Inefficacy of infliximab in ankylosing spondylitis is correlated with antibody formation

Drug Survival of Biologics in Treating Ankylosing Spondylitis: A Systematic Review and Meta-analysis of Real-World Evidence

BACKGROUND

The last decade has witnessed the increasing use of biologics for the treatment of ankylosing spondylitis (AS). Drug survival is an outcome incorporating real-world effectiveness and safety. However, the drug survival of biologics in treating AS is unclear.

OBJECTIVE

The aim was to assess the drug survival of biologics (tumor necrosis factor inhibitors and anti-interleukin-17 monoclonal antibodies) in treating AS.

METHODS

We conducted a systematic review and meta-analysis and searched the PubMed, Cochrane Central Register of Controlled Trials (CENTRAL), and Embase databases up to 13th May 2020. Studies that analyzed the drug survival of biologics for AS and reported the respective annual data for each biologic for at least 1 year were included. Two authors independently screened and selected studies and assessed their risk of bias. A third author was available for arbitrating discrepancies. The Newcastle-Ottawa Scale was employed to evaluate the risk of bias of included studies. We conducted a random-effects model meta-analysis to obtain pooled drug survival from year 1 to 5. We performed subgroup analyses for biologic-naïve patients, first-line versus second- and third-line biologics, discontinuation due to loss of effectiveness and adverse effects, and high-quality studies.

RESULTS

We included 39 studies with 32,493 patients. The drug survival decreased from 76% at year 1 to 51% at year 5 for etanercept, from 75 to 51% for adalimumab, from 76 to 53% for infliximab, from 72 to 49% for golimumab, and from 63 to 57% for certolizumab pegol. The drug survival rate for secukinumab was 0.77 (95% confidence interval 0.64‒0.90) at year 1. Subgroup analyses on biologic-naïve patients and discontinuation due to adverse effects found no differences in the drug survival of various biologics except for a lower drug survival of infliximab in biologic-naïve patients. The drug survival for first-line biologics was higher than for second- and third-line biologics.

CONCLUSION

To the best of our knowledge, this study is the first systematic review and meta-analysis on the drug survival of biological therapies for AS patients. The drug survival of all biologics in treating AS appeared comparable, but is higher in first-line biologics than second- and third-line biologics. To date there are scarce data on the drug survival of newly available biologics, for example, anti-interleukin-17 biologics.

PROSPERO REGISTRATION NO

CRD42018114204.

The Molecular Mechanisms That Underlie the Immune Biology of Anti-drug Antibody Formation Following Treatment With Monoclonal Antibodies

Monoclonal antibodies (mAbs) are a crucial asset for human health and modern medicine, however, the repeated administration of mAbs can be highly immunogenic. Drug immunogenicity manifests in the generation of anti-drug antibodies (ADAs), and some mAbs show immunogenicity in up to 70% of patients. ADAs can alter a drug's pharmacokinetic and pharmacodynamic properties, reducing drug efficacy. In more severe cases, ADAs can neutralize the drug's therapeutic effects or cause severe adverse events to the patient. While some contributing factors to ADA formation are known, the molecular mechanisms of how therapeutic mAbs elicit ADAs are not completely clear. Accurate ADA detection is necessary to provide clinicians with sufficient information for patient monitoring and clinical intervention. However, ADA assays present unique challenges because both the analyte and antigen are antibodies, so most assays are cumbersome, costly, time consuming, and lack standardization. This review will discuss aspects related to ADA formation following mAb drug administration. First, we will provide an overview of the prevalence of ADA formation and the available diagnostic tools for their detection. Next, we will review studies that support possible molecular mechanisms causing the formation of ADA. Finally, we will summarize recent approaches used to decrease the propensity of mAbs to induce ADAs.

Exposure-Response Relationship of Certolizumab Pegol and Achievement of Low Disease Activity and Remission in Patients With Rheumatoid Arthritis

Anti-tumor necrosis factor (anti-TNF) drugs are often prescribed for the treatment of rheumatoid arthritis (RA) and other immune-mediated inflammatory diseases. Although this treatment has been shown to be effective in many patients, up to 40% of patients do not achieve disease control. Drug concentration in plasma may be a factor affecting the observed variability in therapeutic response. In this study, we aimed to identify the plasma concentrations of the anti-TNF certolizumab pegol (CZP), associated with improvement in disease activity in patients with RA. Data were pooled from three randomized, controlled clinical trials with a combined total of 1,935 patients analyzed. Clinical outcomes of low disease activity (LDA) and remission were defined as Disease Activity Score in 28 joints with C-reactive protein (DAS28(CRP)) ≤ 2.7 and < 2.3, respectively. Quartile analysis results indicated that there may be an exposure-response relationship between CZP concentration and LDA/remission outcomes at weeks 12 and 24; the association was strongest for LDA (P < 0.05). Receiver operating characteristic (ROC) analysis showed that CZP concentrations ≥ 28.0 μg/ml at week 12, and ≥ 17.6 μg/ml at week 24, were associated with a greater likelihood of achieving LDA/remission outcomes. Although confirmatory studies are warranted to define the optimal CZP therapeutic range at weeks 12 and 24, these data indicate that CZP concentrations may be associated with improvement of disease activity.

An update on serum biomarkers to assess axial spondyloarthritis and to guide treatment decision

Axial spondyloarthritis (axSpA) is a group of debilitating, chronic, rheumatic conditions characterized by inflammation and new bone formation, mainly involving the spine and the sacroiliac joints. The lack of biomarkers in axSpA is well known. Despite significant treatment advances in recent years thanks to the introduction of drugs with a new mode of action, such as new biologic and targeted synthetic disease-modifying antirheumatic drugs, no relevant improvement in the identification of disease biomarkers has been achieved. Common parameters, such as erythrocyte sedimentation rate and C-reactive protein, which are routinely used to measure systemic inflammation, are the sole markers available to date and are not adequate to assess disease activity in all patients. The aim of this study is to review the most promising serum biomarkers that may help treatment decision in axSpA via a proper assessment of disease activity and identification of negative prognostic factors.

Understanding Inter-Individual Variability in Monoclonal Antibody Disposition

Monoclonal antibodies (mAbs) are currently the largest and most dominant class of therapeutic proteins. Inter-individual variability has been observed for several mAbs; however, an understanding of the underlying mechanisms and factors contributing to inter-subject differences in mAb disposition is still lacking. In this review, we analyze the mechanisms of antibody disposition and the putative mechanistic determinants of inter-individual variability. Results from in vitro, preclinical, and clinical studies were reviewed evaluate the role of the neonatal Fc receptor and Fc gamma receptors (expression and polymorphism), target properties (expression, shedding, turnover, internalization, heterogeneity, polymorphism), and the influence of anti-drug antibodies. Particular attention is given to the influence of co-administered drugs and disease, and to the physiological relevance of covariates identified by population pharmacokinetic modeling, as determinants of variability in mAb pharmacokinetics.

Factors associated with ASDAS remission in a long-term study of ankylosing spondylitis patients under tumor necrosis factor inhibitors

OBJECTIVE

To determine the clinical and demographic factors associated with disease remission and drug survival in patients with ankylosing spondylitis (AS) on TNF inhibitors.

METHODS

Data from a longitudinal electronic database of AS patients under anti-TNF therapy between June/2004 and August/2013. Demographic, clinical parameters, disease activity by ASDAS remission (< 1.3) and inactive/low (< 2.1) were analyzed to characterize reasons for drug survival and switching of anti-TNF.

RESULTS

Among 117 AS patients, 69 (59%) were prescribed only one anti-TNF, 48 (41%) switched to a second anti-TNF and 13 (11%) to a third anti-TNF. Considering ASDAS-CRP < 1.3, 31 (39%) patients were inactive at the end of the study. Non-switchers (P = 0.04), younger age (P = 0.004), non-smoking (P = 0.016), shorter disease duration (P = 0.047), more frequent use of SSZ (P = 0.037) and lower BASDAI (P = 0.027), BASMI (P = 0.034) and BASFI (P = 0.003) at baseline were associated with remission. In the multivariate analysis younger age (P = 0.016) and lower BASDAI (P = 0.032) remained as remission predictors.

CONCLUSION

This study supports that ASDAS-CRP remission is an achievable goal not only for non-switchers but also for second anti-TNF, particularly in patients with younger age and lower BASDAI at baseline. Co-medication and non-smoker status seems to have a beneficial effect in anti-TNF response in this population.

Current Practice for Therapeutic Drug Monitoring of Biopharmaceuticals in Spondyloarthritis

Treatment of spondyloarthritis (SpA) has greatly improved in the biopharmaceutical era. These compounds, primarily tumor necrosis factor inhibitors, are effective, but some patients may show poor response, sometimes due to the presence of antidrug antibodies (ADAs). In some instances, clinicians may increase or taper the dose, depending on the clinical response. Besides the current clinical practice, a tailored strategy based on drug monitoring is emerging as a way to improve the use of these drugs. However, the relevance of this therapeutic drug monitoring of biopharmaceuticals for SpA is still unknown. In this literature review, we examined the most relevant articles dealing with the concentration-response relation, ADA detection, and pharmacokinetics in SpA treated with biopharmaceuticals. ADAs were associated with low or undetectable concentration of monoclonal antibodies. The relation between drug concentration and clinical response in SpA is debated, some studies showing an association and others not. Therefore, therapeutic drug monitoring of biopharmaceuticals for SpA requires a better understanding of the association among the pharmacokinetics, pharmacodynamics, and immunogenicity of these drugs.

Immunogenicity and loss of response to TNF inhibitors: implications for rheumatoid arthritis treatment

The availability of monoclonal antibodies has revolutionized the treatment of an increasingly broad spectrum of diseases. Inflammatory diseases are among those most widely treated with protein-based therapeutics, termed biologics. Following the first large-scale clinical trials with monoclonal antibodies performed in the 1990s by rheumatologists and clinical immunologists, the approval of these agents for use in daily clinical practice led to substantial progress in the treatment of rheumatic diseases. Despite this progress, however, only a proportion of patients achieve a long-term clinical response. Data on the use of agents blocking TNF, which were among the first biologics introduced into clinical practice, provide ample evidence of primary and secondary treatment inefficacy in patients with rheumatoid arthritis (RA). Important issues relevant to primary and secondary failure of these agents in RA include immunogenicity, methodological problems for the detection of antidrug antibodies and trough drug levels, and the implications for treatment strategies. Although there is no strong evidence to support the routine estimation of antidrug antibodies or serum trough levels during anti-TNF therapy, these assessments might be helpful in a few clinical situations; in particular, they might guide decisions on switching the therapeutic biologic in certain instances of secondary clinical failure.

Practical recommendations for the use of therapeutic drug monitoring of biopharmaceuticals in inflammatory diseases

Biopharmaceuticals directed against tumor necrosis factor-alpha, integrins, interleukins, interferons and their receptors have become key agents for the management of inflammatory diseases in the fields of gastroenterology, rheumatology, dermatology and neurology. However, response to these treatments is far from optimal. Therapeutic failure has been attributed in part to inadequate serum concentrations of the drug and the formation of antidrug antibodies (ADA). Therapeutic drug monitoring (TDM) based on drug concentrations and ADA represents a pharmacologically sound tool for guiding dosage adjustments to optimize exposure. Although becoming standard practice in tertiary care centers, the widespread accessibility and recognition of TDM is hindered by several hurdles, including a lack of education of health care providers on TDM. In this paper, the Monitoring of monoclonal Antibodies Group in Europe (MAGE) provides an introduction on the fundamental principles of the concept of TDM, aiming to educate clinicians and assist them in the process of implementing TDM of anti-inflammatory biopharmaceuticals.

Potential Sources of Inter-Subject Variability in Monoclonal Antibody Pharmacokinetics

Understanding inter-subject variability in drug pharmacokinetics and pharmacodynamics is important to ensure that all patients attain suitable drug exposure to achieve efficacy and avoid toxicity. Inter-subject variability in the pharmacokinetics of therapeutic monoclonal antibodies (mAbs) is generally moderate to high; however, the factors responsible for the high inter-subject variability have not been comprehensively reviewed. In this review, the extent of inter-subject variability for mAb pharmacokinetics is presented and potential factors contributing to this variability are explored and summarised. Disease status, age, sex, ethnicity, body size, genetic polymorphisms, concomitant medication, co-morbidities, immune status and multiple other patient-specific details have been considered. The inter-subject variability for mAb pharmacokinetics most likely depends on the complex interplay of multiple factors. However, studies aimed at investigating the reasons for the inter-subject variability are sparse. Population pharmacokinetic models and physiologically based pharmacokinetic models are useful tools to identify important covariates, aiding in the understanding of factors contributing to inter-subject variability. Further understanding of inter-subject variability in pharmacokinetics should aid in development of dosing regimens that are more appropriate.

Higher body mass index and anti-drug antibodies predict the discontinuation of anti-TNF agents in Korean patients with axial spondyloarthritis

OBJECTIVE

The development of anti-drug antibodies against tumor necrosis factor inhibitors is a likely explanation for the failure of TNF-inhibitors in patients with spondyloarthritis. Our study determined the existence and clinical implications of ADAbs in axial spondyloarthritis patients.

METHODS

According to the Assessment of SpondyloArthritis International Society classification criteria for axial spondyloarthritis, patients treated with adalimumab or infliximab were recruited consecutively. Serum samples were collected at enrollment to measure anti-drug antibodies and drug levels.

RESULTS

Of 100 patients, the mean duration of current TNF inhibitor use was 22.3±17.9 months. Anti-drug antibodies were detected in 5 of 72 adalimumab users compared to 5 of 28 infliximab users (6.9% vs. 17.9%). Anti-drug antibodies-positive patients had a significantly higher body mass index than anti-drug antibodies-negative patients among both adalimumab (28.4±5.9kg/m² vs. 24.3±2.9kg/m², respectively, p=0.01) and infliximab users (25.9±2.8kg/m² vs. 22.6±2.8kg/m², respectively, p=0.02). During the median 15-month follow-up period, drug discontinuation occurred more frequently in the anti-drug antibodies-positive group than the anti-drug antibodies-negative group (30.0% vs. 6.5%, respectively, p=0.04). In logistic regression, anti-drug antibodies positivity (OR=5.85, 95% CI 1.19-28.61, p=0.029) and body mass index (OR=4.35, 95% CI 1.01-18.69, p=0.048) were associated with a greater risk of stopping TNF inhibitor treatment.

CONCLUSIONS

Our result suggests that the presence of anti-drug antibodies against adalimumab and infliximab as well as a higher body mass index can predict subsequent drug discontinuation in axial spondyloarthritis patients.

Higher body mass index and anti-drug antibodies predict the discontinuation of anti-TNF agents in Korean patients with axial spondyloarthritis

OBJECTIVE

The development of anti-drug antibodies (ADAbs) against tumor necrosis factor (TNF) inhibitors is a likely explanation for the failure of TNF-inhibitors in patients with spondyloarthritis (SpA). Our study determined the existence and clinical implications of ADAbs in axial SpA patients.

METHODS

According to the Assessment of SpondyloArthritis International Society classification criteria for axial SpA, patients treated with adalimumab or infliximab were recruited consecutively. Serum samples were collected at enrollment to measure ADAb and drug levels.

RESULTS

Of 100 patients, the mean duration of current TNF inhibitor use was 22.3±17.9 months. ADAbs were detected in 5 of 72 adalimumab users compared to 5 of 28 infliximab users (6.9% vs. 17.9%). ADAb-positive patients had a significantly higher body mass index than ADAb-negative patients among both adalimumab (28.4±5.9kg/m2 vs. 24.3±2.9kg/m2, respectively, p=0.01) and infliximab users (25.9±2.8kg/m2 vs. 22.6±2.8kg/m2, respectively, p=0.02). During the median 15-month follow-up period, drug discontinuation occurred more frequently in the ADAb-positive group than the ADAb-negative group (30.0% vs. 6.5%, respectively, p=0.04). In logistic regression, ADAb positivity (OR=5.85, 95% CI 1.19-28.61, p=0.029) and BMI (OR=4.35, 95% CI 1.01-18.69, p=0.048) were associated with a greater risk of stopping TNF inhibitor treatment.

CONCLUSIONS

Our result suggests that the presence of ADAbs against adalimumab and infliximab as well as a higher BMI can predict subsequent drug discontinuation in axial SpA patients.

Unraveling the Effect of Immunogenicity on the PK/PD, Efficacy, and Safety of Therapeutic Proteins

Biologics have emerged as a powerful and diverse class of molecular and cell-based therapies that are capable of replacing enzymes, editing genomes, targeting tumors, and more. As this complex array of tools arises a distinct set of challenges is rarely encountered in the development of small molecule therapies. Biotherapeutics tend to be big, bulky, polar molecules comprised of protein and/or nucleic acids. Compared to their small molecule counterparts, they are fragile, labile, and heterogeneous. Their biodistribution is often limited by hydrophobic barriers which often restrict their administration to either intravenous or subcutaneous entry routes. Additionally, their potential for immunogenicity has proven to be a challenge to developing safe and reliably efficacious drugs. Our discussion will emphasize immunogenicity in the context of therapeutic proteins, a well-known class of biologics. We set out to describe what is known and unknown about the mechanisms underlying the interplay between antigenicity and immune response and their effect on the safety, efficacy, pharmacokinetics, and pharmacodynamics of these therapeutic agents.

The clinical relevance of early anti-adalimumab antibodies detection in rheumatoid arthritis, ankylosing spondylitis and psoriatic arthritis: A prospective multicentre study

OBJECTIVES

To evaluate the relevance of anti-adalimumab (anti-ADA) antibodies (Abs) and their relationship with clinical/laboratory features in rheumatoid arthritis (RA), ankylosing spondylitis (AS) and psoriatic arthritis (PsA).

METHODS

Fifty-eight patients affected with RA, AS and PsA were prospectively enrolled. Clinical/laboratory characteristics, disease activity, anti-ADA, anti-nuclear (ANA), anti-double strand (ds)DNA, anti-extractable nuclear antigens (anti-ENA) and anti-phospholipid Abs (aPL) were evaluated at baseline, 4, 12 and 24 weeks of adalimumab treatment.

RESULTS

Anti-ADA Abs were observed in 11/58 (19%) patients; they were detected within the 4th week of therapy in 90.9% of the positive subjects. Anti-ADA positivity was associated with significantly lower mean adalimumab serum levels (P<0.05). Treatment failure was observed in 20/58 (34.5%) patients and was significantly associated with anti-ADA Abs (P<0.05). Mean adalimumab serum levels were significantly lower in patients with treatment failure than in the responders one, both in the whole cohort (P<0.01) and in the group of anti-ADA positive patients (P<0.01). Adverse events happened more often in anti-ADA positive then in anti-ADA negative patients (27.3% vs 14.9%).

CONCLUSIONS

Anti-ADA abs could be considered an early marker associated to a poor clinical response to adalimumab treatment. Routine ANA/anti-ENA/aPL monitoring did not reveal as useful tools to predict the development of anti-ADA abs.

The Association between Clinical Response to Ustekinumab and Immunogenicity to Ustekinumab and Prior Adalimumab

Background

Immunogenicity due to antidrug antibodies (ADA) to tumor necrosis factor (TNF)-α antagonists is known to decrease treatment response. However, few studies have investigated ADA in ustekinumab, an interleukin-12 and -23 antagonist, in a clinical setting. This study aimed to investigate the immunogenicity of ustekinumab and its clinical consequences in psoriasis.

Methods

This prospective observational study enrolled 76 patients with plaque psoriasis who were treated with ustekinumab for a minimum of 7 months. Blood samples were drawn just prior to scheduled ustekinumab injection during clinic visits. Levels of anti-ustekinumab antibody (AUA) and serum ustekinumab concentration were measured respectively by radioimmunoassays and enzyme-linked immunoassays respectively, and correlated to clinical data and Psoriasis Area and Severity Index (PASI).

Results

AUA was detected in 6.5% of patients after a mean of 13 months of treatment. Patients with positive AUA had significantly lower serum ustekinumab concentrations (0.01 vs. 0.2 mg/L, p<0.001) and lower PASI 50 response than patients without AUA (0% vs. 69%, p = 0.004).The percentage of AUA formation was comparable between patients who had failed previous adalimumab with or without anti-adalimumab antibodies (AAA) (14.3% vs. 12.5%, p = 1.00). However, a higher proportion of switchers without AAA obtaining PASI50 (71.4% vs. 37.5%) and PASI75 response (42.9% vs.12.5%) within 7 months of ustekinumab treatment than with AAA though this difference did not reach statistical significance.

Conclusions

Our results suggest that presence of AUA was significantly associated with treatment failure for ustekinumab, though limited by a small sample size. Also, determining the presence of ADA to antecedent TNF-α antagonists may assist in choosing an optimized subsequent treatment modality achieving treatment success.

Influence of Immunogenicity on the Efficacy of Long-Term Treatment with TNF α Blockers in Rheumatoid Arthritis and Spondyloarthritis Patients

Objective. To analyze the clinical relevance of the levels of TNFα blockers and anti-drug antibodies (anti-drug Ab) in patients with rheumatoid arthritis (RA) and spondyloarthritis (SpA) treated with adalimumab (ADA), etanercept (ETA), or infliximab (INF) for a prolonged period of time. Methods. Clinical characteristics (disease activity, and adverse events), serum TNFα blockers, and anti-drug Ab levels were evaluated in 62 RA and 81 SpA patients treated with TNFα blockers for a median of 28 months. Results. Anti-ADA Ab were detected in 1 (4.0%) and anti-INF Ab in 14 out of 57 (24.6%) RA and SpA patients. Patient with anti-ADA Ab and 57.1% patients with anti-INF Ab were considered nonresponders to treatment. Anti-ETA Ab were not found in any of 61 ETA treated patients. Anti-ADA and anti-INF Ab levels differ between responders and nonresponders (P > 0.05). Three (5.3%) patients with high serum anti-INF Ab levels developed infusion related reactions. Patients with anti-INF Ab more often required changing to another biologic drug (OR 11.43 (95% CI 1.08–120.93)) and treatment discontinuation (OR 9.28 (95% CI 1.64–52.52)). Conclusion. Patients not responding to treatment had higher serum anti-ADA and anti-INF Ab concentrations. Anti-INF Ab formation is related to increased risk of infusion related reactions, changing to another biologic drug, and treatment discontinuation.

The effect of comedication with conventional synthetic disease modifying antirheumatic drugs on TNF inhibitor drug survival in patients with ankylosing spondylitis and undifferentiated spondyloarthritis: results from a nationwide prospective study

Objective

To assess the effect of comedication with conventional synthetic disease modifying antirheumatic drugs (csDMARDs) on retention to tumour necrosis factor inhibitor (TNFi) therapy in patients with ankylosing spondylitis (AS) and undifferentiated spondyloarthritis (uSpA).

Methods

Data on patients with a clinical diagnosis of AS or uSpA starting treatment with adalimumab, etanercept or infliximab as their first TNFi during 2003–2010 were retrieved from the Swedish national biologics register and linked to national population based registers. Five-year drug survival was analysed by Cox regression with age, sex, baseline csDMARD comedication, TNFi type, prescription year and covariates representing frailty and socioeconomic status. AS and uSpA were analysed separately. Sensitivity analyses included models with csDMARD as a time-dependent covariate and adjustments for additional potential confounders.

Results

1365 patients with AS and 1155 patients with uSpA were included, of whom 40.8% versus 50.3% used csDMARD comedication at baseline. In the unadjusted analyses superior drug survival was observed for patients using versus not using csDMARD comedication among patients with AS (p<0.001) but not among patients with uSpA (p=0.175). In the multivariable Cox regression analyses comedication with csDMARD was associated with better retention to TNFi therapy both in AS (HR 0.71, p<0.001) and uSpA (HR 0.82, p=0.020). The results were similar with csDMARD comedication as a time-dependent covariate, and the associations were retained when adjusting for erythrocyte sedimentation rate, C-reactive protein, patient global, swollen joints, uveitis, psoriasis and inflammatory bowel disease.

Conclusions

In this large register study of patients with AS and uSpA, use of csDMARD comedication was associated with better 5-year retention to the first TNFi.

Prevalence of TNF-α Blocker Immunogenicity in Psoriatic Arthritis

Objective.

The longterm use of tumor necrosis factor (TNF)-α blockers is limited by the formation of neutralizing antibodies. To the best of our knowledge, immunogenicity in psoriatic arthritis (PsA) has not been investigated in depth. Our objective was to evaluate the prevalence and significance of TNF-α blocker immunogenicity in PsA.

Methods.

Consecutive patients with PsA treated with either infliximab (IFX), adalimumab (ADA), or etanercept (ETN) > 3 months participated in our cross-sectional study. Their demographic and clinical characteristics, skin and joint disease activity, and records of use of methotrexate (MTX) and other medications were collected. Drug levels (ELISA) and antidrug antibodies (ADAb; Bridging ELISA) were evaluated before the next injection or infusion.

Results.

A total of 93 patients with PsA were recruited (48 receiving ADA, 24 IFX, and 21 ETN), with a mean age of 53 years (range 21–83 yrs), composed of 53% women. One-fourth of the patients were concomitantly treated with MTX. Altogether, 77% of the patients demonstrated therapeutic drug levels. High levels of ADAb were found in 29% of patients taking ADA, 21% taking IFX, and 0% taking ETN. ADAb significantly correlated with lower drug levels, higher 28-joint Disease Activity Scores, and higher global assessments. MTX use correlated significantly with a lower prevalence of ADAb.

Conclusion.

Significant levels of ADAb were present in up to 29% of patients with PsA treated with ADA or IFX. ADAb clearly correlated with low therapeutic drug levels and higher disease activity variables. The use of MTX significantly decreased ADAb prevalence, and its use should be strongly considered in combination with TNF-α blocker antibodies in patients with PsA.

Adalimumab serum levels and antidrug antibodies towards adalimumab in peripheral spondyloarthritis: no association with clinical response to treatment or with disease relapse upon treatment discontinuation

Introduction

In this study, we evaluated the clinical relevance of serum drug levels and antidrug antibodies (ADAbs) with regard to response to treatment, as well as to relapse upon treatment discontinuation, in peripheral spondyloarthritis (pSpA) patients treated with adalimumab.

Methods

The study included 26 pSpA patients treated with adalimumab for either 12 weeks (n = 12) or 24 weeks (n = 14) in a randomized controlled trial. Patients achieving inactive disease measured by Ankylosing Spondylitis Disease Activity Score (ASDAS) at the end of the treatment period were classified as responders. Clinical characteristics, serum trough adalimumab levels and ADAbs were assessed at the end of the treatment period and at follow-up (upon relapse or, in absence of relapse, at 16 weeks after discontinuation).

Results

Serum adalimumab levels measured 2 weeks after the last adalimumab administration ranged from <0.002 to 23.0 μg/ml, with a median of 11.5 μg/ml. These levels were associated with neither response to treatment or disease activity measurements at the end of treatment nor with the occurrence of relapse and time to relapse after discontinuation of treatment. Antiadalimumab ADAbs were present in 23% of the patients at end of treatment and in 35% at follow-up after treatment discontinuation, indicating that ADAbs were masked by the presence of the drug in some patients. However, ADAbs at the end of treatment and at follow-up were not different between responders and nonresponders and were not associated with relapse upon discontinuation of treatment.

Conclusions

There is no clear association between adalimumab serum levels or antiadalimumab ADAbs with clinical response to treatment or with relapse upon treatment discontinuation in pSpA.

Trial registration

Netherlands Trial Register ID: NTR1806 (registered 7 May 2009)

Strategic characterization of anti-drug antibody responses for the assessment of clinical relevance and impact

All therapeutic proteins have the potential to induce anti-drug antibodies (ADA). Clinically relevant ADA can impact efficacy and/or safety of a biological therapeutic. Immunogenicity assessment strategy evaluates binding and neutralizing ADA, and the need for additional characterization (e.g., epitope, titer and so on) is determined using a risk-based approach. The choice of characterization assays depends on the type, application and immunogenicity of the therapeutic. ADA characterization can impact the interpretation of the risk profile of a given therapeutic, and offers insight into opportunities for risk mitigation and management. This article describes common ADA characterization methods. Strategic assessment and characterization of clinically relevant ADA are discussed, in order to support clinical options for safe and effective patient care and disease management.

Biological therapies for spondyloarthritis

Biological therapies and new imaging techniques have changed the therapeutic and diagnostic approach to spondyloarthritis. In patients with axial spondyloarthritis, tumor necrosis factor α (TNFα) inhibitor treatment is currently the only effective therapy in patients for whom conventional therapy with nonsteroidal anti-inflammatory drugs (NSAIDs) has failed. TNFα inhibitor treatment is more effective in preventing articular damage in peripheral joints than in axial ones. It is important to treat patients at an early stage of disease to reduce disease progression; moreover it is necessary to identify causes of therapy inefficacy in preventing joint damage in the axial subset.

The immunogenicity to the first anti-TNF therapy determines the outcome of switching to a second anti-TNF therapy in spondyloarthritis patients

Introduction

Anti-TNF drugs have proven to be effective against spondyloarthritis (SpA), although 30% of patients fail to respond or experience adverse events leading to treatment discontinuation. In rheumatoid arthritis, the presence of anti-drug antibodies (ADA) against the first TNF inhibitor influences the outcome after switching. Our aim was to assess whether the response to a second anti-TNF drug is related to the previous development of ADA to the first anti-TNF drug SpA patients.

Methods

Forty-two SpA patients began a second anti-TNF drug after failing to respond to the first anti-TNF therapy. Clinical activity was assessed by the Ankylosing Spondylitis Disease Activity Score (ASDAS) at baseline (at the beginning of the first and second anti-TNF therapy) and at 6 months after switching. The drug and ADA levels were measured by ELISA before each administration.

Results

All patients were treated with anti-TNF drugs and mainly due to inefficacy were switched to a second anti-TNF drug. Eleven of 42 (26.2%) developed ADA during the first biologic treatment. At baseline, no differences in ASDAS were found in patients with or without ADA to the first anti-TNF drug (3.52 ± 1.03 without ADA vs. 3.14 ± 0.95 with ADA, p = 0.399) and to the second anti-TNF drug (3.36 ± 0.94 without ADA vs. 3.09 ± 0.91 with ADA, p = 0.466). At 6 months after switching, patients with previous ADA had lower disease activity (1.62 ± 0.93 with ADA vs. 2.79 ± 1.01 without ADA, p = 0.002) and most patients without ADA had high disease activity state by the ASDAS (25 out of 31 (80.6%) without ADA vs. 3 out of 11 (27.3%) with ADA, p = 0.002).

Conclusions

In SpA the failure to respond to the first anti-TNF drug due to the presence of ADA predicts a better clinical response to a second anti-TNF drug.

The utility of modeling and simulation approaches to evaluate immunogenicity effect on the therapeutic protein pharmacokinetics

While therapeutic proteins (TP), particularly recombinant human proteins and fully human monoclonal antibodies, are designed to have a low immunogenic potential in humans, a clinical immune response does sometimes occur and cannot be predicted from preclinical studies. Changes in TP pharmacokinetics may be perceived as an early indication of antibody formation and serve as a surrogate for later changes in efficacy and safety in individual subjects. Given the substantial increase in number of biological products, including biosimilars, there is an urgent need to quantitatively predict and quantify the immune response and any consequential changes in TP pharmacokinetics. The purpose of this communication is to review the utility of population-based modeling and simulation approaches developed to date for investigating the development of an immune response and assessing its impact on TP pharmacokinetics. Two examples of empirical modeling approaches for pharmacokinetic assessment are presented. The first example presents methods to analyze pharmacokinetic data in the presence of anti-drug antibody (ADA) and confirm the effect of immunogenicity on TP pharmacokinetics in early phases of drug development. The second example provides a framework to analyze pharmacokinetic data in the absence or with very low incidence of ADA and confirm with enough power the lack of an immunogenicity effect on TP pharmacokinetics in late phases of drug development. Finally, a theoretical mechanism-based modeling framework is presented to mathematically relate the complex interaction among TP, their targets, and ADA.

Immunogenicity to therapeutic proteins: impact on PK/PD and efficacy

The development of therapeutic proteins requires the understanding of the relationship between the dose, exposure, efficacy, and toxicity of these molecules. Several intrinsic and extrinsic factors contribute to the challenges for measuring therapeutic proteins in a precise and accurate manner. In addition, induction of an immune response to therapeutic protein results in additional complexities in the analysis of the pharmacokinetic profile, toxicity, safety, and efficacy of this class of molecules. Assessment of immunogenicity of therapeutic proteins is a required aspect of regulatory filings for a licensing application and for the safe and efficacious use of these compounds. A systematic strategy and well-defined criteria for measuring anti-drug antibodies (ADA) have been established, to a large extent, through coordinated efforts. These recommendations are based on risk assessment and include the determination of ADA content (concentration/titer), affinity, immunoglobulin isotype/subtype, and neutralization capacity. This manuscript reviews the requirements necessary for understanding the nature of an ADA response in order to discern the impact of immunogenicity on pharmacokinetics/pharmacodynamics and efficacy.

Appropriate infliximab infusion dosage and monitoring: results of a panel meeting of rheumatologists, dermatologists and gastroenterologists

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

Infliximab is an effective treatment for rheumatoid arthritis, ankylosing spondylitis, Crohn's disease (both adult and paediatric), ulcerative colitis, psoriatic arthritis and plaque psoriasis and national and international guidelines have been developed for each indication.

WHAT THIS STUDY ADDS

This study is the first study which compared current international, national and local guidelines from the medical specialties involved in the treatment with infliximab on the following topics: indication, dosage, synergy and monitoring of vital signs.

AIMS

Infliximab, an anti-TNF biologic agent, is currently indicated and reimbursed for rheumatoid arthritis, ankylosing spondylitis, Crohn's disease (both adult and paediatric), ulcerative colitis, psoriatic arthritis and plaque psoriasis. Development of national and international guidelines for rheumatology, gastroenterology and dermatology, was mostly based on clinical studies and expert opinion. The aim of this study was to compare available guidelines and local protocols for rheumatology, dermatology and gastroenterology, regarding dosage of infliximab, synergy of infliximab with concomitant medication and monitoring of vital signs during infliximab administration, for achieving optimal care.

METHODS

Current international, national and local guidelines on the use of infliximab were reviewed and compared, differences and shortcomings were identified, and optimal treatment schedules discussed during a meeting (July 2008) of clinical experts and researchers from three departments of a Dutch university hospital.

RESULTS

Recommended dosages of infliximab are not equal for different indications. Loss of response to infliximab is a common problem encountered within the three medical specialties, but indications for adjustments in treatment schedules are lacking in all of the guidelines. Monitoring of vital signs (blood pressure, pulse, temperature) during infusion with infliximab is common practice and recommended by some guidelines. Routine measurement of vital signs is not of any value in predicting or recognizing acute infusion reactions, in our experience, and this is confirmed by literature on inflammatory bowel disease.

CONCLUSION

Different indications encompass different dosing schedules. National and internal guidelines do not provide advice regarding loss of response. Routine measurement of vital signs during infusion is not valuable in detecting acute infusion reactions and should only be performed in case of an acute infusion reaction. These topics need to be studied in future studies and covered in future guidelines.

Treatment response, drug survival, and predictors thereof in 764 patients with psoriatic arthritis treated with anti-tumor necrosis factor α therapy: results from the nationwide Danish DANBIO registry

OBJECTIVE

To investigate disease activity, treatment response, and drug survival, and predictors thereof, among Danish patients with psoriatic arthritis (PsA) receiving their first treatment series with a tumor necrosis factor α (TNFα) inhibitor.

METHODS

Patients with PsA were identified from a prospective nationwide rheumatologic database, the Danish biologics registry DANBIO, using data registered from 2000-2009. Information was obtained on the patients' clinical response to anti-TNFα treatment (defined as achievement of the American College of Rheumatology 20% [ACR20], ACR50, and ACR70 improvement criteria or a European League Against Rheumatism [EULAR] good response at least once during the first 6 months of treatment) and duration and rate of drug adherence (referred to as drug survival), as well as predictors thereof.

RESULTS

Of 764 patients with PsA, 320 received adalimumab, 260 infliximab, and 184 etanercept. Median drug survival was 2.9 years, and 1-year and 2-year drug survival rates were 70% and 57%, respectively. Clinical parameters that showed improvement over 6 months were the C-reactive protein (CRP) level, Health Assessment Questionnaire score, and 28-joint Disease Activity Score. Male sex, CRP level >10 mg/liter, concomitant methotrexate use, and low patient health visual analog scale score at baseline were associated with longer drug survival. Improvement was achieved by 59%, 45%, 24%, and 54% of patients according to the ACR20, ACR50, ACR70 response criteria and EULAR good response, respectively. A CRP level >10 mg/liter was predictive of the improvement responses (odds ratio [OR] 2.6 for ACR20, OR 3.0 for ACR50, OR 3.6 for ACR70, and OR 2.2 for EULAR good response).

CONCLUSION

In these patients with PsA treated with their first TNFα inhibitor in clinical practice, high drug adherence and responder rates were observed. Moreover, increased levels of CRP at baseline were associated with both good treatment responses and continued treatment, which may be of clinical value in selecting the patients most likely to benefit from treatment with TNFα inhibitors.

Infliximab pharmacokinetics in inflammatory bowel disease patients

Infliximab, a chimeric monoclonal antibody, has profoundly modified the treatment of several inflammatory diseases, but no satisfactory description of its pharmacokinetics is available. The objective of this study is to describe the pharmacokinetics of infliximab and to explore the sources of its interindividual variability. Thirty-three chronic inflammatory bowel disease patients were studied. Infliximab serum concentrations, obtained during therapeutic drug monitoring, were analyzed using a population approach. Influence of sex, weight, age, concomitant immunosuppressive treatment, and development of antibodies toward infliximab (ATI) on pharmacokinetic parameters was investigated. A two-compartment model with first-order distribution and elimination constants allowed a satisfactory description of infliximab serum concentrations. Mean population distribution and elimination half-lives were 4.3 and 18.5 days, respectively. Weight and sex were found to significantly influence volume of distribution of the central compartment, which increased with weight and was higher in men. Clearance was 2.7 times higher, and elimination half-life was 34% lower in the presence of ATI. In two patients, an increase in infliximab dose or a decrease in dosing interval lead to a decrease in infliximab clearance toward its value in patients without ATI. Infliximab pharmacokinetics are similar to those of other monoclonal antibodies, notably with an elimination half-life of approximately 3 weeks. Both body weight and sex were found to influence infliximab pharmacokinetics, and its clearance increased thrice in the presence of ATI.

Maintenance of infliximab treatment in ankylosing spondylitis: results of a one-year randomized controlled trial comparing systematic versus on-demand treatment

OBJECTIVE

Continuous treatment with the anti-tumor necrosis factor alpha (anti-TNFalpha) antibody infliximab is efficacious in ankylosing spondylitis (AS), whereas treatment discontinuation results in disease relapse, with variable delay. This study was undertaken to compare the efficacy of continuous treatment with infliximab with that of a treatment regimen adapted to symptom recurrence. Methotrexate (MTX) in combination with infliximab was also tested.

METHODS

Patients with active AS were randomly assigned at week 0 to receive infliximab every 6 weeks (continuous treatment) or upon symptom recurrence (on-demand treatment), following infusions at weeks 4, 6, and 10. Patients in the on-demand group were randomly assigned to receive either MTX in combination with infliximab or infliximab alone. Patients were monitored for 1 year. The primary end point was the proportion of patients who met the ASsessment in AS International Working Group criteria for 20% improvement (ASAS20) at week 58.

RESULTS

Of 247 patients, 124 were assigned to receive infliximab every 6 weeks and 123 to receive on-demand treatment. Among the latter, 62 received MTX, and 61 received infliximab alone. A greater proportion of patients receiving infliximab every 6 weeks fulfilled ASAS20 response criteria at week 58 than did patients receiving on-demand treatment (75% versus 46%; P<0.0001). Patients in the continuous treatment group received more infliximab infusions after week 10 than did those in the on-demand group (mean+/-SD 5.8+/-2.2 versus 3.5+/-2; P<0.0001). Addition of MTX did not significantly affect the proportion of patients with an ASAS20 response at week 58, nor the number of infliximab infusions administered.

CONCLUSION

These findings indicate that continuous treatment of AS with infliximab is more efficacious than on-demand treatment, and that the addition of MTX to infliximab provides no significant benefit.

Decreased clinical response to infliximab in ankylosing spondylitis is correlated with anti-infliximab formation

OBJECTIVES

Correlation of serum trough infliximab levels and antibodies to infliximab (anti-infliximab) with clinical response in ankylosing spondylitis.

METHODS

In accordance with the international ASsessment in Ankylosing Spondylitis (ASAS) consensus statement, patients were treated with infliximab (5 mg/kg) every 6 weeks after a starting regimen. Preinfusion sera were collected at baseline, 24 and 54 weeks. At every visit, the 20% improvement response (ASAS-20) was assessed and laboratory tests performed.

RESULTS

24 of the 38 (63%) patients fulfilled ASAS-20 response criteria after 24 weeks of treatment and 21 (53%) after 54 weeks. After 54 weeks, 11 (29%) patients showed undetectable serum trough infliximab levels and detectable anti-infliximab; six of these patients developed an infusion reaction. Anti-infliximab was found significantly more often (p = 0.04) in ASAS-20 non-responders compared with responders at week 54. Serum trough infliximab levels were significantly (p<0.0001) lower in patients with (mean 0.02 mg/l) than in those without (12.7 mg/l) anti-infliximab.

CONCLUSIONS

In ankylosing spondylitis, high levels of serum trough infliximab correlated with a good clinical response. Detection of anti-infliximab within 54 weeks is associated with undetectable serum trough infliximab levels, reduced response to treatment and increased risk of developing an infusion reaction.