/mL at week 2 (sensitivity 51%, specificity 80%, AUC_ROC 0.67, p < .05) and 11.8 at week 6 (72%, 77%, 0.71, p < .05). Anti-IFX Abs occurred in 28% of primary non-responders and associated with low IFX and treatment failure (OR 13.7 [2.8-67.5], p < .01). Markers of disease activity (disease activity scores, albumin, CRP) also associated with low IFX. Circulating TNFα was higher throughout induction in non-responders with ulcerative colitis but not Crohn's disease.

CONCLUSION

IBD patients with primary IFX failure generally have lower IFX trough than responders during early induction phase. Pharmacokinetic failure seems common in ulcerative colits, whereas pharmacodynamic failure appears common in Crohn's disease.

The effect of early trough level of infliximab on subsequent disease course in patients with Crohn disease: A prospective cohort study

Decreased trough level of infliximab (TLI) is associated with diminished efficacy in patients with Crohn disease (CD). We examined whether TLI at 14 weeks subsequent to the start of infliximab (IFX) treatment would impact long-term clinical course.Serum IFX levels and antibodies to IFX (ATI) at 14 and 54 weeks after IFX administration were measured in 12 patients with mild to moderate CD. We examined patient background, clinical severity, blood test values, and the relationship between ATI and TLI up to 108 weeks.We compared the group with TLI < 3 μg/mL at 14 weeks (TLI(14) < 3 group) the group with TLI > 3 μg/mL (TLI(14) ≥ 3 group). Patients in the TLI(14) ≥ 3 group were significantly more likely to use immunomodulators before IFX treatment induction (P = .01). At 54 weeks, 2 cases of ATI production were observed in the TLI(14) < 3 group, but no ATI production was observed in the TLI(14) ≥ 3 group. TLI in the TLI(14) ≥ 3 group at 54 weeks was significantly higher than in the TLI(14) < 3 group (6.5 μg/mL vs 1.0 μg/mL; P < .01). Although CD activity index and serum albumin values in the TLI(14) ≥ 3 group at 14, 54, and 108 weeks significantly improved compared to baseline, these improvements were not observed in the TLI(14) < 3 group. The remission maintenance rate at 108 weeks evaluated with the Kaplan-Meier method was significantly higher in the TLI(14) ≥ 3 group than the TLI(14) < 3 group (100% vs 33.3%; P = .02).The TLI 14 weeks after IFX treatment in patients with CD affects long-term outcome.

Clinical Pharmacokinetic and Pharmacodynamic Considerations in the Treatment of Ulcerative Colitis

Ulcerative colitis (UC) is an inflammatory bowel disease (IBD) of unknown etiology, probably caused by a combination of genetic and environmental factors. The treatment of patients with active UC depends on the severity, localization and history of IBD medication. According to the classic step-up approach, treatment with 5-aminosalicylic acid compounds is the first step in the treatment of mild to moderately active UC. Corticosteroids, such as prednisolone are used in UC patients with moderate to severe disease activity, but only for remission induction therapy because of side effects associated with long-term use. Thiopurines are the next step in the treatment of active UC but monotherapy during induction therapy in UC patients is not preferred because of their slow onset. Therapeutic drug monitoring (TDM) of the pharmacologically active metabolites of thiopurines, 6-thioguanine nucleotide (6-TGN), has proven to be beneficial. Thiopurine S-methyltransferase (TMPT) plays a role in the metabolic conversion pathway of thiopurines and exhibits genetic polymorphism; however, the clinical benefit and relevance of TPMT genotyping is not well established. In patients with severely active UC refractory to corticosteroids, calcineurin inhibitors such as ciclosporin A (CsA) and tacrolimus are potential therapeutic options. These agents usually have a rather rapid onset of action. Monoclonal antibodies (anti-tumor necrosis factor [TNF] agents, vedolizumab) are the last pharmacotherapeutic option for UC patients before surgery becomes inevitable. Body weight, albumin status and antidrug antibodies contribute to the variability in the pharmacokinetics of anti-TNF agents. Additionally, the use of concomitant immunomodulators (thiopurines/methotrexate) lowers the rate of immunogenicity, and therefore the concomitant use of anti-TNF therapy with an immunomodulator may confer some advantage compared with monotherapy in certain patients. TDM of anti-TNF agents could be beneficial in patients with primary nonresponse and secondary loss of response. The potential benefit of applying TDM during vedolizumab treatment has yet to be determined.

Outcomes and Strategies to Support a Treat-to-target Approach in Inflammatory Bowel Disease: A Systematic Review

BACKGROUND AND AIMS

Management of Crohn's disease and ulcerative colitis has typically relied upon treatment intensification driven by symptoms alone. However, a 'treat-to-target' management approach may help to address underlying inflammation, minimise disease activity at early stages of inflammatory bowel disease, limit progression, and improve long-term outcomes.

METHODS

A systematic literature review was conducted to identify data relevant to a treat-to-target approach in inflammatory bowel disease, published between January 1, 2007 and May 15, 2017.

RESULTS

Consistent with recommendations of the Selecting Therapeutic Targets in Inflammatory Bowel Disease [STRIDE] working group, studies have investigated factors influencing the achievement of both endoscopic and histological mucosal healing and patient-level outcomes in inflammatory bowel disease [IBD]. Histological healing and biomarker levels have also been shown to be modifiable outcomes. Although there is a lack of prospectively derived evidence validating mucosal healing as a treatment target, data are emerging to suggest that targeting mucosal healing or inflammation rather than symptoms may be cost-effective in some settings. The review highlighted several strategies that may support the implementation of a treat-to-target approach in IBD. The prospective randomised CALM study demonstrated how tight control [whereby treatment decisions are based on close monitoring of inflammatory biomarkers] leads to improvements in endoscopic and clinical outcomes. The review also considered the influence of coordinated care from a multidisciplinary team and patient engagement with improved adherence, as well as the role of therapeutic drug monitoring in inflammatory bowel disease management.

CONCLUSIONS

A treat-to-target strategy may impact on disease progression and improve outcomes in inflammatory bowel disease. Prospective studies including long-term data are required to ensure that the most appropriate targets and strategies are identified.

Model-Based Therapeutic Drug Monitoring of Infliximab Using a Single Serum Trough Concentration

BACKGROUND AND OBJECTIVES

The pharmacokinetics of infliximab are highly variable and influence clinical response in chronic inflammatory diseases. The goal of this study was to build a Bayesian model allowing predictions of upcoming infliximab concentrations and dosing regimen adjustment, using only one concentration measurement and information regarding the last infliximab infusion.

METHODS

This retrospective study was based on data from 218 patients treated with infliximab in Tours University Hospital who were randomly assigned to learning (two-thirds) or validation (one-third) data subsets. One-compartment pharmacokinetic and time since last dose (TLD) models were built and compared using learning and validation subsets. From these models, Bayesian pharmacokinetic and TLD models using one concentration measurement (1C-PK and 1C-TLD) were designed. The predictive performances of the 1C-TLD model were tested on two external validation cohorts.

RESULTS

Pharmacokinetic and TLD models described the data satisfactorily and provided accurate parameter estimations. Comparable predictions of infliximab concentrations were obtained from pharmacokinetic versus TLD models, as well as from Bayesian 1C-PK versus 1C-TLD models. The 1C-TLD model showed satisfactory prediction of future infliximab concentrations and provided satisfactory predictions of infliximab steady-state concentration for up to three upcoming visits after a blood sample.

CONCLUSIONS

Accurate individual concentration predictions can be obtained using a single infliximab concentration measurement and information regarding only the last infusion. The 1C-TLD model may help to optimize the dosing regimen of infliximab in routine therapeutic drug monitoring.

Systematic Review: Cost-effective Strategies of Optimizing Anti-tumor Necrosis and Immunomodulators in Inflammatory Bowel Disease

BACKGROUND

Medication costs in inflammatory bowel disease (IBD) are now the principal driver of health care costs. Cost-effective strategies to optimize and rationalize treatment are therefore necessary.

METHODS

A systematic review until April 30, 2018, was performed to identify economic evaluations of strategies to optimize infliximab, adalimumab, and immunomodulators for the treatment of IBD in adults. A qualitative synthesis of the identified studies was performed.

RESULTS

Seventy articles were identified that met the inclusion criteria. Adalimumab seems cost-effective compared with infliximab as maintenance therapy for moderate to severe Crohn's disease (CD). Infusion costs are a significant additional treatment cost with infliximab. However, other studies found biosimilar infliximab more cost-effective than alternative biologics in fistulizing and moderate-severe luminal CD-although the latter did not reach a willingness-to-pay threshold of <$50,000. In moderate-severe ulcerative colitis, infliximab seems more cost-effective than adalimumab. Multiple tailored approaches to treatment based on objective markers of disease activity or efficacy have been shown to be cost-effective in CD, including following secondary loss of response to anti-TNF therapy for postoperative recurrence and in escalating treatment. For immunomodulator treatment, both thiopurine methyltransferase (TPMT) testing before commencing thiopurines and thiopurine metabolite testing for dose optimization seem cost-effective.

CONCLUSION

In a win-win for patients and payers, several potential avenues to achieve cost-effectiveness-but also therapeutic optimization of anti-TNF therapies-were elucidated in this review with comparatively sparse data for immunomodulators. Optimizing immunomodulator and anti-tumor necrosis factor alpha therapy to achieve objective disease control seems to be cost-effective at conventional willingness-to-pay thresholds in a number of clinical settings.

Canadian Association of Gastroenterology Clinical Practice Guideline for the Medical Management of Pediatric Luminal Crohn's Disease

BACKGROUND & AIMS

We aim to provide guidance for medical treatment of luminal Crohn's disease in children.

METHODS

We performed a systematic search of publication databases to identify studies of medical management of pediatric Crohn's disease. Quality of evidence and strength of recommendations were rated according to the GRADE (Grading of Recommendation Assessment, Development, and Evaluation) approach. We developed statements through an iterative online platform and then finalized and voted on them.

RESULTS

The consensus includes 25 statements focused on medical treatment options. Consensus was not reached, and no recommendations were made, for 14 additional statements, largely due to lack of evidence. The group suggested corticosteroid therapies (including budesonide for mild to moderate disease). The group suggested exclusive enteral nutrition for induction therapy and biologic tumor necrosis factor antagonists for induction and maintenance therapy at diagnosis or at early stages of severe disease, and for patients failed by steroid and immunosuppressant induction therapies. The group recommended against the use of oral 5-aminosalicylate for induction or maintenance therapy in patients with moderate disease, and recommended against thiopurines for induction therapy, corticosteroids for maintenance therapy, and cannabis in any role. The group was unable to clearly define the role of concomitant immunosuppressants during initiation therapy with a biologic agent, although thiopurine combinations are not recommended for male patients. No consensus was reached on the role of aminosalicylates in treatment of patients with mild disease, antibiotics or vedolizumab for induction or maintenance therapy, or methotrexate for induction therapy. Patients in clinical remission who are receiving immunomodulators should be assessed for mucosal healing within 1 year of treatment initiation.

CONCLUSIONS

Evidence-based medical treatment of Crohn's disease in children is recommended, with thorough ongoing assessments to define treatment success.

Canadian Association of Gastroenterology Clinical Practice Guideline for the Medical Management of Pediatric Luminal Crohn's Disease

BACKGROUND & AIMS

We aim to provide guidance for medical treatment of luminal Crohn's disease in children.

METHODS

We performed a systematic search of publication databases to identify studies of medical management of pediatric Crohn's disease. Quality of evidence and strength of recommendations were rated according to the GRADE (Grading of Recommendation Assessment, Development, and Evaluation) approach. We developed statements through an iterative online platform and then finalized and voted on them.

RESULTS

The consensus includes 25 statements focused on medical treatment options. Consensus was not reached, and no recommendations were made, for 14 additional statements, largely due to lack of evidence. The group suggested corticosteroid therapies (including budesonide for mild to moderate disease). The group suggested exclusive enteral nutrition for induction therapy and biologic tumor necrosis factor antagonists for induction and maintenance therapy at diagnosis or at early stages of severe disease, and for patients failed by steroid and immunosuppressant induction therapies. The group recommended against the use of oral 5-aminosalicylate for induction or maintenance therapy in patients with moderate disease, and recommended against thiopurines for induction therapy, corticosteroids for maintenance therapy, and cannabis in any role. The group was unable to clearly define the role of concomitant immunosuppressants during initiation therapy with a biologic agent, although thiopurine combinations are not recommended for male patients. No consensus was reached on the role of aminosalicylates in treatment of patients with mild disease, antibiotics or vedolizumab for induction or maintenance therapy, or methotrexate for induction therapy. Patients in clinical remission who are receiving immunomodulators should be assessed for mucosal healing within 1 year of treatment initiation.

CONCLUSIONS

Evidence-based medical treatment of Crohn's disease in children is recommended, with thorough ongoing assessments to define treatment success.

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.

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.

Inductively coupled plasma mass spectrometry assay for quantification of free infliximab in serum

TNF antagonists such as infliximab are effective for the treatment of several inflammatory and autoimmune diseases. Recent clinical studies have advocated the importance of measuring trough infliximab levels to guide treatment decisions. We have developed a novel assay for measuring serum free infliximab levels using inductively coupled plasma-mass spectrometry (ICP-MS). The method involves the incubation of patient serum in wells coated with recombinant TNF, followed by detection with lanthanide-labeled monoclonal anti-human IgG1 and ICP-MS analysis. Full method validation was performed and results for clinical samples tested with the new method were compared with those obtained from a capture ELISA and a cell-based assay. Validation of the ICP-MS assay revealed a lower limit of detection of 0.4 μg/mL in serum. The linear range of quantitation was 1-50 μg/mL. The within-run and between-run precision had a coefficient of variation (CV) of <10%, and the accuracy of the assay had a CV of <15%. In serum samples, the ICP-MS method was devoid of analytical interferences by high levels of hemoglobin, bilirubin and triglycerides. Serum sample results from 123 drug-naïve donors revealed a test cutoff at 0.5 μg/mL. Test results from clinical samples obtained by the ICP-MS method showed strong correlation with both the ELISA and cell-based assay. The ICP-MS methodology presented in this study is a robust method for measuring TNF antagonist serum levels, which makes it well suited for therapeutic drug monitoring in the clinical laboratory.

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.

A value proposition for trough level-based anti-TNFα drug dosing

Treatment of inflammatory bowel diseases and rheumatic disorders with anti-tumor necrosis factor alpha (TNFα) drugs is expensive, while a significant proportion of patients does not show adequate clinical response. Therapeutic drug monitoring (TDM) enables patient-specific anti-TNFα therapy. The role of laboratory tests in clinical care has recently been described in a value proposition framework. It describes care processes, stakeholders, costs, risks, benefits and patient outcomes based on the use of a laboratory test in a clinical care pathway. We have applied this concept to the use of TDM for anti-TNFα drugs, describing evidence that supports the intervention and its cost effectiveness, steps that need to be adjusted in the care pathway, possible treatment algorithms and measures to assess adoption of this framework into clinical practice. For effective TDM, an assay for measurement of drug levels together with appropriate target ranges and an anti-drug-antibody assay have to be implemented. Also, instead of only reporting the drug concentration, laboratorians, pharmacists and clinicians should deliver added value by introducing a TDM-based treatment algorithm into clinical practice. Thus, to maximize effectiveness of TDM of anti-TNFα therapy in routine care, adjustment of current care pathways and cooperation of many stakeholders are needed.

Clinical Outcomes With Therapeutic Drug Monitoring in Inflammatory Bowel Disease: A Systematic Review With Meta-Analysis

BACKGROUND AND AIMS

We undertook a systematic review and meta-analysis examining the effectiveness of therapeutic drug monitoring [TDM] to improve clinical outcomes in inflammatory bowel disease patients treated with anti-tumour necrosis factor alpha [anti-TNF] drugs.

METHODS

We searched MEDLINE, Epub Ahead of Print, EMBASE and Cochrane up to October 2017 for randomized trials [RCTs] and cohort studies comparing proactive or reactive TDM to each other or empiric care. Outcomes included clinical remission [primary], clinical relapse, endoscopic remission, anti-TNF response durability, cost and adverse events [secondary]. Pooled odds ratios and mean differences were calculated.

RESULTS

The search identified nine studies [three RCTs, six observational], focused on infliximab maintenance therapy in adults. Neither proactive nor reactive TDM was associated with superior clinical remission rates compared to empiric dose optimization. However, evidence of a cost benefit, particularly for reactive TDM vs empiric care, was identified. In several studies, TDM, particularly proactive TDM, was associated with favourable outcomes related to durability of anti-TNF response, such as lower drug discontinuation rates compared to empiric care and reactive TDM, and lower relapse rates compared to empiric care. No consistent benefit was found for endoscopic or surgical outcomes.

CONCLUSIONS

The existing limited evidence does not support an association between any TDM strategy and superior clinical remission rates but does support a cost savings benefit [particularly for reactive TDM] and suggests a potential benefit for anti-TNF durability [particularly proactive TDM]. Additional, longer-term studies are needed, particularly to further investigate proactive TDM, and to generate data on other anti-TNF agents, the induction period and paediatric populations.

Economic Evaluations of Treatments for Inflammatory Bowel Diseases: A Literature Review

OBJECTIVE

The objective of this literature review was to evaluate the existing evidence regarding the cost-effectiveness of treatment options in IBD.

METHODS

A systematic review of the literature was conducted to identify economic evaluations of IBD therapy. The literature search was performed using electronic databases MEDLINE and EMBASE. Searches were limited to full economic evaluations published in English or French between 2004 and 2016.

RESULTS

A total of 5,403 potentially relevant studies were identified. After screening titles and abstracts, 48 studies were included, according to the eligibility criteria. A total of 56% and 42% of the studies were assessing treatments of UC or CD, respectively. Treatment options under evaluation included biological agents, mesalamine, immunosuppressants, and surgery. The majority of studies evaluated the cost-effectiveness of biological treatments. Biological therapies were dominant in 23% of the analyses and were cost-effective according to a $CAD50,000/QALY and $CAD100,000/QALY threshold in 41% and 62% of the analyses, respectively.

CONCLUSION

This literature review provided a comprehensive overview of the economic evaluations for the different treatment options for IBD over the past 12 years and represents a helpful reference for future economic evaluations.

Proactive Infliximab Monitoring Following Reactive Testing is Associated With Better Clinical Outcomes Than Reactive Testing Alone in Patients With Inflammatory Bowel Disease

BACKGROUND AND AIMS

Reactive testing has emerged as the new standard of care for managing loss of response to infliximab in inflammatory bowel disease [IBD]. Recent data suggest that proactive infliximab monitoring is associated with better therapeutic outcomes in IBD. Nevertheless, there are no data regarding the clinical utility of proactive infliximab monitoring after first reactive testing. We aimed to evaluate long-term outcomes of proactive infliximab monitoring following reactive testing compared with reactive testing alone in patients with IBD.

METHODS

This was a retrospective multicenter cohort study of consecutive IBD patients on infliximab maintenance therapy receiving a first reactive testing between September 2006 and January 2015. Patients were divided into two groups; Group A [proactive infliximab monitoring after reactive testing] and Group B [reactive testing alone]. Patients were followed through December 2015. Time-to-event analysis for treatment failure and IBD-related surgery and hospitalization was performed. Treatment failure was defined as drug discontinuation due to either loss of response or serious adverse event.

RESULTS

The study population consisted of 102 [n = 70, 69% with CD] patients [Group A, n = 33 and Group B, n = 69] who were followed for (median, interquartile range [IQR]) 2.7 [1.4-3.8] years. Multiple Cox regression analysis identified proactive following reactive TDM as independently associated with less treatment failure (hazard ratio [HR] 0.15; 95% confidence interval [CI] 0.05-0.51; p = 0.002) and fewer IBD-related hospitalizations [HR: 0.18; 95% CI 0.05-0.99; p = 0.007].

CONCLUSIONS

This study showed that proactive infliximab monitoring following reactive testing was associated with greater drug persistence and fewer IBD-related hospitalizations than reactive testing alone.

A Role for Thiopurine Metabolites in the Synergism Between Thiopurines and Infliximab in Inflammatory Bowel Disease

BACKGROUND

Interactions between principal cytotoxic thiopurine metabolites, that is 6-thioguanine nucleotides [6-TGN], and infliximab [IFX] and anti-IFX antibodies [Abs] may contribute to higher effectiveness of IFX-thiopurine combination therapy than monotherapies in inflammatory bowel disease.

METHODS

To examine if thiopurine metabolites influenced trough IFX and anti-IFX Abs, 89 patients previously assessed for anti-IFX Abs were included. To assess if IFX influenced thiopurine metabolites, eight patients who had responded to 12 weeks of intensified IFX at a constant thiopurine dosing were included.

RESULTS

In the first cohort, IFX-thiopurine combination therapy reduced anti-IFX Ab detection [8/40; 20%] as compared with IFX monotherapy [22/49; 45%], odds ratio [OR] 0.31 [0.12-0.80], p < 0.05. 6-TGN was significantly lower in anti-IFX Ab-positive patients (50 pmol/8 × 108 red blood cells [RBC] vs 105, p < 0.01). All anti-IFX Ab-positive patients had 6-TGN < 117 pmol/8 × 108 RBC (sensitivity 100% [63-100], specificity 47% [29-65], area under the curveROC = 0.82, p < 0.01). Trough IFX was similar between anti-IFX Ab-negative patients in IFX monotherapy and IFX-thiopurine combination therapy [5.1 μg/mL vs 4.9, p = 0.76]. 6-TGN and IFX did not correlate [rP = 0.04, p = 0.83; rS = 0.02, p = 0.89, respectively]. In the second cohort, trough IFX increased during IFX intensification [ΔIFX median 6.5 μg/mL, p = 0.02], but 6-TGN was stable [6-TGN at Weeks 0, 4, 8, 12: 90 pmol/8 × 108 RBC, 93, 101, 90; p > 0.05]. Methylated mercaptopurine metabolite associations were consistently negative.

CONCLUSIONS

Superior effect of IFX-thiopurine combination therapy over monotherapies partly relates to decrease in anti-IFX Abs, which associates with 6-TGN levels and has a lower therapeutic threshold than during thiopurine monotherapy. Additional benefit likely ascribes to synergy between different anti-inflammatory modes of action rather than direct drug interactions.

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.

Review article: consensus statements on therapeutic drug monitoring of anti-tumour necrosis factor therapy in inflammatory bowel diseases

BACKGROUND

Therapeutic drug monitoring (TDM) in inflammatory bowel disease (IBD) patients receiving anti-tumour necrosis factor (TNF) agents can help optimise outcomes. Consensus statements based on current evidence will help the development of treatment guidelines.

AIM

To develop evidence-based consensus statements for TDM-guided anti-TNF therapy in IBD.

METHODS

A committee of 25 Australian and international experts was assembled. The initial draft statements were produced following a systematic literature search. A modified Delphi technique was used with 3 iterations. Statements were modified according to anonymous voting and feedback at each iteration. Statements with 80% agreement without or with minor reservation were accepted.

RESULTS

22/24 statements met criteria for consensus. For anti-TNF agents, TDM should be performed upon treatment failure, following successful induction, when contemplating a drug holiday and periodically in clinical remission only when results would change management. To achieve clinical remission in luminal IBD, infliximab and adalimumab trough concentrations in the range of 3-8 and 5-12 μg/mL, respectively, were deemed appropriate. The range may differ for different disease phenotypes or treatment endpoints-such as fistulising disease or to achieve mucosal healing. In treatment failure, TDM may identify mechanisms to guide subsequent decision-making. In stable clinical response, TDM-guided dosing may avoid future relapse. Data indicate drug-tolerant anti-drug antibody assays do not offer an advantage over drug-sensitive assays. Further data are required prior to recommending TDM for non-anti-TNF biological agents.

CONCLUSION

Consensus statements support the role of TDM in optimising anti-TNF agents to treat IBD, especially in situations of treatment failure.

Application of Population Pharmacokinetic Modeling for Individualized Infliximab Dosing Strategies in Crohn Disease

OBJECTIVES

The pharmacokinetics of infliximab (IFX) is highly variable in children with Crohn disease (CD), and a one-size-fits-all approach to dosing is inadequate. Model-based drug dosing can help individualize dosing strategies. We evaluated the predictive performance and clinical utility of a published population pharmacokinetic model of IFX in children with CD.

METHODS

Within a cohort of 34 children with CD who had IFX trough concentrations measured, the pharmacokinetics of each patient was estimated in NONMEM using a published population pharmacokinetic model. Infliximab concentrations were then predicted based on each patient's dosing history and compared with actual measured concentrations (n = 59). In addition, doses 5 to 10 mg/kg and dosing intervals every 4 to 8 weeks were simulated in each patient to examine dose-trough relationships.

RESULTS

Predicted concentrations were within ±1.0 μg/mL of actual measured concentrations for 88% of measurements. The median prediction error (ie, measure of bias) was -0.15 μg/mL (95% confidence interval -0.37 to -0.05 μg/mL) and absolute prediction error (ie, measure of precision) was 0.26 μg/mL (95% confidence interval 0.15 to 0.40 μg/mL). At standard maintenance dosing of 5 mg/kg every 8 weeks, a trough >3 μg/mL was predicted to be achieved in 32% of patients. To achieve a trough >3 μg/mL, a dosing interval ≤every 6 weeks was predicted to be required in 29% of patients.

CONCLUSIONS

A published IFX population pharmacokinetic model demonstrated accurate predictive performance in a pediatric CD population. Individualized IFX dosing strategies in children with CD will be critical to consistently achieve trough concentrations associated with optimal outcomes.

Out-of-Pocket Cost Is a Barrier to Therapeutic Drug Monitoring in Inflammatory Bowel Disease

BACKGROUND

Therapeutic drug monitoring (TDM) is increasingly performed to optimize biologic therapy in inflammatory bowel disease (IBD). However, patients and physicians may be reluctant to perform TDM due to concerns related to potential out-of-pocket costs.

AIMS

The aim of this study was to evaluate patient understanding and attitudes toward TDM in different clinical scenarios with and without potential out-of-pocket costs.

METHODS

Adult IBD patients at a tertiary gastroenterology clinic were anonymously surveyed from March to September 2016 to assess their understanding of and willingness to undergo TDM in a variety of clinical scenarios, both with and without a potential out-of-pocket cost. Responses were analyzed for associations with changes in attitudes if out-of-pocket costs were involved.

RESULTS

Of 118 completed surveys, 68.2% of patients were aware of or had previously undergone TDM. Patient willingness to undergo TDM was high both with and without potential out-of-pocket costs (70 and 98%, respectively); however, patients were significantly less willing with out-of-pocket cost (p < 0.01). Higher disease-related quality of life scores, as measured by the short inflammatory bowel disease questionnaire (SIBDQ), was significantly associated with an increased willingness to assume a potential out-of-pocket cost (p = 0.007).

CONCLUSIONS

Overall, patients understand and are willing to undergo TDM in certain potentially beneficial clinical scenarios, however, are significantly less willing if paying out-of-pocket. A higher SIBDQ score was associated with an increase in willingness to undergo TDM when out-of-pocket cost was involved. Physicians should discuss TDM with their patients in order to make an informed and personalized treatment decision.

Dried blood spots from finger prick facilitate therapeutic drug monitoring of adalimumab and anti-adalimumab in patients with inflammatory diseases

AIMS

Development of a self-sampling method for therapeutic drug monitoring (TDM) of biologicals will enhance TDM implementation in routine care and pharmacokinetic knowledge. The aim of this study was to compare adalimumab and anti-adalimumab antibody (ADA) concentration measurements in dried blood spots (DBS) obtained from finger prick with measurements in serum obtained via venepuncture, from patients with rheumatic inflammatory diseases.

METHODS

In this cross-sectional study, 161 consecutive patients were included. For clinical validation, DBS from finger prick and serum from venepuncture were collected simultaneously and adalimumab and ADA concentration were assessed by ELISA and antigen binding test (ABT), respectively. To convert DBS eluate results to values which can be compared to serum concentrations, five different methods were investigated, using a marker protein or a volumetric approach.

RESULTS

Adalimumab and ADA concentrations obtained from the finger prick/DBS method correlated well with serum results from the same patient (correlation coefficient > 0.87). Interestingly, antibody concentrations (either adalimumab, ADA or total immunoglobulin G) in DBS from finger prick, but not albumin, were systematically lower compared to serum. Spike experiments demonstrated a quantitative recovery for all tested proteins in DBS, suggesting a slightly different protein composition of blood collected via finger prick vs. venepuncture. We established a correction factor to relate finger prick/DBS values with serum values (approximately 1.2).

CONCLUSIONS

We show here for the first time that adalimumab and ADA serum concentrations can be satisfactorily estimated by measuring concentrations in DBS eluates, collected by finger prick. This method offers great opportunity to simplify TDM of adalimumab.

Improved Long-term Outcomes of Patients With Inflammatory Bowel Disease Receiving Proactive Compared With Reactive Monitoring of Serum Concentrations of Infliximab

BACKGROUND & AIMS

Monitoring serum concentrations of tumor necrosis factor antagonists in patients receiving these drugs as treatment for inflammatory bowel disease (IBD), also called therapeutic drug monitoring, is performed either after patient loss of response (reactive drug monitoring) or in patients in clinical remission in which the drug is titrated to a target concentration (proactive drug monitoring). We compared long-term outcomes of patients with IBD undergoing proactive vs reactive monitoring of serum concentrations of infliximab.

METHODS

We performed a multicenter, retrospective study of 264 consecutive patients with IBD (167 with Crohn's disease) receiving infliximab maintenance therapy. The subjects received proactive (n = 130) or reactive (n = 134) drug monitoring, based on measurements of first infliximab concentration and antibodies to infliximab, from September 2006 to January 2015; they were followed through December 2015 (median time of 2.4 years). We analyzed time to treatment failure, first IBD-related surgery or hospitalization, serious infusion reaction, and detection of antibodies to infliximab. Treatment failure was defined as drug discontinuation for loss of response or serious adverse event, or need for surgery.

RESULTS

Multiple Cox regression analysis independently associated proactive drug monitoring, compared with reactive monitoring, with reduced risk for treatment failure (hazard ratio [HR], 0.16; 95% confidence interval [CI], 0.09-0.27; P < .001), IBD-related surgery (HR, 0.30; 95% CI, 0.11-0.80; P = .017), IBD-related hospitalization (HR, 0.16; 95% CI, 0.07-0.33; P < .001), antibodies to infliximab (HR, 0.25; 95% CI, 0.07-0.84; P = .025), and serious infusion reaction (HR, 0.17; 95% CI, 0.04-0.78; P = .023).

CONCLUSIONS

In a retrospective analysis of patients with IBD receiving proactive vs reactive monitoring of serum concentration of infliximab, proactive monitoring was associated with better clinical outcomes, including greater drug durability, less need for IBD-related surgery or hospitalization, and lower risk of antibodies to infliximab or serious infusion reactions.

Cost-effectiveness of drug monitoring of anti-TNF therapy in inflammatory bowel disease and rheumatoid arthritis: a systematic review

BACKGROUND

Therapeutic drug monitoring (TDM) of anti-TNF is increasingly used to manage inflammatory bowel diseases (IBD) and rheumatoid arthritis (RA). The cost-effectiveness of this strategy is debated.

METHODS

All studies comparing the cost-effectiveness of a TDM-based strategy and an empirical dose management of anti-TNF in IBD or RA were screened. Studies were identified through the MEDLINE electronic database (up to July 2016), and annual international meeting abstracts were also manually reviewed.

RESULTS

Seven studies were included: two randomized controlled trials (RCTs) enrolling 332 patients [247 Crohn's disease (CD) and 85 ulcerative colitis (UC)] and five modeling approaches. Four studies included only CD patients, one included both CD and UC patients, and two included only RA patients. Three studies compared the cost-effectiveness of the two strategies in patients with secondary infliximab (IFX) failure (dose-escalation strategy), one in patients in remission on optimized IFX (de-escalation strategy), one in patients starting adalimumab, and two in patients with clinical response to maintenance anti-TNF therapy. The two RCTs demonstrated that a TDM strategy led to major cost savings, ranging from 28 to 34 %. The three modeling approaches with regard to CD patients demonstrated cost savings ranging from $5396 over a 1-year period to €13,130 per patient at 5 years of follow-up. A TDM strategy also led to major cost savings in the two modeling approaches in RA patients.

CONCLUSIONS

Available evidence indicates that a TDM strategy leads to major cost savings related to anti-TNF therapy in both IBD and RA patients, with no negative impact on efficacy.

Therapeutic drug monitoring of anti-tumour necrosis factor-α agents in inflammatory bowel disease

INTRODUCTION

Anti-TNFα therapy has revolutionised treatment of inflammatory bowel disease, however primary non-response and secondary loss of response are a significant problem. Therapeutic drug monitoring (TDM) has recently emerged as a means of optimising use of anti-TNFα agents. Areas covered: TDM of anti-TNFα agents can guide clinical decisions during treatment failure events, prevent treatment failure events, and potentially result in significant healthcare cost saving. TDM for anti-TNFα agent involves measurement of drug levels and anti-drug antibodies, and can be performed reactively or proactively. Reactive TDM reserves testing for treatment failure events, while proactive TDM also consists of periodic TDM for patients responding to anti-TNFα therapy to allow treatment optimisation. Generation of anti-drug antibodies is recognised as one important mechanism of treatment failure and adverse events. Expert opinion: Evidence strongly supports TDM at time of treatment failure, while studies employing proactive TDM have demonstrated conflicting results. TDM can also help better select patients likely to remain in clinical remission on anti-TNFα treatment interruption. Currently TDM is used to optimise anti-TNFα treatment, but it is not used by most clinicians to prevent adverse reactions to anti-TNFα agents.

Biomarkers in Search of Precision Medicine in IBD

The completion of the human genome project in 2003 represented a major scientific landmark, ushering in a new era with hopes and expectations of fresh insights into disease mechanisms and treatments. In inflammatory bowel disease (IBD), many important discoveries soon followed, notably the identification of >200 genetic susceptibility loci and characterization of the gut microbiome. As "big data", driven by advances in technology, becomes increasingly available and affordable, individuals with IBD and clinicians alike yearn for tangible outcomes from the promise of "precision medicine"-precise diagnosis, monitoring, and treatment. Here, we provide a commentary on the prospects and challenges of precision medicine and biomarkers in IBD. We focus on the three key areas where precision IBD will have the most impact: (1) disease susceptibility, activity, and behavior; (2) prediction of drug response and adverse effects; and (3) identification of subphenotypic mechanisms to facilitate drug discovery and selection of new treatments in IBD.

Magnitude of Increased Infliximab Clearance Imposed by Anti-infliximab Antibodies in Crohn's Disease Is Determined by Their Concentration

Antibodies (Abs) against infliximab (IFX) increase IFX clearance and can result in treatment failure and acute hypersensitivity reactions. However, interpretation of their clinical value is complicated by individual differences in Ab responses and methods used for quantification. The increase in IFX clearance imposed by anti-IFX Abs has generally been evaluated using a binary classification, i.e., positive or negative. This analysis aimed to investigate if anti-IFX Ab concentrations provide a more adequate prediction of alterations in clearance. Data originated from a clinical trial on Crohn's disease patients with IFX treatment failure. The trial was not originally designed for pharmacokinetic analysis. Therefore, published pharmacokinetic models were utilized as priors to enable covariate investigation. The impact of anti-IFX Abs on clearance was assessed using different mathematical relationships and exploiting information from two different quantification assays, measuring semi-quantitative "total" or "unbound neutralizing" concentrations of anti-IFX Ab, respectively. Inclusion of anti-IFX Ab status/concentration improved the model's performance for all investigated relationships. The anti-IFX Ab concentrations were superior to the binary classifications, indicating that the magnitude of increase in IFX clearance imposed by anti-IFX Abs closely relates to their concentration. Furthermore, total anti-IFX Ab concentrations appeared superior to the unbound neutralizing fraction in identifying high clearance individuals. Simulations showed that even at low concentrations, anti-IFX Abs lead to sub-therapeutic IFX concentrations, supporting a need of treatment interventions in all anti-IFX Ab positive patients. The developed model can serve as a basis for further investigations to refine treatment recommendations for patients with anti-IFX Abs.

Therapeutic Drug Monitoring and Clinical Outcomes in Immune Mediated Diseases: The Missing Link

As the incidence of inflammatory bowel diseases and the number of patients treated with anti-TNF agents keep on increasing so are the phenomena of primary non response (PNR) and secondary loss of response (SLR) to these medications. Traditionally PNR and SLR have been managed empirically-that is, switching medications for PNR and increasing the anti-TNF dose for SNR. More recently an approach based on testing drug levels and antibodies to the drug (therapeutic drug monitoring) has gained increasing popularity in the management of inflammatory bowel diseases. However, while this strategy might offer an insight into the mechanisms leading to PNR/SLR it often falls short of providing a simple, reproducible method to manage these issues in clinical practice. Here, we will review the currently recommended therapeutic strategies when using therapeutic drug monitoring; the evidence for and against such approach and the current standard strategies in Rheumatology (the specialty with the largest and longest experience with anti-TNF agents). We will then discuss the possible reasons of the shortcomings of therapeutic drug monitoring and the rationale and need to move the therapeutic target to the disease burden in inflammatory bowel diseases-along with the supporting preliminary evidence. Finally, we will focus on future crucial studies that need to be done to make approaches to PNR/SLR more rigorous and at the same time user-friendly for the practicing gastroenterologist.