Detection of adalimumab and anti-adalimumab antibodies in patients with rheumatoid arthritis: a comprehensive overview of methodology pitfalls and benefits

Real-World Implementation and Outcomes of Adalimumab Therapeutic Drug Monitoring in Psoriasis: A National Specialized Center Experience

Serum adalimumab concentration is a biomarker of treatment response but therapeutic drug monitoring (TDM) is yet to be implemented in routine psoriasis care. We incorporated adalimumab TDM in a national specialized psoriasis service and evaluated it using the RE-AIM (Reach, Effectiveness, Adoption, Implementation, and Maintenance) implementation science framework. We undertook pre-implementation planning (validating local assays) and implementation interventions targeted to patients (pragmatic sampling at routine reviews), clinicians (introduction of a TDM protocol), and healthcare systems (adalimumab TDM as a key performance indicator). Over 5 months, 170 of 229 (74%) individuals treated with adalimumab received TDM. Clinical improvement after TDM-guided dose escalation occurred in 13 of 15 (87%) nonresponders with serum drug concentrations <8.3 μg/ml (median PASI reduction of 3.2 [interquartile range = 2.2-8.2] after 23.4 weeks) and in all nonresponders who had TDM-guided switch in biologic due to supratherapeutic drug concentrations (>8.3 μg/ml; n = 2) or positive antidrug antibody (n = 2) (PASI reduction of 7.8 [interquartile range = 7.5-12.9] after 20.0 weeks). Proactive TDM led to dose reduction in five individuals with clear skin and subtherapeutic or supratherapeutic drug concentrations; four (80%) sustained clear skin after 50 weeks (range = 42-52). Adalimumab TDM based on pragmatic serum sampling is clinically viable and may lead to patient benefit. Context-specific implementation interventions and systematic implementation assessment may bridge the biomarker research-to-practice gap.

Pharmacological strategies for mitigating anti-TNF biologic immunogenicity in rheumatoid arthritis patients

Tumor necrosis factor alpha (TNFα) inhibitors are a mainstay of treatment for rheumatoid arthritis (RA) patients after failed responses to conventional disease-modifying antirheumatic drugs (DMARDs). Despite the clinical efficacy of TNFα inhibitors (TNFi), many RA patients experience TNFi treatment failure due to the development of anti-drug antibodies (ADAs) that can neutralize drug levels and lead to RA disease relapse. Methotrexate (MTX) therapy with concomitant TNFα inhibitors decreases the risk of TNFi immunogenicity, but additional and/or alternative strategies are needed to reduce MTX-associated toxicities and to further increase its potency for preventing TNFα inhibitor immunogenicity. In this review, we highlight the limitations of MTX for mitigating TNFα inhibitor immunogenicity, and we discuss potential alternative pharmacological targets for decreasing the risk of immunogenicity during TNFα inhibitor therapy based on the key kinases, second messengers, and shared signaling mechanisms of lymphocyte receptor signaling.

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-tumor 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 titers 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 infliximab (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 as IFX or ADM concentration is typically high.

Anti-TNFα drug levels in patients with rheumatoid arthritis and spondyloarthritis

BACKGROUND AND OBJECTIVES

Knowledge of the levels of anti-TNFa drugs can modify treatment in patients with rheumatoid arthritis (RA) and spondyloarthritis (SpA).

OBJECTIVES

To compare the levels of anti-TNFa in patients with RA vs SpA, in different clinical situations.

MATERIALS AND METHODS

A retrospective, observational study was conducted. Levels of anti-TNFa and the presence of anti-drug antibodies were measured in consecutively selected patients, using the ELISA technique.

RESULTS

Fifty-three, 73 and 78 patients treated with infliximab, adalimumab and etanercept were studied, respectively. The median drug levels in patients using standard doses were infliximab 2.2 µg/mL (1.4-5.2), adalimumab 4.9 µg/mL (0.8-8.9) and etanercept 3.1 µg/mL (2.3-4.4). There were no differences in drug levels according to disease activity but we found differences in etanercept and infliximab levels according to DMARD use.

CONCLUSIONS

Levels of anti-TNFa drugs will change with DMARD treatment.

Immunogenicity of Monoclonal Antibodies and the Potential Use of HLA Haplotypes to Predict Vulnerable Patients

The use of monoclonal antibodies (mAbs) in the clinic has successfully expanded to treatment of cancer, viral infections, inflammations, and other indications. However, some of the classes of mAbs that are used in the clinic show the formation of anti-drug antibodies (ADAs) leading to loss of efficacy. This review describes ADA formation for the various mAbs, and its clinical effect. Lastly, this review considers the use of HLA-haplotypes as biomarkers to predict vulnerability of patients sensitive to formation of ADAs.

Accelerated Discovery of Potent Bioactive anti-TNFα Aptamers by Microbead-Assisted Capillary Electrophoresis (MACE)-SELEX

Dysregulation of tumor necrosis factor-α (TNFα), a pro-inflammatory cytokine, causes several diseases, making it an important therapeutic target. Here, we identified a novel DNA aptamer against human TNFα using in vitro selection, which included a high exclusion pressure process against non-binding and weak binders through microbead-assisted capillary electrophoresis (MACE) in only three rounds. Among the 15 most enriched aptamers, Apt14 exhibited the highest inhibitory activity for the interaction between TNFα and its cognate receptor in mouse L929 cells. For further improving the bioactivity of the aptamer, dimerization programed by hybridization was evaluated, resulting in the Apt14 dimer exhibited a twofold higher binding affinity and stronger inhibition compared to the monomer counterpart. Rapid identification of bioactive aptamers using MACE in combination with facile dimerization by hybridization accelerates the discovery of novel bioactive aptamers, paving the way toward replacing current monoclonal antibody therapy with the less expensive and non-immunogenic aptamer therapy.

Anti-TNFα Drug Levels in Patients with Rheumatoid Arthritis and Spondyloarthritis

BACKGROUND AND OBJECTIVES

Knowledge of the levels of anti-TNFα drugs can modify treatment in patients with rheumatoid arthritis (RA) and spondyloarthritis (SpA).

OBJECTIVES

To compare the levels of anti-TNFα in patients with RA vs SpA, in different clinical situations.

MATERIALS AND METHODS

A retrospective, observational study was conducted. Levels of anti-TNFα and the presence of anti-drug antibodies were measured in consecutively selected patients, using the ELISA technique.

RESULTS

Fifty-three, 73 and 78 patients treated with infliximab, adalimumab and etanercept were studied, respectively. The median drug levels in patients using standard doses were infliximab 2.2μg/ml (1.4-5.2), adalimumab 4.9μg/ml (0.8-8.9) and etanercept 3.1μg/ml (2.3-4.4). There were no differences in drug levels according to disease activity but we found differences in etanercept and infliximab levels according to DMARD use.

CONCLUSIONS

Levels of anti-TNFα drugs will change with DMARD treatment.

A pilot clinical study of the therapeutic antibody against canine PD-1 for advanced spontaneous cancers in dogs

Inhibition of programmed death 1 (PD-1), expressed on activated T cells, can break through immune resistance and elicit durable responses in human melanoma as well as other types of cancers. Canine oral malignant melanoma is one of the most aggressive tumors bearing poor prognosis due to its high metastatic potency. However, there are few effective treatments for the advanced stages of melanoma in veterinary medicine. Only one previous study indicated the potential of the immune checkpoint inhibitor, anti-canine PD-L1 therapeutic antibody in dogs, and no anti-canine PD-1 therapeutic antibodies are currently available. Here, we developed two therapeutic antibodies, rat-dog chimeric and caninized anti-canine PD-1 monoclonal antibodies and evaluated in vitro functionality for these antibodies. Moreover, we conducted a pilot study to determine their safety profiles and clinical efficacy in spontaneously occurring canine cancers. In conclusion, the anti-canine PD-1 monoclonal antibody was relatively safe and effective in dogs with advanced oral malignant melanoma and other cancers. Thus, our study suggests that PD-1 blockade may be an attractive treatment option in canine cancers.

Adalimumab Immunogenicity Is Negatively Correlated with Anti-Hinge Antibody Levels in Patients with Rheumatoid Arthritis

Patients with rheumatoid arthritis (RA) are frequently treated with anti-tumor necrosis factor-α immunoglobulin therapy but develop neutralizing antibodies against these drugs, necessitating therapeutic monitoring of drug concentrations and anti-drug antibodies. Patients with RA have multiple factors related to their autoimmune disposition that interfere with conventionally used methods to detect anti-drug antibodies. Currently deployed analytical methods have significant limitations that hinder clinical interpretation and/or routine use, and no method can detect immunogenicity and drug levels simultaneously to provide clinically meaningful recommendations. Given these limitations, the objective of this study was to identify sources of and associations with assay interference in patients with RA. We designed a modular immunogenicity and drug concentration detection technology to identify the factors that interfere with the detection of adalimumab and anti-adalimumab antibodies in a cohort of 206 patients with RA. Patients were included from the University of Pittsburgh Rheumatoid Arthritis Comparative Effectiveness Research registry. In this cohort, we analyzed clinical and plasma factors associated with anti-adalimumab and anti-hinge antibodies. A novel flow cytometry-based assay was developed and validated that simultaneously measures adalimumab and anti-adalimumab antibody concentrations, overcoming many of the interference factors that are limitations of conventional assays, including anti-fragment crystallizable (Fc) and anti-hinge antibodies. C-reactive protein (P = 0.035), Disease Activity Score-28 (DAS28) score (P = 0.002), and disease activity category (P = 0.009) were significantly associated with anti-adalimumab antibodies but not with anti-hinge antibodies (P > 0.05). Anti-hinge antibodies were inversely associated with drug-neutralizing antibodies (P = 0.002). In patients with RA, anti-hinge antibodies may have a potential protective effect against the development of anti-adalimumab antibodies. SIGNIFICANCE STATEMENT: Using a novel cytometric assay that simultaneously measures drug and anti-drug antibodies, we overcame many interferences that hinder the clinical interpretation of adalimumab immunogenicity testing. Our investigation in patients with RA demonstrated that immunogenicity impaired the pharmacological action of adalimumab via analysis of RA disease severity markers. We also demonstrate that patients with anti-hinge antibodies had lower anti-adalimumab antibody levels and decreased drug neutralization. Our results suggest that anti-hinge antibodies can predict adalimumab immunogenicity before the start of therapy.

Point-of-Care Assays Could Be Useful for Therapeutic Drug Monitoring of IBD Patients in a Proactive Strategy with Adalimumab

The objective of the study was to evaluate whether Point-of-Care (POC) assays are equivalent to ELISAs for measuring residual trough levels of adalimumab (ADA) in a cohort of Inflammatory Bowel Disease (IBD) patients. ADA trough levels obtained by POC assays were used to optimize patients in daily clinical practice. Different assays (three ELISAs (Enzyme-Linked ImmunoSorbent Assay) from two different suppliers and two POC assays) were compared to measure ADA trough levels in a first cohort of 31 IBD patients. All assays revealed a high correlation within the assays, ranging from 0.86 to 0.99. Cut-off values were always higher with ELISAs than with POC assays. Then, a small prospective clinical study with a second cohort of 37 IBD patients was performed to compare POC assays and ELISAs for their ability to optimize patients on the basis of the measured ADA trough levels. The use of a POC assay to monitor ADA trough levels did not improve the follow-up of patients with loss of response, as they were always optimized whatever their ADA residual rate. For patients in clinical remission, a POC assay can be useful in some clinical situations to maintain or de-escalate ADA doses according to the measured trough levels. In conclusion, different assays for ADA monitoring are quite equivalent. A POC assay could be only useful for a proactive strategy for asymptomatic patients with a sub-therapeutic dose of ADA, but new therapeutic thresholds need to be identified.

Routinely utilized in-house assays for infliximab, adalimumab and their anti-drug antibody levels

By monitoring serum concentrations of infliximab (IFX) and adalimumab (ADL) and levels of their antibodies in patients with inflammatory diseases, clinicians can adjust dose and increase safety and effectiveness of treatment. The aim was to develop and validate in-house enzyme-linked immunosorbent assays (ELISAs) for IFX and ADL, together with anti-IFX and anti-ADL ELISAs for routine detection and further analysis with acid dissociation of immune complexes. Furthermore, the objectives were to compare in-house assays with commercial ELISAs and reporter gene assays (RGAs) and to determine cross-reactivity between original Remicade®/Remsima™ and their antibodies. In-house ELISAs were validated (imprecision, accuracy among other criteria) and compared with commercial apDia ELISAs and RGAs. Correlation coefficients, intraclass correlation coefficients, agreement, and bias were calculated. All in-house ELISAs gave precise and repeatable results. The immune complexes between IFX and anti-IFX were found in 3% of samples, while complexes between ADL and anti-ADL were found in 14% of samples. Significant correlations were found between in-house and apDia ELISAs and RGA for IFX, ADL, anti-IFX, and anti-ADL results. Remicade®, Remsima™, and their antibodies could be accurately measured with either apDia or in-house IFX and anti-IFX ELISAs. Accurate and precise in-house ELISAs, highly comparable with commercial ELISAs and RGAs, were developed and validated for routine analysis of samples of patients treated with IFX (Remicade® or Remsima™) or ADL providing substantial cost benefit. Complex dissociation identified samples with anti-IFX-IFX (3%) and anti-ADL-ADL (14%) complexes indicating the benefit of adding acid dissociation to therapeutic drug monitoring of IFX and ADL.

Comparison of a new rapid method for the determination of adalimumab serum levels with two established ELISA kits

Background

Therapeutic drug monitoring (TDM) of adalimumab (ADA) in inflammatory bowel diseases (IBDs) has gained increased attention since several studies showed a correlation between drug levels and mucosal healing. The limitations of routine usage of enzyme-linked immunoabsorbent assay (ELISA) kits for measuring serum ADA concentrations have prompted the development of rapid methods, such as Quantum Blue (QB). We evaluated the interchangeability and agreement between the QB method and two established ELISA kits, Promonitor (PM) and Lisa-Tracker (LT).

Methods

Fifty samples from patients with IBD were included. Quantitative analysis was performed using the ANOVA test for repeated measures, Deming regression and the Bland-Altman plot. Clinical implications were evaluated by concordance in classifying patients into therapeutic windows according to the proposed cut-off levels for subtherapeutic (either <5 or <7.5 μg/mL) and supratherapeutic (>12 μg/mL) ranges.

Results

Statistical differences were detected between the QB method and the two ELISA kits, with QB overestimating ADA serum values compared to them. A lack of interchangeability was observed between methods, with greater differences as ADA levels increased. An analysis of a sub-set of samples with ADA values below 9 μg/mL (n = 25) showed that QB fulfilled the criteria to be interchangeable with the LT assay. Concordance for patient classification into ADA therapeutic windows was better for QB vs. LT than for QB vs. PM, with high agreement (>75%) for subtherapeutic levels among the three methods.

Conclusions

Although quantitative differences existed between the rapid method and ELISA kits that hampered their interchangeability, the agreement for identifying patients with subtherapeutic values of ADA was high.