Influence of rheumatoid factor on serum drug levels of TNF inhibitors with different structures in rheumatoid arthritis.

OBJECTIVES: Certolizumab pegol (CZP), an Fc-free antibody fragment, has shown stable serum levels and steady efficacy in the treatment of RA patients, irrespective of RF levels at baseline. Here, we examine, in clinical practice, the effect of baseline RF and ACPA levels on serum drug levels of IFX, ADL and CZP an Fc-free antibody fragment. METHODS: This is a retrospective study performed in real-world patients. We assessed 170 patients with RA: 90 (53%) received IFX, 48 (28%) ADL and 32 (19%) CZP. Demographic and clinical variables, RF and ACPA levels were obtained at the baseline visit (T0), and patients were stratified based on negative, low, medium, or high levels. After 6 months (T6) serum drug levels and anti-drug antibodies (ADAb), were computed. RESULTS: While CZP serum levels did not differ across RF groups at T6, high baseline RF was linked to lower serum drug levels compared to RF negative status in treatment with complete monoclonal antibodies IFX and ADL. No differences in disease activity measured by DAS28 at baseline were observed across RF quartiles in patients treated with IFX or ADL. ADAb was observed in 26 patients with IFX, 3 with ADL and 1 with CZP, following 6 months of treatment. Patients with high baseline RF levels dropped out more frequently by secondary non-response in IFX or ADL than CZP (80% vs. 75% vs. 33%, p=0.002). CONCLUSIONS: In this real word data evaluation, CZP serum levels were independent of RF levels in patients however patients with high baseline RF levels who obtained IFX or ADL had lower serum drug levels at 6 months than baseline RF-negative patients. In addition, secondary non-response was more frequent in patients with high RF levels treated with IFX and ADL.

High BMI is associated with lower TNF-α inhibitor serum trough levels and higher disease activity in patients with axial spondyloarthritis.

BACKGROUND: TNF-α inhibitor (TNFi) serum trough levels have previously been found to be related to disease activity in axial spondyloarthritis (axSpA). However, most research regarding serum trough levels has been conducted in patients who only recently started TNFi therapy. Therefore, our objective was to explore TNFi serum trough level measurements in relation to disease activity and BMI in the total axSpA population in daily clinical practice, also including patients on long-term TNFi therapy. METHODS: Consecutive patients from the Groningen Leeuwarden Axial Spondyloarthritis (GLAS) cohort were approached for a TNFi serum trough level measurement during their regular outpatient visit at the UMCG. Spearman's correlation coefficient was used to analyse the relation of serum trough levels with disease activity and BMI. Logistic regression was performed to analyse the relation between therapeutic drug levels and disease activity, corrected for potential confounders, including BMI. RESULTS: Thirty-four patients on adalimumab and 21 patients on etanercept were included. Mean age was 45 ± 12 years, 47% were male, median BMI was 26.4 (IQR 23.9-32.5) and median treatment duration was 41 months (range 2-126). According to definitions of Sanquin, 47% of patients had therapeutic serum trough levels. No significant correlations were found between TNFi levels and disease activity (ASDAS-CRP: adalimumab: ρ = -0.16, p = 0.39; etanercept: ρ = -0.29, p = 0.20). TNFi levels were moderately correlated with BMI (adalimumab: ρ = -0.48, p = 0.004; etanercept: ρ = -0.50, p = 0.021). Patients with active disease (ASDAS ≥ 2.1) showed higher BMI than patients with inactive disease (median 29.7 vs. 24.6, p = 0.015). In multivariable regression analyses, BMI was identified as the only confounder for the relationship between therapeutic drug levels and ASDAS. CONCLUSION: In this cross-sectional, observational study of axSpA patients mainly on long-term treatment with TNFi, higher BMI was significantly associated with lower adalimumab and etanercept serum trough levels and higher disease activity.

Analysing cord blood levels of TNF inhibitors to validate the EULAR points to consider for TNF inhibitor use during pregnancy.

BACKGROUND: To minimise placental transfer of tumour necrosis factor inhibitors (TNFi), the European League Against Rheumatism (EULAR) created points to consider (PtC) for the use of TNFi during pregnancy. We are the first to validate the EULAR-PtC by analysing TNFi concentrations in cord blood. METHODS: Patients were derived from the Preconceptional Counselling in Active Rheumatoid Arthritis Study. TNFi was stopped at the time points recommended by the EULAR. Maternal blood and cord blood were collected and analysed for the concentration of TNFi. RESULTS: 111 patients were eligible for the analysis. Median stop time points were gestational age (GA) 37.0 weeks for certolizumab pegol, GA 25.0 weeks for etanercept, GA 19.0 weeks for adalimumab and GA 18.4 weeks for infliximab. Certolizumab pegol (n=68) was detectable in 5.9% of cord blood samples, with a median concentration of 0.3 µg/mL (IQR: 0.2-1.3) and a median cord/maternal concentration ratio of 0.010. Etanercept (n=30) was not detected in any cord blood samples. Adalimumab (n=25) was detectable in 48.0% of cord blood samples, with a median concentration of 0.5 µg/mL (IQR: 0.2-0.7) and a median concentration ratio of 0.062 (IQR: 0.018-0.15). Infliximab (n=14) was detectable in 57.1% of cord blood samples, with a median concentration of 0.4 µg/mL (IQR: 0.1-1.2) and a median concentration ratio of 0.012 (IQR: 0.006-0.081). CONCLUSION: Compliance with the EULAR-PtC results in absence or low levels of TNFi in cord blood.

Management of inflammatory bowel disease and serum level of infliximab in newborn exposed to anti-TNF therapy during pregnancy: Case report and literature review.

RATIONALE: Heightened inflammatory bowel disease (IBD) activity during pregnancy is associated with higher rates of preterm birth, miscarriage, and low birth weight. Therefore, its adequate treatment is essential, considering the risk-benefit of medication use. Although previous literature has described the management of IBD during pregnancy, few studies have assessed the pharmacokinetics of IBD drugs in the newborn. In this case report, we describe the management of ulcerative colitis during pregnancy and discuss the benefits of checking serum levels of infliximab in newborns exposed to the medication during pregnancy. PATIENT CONCERN: A 37-year-old patient with ulcerative colitis in clinical and endoscopic remission had been undergoing treated with infliximab since 2008. The patient became pregnant in 2018. DIAGNOSIS AND INTERVENTION: Infliximab medication was discontinued at the 29th week of pregnancy. OUTCOMES: The pregnancy was uneventful, and the levels of infliximab in the umbilical cord were >20 µg/dL. Live vaccinations were postponed until the baby was 6 months old, when a new serum drug level proved to be undetectable. LESSONS: Our case suggests that the use of infliximab is safe in pregnancy, and drug discontinuation could be considered from the 24th week of pregnancy onward to reduce placental transfer to the newborn in patients at low risk of relapse. Vaccines with live attenuated organisms should be delayed for at least 6 months or until the serum level of the medication is undetectable.

Development of a Flow Cytometry-Based Functional Assay to Study Anti-TNF Mechanisms of Action and Capture Donor Heterogeneity.

TNF is a key cytokine in autoimmune diseases like rheumatoid arthritis, and TNF antagonists are commonly prescribed therapeutics. Although anti-TNF drugs have enabled a very significant progress in this field, disease heterogeneity remains and causes diversity in patient response. These challenges increase the need for anti-TNF characterization tools that may open perspectives toward the development of personalized medicine. In this study, we present a novel whole blood-based flow cytometry functional assay that allows, within a given whole blood sample, the characterization of an anti-TNF molecule mechanisms of action. Whole blood from healthy human donors was employed to mimic the physiological state but also to streamline experimental workflows. Samples were incubated with LPS alone or in combination with various anti-TNF molecules such as adalimumab (ADA), etanercept (ETA), and infliximab. A 10-color flow cytometry panel including CD69, transmembrane TNF, CD16, CD62L, CD66b, CD11b, and CD54 as activation markers was used following a centrifugation-free protocol. CD69 expression decreased on NK, NKT, and T cells upon treatment with ADA, ETA, and IFX as a direct indication of forward signaling neutralization. Percentages of transmembrane TNF+ monocytes increased after incubation when using ADA or IFX but not ETA, revealing the potential of the two first molecules to trigger reverse signaling. Ab-dependent cell cytotoxicity was informed by CD16 and CD69 expressions in some donors that showed increasing levels of CD16- CD69+ NK cells when incubated with anti-TNFs. This study proposes a novel approach to assess anti-TNF mechanisms of action and provides a path toward capturing donor heterogeneity.

Pharmacokinetic Similarity of ABP 710, a Proposed Biosimilar to Infliximab: Results From a Randomized, Single-Blind, Single-Dose, Parallel-Group Study in Healthy Subjects.

This was a randomized, single-blind, single-dose, 3-arm parallel-group study. Healthy subjects were randomized to receive ABP 710 (n = 50) or infliximab reference product (RP) sourced from the United States (infliximab US; n = 50) or the European Union (infliximab EU; n = 50) 5 mg/kg intravenously over 2 hours. The primary endpoint was area under the serum concentration-time curve from time 0 extrapolated to infinity (AUCinf ) for the comparison of ABP 710 to infliximab US and infliximab EU. Secondary endpoints included safety, tolerability, and immunogenicity. AUCinf was similar across the 3 groups, showing similarity of ABP 710 to infliximab RP as well as similarity of infliximab US with infliximab EU. Geometric mean ratio of AUCinf was 0.89 between ABP 710 and infliximab US, 1.00 between ABP 710 and infliximab EU, and 1.11 between infliximab US and infliximab EU. All 90% confidence intervals of the geometric mean ratios were fully contained within the prespecified standard pharmacokinetic equivalence criteria range of 0.80 to 1.25. Treatment-related adverse events were mild to moderate and reported for 83.7%, 86.0%, and 83.7% of subjects in the ABP 710, infliximab US, and infliximab EU treatment groups, respectively; incidence of antidrug antibody rates observed across the 3 groups were similar. Results of this study demonstrated pharmacokinetic similarity of ABP 710 with infliximab RP following a single 5-mg/kg intravenous injection. The safety and tolerability of ABP 710 and infliximab RP were comparable. These results add to the totality of evidence providing further support that the proposed biosimilar ABP 710 is similar to infliximab RP. (Trial ID: ACTRN12614000903684.).

Identification of Target Golimumab Levels in Maintenance Therapy of Crohn's Disease and Ulcerative Colitis Associated With Mucosal Healing.

INTRODUCTION: Golimumab is approved as a therapy for ulcerative colitis (UC) patients. Recent data also demonstrate efficacy in Crohn's disease (CD); however, little is known about target drug levels to achieve endoscopic remission. METHODS: We performed a retrospective analysis of IBD patients on maintenance golimumab. Median trough levels were compared using Kruskal-Wallis test, and logistic regression was used to construct a probabilistic model to determine sensitivity and specificity of levels predicting mucosal healing. RESULTS: Fifty-eight patients on maintenance golimumab were included (n = 39 CD, n = 19 UC/IBD-unclassified [IBDU]). Forty percent (n = 23) were cotreated with an immunomodulator, 95% (n = 55) of patients were anti-TNF experienced, and 15.5% (n = 9) had 3 or more prior biologic therapies. Forty-four percent of patients achieved mucosal healing with endoscopic response in a further 26% of patients. Clinical remission was recorded in 41% of patients, and 82% had clinical response. Patients were treated with doses generally higher than the approved maintenance dose. In CD patients, median golimumab trough levels were higher in patients with mucosal healing (8.8 µg/mL vs 5.08 µg/mL, P = 0.03). After calculation of a receiver operating characteristic (ROC) curve for mucosal healing vs nonresponse, a trough level >8 µg/mL was associated with mucosal healing, with 67% sensitivity, 88% specificity, and a likelihood ratio of 3:4. CONCLUSION: Treatment with golimumab was associated with mucosal healing in 44% of all IBD patients. Higher golimumab levels were associated with mucosal healing in CD. These findings support the need for prospective studies to determine target golimumab levels in IBD, which may impact current clinical practices in relation to selection of maintenance dosing.

Development of a competitive binding homogeneous mobility shift assay for the quantification of adalimumab levels in patient serum.

Adalimumab is a TNF specific monoclonal widely used therapeutically. Monitoring adalimumab levels is important for guiding treatment strategies and is predominantly performed using an ELISA. The homogeneous mobility shift assay (HMSA) has many advantages over an ELISA for adalimumab monitoring but current HMSA methodologies do not discriminate between adalimumab and other TNF specific monoclonals such as infliximab. The development and validation of a competitive binding HMSA (cHMSA) specific for adalimumab is reported here. The cHMSA had a lower limit of quantitation of 1.25 µg/ml and the intra-assay and inter-assay coefficents of variation (CV) were <20%. No signal was detected in adalimumab naïve control serum including those containing rheumatoid factor or infliximab. The majority (14/20) of adalimumab patient samples containing anti-adalimumab antibodies gave a cHMSA signal >3 standard deviations lower than the controls. The performance of the cHMSA and an ELISA was compared using adalimumab patient samples (n = 82). There was a strong correlation between the assays (r = 0.91) and the intra-class correlation coefficient (0.88) was indicative of good-excellent inter-assay reliability. Bland-Altman plots showed little overall bias and comparison of the sub-groups defined using cut-points (1.25 or 7.3 µg/ml) gave percent agreement (>90%) and Cohens kappa (95% CI: 0.61-0.93) values indicative of substantial-almost perfect agreement. These results demonstrate that cHMSA provides an accurate and specific method for monitoring adalimumab levels and can additionally provide an initial screen for the presence of anti-adalimumab antibodies.

Drug Levels and Antibodies Against TNF-blockers in Spondyloarthritis and Rheumatoid Arthritis are Associated with the Activity but they do Not Predict it.

BACKGROUND: Many patients may have resistance to TNF-blockers. These drugs may induce neutralizing antibodies. The determination of the drug levels of TNF-blockers and Anti-Drug Antibodies (ADAs) against TNF-blockers may help to make clinical decisions. OBJECTIVES: The objective of this study was to associate and predict the drug levels of TNFblockers and ADAs in relation to disease activity in patients with Spondyloarthritis (SpA) and Rheumatoid Arthritis (RA). METHODS: Cross-sectional study including patients fulfilling ASAS classification criteria for SpA and 2010 ACR-EULAR classification criteria for RA. These patients were treated with Adalimumab (ADA), Infliximab (IFX), and Etanercept (ETN). A bivariate analysis and the chi-square test were performed to evaluate the association of ADAs and drug levels with activity measures for SpA and RA. Five regression models analyzing drug levels, ADAs and disease activity measures using a multiple linear regression were performed in order to evaluate the prediction of ADAs and drug levels in relation to disease activity. RESULTS: In SpA, IFX levels were associated with BASDAI (Bath Ankylosing Spondylitis Disease Activity Index) (p=0.034). In RA, total drug levels were associated with DAS28-ESR (28 joint Disease activity Score-erythrocyte sedimentation rate), (p=0.008), DAS28-CRP (p=0.042), CDAI (Clinical Disease Activity Index) (p=0.047) and SDAI (Simple Disease activity index), (p=0.017). ADA levels had association with CDAI (p=0.002) and SDAI (p=0.002). IFX levels were associated with a DAS28-ESR (p=0.044), DAS28-CRP (p=0.022) and SDAI (p=0.022). ADAs were associated in SpA with BASDAI (p=0.027). Drug levels and ADAs did not predict disease activity in patients with SpA or RA. CONCLUSION: ADAs and drug levels of anti-TNF are associated with disease activity measures in patients with SpA and RA. However, they cannot predict clinical activity in these conditions.

Comparison of Adalimumab Serum Drug Levels When Delivered by Pen Versus Syringe in Patients With Inflammatory Bowel Disease. An International, Multicentre Cohort Analysis.

BACKGROUND: Adalimumab is administered via a pre-filled syringe or spring-loaded pen. In a previous study in Crohn's disease, higher drug levels were observed in syringe users. The aim of this study was to evaluate the impact of delivery device on adalimumab drug levels in patients with Crohn's disease. METHODS: Consecutive Crohn's disease patients treated with maintenance adalimumab [40 mg fortnightly] were recruited from five centres. The first recorded drug level with matched clinical and biochemical markers of disease activity was compared between pen and syringe users. RESULTS: Of 218 patients, 64% used pen, with a median faecal calprotectin 110 µg/g and serum C-reactive protein 4 mg/L. In comparison to pen, syringe users had higher albumin [39 vs 42 g/L; p = 0.016], lower Harvey-Bradshaw Index [2 vs 1; p = 0.017], and higher rates of concomitant immunomodulation [54% vs 71%; p = 0.014]. Drug levels were equivalent between pen and syringe users [median 5.3 vs 5.2 µg/ml; p = 0.584], even after controlling for disease activity and immunomodulation. Syringe users at Alfred Health had higher drug levels than pen [6.1 vs 4.5 µg/ml; p = 0.039]; a greater proportion achieved therapeutic levels [75% vs 44%; p = 0.045]. A higher proportion of pen users from Saint-Étienne had therapeutic levels [79% vs 42%; p = 0.027], yet no significant difference in drug levels [7.9 vs 4.5 µg/ml; p = 0.119]. CONCLUSIONS: Delivery device does not appear to significantly affect adalimumab drug levels. Given differences between study sites, studies evaluating administration education and technique are warranted.

Higher adalimumab serum levels do not increase the risk of adverse events in patients with inflammatory bowel disease.

Background: The relationship between serum adalimumab concentrations and adverse events in patients with inflammatory bowel disease (IBD) is unknown. We aimed to determine whether patients with IBD using adalimumab are at increased risk of adverse events if they have higher adalimumab serum levels compared to those with lower adalimumab levels. Methods: This was a retrospective study of 191 IBD patients with at least one serum adalimumab level measurement available. The cohort was divided using a cutoff level of 10 mcg/mL. The primary outcome was the rate of overall adverse events between the two groups. Secondary outcomes included rate of infections, dermatologic reactions, injection-site reactions and other adverse events in both groups. Rates of discontinuation of adalimumab due to adverse events were evaluated. Multivariate logistic regression analysis was performed to evaluate the relationship between adalimumab levels and adverse events. Results: A total of 41 adverse events were reported in 191 patients in the overall cohort. Among 86 patients with higher adalimumab levels, 22 adverse events were reported, vs. 19 adverse events among 105 patients with lower adalimumab levels (25.6% vs. 18.1%, p = .21). Analysis according to adalimumab level tertiles also did not show significant differences in the rates of adverse events. A multivariate forward selection model also did not find higher odds of an adverse event in IBD patients with higher adalimumab levels compared to lower levels (OR 1.54, 95% CI 0.77-3.08). Conclusions: There does not appear to be a relationship between adalimumab exposure and risk of adverse events in IBD patients.

Clinical relevance of monitoring serum adalimumab levels in axial spondyloarthritis.

Our aim was to assess the relationship between serum adalimumab levels, anti-drug antibodies (ADA) and disease activity in patients with axial spondylarthritis (SpA). We have carried out a single-centre cross-sectional study. adalimumab and ADA levels were analysed with ELISA and correlated with SpA activity using BASDAI and ASDAS scores. Adalimumab cut-off value was calculated to discriminate inactive disease/low disease activity (BASDAI < 4; ASDAS < 2.1) from moderate/high disease activity (BASDAI ≥ 4; ASDAS ≥ 2.1), using a receiver operating characteristic (ROC) curve. Up to January 2016, 51 consecutive patients were included. The median (range) age was 46.6 (18-68) and 47.1% were women. ADA prevalence was 27.5%, with none detected in the 21.6% receiving concomitant disease-modifying antirheumatic drugs (DMARDs) (p = 0.021). Adalimumab level was normal (> 3 mg/l) in 36 patients (70.6%), all without ADA. Fifteen patients (29.4%) had subtherapeutic adalimumab levels (< 3 mg/l), with ADA in 14 (93%). Median adalimumab (mg/l) was significantly higher in patients with inactive disease/low disease activity: BASDAI < 4 vs ≥ 4: 9.5 vs 2.6 (p < 0.01); ASDAS-CRP < 2.1 vs ≥ 2.1: 9.3 vs 0.3 (p < 0.001); ASDAS-ESR < 2.1 vs ≥ 2.1: 9.9 vs 3.0 (p < 0.001), and this finding was consistent with the result of the multivariate model. Patients with inactive disease/low disease activity presented significantly lower ADA levels. The adalimumab level cut-offs and area under the curve (AUC) obtained in the ROC curves were: ASDAS-CRP (< 2.1) 4.6 mg/l (AUC 81.2%; 95% CI 67.5-94.9; p < 0.001); ASDAS-ESR (< 2.1) 7.7 mg/l (AUC 82.4%; 95% CI 69.3-95.5; p < 0.001); BASDAI (< 4) 6.4 mg/l (AUC 73.5%; 95% CI 58.6-88.3; p < 0.01). In conclusion, presence of ADA in axial SpA patients treated with adalimumab was associated with lower serum drug levels. ADA levels were lower and adalimumab levels were higher in patients with inactive disease/low disease activity based on BASDAI and ASDAS indices. Concomitant treatment with MTX reduces de likelihood of finding ADA. Serum adalimumab levels above 4.6 mg/l are recommended to avoid compromising efficacy.