Belatacept (Nulojix; Bristol-Myers Squibb, New York, NY) is a biological immunosuppressive drug used for the prophylaxis of acute rejection after renal transplantation. Few studies have described belatacept pharmacokinetics, and the effect of therapeutic drug monitoring has not been investigated. We have developed a drug-capture assay (using drug target) to measure belatacept in serum and applied this assay in a pharmacokinetic study in renal transplant recipients.CD80 was used to trap belatacept onto streptavidin-coated wells. Captured drug was quantified using Eu-labeled protein A and time-resolved fluorescence. The assay was applied in a pilot pharmacokinetic study in renal transplanted patients receiving belatacept infusions. Belatacept serum concentrations were determined at several time points between belatacept infusions. A simple population pharmacokinetic model was developed to visualize measured and predicted belatacept serum concentrations.The assay range was 0.9-30 mg/L with accuracy within 91%-99% and coefficients of variation ranging from 1.2% to 3.6%. Predilution extended the measurement range to 130 mg/L with an accuracy of 90% and coefficients of variation of 3.8%. Samples were stable during storage at 4°C for 15 days and during 2 freeze-thaw cycles. Belatacept concentrations were determined in a total of 203 serum samples collected during 26 infusion intervals from 5 renal transplant recipients. The population pharmacokinetic model visualized both measured and predicted concentrations.We have developed an automated, accurate, and precise assay for the determination of belatacept serum concentrations. The assay was successfully applied in a pharmacokinetic study in renal transplant recipients receiving belatacept infusions.
Background: Immunoassays are used to measure a range of analytes in clinical laboratories. Rheumatoid factor (RF) and other patient antibodies, such as heterophilic antibodies, can bind animal antibodies used in immunoassays and cause erroneous results, which may lead to misdiagnosis and incorrect treatment of patients. 1 Objectives: To assess RF reactivity to animal antibodies and to test if selected commercial immunoassays are vulnerable to interference from RF-positive sera. Methods: Samples from 124 patients with RF-positive rheumatoid arthritis (RA) included in the Norwegian Very Early Arthritis Clinic (NOR-VEAC)-cohort 2 were included in the study. Samples from patients with seronegative RA (n=51) and psoriatic arthritis (n=15) from the same cohort were included as controls. Reactivity to mouse IgG1, mouse IgG2a, rabbit IgG, bovine IgG, sheep/goat IgG and human IgG was analysed using in-house interference assays detecting antibodies able to cross-link the animal or human antibodies. RF-positive sera with strong reactivity to mouse IgG1 were selected for testing in three commercial immunoassays previously shown to be susceptible to interference from heterophilic antibodies; Abbott Architect Total β-hCG assay, BioRad 27-plex cytokine assays and Roche Elecsys Soluble Transferrin Receptor (sTfR). 3 Samples were tested before and after addition of blocking aggregated murine IgG1 (interference protection). Interference was defined as a discrepancy between the unblocked and blocked samples likely to influence clinical interpretation of the results and exceeding the reported assay imprecision with a considerable margin. Results: We found considerably stronger reactivity toward animal antibodies, particularly mouse IgG1 and rabbit IgG, in sera from RF-positive RA-patients compared to the control group (Fig. 1a-b). In the Abbott β-hCG assay, interference was shown in 6 out of the 30 tested sera (Fig. 2a). In the 27-plex cytokine assays, interference was demonstrated in 7 out of 10 tested sera (for 3-14 analytes). Furthermore, 17 out of the 27 cytokine assays were found to be susceptible to interference (Fig. 2b). Interference was shown in 2 out of 33 samples in the sTfR assay. In unblocked samples, sTfR values were 8.1 and 8.2 mg/L, vs. 4.2 mg/L and 6.0 mg/L in blocked samples, respectively. Additionally, 3 sera had >25% relative difference, but the results were within the reference range. Figure. 1 (a-b) Figure. 2 (a-b) Conclusion: Reactivity to animal antibodies used in immunoassays is common in sera from RF-positive RA patients and are associated with falsely elevated results in commercial immunoassays. In our cohort, interference was demonstrated in a considerable proportion of samples in the Abbott hCG and 27-plex cytokine assays. Physicians as well as researchers, laboratories and assay manufacturers must be alert to the risk of falsely elevated test results in RF positive RA patients, particularly when results are unexpected or discordant with clinical findings. False test results may interfere with research results, and also lead to potentially harmful diagnostic and therapeutic interventions if unrecognised. References: [1] Bolstad N, et al. Heterophilic antibody interference in immunometric assays. Best Pract Res Clin Endocrinol Metab 2013;27(5):647-61. [2] Norli ES, et al. Diagnostic spectrum and 2-year outcome in a cohort of patients with very early arthritis. RMD Open 2017;3(2):e000573. [3] Bolstad N, et al. Heterophilic antibody interference in commercial immunoassays; a screening study using paired native and pre-blocked sera. Clinical Chem Lab Med 2011;49(12):2001-6. Disclosure of Interests: Johanna Elin Gehin Speakers bureau: Roche, Rolf Anton Klaasen: None declared, Ellen Sauar Norli: None declared, Silje Watterdal Syversen Speakers bureau: Roche, Thermo Fisher, Guro Løvik Goll Consultant of: Novartis, Pfizer, Speakers bureau: Abbvie, Biogen, Boehringer Ingelheim, Orion Pharma, Eli Lilly, Novartis, Pfizer, MSD, Roche, UCB, David J Warren: None declared, Tore K. Kvien Grant/research support from: Received grants from Abbvie, Hospira/Pfizer, MSD and Roche (not relevant for this abstract)., Consultant of: Have received personal fees from Abbvie, Biogen, BMS, Celltrion, Eli Lily, Hospira/Pfizer, MSD, Novartis, Orion Pharma, Roche, Sandoz, UCB, Sanofi and Mylan (not relevant for this abstract)., Paid instructor for: Have received personal fees from Abbvie, Biogen, BMS, Celltrion, Eli Lily, Hospira/Pfizer, MSD, Novartis, Orion Pharma, Roche, Sandoz, UCB, Sanofi and Mylan (not relevant for this abstract)., Speakers bureau: Have received personal fees from Abbvie, Biogen, BMS, Celltrion, Eli Lily, Hospira/Pfizer, MSD, Novartis, Orion Pharma, Roche, Sandoz, UCB, Sanofi and Mylan (not relevant for this abstract)., Kjell Johannes Nustad: None declared, Maria D Mjaavatten Speakers bureau: Pfizer, Abbott, Nils Bolstad Consultant of: Pfizer, Janssen, Speakers bureau: Orion Pharma, Napp Pharmaceuticals, Takeda, Roche, Novartis
To explore the effects of anti-tumour necrosis factor (TNF)alpha antibody therapy on bone mineral density (BMD) of the lumbar spine and femur neck in patients with rheumatoid arthritis (RA).A total of 50 patients with active RA (DAS28> or =3.2) who started adalimumab (40 mg subcutaneously/2 weeks) were included in an open label prospective study. All patients used stable methotrexate and were allowed to use prednisone (< or =10 mg/day). The BMD of the lumbar spine and femur neck was measured before and 1 year after start of treatment.Disease activity at baseline (28-joint Disease Activity Score (DAS28)) and disease duration were inversely correlated with femoral neck BMD and lumbar spine BMD (p<0.05). Mean BMD of lumbar spine and femur neck remained unchanged after 1 year of adalimumab therapy (+0.3% and +0.3%, respectively). Of interest, a beneficial effect of prednisone on change in femur neck BMD was observed with a relative increase with prednisone use (+2.5%) compared to no concomitant prednisone use (-0.7%), (p = 0.015).In contrast to the progressive bone loss observed after conventional disease-modifying antirheumatic drug therapy, TNF blockade may result in an arrest of general bone loss. Consistent with previous observations, the data also suggest that the net effect of low-dose corticosteroids on BMD in RA may be beneficial, possibly resulting from their anti-inflammatory effects.
Background: TNF-alpha inhibitors have improved treatment of chronic immune-mediated inflammatory disorders. The NOR-SWITCH main and extension trial addressed switching from infliximab originator (IFX) to CT-P13 across six diseases. Here we present the exploratory post-hoc analyses in Crohn's disease (CD) and ulcerative colitis (UC).Methods: The 52-week, randomized, non-inferiority, double blind, multicenter, phase 4 NOR-SWITCH study was followed by a 26-week open extension trial where all patients received treatment with CT-P13. Treatment efficacy, safety and immunogenicity were assessed throughout the 78-week study period. The primary endpoint was disease worsening.Findings: The main and extension trials included 155 and 93 patients with CD and 93 and 80 patients with UC, respectively. The baseline characteristics were comparable between treatment arms in both diseases. Disease worsening in the main trial occurred in 14 (21%) of CD patients in the IFX group and 23 (37%) in the CT-P13 group (risk difference -14⋅3%, CI -29⋅3 to 0⋅7). In the extension study, disease worsening occurred in 13 (21%) patients in the CT-P13 maintenance group and 8 (13%) in the IFX/CT-P13 switch group (risk difference 7⋅9%, CI -5⋅2 to 21). The corresponding results in UC were 3 (9%) and 5 (12%) patients (risk difference -2⋅6%, CI -15⋅2 to 10⋅0) in the main trial, and 6 (15%) and 1 (3%) patients (risk difference 12⋅4%, CI -0⋅1 to 25⋅0) in the extension trial. In both diseases, the treatment groups were similar across disease activity measures, drug levels and immunogenicity.Interpretation: The subgroup analyses of IBD in the NOR-SWITCH main and extension trials support switching from originator infliximab to CT-P13 for non-medical reasons.Trial Registration: ClinicalTrials.gov NCT-02148640, EudraCT Number: 2014-002056-40.Funding Statement: This work was supported by the Norwegian Ministry of Health and Care Services.Declaration of Interests: KKJ reports personal fees from Intercept, Norgine and Celltrion. GLG reports personal fees from AbbVie, Biogen, Eli Lilly, MSD, Novartis, Pfizer, Roche, Sandoz, Orion Pharma, Celltrion and Boehringer Ingelheim. NB reports personal fees received from Orion Pharma, Roche, Napp Pharmaceuticals, Pfizer, and Takeda. ICO reports grants from Norwegian Ministry of Health and Care Services during the conduct of the study, and personal fees from Pfizer. EAH reports grants from AbbVie, Pfizer, UCB, Roche, and MSD. IPB reports personal fees from AbbVie, MSD, Takeda, Hospira, and Ferring. KEAL reports grants from MSD, personal fees from Takeda, Orion, Abbvie, Pfizer, and MSD. JJ reports personal fees from MSD, AbbVie, Celltrion, Orion Pharma, Takeda, Napp Pharm, AstroPharma, Hikma and Pfizer. TKK reports reports grants from Norwegian Ministry of Health and Care Services during the conduct of the study and personal fees from AbbVie, Biogen, BMS, Boehringer Ingelheim, Celltrion, Eli Lilly, Epirus, Janssen, Merck-Serono, MSD, Mundipharma, Novartis, Oktal, Orion Pharma, Hospira/Pfizer, Roche, Sandoz, and UCB Pharma. SOF reports personal fees from Takeda, Pharmacosmos, Tillotts, Janssen, Intercept and Pfizer.Ethics Approval Statement: The study was conducted in compliance with the Declaration of Helsinki and the International Conference on Harmonization Guidelines for Good Clinical Practice. The study protocol and consent documents were approved by an independent ethics committee (Regional Committees for Medical and Health Research Ethics South East; reference number 2014/848), by appropriate institutional review boards and by the Norwegian Medicines Agency (reference number 14/07192-11).
Abstract Background Immunogenicity is a leading cause of treatment failure to TNF inhibitors. Genetic variations in HLA class II genes have been suggested to predispose to anti-drug antibody formation, but studies using high-resolution HLA typing as well as characterisation of biologically relevant haplotypes are currently lacking. The aim of this study was to assess associations between HLA loci and immunogenicity to infliximab. Methods Patients with immune-mediated inflammatory diseases (IMID) treated with infliximab (N=612) (120 rheumatoid arthritis, 181 spondyloarthritis, 72 psoriatic arthritis, 114 ulcerative colitis, 80 Crohn disease, and 45 psoriasis) were included in the randomised, Norwegian Drug Monitoring (NOR-DRUM) trial. Neutralising anti-drug antibodies were detected with an automated fluorescence assay. Next generation HLA sequencing at G group resolution were performed and trimmed to 2nd field. Haplotype analyses including the most significant HLA loci were performed, and epitope predictions for the infliximab light- and heavy-chain were assessed. Results Anti-drug antibodies to infliximab were detected in 147 (24 %) of patients. The most significant associations with immunogenicity were with the genes HLA-DQB1 (P=1.4x10-6), -DRB1 (P= 2.7x10-5), -DQA1 (P=0.00017) and -B (P=0.0009). Conditional analyses indicated that HLA-DQB1 represents the primary association(Table 1). Haplotype analyses showed that there was significantly increased risk of immnogenicity in patients carrying the HLA-DQ2 haplotypes DQB1*02:01~DQA1*05:01 (P=1.1x10-6) and DQB1*02:02~DQA1*02:01 (P=0.008), while one protective haplotype DQB1*05:01~DQA1*01:01 (P=0.0005) was identified (Figure 1a-c). Presence of HLA-DQ2 more than doubled the risk of anti-drug antibody formation (HR 2.54, 95%CI 1.82–3.56) (Figure 1d), in a model including the covariates age, sex, diagnosis, and concomitant immunosuppressive therapy. Association tests of each level of HLA analyses showed that HLA-DQ2 represents the strongest association(Figure 2). Epitope predictions revealed that the HLA-DQ2 haplotypes DQB1*02:01-DQA1*05:01 and DQB1*02:02-DQA1*02:01 share nine strong binder peptides, originating from the infliximab light chain, encompassing the amino acid core-peptide sequences INTVESEDI and VYACEVTHQ. Conclusion Using high-resolution HLA sequencing, we here demonstrate a genetic association between HLA-DQ2 and infliximab immunogenicity in IMID patients. The presence of either HLA-DQ2 risk haplotypes more than doubled the risk of anti-drug antibody formation across all diagnoses. Testing for HLA-DQ2 could be of clinical value in identifying patients at risk for immunogenicity and facilitate treatment decisions. Whether these findings apply to other TNF inhibitors should be further explored.
Proactive therapeutic drug monitoring (TDM), defined as individualized drug dosing based on scheduled monitoring of serum drug levels, has been proposed as an alternative to standard therapy to maximize efficacy and safety of infliximab and other biological drugs. However, whether proactive TDM improves clinical outcomes when implemented at the time of drug initiation, compared with standard therapy, remains unclear.
Objective
To assess whether TDM during initiation of infliximab therapy improves treatment efficacy compared with standard infliximab therapy without TDM.
Design, Setting, and Participants
Randomized, parallel-group, open-label clinical trial of 411 adults with rheumatoid arthritis, spondyloarthritis, psoriatic arthritis, ulcerative colitis, Crohn disease, or psoriasis initiating infliximab therapy in 21 hospitals in Norway. Patients were recruited from March 1, 2017, to January 10, 2019. Final follow-up occurred on November 5, 2019.
Interventions
Patients were randomized 1:1 to receive proactive TDM with dose and interval adjustments based on scheduled monitoring of serum drug levels and antidrug antibodies (TDM group; n = 207) or standard infliximab therapy without drug and antibody level monitoring (standard therapy group; n = 204).
Main Outcomes and Measures
The primary end point was clinical remission at week 30.
Results
Among 411 randomized patients (mean age, 44.7 [SD, 14.9] years; 209 women [51%]), 398 (198 in the TDM group and 200 in the standard therapy group) received their randomized intervention and were included in the full analysis set. Clinical remission at week 30 was achieved in 100 (50.5%) of 198 and 106 (53.0%) of 200 patients in the TDM and standard therapy groups, respectively (adjusted difference, 1.5%; 95% CI, −8.2% to 11.1%;P = .78). Adverse events were reported in 135 patients (68%) and 139 patients (70%) in the TDM and standard therapy groups, respectively.
Conclusions and Relevance
Among patients with immune-mediated inflammatory diseases initiating treatment with infliximab, proactive therapeutic drug monitoring, compared with standard therapy, did not significantly improve clinical remission rates over 30 weeks. These findings do not support routine use of therapeutic drug monitoring during infliximab induction for improving disease remission rates.
