Anti-TNF-α biotherapies: perspectives for evidence-based personalized medicine

Comparison of Two Clinical Laboratory Assays for Measuring Serum Adalimumab and Antibodies to Adalimumab

BACKGROUND

Adalimumab is a fully human monoclonal antibody developed against tumor necrosis factor (TNF), used for the treatment of autoimmune and chronic inflammatory diseases. Immunogenicity to this drug may lead to therapeutic failure. Various laboratory assays are used for measuring serum adalimumab and anti-drug antibodies (ADA) to adalimumab, for therapeutic monitoring and evaluation of clinical non-responsiveness. This study compared the performance of 2 clinical assays used by different reference laboratories.

METHODS

In total, 120 residual clinical samples were tested at both laboratories. A sandwich ELISA for adalimumab detecting free drug and a bridging ELISA capable of detecting both free and bound ADA were performed at the Mayo Clinic. A functional cell-based reporter gene assay (RGA) was used at ARUP Laboratories for measuring bioactive serum drug concentrations, and neutralizing ADA.

RESULTS

Seventy-eight samples had measurable concentrations of adalimumab by both methods and yielded a correlation coefficient r = 0.93, slope = 0.886, and intercept = 0.950. Overall agreement of 92.5% was observed between the assays, with most discrepant drug results being attributed to a higher positivity rate with ELISA (8/9). One outlier positive with RGA and negative with ELISA was confirmed by LC-MS/MS to be attributed to infliximab. Overall agreement of 79.2% was observed between the ADA assays. Differences in ADA results may be due to the bridging ELISA detecting total ADA (free, drug-bound, neutralizing, and non-neutralizing), while RGA detects free, neutralizing ADA only.

CONCLUSIONS

Although the assays are fundamentally different, the results show significant concordance between the clinically validated tests performed in different laboratories.

Inappropriate treatment response to DMARDs: A pathway to difficult-to-treat rheumatoid arthritis

In recent years, difficult-to-treat rheumatoid arthritis (D2T RA) has attracted significant attention from rheumatologists due to its poor treatment response and the persistent symptoms or signs experienced by patients. The therapeutic demands of patients with D2T RA are not properly met due to unclear pathogenic causes and a lack of high-quality data for current treatment options, creating considerable management difficulties with this patient population. This review describes the clinical challenges associated with disease-modifying antirheumatic drugs (DMARDs) and explores contributing factors associated with inappropriate response to DMARDs that may lead to D2T RA and related immunological dysregulation. It is now understood that D2T RA is a highly heterogeneous pathological status that involves multiple factors. These factors include but are not limited to genetics, environment, immunogenicity, comorbidities, adverse drug reactions, inappropriate drug application, poor adherence, and socioeconomic status. Besides, these factors may manifest in the selection and utilization of specific DMARDs, either individually or in combination, thereby contributing to inadequate treatment response. Finding these variables may offer hints for enhancing DMARD therapy plans and bettering the condition of D2T RA patients.

Baicalin Ameliorates Collagen-Induced Arthritis Through the Suppression of Janus Kinase 1 (JAK1)/Signal Transducer and Activator of Transcription 3 (STAT3) Signaling in Mice

Background

Rheumatoid arthritis is an autoimmune disease that causes chronic joint inflammation and there is no cure. Baicalin, as an ingredient in the roots of Scutellaria baicalensis, is supposed to possess an anti-inflammatory effect. However, the protective effect of baicalin on collagen-induced arthritis requires further investigation.

Material/Methods

A model of rheumatoid arthritis was established in 20 mice (8- to 10-weeks old). The mice were randomly divided into 2 groups after modeling and then injected with saline or baicalin, respectively. The synovial fluids and tissues were collected, and the pressure pain threshold and clinical arthritis score were measured. The levels of tumor necrosis factor (TNF)-α, interlukin-1β (IL-1β), IL-6, matrix metalloproteinases (MMP)-2, MMP-9, nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2) and their downstream inflammatory mediators Janus kinase 1 (JAK1)/signal transducer and activator of transcription 3 (STAT3), extracellular signal-regulated kinases 1/2 (ERK1/2), p38, Jun N-terminal kinases (JNK) activation were detected using enzyme-linked immunosorbent assay (ELISA), and western blotting analyses. The mononuclear cells apoptosis ratio was calculated by flowcytometry analyses.

Results

Baicalin significantly reduced disease activities in a rheumatoid arthritis mouse model, which were reflected by pressure pain thresholds and clinical arthritis scores. Relevant proinflammatory cytokines such as TNF-α, IL-1β, IL-6, gelatinases (MMP-2, MMP-9) and inducible enzymes (iNOS, COX-2) were generally suppressed. Moreover, baicalin treatment induced cells apoptosis in synovial fluid monocytes and markedly down regulated JAK1/STAT3 but not mitogen-activated protein kinases (MAPKs) expressions in synovium of arthritis.

Conclusions

These observations confirm the relief of rheumatoid arthritis by baicalin. Our results indicate the effect is related with the modulation of decreased proinflammatory cytokines and inflammatory markers. And the apoptosis promotion of monocytes in synovial fluid were also inhibited. Moreover, the molecular mechanism implies suppressed JAK1/STAT3 signaling with baicalin treatment.

Demystifying biosimilars: development, regulation and clinical use

Biologics are an integral component in the treatment of various diseases. However, limited patient access to these medicines remains a significant global challenge, prompting development of safe and effective biosimilars. A biosimilar is 'highly similar to a reference (originator) product, for which there are no clinically meaningful differences between the two products in terms of safety, purity and potency'. Biosimilars have the potential to offer possible benefits, including lower treatment costs, thereby increasing patient access and clinical use, which may lead to better overall outcomes. Improved understanding of biosimilars may enhance confidence and trust in these agents. As increasing numbers of biosimilars achieve regulatory approval, this overview aims to address enduring knowledge gaps regarding the development and use of biosimilars.

Secondary failure of TNF-α inhibitors in clinical practice

Tumor necrosis factor alpha (TNF-α) is a leading inflammatory cytokine that plays a pivotal role in the pathogenesis of psoriasis. In case of a severe course of psoriasis and moderate-to-severe disease in which traditional systemic treatments are ineffective or contraindicated, TNF-α inhibitors (iTNF-α) are used. This class of drugs includes monoclonal antibodies and a fusion protein (etanercept) and can induce a humoral or cell-mediated immune response, leading to formation of anti-drug antibodies (ADAs). The immunogenicity may affect iTNF-α drug pharmacokinetics, which would lead to hampering the clinical response (secondary drug failure), so a need to increase the drug dose arises. Antibodies against monoclonal antibodies (adalimumab, infliximab) have been associated with diminished clinical response, while against etanercept are non-neutralizing and appear to have no significant effect on clinical response and treatment safety. Switching of biologic agents may be one strategy in ADA-associated secondary failure of iTNF-α. However researches are needed to identify risk factors for ADA development and investigate management strategies for optimized treatment response. The authors reviewed the literature on the effectiveness of iTNF-α and pointed out the prevention of secondary failure in clinical practice.

Design of Mannose-Functionalized Curdlan Nanoparticles for Macrophage-Targeted siRNA Delivery

6-Amino-6-deoxy-curdlan is a promising nucleic acid carrier that efficiently delivers plasmid DNA as well as short interfering RNA (siRNA) to various cell lines. The highly reactive C6-NH₂ groups of 6-amino-6-deoxy-curdlan prompt conjugation of various side groups including tissue-targeting ligands to enhance cell-type-specific nucleic acid delivery to specific cell lines. Herein, to test the primary-cell-targeting efficiency of the curdlan derivative, we chemically conjugated a macrophage-targeting ligand, mannose, to 6-amino-6-deoxy-curdlan. The resulting curdlan derivative (denoted CMI) readily complexed with siRNA and formed nanoparticles with a diameter of 50-80 nm. The CMI nanoparticles successfully delivered a dye-labeled siRNA to mouse peritoneal macrophages. The delivery efficiency was blocked by mannan, a natural ligand for a macrophage surface mannose receptor (CD206), but not by zymosan, a ligand for the dectin-1 receptor, which is also present on the surface of macrophages. Moreover, CMI nanoparticles were internalized by macrophages only at 37 °C, suggesting that the cellular uptake of CMI nanoparticles was energy-dependent. Furthermore, CMI nanoparticle efficiently delivered siRNA against tumor necrosis factor α (TNFα) to lipopolysaccharide-stimulated primary mouse peritoneal macrophages. In vivo experiments demonstrated that CMI nanoparticles successfully delivered siTNFα to mouse peritoneal macrophages, liver, and lung and induced significant knockdown of the TNFα expression at both messenger RNA and protein levels. Therefore, our design of CMI may be a promising siRNA carrier for targeting CD206-expressing primary cells such as macrophage and dendritic cells.

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.

TNF-α level affects etanercept clearance: TNF-α concentration as a new correction factor of allometric scaling to predict individual etanercept clearances in patients with ankylosing spondylitis

Etanercept (ETN) is a widely used anti-tumour necrosis factor-α (TNF-α) agent, which relieves the symptoms of ankylosing spondylitis (AS) by binding to TNF-α to inhibit its inflammation effects. In this study, the effect of TNF-α level on ETN clearance (CL) was investigated, and the TNF-α concentration was initially set as a correction factor for allometric scaling to improve the predictions of individual ETN CLs. Individual ETN CLs and TNF-α concentrations in healthy volunteers and patients with AS were determined by performing ETN pharmacokinetic studies in the two cohorts. Accordingly, individual ETN CLs in both healthy volunteers and patients with AS were predicted from data of two animal species using different methods, including simple allometric scaling, scaling with a correction factor of maximum life span potential or brain weight, and scaling with a correction factor of the TNF-α concentration. The accuracies of such predictions were evaluated by the percentage errors. Consequently, increased TNF-α concentration was shown to improve ETN CL, by comparing both ETN CLs and TNF-α concentrations between healthy volunteers and patients with AS. More importantly, better predictions of individual ETN CLs were achieved in patients with AS using allometric scaling with TNF-α concentration as the correction factor. In conclusion, in vivo levels of TNF-α can affect ETN CL, and allometric scaling corrected with the TNF-α concentration can be used to estimate the individual CLs of anti-TNF-α monoclonal antibodies based on preclinical data.

Evaluation of the Cross-reactivity of Antidrug Antibodies to CT-P13 and Infliximab Reference Product (Remicade): An Analysis Using Immunoassays Tagged with Both Agents

Background

During two pivotal clinical trials of the infliximab biosimilar CT-P13 (PLANETAS and PLANETRA), antidrug antibodies (ADAs) and neutralising antibodies (NAbs) were detected in the sera of patients treated with CT-P13 and the reference product (RP; Remicade).

Objective

The aim was to assess the comparability of Remicade- and CT-P13-tagged immunoassays for the detection of ADAs and NAbs using data from these trials, in order to determine the cross-reactivity of CT-P13 and RP ADAs.

Methods

Sera from patients with rheumatoid arthritis and ankylosing spondylitis were analysed using an electrochemiluminescence (ECL) bridging assay or Gyros immunoassay, tagged with Remicade or CT-P13 at screening, weeks 14, 30 and 54, and the end of study visit. NAb titre was compared at screening and weeks 14 and 30. The proportion of cross-reactive samples was determined and an inter-rater agreement analysis performed to assess the concordance of results between assays.

Results

In PLANETAS, 93.1% (94/101) of RP ADA-positive samples and 93.0% (93/100) of RP NAb-positive samples cross-reacted with CT-P13; 99.0% (103/104) of CT-P13 ADA-positive and 98.0% (98/100) of CT-P13 NAb-positive samples cross-reacted with the RP. In PLANETRA, 94.7% (426/450) of RP ADA-positive samples and 94.3% (415/440) of RP NAb-positive samples cross-reacted with CT-P13, and 96.6% (458/474) of CT-P13 ADA-positive and 96.4% (452/469) of CT-P13 NAb-positive samples cross-reacted with the RP. In both studies, there was strong agreement in outcome between assays at all post-screening time points (PLANETAS: Cohen’s κ 0.89–0.98 for ADA, 0.86–0.98 for NAb; PLANETRA: 0.92–0.94 for both ADA and NAb, all p < 0.001). Significant concordance between assays was observed for NAb titre at weeks 14 and 30 (PLANETAS: Spearman’s ρ 0.73 and 0.74, respectively; PLANETRA: 0.61 and 0.72, respectively; all p < 0.001).

Conclusions

This study has demonstrated that ADAs and NAbs against CT-P13 and RP are cross-reactive, indicating that CT-P13 and RP share immunodominant epitopes.

Electronic supplementary material

The online version of this article (doi:10.1007/s40259-017-0219-4) contains supplementary material, which is available to authorized users.

The Role of Rituximab in Chronic Lymphocytic Leukemia Treatment and the Potential Utility of Biosimilars

Chronic lymphocytic leukemia (CLL) is managed with observation for asymptomatic or clinically silent disease; pharmacologic intervention is generally required for symptomatic patients with clinically significant adenopathy or cytopenia. In the front-line treatment of CLL, the current standard-of-care includes chemotherapy in combination with an anti-CD20 monoclonal antibody (e.g., rituximab, ofatumumab, or obinutuzumab) or ibrutinib as single agent. Despite the evolving treatment paradigm toward targeted therapy, it is likely that rituximab (plus chemotherapy), with or without targeted agents, will retain a significant role in CLL treatment. However, patents for many biologics, including rituximab, have expired or will expire in the near future. Furthermore, access to rituximab has remained challenging, particularly in countries with restricted resources. Together, these concerns have prompted the development of safe and effective rituximab biosimilars. The term "biosimilar" refers to a biologic that is highly similar to an approved reference (originator) product, notwithstanding minor differences in clinically inactive components, and for which there are no clinically meaningful differences in purity, potency, or safety. Biosimilars are developed to treat the same condition(s) using the same treatment regimens as an approved reference biologic and have the potential to increase access to more affordable treatments. We review the importance of rituximab in the current treatment of CLL, the scientific basis of its future role in combination with chemotherapy, and the role of new and emerging agents in the treatment of CLL, which could potentially be used in combination with rituximab biosimilars. We also discuss rituximab biosimilars currently in development.

IMPLICATIONS FOR PRACTICE

Front-line treatments for chronic lymphocytic leukemia (CLL) include chemotherapy in combination with an anti-CD20 monoclonal antibody (e.g., rituximab, ofatumumab, or obinutuzumab) or ibrutinib as single agent. Despite the evolving treatment paradigm, it is likely rituximab (plus chemotherapy) and targeted agents undergoing clinical evaluation will retain a significant role in CLL treatment. However, patents for many biologics, including rituximab, have expired or will expire in the near future and, in many regions, access to rituximab remains challenging. Together, these concerns have prompted the development of safe and effective rituximab biosimilars, with the potential to increase access to more affordable treatments.

Clinical effectiveness and cost-effectiveness of use of therapeutic monitoring of tumour necrosis factor alpha (TNF-α) inhibitors [LISA-TRACKER® enzyme-linked immunosorbent assay (ELISA) kits, TNF-α-Blocker ELISA kits and Promonitor® ELISA kits] versus standard care in patients with Crohn's disease: systematic reviews and economic modelling

BACKGROUND AND OBJECTIVES

Systematic reviews and economic modelling of clinical effectiveness and cost-effectiveness of therapeutic monitoring of tumour necrosis factor alpha (TNF-α) inhibitors [using LISA-TRACKER^® enzyme-linked immunosorbent assay (ELISA) kits (Theradiag, Marne La Vallee, France, or Alpha Laboratories, Heriot, UK), TNF-α-Blocker ELISA kits (Immundiagnostik AG, Bensheim, Germany) and Promonitor^® ELISA kits (Proteomika, Progenika Biopharma, Bizkaia, Spain)] versus standard care for Crohn's disease (CD).

METHODS

Multiple electronic databases were searched from inception to December 2014 in order to identify primary studies and meta-analyses.

POPULATION

Patients with moderate to severe active CD treated with infliximab (IFX) (Remicade^®, Merck Sharp & Dohme Ltd, Kenilworth, NJ, USA) or adalimumab (ADA) (Humira^®, AbbVie Inc., North Chicago, IL, USA).

INTERVENTION

Monitoring of serum anti-TNF-α (IFX or ADA) and/or of anti-drug antibody levels using test assays with a test-treatment algorithm.

COMPARATOR

Standard care.

OUTCOMES

Any patient-related outcome, test agreement and cost-effectiveness estimates. The quality assessments used recognised checklists (Quality Assessment of Diagnostic Accuracy Studies-2, Cochrane, Philips and Consolidated Health Economic Evaluation Reporting Standards). Evidence was synthesised using narrative review and meta-analysis. A Markov model was built in TreeAge Pro 2013 (TreeAge Software, Inc., Williamstown, MA, USA). The model had a 4-week cycle and a 10-year time horizon, adopted a NHS and Personal Social Services perspective and used a linked evidence approach. Costs were adjusted to 2013/14 prices and discounted at 3.5%.

RESULTS

We included 68 out of 2434 and 4 out of 2466 studies for the clinical effectiveness and cost-effectiveness reviews, respectively. Twenty-three studies comparing test methods were identified. Evidence on test concordance was sparse and contradictory, offering scant data for a linked evidence approach. Three studies [two randomised controlled trials (RCTs) and one retrospective observational study] investigated outcomes following implementation of a test algorithm. None used the specified commercial ELISA immunoassay test kits. Neither of the two RCTs demonstrated clinical benefit of a test-treatment regimen. A meta-analysis of 31 studies to estimate test accuracy for predicting clinical status indicated that 20-30% of test results are likely to be inaccurate. The four cost-effectiveness studies suggested that testing results in small cost reductions. In the economic analysis the base-case analysis showed that standard practice (no testing/therapeutic monitoring with the intervention tests) was more costly and more effective than testing for IFX. Sensitivity and scenario analyses gave similar results. The probabilistic sensitivity analysis indicated a 92% likelihood that the 'no-testing' strategy was cost-effective at a willingness to pay of £20,000 per quality-adjusted life-year.

STRENGTHS AND LIMITATIONS

Rigorous systematic reviews were undertaken; however, the underlying evidence base was poor or lacking. There was uncertainty about a linked evidence approach and a lack of gold standard for assay comparison. The only comparative evidence available for economic evaluation was for assays other than the intervention assays.

CONCLUSIONS

Our finding that testing is not cost-effective for IFX should be viewed cautiously in view of the limited evidence. Clinicians should be mindful of variation in performance of different assays and of the absence of standardised approaches to patient assessment and treatment algorithms.

FUTURE WORK RECOMMENDATIONS

There is substantial variation in the underlying treatment pathways and uncertainty in the relative effectiveness of assay- and test-based treatment algorithms, which requires further investigation. There is very little research evidence on ADA or on drug monitoring in children with CD, and conclusions on cost-effectiveness could not be reached for these.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42014015278.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Biosimilars: Key regulatory considerations and similarity assessment tools

A biosimilar drug is defined in the US Food and Drug Administration (FDA) guidance document as a biopharmaceutical that is highly similar to an already licensed biologic product (referred to as the reference product) notwithstanding minor differences in clinically inactive components and for which there are no clinically meaningful differences in purity, potency, and safety between the two products. The development of biosimilars is a challenging, multistep process. Typically, the assessment of similarity involves comprehensive structural and functional characterization throughout the development of the biosimilar in an iterative manner and, if required by the local regulatory authority, an in vivo nonclinical evaluation, all conducted with direct comparison to the reference product. In addition, comparative clinical pharmacology studies are conducted with the reference product. The approval of biosimilars is highly regulated although varied across the globe in terms of nomenclature and the precise criteria for demonstrating similarity. Despite varied regulatory requirements, differences between the proposed biosimilar and the reference product must be supported by strong scientific evidence that these differences are not clinically meaningful. This review discusses the challenges faced by pharmaceutical companies in the development of biosimilars.

Outcomes After Primary Infliximab Treatment Failure in Inflammatory Bowel Disease

BACKGROUND

Primary infliximab treatment failure is common in patients with inflammatory bowel disease and represents a challenge to clinicians. Treatment options are limited. This study assessed the prognosis, defined as surgery-free survival, in patients with primary infliximab treatment failure as compared to patients without primary failure (initial responders). Furthermore, this study assessed the specter of medical therapies used after primary infliximab treatment failure along with treatment outcomes.

METHODS

Retrospective, observational, cohort study of patients with inflammatory bowel disease treated with infliximab as first-line anti-tumor necrosis factor treatment at a tertiary center. Primary infliximab treatment failure was defined as no clinical improvement during infliximab induction therapy resulting in discontinuation of infliximab therapy.

RESULTS

A total of 560 patients (Crohn's disease n = 353 and ulcerative colitis n = 207) were treated with infliximab. Among these, 81 (15%) had primary infliximab treatment failure after a median of 3 infusions (weeks 0, 2, and 6) (interquartile range 2-4). The median surgery-free survival was 196 days from first infusion. One year after primary infliximab treatment failure, the majority of patients (n = 51, 63%) had inflammatory bowel disease-related surgery (Crohn's disease n = 19, 58%; ulcerative colitis n = 32, 67%; P = 0.49). There was a markedly increased risk of surgery in patients with primary infliximab treatment failure as compared to initial responders: odds ratio 6.3 (3.8-10.6), P < 0.0001. Among 30 patients handled by medical therapies, 16 (53%) still had active disease 1 year after primary infliximab treatment failure.

CONCLUSIONS

Primary infliximab treatment failure is associated with poor outcome including high risk of surgery or sustained active disease despite medical interventions.

Mass Spectrometry Approaches for Identification and Quantitation of Therapeutic Monoclonal Antibodies in the Clinical Laboratory

Therapeutic monoclonal antibodies (MAbs) are an important class of drugs used to treat diseases ranging from autoimmune disorders to B cell lymphomas to other rare conditions thought to be untreatable in the past. Many advances have been made in the characterization of immunoglobulins as a result of pharmaceutical companies investing in technologies that allow them to better understand MAbs during the development phase. Mass spectrometry is one of the new advancements utilized extensively by pharma to analyze MAbs and is now beginning to be applied in the clinical laboratory setting. The rise in the use of therapeutic MAbs has opened up new challenges for the development of assays for monitoring this class of drugs. MAbs are larger and more complex than typical small-molecule therapeutic drugs routinely analyzed by mass spectrometry. In addition, they must be quantified in samples that contain endogenous immunoglobulins with nearly identical structures. In contrast to an enzyme-linked immunosorbent assay (ELISA) for quantifying MAbs, mass spectrometry-based assays do not rely on MAb-specific reagents such as recombinant antigens and/or anti-idiotypic antibodies, and time for development is usually shorter. Furthermore, using molecular mass as a measurement tool provides increased specificity since it is a first-order principle unique to each MAb. This enables rapid quantification of MAbs and multiplexing. This review describes how mass spectrometry can become an important tool for clinical chemists and especially immunologists, who are starting to develop assays for MAbs in the clinical laboratory and are considering mass spectrometry as a versatile platform for the task.

Will bevacizumab biosimilars impact the value of systemic therapy in gynecologic cancers?

OBJECTIVE

Bevacizumab is an important component in the treatment of various cancers, and despite guidelines recommending its use in both ovarian and cervical cancer, patient access to bevacizumab and other angiogenesis inhibitors is limited. Biosimilars are large, structurally complex molecules that are intended to be highly similar to, and treat the same condition(s) as, an existing licensed or approved (reference) biologic, with no clinically meaningful differences in purity, potency and safety. This article summarizes the role of bevacizumab in the treatment paradigm of ovarian and cervical cancer. We also discuss the potential role of biosimilars to bevacizumab, which may offer more affordable options in the future treatment of gynecologic cancers.

METHODS

Literature searches of PubMed and ClinicalTrials.gov databases were conducted. Regulatory and individual pharmaceutical company web pages were also reviewed. Search terms included "biosimilar" and "bevacizumab," and these were used to identify information regarding biosimilar development, reporting results of biosimilar studies or biosimilars in development.

RESULTS

At present, four bevacizumab biosimilar candidates are undergoing comparative clinical assessment, with the potential to increase access and offer efficiencies across healthcare systems.

CONCLUSIONS

It is anticipated that biologics such as bevacizumab will continue to play a key role in the treatment of an array of gynecologic cancers. Biosimilars to bevacizumab are currently in development and have the potential to increase access to medicines in a variety of settings, including gynecologic cancers.

Assessing the Immunogenicity of Biopharmaceuticals

Biopharmaceuticals have the potential to raise an immunogenic response in treated individuals, which may impact the efficacy and safety profile of these drugs. As a result, it is essential to evaluate immunogenicity throughout the different phases of the clinical development of a biopharmaceutical, including post-marketing surveillance. Although rigorous evaluation of biopharmaceutical immunogenicity is required by regulatory authorities, there is a lack of uniform standards for the type, quantity, and quality of evidence, and for guidance on experimental design for immunogenicity assays or criteria to compare immunogenicity of biopharmaceuticals. Moreover, substantial technological advances in methods to assess immune responses have yielded higher immunogenicity rates with modern assays, and limit comparison of immunogenicity of biopharmaceuticals outside of head-to-head clinical trials. Accordingly, research programs, regulatory agencies, and clinicians need to keep pace with continuously evolving analyses of immunogenicity. Here, we review factors associated with immunogenicity of biopharmaceuticals, potential clinical ramifications, and current regulatory guidance for evaluating immunogenicity, and discuss methods to assess immunogenicity in non-clinical and clinical studies. We also describe special considerations for evaluating the immunogenicity of biosimilar candidates.

Immunogenicity Assessment of Tumor Necrosis Factor Antagonists in the Clinical Laboratory

BACKGROUND

Tumor necrosis factor (TNF) antagonists are increasingly used for the treatment of inflammatory and autoimmune diseases. Immunogenicity of these drugs poses therapeutic challenges such as therapeutic failure and adverse effects in a number of patients. Evaluation of clinical nonresponsiveness includes laboratory testing for drug concentrations and detecting the presence of antidrug antibodies.

CONTENT

This review provides an overview of the immunogenicity of TNF antagonists and testing methodologies currently available for measuring antidrug antibody response, which decreases treatment efficacy and may result in therapeutic failure. This review summarizes methodologies such as binding assays, including ELISA and HPLC-based homogenous mobility shift assay, as well as functional cell-based assays such as reporter gene assay. Furthermore, based on the laboratory findings of testing for antidrug antibody response, as well as serum drug concentrations, an algorithm is provided for interpretation, based on the current available literature and guidelines, which may aid in determining optimal therapy after treatment failure.

SUMMARY

Laboratory testing methodologies for measuring serum concentrations of TNF inhibitors and antidrug antibodies are clinically available. These methods provide an evidence-based, personalized approach for the workup of patients showing treatment failure, which saves time and resources, and contributes to improved patient care.

Off-label use of tumour necrosis factor-alpha inhibitors and anakinra at an Australian tertiary hospital

BACKGROUND

Tumour necrosis factor-alpha inhibitors (anti-TNFα) and anakinra are monoclonal antibodies against pro-inflammatory cytokines overexpressed in many systemic inflammatory diseases. In Australia, they are registered for the treatment of several rheumatological, gastroenterological and dermatological indications. Despite increasing observational evidence for their use in off-label indications, there is a paucity of outcome research from the Australian hospital sector.

AIMS

To describe the off-label use of anti-TNFα and anakinra at a tertiary referral hospital in Queensland, Australia and consideration of a drug register to inform future clinical decision-making.

METHODS

We performed an in-depth retrospective chart audit of off-label treatment with anti-TNFα or anakinra at the Royal Brisbane and Women's Hospital from mid-2010 to mid-2014, linking demographic, phenotypic, pathology and outcome data with these drugs.

RESULTS

Off-label use was identified in 10 patients. The most frequent indications were sarcoidosis and dermatological conditions. Three patients required sequential therapy with a second anti-TNFα (total responses = 13). Complete response occurred in 46%, partial response in 38% and primary non-response in 8%. Response was unable to be determined in 8%. We recorded 14 adverse events (infections most common).

CONCLUSION

This study suggests that anti-TNFα may be beneficial for some off-label indications (e.g. sarcoidosis). However, the observational design of this study (and pre-existing research) limits the ability to infer causality and generalise results. We propose the creation of a mandatory drug register to monitor off-label use. Whilst comparative efficacy cannot be established without a matched placebo arm, a register would enable some reporting on effectiveness in rare diseases and identify infrequent but serious adverse events.

Optimizing Treatment with TNF Inhibitors in Inflammatory Bowel Disease by Monitoring Drug Levels and Antidrug Antibodies

BACKGROUND

Biological tumor necrosis factor (TNF) inhibitors have revolutionized the treatment of inflammatory bowel disease and redefined treatment goals to include mucosal healing. Clinicians are faced with challenges such as inadequate responses, treatment failures, side effects, and high drug costs. The objective is to review optimization of anti-TNF therapy by use of personalized treatment strategies based on circulating drug levels and antidrug antibodies (Abs), i.e. therapeutic drug monitoring (TDM). Furthermore, to outline TDM-related pitfalls and their prevention.

METHODS

Literature review.

RESULTS

Circulating anti-TNF drug trough level is a marker for the pharmacokinetics (PK) of TNF inhibitors. Because of a number of factors, including antidrug antibodies, PK varies between and within patients across time leading to variable clinical outcomes. Differences in intestinal inflammatory phenotype influencing the pharmacodynamic (PD) responses to TNF inhibitors also affect treatment outcomes. As an alternative to handling anti-TNF-treated patients by empiric strategies, TDM identifies underlying PK and PD-related reasons for treatment failure and aids decision making to secure optimal clinical and economic outcomes. Although promising, evidence does not the support use of TDM to counteract treatment failure in quiescent disease. Use of TDM is challenged by methodological biases, difficulties related to differentiation between PK and PD problems, and temporal biases due to lack of chronology between changes in PK versus symptomatic and objective disease activity manifestations. Biases can be accommodated by knowledgeable interpretation of results obtained by validated assays with clinically established thresholds, and by repeated assessments over time using complimentary techniques.

CONCLUSIONS

TDM-guided anti-TNF therapy at treatment failure has been brought from bench to bedside.

Time Course and Clinical Implications of Development of Antibodies Against Adalimumab in Patients With Inflammatory Bowel Disease

BACKGROUND

Antibodies (Abs) against adalimumab (ADL) have been associated with low ADL levels and treatment failure.

AIM

To characterize the temporal characteristics of anti-ADL Ab appearance and possible disappearance, and determine the clinical significance on drug efficacy and disease course.

METHODS

Cohort study including inflammatory bowel disease patients in whom anti-ADL Abs had been assessed by radioimmunoassay (RIA) and, in case of disappearance, by enzyme immunoassay, and functional reporter gene assay.

RESULTS

Anti-ADL Abs were evaluated in 133 serum samples from 72 patients. Seventeen patients (24%) tested positive after median of 194 days, interquartile range of 66 to 361. The proportion with anti-ADL Abs was 22% after 1 year, and 32% from 21 months onwards. Anti-ADL Abs generally persisted at repeat assessments during continued ADL therapy (n=8). Disappearance of anti-ADL Abs during therapy (n=3) was presumably caused by methodological biases due to detection of nonfunctional nonpersistent anti-ADL Abs by RIA, or false-negative measurement at reassessment by RIA and reporter gene assay. Anti-ADL Abs appeared pharmacologically active as judged by a median ADL concentration below limit of detection versus 7.4 μg/mL in anti-ADL Ab-negative samples (P<0.0001). Anti-ADL Abs associated with loss of response (odds ratio estimated 67, P<0.0001), and shorter treatment duration (P<0.0001).

CONCLUSIONS

Abs against ADL appear in approximately one fourth of inflammatory bowel disease patients with decreasing frequency over time and usually within 1 year of therapy. Anti-ADL Abs generally persist during continued ADL therapy, and are associated with elimination of drug and treatment failure. Therefore, ADL cessation should be considered when anti-ADL Abs are detected and supported by clinical observations.

Immunogenicity of anti-TNF biologic agents in the treatment of rheumatoid arthritis

INTRODUCTION

The use of biologic disease-modifying anti-rheumatic drugs (DMARDs), including therapeutic antibodies, antibody fragments and protein constructs that target key mediators in the pathophysiology of rheumatoid arthritis (RA), has improved the chance of achieving low disease activity and clinical remission. However, individual patients respond differently to biologic DMARD therapy, particularly the tumor necrosis factor (TNF) inhibitors.

AREAS COVERED

While the variation of clinical response may be related to pharmacogenetic and other unknown factors, immunogenicity associated with some of these agents may contribute in part to a lack of efficacy and immune-mediated side effects. Timely detection of immunogenicity may avoid continued administration of ineffective treatment, and reduce unnecessary risks and costs. Access to and appropriate implementation of clinically validated drug level assays is required.

EXPERT OPINION

There are currently no evidence-based recommendations to guide biologic therapy on the basis of drug level and immunogenicity testing but as more data become available and better tests are developed, a strategy of immunopharmacologic guidance to individualize treatment of RA will emerge. The potential benefits of this approach must be balanced against the costs of monitoring, and further research is required.

Effect of Infliximab Dose Increase in Rheumatoid Arthritis at Different Trough Concentrations: A Cohort Study in Clinical Practice Conditions

Background

Evidence supporting treatment intensification in rheumatoid arthritis (RA) is limited and controversial. We explored outcomes of infliximab dose increases and accounted for pre-existing trough levels in patients with active RA.

Methods

This study was a retrospective study of 42 RA patients who received increased infliximab following an insufficient response (DAS28 >3.2). Serum concentrations of infliximab and antibodies to infliximab (ATI) and DAS28 and EULAR clinical response parameters were recorded for 1 year. Analyses were performed in three patient groups that were defined by infliximab serum concentration prior to treatment enhancement: no detectable, low (<1.1 μg/mL) or high (≥1.1 μg/mL) drug levels.

Results

No circulating infliximab was detected in 20 patients (47.6%), but 13 (31%) and 9 (21.4%) patients exhibited low and high levels, respectively. ATI was only detected in patients with no detectable drug levels because the drug interferes with ELISA. DAS28 disease activity globally showed a modest improvement after dose escalation, but this improvement did not persist after 6 and 12 months. Infliximab serum levels increased significantly in the high group (p = 0.016), but no increase was achieved in the low and no detectable groups. The three study groups exhibited similar disease activity over time, and no improvement was observed in the non-responder EULAR rates.

Conclusion

These results suggest that the efficacy of an infliximab dose increase is limited, and the response is independent of the infliximab trough serum concentration that is achieved prior to escalation.

Individualized Therapy Is a Long-Term Cost-Effective Method Compared to Dose Intensification in Crohn's Disease Patients Failing Infliximab

BACKGROUND

In Crohn's disease patients failing infliximab therapy, interventions defined by an algorithm based on infliximab and anti-infliximab antibody measurements have proven more cost-effective than intensifying the infliximab regimen.

AIM

This study investigated long-term economic outcomes at the week 20 follow-up study visit and after 1 year. Clinical outcomes were assessed at week 20.

METHODS

Follow-up from a 12-week, single-blind, clinical trial where patients with infliximab treatment failure were randomized to infliximab intensification (5 mg/kg every 4 weeks) (n = 36), or algorithm-defined interventions (n = 33). Accumulated costs, expressed as mean costs per patient, were based on the Danish National Patient Registry.

RESULTS

At the scheduled week 20 follow-up study visit, response and remission rates were similar in all study subpopulations between patients treated by the algorithm or by infliximab intensification. However, the sum of healthcare costs related to Crohn's disease was substantially lower (31 %) for patients randomized to algorithm-based interventions than infliximab intensification in the intention-to-treat population: $11,940 versus $17,236; p = 0.005. For per-protocol patients (n = 55), costs at the week 20 follow-up visit were even lower (49 %) in the algorithm group: $8,742 versus $17,236; p = 0.002. Figures were similar for patients having completed the 12-week trial as per protocol (50 % reduction in costs) (n = 45). Among patients continuing the allocated study intervention throughout the entire 20-week follow-up period (n = 29), costs were reduced by 60 % in algorithm-treated patients: $7,056 versus $17,776; p < 0.001. Cost-reduction percentages remained stable throughout one year.

CONCLUSION

Economic benefit of algorithm-based interventions at infliximab failure is maintained throughout 1 year.

Immunogenicity of Anti-TNF-α Biotherapies: II. Clinical Relevance of Methods Used for Anti-Drug Antibody Detection

Immunogenicity of biopharmaceuticals is complex and influenced by both structural and pharmacological factors, and by patient-related conditions such as disease being treated, previous and concomitant therapies, and individual immune responsiveness. Essential for tailored therapeutic strategies based on immunopharmacological evidence from individual patients (personalized medicine) is the use of assays for anti-drug antibodies (ADA) that are accurate and relevant in the clinical setting. This paper discusses immunogenicity of genetically engineered immunoglobulins directed against tumor-necrosis factor-α (TNF). Emphasis will be on commonly used methods for detection of ADA in human serum including issues that question the clinical applicability of these methodologies. The use of dubious assays for ADA in a clinical context may not only contribute to confusion as to the importance of drug immunogenicity but may also prevent development of safe and cost-effective ways of using biological TNF-antagonists.

High-dose infliximab therapy in Crohn's disease: clinical experience, safety, and efficacy

BACKGROUND

Inadequate response to infliximab [IFX] therapy in Crohn's disease [CD] may necessitate dose intensification. We evaluated safety and efficacy of high-dose IFX [HD IFX] [greater than 10mg/kg every 8 weeks] in CD and characterized predictors of response to HD IFX intensification.

METHODS

Electronic medical records were queried for CD patients between 2010 and 2012 who received HD IFX and were reviewed for history, medications, laboratory data, efficacy, and safety.

RESULTS

In all, 86 patients received HD IFX for CD at doses between 10 and 22.5mg/kg every 4 to 7 weeks. In early HD IFX therapy [week 1-16], 25.8% and 59.1% experienced full and partial response, respectively. In later HD IFX therapy [week 38-100], 27.9% and 34.4% experienced full and partial response, respectively. Median serum IFX levels increased from 1.7 to 7.3 µ/mL [p = 0.017], and median C-reactive protein [CRP] values decreased from 20.5 at baseline to 4.7 mg/L after 16 weeks [p < 0.001]. Baseline CRP values were significantly elevated in the group that responded at 1-16 weeks compared with nonresponders [22.0 vs 3.5mg/L, p < 0.01]. HD IFX therapy was discontinued in 26% and 7.3% of patients for inadequate response and adverse events, respectively. Eleven cases of infection required hospitalization for a serious infection rate of 7.41 events per 100 patient-years.

CONCLUSIONS

HD IFX therapy may benefit CD patients who have failed standard doses of IFX. HD IFX therapy may be associated with more serious adverse events compared with standard dosing. Baseline CRP value may predict clinical response to HD IFX.

Antibodies to infliximab and adalimumab in patients with rheumatoid arthritis in clinical remission: a cross-sectional study

Objective. To investigate if antibodies towards biological TNF-α inhibitors (anti-TNFi Abs) are present in patients with rheumatoid arthritis (RA) in clinical remission and to relate any anti-TNFi Abs to circulating level of TNF-α inhibitor (TNFi). Methods. Patients with RA, treated with infliximab or adalimumab, and in clinical remission (DAS28(CRP) < 2.6) were included from 6 out-patient clinics. In blood samples, presence of anti-TNFi Abs was determined by radioimmunoassay, and concentration of bioactive TNFi was measured by a cell-based reporter gene assay. Results. Anti-TNFi Abs were present in 8/44 patients (18%) treated with infliximab and 1/49 patients (2%) treated with adalimumab (p = 0.012). In the former group, anti-TNFi Abs corresponded with low levels of TNFi (p = 0.048). Anti-TNFi Ab-positive patients had shorter disease duration at initiation of TNFi therapy (p = 0.023) but were similar for the rest of the compared parameters. Conclusions. In RA patients in clinical remission, anti-TNFi Abs occur frequently in patients treated with infliximab, while they occur rarely in patients treated with adalimumab. Presence of anti-infliximab Abs is accompanied by low or undetectable levels of infliximab. These data suggest that continued infliximab treatment may be redundant in a proportion of RA patients treated with infliximab and in clinical remission.

Role for therapeutic drug monitoring during induction therapy with TNF antagonists in IBD: evolution in the definition and management of primary nonresponse

: Primary nonresponse and primary nonremission are important limitations of tumor necrosis factor (TNF) antagonists, occurring in 10% to 40% and 50% to 80% of patients with inflammatory bowel disease, respectively. The magnitude of primary nonresponse differs between phase III clinical trials and cohort studies, indicating differences, e.g., in definition, patient population or blinding. The causes of nonresponse can be attributed to the drug (pharmacokinetics, immunogenicity), the patient (genetics, disease activity), the disease (type, location, severity), and/or the treatment strategy (dosing regimen, combination therapy). Primary nonresponse has been attributed to "non-TNF-driven disease" which is an overly simplified and potentially misleading approach to the problem. Many patients with primary nonresponse could successfully be treated with dose optimization during the induction phase or switching to another TNF antagonist. Therefore, primary nonresponse is frequently not a non-TNF-driven disease. Recent studies from rheumatoid arthritis and preliminary data from inflammatory bowel disease evaluating therapeutic drug monitoring have suggested that early measurement of drug and anti-drug antibody concentrations could help to define primary nonresponse and rationalize patient management of this problem. Moreover, a modeling approach including pharmacological parameters and patient-related covariants could potentially be predictive for response to the treatment. We describe an overview of this evolution in thinking, underpinned by previous findings, and assess the potential role of early measurement of drug and antidrug antibody concentrations in the definition and management of primary nonresponse.

Fc fusion as a platform technology: potential for modulating immunogenicity

The platform technology of fragment crystallizable (Fc) fusion, in which the Fc region of an antibody is genetically linked to an active protein drug, is among the most successful of a new generation of bioengineering strategies. Immunogenicity is a critical safety concern in the development of any protein therapeutic. While the therapeutic goal of generating Fc-fusion proteins has been to extend half-life, there is a critical mass of literature from immunology indicating that appropriate design of the Fc component has the potential to engage the immune system for product-specific outcomes. In the context of Fc-fusion therapeutics, a review of progress in understanding Fc biology suggests the prospect of engineering products that have an extended half-life and are able to modulate the immune system.

Mechanistic basis for functional promiscuity in the TNF and TNF receptor superfamilies: structure of the LIGHT:DcR3 assembly

LIGHT initiates intracellular signaling via engagement of the two TNF receptors, HVEM and LTβR. In humans, LIGHT is neutralized by DcR3, a unique soluble member of the TNFR superfamily, which tightly binds LIGHT and inhibits its interactions with HVEM and LTβR. DcR3 also neutralizes two other TNF ligands, FasL and TL1A. Due to its ability to neutralize three distinct different ligands, DcR3 contributes to a wide range of biological and pathological processes, including cancer and autoimmune diseases. However, the mechanisms that support the broad specificity of DcR3 remain to be fully defined. We report the structures of LIGHT and the LIGHT:DcR3 complex, which reveal the structural basis for the DcR3-mediated neutralization of LIGHT and afford insights into DcR3 function and binding promiscuity. Based on these structures, we designed LIGHT mutants with altered affinities for DcR3 and HVEM, which may represent mechanistically informative probe reagents.

Clinical implications of measuring drug and anti-drug antibodies by different assays when optimizing infliximab treatment failure in Crohn's disease: post hoc analysis of a randomized controlled trial

OBJECTIVES

Cost-effective guidance of therapeutic strategy in Crohn's disease patients with secondary infliximab (IFX) treatment failure may be achieved by serum IFX and anti-IFX antibody (Ab) measurements by radioimmunoassay (RIA). This study investigated implications of using other techniques for this purpose.

METHODS

This is a post hoc analysis of randomized clinical trial including 66 Crohn's disease patients with IFX failure in whom IFX and anti-IFX Ab measurements by RIA had been used for therapeutic guidance. Samples were additionally assessed by enzyme-linked immunosorbent assay (ELISA), homogeneous mobility shift assay (HMSA), and functional cell-based reporter gene assay (RGA).

RESULTS

IFX detection was comparable between assays (82% RIA, 76% ELISA, 88% HMSA, and 74% RGA), and it correlated significantly (Pearson's r=0.91-0.97, P<0.0001). However, IFX concentrations varied systematically between all pair of assays except RIA-RGA. Anti-IFX Ab detection was variable (27% RIA, 9% ELISA, 33% HMSA, and 11% RGA), but correlated significantly (Pearson's r=0.77-0.96; P<0.0001). Anti-IFX Abs detected by RIA and HMSA were often from sera without drug-neutralizing activity (RGA). Assays agreed on classification of underlying mechanism for treatment failure in most cases (79-94%). The majority (74-88%) failed IFX owing to pharmacodynamic problems, or had noninflammatory pathophysiology for symptoms resembling relapse. Applied threshold for therapeutic vs. subtherapeutic IFX level influenced classifications. The four different assays did not differ in terms of the ability to predict response to interventions defined by the algorithm.

CONCLUSIONS

Despite variable analytical properties, common assays result in similar classifications and interventions in patients with IFX treatment failure, and with comparable clinical outcomes. Implications are, however, profound for the minority classified differently.

A development that may evolve into a revolution in medicine: mRNA as the basis for novel, nucleotide-based vaccines and drugs

Recent advances strongly suggest that mRNA rather than DNA will be the nucleotide basis for a new class of vaccines and drugs. Therapeutic cancer vaccines against a variety of targets have been developed on this basis and initial clinical experience suggests that preclinical activity can be successfully translated to human application. Likewise, prophylactic vaccines against viral pathogens and allergens have demonstrated their activity in animal models. These successes could be extended preclinically to mRNA protein and gene replacement therapy as well as the induction of pluripotent stem cells by mRNA encoded transcription factors. The production of mRNA-based vaccines and drugs is highly flexible, scalable and cost competitive, and eliminates the requirement of a cold chain. mRNA-based drugs and vaccines offer all the advantages of a nucleotide-based approach at reduced costs and represent a truly disruptive technology that may start a revolution in medicine.

Individualised therapy is more cost-effective than dose intensification in patients with Crohn's disease who lose response to anti-TNF treatment: a randomised, controlled trial

OBJECTIVE

Although the reasons for secondary loss of response to infliximab (IFX) maintenance therapy in Crohn's disease vary, dose intensification is usually recommended. This study investigated the cost-effectiveness of interventions defined by an algorithm designed to identify specific reasons for therapeutic failure.

DESIGN

Randomised, controlled, single-blind, multicentre study. 69 patients with secondary IFX failure were randomised to IFX dose intensification (5 mg/kg every 4 weeks) (n=36) or interventions based on serum IFX and IFX antibody levels using the proposed algorithm (n=33). Predefined co-primary end points at week 12 were proportion of patients responding (Crohn's Disease Activity Index (CDAI) decrease ≥ 70, or ≥ 50% reduction in active fistulas) and accumulated costs related to treatment of Crohn's disease, expressed as mean cost per patient, based on the Danish National Patient Registry for all hospitalisation and outpatient costs in the Danish healthcare sector.

RESULTS

Costs for intention-to-treat patients were substantially lower (34%) for those treated in accordance with the algorithm than by IFX dose intensification: € 6038 vs € 9178, p<0.001. However, disease control, as judged by response rates, was similar: 58% and 53%, respectively, p=0.81; difference 5% (-19% to 28%). For per-protocol patients, treatment costs were even lower (56%) in the algorithm-treated group (€ 4062 vs € 9178, p<0.001) and with similar response rates (47% vs 53%, p=0.78; difference -5% (-33% to 22%)).

CONCLUSIONS

Treatment of secondary IFX failure using an algorithm based on combined IFX and IFX antibody measurements significantly reduces average treatment costs per patient compared with routine IFX dose escalation and without any apparent negative effect on clinical efficacy.

TRIAL REGISTRATION NO

NCT00851565.

Immunogenicity and PK/PD evaluation in biotherapeutic drug development: scientific considerations for bioanalytical methods and data analysis

With the advent of novel technologies, considerable advances have been made in the evaluation of the relationship between PK and PD. Ligand-binding assays have been the primary assay format supporting PK and immunogenicity assessments. Critical and in-depth characterizations of the ligand-binding assay of interest can provide valuable understanding of the limitations, for interpreting PK/PD and immunogenicity results. This review illustrates key challenges with regard to understanding the relationship between anti-drug antibody and PK/PD, including confounding factors associated with the development and validation of ligand-binding assays, mechanisms by which anti-drug antibody impacts PK/PD, factors to consider during data analyses and interpretation, and a perspective on integrating immunogenicity data into the well-established quantitative modeling approach. Through recognizing these challenges, we propose some opportunities for improvements in the development and validation of fit-for-purpose bioanalytical methods.

Neutralization of leukotriene C4 and D4 activity by monoclonal and single-chain antibodies

BACKGROUND

Cysteinyl leukotrienes (LTs) are key mediators in inflammation. To explore the structure of the antigen-recognition site of a monoclonal antibody against LTC4 (mAbLTC), we previously isolated full-length cDNAs for heavy and light chains of the antibody and prepared a single-chain antibody comprising variable regions of these two chains (scFvLTC).

METHODS

We examined whether mAbLTC and scFvLTC neutralized the biological activities of LTC4 and LTD4 by competing their binding to their receptors.

RESULTS

mAbLTC and scFvLTC inhibited their binding of LTC4 or LTD4 to CysLT1 receptor (CysLT1R) and CysLT2 receptor (CysLT2R) overexpressed in Chinese hamster ovary cells. The induction by LTD4 of monocyte chemoattractant protein-1 and interleukin-8 mRNAs in human monocytic leukemia THP-1 cells expressing CysLT1R was dose-dependently suppressed not only by mAbLTC but also by scFvLTC. LTC4- and LTD4-induced aggregation of mouse platelets expressing CysLT2R was dose-dependently suppressed by either mAbLTC or scFvLTC. Administration of mAbLTC reduced pulmonary eosinophil infiltration and goblet cell hyperplasia observed in a murine model of asthma. Furthermore, mAbLTC bound to CysLT2R antagonists but not to CysLT1R antagonists.

CONCLUSIONS

These results indicate that mAbLTC and scFvLTC neutralize the biological activities of LTs by competing their binding to CysLT1R and CysLT2R. Furthermore, the binding of cysteinyl LT receptor antagonists to mAbLTC suggests the structural resemblance of the LT-recognition site of the antibody to that of these receptors.

GENERAL SIGNIFICANCE

mAbLTC can be used in the treatment of inflammatory diseases such as asthma.

Review article: immunogenicity of anti-TNF biologics in IBD - the role of patient, product and prescriber factors

BACKGROUND

Anti-drug antibodies (ADAs) to biologic therapies contribute to the loss of response and infusion reactions to anti-TNF drugs in patients with inflammatory bowel disease (IBD). The reasons behind this immunogenicity are complex, and have not been the focus of a dedicated review for prescribers.

AIM

To provide an overview of the patient, product and prescriber factors, which have been associated with the immunogenicity of anti-TNF therapy, and draw conclusions for clinical practice.

METHODS

Review of representative observational studies and clinical trials from the IBD and other literature, which report associations with ADA development, with a focus on infliximab and adalimumab.

RESULTS

ADAs develop in 10-20% of patients receiving anti-TNF maintenance therapy, and these patients are three times more likely to lose response as ADA-negative patients. Patient genotype plays a role in ADA risk in a minority of patients, but age or disease type is not a major factor. Drug mishandling, such as agitation or freeze-thaw cycles, can induce protein aggregates, which are known to be immunogenic. Prescription of maintenance therapy with concomitant immunomodulators, and achieving suitable trough drug levels, reduces the risk of ADAs in patients with IBD.

CONCLUSIONS

Patients and prescribers can take several steps to reduce the risk of development of anti-drug antibodies to anti-TNF antibodies. Further research is required to determine if immunogenic factors identified in other situations apply to use of anti-TNFs in IBD.

Downregulation of pro-inflammatory mediators by a water extract of Schisandra chinensis (Turcz.) Baill fruit in lipopolysaccharide-stimulated RAW 264.7 macrophage cells

Schisandra chinensis has a long-standing history of medicinal use as a tonic, a sedative, an anti-tussive, and an anti-aging drug. Nevertheless, the antagonistic effects of S. chinensis against lipopolysaccharide (LPS)-stimulated responses have not yet been studied. In this study, we investigated whether water extract of S. chinensis fruit (WESC) has the ability to attenuate the expression of pro-inflammatory mediators such as nitric oxide (NO), prostaglandin E2 (PGE2), and tumor necrosis factor-α (TNF-α) in LPS-stimulated RAW 264.7 macrophage cells. WESC inhibited the expression of LPS-induced pro-inflammatory mediators, namely, NO, PGE2, and TNF-α. Furthermore, gene expression of inducible NO synthase (iNOS), cyclooxygenase-2 (COX-2), and TNF-α was inhibited both at mRNA and protein synthesis levels, without any cytotoxic effect. Moreover, WESC significantly suppressed LPS-induced DNA-binding activity of NF-κB by inhibiting degradation of IκBα. It was found that pyrrolidine dithiocarbamate (PDTC), a specific NF-κB inhibitor, downregulates the expression of these pro-inflammatory genes to be closely regulated by NF-κB activity. Furthermore, we found that WESC retains dephosphorylation of Akt in response to LPS, and consequently suppressed the DNA-binding activity of NF-κB in RAW 264.7 macrophage cells. LY294002, a specific Akt inhibitor, attenuated LPS-induced pro-inflammatory gene expression via suppression of NF-κB activity. Taken together, our results indicate that WESC downregulates the expression of pro-inflammatory genes involved in the synthesis of NO, PGE2, and TNF-α in LPS-stimulated RAW 264.7 macrophage cells by suppressing Akt-dependent NF-κB activity.