Comparison of a new rapid method for determination of serum anti-adalimumab and anti-infliximab antibodies with two established ELISA kits

Evaluating the Accuracy and Clinical Utility of AFIAS-10 Point of Care Versus Enzyme-Linked Immunosorbent Assay in Therapeutic Drug Monitoring of Infliximab and Adalimumab

BACKGROUND

New point-of-care (POC) techniques offer rapid results and address some of the limitations of traditional enzyme-linked immunosorbent assay (ELISA) methods, such as lengthy processing times and delays in therapeutic decision making. It is crucial to evaluate the comparability of POC assays with established ELISA methods to ensure accuracy and reliability in therapeutic drug monitoring. This study aimed to evaluate the analytical performance and clinical utility of the AFIAS-10 POC assay compared with the Promonitor ELISA for quantifying serum concentrations of infliximab (IFX) and adalimumab (ADA) and detecting antidrug antibodies (ATIs and ATAs).

METHODS

A prospective study was conducted from October 2023 to April 2024, including 225 samples from patients with immune-mediated diseases. The samples were analyzed using both AFIAS-10 POC and Promonitor ELISA assays. To assess the agreement between the 2 methods in terms of quantification, Bland-Altman analysis was performed by examining the mean difference and establishing limits of agreement.

RESULTS

The Pearson correlation coefficient indicated strong correlations for IFX (r = 0.932) and ADA (r = 0.967) between the 2 assays. The mean difference between POC and ELISA for IFX was -0.78 mcg/mL and for ADA was 1.54 mcg/mL, respectively. The POC assay tended to underestimate IFX concentrations and overestimate ADA concentrations compared with ELISA.

CONCLUSIONS

The AFIAS-10 POC assay demonstrated good correlation and concordance with the ELISA method for the quantification of IFX and ADA, as well as for detecting anti-IFX and anti-ADA antibodies. However, this correlation was notably lower at higher drug concentrations.

Impact of HLA-DQA1*05 Genotype in Immunogenicity and Failure to Treatment with Tumour Necrosis Factor-alpha Antagonists in Inflammatory Bowel Disease: A Systematic Review and Meta-analysis

BACKGROUND

HLA-DQA1*05 carriage has been associated with an increased risk of immunogenicity in patients with immune-mediated inflammatory diseases treated with tumour necrosis factor-alpha [TNF-a] antagonists. Results have shown an inconsistent association with a loss of response [LOR] in patients with inflammatory bowel disease [IBD], which could be modified when using proactive optimisation and association with immunomodulatory drugs.

AIMS

To define the association of HLA-DQA1*05 on anti-drug antibody development and loss of response [LOR] to anti-TNF-a in IBD.

METHODS

We searched MEDLINE, EMBASE, and SCOPUS, for the period up to August 2023, to identify studies reporting the risk of immunogenicity and/or LOR in IBD patients with HLA-DQA1*05 genotype.

RESULTS

A total of 24 studies comprising 12 papers, 11 abstracts and one research letter, with a total of 5727 IBD patients, were included. In a meta-analysis of 10 studies [2984 patients; 41.9% with HLA-DQA1*05 genotype], HLA-DQA1*05 carriers had higher risk of immunogenicity compared with non-carriers (risk ratio, 1.54; 95% confidence interval [CI], 1.23 - 1.94; I2 = 62%) [low certainty evidence]. Lack of therapeutic drug monitoring [TDM] increased immunogenicity in the presence of risk human leukocyte antigen [HLA] [risk ratio 1.97; 95% CI, 1.35 - 2.88; I2 = 66%], whereas proactive TDM revoked this association [very low certainty of evidence]. A meta-analysis of six studies [765 patients] found that risk for secondary LOR was higher among HLA-DQA1*05 carriers [hazard ratio 2.21; 95% CI, 1.69 - 2.88; I2 = 0%] [very low certainty evidence], although definition and time to assessment varied widely among studies.

CONCLUSION

HLA-DQA1*05 carriage may be associated with an increased risk of immunogenicity and secondary LOR in IBD patients treated with TNF-a antagonists.

ELISA assay for the quantification of ipilimumab in human serum, plasma, milk, and cerebrospinal fluid

Ipilimumab is an immune checkpoint inhibitor of the cytotoxic T-lymphocyte-associated protein 4 (CTLA-4). Ipilimumab has become part of the standard of care for different types of cancer. The efficacy of these treatments is limited due to immune-related toxicity and high economic costs. Dose rationalization studies based on pharmacokinetic data may help to address these limitations. For this purpose, more sensitive analytical methods are needed. We report the development and validation of the first enzyme-linked immunosorbent assay (ELISA) for sensitive determination of ipilimumab concentrations in human serum, plasma, cerebrospinal fluid (CSF), and milk. Our assay is based on the specific capture of ipilimumab by immobilized CTLA-4. The lower limit of quantifications of ipilimumab in serum, plasma, and milk are 50 ng/mL and 10 ng/mL in CSF. The ELISA method showed long-term storage stability for at least one year at -80°C and was successfully cross-validated with ultraperformance liquid chromatography coupled with tandem mass spectrometry. The ELISA method is reliable, relatively inexpensive, and can be used in serum, plasma, CSF, and milk from patients treated with ipilimumab, as evidenced by the analysis of real clinical samples.

Therapeutic drug monitoring in inflammatory bowel diseases. Position statement of the Spanish Working Group on Crohn's Disease and Ulcerative Colitis

The treatment of inflammatory bowel disease has undergone a significant transformation following the introduction of biologic drugs. Thanks to these drugs, treatment goals have evolved from clinical response and remission to more ambitious objectives, such as endoscopic or radiologic remission. However, even though biologics are highly effective, a significant percentage of patients will not achieve an initial response or may lose it over time. We know that there is a direct relationship between the trough concentrations of the biologic and its therapeutic efficacy, with more demanding therapeutic goals requiring higher drug levels, and inadequate exposure being common. Therapeutic drug monitoring of biologic medications, along with pharmacokinetic models, provides us with the possibility of offering a personalized approach to treatment for patients with IBD. Over the past few years, relevant information has accumulated regarding its utility during or after induction, as well as in the maintenance of biologic treatment, in reactive or proactive strategies, and prior to withdrawal or treatment de-escalation. The aim of this document is to establish recommendations regarding the utility of therapeutic drug monitoring of biologics in patients with inflammatory bowel disease, in different clinical practice scenarios, and to identify areas where its utility is evident, promising, or controversial.

Observational Study to Compare Biological Drug Concentration Quantification Techniques and Immunogenicity in Patients with Immune-Mediated Diseases

Measuring biological drugs' trough concentrations and the concentrations of anti-drug antibodies is a valuable practice for treatment optimization. ELISA techniques are the gold standard for biological drug concentration quantification, but new techniques such as chemiluminescence immunoassays present some advantages. The aim of this unicentric prospective observational study is to compare the infliximab, adalimumab, vedolizumab and ustekinumab trough levels and anti-adalimumab and anti-infliximab antibodies concentrations obtained when using a chemiluminescent instrument (i-TRACK®, Theradiag, Croissy-Beaubourg, France) and an ELISA instrument (TRITURUS®, Griffols, Barcelona, Spain). Linear regression, Pearson or Spearman tests, Bland-Altman plots and the Cohen kappa test were applied for every sample. The correlation was excellent for both assays in the measurement of all drug concentrations. In general, values were lower when measured using i-TRACK than when using TRITURUS, especially when the values were high. Both techniques proved valuable in clinical practice for monitoring adalimumab and infliximab drug concentration. However, the results were modest for ustekinumab and vedolizumab, so caution is recommended and further research is needed. The limited number of anti-drug antibody-positive samples precluded a comparison between the techniques.

Update on the systemic management of noninfectious uveitis in children and adolescents

Noninfectious uveitis (NIU) in children and adolescents is a rare but treatable cause of visual impairment in children. Treatments for pediatric NIU and their side effects, along with the risks of vision loss and the need for long-term disease monitoring, pose significant challenges for young patients and their families. Treatment includes local and systemic approaches and this review will focus on systemic therapies that encompass corticosteroids, conventional synthetic disease-modifying antirheumatic drugs (csDMARD), and biological disease-modifying antirheumatic drugs (bDMARD). Treatment is generally planned in a stepwise approach. Methotrexate is well-established as the preferential csDMARD in pediatric NIU. Adalimumab, an antitumor necrosis factor (TNF) agent, is the only bDMARD formally approved for pediatric NIU and has a good safety and efficacy profile. Biosimilars are gaining increasing visibility in the treatment of pediatric NIU. Other bDMARD with some evidence in literature for the treatment of pediatric NIU include infliximab, tocilizumab, abatacept, rituximab and, more recently, Janus kinase inhibitors. Important aspects of managing children on these systemic therapies include vaccination issues, risk of infection, and psychological distress. Also, strategies need to address regarding primary nonresponse/secondary loss of response to anti-TNF treatment, biological switching, and monitoring regimens for these drugs. Optimal management of pediatric uveitis involves a multidisciplinary team, including specialist pediatric uveitis and rheumatology nurses, pediatric rheumatologists, psychological support, orthoptic and optometry support, and play specialists.

Enhancing Therapeutic Drug Monitoring in Inflammatory Bowel Disease: A Comparative Analysis of Rapid Point-of-Care Infliximab, Adalimumab and Anti-Drug Antibodies' Determination against ELISA

The introduction of point-of-care (POC) assays into clinical practice in patients with inflammatory disease enables on-demand therapeutic decision making. The aim of this study was to compare the POC test Quantum blue (Bühlmann Laboratories) for infliximab (IFX), adalimumab (ADL), and its anti-drug antibodies with the traditional ELISA assay (Promonitor). A total of 200 serum samples were analyzed. Samples were classified into the following three different groups; sub-therapeutic range (IFX < 3 μg/mL and ADL < 5 μg/mL); therapeutic range (IFX: 3-7 μg/mL and ADL: 5-12 μg/mL) and supra-therapeutic range (IFX levels > 7 μg/mL and ADL levels > 12 μg/mL). Significant higher values were measured using the POC test (p < 0.001) for IFX results but no differences in ADL trough levels were observed (p = 0.3101). Spearman's correlation indicated a good correlation between the two assays (rs = 0.88 for ADL and rs = 0.93 for IFX), and McNemar's test revealed significant differences (p = 0.016) when classifying IFX samples between therapeutic and supra-therapeutic ranges but no significant differences were found among the other ranges for either IFX or ADL. These results show that we should be cautious when using these rapid measurement methods, and new targets should probably be defined for IFX when using this new analytical method.

Comparative Evaluation of Four Commercially Available Immunoassays for Therapeutic Drug Monitoring of Infliximab and Adalimumab

Therapeutic drug monitoring (TDM) of anti-TNF-α is an important tool in clinical practice for inflammatory diseases. In this study, we have evaluated the performance of several assays for drug and antidrug antibodies (ADA) measurement in the serum. 50 sera from patients treated with infliximab (IFX) and 49 sera from patients treated with adalimumab (ADAL) were monitored with four immunoassays. We have compared Promonitor, i-Track10^®, and ez-track1 assays to our gold standard Lisa Tracker^® ELISA using Cohen's kappa, Passing-Bablok, and Bland-Altman analysis. The qualitative analysis evaluated by Cohen's kappa values found for IFX measurements an "almost perfect" concordance for Promonitor, "moderate" for i-Track10^® and "substantial" for ez-Track1. For ADAL, kappa values were "moderate" for all tested methods. For anti-IFX, kappa values were "almost perfect" for Promonitor, "fair" for i-Track10^®, and "substantial" for ez-Track1. For anti-ADAL, kappa values were "almost perfect" for all three assays. For quantitative analysis of drug measurements, Pearson's r values were all above 0.9 and Lin's concordance coefficients of all immunoassays were around 0.80. Performances of the four evaluated immunoassays were acceptable for TDM based on our laboratory experience. Nevertheless, concordance between the four methods for IFX measurement was not perfect and we recommend the use of the same assay for the follow-up of a given patient. The performances of the four immunoassays evaluated were similar and are acceptable for TDM based on our laboratory experience.

Anti-Drug Antibodies in the Biological Therapy of Autoimmune Rheumatic Diseases

Autoimmune rheumatic diseases are a cluster of heterogeneous disorders that share some clinical symptoms such as pain, tissue damage, immune deregulation, and the presence of inflammatory mediators. Biologic disease-modifying antirheumatic drugs are some of the most effective treatments for rheumatic diseases. However, their molecular and pharmacological complexity makes them potentially immunogenic and capable of inducing the development of anti-drug antibodies. TNF inhibitors appear to be the main contributors to immunogenicity because they are widely used, especially in rheumatoid arthritis. Immunogenicity response on these treatments is crucial since the appearance of ADAs has consequences in terms of safety and efficacy. Therefore, this review proposes an overview of the immunogenicity of biological agents used in autoimmune rheumatic diseases highlighting the prevalence of anti-drug antibodies.

Validation Study of a New Random-Access Chemiluminescence Immunoassay Analyzer i-TRACK10® to Monitor Infliximab and Adalimumab Serum Trough Levels and Anti-Drug Antibodies

Background. Monitoring of biological TNF inhibitors is a very important tool to guide clinical decisions using specialized algorithms, especially in gastroenterology. A new chemiluminescent instrument (i-TRACK^10® from Theradiag) could replace ELISA techniques to calculate the dosage of drugs and anti-drug antibodies. In this bi-centric study, we explored the analytical performances of i-TRACK^10® using manual or automated (DS2^®) ELISA Lisa-Tracker^® assays, and compared the results. Patients and methods. Intra- and inter-run performances were evaluated with i-TRACK^10® in two different laboratories and for two different ranges of values for infliximab, adalimumab, and their respective antibodies. Patients’ samples were used in the labs to compare the results obtained between the new instrument and either the manual Lisa-Tracker^® or the automated DS2. Results. Intra- and inter-run performances were satisfactory, with values between 1.8% and 16.1% (for inter-run imprecision at low/medium values of infliximab). Results were generally comparable between assays. with the lowest value of correlation at 0.59 (anti-adalimumab dosage between i-TRACK^10® and manual ELISA). Most often, values of drugs and anti-drug antibodies were higher with i-TRACK^10® than with manual ELISA assay, and correlation values were better with automated ELISA. Agreements were globally acceptable, and the lowest coefficients of 0.7 was obtained for adalimumab values between i-TRACK^10® and the two ELISA methods, and for anti-adalimumab values between i-TRACK^10® and manual ELISA. The type of assay can potentially induce a change in the class of patients and lead to divergent therapeutic decisions. Conclusions. The new random-access instrument i-TRACK^10® presents many advantages in a routine laboratory: rapidity, the possibility of standardization, usability, and expansion of the measurement range. Despite the relatively good agreement of results, it is preferable to use the same assay in longitudinal follow-up of a patient, because quantitative results were not completely equivalent especially for anti-drug antibodies.

Therapeutic Drug Monitoring of Biologics in Crohn's Disease

Reactive therapeutic drug monitoring (TDM) is considered the standard of care for optimizing biologics in inflammatory bowel disease (IBD) including Crohn's disease (CD). Preliminary data show that proactive TDM is associated with positive outcomes in IBD and can be also used to efficiently guide therapeutic decisions in specific clinical scenarios. Higher biological drug concentrations are associated with favorable therapeutic outcomes in specific IBD populations or phenotypes including pediatric CD, perianal fistulizing CD, small bowel CD, and following an ileocolonic resection for CD. Future perspectives of TDM include the use of rapid testing, pharmacogenomics, and pharmacokinetic dashboards toward individualized therapy.

Optimizing therapeutic drug monitoring in inflammatory bowel disease: a focus on therapeutic monoclonal antibodies

INTRODUCTION

Therapeutic drug monitoring (TDM) is useful for optimizing monoclonal antibodies (mAbs) for the treatment of immune-mediated inflammatory disorders including inflammatory bowel disease (IBD). However, TDM in clinical practice is still restricted by long turnaround times between sampling and results and the fact that dosing of mAbs to a target drug concentration is challenging due to high pharmacokinetic (PK) variability at both a population and patient level. Overcoming these barriers may be addressed by point-of-care (POC) assays, model-informed precision dosing (MIPD), and pharmacogenetics/pharmacogenomics.

AREAS COVERED

This review provides an overview of the optimization of TDM of mAbs in IBD including POC testing, MIPD, and pharmacogenetics.

EXPERT OPINION

Recent advances in sampling, quantification, and support of clinical decisions include POC assays and PK dashboards, which may allow for prompt and precise application of TDM in clinical practice. Future perspectives toward a more personalized implementation of TDM could include the incorporation of pharmacogenetics/pharmacogenomics to identify subgroups of patients who would benefit more from proactive TDM or combination therapy such as those prone to immunogenicity and/or accelerated drug clearance. However, there are still challenges regarding the implementation of these innovative approaches, and more data from prospective studies and randomized controlled trials are needed.