Developing the next generation of monoclonal antibodies for the treatment of rheumatoid arthritis

Toward Overcoming Treatment Failure in Rheumatoid Arthritis

Rheumatoid arthritis (RA) is an autoimmune disorder characterized by inflammation and bone erosion. The exact mechanism of RA is still unknown, but various immune cytokines, signaling pathways and effector cells are involved. Disease-modifying antirheumatic drugs (DMARDs) are commonly used in RA treatment and classified into different categories. Nevertheless, RA treatment is based on a "trial-and-error" approach, and a substantial proportion of patients show failed therapy for each DMARD. Over the past decades, great efforts have been made to overcome treatment failure, including identification of biomarkers, exploration of the reasons for loss of efficacy, development of sequential or combinational DMARDs strategies and approval of new DMARDs. Here, we summarize these efforts, which would provide valuable insights for accurate RA clinical medication. While gratifying, researchers realize that these efforts are still far from enough to recommend specific DMARDs for individual patients. Precision medicine is an emerging medical model that proposes a highly individualized and tailored approach for disease management. In this review, we also discuss the potential of precision medicine for overcoming RA treatment failure, with the introduction of various cutting-edge technologies and big data.

Characterization of concurrent target suppression by JNJ-61178104, a bispecific antibody against human tumor necrosis factor and interleukin-17A

Tumor necrosis factor (TNF) and interleukin (IL)-17A are pleiotropic cytokines implicated in the pathogenesis of several autoimmune diseases including rheumatoid arthritis (RA) and psoriatic arthritis (PsA). JNJ-61178104 is a novel human anti-TNF and anti-IL-17A monovalent, bispecific antibody that binds to both human TNF and human IL-17A with high affinities and blocks the binding of TNF and IL-17A to their receptors in vitro. JNJ-61178104 also potently neutralizes TNF and IL-17A-mediated downstream effects in multiple cell-based assays. In vivo, treatment with JNJ-61178104 resulted in dose-dependent inhibition of cellular influx in a human IL-17A/TNF-induced murine lung neutrophilia model and the inhibitory effects of JNJ-61178104 were more potent than the treatment with bivalent parental anti-TNF or anti-IL-17A antibodies. JNJ-61178104 was shown to engage its targets, TNF and IL-17A, in systemic circulation measured as drug/target complex formation in normal cynomolgus monkeys (cyno). Surprisingly, quantitative target engagement assessment suggested lower apparent in vivo target-binding affinities for JNJ-61178104 compared to its bivalent parental antibodies, despite their similar in vitro target-binding affinities. The target engagement profiles of JNJ-61178104 in humans were in general agreement with the predicted profiles based on cyno data, suggesting similar differences in the apparent in vivo target-binding affinities. These findings show that in vivo target engagement of monovalent bispecific antibody does not necessarily recapitulate that of the molar-equivalent dose of its bivalent parental antibody. Our results also offer valuable insights into the understanding of the pharmacokinetics/pharmacodynamics and target engagement of other bispecific biologics against dimeric and/or trimeric soluble targets in vivo.

Tofacitinib in the treatment of moderate-to-severe rheumatoid arthritis: a cost-effectiveness analysis compared with adalimumab in Taiwan

Aims: Tofacitinib is an oral Janus kinase inhibitor for the treatment of rheumatoid arthritis (RA). This analysis investigated the cost-effectiveness of the second-line treatment with tofacitinib, compared with adalimumab, both plus methotrexate (MTX), in patients with moderate-to-severe RA and an inadequate response to the first-line MTX, from a Taiwan National Health Insurance Administration perspective. Materials and methods: A patient-level simulation model was used to project lifetime costs and quality-adjusted life-years (QALYs). Base-case analysis compared second-line treatment with tofacitinib 5 mg twice daily plus MTX vs adalimumab 40 mg every 2 weeks plus MTX. Patients switched or discontinued treatment due to a lack or loss of effectiveness or a serious adverse event. Efficacy was measured by change in Health Assessment Questionnaire-Disability Index (HAQ-DI) score. HAQ-DI scores were used to predict mortality and resource utilization, and were mapped onto utility values to estimate QALYs. Efficacy and safety data were derived from clinical trials and other secondary sources. Uncertainty in model parameters was explored using one-way deterministic and probabilistic sensitivity analyses. Results: Patients gained 0.09 more QALYs with second-line tofacitinib plus MTX compared with adalimumab plus MTX (5.13 vs 5.04, respectively) at an additional cost of New Taiwan Dollars (NT$) 12,881. The incremental cost-effectiveness ratio was NT$143,122/QALY. One-way sensitivity analysis confirmed the base-case result was robust. Limitations: The lack of available clinical data, particularly for HAQ-DI scores, may introduce some bias in the analysis. No patients were in an early stage of RA, which may limit the generalizability of these results. Base-case results from our study are not necessarily generalizable to countries with healthcare systems that differ considerably from Taiwan. Conclusions: From a payer perspective, second-line treatment with tofacitinib plus MTX is a cost-effective treatment strategy, compared with adalimumab plus MTX, in patients with moderate-to-severe RA in Taiwan.

Era of biosimilars in rheumatology: reshaping the healthcare environment

Compared with the original approved biological drug on which it is based, a biosimilar has highly similar physicochemical characteristics and biological activity, as well as equivalent efficacy and no clinically meaningful differences in safety and immunogenicity. Before they are approved, biosimilars must undergo a rigorous development process using state-of-the-art technologies to establish biosimilarity to the reference biological product. After approval, biosimilars must comply with good pharmacological practices for biological drugs. Several biosimilar disease-modifying antirheumatic drugs (bsDMARDs) based on the tumour necrosis factor inhibitors adalimumab, etanercept and infliximab have been approved for use in patients with rheumatic diseases. Substantial cost savings can be made if biological-naive patients begin treatment with bsDMARDs, and patients receiving original biological DMARDs (bDMARDs) are switched to bsDMARDs. Despite the consistently similar efficacy, safety and immunogenicity of bsDMARDs relative to their respective original bDMARDs, switching from a reference bDMARD to a bsDMARD can result in nocebo responses, such as subjective increase of disease activity and pain-related adverse events. This may have a negative impact on adherence to bsDMARDs in clinical trials and clinical practice. To ensure optimal and rational integration of bsDMARDs into rheumatology practice and realise the full cost-saving efficacy of these drugs, rheumatologists must be aware that careful communication of the cost-saving efficacy and safety of bsDMARDs to their patients is the key to a successful long-term switch to bsDMARD therapy.

Pharmacokinetics, Pharmacodynamics, Immunogenicity, Safety, and Tolerability of JNJ-61178104, a Novel Tumor Necrosis Factor-Alpha and Interleukin-17A Bispecific Antibody, in Healthy Subjects

The safety, tolerability, pharmacokinetics, pharmacodynamics, and immunogenicity of JNJ-61178104, a novel anti-tumor necrosis factor-alpha (TNFα) and anti-interleukin-17A (IL-17A) bispecific antibody, were investigated in a placebo-controlled, first-in-human study. Healthy subjects (n = 54) received a single dose of JNJ-61178104 by either intravenous infusion (0.1, 0.3, 1, 3, and 10 mg/kg) or subcutaneous injection (1 mg/kg). Blood samples for measurement of serum JNJ-61178104 concentrations, total IL-17A, total TNFα, and detection of antidrug antibodies were collected for up to 16 weeks after dosing and assessed using electrochemiluminescence immunoassays. PK parameters were calculated by noncompartmental analysis and estimated by nonlinear mixed-effects modeling. JNJ-61178104 was generally well tolerated in healthy subjects. For the intravenous cohorts, mean maximum concentration, and area under the concentration-time curve values increased in a dose-proportional manner. Mean clearance ranged from 6.73 to 9.99 mL/day/kg, mean volume of distribution at terminal phase after intravenous administration ranged from 51.0 to 91.9 mL/kg, and mean half-life ranged from 4.3 to 9.7 days following intravenous administration. After a single subcutaneous dose of 1 mg/kg, median time to maximum concentration was 4.0 days, mean bioavailability was 52.0% and mean half-life was 5.3 days. A linear 2-compartment population model with first-order elimination adequately characterized the pharmacokinetics with parameters consistent with noncompartmental analysis estimates. Body weight and antidrug antibodies were significant covariates on JNJ-61178104 clearance. The time to reach mean maximum serum total TNFα and total IL-17A concentrations appeared to be dose dependent across the 0.1 mg/kg to 10 mg/kg IV dose groups. All subjects who received active treatment were antidrug antibody positive after dosing with JNJ-61178104.

Endothelial Progenitor Cells: New Targets for Therapeutics for Inflammatory Conditions With High Cardiovascular Risk

Over the past decade, we have witnessed an exponential growth of interest into the role of endothelial progenitor cells (EPCs) in cardiovascular disease. While the major thinking revolves around EPC angiogenic repair properties, we have used a hypothesis-driven approach to discover disease-related defects in their characteristics and based on these findings, have identified opportunities for functional enhancement, which offer an exciting avenue for translation into clinical intervention. In this review, we focus on two groups; circulating myeloid angiogenic cells (MACs) and late outgrowth endothelial colony forming cells (ECFCs), and will discuss the unique properties and defects of each population, as new insights have been gained into the potential function of each sub-type using current techniques and multiomic technology. We will discuss their role in inflammatory disorders and alterations in mitochondrial function. In addition, we share key insights into the glycocalyx, and propose this network of membrane-bound proteoglycans and glycoproteins, covering the endothelium warrants further investigation in order to clarify its significance in ECFC regulation of vascularization and angiogenesis and ultimately for potential translational therapeutic aspects.

Disease modifying actions of interleukin-6 blockade in a rat model of bone cancer pain

Metastasis of cancer to the skeleton represents a debilitating turning point in the lives of patients. Skeletal metastasis leads to moderate to severe ongoing pain along with bone remodeling that can result in fracture, events that dramatically diminish quality of life. Interleukin-6 (IL-6) levels are elevated in patients with metastatic breast cancer and are associated with a lower survival rate. We therefore determined the consequences of inhibition of IL-6 signaling using a novel small molecule antagonist, TB-2-081, on bone integrity, tumor progression, and pain in a rodent model of breast cancer. Rat MAT B III mammary adenocarcinoma cells were injected and sealed within the tibia of female Fischer rats. Growth of these cells within the rat tibia elicited increased IL-6 levels both within the bone exudate and in the plasma, produced ongoing pain and evoked hypersensitivity, and bone fracture that was observed by approximately day 12. Systemic TB-2-081 delivered by subcutaneous osmotic minipumps starting at tumor implantation prevented tumor-induced ongoing bone pain and evoked hypersensitivity without altering tumor growth. Remarkably, TB-2-081 infusion significantly reduced osteolytic and osteoblastic bone remodeling and time to fracture likely by decreasing osteoclastogenesis and associated increase in bone resorption. These findings indicate that blockade of IL-6 signaling may represent a viable, disease-modifying strategy to prevent tumor-induced bone remodeling allowing for stabilization of bone and decreased fractures as well as diminished ongoing pain that may improve quality of life of patients with skeletal metastases. Notably, anti-IL-6 antibodies are clinically available allowing for rapid testing of these possibilities in humans.

Distance-Guided Forward and Backward Chain-Growth Monte Carlo Method for Conformational Sampling and Structural Prediction of Antibody CDR-H3 Loops

Antibodies recognize antigens through the complementary determining regions (CDR) formed by six-loop hypervariable regions crucial for the diversity of antigen specificities. Among the six CDR loops, the H3 loop is the most challenging to predict because of its much higher variation in sequence length and identity, resulting in much larger and complex structural space, compared to the other five loops. We developed a novel method based on a chain-growth sequential Monte Carlo method, called distance-guided sequential chain-growth Monte Carlo for H3 loops (DiSGro-H3). The new method samples protein chains in both forward and backward directions. It can efficiently generate low energy, near-native H3 loop structures using the conformation types predicted from the sequences of H3 loops. DiSGro-H3 performs significantly better than another ab initio method, RosettaAntibody, in both sampling and prediction, while taking less computational time. It performs comparably to template-based methods. As an ab initio method, DiSGro-H3 offers satisfactory accuracy while being able to predict any H3 loops without templates.

libFLASM: a software library for fixed-length approximate string matching

Background

Approximate string matching is the problem of finding all factors of a given text that are at a distance at most k from a given pattern. Fixed-length approximate string matching is the problem of finding all factors of a text of length n that are at a distance at most k from any factor of length ℓ of a pattern of length m. There exist bit-vector techniques to solve the fixed-length approximate string matching problem in time \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$\mathcal {O}(m\lceil \ell /w \rceil n)$\end{document}O(m⌈ℓ/w⌉n) and space \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$\mathcal {O}(m\lceil \ell /w\rceil)$\end{document}O(m⌈ℓ/w⌉) under the edit and Hamming distance models, where w is the size of the computer word; as such these techniques are independent of the distance threshold k or the alphabet size. Fixed-length approximate string matching is a generalisation of approximate string matching and, hence, has numerous direct applications in computational molecular biology and elsewhere.

Results

We present and make available libFLASM, a free open-source C++ software library for solving fixed-length approximate string matching under both the edit and the Hamming distance models. Moreover we describe how fixed-length approximate string matching is applied to solve real problems by incorporating libFLASM into established applications for multiple circular sequence alignment as well as single and structured motif extraction. Specifically, we describe how it can be used to improve the accuracy of multiple circular sequence alignment in terms of the inferred likelihood-based phylogenies; and we also describe how it is used to efficiently find motifs in molecular sequences representing regulatory or functional regions. The comparison of the performance of the library to other algorithms show how it is competitive, especially with increasing distance thresholds.

Conclusions

Fixed-length approximate string matching is a generalisation of the classic approximate string matching problem. We present libFLASM, a free open-source C++ software library for solving fixed-length approximate string matching. The extensive experimental results presented here suggest that other applications could benefit from using libFLASM, and thus further maintenance and development of libFLASM is desirable.

Safety and Efficacy of SBI-087, a Subcutaneous Agent for B Cell Depletion, in Patients with Active Rheumatoid Arthritis: Results from a Phase II Randomized, Double-blind, Placebo-controlled Study

OBJECTIVE

To evaluate subcutaneous SBI-087 to treat rheumatoid arthritis (RA).

METHODS

A total of 210 adult patients with active RA were randomized to receive either 200 mg SBI-087 or placebo (Pbo), according to one of these patterns: SBI/Pbo/Pbo (SBI on Day 1), SBI/SBI/Pbo (SBI days 1 and 15), SBI/Pbo/SBI (SBI days 1 and 84), SBI/SBI/SBI (SBI days 1, 15, and 84), or Pbo/Pbo/Pbo (Pbo all 3 days). All patients were seropositive and taking background methotrexate. The primary endpoint was proportion of patients achieving 20% improvement from baseline at Week 16 by American College of Rheumatology criteria (ACR20). Other outcomes included 28-joint Disease Activity Score (DAS28)-C-reactive protein (CRP), physician's and patient's global assessments of disease activity (PGA and PtGA, respectively) and Health Assessment Questionnaire-Disability Index (HAQ-DI). Peripheral CD19+ B cells were measured by high-sensitivity flow cytometer. Statistical significance was set at 2-sided α 0.10 level.

RESULTS

The SBI/SBI/SBI group demonstrated significant improvement in ACR20 and DAS28-CRP from Week 8 onward, sustained improvement in CRP levels from Week 12 onward, and significant improvements in PGA and PtGA in weeks 16 through 24, and in HAQ-DI at Week 24. The SBI/Pbo/Pbo and SBI/SBI/Pbo groups did not meet the primary endpoint but demonstrated improvements in several secondary endpoints. All treatment groups exhibited depletion of peripheral CD19+ B cells throughout the study. Overall, 61.5% of patients receiving SBI-087 and 55.0% of patients receiving Pbo reported adverse events.

CONCLUSION

SBI-087 effectively depleted peripheral CD20 B cells and was well tolerated. Improvements were consistently observed in the SBI/SBI/SBI group for the majority of efficacy and quality-of-life outcomes.

Methotrexate affects HMGB1 expression in rheumatoid arthritis, and the downregulation of HMGB1 prevents rheumatoid arthritis progression

High-mobility group box 1 (HMGB1) is associated with the development of rheumatoid arthritis (RA). Recent studies have shown that methotrexate (MTX) may inhibit the expression of HMGB1. This study examined whether HMGB1 might be involved in the treatment of RA using MTX. Synovial tissues were collected from RA patients who were treated with MTX for at least 6 months (RA-MTX group, 7 cases) and from those without MTX treatment (RA-noMTX group, 7 cases). Additionally, patients with osteoarthritis (OA group, 7 cases) were used as controls. The expression and locations of HMGB1 in the tissues were detected using real-time PCR, western blot, and immunohistochemistry. Additionally, OA-fibroblast-like synoviocytes (FLSs) and RA-FLSs were isolated and cultured, and the expression of HMGB1 was reduced in these cells by transfection with HMGB1 siRNA. Cell proliferation, migration, and invasion abilities were detected. Furthermore, the effects of HMGB1 on matrix metalloproteinase (MMP)-2 and MMP-13 were measured using western blot analysis. At the tissue level, HMGB1 expression in synovial membrane did not differ significantly between the OA and RA-MTX groups, but was significantly lower in these groups than in the RA-noMTX group. In cell experiments, the cell doubling time in the RA-FLS HMGB1 siRNA group was significantly extended compared with that in the RA-FLS negative control (NC)-siRNA group. The amount of cell migration and invasion in the RA-FLS HMGB1 siRNA group was significantly lower compared with that in the NC-siRNA group; the MMP-2 and MMP-13 expression levels were also lower. These results showed that MTX reduced HMGB1 expression in RA synovial tissues, and through the downregulation of HMGB1 expression in tissues, MTX may slow disease progression of RA.

Development of a bispecific antibody tetramerized through hetero-associating peptides

The specific assembly of self-associating peptides can be useful in building a functional antibody complex from small antibody fragments. We have focused on the exceedingly specific heterotetrameric assembly of Lin-2 and Lin-7 (L27) domains, which work as protein-protein interaction modules in many scaffold proteins. Here, we describe a novel method for constructing a highly functional antibody based on the hetero-association of L27 domains. In this study, we used a bacterial expression system to produce a bispecific antibody that was heterotetramerized through L27 domains and that targeted both epidermal growth factor receptor (EGFR) and Fcγ receptor III (FcγRIII or CD16). Gel electrophoresis, mass spectrometry and gel filtration analyses revealed that the constructed recombinant antibody was a disulfide-linked heterotetramer. The tetramerized antibody bound to EGFR and CD16 simultaneously, according to results from flow cytometry and surface plasmon resonance spectroscopy, respectively. Furthermore, we demonstrated that the bispecific antibody showed cytotoxic activity against EGFR-expressing tumor cells by using CD16-positive lymphocytes as effectors, and its cytotoxicity was comparable to that of a commercial therapeutic antibody. Taken together, the results show that our method has high potential for the cost-efficient production of highly active therapeutic antibodies.

The role of cytokines in the pathogenesis of rheumatoid arthritis--Practical and potential application of cytokines as biomarkers and targets of personalized therapy

Rheumatoid arthritis (RA), as a common chronic disease leading to severe disability, requires early diagnosis and introduction of proper treatment. Deregulation in the cytokine network plays an undoubtedly crucial role in the pathogenesis of RA. The understanding of the role of cytokines in RA can be used for patients' benefit. Technological advances had already allowed introduction of the tailor-made cytokine-targeted therapies (so far anti-TNF, anti-IL-1 and anti-IL-6) into clinical practice. This type of treatment is currently developing very fast. Moreover, cytokines are considered to be potential powerful biomarkers of RA with roles predicted to grow in the future. Detailed understanding of the cytokine balance in RA may assist both the diagnostic process and therapy.

Complementary action of granulocyte macrophage colony-stimulating factor and interleukin-17A induces interleukin-23, receptor activator of nuclear factor-κB ligand, and matrix metalloproteinases and drives bone and cartilage pathology in experimental arthritis: rationale for combination therapy in rheumatoid arthritis

Introduction

Type 17 T helper cells and interleukin (IL)-17 play important roles in the pathogenesis of human and murine arthritis. Although there is a clear link between IL-17 and granulocyte macrophage colony-stimulating factor (GM-CSF) in the inflammatory cascade, details about their interaction in arthritic synovial joints are unclear. In view of the introduction of GM-CSF and IL-17 inhibitors to the clinic, we studied how IL-17 and GM-CSF orchestrate the local production of inflammatory mediators during experimental arthritis.

Methods

To allow detection of additive, complementary or synergistic effects of IL-17 and GM-CSF, we used two opposing experimental approaches: treatment of arthritic mice with neutralising antibodies to IL-17 and GM-CSF and local overexpression of these cytokines in naive synovial joints. Mice were treated for 2 weeks with antibodies against IL-17 and/or GM-CSF after onset of collagen-induced arthritis. Naive mice were injected intraarticularly with adenoviral vectors for IL-17 and/or GM-CSF, resulting in local overexpression. Joint inflammation was monitored by macroscopic scoring, X-rays and histology. Joint washouts, synovial cell and lymph node cultures were analysed for cytokines, chemokines and inflammatory mediators by Luminex analysis, flow cytometry and quantitative polymerase chain reaction.

Results

Combined therapeutic anti-IL-17 and anti-GM-CSF ameliorated arthritis progression, and joint damage was dramatically reduced compared with treatment with anti-IL-17 or anti-GM-CSF alone. Anti-IL-17 specifically reduced synovial IL-23 transcription, whereas anti-GM-CSF reduced transcription of matrix metalloproteinases (MMPs) and receptor activator of nuclear factor κB ligand (RANKL). Overexpression of IL-17 or GM-CSF in naive knee joints elicited extensive inflammatory infiltrate, cartilage damage and bone destruction. Combined overexpression revealed additive and synergistic effects on the production of MMPs, RANKL and IL-23 in the synovium and led to complete destruction of the joint structure within 7 days.

Conclusions

IL-17 and GM-CSF differentially mediate the inflammatory process in arthritic joints and show complementary and local additive effects. Combined blockade in arthritic mice reduced joint damage not only by direct inhibition of IL-17 and GM-CSF but also by indirect inhibition of IL-23 and RANKL. Our results provide a rationale for combination therapy in autoinflammatory conditions, especially for patients who do not fully respond to inhibition of the separate cytokines.

Tumour necrosis factor α antagonists in the treatment of rheumatoid arthritis: an immunological perspective

Rheumatoid arthritis (RA) is one of the most prevalent autoimmune conditions, affecting approximately 1% of the adult population. It is associated with decreased quality of life and considerable morbidity and mortality. Various inflammatory cells, including macrophages, neutrophils, mast cells, natural killer cells, B and T cells and stromal cells play key pathophysiological roles in joint inflammation and RA progression. Several cytokines, including interleukin (IL)-1α and/or IL-1β, and tumour necrosis factor (TNF)-α, are involved at each stage of RA pathogenesis; namely, by augmenting autoimmunity, sustaining long-term inflammatory synovitis and promoting joint damage. Different cell types are involved in RA pathogenesis through upregulation of several cytokine and soluble pro-inflammatory mediators. As early as the late 1980s, TNF had been identified as a potential target in RA. Five anti-TNF drugs, infliximab, adalimumab, certolizumab pegol, etanercept and golimumab, are now approved for the treatment of RA in various countries. All are bivalent monoclonal antibodies, with the exception of the monovalent certolizumab and etanercept, which is an engineered dimeric receptor. Although all react with and neutralise soluble TNF in vitro, structural differences in the molecules may contribute to differences in their therapeutic effects and the occurrence of side effects. Pegylated certolizumab permits once-monthly dosing. Other mechanisms of action proposed to be important for the efficacy of anti-TNF agents are as follows: induction of apoptosis of both monocytes and T cells; neutralization of membrane TNF; antibody-dependent cell-mediated and complement-dependent cytotoxicity; and reverse signaling via membrane TNF.

Inhibition of the inflammatory cytokine tumor necrosis factor-alpha with etanercept provides protection against lethal H1N1 influenza infection in mice

INTRODUCTION

Factors implicated in influenza-mediated morbidity and mortality include robust cytokine production (cytokine storm), excessive inflammatory infiltrates, and virus-induced tissue destruction. Tumor necrosis factor-alpha (TNF-α) is an important pro-inflammatory cytokine present during influenza infection, but it is unclear whether direct inhibition of TNF-α can elicit protection against influenza infection.

METHODS

In this study, the commercially available TNF-α inhibitor etanercept was used to inhibit TNF-α induced by lethal A/FM/1/47 (H1N1) influenza virus infection of mice. The effects of TNF-α inhibition on mouse survival, pathologic changes, immune cell infiltration, inflammatory cytokine secretion, Toll-like receptor expression, and activation of the NF-κB (nuclear factor kappa B) signaling pathway were evaluated.

RESULTS

The intranasal delivery of etanercept provided significant protection against mortality (30% of mice survived up to 14 days after infection) in mice treated with etanercept. In contrast, no survivors were found beyond 6 days in mice treated with saline after lethal challenge with H1N1 influenza virus. It was observed that etanercept significantly reduced inflammatory cell infiltration (for example, macrophages and neutrophils), inflammatory cytokine secretion (for example, interleukin-6, TNF-α, and interferon gamma), and expression of Toll-like receptors (TLR-3, TLR-4, and TLR-7). Etanercept also downregulated and inhibited the cascade proteins of the NF-κB signaling pathway (for example, MyD88, TRIF, NF-κB, and p65), as well as enhanced host control of virus replication.

CONCLUSIONS

These findings indicate that etanercept, by blocking TNF-α, can significantly downregulate excessive inflammatory immune responses and provide protection against lethal influenza infection, making its use a novel strategy for controlling severe influenza-induced viral pneumonia.

GM-CSF as a therapeutic target in inflammatory diseases

GM-CSF is a well-known haemopoietic growth factor that is used in the clinic to correct neutropaenia, usually as a result of chemotherapy. GM-CSF also has many pro-inflammatory functions and recent data implicates GM-CSF as a key factor in Th17 driven autoimmune inflammatory conditions. In this review we summarize the findings that have led to the development of GM-CSF antagonists for the treatment of autoimmune diseases like rheumatoid arthritis (RA) and discuss some results of recent clinical trials of these agents.

Efficacy and safety of mavrilimumab in subjects with rheumatoid arthritis

Objectives

Mavrilimumab, a human monoclonal antibody targeting the alpha subunit of the granulocyte-macrophage colony-stimulating factor receptor, was evaluated in a phase 2 randomised, double-blind, placebo-controlled study to investigate efficacy and safety in subjects with rheumatoid arthritis (RA).

Methods

Subcutaneous mavrilimumab (10 mg, 30 mg, 50 mg, or 100 mg) or placebo was administered every other week for 12 weeks in subjects on stable background methotrexate therapy. The primary endpoint was the proportion of subjects achieving a ≥1.2 decrease from baseline in Disease Activity Score (DAS28-CRP) at week 12.

Results

55.7% of mavrilimumab-treated subjects met the primary endpoint versus 34.7% placebo (p=0.003) at week 12; for the 10 mg, 30 mg, 50 mg, and 100 mg groups, responses were 41.0% (p=0.543), 61.0% (p=0.011), 53.8% (p=0.071), and 66.7% (p=0.001) respectively. Response rate differences from placebo were observed at week 2 and increased throughout the treatment period. The 100 mg dose demonstrated a significant effect versus placebo on DAS28-CRP<2.6 (23.1% vs 6.7%, p=0.016), all categories of the American College of Rheumatology (ACR) criteria (ACR20: 69.2% vs 40.0%, p=0.005; ACR50: 30.8% vs 12.0%, p=0.021; ACR70: 17.9% vs 4.0%, p=0.030), and the Health Assessment Questionnaire Disability Index (−0.48 vs −0.25, p=0.005). A biomarker-based disease activity score showed a dose-dependent decrease at week 12, indicating suppression of disease-related biological pathways. Adverse events were generally mild or moderate in intensity. No significant hypersensitivity reactions, serious or opportunistic infections, or changes in pulmonary parameters were observed.

Conclusions

Mavrilimumab induced rapid clinically significant responses in RA subjects, suggesting that inhibiting the mononuclear phagocyte pathway may provide a novel therapeutic approach for RA.

Concordance of preclinical and clinical pharmacology and toxicology of monoclonal antibodies and fusion proteins: soluble targets

Monoclonal antibodies (mAbs) and fusion proteins directed towards soluble targets make an important contribution to the treatment of disease. The purpose of this review was to correlate the clinical and preclinical data on the 14 currently approved mAbs and fusion proteins targeted to soluble targets. The principal sources used to gather data were: the peer reviewed Literature; European Medicines Agency 'Scientific Discussions' and United States Food and Drug Administration 'Pharmacology/Toxicology Reviews' and package inserts (United States Prescribing Information). Data on the following approved biopharmaceuticals were included: adalimumab, anakinra, bevacizumab, canakinumab, certolizumab pegol, denosumab, eculizumab, etanercept, golimumab, infliximab, omalizumab, ranibizumab, rilonacept and ustekinumab. Some related biopharmaceuticals in late-stage development were also included for comparison. Good concordance with human pharmacodynamics was found for both non-human primates (NHPs) receiving the human biopharmaceutical and mice receiving rodent homologues (surrogates). In contrast, there was limited concordance for human adverse effects in genetically deficient mice, mice receiving surrogates or NHPs receiving the human pharmaceutical. In summary, the results of this survey show that although both mice and NHPs have good predictive value for human pharmacodynamics, neither species have good predictive value for human adverse effects. No evidence that NHPs have superior predictive value was found.