Accuracy of the new rapid test for monitoring adalimumab levels

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.

Validation Study of Novel Point-of-Care Tests for Infliximab, Adalimumab and C-Reactive Protein in Capillary Blood and Calprotectin in Faeces in an Ambulatory Inflammatory Bowel Disease Care Setting

Background and aims: Point-of-care tests (POCT) allow instant measurement of inflammatory markers and drug concentrations. Here, we studied agreement between a novel POCT device and reference methods of measuring infliximab (IFX) and adalimumab (ADL) serum concentrations and C-reactive protein (CRP) and faecal calprotectin (FCP) concentrations of patients with inflammatory bowel disease (IBD). Methods: In this single-centre validation study, IBD patients were recruited in which IFX, ADL, CRP and/or FCP tests were required. IFX, ADL and CRP POCT were performed on capillary whole blood (CWB), obtained via finger prick. Additionally, IFX POCT was performed on serum samples. FCP POCT was performed on stool samples. Agreement between POCT and reference methods was tested using Passing-Bablok regression, intra-class correlation coefficients (ICC) and Bland-Altman plots. Results: In total, 285 patients participated. Passing-Bablok regression identified differences between the reference method and IFX CWB POCT (intercept = 1.56), IFX serum POCT (intercept = 0.71, slope = 1.10) and ADL CWB POCT (intercept = 1.44). There were also differences in the Passing-Bablok regressions of CRP (intercept = 0.81, slope = 0.78) and FCP (intercept = 51 and slope = 0.46). Bland-Altman plots demonstrated that IFX and ADL concentrations were slightly higher with the POCT and CRP and FCP were slightly lower with POCT. The ICC demonstrated almost perfect agreement with IFX CWB POCT (ICC = 0.85), IFX serum POCT (ICC = 0.96), ADL CWB POCT (ICC = 0.82) and CRP CWB POCT (ICC = 0.91) and moderate agreement with FCP POCT (ICC = 0.55). Conclusions: IFX and ADL results were slightly higher with this novel rapid and user-friendly POCT, whereas CRP and FCP results were slightly lower compared to the reference methods.

Adalimumab Serum Concentrations, Clinical and Endoscopic Disease Activity in Crohn's Disease: A Cross-Sectional Multicentric Latin American Study

Despite some variability in ideal serum Adalimumab (ADA) concentrations, there is increasing evidence that higher concentrations of anti-TNF-α agents can be associated with sustained efficacy, and low or undetectable levels may lead to loss of response. This study aims to correlate serum ADA concentrations with clinical and endoscopic activity in patients with Crohn's disease (CD). A cross-sectional and multicentric study was performed with patients with CD, who used ADA for at least 24 weeks. Patients were allocated into groups according to the presence of clinical or endoscopic disease activity. Serum ADA concentrations were measured and compared between groups. Overall, 89 patients were included. A total of 27 patients had clinically active CD and 62 were in clinical remission. Forty patients had endoscopic disease activity and 49 were in endoscopic remission. The mean serum ADA concentration was 10.2 μg/mL in patients with clinically active CD and 14.3 μg/mL in patients in clinical remission (p = 0.395). The mean serum ADA concentration in patients with endoscopic activity was 11.3 μg/mL as compared to 14.5 μg/mL in those with endoscopic remission (p = 0.566). There was no difference between serum ADA concentrations regarding clinical or endoscopic activity in CD, as compared to patients in remission.

Promising Tools to Facilitate the Implementation of TDM of Biologics in Clinical Practice

Therapeutic drug monitoring (TDM) of biologics—encompassing the measurement of (trough) concentrations and anti-drug antibodies—is emerging as a valuable tool for clinical decision making. While this strategy needs further validation, attention on its implementation into the clinic is warranted. Rapid testing and easy sampling are key to its implementation. Here, we aimed to evaluate the feasibility and volunteers’ perception of home microsampling for quantification of adalimumab (ADM) concentrations in psoriasis patients. In addition, we compared lateral flow testing (LFT) with enzyme-linked immunosorbent assay (ELISA). Patients participating in the SUPRA-A study (clinicaltrials.gov NCT04028713) were asked to participate in a substudy where volumetric absorptive microsampling (VAMS) was performed at home. At three time points, whole blood and corresponding serum samples were collected for ADM measurement using an in-house ELISA. In addition, the patients’ perspective on microsampling was evaluated via a questionnaire. LFT-obtained ADM concentrations agreed very well with ELISA results (Pearson’s correlation = 0.95 and R² = 0.89). ADM concentrations determined in both capillary (via finger prick) and corresponding venous blood VAMS samples correlated strongly with serum concentrations (Pearson’s correlation = 0.87). Our preliminary data (n = 7) on rapid testing and home-based microsampling are considered promising with regard to TDM implementation for adalimumab, warranting further research.

Next generation point-of-care test for therapeutic drug monitoring of adalimumab in patients diagnosed with autoimmune diseases

Therapeutic drug monitoring (TDM) of adalimumab (ADM) at the point-of-care (POC) is key to prevent loss of response but has not been accomplished to date because true POC testing solutions are still lacking. Here, we present a novel "whole blood in - result out" self-powered microfluidic chip for detecting ADM within 30 min to enable TDM at POC. Hereto, we first demonstrated on-chip plasma separation from whole blood, followed by downscaling an ADM ELISA with maintained specificity and sensitivity in plasma. This assay was then performed on a robust and easy-to-use microfluidic chip we designed based on (i)SIMPLE technology, allowing autonomous function upon single finger press activation, which was successfully validated with patient samples. Herein, we prove the potential of our technology to detect targets starting from whole blood introduced directly on-chip and to integrate various immunoassays, both for TDM and other in vitro diagnostics applications, like infectious diseases.

Adalimumab and anti-adalimumab LISA-TRACKER immunoassays performance criteria for therapeutic drug monitoring of adalimumab-amgen biosimilar (ABP501)

BACKGROUND

ABP501 is a biosimilar to Reference Adalimumab (HUMIRA®) produced by AMGEN. Adalimumab (ADA) has a marketing authorization for Crohn's disease, ulcerative colitis and other inflammatory or autoimmune diseases. The aim of this study was to evaluate the LISA-TRACKER assays developed by Theradiag (France), for the monitoring of ABP501 and anti-ABP501 antibodies in human serum.

RESULTS

68 ABP501 clinical samples were measured with the LISA TRACKER Duo Adalimumab assay. LISA TRACKER has been validated as suitable for quantification of ABP501 in human serum samples. Accuracy of the LISA-TRACKER was measured using 3 human serum matrices spiked with known levels of biosimilar, 3 levels spanning the dynamic range. Percentages of recovery were ranged from 90 to 120% for biosimilar batch1, and between 93 and 105% for biosimilar batch2. The acceptance criteria (CV < 20%) were met for intra-run (from 3.8 to 16.5%) and inter-run imprecision (from 4.4 to 13.9%) including the two batches. All results were comprised within ± 20% from results, obtained with the kit and sample unexposed in order to evaluate stability of the sample, stability of the kit and consistency of the results. In any case, but two, all percentages of inhibition were > 50% for specificity. Specificity was tested with Biosimilar spiked samples, Biosimilar with Humira® spiked samples, and clinical samples from patients treated with adalimumab biosimilar. All of these samples were spiked with polyclonal antibodies directed against Humira®. Specificity inhibition and specificity detection steps were also part of the validation parameters. Reagents made with ABP501 gave similar results than reagents made with Humira® meeting acceptance criteria.

CONCLUSIONS

LISA-TRACKER ADA and anti-ADA assays are reliable for the monitoring of patients treated with ABP501.

The First WHO International Standard for Adalimumab: Dual Role in Bioactivity and Therapeutic Drug Monitoring

The expanded availability of adalimumab products continues to widen patient access and reduce costs with substantial benefit to healthcare systems. However, the long-term success of these medicines is highly dependent on maintaining consistency in quality, safety and efficacy while minimizing any risk of divergence during life-cycle management. In recognition of this need and demand from global manufacturers, the World Health Organization (WHO) Expert Committee on Biological standardization established the WHO 1^st International standard (IS) for Adalimumab (coded 17/236) in October 2019 with a defined unitage ascribed to each of the individual bioactivities evaluated in the study namely, TNF-α binding, TNF-α neutralization, complement dependent cytotoxicity and antibody-dependent cellular cytotoxicity. For development of the IS, two candidate standards were manufactured as per WHO recommendations. Analysis of extensive datasets generated by testing of a common set of samples including the candidate standards by multiple stakeholders including regulatory agencies using their own qualified assays in a large international collaborative study showed comparable biological activity for the tested candidates for the different activities. Use of a common standard significantly decreased the variability of bioassays and improved agreement in potency estimates. Data from this study clearly supports the utility of the IS as an important tool for assuring analytical assay performance, for bioassay calibration and validation, for identifying and controlling changes in bioactivity during life-cycle management and for global harmonization of adalimumab products. In addition, in a separate multi-center study which included involvement of hospital and clinical diagnostic laboratories, the suitability of the adalimumab IS for therapeutic drug monitoring assays was examined by analysis of data from testing of a common blind coded panel of adalimumab spiked serum samples representative of the clinical scenario along with the IS and in-house standards in diverse immunoassays/platforms. Both commercially available and in-house assays that are routinely used for assessing adalimumab trough levels were included. Excellent agreement in estimates for adalimumab content in the spiked samples was observed regardless of the standard or the method with inter-laboratory variability also similar regardless of the standard employed. This data, for the first time, provides support for the extended applicability of the IS in assays in use for therapeutic drug monitoring based on the mass content of the IS. The adalimumab IS, in fulfilling clinical demand, can help toward standardizing and harmonizing clinical monitoring assays for informed clinical decisions and/or personalized treatment strategies for better patient outcomes. Collectively, a significant role for the adalimumab IS in assuring the quality, safety and efficacy of adalimumab products globally is envisaged.

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

BACKGROUND

Adalimumab (ADL), infliximab (IFX) and their biosimilars are widely used biological drugs. Some patients, however, generate neutralizing antibodies that hamper the effectiveness of these drugs. Evidence shows therapeutic drug monitoring of serum levels ADL/IFX and anti-drug antibodies (ADA) is useful to improve treatment effectiveness. We evaluated a new rapid quantitative method, Quantum Blue (QB), for determining serum anti-ADL and anti-IFX antibodies (Research Use Only labelling) by comparing it with two established ELISA kits, Promonitor (PM) and Lisa-Tracker (LT).

METHODS

Eighty samples (40 for each drug type) were analysed. Percentage of agreement and kappa statistic were used to compare positive/negative ADA results. Clinical implications for drug treatment in the patients with discordant results were evaluated. The Chi-square test was used to analyze differences for ADA detection in patients with disease flare and without concomitant immunosuppressant treatment.

RESULTS

Agreement exceeded 80 % among anti-ADL methods. Although LT ELISA showed a lower capacity in detecting anti-ADL antibodies, discrepancies were found for levels close to the cut-off concentration, thus having minimal impact on clinical decisions. Conversely, QB anti-IFX displayed low agreement with PM and LT ELISA kits (67.5 % and 50 %, respectively), and was unable to detect high levels of antibodies, therefore having major clinical implications. Agreement between PM and LT ELISA anti-IFX kits was 82.5 % with all discordant results being undetected for PM and slightly positive for LT.

CONCLUSION

QB anti-ADL shows similar performance to ELISA kits while QB anti-IFX needs further improvements to achieve reliable antibody detection.

Evaluation of two point of care technologies for measuring monoclonal antibody therapeutic-A concentrations in blood

Aim: Current blood monitoring methods require sample collection and testing at a central lab, which can take days. Point of care (POC) devices with quick turnaround time can provide an alternative with faster results, allowing for real-time data leading to better treatment decisions for patients. Results/Methodology: An assay to measure monoclonal antibody therapeutic-A was developed on two POC devices. Data generated using 75 serum samples (65 clinical & ten spiked samples) show correlative results to the data generated using Gyrolab technology. Conclusion: This case study uses a monoclonal antibody therapeutic-A concentration assay as an example to demonstrate the potential of POC technologies as a viable alternative to central lab testing with quick results allowing for real-time decision-making.