Adalimumab drug and antibody levels as predictors of clinical and laboratory response in patients with Crohn's disease

A Survey Study of Gastroenterologists' Attitudes and Barriers Toward Therapeutic Drug Monitoring of Anti-TNF Therapy in Inflammatory Bowel Disease

BACKGROUND

Therapeutic drug monitoring (TDM) may improve the efficacy and cost-effectiveness of anti-TNF therapy. A standardized approach of utilizing TDM has not been established. The objective of this study was to determine gastroenterologists' attitudes and barriers toward TDM of anti-TNF therapy in clinical practice.

METHODS

An 18-question survey was distributed to members of the American College of Gastroenterology and Crohn's and Colitis Foundation via email. We collected physician characteristics, practice demographics, and data regarding TDM use and perceived barriers to TDM. Factors associated with the use of TDM were determined by logistic regression analysis.

RESULTS

A total of 403 gastroenterologists from 42 US states (76.4% male) met inclusion criteria: 90.1% use TDM, mostly reactively for secondary loss of response (87.1%) and primary nonresponse (66%); 36.6% use TDM proactively. The greatest barriers to TDM implementation were uncertainty about insurance coverage (77.9%), high out-of-pocket patient costs (76.4%), and time lag from serum sample to result (38.5%). Factors independently associated with the use of TDM and proactive TDM were practice in an academic setting (P = 0.019), and more IBD patients seen per month (P = 0.015), and Crohn's and Colitis Foundation membership (P < 0.001), and more IBD patients on anti-TNF therapy per month (P = 0.006), respectively. If all barriers were removed, an additional one-third of physicians would apply proactive TDM.

CONCLUSIONS

Lack of insurance coverage, high out-of-pocket costs, and the time lag from test to result limit use of TDM in the United States. Validation of low-cost assays, point of care testing, and studies that standardize the use of TDM are needed to make TDM more commonplace.

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.

Significance of measurement of serum trough level and anti-drug antibody of adalimumab as personalised pharmacokinetics in patients with Crohn's disease: a subanalysis of the DIAMOND trial

BACKGROUND

Significance of monitoring adalimumab trough levels and anti-adalimumab antibodies (AAA) for disease outcome in Crohn's disease (CD) patients remained unclear.

AIM

To evaluate the association of adalimumab trough levels and AAA at week 26 with clinical remission at week 52, the effect of azathiopurine on AAA and factors influencing trough levels in CD patients in the DIAMOND trial.

METHODS

We performed this study using adalimumab trough levels, AAA at week 26 and 6-thioguanine nucleotide (TGN) in red blood cells at week 12. A multiple regression model and receiver operating analysis was performed to identify factors influencing adalimumab trough levels and AAA, and adalimumab thresholds for predicting disease activity.

RESULTS

There was a significant difference of adalimumab trough level at week 26 between patients with disease remission and without at week 52 (7.7 ± 3.3 μg/mL vs 5.4 ± 4.3 μg/mL: P <.001). Adalimumab trough level of 5.0 μg/mL yielded optimal sensitivity and specificity for remission prediction (80.2% and 55.6%, respectively). AAA development at week 26 significantly affected remission at week 52 (P = .021), which was strongly associated with adalimumab trough levels. Female gender and increasing body weight were independently associated with low adalimumab trough levels, and female gender was associated with AAA development. A cut-off 6TGN level of >222.5 p mol/8 ×108 RBCs yielded sensitivity (100%) and specificity (60.6%) for AAA negativity.

CONCLUSION

Adalimumab trough levels and AAA occurrence were significantly associated with clinical remission. Higher 6TGN affected AAA negativity. The combination therapy is beneficial in some relevant aspects for CD patients. (UMIN Registration No. 000005146).

Can We Predict the Efficacy of Anti-TNF-α Agents?

The use of biologic agents, particularly anti-tumor necrosis factor (TNF)-α, has revolutionized the treatment of inflammatory bowel diseases (IBD), modifying their natural history. Several data on the efficacy of these agents in inducing and maintaining clinical remission have been accumulated over the past two decades: their use avoid the need for steroids therapy, promote mucosal healing, reduce hospitalizations and surgeries and therefore dramatically improve the quality of life of IBD patients. However, primary non-response to these agents or loss of response over time mainly due to immunogenicity or treatment-related side-effects are a frequent concern in IBD patients. Thus, the identification of predicting factors of efficacy is crucial to allow clinicians to efficiently use these therapies, avoiding them when they are ineffective and eventually shifting towards alternative biological therapies with the end goal of optimizing the cost-effectiveness ratio. In this review, we aim to identify the predictive factors of short- and long-term benefits of anti-TNF-α therapy in IBD patients. In particular, multiple patient-, disease- and treatment-related factors have been evaluated.

Clinical usefulness of serum antibodies as biomarkers of gastrointestinal and liver diseases

The progressively growing knowledge of the pathophysiology of a number of immune-mediated gastrointestinal and liver disorders, including autoimmune atrophic gastritis, coeliac disease, autoimmune enteropathy, inflammatory bowel disease, autoimmune hepatitis, primary sclerosing cholangitis, primary biliary cholangitis and autoimmune pancreatitis, together with the improvement of their detection methods have increased the diagnostic power of serum antibodies. In some cases - coeliac disease and autoimmune atrophic gastritis - they have radically changed gastroenterologists' diagnostic ability, while in others - autoimmune hepatitis, inflammatory bowel disease and autoimmune pancreatitis - their diagnostic performance is still inadequate. Of note, serum antibody misuse in clinical practice has raised a number of controversies, which may generate confusion in the diagnostic management of the aforementioned disorders. In this review, we critically re-evaluate the usefulness of serum antibodies as biomarkers of immune-mediated gastrointestinal and liver disorders, and discuss their pitfalls and merits.

American Gastroenterological Association Institute Technical Review on the Role of Therapeutic Drug Monitoring in the Management of Inflammatory Bowel Diseases

Therapeutic drug monitoring (TDM), which involves measurement of drug or active metabolite levels and anti-drug antibodies, is a promising strategy that can be used to optimize inflammatory bowel disease therapeutics. It is based on the premise that there is a relationship between drug exposure and outcomes, and that considerable inter-individual variability exists in how patients metabolize the drug (pharmacokinetics) and the magnitude and duration of response to therapy (pharmacodynamics). Therefore, the American Gastroenterological Association has prioritized clinical guidelines on the role of TDM in the management of inflammatory bowel disease. To inform these clinical guidelines, this technical review was developed in accordance with the GRADE (Grading of Recommendations Assessment, Development, and Evaluation) framework for interventional and prognostic studies, and focused on the application of TDM for biologic therapy, specifically anti-tumor necrosis factor-α agents, and for thiopurines. Focused questions address the benefits and risks of a strategy of reactive TDM (in patients with active inflammatory bowel disease) to guide treatment changes compared with empiric treatment changes, and the benefits and risks of a strategy of routine proactive TDM (during routine clinical care in patients with quiescent disease) compared with no routine TDM. Additionally, the review addresses the benefits and risks of routine measurement of thiopurine methyltransferase enzyme activity or genotype before starting thiopurine therapy compared with empiric weight-based dosing and explores the performance of different trough drug concentrations for anti-tumor necrosis factor agents and thiopurines to inform clinical decision making when applying TDM in a reactive setting. Due to a paucity of data, this review does not address the role of TDM for more recently approved biologic agents, such as vedolizumab or ustekinumab.

Effects of Combination Therapy With Immunomodulators on Trough Levels and Antibodies Against Tumor Necrosis Factor Antagonists in Patients With Inflammatory Bowel Disease: A Meta-analysis

BACKGROUND & AIMS

It is not clear whether combination therapy with immunomodulators affects the immunogenicity of tumor necrosis factor (TNF) antagonists in patients with inflammatory bowel disease. We performed a meta-analysis to quantify the effects of combined immunomodulator therapy on the presence of antibodies against TNF antagonists (antidrug antibodies [ADAs]) and trough levels of anti-TNF agents.

METHODS

We systematically searched publication databases for studies that reported prevalence of ADAs in patients who received anti-TNF agents. Raw data from studies that met the inclusion criteria were pooled to determine effect estimates. We performed subgroup and metaregression analyses to determine the level of heterogeneity among study outcomes.

RESULTS

We analyzed findings from 35 studies that met inclusion criteria (results reported from 6790 patients with inflammatory bowel disease). The pooled risk ratio for formation of ADAs in patients receiving combined therapy with immunomodulators, versus that of patients receiving anti-TNF monotherapy, was 0.49 (95% confidence interval, 0.41-0.59; P < .001). However, the pooled analysis did not demonstrate a significant difference in trough levels of anti-TNF agents between patients with versus without concurrent use of immunomodulators (standardized mean difference, 0.11; 95% confidence interval, 0.19-0.41; P = .47). Subgroup analyses of patients treated with different TNF antagonists revealed no difference in the formation of ADAs (P = .50 for interaction); the protective effect of immunomodulators did not differ with type of drug patients were given (methotrexate vs thiopurines), or assay for ADA. We observed heterogeneity only among studies of patients with ulcerative colitis (I² = 76%). Funnel plot and Egger test analyses indicated publication bias in the studies (P = .001).

CONCLUSIONS

In a meta-analysis of published studies, we associated combined treatment with immunomodulators with reduced risk of formation of antibodies against TNF antagonists in patients with inflammatory bowel disease.

Update on Therapeutic Drug Monitoring in Crohn's Disease

In patients with Crohn's disease on biologic medications, the use of therapeutic drug monitoring leads to a personalized approach to optimize treatment. Using an algorithmic approach, measurement of drug concentrations and anti-drug antibodies can be used to improve treatment outcomes. Therapeutic drug concentrations and absence of antibodies are associated with improved clinical and endoscopic outcomes. In clinical practice, therapeutic drug monitoring has been shown to be clinically useful and cost-effective in patients experiencing a loss of response to treatment. This review highlights the available data on therapeutic drug monitoring in the treatment of patients with Crohn's disease on biologic medications.

Development and validation of an optical biosensor for rapid monitoring of adalimumab in serum of patients with Crohn's disease

Therapeutic drug monitoring of adalimumab is recommended to improve therapeutic outcome in patients with Crohn's disease. Performing an ELISA requires a rather long time-to-result and the necessity of collecting multiple samples to decrease the cost per adalimumab determination. In this study, we aim to develop and validate a rapid assay suitable for measuring a single adalimumab serum sample using a fiber-optic surface plasmon resonance (FO-SPR) based sensor. Therefore, we have immobilized MA-ADM28B8 as capture antibody on an FO-probe and conjugated MA-ADM40D8 as detecting antibody to gold nanoparticles. A dose-response curve ranging from 2.5 to 40 ng/mL adalimumab was obtained in 1/400 diluted serum. Serum samples of patients with adalimumab concentrations between 1 and 16 μg/mL were measured whereas the negative control, a sample spiked with infliximab at a concentration of 16 μg/mL, showed no significant signal. Using a pre-functionalized FO-probe, the technology requires less than 45 minutes for measuring a single sample. Comparison of measurements between the biosensor and the ELISA revealed an excellent agreement with a Pearson r coefficient of 0.99 and an intra-class coefficient of 0.99. The reduced assay time and the possibility of measuring a single sample are major advantages compared to the ELISA. The developed and validated optical adalimumab biosensor could be a valuable point-of-care diagnostic tool for adalimumab quantification in patients with Crohn's disease.

Drug persistence and need for dose intensification to adalimumab therapy; the importance of therapeutic drug monitoring in inflammatory bowel diseases

BACKGROUND

Therapeutic drug monitoring (TDM) aid therapeutic decision making in patients with inflammatory bowel disease (IBD) who lose response to anti-TNF therapy. Our aim was to evaluate the frequency and predictive factors of loss of response (LOR) to adalimumab using TDM in IBD patients.

METHODS

One hundred twelve IBD patients (with 214 TDM measurements, CD/UC 84/28, male/female 50/62, mean age CD/UC: 36/35 years) were enrolled in this consecutive cohort from two referral centres in Hungary. Demographic data were comprehensively collected and harmonized monitoring strategy was applied. Previous and current therapy, laboratory data and clinical activity were recorded at the time of TDM. Patients were evaluated either at the time of suspected LOR or during follow-up. TDM measurements were determined by commercial ELISA (LISA TRACKER, Theradiag, France).

RESULTS

Among 112 IBD patients, LOR/drug persistence was 25.9%/74.1%. The cumulative ADA positivity (>10 ng/mL) and low TL (<5.0 μg/mL) was 12.1% and 17.8% after 1 year and 17.3% and 29.5% after 2 years of adalimumab therapy. Dose intensification was needed in 29.5% of the patients. Female gender and ADA positivity were associated with LOR (female gender: p < 0.001, OR:7.8 CI 95%: 2.5-24.3, ADA positivity: p = 0.007 OR:3.6 CI 95%: 1.4-9.5).

CONCLUSIONS

ADA development, low TL and need for dose intensification were frequent during adalimumab therapy and support the selective use of TDM in IBD patients treated with adalimumab. ADA positivity and gender were predictors of LOR.

Strategies for overcoming anti-tumor necrosis factor drug antibodies in inflammatory bowel disease: Case series and review of literature

Anti-tumor necrosis factor (TNF) biologics are currently amongst the most widely used and efficacious therapies for inflammatory bowel disease (IBD). The development of therapeutic drug monitoring for infliximab and adalimumab has allowed for measurement of drug levels and antidrug antibodies. This information can allow for manipulation of drug therapy and prediction of response. It has been shown that therapeutic anti-TNF drug levels are associated with maintenance of remission, and development of antidrug antibodies is predictive of loss of response. Studies suggest that a low level of drug antibodies, however, can at times be overcome by dose escalation of anti-TNF therapy or addition of an immunomodulator. We describe a retrospective case series of twelve IBD patients treated at the University of California-Irvine, who were on infliximab or adalimumab therapy and were found to have detectable but low-level antidrug antibodies. These patients underwent dose escalation of the drug or addition of an immunomodulator, with subsequent follow-up drug levels obtained. Eight of the twelve patients (75%) demonstrated resolution of antidrug antibodies, and were noted to have improvement in disease activity. Though data regarding overcoming low-level anti-TNF drug antibodies remains somewhat limited, cases described in the literature as well as our own experience suggest that this may be a viable strategy for preserving the use of an anti-TNF drug. Low-level anti-TNF drug antibodies may be overcome by dose escalation and/or addition of an immunomodulator, and can allow for clinical improvement in disease status. Therapeutic drug monitoring is an important tool to guide this strategy.

Serum Adalimumab Levels Predict Successful Remission and Safe Deintensification in Inflammatory Bowel Disease Patients in Clinical Practice

BACKGROUND

Little is known about the association between the pharmacokinetic features of adalimumab (ADL) and disease outcome in patients with inflammatory bowel disease (IBD).

AIMS

To assess the association between random serum ADL levels and clinical or biochemical remission with clinical decision making in daily practice according to these levels; and to determine the cutoff value for successful dose reduction in patients with IBD treated with ADL.

METHODS

We conducted a prospective observational study of patients with IBD who received long-term maintenance therapy with ADL.

RESULTS

Data were available for 157 serum samples from 87 patients. Serum ADL levels were associated with clinical remission: median 9.2 versus 6.0 μg/mL for patients with Crohn's disease with active disease (P = 0.009) and 14.4 versus 5.2 μg/mL in patients with ulcerative colitis with active disease (P = 0.002). Serum ADL levels were 9.2 μg/mL for patients with a normal C-reactive protein value (<5 mg/L) and 5.2 μg/mL for patients with a high C-reactive protein value (P = 0.002). ADL levels were significantly associated with normal fecal calprotectin value (<80 ng/g) (10.8 versus 7.6 μg/mL, respectively, P = 0.038). Serum ADL levels were significantly associated with successful deintensification, over a 6-month period of clinical follow-up, compared with the group in which doses remained unchanged (area under the curve 0.88; 95% confidence interval, 0.81-0.95; P < 0.001), with a cutoff value for successful deintensification of 12.2 μg/mL.

CONCLUSIONS

Higher ADA levels were significantly associated with clinical and biochemical remission. Our results, which were obtained under conditions of daily clinical practice, suggest that an ADL cutoff of 12.2 μg/mL could be appropriate for successful dose reduction in patients with IBD treated with ADL.

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.

Infliximab and adalimumab drug levels in Crohn's disease: contrasting associations with disease activity and influencing factors

BACKGROUND

Discriminative drug level thresholds for disease activity endpoints in patients with Crohn's disease. have been consistently demonstrated with infliximab, but not adalimumab.

AIMS

To identify threshold concentrations for infliximab and adalimumab in Crohn's disease according to different disease endpoints, and factors that influence drug levels.

METHODS

We performed a cross-sectional service evaluation of patients receiving maintenance infliximab or adalimumab for Crohn's disease. Serum drug levels were at trough for infliximab and at any time point for adalimumab. Endpoints included Harvey-Bradshaw index, C-reactive protein and faecal calprotectin. 6-tioguanine nucleotide (TGN) concentrations were measured in patients treated with thiopurines.

RESULTS

A total of 191 patients (96 infliximab, 95 adalimumab) were included. Differences in infliximab levels were observed for clinical (P=.081) and biochemical remission (P=.003) and faecal calprotectin normalisation (P<.0001) with corresponding thresholds identified on ROC analysis of 1.5, 3.4 and 5.7 μg/mL. Adalimumab levels were similar between active disease and remission regardless of the endpoint assessed. Modelling identified that higher infliximab dose, body mass index and colonic disease independently accounted for 31% of the variation in infliximab levels, and weekly dosing, albumin and weight accounted for 23% of variation in adalimumab levels. TGN levels did not correlate with drug levels.

CONCLUSIONS

Infliximab drug levels are associated with the depth of response/remission in patients with Crohn's disease, but no such relationship was observed for adalimumab. More data are needed to explain the variation in drug levels.

Effects of Transient and Persistent Anti-drug Antibodies to Certolizumab Pegol: Longitudinal Data from a 7-Year Study in Crohn's Disease

BACKGROUND

Anti-drug antibodies (ADAbs) may decrease the efficacy of biologics and increase the risk of adverse events. A single positive test may not preclude further treatment because of variations in assays used, test timing, and patient variables. We evaluated the longitudinal patterns of immunogenicity during 7 years of antitumor necrosis factor-alpha drug certolizumab pegol (CZP) treatment for moderate-to-severe Crohn's disease.

METHODS

PRECiSE 3 patients (n = 595) received open-label CZP 400 mg every 4 weeks up to 7 years. CZP-ADAb expression, plasma CZP concentration, Harvey-Bradshaw Index, C-reactive protein, and fecal calprotectin concentrations were measured multiple times. Longitudinal data, examined for CZP-ADAb positivity and categorized as transient (with temporary/no effect on CZP concentration), persistent, or negative, were correlated with clinical and biological variables.

RESULTS

Of the CZP-ADAb-positive patients, 40 (22.6%) had transient CZP-ADAbs and 94 (77.4%) had persistent CZP-ADAbs. Demographic characteristics were similar between groups. Median C-reactive protein and fecal calprotectin were higher (P < 0.05 at some visits) and plasma CZP concentrations were significantly lower (P < 0.0001 at all visits) in the persistent CZP-ADAb-positive group relative to the CZP-ADAb-negative group. Transient CZP-ADAb-positive and CZP-ADAb-negative patients had similar plasma CZP, C-reactive protein, and fecal calprotectin concentrations. Median Harvey-Bradshaw Index scores and rates of adverse events were similar among groups.

CONCLUSIONS

This analysis demonstrates that persistent CZP-ADAb has negative effects on drug levels and efficacy, whereas transient expression may not. Serial measurements may be needed to characterize ADAb positivity. www.clinicaltrials.gov, Number NCT00160524.

Therapeutic Drug Monitoring of Golimumab in the Treatment of Ulcerative Colitis

Ulcerative colitis (UC) is a relapsing-remitting chronic inflammatory disorder affecting the mucosal surface in a continuous manner from the rectum through part of, or the entire, colon. Patients with severe disease and those who become refractory or intolerant to corticosteroids and/or immunosuppressants, require treatment with biologic agents that target tumor necrosis factor-α (TNF). Golimumab, a fully human monoclonal antibody, is the latest TNF antagonist to get approved for the treatment of moderate-to-severe UC. Subcutaneously administered golimumab induces and maintains clinical response, remission, and mucosal healing. Serum concentrations of golimumab are associated with response to therapy, as patients with higher drug exposure are more likely to achieve these outcomes. Since various patient and disease-related factors were shown to influence the pharmacokinetics of TNF antagonists, drug exposure may be variable over time and between patients, affecting success of therapy. A major contributing factor is immunogenicity, with development of anti-drug antibodies (ADAb) and an accelerated clearance of drug as a result. Although there is a growing body of evidence to support therapeutic drug monitoring (TDM) for infliximab and adalimumab, two other TNF antagonists, only limited data is available for golimumab. In addition, the clinically important drug exposure thresholds are not widely known, which has limited the use of TDM for golimumab in clinical practice. This review summarizes available data regarding the use of golimumab for UC, with emphasis on the pharmacokinetics, exposure-response relationship, and the role of TDM in optimizing therapy.

Intra-patient variability in adalimumab drug levels within and between cycles in Crohn's disease

BACKGROUND

Whether therapeutic drug monitoring for adalimumab needs to be performed at trough has not been defined.

AIM

To determine intra-patient adalimumab drug-level variation and to identify modulating patient and disease factors.

METHODS

In this prospective observational study, adult patients with Crohn's disease established on maintenance adalimumab had drug levels measured repeatedly according to pre-defined schedules (visit 1: day 4-6, visit 2: day 7-9, trough: day 13-14) across two consecutive fortnightly cycles. Disease activity was assessed using Harvey-Bradshaw Index, C-reactive protein and faecal calprotectin. For this analysis, trough levels ≥4.9 μg/mL were considered therapeutic.

RESULTS

Nineteen patients underwent 111 evaluations. Mean intra-patient drug levels from paired visits between cycles did not differ (visit1 cycle1: 4.81, cycle2: 5.21 μg/mL, P = 0.24, visit2 cycle1: 4.86, cycle2: 4.82, P = 0.91 and trough cycle1: 3.95, cycle2: 3.95, P = 0.99), irrespective of disease activity. Drug levels were stable over the first 9 days (visit 1-2), but declined to trough by a mean 1.06 and 0.89 μg/mL between visit 1 or 2, respectively (P < 0.001). Models using nontemporal factors (smoking, syringe delivery device) and levels at earlier visits accounted for 66-80% of the variance in trough levels. On receiver-operating curve analysis, thresholds identified in the first 9 days that predicted a therapeutic trough level were similar to the trough threshold itself, with high sensitivity but modest specificity.

CONCLUSION

While therapeutic drug monitoring should be performed at trough, a drug level ≥4.9 μg/mL obtained during the first 9 days predicts a therapeutic trough drug level with reasonable confidence.

Dose de-escalation to adalimumab 40 mg every 3 weeks in patients with Crohn's disease - a nested case-control study

BACKGROUND

Data on dose de-escalation in patients with Crohn's disease (CD) are limited.

AIM

To evaluate outcomes of dose de-escalation from adalimumab (ADM) every other week (EOW) to every three weeks (ETW).

METHODS

We selected patients with CD receiving maintenance therapy with ADM 40 mg ETW with serum levels (SL) available before and after dose de-escalation. Sex- and age-matched controls continuing ADM 40 mg EOW were identified. Patient reported outcome, C-reactive protein (CRP) and serum albumin were collected.

RESULTS

Out of 898 patients, we identified 40 (11 male, median 37 years) who de-escalated to ADM 40 mg ETW for ADM-related adverse events (AE, n = 1), ADM SL >7 μg/mL (n = 8), or both (n = 31). Compared to controls, ADM SL dropped significantly within 4 months, without associated clinical or biochemical changes. In 53% of patients, dose de-escalation was associated with disappearance of AE (8/16 skin manifestation, 3/6 arthralgia, 5/7 frequent infectious episodes). During a median follow-up of 24 months, 65% of patients maintained clinical response, but 35% needed dose escalation back to ADM 40 mg EOW because of clinical relapse (n = 8), ADM SL <4 μg/mL (n = 2), or both (n = 4). CRP <3.5 mg/L at dose de-escalation was independently associated with dose escalation-free survival [odds ratio 6.28 (95% CI 1.83-21.59), P = 0.004]. We could not define a minimal ADM SL to consider or maintain dose de-escalation.

CONCLUSIONS

Overall, 65% of patients who de-escalated to adalimumab 40 mg every 3 weeks remained in clinical remission for a median of 24 months. In 53% of patients, adalimumab-related adverse events disappeared after dose de-escalation. Regardless of adalimumab SL, disease remission should be assessed objectively prior to dose de-escalation.

Management Strategies to Improve Outcomes of Patients With Inflammatory Bowel Diseases

Strategies for management of inflammatory bowel diseases are shifting from simple control of symptoms toward full control of these diseases (clinical and endoscopic remission), with the final aim of blocking their progression and preventing bowel damage and disability. New goals have been proposed for treatment, such as treat to target and tight control based on therapeutic monitoring and early intervention. For patients who achieve clinical remission, there is often interest in discontinuation of therapy due to safety or economic concerns. We review the evidence supporting these emerging paradigms, the reasons that early effective treatment can alter progression of inflammatory bowel diseases, the importance of examining objective signs of inflammation, and the safety of reducing treatment dosage. We also discuss recent findings regarding personalization of care, including factors that predict patient outcomes and response to therapies, as well as preventative strategies.

Concurrent immunomodulator therapy is associated with higher adalimumab trough levels during scheduled maintenance therapy

INTRODUCTION

Combination therapy with infliximab and immunomodulators is superior to monotherapy, resulting in better outcomes and higher trough levels of infliximab. The role of concurrent immunomodulatory therapy on adalimumab trough levels has not been adequately investigated. We evaluated the impact of concomitant immunomodulation on adalimumab trough levels in patients on scheduled maintenance therapy.

METHOD

We conducted a prospective observational, cross-sectional study of all inflammatory bowel disease patients on maintenance therapy who had adalimumab trough levels measured between January 2013 and January 2016. Drug level and anti-drug antibody measurements were performed on sera using a solid phase assay. Pairwise comparison of means was used to compare trough levels in patients with and without concomitant immune modulator therapy.

RESULTS

In total, 79 patients were included. Twenty-three patients (29.1%) were on weekly dosing whereas 56 (70.9%) were on alternate weeks. Median adalimumab trough levels were comparable in patients with and without clinical remission (6.8 μg/ml (IQR 5.6-8.1) versus 6.7 μg/ml (IQR 3.9-8.1), respectively. Patients with an elevated faecal calprotectin >250 μg/g had lower adalimumab trough levels (median 6.7, IQR 3.9-8) compared to patients with faecal calprotectin <250 μg/g (median 7.7, IQR 6.1-8.1) though this did not achieve statistical significance (p = .062). Median adalimumab trough levels among patients on concurrent immunomodulators was 7.2 μg/ml (IQR 5.7-8.1) compared to those not on concurrent immunomodulator, 6.1 μg/ml (IQR 2.7-7.7, p = .0297).

CONCLUSION

Adalimumab trough levels were significantly higher in patients on concurrent immunomodulators during maintenance therapy. There was a trend towards a lower adalimumab trough level in patients with elevated calprotectin.

Addition of an immunomodulator can reverse antibody formation and loss of response in patients treated with adalimumab

BACKGROUND

Anti-adalimumab antibodies (AAA) are associated with loss of clinical response (LOR). Addition of an immunomodulator has been shown to reverse immunogenicity and regain response with infliximab monotherapy. Similar data on adalimumab are lacking.

AIM

To study the impact of immunomodulator addition on the emergence of AAA and LOR among adalimumab therapy patients.

METHODS

The databases of three tertiary medical centres were reviewed to identify patients who developed AAA during adalimumab monotherapy with resultant LOR, and received an immunomodulator as a salvage combination therapy. All sera were prospectively analysed using previously described ELISA assays. Clinical response was determined using appropriate clinical scores. Elimination of AAA, designated as 'sero-reversal', elevation of drug levels and regained clinical response were the sought outcomes.

RESULTS

Twenty-three patients (21 Crohn's disease, and 2 ulcerative colitis) developed AAA with subsequent LOR and were thereafter prescribed an immunomodulator as salvage therapy (thiopurine n = 14, methotrexate n = 9). Eleven patients (48%) underwent sero-reversal with gradual elimination of AAA, increase in drug trough levels and restoration of clinical response (median time to sero-reversal 5 months). In 12 patients (52%), immunogenicity and loss of response could not be reversed. There was no difference between responders and nonresponders in the type of immunomodulators used or baseline clinical characteristics.

CONCLUSIONS

In almost half of inflammatory bowel disease patients developing anti-adalimumab antibodies and loss of response, established immunogenicity of adalimumab can be gradually reversed by the addition of immunomodulator therapy with restoration of a clinico-biological response. However, these observations need to be confirmed with larger studies.

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.

Use of anti-TNF drug levels to optimise patient management

Anti-tumour necrosis factor (TNF) therapies, such as infliximab, adalimumab, certolizumab pegol and golimumab, have been proven to be effective for the treatment of patients with Crohn's disease and ulcerative colitis. However, 10%-30% of patients with inflammatory bowel disease (IBD) show no initial clinical benefit to anti-TNF therapy (primary non-response), and over 50% after an initial favourable outcome will lose response over time (secondary loss of response (SLR)). Numerous recent studies in IBD have revealed an exposure-response relationship suggesting a positive correlation between high serum anti-TNF concentrations and favourable therapeutic outcomes including clinical, biomarker and endoscopic remission, whereas antidrug antibodies have been associated with SLR and infusion reactions. Currently, therapeutic drug monitoring (TDM) is typically performed when treatment failure occurs either for SLR, drug intolerance (potential immune-mediated reaction) or infusion reaction (reactive TDM). Nevertheless, recent data demonstrate that proactive TDM and a treat-to-target (trough) therapeutic approach may more effectively optimise anti-TNF therapy efficacy, safety and cost. However, implementing TDM in real-life clinical practice is currently limited by the diversity in study design, therapeutic outcomes and assays used, which have hindered the identification of robust clinically relevant concentration thresholds. This review will focus mainly on the pharmacodynamic properties of anti-TNF therapy and the role of TDM in guiding therapeutic decisions in IBD.

Appropriateness of Testing for Anti-Tumor Necrosis Factor Agent and Antibody Concentrations, and Interpretation of Results

BACKGROUND & AIMS

The availability of tests for blood concentrations of anti-tumor necrosis factor (TNF) agents and antibodies against these drugs could improve dose selection for patients with inflammatory bowel disease (IBD). However, there is little consensus on when to test and how to interpret test results. We used the RAND/UCLA Appropriateness Method to determine when these tests are appropriate and how to clinically interpret their results.

METHODS

We conducted a systematic literature search in November 2013 to identify observational or experimental studies of the measurement of anti-TNF drug and antibody concentrations in patients with IBD and interpretation of their results. We developed 35 scenarios that assessed the appropriateness of testing and 143 scenarios that addressed clinical strategies in response to test results, and presented the findings to an expert panel. The appropriateness of each scenario was rated before and after an in-person meeting with the panel. Panelists rated the appropriateness of various clinical management options including changing therapy within class, switching out of class, adjusting drug dose or interval, adding or adjusting concomitant immune modulators, and doing nothing for each of 6 permutations of high versus low drug concentrations and high, low, or undetectable antibody concentrations. Disagreement was assessed using a validated index.

RESULTS

Assessment of anti-TNF drug and antibody concentrations was rated appropriate at the end of induction therapy in primary nonresponders, in secondary nonresponders, at least once during the first year of maintenance therapy, and following a drug holiday. Routine assessment in responders at the end of induction was rated uncertain. In nearly all scenarios, escalation of drug dosing was rated appropriate when drug concentration was low in the absence of antibodies, and switching within class was rated appropriate when antibodies were present. Other recommendations depended on the specific clinical scenario for which the test was obtained.

CONCLUSIONS

Based on the RAND/UCLA Appropriateness Method of analysis, an expert panel recommends testing for drug and antibody concentrations in many clinical scenarios. The appropriate timing and best way to respond to anti-TNF drug and antibody testing for IBD depends on the specific clinical scenario. These recommendations can help guide clinicians to best optimize anti-TNF therapy.

Adalimumab trough serum levels and anti-adalimumab antibodies in the long-term clinical outcome of patients with Crohn's disease

OBJECTIVE

Few data are available on the relevance of adalimumab (ADA) trough serum levels and anti-ADA antibodies (AAA) during long-term follow-up of patients with Crohn's Disease (CD), and their association with disease outcome. In this study, our aim was to assess ADA trough serum levels and the presence of AAA according to disease activity and clinical response during long-term follow-up in a series of patients with CD treated with ADA monotherapy.

MATERIAL AND METHODS

We prospectively evaluated 23 consecutive, infliximab-naïve CD patients who achieved clinical remission/response after induction and were in maintenance treatment with ADA, and who were followed-up for at least 72 weeks. Blood samples were drawn at standardized time points to assess ADA through levels, AAA.

RESULTS

At week 48, we found significantly (p = 0.027) different ADA trough serum levels in patients in remission (10.1 mcg/mL), mild (7.4 mcg/mL), and moderate/severe disease (4.5 mcg/mL). Median ADA trough levels were significantly lower in patients with AAA (3.7 mcg/mL versus 9.3 mcg/mL, p = 0.006). At the end of follow-up (median 102 weeks, range 73-112 weeks), ADA trough serum concentrations were significantly higher (11.9 mcg/mL) as compared to patients with mild and moderate/severe disease (5.5 mcg/mL, p = 0.0002). Furthermore, median ADA trough concentrations showed a trend towards lower levels in AAA positive patients (5.2 mcg/mL versus 7.2 mcg/mL, p = 0.371).

CONCLUSIONS

Our results emphasize the relevance of therapeutic drug monitoring in CD patients on biologic treatment. ADA trough serum levels and the presence of AAA are important features in the management of patients on ADA treatment.

A Systematic Review on Infliximab and Adalimumab Drug Monitoring: Levels, Clinical Outcomes and Assays

BACKGROUND

Immunogenicity to therapeutic proteins has been linked to loss of response by a large percentage of patients taking anti-tumor necrosis factor-alpha agents. Drug monitoring can be extremely useful, allowing physicians to adjust the therapeutic scheme individually. This article aims to systematically review the published data with respect to cutoff levels of infliximab (IFX) and adalimumab (ADA) and relate them to the methodology adopted for quantification of IFX and ADA levels and clinical outcomes.

METHODS

The PubMed database was searched to identify studies focusing on the association between IFX or ADA cutoff levels and clinical outcomes in patients with inflammatory bowel disease.

RESULTS

Of the 1654 articles initially selected by queries, 20 were included. A receiver operating characteristic curve analysis was performed to identify cutoff levels of IFX or ADA that correlated with a clinical outcome, but only 6 studies performed the same analysis for antidrug antibody levels. Cutoff levels were different between studies. The methodology chosen for level quantifications, clinical outcomes, and sample size and characteristics were also different. Nevertheless, measurement of drug levels should be performed during maintenance, and with loss of response, with persistent high levels of C-reactive protein, and when mucosal lesions are still present. In these scenarios, drug and antidrug levels were correlated with clinical outcomes.

CONCLUSIONS

Concerning drug levels monitoring any methodology is adequate. With respect to antidrug antibody levels, it will be necessary to define a gold standard method or to establish different cutoff levels for different methodologies.

The Role of Laboratory Tests in Crohn's Disease

In the past, laboratory tests were considered of limited value in Crohn's disease (CD). In the era of biologics, laboratory tests have become essential to evaluate the inflammatory burden of the disease (C-reactive protein, fecal calprotectin) since symptoms-based scores are subjective, to predict the response to pharmacological options and the risk of relapse, to discriminate CD from ulcerative colitis, to select candidates to anti-tumor necrosis factors [screening tests looking for hepatitis B virus and hepatitis C virus status and latent tuberculosis], to assess the risk of adverse events (testing for thiopurine metabolites and thiopurine-methyltransferase activity), and to personalize and optimize therapy (therapeutic drug monitoring). Pharmacogenetics, though presently confined to the assessment of thiopurineme methyltransferase polymorphisms and hematological toxicity associated with thiopurine treatment, is a promising field that will contribute to a better understanding of the molecular mechanisms of the variability in response to the drugs used in CD with the attempt to expand personalized care and precision medicine strategies.

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.

Clinical efficacy of adalimumab in Crohn's disease: a real practice observational study in Japan

Background

There are few reports of the efficacy of adalimumab (ADA) for clinical remission and preventing postoperative recurrence in Crohn's disease (CD) in Asian real practice settings. We conducted a Japanese multicenter retrospective observational study.

Methods

We evaluated patients with CD who were treated with ADA at 11 medical institutions in Japan to investigate the clinical efficacy of remission up to 52 weeks and the associated factors to achieve remission with a CD Activity Index (CDAI) < 150. The effects of preventing postoperative recurrence were also evaluated.

Results

In 62 patients, the remission rates were 33.9, 74.2, 75.8, 77.4, and 66.1 % at 0, 4, 12, 26, and 52 weeks, respectively. Although 10 patients discontinued treatment due to primary nonresponse, secondary nonresponse, or adverse events, the ongoing treatment rate at 52 weeks was 83.9 %. Comparison of remission and non-remission on univariate analysis identified colonic type and baseline CDAI value as significant associated factors (P < 0.05). In 16 patients who received ADA to prevent postoperative recurrence, the clinical remission maintenance rate was 93.8 % and the mucosal healing rate was 64.3 % during a mean postoperative follow-up period of 32.3 months.

Conclusions

ADA effectively induced remission and prevented postoperative recurrence in patients with CD in a real practice setting.

Time Course and Clinical Implications of Development of Antibodies Against Adalimumab in Patients With Inflammatory Bowel Disease

BACKGROUND

Antibodies (Abs) against adalimumab (ADL) have been associated with low ADL levels and treatment failure.

AIM

To characterize the temporal characteristics of anti-ADL Ab appearance and possible disappearance, and determine the clinical significance on drug efficacy and disease course.

METHODS

Cohort study including inflammatory bowel disease patients in whom anti-ADL Abs had been assessed by radioimmunoassay (RIA) and, in case of disappearance, by enzyme immunoassay, and functional reporter gene assay.

RESULTS

Anti-ADL Abs were evaluated in 133 serum samples from 72 patients. Seventeen patients (24%) tested positive after median of 194 days, interquartile range of 66 to 361. The proportion with anti-ADL Abs was 22% after 1 year, and 32% from 21 months onwards. Anti-ADL Abs generally persisted at repeat assessments during continued ADL therapy (n=8). Disappearance of anti-ADL Abs during therapy (n=3) was presumably caused by methodological biases due to detection of nonfunctional nonpersistent anti-ADL Abs by RIA, or false-negative measurement at reassessment by RIA and reporter gene assay. Anti-ADL Abs appeared pharmacologically active as judged by a median ADL concentration below limit of detection versus 7.4 μg/mL in anti-ADL Ab-negative samples (P<0.0001). Anti-ADL Abs associated with loss of response (odds ratio estimated 67, P<0.0001), and shorter treatment duration (P<0.0001).

CONCLUSIONS

Abs against ADL appear in approximately one fourth of inflammatory bowel disease patients with decreasing frequency over time and usually within 1 year of therapy. Anti-ADL Abs generally persist during continued ADL therapy, and are associated with elimination of drug and treatment failure. Therefore, ADL cessation should be considered when anti-ADL Abs are detected and supported by clinical observations.

Predicting durable response or resistance to antitumor necrosis factor therapy in inflammatory bowel disease

Monoclonal antibodies to tumor necrosis factor (TNF) have become a mainstay of the therapeutic armamentarium in inflammatory bowel disease (IBD) over the last 15 years. Although highly effective, primary and secondary nonresponse are common and associated with poor clinical outcomes and significant costs. Multiple clinical, genetic and immunopharmacological factors may impact the response to anti-TNFs. Early stratification of IBD patients by the expected risk of therapeutic failure during the induction and maintenance phases of treatment may allow for treatment optimization and potentially optimal short- and long-term outcomes. The aim of this review is to summarize the current data concerning the potential predictors of therapeutic success and failure of anti-TNFs in IBD.

How Will Evolving Future Therapies and Strategies Change How We Position the Use of Biologics in Moderate to Severely Active Inflammatory Bowel Disease

Several biological agents have been added to our armamentarium of treatment options for moderate to severely active inflammatory bowel diseases, and this number is expected to only increase in the near future. With our growing understanding of disease mechanisms and pharmacokinetics, we are now able to target several mechanisms of action to achieve key endpoints (steroid-free remission and mucosal healing) associated with improved long-term disease-related outcomes. In this context, concerns arise regarding the optimal positioning of currently available biologics and key biologics in development. In this review, we will discuss the currently available evidence for comparative effectiveness of biological agents approved for the use in moderate to severely active inflammatory bowel diseases, with a focus on practical considerations to be made when using these agents in practice. We will further review novel biological agents and small molecule inhibitors in development and discuss future opportunities through which providers may personalize treatment decisions to achieve optimal treatment outcomes.

Infliximab Concentration Thresholds During Induction Therapy Are Associated With Short-term Mucosal Healing in Patients With Ulcerative Colitis

BACKGROUND & AIMS

Mucosal healing is an independent predictor of sustained clinical remission in patients with ulcerative colitis (UC) treated with infliximab. We investigated whether infliximab concentrations during induction therapy are associated with short-term mucosal healing (STMH) in patients with UC.

METHODS

We performed a retrospective, single-center analysis of data collected from a tertiary referral center from 101 patients with UC who received scheduled induction therapy with infliximab at weeks 0, 2, and 6 and had an endoscopic evaluation at baseline and after induction therapy. STMH was defined as Mayo endoscopic sub-score ≤1, assessed at weeks 10-14, with baseline sub-score ≥2. Infliximab concentrations were evaluated in serum samples collected at weeks 0, 2, 6, and 14 of infliximab therapy by using an enzyme-linked immunosorbent assay we developed.

RESULTS

Fifty-four patients (53.4%) achieved STMH. Patients with STMH had a higher median infliximab concentration at weeks 2, 6, and 14 than patients without STMH. A receiver operating characteristic (ROC) analysis identified infliximab concentration thresholds of 28.3 (area under the ROC curve [AUROC], 0.638), 15 (AUROC, 0.688), and 2.1 μg/mL (AUROC, 0.781) that associated with STMH at weeks 2, 6, and 14, respectively. Multiple logistic regression analysis identified infliximab concentration ≥15 at week 6 (P = .025; odds ratio, 4.6; 95% confidence interval, 1.2-17.1) and ≥2.1 μg/mL at week 14 (P = .004; odds ratio, 5.6; 95% confidence interval, 1.7-18) as independent factors associated with STMH.

CONCLUSIONS

In an analysis of data from real-life clinical practice, we associated infliximab concentrations during the induction therapy with STMH in patients with UC.

Optimizing Anti-TNF-α Therapy: Serum Levels of Infliximab and Adalimumab Are Associated With Mucosal Healing in Patients With Inflammatory Bowel Diseases

BACKGROUND & AIMS

It is not clear what serum levels of anti-tumor necrosis factor are associated with reduced intestinal inflammation in patients with inflammatory bowel disease (IBD). We aimed to identify serum levels of infliximab and adalimumab associated with mucosal healing in patients with IBD and to evaluate the putative gain in control of inflammation by incremental increases in drug levels.

METHODS

We performed a retrospective cross-sectional study of 145 patients with IBD treated with infliximab (n = 78) or adalimumab (n = 67) at a medical center in Israel from 2009 through 2014. We collected data from colonoscopy examinations; mucosal healing was defined as simple endoscopic score of <3 or a Mayo score ≤1. These data were compared with serum levels of anti-tumor necrosis factor agents, clinical scores, and levels of C-reactive protein.

RESULTS

Median serum levels of infliximab and adalimumab were significantly higher in patients with mucosal healing than patients with active disease (based on endoscopy) (for infliximab, 4.3 vs 1.7 μg/mL, P = .0002; for adalimumab, 6.2 vs 3.1 μg/mL, P = .01). Levels of infliximab above 5 μg/mL (area under the curve = 0.75; P < .0001) and levels of adalimumab above 7.1 μg/mL (area under the curve = 0.7; P = .004) identified patients with mucosal healing with 85% specificity. Increasing levels of infliximab beyond 8 μg/mL produced only minimal increases in the rate of mucosal healing, whereas the association between higher level of adalimumab and increased rate of mucosal healing reached a plateau at 12 μg/mL. In patients with measurable levels of infliximab >3 μg/mL, the presence of antibodies to infliximab was associated with a lower rate of mucosal healing compared with patients with similar drug level without antibodies (16% vs 50%, respectively; P = .003).

CONCLUSIONS

In a retrospective study, we found significant association between serum levels of anti-tumor necrosis factor agents and level of mucosal healing. We propose that serum levels of 6-10 μg/mL for infliximab and 8-12 μg/mL for adalimumab are required to achieve mucosal healing in 80%-90% of patients with IBD, and that this could be considered as a "therapeutic window." Exceeding these levels produces only a negligible gain in proportion of patients with mucosal healing.

Generation and characterization of a unique panel of anti-adalimumab specific antibodies and their application in therapeutic drug monitoring assays

A number of assays are currently available to support therapeutic drug monitoring of adalimumab. A complete characterization of the assays and comparison of different assays has not been performed. The aim of this study, therefore, is to generate and characterize of a panel of monoclonal antibodies towards adalimumab (MA-ADM); to use this panel to develop novel assays to determine adalimumab concentrations; to assess the impact of tumor necrosis factor (TNF) and (non-)neutralizing antibodies on adalimumab detection and to compare the performance of assays. In total, ten specific MA-ADM were generated of which four revealed a neutralizing potency of >78%. At least six different clusters were identified using principal component analysis. MA-ADM40D8 was selected as detecting antibody to determine adalimumab in the TNF-coated ELISA (A) and the MA-ADM28B8/MA-ADM40D8 antibody pair was chosen for use in the MA-coated ELISA (B). The impact of TNF and (non-) neutralizing antibodies was similar in both ELISAs. Finally, serum samples of adalimumab-treated Crohn's disease patients were collected and used for an external validation using the assay of Sanquin (C) and the apDia kit (D). All adalimumab assays showed excellent Pearson correlation: r=0.96 for A versus B, 0.96 for A versus C, 0.94 for A versus D, 0.97 for B versus C, 0.95 for B versus D and 0.94 for C and D. The excellent agreement with the two commercially available ELISAs allows harmonization of treatment algorithms in and between different hospitals/infusion centers.

Adalimumab and pharmacokinetics: Impact on the clinical prescription for inflammatory bowel disease

Anti-tumor necrosis factor (TNF) drugs are widely prescribed for inflammatory disease. A loss of response to adalimumab is frequent and the pharmacokinetics of anti-TNF therapy have important implications for patient management. Individual factors such as albumin, body weight, and disease severity based on the C-reactive protein level influence drug metabolism. Adalimumab trough levels are associated with clinical remission. On the other hand, the detection of antibodies is associated with clinical relapse. Immunosuppressive therapy could reduce antibody formation although the clinical impact is not proven. New algorithms are available to provide personalized treatment and adapt the dosage. More data are needed on dose de-escalation.

Treat to Target in Inflammatory Bowel Disease

OPINION STATEMENT

With the expanding armamentarium in IBD the current treatment targets can be reached. By optimally using our drugs we can avoid long-term complications in IBD. For this the therapeutic strategy has to be changed from a clinically driven approach to a target-driven strategy. Currently mucosal healing, normalization of biomarkers, histological healing, and healing on abdominal imaging are proposed targets. Correct phenotyping of the patient before initiation of therapy is mandatory. Once treatment is initiated a continuous re-evaluation with consequent adaptation of the treatment when goals are not (yet) reached is needed. Both escalation and de-escalation should be considered. Drug levels can be used as a guidance to reach these targets.

Emerging issues in the medical management of Crohn's disease

PURPOSE OF REVIEW

This article describes why this review is timely and relevant. The medical management of Crohn's disease is complex, and is changing rapidly with the introduction of novel therapeutic agents and management strategies.

RECENT FINDINGS

We have summarized and synthesized up-to-date evidence and opinion on the proper role and composition of combined immunosuppressive therapy in the management of Crohn's disease, the optimal time for introduction of immunomodulator and/or biologic therapies, and the benefits of therapeutic drug monitoring for biologic therapies. We also discuss the evidence supporting the benefits of the novel agents vedolizumab and ustekinumab, and discuss where they will fit into the therapeutic landscape.

SUMMARY

The review will provide evidence to support decision making in patients with Crohn's disease requiring biologic and/or immunomodulator therapy.

Higher Adalimumab Levels Are Associated with Histologic and Endoscopic Remission in Patients with Crohn's Disease and Ulcerative Colitis

BACKGROUND

Optimal levels of adalimumab (ADA) have not been defined according to the ultimate goal of inflammatory bowel disease treatment--histologic and/or endoscopic healing. The aim of this study was to assess the relationship between random serum ADA levels and histologic and endoscopic healing in patients with inflammatory bowel disease.

METHODS

This was a cross-sectional study including 66 patients receiving maintenance therapy with ADA for Crohn's disease or ulcerative colitis. ADA levels and anti-adalimumab antibodies (AAA) were measured at the time of colonoscopy. The primary outcome was histologic healing (lack of endoscopic and histologic inflammation) and the secondary outcomes were endoscopic healing and serum levels of C-reactive protein, tumor necrosis factor, ICAM, VCAM, and interleukins 1β, 6, and 8.

RESULTS

Sixty-six patients (59 with Crohn's disease) were included. Mean random ADA levels were significantly lower in patients with histologic and endoscopic inflammation (9.2 [SD: 8.4] versus 14.1 [6.4] μg/mL, P = 0.03 and 8.5 [SD: 7.8] versus 13.3 [SD: 7.7], P = 0.02, respectively). The ADA level that was best associated with histologic healing was 7.8 μg/mL (receiver operating characteristic: 0.76 [P = 0.04]), whereas the ADA level that was best associated with endoscopic healing was 7.5 μg/mL (receiver operating characteristic: 0.73 [P = 0.02]). The presence of AAA was associated with lower random ADA levels (5.7 versus 12.5 μg/mL, P = 0.002) and higher C-reactive protein levels (30.3 versus 12.0, P = 0.01).

CONCLUSIONS

Achievement of histologic and endoscopic healing may require higher levels of ADA than previously described for endoscopic remission. The measurement of random ADA levels and anti-drug antibodies may guide therapy and edify the course of incomplete responses.

Loss of Response to Anti-TNFs: Definition, Epidemiology, and Management

Tumor necrosis factor-α (TNFα) antagonists have advanced the management of inflammatory bowel diseases patients leading to an improvement of patient's quality of life with the reduction of number of surgeries and hospitalizations. Despite these advances, many patients do not respond to the induction therapy (primary non-response-PNR) or lose response during the treatment (secondary loss of response-LOR). In this paper we will provide an overview of the definition, epidemiology and risk factors for PNR and LOR, as well as discuss the therapeutic options for managing LOR.

Systematic review: predicting and optimising response to anti-TNF therapy in Crohn's disease - algorithm for practical management

BACKGROUND

Nonresponse and loss of response to anti-TNF therapies in Crohn's disease represent significant clinical problems for which clear management guidelines are lacking.

AIM

To review the incidence, mechanisms and predictors of primary nonresponse and secondary loss of response to formulate practical clinical algorithms to guide management.

METHODS

Through a systematic literature review, 503 articles were identified which fit the inclusion criteria.

RESULTS

Primary nonresponse to anti-TNF treatment affects 13-40% of patients. Secondary loss of response to anti-TNF occurs in 23-46% of patients when determined according to dose intensification, and 5-13% of patients when gauged by drug discontinuation rates. Recent evidence suggests that the mechanisms underlying primary nonresponse and secondary loss of response are multifactorial and include disease characteristics (phenotype, location, severity); drug (pharmacokinetic, pharmacodynamic or immunogenicity) and treatment strategy (dosing regimen) related factors. Clinical algorithms that employ therapeutic drug monitoring (using anti-TNF tough levels and anti-drug antibody levels) may be used to determine the underlying cause of primary nonresponse and secondary loss of response respectively and guide clinicians as to which patients are most likely to respond to anti-TNF therapy and help optimise drug therapy for those who are losing response to anti-TNF therapy.

CONCLUSIONS

Nonresponse or loss of response to anti-TNF occurs commonly in Crohn's disease. Clinical algorithms utilising therapeutic drug monitoring may establish the mechanisms for treatment failure and help guide the subsequent therapeutic approach.

How should immunomodulators be optimized when used as combination therapy with anti-tumor necrosis factor agents in the management of inflammatory bowel disease?

In the last 15 years the management of inflammatory bowel disease has evolved greatly, largely through the increased use of immunomodulators and, especially, anti-tumor necrosis factor (anti-TNF) biologic agents. Within this time period, confidence in the use of anti-TNFs has increased, whilst, especially in recent years, the efficacy and safety of thiopurines has been questioned. Yet despite recent concerns regarding the risk: benefit profile of thiopurines, combination therapy with an immunomodulator and an anti-TNF has emerged as the recommended treatment strategy for the majority of patients with moderate-severe disease, especially those who are recently diagnosed. Concurrently, therapeutic drug monitoring has emerged as a means of optimizing the dosage of both immunomodulators and anti-TNFs. However the recommended therapeutic target levels for both drug classes were largely derived from studies of monotherapy with either agent, or studies underpowered to analyze outcomes in combination therapy patients. It has been assumed that these target levels are applicable to patients on combination therapy also, however there are few data to support this. Similarly, the timing and duration of treatment with immunomodulators when used in combination therapy remains unknown. Recent attention, including post hoc analyses of the pivotal registration trials, has focused on the optimization of anti-TNF agents, when used as either monotherapy or combination therapy. This review will instead focus on how best to optimize immunomodulators when used in combination therapy, including an evaluation of recent data addressing unanswered questions regarding the optimal timing, dosage and duration of immunomodulator therapy in combination therapy patients.

Current stage in inflammatory bowel disease: What is next?

In recent years, the incidence of inflammatory bowel disease (IBD) has been on the rise, extending to countries where it was infrequent in the past. As a result, the gap between high and low incidence countries is decreasing. The disease, therefore, has an important economic impact on the healthcare system. Advances in recent years in pharmacogenetics and clinical pharmacology have allowed for the development of treatment strategies adjusted to the patient profile. Concurrently, new drugs aimed at inflammatory targets have been developed that may expand future treatment options. This review examines advances in the optimization of existing drug treatments and the development of novel treatment options for IBD.

[Anti-TNF biosimilars in chronic inflammatory bowel disease. What can rheumatologists learn from it?]

BACKGROUND

The expiry of the patent for tumor necrosis factor (TNF)-binding antibodies allowed the approval of biosimilars.

OBJECTIVES

Assessment and discussion of specific aspects of anti-TNF biosimilars in the therapy of inflammatory bowel diseases.

METHODS

Review and discussion of currently available literature.

RESULTS

The use of TNF-binding antibodies differs between the therapy of rheumatoid disorders and inflammatory bowel diseases. Clinical proof of efficacy for biosimilars for infliximab has been achieved in rheumatoid diseases because activity indices are more stable than in inflammatory bowel diseases and require extrapolation. The TNF-binding antibodies, in particular infliximab, adalimumab and golimumab play a central role in the first-line therapy of inflammatory bowel diseases.

CONCLUSION

The use of TNF-binding biosimilars for patients suffering from inflammatory bowel diseases is possible through extrapolation. Competition should not only drive a price reduction but also a better clinical profiling of anti-TNF therapy for patients with inflammatory bowel diseases. Missing information for "best use" include optimal strategies for dosing and timing for introduction during the course of Crohn's disease and ulcerative colitis.