Antibodies to adalimumab are associated with future inflammation in Crohn's patients receiving maintenance adalimumab therapy: a post hoc analysis of the Karmiris trial

HLA DQA1*05 and Risk of Antitumor Necrosis Factor Treatment Failure and Anti-Drug Antibody Development in Children With Crohn's Disease

INTRODUCTION

Human leukocyte antigen (HLA) DQA1*05 has been associated with the development of anti-drug antibodies (ADA) to tumor necrosis factor antagonists (anti-TNFα) and treatment failure among adults with Crohn's disease (CD). However, findings from other studies have been inconsistent with limited pediatric data.

METHODS

We analyzed banked serum from patients with CD aged <21 years enrolled in clinical outcomes of Methotrexate Binary Therapy in practice, a multicenter, prospective randomized trial of anti-TNFα monotherapy vs combination with methotrexate. The primary outcome was a composite of factors indicative of treatment failure. The secondary outcome was ADA development.

RESULTS

A trend toward increased treatment failure among HLA DQA1*05-positive participants was not significant (hazard ratio 1.58, 95% confidence interval [CI] 0.95-2.62; P = 0.08). After stratification by HLA DQA1*05 and by methotrexate vs placebo, patients who were HLA DQA1*05 negative and assigned to methotrexate experienced less treatment failures than HLA DQA1*05-positive patients on placebo (hazard ratio 0.31, 95% CI 0.13-0.70; P = 0.005). A trend toward increased ADA development among HLA DQA1*05-positive participants was not significant (odds ratio 1.96, 95% CI 0.90-4.31, P = 0.09). After further stratification, HLA DQA1*05-negative participants assigned to methotrexate were less likely to develop ADA relative to HLA DQA1*05-positive patients on placebo (odds ratio 0.12, 95% CI 0.03-0.55; P = 0.008).

DISCUSSION

In a randomized trial of children with CD initiating anti-TNFα, 40% were HLA DQ-A1*05 positive, which was associated with a trend toward increased risk of both treatment failure and ADA. These risks were mitigated, but not eliminated, by adding oral methotrexate. HLA DQ-A1*05 is an important biomarker for prognosis and risk stratification.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

A prediction method for the individual serum concentration and therapeutic effect for optimizing adalimumab therapy in inflammatory bowel disease

OBJECTIVES

Adalimumab (ADM) therapy is effective for inflammatory bowel disease (IBD), but a significant number of IBD patients lose response to ADM. Thus, it is crucial to devise methods to enhance ADM's effectiveness. This study introduces a strategy to predict individual serum concentrations and therapeutic effects to optimize ADM therapy for IBD during the induction phase.

METHODS

We predicted the individual serum concentration and therapeutic effect of ADM during the induction phase based on pharmacokinetic and pharmacodynamic (PK/PD) parameters calculated using the empirical Bayesian method. We then examined whether the predicted therapeutic effect, defined as clinical remission or treatment failure, matched the observed effect.

RESULTS

Data were obtained from 11 IBD patients. The therapeutic effect during maintenance therapy was successfully predicted at 40 of 47 time points. Moreover, the predicted effects at each patient's final time point matched the observed effects in 9 of the 11 patients.

CONCLUSION

This is the inaugural report predicting the individual serum concentration and therapeutic effect of ADM using the Bayesian method and PK/PD modelling during the induction phase. This strategy may aid in optimizing ADM therapy for IBD.

Immunogenicity of Therapeutic Antibodies Used for Inflammatory Bowel Disease: Treatment and Clinical Considerations

The introduction of tumor necrosis factor inhibitors has led to a paradigm shift in the management of inflammatory bowel disease (IBD). The subsequent introduction of both anti-integrins and cytokine blockers has since expanded the biologic armamentarium. However, immunogenicity, defined as the production of anti-drug antibodies (ADAs) to the prescribed biopharmaceutical, means a significant fraction of patients exposed to biologic agents will experience a secondary loss of response to one or more of the drugs. In clinical settings, immunogenicity may be caused by several factors, both patient related (e.g., underlying chronic disease, systemic immune burden, including previous biologic therapy failure, and [epi]genetic background) and treatment related (e.g., dose and administration regimens, drug physical structure, photostability, temperature, and agitation). Here, we outline these elements in detail to enhance biopharmaceutical delivery and therapy for patients with IBD. Moreover, concurrent immunomodulator medication may reduce the risks of ADA generation, especially when using the chimeric drug infliximab. Summarizing the latest developments and knowledge in the field, this review aims to provide strategies to prevent ADA production and information on managing non-responsiveness or loss of response to biologics. Better understanding of the molecular mechanisms underlying the formation of ADAs and the critical factors influencing the immunogenicity of biopharmaceuticals may lead to improved health outcomes in the IBD community that may benefit both the individual patient and society through lower healthcare expenses.

Dynamics and implications of anti-drug antibodies against adalimumab using ultra-sensitive and highly drug-tolerant assays

Background

Adalimumab induces the production of anti-drug antibodies (ADA) that may lead to reduced drug concentration and loss-of-response, posing significant clinical challenges. However, traditional immunoassays have limitations in terms of sensitivity and drug-tolerance, hindering the insights of ADA response.

Methods

Herein, we developed an integrated immunoassay platform combining the electrochemiluminescence immunoassay with immunomagnetic separation strategy. A longitudinal cohort study involving 49 patients with ankylosing spondylitis was carried out to analyze the dynamic profiles of ADA and to investigate the impact of ADA on adalimumab pharmacokinetics using a population pharmacokinetic model. Additionally, cross-sectional data from 12 patients were collected to validate the correlation between ADA levels and disease relapse.

Results

The ADA assay demonstrated high sensitivity (0.4 ng/mL) and drug-tolerance (100 μg/mL), while the neutralizing antibodies (NAB) assay showed a sensitivity of 100 ng/mL and drug-tolerance of 20 μg/mL. Analysis of the longitudinal cohort revealed that a majority of patients (44/49, 90%) developed persistent ADA within the first 24 weeks of treatment. ADA levels tended to plateau over time after an initial increase during the early immune response phase. Further, nearly all of the tested patients (26/27, 96%) were classified as NAB positive, with a strong correlation between ADA levels and neutralization capacity (R2 = 0.83, P < 0.001). Population pharmacokinetic modeling revealed a significant positive association between model-estimated individual clearance and observed ADA levels. Higher ADA levels were associated with adalimumab clearance and disease relapse in a cross-sectional cohort, suggesting a promising ADA threshold of 10 for potential clinical application. Moreover, the IgG class was the primary contributor to ADA against adalimumab and the apparent affinity exhibited an increasing trend over time, indicating a T-cell dependent mechanism for ADA elicitation by adalimumab.

Conclusion

In summary, this integrated immunoassay platform shows promise for in-depth analysis of ADA against biologics, offering fresh insights into immunogenicity and its clinical implications.

What are the benefits of therapeutic drug monitoring in the optimization of adalimumab therapy? a systematic review and meta-analysis up to 2022

Aims

Persistent uncertainties exist surrounding the therapeutic drug monitoring (TDM) of adalimumab in clinical settings. To address these issues, we conducted a systematic review to assess the current evidence regarding the benefits of TDM for adalimumab.

Methods

PubMed, EMBASE, and Cochrane Databases were searched from inception to October 2022. The trials regarding to the list three key questions were considered: 1) Could routine proactive TDM assist in improving outcomes in patients receiving adalimumab? 2) Could reactive TDM assist in guiding subsequent treatment strategies for patients with treatment failure to adalimumab? 3) Could TDM assist in informing dose reduction or discontinuation in patients with low disease activity or in remission treated with adalimumab? Two reviewers independently selected the studies and extracted the data. Meta-analysis was performed to calculate the relative risk (RR) and 95% confidence interval (CI).

Results

A total of 9 studies was included in this review. For proactive TDM, meta-analysis indicated that proactive TDM (n = 163/257, 63.42%) showed no significant superiority over reactive TDM and/or conventional management (n = 336/606, 55.44%) in achieving and/or maintaining clinical remission by random effects model (RR: 1.24, 95% CI 0.98-1.58, I 2 = 73%). There were three studies that supporting the reactive TDM, low drug levels in the absence of anti-drug antibodies (ADA) strongly indicate the need for dose intensification, and infliximab is a feasible choice for patients with low drug levels and ADA positivity. While swapping to another class should be considered in patients with adequate drug levels. In addition, TDM can help clinicians optimize dosing schedules and prevent overtreatment in patients who have achieved low disease activity and sufficient drug concentrations, with no predictive value for successful adalimumab discontinuation.

Conclusion

Current evidence suggests that proactive TDM is numerically but not statistically significant superiority over reactive TDM and/or conventional management. Reactive TDM can aid in understanding treatment failure and developing subsequent therapy. For patients reaching low disease activity and remission, TDM can help successful dose reduction, while it cannot inform the successful drug discontinuation. However, existing trials are limited, and more well-designed trials are necessary to clarify the role of TDM in adalimumab treatment.

Therapeutic Antibodies in Medicine

Antibody engineering has developed into a wide-reaching field, impacting a multitude of industries, most notably healthcare and diagnostics. The seminal work on developing the first monoclonal antibody four decades ago has witnessed exponential growth in the last 10-15 years, where regulators have approved monoclonal antibodies as therapeutics and for several diagnostic applications, including the remarkable attention it garnered during the pandemic. In recent years, antibodies have become the fastest-growing class of biological drugs approved for the treatment of a wide range of diseases, from cancer to autoimmune conditions. This review discusses the field of therapeutic antibodies as it stands today. It summarizes and outlines the clinical relevance and application of therapeutic antibodies in treating a landscape of diseases in different disciplines of medicine. It discusses the nomenclature, various approaches to antibody therapies, and the evolution of antibody therapeutics. It also discusses the risk profile and adverse immune reactions associated with the antibodies and sheds light on future applications and perspectives in antibody drug discovery.

Early At-Home Measurement of Adalimumab Concentrations to Guide Anti-TNF Precision Dosing: A Pilot Study

BACKGROUND AND OBJECTIVE

Underdosing of adalimumab can result in non-response and poor disease control in patients with rheumatic disease or inflammatory bowel disease. In this pilot study we aimed to predict adalimumab concentrations with population pharmacokinetic model-based Bayesian forecasting early in therapy.

METHODS

Adalimumab pharmacokinetic models were identified with a literature search. A fit-for-purpose evaluation of the model was performed for rheumatologic and inflammatory bowel disease (IBD) patients with adalimumab peak (first dose) and trough samples (first and seventh dose) obtained by a volumetric absorptive microsampling technique. Steady state adalimumab concentrations were predicted after the first adalimumab administration. Predictive performance was calculated with mean prediction error (MPE) and normalised root mean square error (RMSE).

RESULTS

Thirty-six patients (22 rheumatologic and 14 IBD) were analysed in our study. After stratification for absence of anti-adalimumab antibodies, the calculated MPE was -2.6% and normalised RMSE 24.0%. Concordance between predicted and measured adalimumab serum concentrations falling within or outside the therapeutic window was 75%. Three patients (8.3%) developed detectable concentrations of anti-adalimumab antibodies.

CONCLUSION

This prospective study demonstrates that adalimumab concentrations at steady state can be predicted from early samples during the induction phase.

CLINICAL TRIAL REGISTRATION

The trial was registered in the Netherlands Trial Register with trial registry number NTR 7692 ( www.trialregister.nl ).

A Systematic Review on the Interest of Drug-tolerant Assay in the Monitoring of Inflammatory Bowel Disease

Many patients with inflammatory bowel disease [IBD] are treated with anti-tumour necrosis factor [TNF] therapies, of which infliximab [IFX] is most commonly used. Loss of response [LOR] to anti-TNF therapy due to immunogenic failure accounts for 20% of subsequent medical intervention and is defined, using a drug-sensitive assay, as low or undetectable concentration of drug with high titres of anti-drug antibodies [ADAb]. We performed a systematic review to investigate the use of a drug-tolerant assay during both induction and maintenance, to monitor patients treated with anti-TNFs. After the search on PubMed, 90 publications were reviewed. Most ADAb detection methods are drug-sensitive, cannot detect ADAb in the presence of drug, and therefore cannot be used close to drug administration when the drug concentration is too high. To overcome this major limitation, several drug-tolerant techniques have been developed and will be discussed in this review. Using drug-tolerant assays, ADAb against IFX or adalimumab [ADM] can be detected during induction and predict primary non-response or LOR. Drug-sensitive assays do not allow detection of ADAb during the induction phase when IFX or ADM concentration is typically high.

Recent Advances in the Optimization of Anti-TNF Treatment in Patients with Inflammatory Bowel Disease

Despite the evolution in inflammatory bowel disease (IBD) management during the last 20 years owing to the advent of new advanced therapies, anti-TNF agents still remain the cornerstone of therapy for both Crohn's disease and ulcerative colitis. However, this does not only secure favorable outcomes for patients considering the progressive disease character and the high likelihood of primary or secondary loss of response. Therefore, trying to reach a better treatment approach and maximize the benefits anti-TNF agents offer, optimization strategies should be examined. It has been indicated that optimizing treatment with anti-TNF enhances drug efficacy and has been associated with improved disease outcomes and a complication-free disease course. From this perspective, we aim to provide an overview of currently available data and recent advances in the practices of anti-TNF treatment optimization. Special focus has been given to the role of therapeutic drug monitoring (TDM), as well as the utility of combining anti-TNF with an immunomodulator and the treat-to-target approach.

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.

Relationship between clinical remission of perianal fistulas in Crohn’s disease and serum adalimumab concentrations: A multi-center cross-sectional study

BACKGROUND

Crohn’s disease (CD) is complicated by perianal fistulas in approximately 20% of patients. Achieving permanent fistula closure remains a challenge for physicians. An association between serum anti-tumor necrosis factor-α concentrations and clinical outcomes in patients with CD has been demonstrated; however, little information is available on serum adalimumab (ADA) concentrations and remission of perianal fistulas in such patients.

AIM

To study the relationship between serum ADA concentrations and clinical remission of CD-associated perianal fistulas.

METHODS

This cross-sectional study of patients with CD-associated perianal fistulas treated with ADA was performed at four French hospitals between December 2013 and March 2018. At the time of each serum ADA concentration measurement, we collected information about the patients and their fistulas. The primary study endpoint was clinical remission of fistulas defined as the absence of drainage (in accordance with Present’s criteria), with a PDAI ≤ 4, absence of a seton and assessment of the overall evaluation as favorable by the proctologist at the relevant center. We also assessed fistula healing [defined as being in clinical and radiological (magnetic resonance imaging, MRI) remission] and adverse events.

RESULTS

The study cohort comprised 34 patients who underwent 56 evaluations (patients had between one and four evaluations). Fifteen patients had clinical remissions (44%), four of whom had healed fistulas on MRI. Serum ADA concentrations were significantly higher at evaluations in which clinical remission was identified than at evaluations in which it was not [14 (10-16) vs 10 (2-15) μg/mL, P = 0.01]. Serum ADA concentrations were comparable at the times of evaluation of patients with and without healed fistulas [11 (7-14) vs 10 (4-16) μg/mL, P = 0.69]. The adverse event rate did not differ between different serum ADA concentrations.

CONCLUSION

We found a significant association between high serum ADA concentrations and clinical remission of CD-associated perianal fistulas.

Therapeutic Drug Monitoring of Biologics for Patients with Inflammatory Bowel Diseases: How, When, and for Whom?

During the past decade, we have entered an era of biologics for the treatment of Crohn’s disease and ulcerative colitis. The therapeutic goal of inflammatory bowel disease (IBD) management has evolved from symptom control and clinical remission to mucosal healing or even deep remission. Histological remission for ulcerative colitis and transmural healing of Crohn’s disease are potential future goals. With the adoption of the treat-to-target concept, and given the need for tight control of IBD activity, therapeutic drug monitoring (TDM) is an important element of precision medicine. TDM involves the measurement of serum biologics and anti-drug antibodies levels, to confirm whether the right drug with the right dosage was prescribed to reach the right serum levels. TDM may help clinicians adjust biologics based on objective biomarkers instead of using empirical dosage escalation or making symptom-based therapeutic adjustments. Well-established reactive TDM algorithms have been proposed, and emerging evidence supports the clinical application of a proactive TDM strategy to enhance the duration of effective biologics and improve clinical outcomes. Recently, the proactive TDM strategy was shown to avoid the secondary loss of response to biologics, and improve long-term clinical outcomes in IBD patients. This review summarizes data from trials, and practice guidelines, on the clinical application of proactive and reactive TDM strategies for the daily care of biologic-treated IBD patients.

A Comprehensive Literature Review and Expert Consensus Statement on Therapeutic Drug Monitoring of Biologics in Inflammatory Bowel Disease

Therapeutic drug monitoring (TDM) of biologics is a rapidly evolving field. We aimed to provide a consensus statement regarding the clinical utility of TDM for biologics in inflammatory bowel disease (IBD). A modified Delphi method was applied to develop consensus statements. A comprehensive literature review was performed regarding TDM of biologic therapies in IBD, and 45 statements were subsequently formulated on the potential application of TDM in IBD. The statements, along with literature, were then presented to a panel of 10 gastroenterologists with expertise in IBD and TDM who anonymously rated them on a scale of 1-10 (1 = strongly disagree and 10 = strongly agree). An expert consensus development meeting was held virtually to review, discuss, refine, and reformulate statements that did not meet criteria for agreement or that were ambiguous. During the meeting, additional statements were proposed. Panelists then confidentially revoted, and statements rated ≥7 by 80% or more of the participants were accepted. During the virtual meeting, 8 statements were reworded, 7 new statements were proposed, and 19 statements were rerated. Consensus was finally reached in 48/49 statements. The panel agreed that reactive TDM should be used for all biologics for both primary nonresponse and secondary loss of response. It was recommended that treatment discontinuation should not be considered for infliximab or adalimumab until a drug concentration of at least 10-15 μg/mL was achieved. Consensus was also achieved regarding the utility of proactive TDM for anti-tumor necrosis factor therapy. It was recommended to perform proactive TDM after induction and at least once during maintenance. Consensus was achieved in most cases regarding the utility of TDM of biologics in IBD, specifically for reactive and proactive TDM of anti-tumor necrosis factors.

Systematic Review and Principal Components Analysis of the Immunogenicity of Adalimumab

BACKGROUND

The reported immunogenicity rates of adalimumab differ significantly between studies because of a wide variety of factors related to the disease, patients, study design, and products.

OBJECTIVE

The objective of this study was to characterize this variability and identify the major factors that contribute to these fluctuations.

METHODS

A systematic literature review was conducted using the MEDLINE, Clinicaltrials.gov, and Cochrane Library databases. Studies that reported the immunogenicity rates of adalimumab were selected, and data pertaining to publication details, study characteristics, characteristics of the cohort at baseline, and immunogenicity were extracted. Records were sorted according to the immunogenicity assay type, and mean immunogenicity values for each assay type were calculated. Normalised immunogenicity was calculated for each report by subtracting the appropriate mean immunogenicity value. Collected data were subjected to statistical analysis, namely analysis of variance (ANOVA) and principal component analysis, to unveil immunogenicity rate patterns across studies from a multivariate perspective.

RESULTS

In total, 130 publications were identified, from which 165 data records were extracted and included in the analysis. The immunogenicity rates of adalimumab averaged 24.9% across studies and varied significantly over time, ranging between 0 and 87%. An increase across time in the reported immunogenicity rates was detected, and the assay used to detect anti-adalimumab antibodies was a significant (but not exclusive) contributor to this trend. Furthermore, the principal components analysis revealed that the type of study and the exposure time were associated with the assay-normalised immunogenicity rates of adalimumab. Nonetheless, neither these nor the remaining factors included in this analysis seem to contribute to the temporal increase in reported immunogenicity rates.

CONCLUSIONS

Future studies that evaluate the patient-, product-, and disease-related factors behind the immunogenicity of adalimumab are required because the evidence published so far does not completely explain the temporal increase in immunogenicity rates detected in this analysis.

Optimization of azathioprine dose in combined treatment with anti-TNF-alpha in inflammatory bowel disease

INTRODUCTION

The dose of thiopurine drugs in combined treatments with anti-TNF in inflammatory bowel disease (IBD) has not been clearly established. The purpose of this study is to assess whether the dose of azathioprine influences clinical and biochemical response/remission rates, and anti-TNF drug levels/antibody formation.

MATERIAL AND METHODS

Patients with IBD on combined maintenance treatment with azathioprine and infliximab or adalimumab were selected. Based on the dose of azathioprine, two groups were defined (standard: 2-2.5mg/kg/day; and decreased: less than 2mg/kg/day).

RESULTS

In the IFX group, there were no statistically significant differences (p=0.204) in the rates of remission (39% vs 41.3%), response (10% vs 21.7%) or failure (51.5% vs 37%) depending on the dose of thiopurine drugs. No differences were found between AZA-dose dependent IFX levels (2.46 vs 3.21μg/mL; p=0.211). In the adalimumab group, there were no statistically significant differences (p=0.83) in the rates of remission (66% vs 56%), response without remission (15.38% vs 25%) or failure (18% vs 18%) depending on the dose of thiopurines. With respect to ADA-levels, no differences were found in both groups (7.69 vs 8.23μg/mL; p=0.37).

CONCLUSION

In our experience, no statistically significant differences were found in either anti-TNF levels or clinical-biological response/remission rates based on doses of azathioprine.

INDUCTION THERAPEUTIC DRUG MONITORING REGIMEN WITH INFLIXIMAB: A SIMPLIFIED EVIDENCE-BASED ALGORITHM FOR INFLAMMATORY BOWEL DISEASE

Therapeutic drug monitoring (TDM) of infliximab (IFX) has been recognized as an important strategy in the management of secondary loss of response to this agent, guiding clinical decision-making in the management of inflammatory bowel diseases (IBD). Although most of the data on the application of TDM for IFX refer to the maintenance phase of treatment, many studies have associated higher drug concentrations, specially in the induction phase, with achievement of important treatment targets, such as clinical remission and mucosal healing. This brief communication aims to summarize the literature on the use of TDM during induction phase of IFX and propose application of a simplified approach which can be useful into clinical practice, aiming better outcomes to IBD patients.

Therapeutic Drug Monitoring of Biologics During Induction to Prevent Primary Non-Response

Biologic therapies have revolutionized the management of inflammatory bowel disease [IBD], but primary and secondary non-responses occur in a significant proportion of patients. Therapeutic drug monitoring [TDM] now has an established role in the treatment algorithm for managing secondary loss of response to anti-tumour necrosis factor [anti-TNF] agents during maintenance therapy. Data to support the use of TDM in the management of secondary loss of response to vedolizumab and ustekinumab are emerging. The potential to prevent primary non-response to biologic agents during induction is of equal, and potentially greater, clinical importance. Again, most data supporting the use of 'proactive' TDM during induction pertains to the use of anti-TNF agents, but signals of efficacy for the use of TDM during induction with other biologic classes are now appearing. This review aims to summarize data on the use of TDM during induction to prevent pharmacokinetic primary non-response to all three classes of biologic therapy currently available for the treatment of IBD.

Comparison of Serum Concentrations of Ustekinumab Obtained by Three Commercial Assays in Patients with Crohn's Disease

Background

Data on the association of ustekinumab (UST) drug concentrations and clinical outcomes are conflicting. We assessed serum UST drug and anti-UST antibody concentrations using three commercially available assays.

Methods

Sixty-one blood samples were analyzed for serum UST drug and anti-UST antibody concentrations using three assays: one homogeneous mobility shift assay (HMSA, Prometheus, Assay A), and two enzyme-linked immunosorbent assays (ELISA; Progenika, Dynacare, Assay B and Theradiag, Assay C).

Results

The median (IQR) serum UST concentrations for the three assays were: Assay A 7.50 (5.35 to 12.88) µg/mL, Assay B 4.02 (2.46 to 6.95) µg/mL and Assay C 4.35 (2.62 to 7.50) µg/mL. A Kruskal-Wallis test confirmed a statistically significant difference between the different assays, X²(2) = 30.606, p < 0.001. Linear regression showed near twofold increased difference in the absolute drug concentrations between the HMSA and either ELISA. Linear quantitative correlation was observed for all three assays (r = 0.836 for A versus B, r = 0.792 for A versus C, r = 0.936 for B versus C; p < 0.01). The intraclass correlation coefficient (ICC) between assay A and B was 0.649 (95% confidence interval [CI] -0.208 to 0.874); assay A and C was 0.671 (95% CI -0.165 to 0.878); and assay B and C was 0.958 (95% CI 0.928 to 0.975); p < 0.001. No anti-UST antibodies were detected.

Conclusion

A good correlation was observed for serum UST drug concentrations and a good agreement was observed between the ELISA tests. However, agreement was poor between the HMSA and each ELISA tests. Clinical recommendations regarding drug concentrations should be based on assay type used.

Review article: determination of the therapeutic range for therapeutic drug monitoring of adalimumab and infliximab in patients with inflammatory bowel disease

BACKGROUND

Clinical application of therapeutic drug monitoring (TDM) to optimise anti-TNF therapies in patients with IBD depends upon target ranges.

AIMS

To review methodology used to determine therapeutic ranges and critically compare and contrast its application to infliximab and adalimumab.

METHODS

A systematic review was performed, and relevant literature was summarised and critically examined.

RESULTS

Upper limits of the therapeutic range are determined by toxicity, a plateau response and cost. Lower limits are determined by optimal concentration on the target of action in vitro and/or in vivo, or by correlation of drug levels with clinical efficacy using area-under-receiver-operator-curve (AUROC) analysis. In 43 studies, there were huge variations in time at which infliximab and adalimumab levels were measured, the end-points used (clinical remission to mucosal healing), the clinical setting (active disease vs maintenance phase) and the reason for TDM (proactive vs reactive). In the maintenance phase for infliximab, lower trough limits 2.8-5.7 µg/mL are reported depending upon end-points used, with consistent AUROC 0.68-0.77. Adalimumab TDM targets are even less consistent with a lower limit 5.9-11.8 µg/mL (AUROC 0.66-0.83) in some studies, but no cut-off can be identified that is significantly associated with outcome in others, related to inherent pharmacokinetic and pharmacodynamic differences, and heterogeneity of study design.

CONCLUSIONS

Evidence for exposure-response relationship is stronger for infliximab than adalimumab. Due to heterogeneity in settings for drug level measurements, therapeutic ranges vary. These factors need to be taken into account when interpreting the evidence and extending this to therapeutic strategies for IBD patients.

Factors Influencing Drug Disposition of Monoclonal Antibodies in Inflammatory Bowel Disease: Implications for Personalized Medicine

Monoclonal antibody (mAb) therapies have revolutionized the treatment of several chronic inflammatory diseases, including the inflammatory bowel diseases (IBD), Crohn's disease, and ulcerative colitis. While efficacious, responses to these therapies vary considerably from patient to patient, due in part to inter- and intra-individual variability in pharmacokinetics (PK) and drug exposure. The concept of personalized medicine to monitor drug exposure and to adjust dosing in individual patients is consequently gaining acceptance as a powerful tool to optimize mAb therapy for improved outcomes in IBD. This review provides a brief overview of the different mAbs currently approved or in development for the treatment of IBD, including their presumed mechanisms of action and PK properties. Specifically described are (1) the factors known to affect mAb PK and drug exposure in patients with IBD, (2) the value of population PK/pharmacodynamic (PD) modeling to identify and understand the influence of these factors on drug exposure and effect, and (3) the clinical evidence for the potential of therapeutic drug monitoring (TDM) to improve IBD outcomes in response to mAb-based therapy. Incorporation of PK/PD parameters into clinical decision support tools has the potential to guide therapeutic decision making and aid implementation of personalized medicine strategies in patients with IBD.

Intraocular Inflammation Control and Changes in Retinal and Choroidal Architecture in Refractory Non-Infectious Uveitis Patients after Adalimumab Therapy

Background: Non-infectious uveitis represents a leading cause of visual impairment, and inflammation control represents a major priority in tackling visual acuity loss due to complications such as macular edema; different immunomodulatory drugs are currently being used, including anti-TNF-alpha Adalimumab. Methods: This was a monocentric observational study of 18 eyes of 18 patients with non-infectious uveitis treated with Adalimumab. The primary endpoint was the control of ocular inflammation. The secondary endpoints included the study of macular and choroidal thickness and architecture, visual acuity, changes in other treatments, and adverse effects. Results: Ocular inflammation was controlled at 12 months for 83.3% of patients. Central macular thickness improved from a median of 229.75 µm at baseline to 213 µm at 12 months, while choroidal thickness decreased by 11.54% at the end of the follow-up. A reduction of vasculitis on fluorescein angiography and of hyperreflective spots on optical coherence tomography was noted. Visual acuity also improved from 0.51 (logMAR) before treatment to 0.24 at more than 12 months (p = 0.01). A total of 11.1% of patients experienced side effects. Conclusion: Our study confirms the efficacy of adalimumab for the control of ocular inflammation, visual acuity preservation, and for corticosteroid sparing.

A nationwide survey on therapeutic drug monitoring of anti-tumour necrosis factor agents for inflammatory bowel disease

BACKGROUND

Routine therapeutic drug monitoring (TDM) during treatment with anti-tumour necrosis factor (anti-TNF) agents in inflammatory bowel disease may increase treatment efficacy and cost-effectiveness, and reduce the risk of loss of response.

AIMS

To assess the current use of anti-TNF agent TDM, including trough concentration and anti-drug antibodies, among gastroenterology practitioners in New Zealand.

METHODS

A web-based survey was delivered to gastroenterologists and advanced trainees in New Zealand, identified by the New Zealand Society of Gastroenterology.

RESULTS

The response rate was 36% (48/134). Adalimumab was the most common initial anti-TNF agent used (78%, infliximab 22%). Ninety-three percent of those who completed the survey used TDM, mainly in cases of non-response or loss or response. Most respondents (93% and 83% for adalimumab and infliximab, respectively) measured trough concentrations within 24 h prior to the next administration. In patients in clinical remission but with endoscopic inflammation on anti-TNF agents, 72% would measure drug concentrations. In the presence of anti-drug antibodies, 45% would add an immunomodulator in patients with active disease and 47% would add an immunomodulator in patients in remission. With low trough concentrations, 77% would make no changes if the patient was in remission, and 75% would increase the dose in case of active disease.

CONCLUSION

TDM was routinely used among inflammatory bowel disease gastroenterology clinicians who responded to this survey. However, interpretation of results and decision-making is variable, suggesting more guidance is required.

Early Adalimumab and Anti-Adalimumab Antibody Levels for Prediction of Primary Nonresponse in Ankylosing Spondylitis Patients

This study aimed at exploring the concentration‐effect relationship of adalimumab and early adalimumab and anti‐adalimumab antibody (AAA) levels in predicting primary nonresponse in a real‐world pilot cohort of patients with ankylosing spondylitis. Thirty‐one patients were included. The Ankylosing Spondylitis Disease Activity Score improved with increasing adalimumab trough level at week 12 and reached a major improvement with levels between 8 and 12 μg/mL. Moreover, weeks 4 and 2 adalimumab levels below 4.28 and 3.37 μg/mL were predictive of primary nonresponse (area under the curve (AUC) = 0.89, 0.88; P = 0.0003, P = 0.034, respectively). Week 4 AAA signal‐to‐noise levels were significantly higher among primary nonresponders, and the cutoff for primary nonresponse prediction was above 5.31 (AUC = 0.81; P = 0.004). Adalimumab trough levels in a range of 8–12 μg/mL are optimum to reach major improvement, and lower adalimumab with higher AAA levels at the early stage (week 4) predict primary nonresponse by supporting proactive monitoring to optimize adalimumab therapy.

Ulcerative Colitis: Shifting Sands

Ulcerative colitis (UC) is a chronic inflammatory bowel disease associated with considerable disease burden. We review some current misconceptions about UC in adults with the aim of optimizing care for patients. Although UC and Crohn's disease (CD) are considered discrete diseases, distinctions between them are not always clear-cut and phenotypes may change over time. Patient management should take into account disease manifestations, disease severity and extent, and response to prior treatments. Although disease extent often defines severity, distal UC is not always less disabling than extensive disease as patients can progress to more extensive disease. In addition, severe proctitis can give rise to severe and debilitating symptoms, with a substantial impact on health-related quality of life. UC carries an increased risk of colorectal cancer (CRC) compared with CD; however, more recent data indicate a similar risk of CRC in CD with colonic involvement as with UC. Corticosteroids are widely used to induce remission in UC, and prolonged use of steroids in patients with UC is common, but corticosteroid-free maintenance of remission is an important therapeutic goal. Although biologic therapies provide a valuable treatment option in UC, they are not clinically effective in all patients and are also associated with secondary loss of response.

Clinical Pharmacokinetic and Pharmacodynamic Considerations in the Treatment of Inflammatory Bowel Disease

According to recent clinical consensus, pharmacotherapy of inflammatory bowel disease (IBD) is, or should be, personalized medicine. IBD treatment is complex, with highly different treatment classes and relatively few data on treatment strategy. Although thorough evidence-based international IBD guidelines currently exist, appropriate drug and dose choice remains challenging as many disease (disease type, location of disease, disease activity and course, extraintestinal manifestations, complications) and patient characteristics [(pharmaco-)genetic predisposition, response to previous medications, side-effect profile, necessary onset of response, convenience, concurrent therapy, adherence to (maintenance) therapy] are involved. Detailed pharmacological knowledge of the IBD drug arsenal is essential for choosing the right drug, in the right dose, in the right administration form, at the right time, for each individual patient. In this in-depth review, clinical pharmacodynamic and pharmacokinetic considerations are provided for tailoring treatment with the most common IBD drugs. Development (with consequent prospective validation) of easy-to-use treatment algorithms based on these considerations and new pharmacological data may facilitate optimal and effective IBD treatment, preferably corroborated by effectiveness and safety registries.

Subcutaneous Absorption Contributes to Observed Interindividual Variability in Adalimumab Serum Concentrations in Crohn's Disease: A Prospective Multicentre Study

BACKGROUND AND AIM

Therapeutic drug monitoring is used to optimise adalimumab therapy in patients with Crohn's disease [CD]. However, the interindividual variability in drug absorption and the quantitative effect on drug clearance of anti-adalimumab antibodies [AAA], measured with a drug-resistant assay, are unclear. We aimed to characterise adalimumab population pharmacokinetics [PopPK] and identify determinants of interindividual variability in patients with CD.

METHODS

In a prospective multicentre open-label cohort study in 28 patients with CD starting adalimumab therapy peak, intermediate, and trough serum samples were analysed for adalimumab and AAA concentrations using a drug resistant assay. Adalimumab concentration-time data were analysed by non-linear mixed effects modelling and were adequately described by a PopPK model with first-order absorption and one-compartment disposition with linear elimination. Clinical remission at Week 12 [W12] was defined as a Harvey-Bradshaw index ≤4.

RESULTS

The absorption rate, volume of distribution, and clearance estimates of a typical patient were respectively 0.343 /day, 7.8 L, and 0.330 L/day. A 4-fold difference in the range of adalimumab concentrations was observed 7 days after the first dose and found to be inversely correlated with baseline lean body weight [LBW], soluble tumour necrosis factor [s-TNF], and s-TNF receptor-1 whereas positive AAA and higher LBW were found to be important predictors of accelerated clearance. An adalimumab concentration at W12 of >7.3 µg/mL was significantly associated with achieving clinical remission at W12.

CONCLUSION

Variability in subcutaneous drug absorption is an important contributor to the observed interindividual variability in adalimumab concentrations, in addition to drug clearance [ClinicalTrials.gov NCT02450513].

Earlier discontinuation of TNF-α inhibitor therapy in female patients with inflammatory bowel disease is related to a greater risk of side effects

BACKGROUND

In rheumatoid arthritis and psoriasis female sex has been shown to be associated with discontinuation of anti-tumour necrosis factor-α (TNF-α) therapy.

AIM

To retrospectively assess the association between sex and TNF-α drug persistence in patients with inflammatory bowel disease (IBD).

METHODS

All IBD patients on anti-TNF-α therapy with a minimum follow-up of 12 months in a single tertiary centre were identified. Patient and treatment characteristics and reasons for anti-TNF-α discontinuation were recorded. Overall and cause-specific drug persistence was analysed with Kaplan-Meier followed by Cox proportional hazards regression models.

RESULTS

We included 529 patients (49.9% male) with 631 treatment episodes (2280 anti-TNF-α treatment years) and 289 discontinuations of therapy. Female sex (adjusted hazard ratio [aHR] 1.42, 95% confidence interval [CI] 1.16-1.74), greater age at start of therapy per decade (aHR 1.15, 95% CI 1.04-1.27] and dose escalation (aHR 3.74, 95% CI 2.78-5.02) were associated with TNF-α inhibitor discontinuation. Total cohort cause-specific analysis identified female sex to be associated with side effects (aHR 4.05, 95% CI 2.36-6.98) but not to other discontinuation reasons. Adalimumab (aHR 1.70, 95% CI 1.11-2.60) and golimumab (aHR 4.97, 95% CI 2.30-10.74) use and dose-escalation (aHR 7.71, 95% CI 5.28-11.26) were associated with secondary loss of response.

CONCLUSION

Drug persistence of anti-TNF-α therapy is lower in females as compared to males, mainly because of higher rates of side effects in females. Understanding the sex specific differences in effectiveness and safety of anti-TNF-α compounds can aid physicians in clinical decision-making.

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.

Wide variation in the use and understanding of therapeutic drug monitoring for anti-TNF agents in inflammatory bowel disease: an inexact science?

BACKGROUND

We aimed to understand the way in which therapeutic drug monitoring (TDM) is used, understood and interpreted for anti-TNF agents in IBD.

RESEARCH DESIGN AND METHODS

We designed an 18-question survey that included 5 TDM-based clinical scenarios, for which the 'most appropriate' responses were based on the BRIDGe groups 'Anti-TNF Optimizer'. This resource combines TDM evidence with expert consensus.

RESULTS

We received 110 complete responses: 50 (45%) consultants, 30 (27%) trainees, 25 (23%) IBD nurse specialists and 5 (5%) gastroenterology pharmacists. Over half (61, 55%) only carry out TDM in non-response. The remainder use TDM routinely, including during stable maintenance therapy for patients in remission. Lower therapeutic thresholds used were variable. Most (82, 75%) were unsure whether their laboratory uses a drug-tolerant or drug-sensitive antidrug antibody assay and few (15, 14%) understand the difference. Consultants, high-frequency users (> 3requests/month) and clinicians with larger anti-TNF cohorts (> 100) were significantly more likely to select the 'most appropriate' answer to at least 1 of the 5 TDM-based clinical scenarios.

CONCLUSIONS

There exists marked heterogeneity in the practical use, understanding and interpretation of biologic TDM. Biologic decision-making, informed by TDM, should involve consultation with experienced clinicians who are frequent TDM users, ideally, as part of a multidisciplinary, biologics-focused IBD meeting.

ABBREVIATIONS

TDM: therapeutic drug monitoring; CNS: clinical nurse specialist; ELISA: enzyme-linked immunosorbent assay; RIA: radioimmunoassays; HMSA: homogenous mobility shift assays; BSG: British Society of Gastroenterology.

Reversal of Immunogenicity in Pediatric Inflammatory Bowel Disease Patients Receiving Anti-Tumor Necrosis Factor Medications

Loss of response to anti-tumor necrosis factor (anti-TNF) agents in the treatment of inflammatory bowel disease (IBD) is a major consideration to maintain sustained response. Reversal of immunogenicity can re-establish response and increase the durability of these agents. Strategies to reverse immunogenicity include dose-intensification and/or the addition of an immunomodulator. However, there is a relative paucity of data on the efficacy of such interventions in pediatric IBD patients. Available reports have not strictly utilized homogenous mobility shift assay, which reports on anti-drug antibodies even in the presence of detectable drug, whereas prior studies have been confounded by the use of drug sensitive assays. We report four pediatric inflammatory bowel disease patients with successful reversal of immunogenicity on an anti-TNF agent using dose intensification and/or addition of an immunomodulator.

Influence of early adalimumab serum levels on immunogenicity and long-term outcome of anti-TNF naive Crohn's disease patients: the usefulness of rapid testing

BACKGROUND

Proactive testing of adalimumab serum levels is debated.

AIM

To study the association between adalimumab serum levels at week 4 and the development of anti-adalimumab drug antibodies and long-term outcome in anti-TNF naive Crohn's disease patients.

METHODS

Serum samples from 116 biologically naive Crohn's disease patients with active disease were prospectively collected at baseline, and weeks 4 and 12. Adalimumab serum levels were measured using the RIDA^® QUICK adalimumab lateral flow assay and anti-adalimumab drug antibodies were determined using a drug-resistant assay. Pharmacokinetic data were studied in relation to clinical outcome. Patients who stopped adalimumab by week 12 due to persisting symptoms were considered primary non-responders, whereas initial improvement with increasing symptoms after week 12 was considered loss of response. Adalimumab continuation until the end of follow-up was considered sustained clinical benefit.

RESULTS

Patients with low serum levels at week 4 (<8.3 μg/mL) were at significantly higher risk of being anti-adalimumab positive by week 12 (46.7% vs 13.0%, P = 0.009). After a median follow-up of 89 weeks, dose-escalation and sustained clinical benefit were observed in 37.1% and 48.3% of patients. The 21.4% of patients who were anti-adalimumab drug antibody positive by week 12, had a significantly higher need of dose escalation (P < 0.001), and experienced sustained clinical benefit less frequently due to primary non-response or secondary loss of response (P = 0.02).

CONCLUSIONS

Our findings support early monitoring of adalimumab serum levels to guide dose optimisation, which may prevent immunogenicity and influence long-term outcome. We validated a novel lateral flow assay for quantitative determination of adalimumab levels, facilitating physicians to optimise therapy immediately at the outpatient clinic.

Proactive Therapeutic Drug Monitoring of TNF Antagonists in Inflammatory Bowel Disease

BACKGROUND

Proactive therapeutic drug monitoring (TDM) to titrate tumor necrosis factor (TNF) antagonists has emerged recently as a tool to routinely monitor drug concentration to achieve target levels in patients with quiescent inflammatory bowel disease (IBD).

METHODS

The purpose of the present review article was to present available data exploring the concept of proactive TDM.

RESULTS

While several observational studies have identified an association between proactive TDM and better IBD outcomes, 2 randomized controlled studies did not confirm this advantage.

CONCLUSIONS

Based on the evidence to date, proactive TDM cannot be recommended in daily practice. However, analysis is hampered by the low level of evidence for the cutoffs used and the need for point-of-care assays. Regarding economic issues and de-escalating strategies, proactive TDM may have several future indications in IBD. Exploratory studies on proactive TDM with newly available biologic agents in IBD are also awaited.

Ustekinumab in the management of Crohn's disease: Expert opinion

This expert-opinion paper reviews available evidence for the use of ustekinumab, a human interleukin 12/23 monoclonal antibody, in the treatment of Crohn's disease and discusses its potential role in the current treatment scenario for the condition. Ustekinumab appears to be associated with rapid and sustained clinical effect, as reported from the clinical research program, with additional support for potential mucosal healing. These characteristics are paralleled by a favorable safety profile, lack of immunogenicity and the presence of systemic anti-inflammatory activity. Importantly, ustekinumab requires only one single intravenous administration, while subsequent dosing is administered subcutaneously, with potential advantages for home-based therapy. Lastly, the dosage of ustekinumab is flexible. On the basis of the evidence, ustekinumab has a role in patients with primary failure or secondary loss of response to anti-tumor necrosis factor agents, as well as in those who have adverse events on front-line biologics or are reinitiating therapy after a treatment holiday. Current evidence suggests that ustekinumab may be particularly suitable in patients who present extra-intestinal manifestations of the disease or are at risk of infections. Ustekinumab may also be considered in the first-line setting, especially in frail patients, in young subjects or in those who have concomitant immune-mediated diseases.

Interactions Between Thiopurine Metabolites, Adalimumab, and Antibodies Against Adalimumab in Previously Infliximab-Treated Patients with Inflammatory Bowel Disease

BACKGROUND

Interactions between thiopurines and infliximab presumably contribute to superior effect of infliximab-thiopurine combination therapy in patients with inflammatory bowel disease (IBD). We examined whether principal cytotoxic thiopurine metabolites influence adalimumab (ADL) and anti-ADL antibodies (Abs).

METHODS

Ninety-eight IBD patients previously treated with infliximab (96%) in whom trough ADL and anti-ADL Abs had been assessed as part of their clinical care were included. Thiopurine metabolites [6-thioguanine nucleotides (6-TGN) and methylated mercaptopurine metabolites (6-MeMP)] were determined at similar time points.

RESULTS

ADL-thiopurine combination therapy was not associated with reduced anti-ADL Ab positivity compared to ADL monotherapy: 8/31 (26%) versus 19/67 (28%), p = 1.00. Concentrations of thiopurine metabolites were similar in anti-ADL Ab-positive and negative patients (6-TGN median 109 pmol/8 × 10⁸ RBC vs. 112, p = 0.80; 6-MeMP 448 RBC vs. 720, p = 0.94). ADL trough levels did not differ between anti-ADL Ab-negative patients on ADL-thiopurine combination therapy and those on monotherapy (9.5 μg/mL vs. 7.6, p = 0.31). ADL levels were also comparable between patients on ADL mono- and combination therapy after stratification for 6-TGN/6-MeMP quartiles. There were no correlations between levels of 6-TGN and ADL (r_P = - 0.17, p = 0.45; r_S = - 0.38, p = 0.08), or 6-MeMP and ADL (r_P = - 0.23, p = 0.31; r_S = - 0.35, p = 0.11). Anti-ADL Ab positivity was associated with ADL treatment failure (OR 6 [2-20], p < 0.01). Higher trough ADL (9.6 μg/mL vs. 7.3, p < 0.05), but not concomitant thiopurine treatment, metabolite levels, or dosage, was associated with clinical remission.

CONCLUSION

Effectiveness of ADL therapy associated with circulating ADL levels and anti-ADL Ab formation. In this study, there appeared no direct interactions between thiopurine metabolites and ADL or anti-ADL Abs.

Prospective Observational Evaluation of Time-Dependency of Adalimumab Immunogenicity and Drug Concentrations: The POETIC Study

OBJECTIVES

Adalimumab is usually self-injected at home, making prospective serial-sampling studies challenging and scarce. This has led to a gap in knowledge about evolution of anti-adalimumab antibodies (AAAs) over time and its correlation with clinical and inflammatory outcomes.

METHODS

A program for home visits by physicians at induction, every 3 months and at event of relapse, was established prospectively for Crohn's disease (CD) patients. At each visit, patients' clinical scores were determined and sera were obtained for C-reactive protein, drug, and AAA levels. This cohort was compared to a parallel prospective cohort of infliximab-treated CD patients. In a subgroup of 29 patients, trough and in-between-trough levels were compared, to elucidate the importance of timing of sampling during the injection cycle.

RESULTS

Ninety-eight CD patients starting adalimumab were prospectively followed (median follow-up 44 weeks) and 621 serum samples were analyzed. Thirty-three patients (32%) developed AAA; 18/33 (55%) of them as early as week 2, and 26/33 (79%) by week 14. Induction period AAAs were strongly associated with primary non-response (odds ratio (OR) = 5.4, 95% confidence interval (CI): 1.6-17.8, p = 0.005). As compared to antibodies-to-infliximab (ATI), AAA formation rate over time was significantly lower (p = 0.01) and AAA were much more specific-85% of AAA events were associated with loss-of-response compared with 58% rate for ATI (p = 0.01). In 29 patients sampled serially during an injection cycle, levels of drug and AAA seemed comparable between four time-points during a single cycle both in patients with or without AAA (n = 8, n = 21, respectively).

CONCLUSIONS

When followed prospectively and serially, AAAs are found to arise earlier than previously appreciated and their impact may be more pronounced for primary rather than secondary, non-response. Drug and AAA levels were similar both at trough and in-between injections, enabling to simplify therapeutic drug monitoring of adalimumab.

Immunoassay methods used in clinical studies for the detection of anti-drug antibodies to adalimumab and infliximab

We examined the assay formats used to detect anti-drug antibodies (ADA) in clinical studies of the anti-tumour necrosis factor (TNF) monoclonal antibodies adalimumab and infliximab in chronic inflammatory disease and their potential impact on pharmacokinetic and clinical outcomes. Using findings of a recent systematic literature review of the immunogenicity of 11 biological/biosimilar agents, we conducted an ancillary qualitative review of a subset of randomized controlled trials and observational studies of the monoclonal antibodies against anti-TNF factor adalimumab and infliximab. Among studies of adalimumab and infliximab, the immunoassay method used to detect antibodies was reported in 91 of 111 (82%) and 154 of 206 (75%) adalimumab and infliximab studies, respectively. In most adalimumab and infliximab studies, an enzyme-linked immunosorbent assay or radioimmunoassay was used [85 of 91 (93%) and 134 of 154 (87%), respectively]. ADA incidence varied widely among assays and inflammatory diseases (adalimumab, 0-87%; infliximab, 0-79%). Pharmacokinetic and clinical outcomes were only reported for ADA-positive patients in 38 of 91 (42%) and 61 of 154 (40%) adalimumab and infliximab studies, respectively. Regardless of assay format or biological used, ADA formation was associated with lower serum concentrations, reduced efficacy and elevated rates of infusion-related reactions. Consistent with previous recommendations to improve interpretation of immunogenicity data for biologicals, greater consistency in reporting of assay methods and clinical consequences of ADA formation may prove useful. Additional standardization in immunogenicity testing and reporting, application of modern, robust assays that satisfy current regulatory expectations and implementation of international standards for marketed products may help to improve our understanding of the impact of immunogenicity to biologics.

Immunogenicity of Therapeutic Antibodies: Monitoring Antidrug Antibodies in a Clinical Context

One of the factors that may impact drug levels of therapeutic antibodies in patients is immunogenicity, with potential loss of efficacy. Nowadays, many immunogenicity assays are available for testing antidrug antibodies (ADA). In this article, we discuss different types of immunogenicity assays and their clinical relevance in terms of drug tolerance, relation with pharmacokinetics (PK), neutralizing antibodies, potential adverse events associated with ADA, and prediction of ADA production. Drug-tolerant assays can provide insight into the process of immunogenicity, but for clinical management, these assays do not necessarily outperform drug-sensitive assays. The usefulness of any ADA assay for clinical decision making will be larger when drug concentrations are also measured, and this is true, in particular, for drug-tolerant assays.

Efficacy of a concomitant elemental diet to reduce the loss of response to adalimumab in patients with intractable Crohn's disease

BACKGROUND AND AIM

Secondary loss of response to adalimumab (ADA-LOR) commonly occurs in patients with Crohn's disease (CD) treated with adalimumab (ADA). We evaluated the efficacy of concomitant elemental diet (ED) therapy to reduce ADA-LOR in adult CD patients.

METHODS

Patients were divided into either an ED (≥900 kcal/day) or a non-ED group (<900 kcal/day). Cumulative non-ADA-LOR rates were compared between groups. The effects of ED intake to reduce ADA-LOR were also assessed in antitumor necrosis factor-alpha (TNF-α)-naïve and infliximab (IFX)-intolerant or refractory CD patients. Serum ADA and TNF-α levels were measured.

RESULTS

We enrolled 117 CD patients into the ED (n = 25) or non-ED (n = 92) groups. Although the cumulative non-ADA-LOR rate was higher in the ED group than in the non-ED group, ED intake was not an independent reducing factor for ADA-LOR (adjusted hazard ratio = 0.725; 95% confidence interval: 0.448-1.180; P = 0.196) in all patients. ED intake was significantly more effective in reducing ADA-LOR in IFX-intolerant or refractory patients than in anti-TNF-α-naïve patients in a dose-related manner (P for interaction <0.20). Serum ADA levels did not differ between the groups. Serum TNF-α levels were significantly lower in the ED group than in the non-ED group at week 28 (P = 0.044) and week 52 (P = 0.043).

CONCLUSIONS

Concomitant ED therapy reduced ADA-LOR in IFX-intolerant or refractory patients in a dose-related manner. Reductions in the TNF-α levels by concomitant ED intake may contribute to reduce ADA-LOR in CD patients.

Exploring conditions for redistribution of anti-tumor necrosis factors to reduce spillage: A study on the quality of anti-tumor necrosis factor home storage

BACKGROUND AND AIM

Biologicals are potent drugs for immune-mediated inflammatory diseases. After discontinuation or switch of therapy, many patients have unused biological injectors left. This study aimed to evaluate potential redistribution of unused injectors to prevent spillage of these costly drugs by assessing (i) the quality of transport and home storage through the proportion of injectors stored within the recommended temperature range (2-8 °C) and (ii) acceptance of redistribution by patients.

METHODS

All golimumab users, irrespective of the indication, at Maastricht University Medical Center were eligible for inclusion. Patients received golimumab in a sealed bag containing a validated temperature sensor, measuring temperature every 5 min. Patients were asked to store their medication as usual. Deviations from the recommended range were defined as any duration below 0 °C and > 30 min below 2 °C or above 8 °C. After 3 months, patients completed a questionnaire on their opinion towards potential redistribution of unused biologicals.

RESULTS

Fifty patients (42.0% male, mean age 53.2 ± 14.3 years) received 276 injectors. The mean storage time was 30.9 ± 33.1 days. Only 11.6% of the injectors were stored within the recommended temperature range. In addition, 11.2% were stored > 30 min below 0 °C and 33.2% were stored > 1 week above 8 °C. Of all patients, 95% would accept redistributed medication when product quality is ensured.

CONCLUSIONS

During transport and home storage, only one in eight biological injectors was stored within the recommended temperature range. This hinders redistribution of unused injectors but also raises concern regarding drug effectiveness in immune-mediated inflammatory disease patients.

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).

Positive relationship between infliximab and adalimumab trough levels at completion of induction therapy with clinical response rates, at a tertiary referral center

BACKGROUND AND AIM

Anti-tumor necrosis factor alpha (TNFα) therapies have improved outcomes for patients with inflammatory bowel disease. The aim of this study was to explore the relationship between infliximab (IFX) and adalimumab (ADL) trough and antibody levels with clinical response rates at the end of induction.

METHODS

This was a prospective, single-center study. Patients were recruited from July 2015 to August 2016. Inclusion criteria were all inflammatory bowel disease patients older than 17 years who started treatment with IFX or ADL. Baseline clinical disease activity indexes were performed. Clinical response was defined as HBI ≤3 or partial Mayo score ≤4% or <30% reduction from baseline. Anti-TNFα trough and antibody levels were measured using standard ELISA techniques.

RESULTS

Thirty-five patients were recruited, of whom 23 had Crohn's disease and 12 had ulcerative colitis. Eighteen were treated with ADL and 17 with IFX. The mean age of the cohort was 40.3 years, 62.9% were females, 34.3% were on concomitant thiopurines, and 25.7% had prior anti-TNFα exposure. Overall response rate was 51.4%, 33.3% for ADL and 70.6% for IFX.Mean trough levels were 12.5 μg/mL for IFX and 4.4 μg/mL for ADL. There was a clear link between higher anti-TNFα trough levels at the end of induction with clinical response rates. For IFX, mean trough level was 16.4 μg/mL for responders versus 5.3 μg/mL for non-responders (P = 0.026). Area under the curve for association of IFX level at induction with clinical response was 0.864 (P = 0.0001). Similar link was present between higher ADL levels with clinical response, although not statistically significant.

CONCLUSION

Higher trough levels at the end of induction are associated with improved response. Ongoing work will define optimal targets at this key timeframe.

Therapeutic Drug Monitoring During Induction of Anti-Tumor Necrosis Factor Therapy in Inflammatory Bowel Disease: Defining a Therapeutic Drug Window

Anti-tumor necrosis factor (TNF) therapy has revolutionized the treatment of inflammatory bowel disease (IBD). However, up to 30% of patients with IBD show no clinical benefit and are defined as having a primary nonresponse. Primary nonresponse to a biologic can be attributed to either pharmacokinetic or pharmacodynamic issues, such as those involved in secondary loss of response. Pharmacokinetic issues are linked to undetectable or subtherapeutic drug concentrations because of either an accelerated non-immune-mediated clearance or immunogenicity and the development of antidrug antibodies, whereas pharmacodynamic issues are likely related to "non-TNF driven" disease. Therapeutic drug monitoring (TDM), defined as the evaluation of drug concentrations and antidrug antibodies, has been proven effective for optimizing anti-TNF therapy in IBD. Nevertheless, most of the data for TDM relate to patients losing response during maintenance therapy, whereas much less is known about the therapeutic drug window and use of TDM during anti-TNF induction therapy. Recent exposure-response relationship studies, though, demonstrate that high serum anti-TNF drug concentrations during and early after induction therapy are associated with favorable therapeutic outcomes in IBD. This suggests that early optimization of anti-TNF therapy may prevent some of the primary nonresponse related to pharmacokinetic issues (low drug concentrations) and lead to better short- and long-term outcomes. This review will focus on the role of TDM during the induction phase of anti-TNF therapy.

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.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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