Anti-GM-CSF otilimab versus sarilumab or placebo in patients with rheumatoid arthritis and inadequate response to targeted therapies: a phase III randomised trial (contRAst 3)

Tissue macrophages: origin, heterogenity, biological functions, diseases and therapeutic targets

Macrophages are immune cells belonging to the mononuclear phagocyte system. They play crucial roles in immune defense, surveillance, and homeostasis. This review systematically discusses the types of hematopoietic progenitors that give rise to macrophages, including primitive hematopoietic progenitors, erythro-myeloid progenitors, and hematopoietic stem cells. These progenitors have distinct genetic backgrounds and developmental processes. Accordingly, macrophages exhibit complex and diverse functions in the body, including phagocytosis and clearance of cellular debris, antigen presentation, and immune response, regulation of inflammation and cytokine production, tissue remodeling and repair, and multi-level regulatory signaling pathways/crosstalk involved in homeostasis and physiology. Besides, tumor-associated macrophages are a key component of the TME, exhibiting both anti-tumor and pro-tumor properties. Furthermore, the functional status of macrophages is closely linked to the development of various diseases, including cancer, autoimmune disorders, cardiovascular disease, neurodegenerative diseases, metabolic conditions, and trauma. Targeting macrophages has emerged as a promising therapeutic strategy in these contexts. Clinical trials of macrophage-based targeted drugs, macrophage-based immunotherapies, and nanoparticle-based therapy were comprehensively summarized. Potential challenges and future directions in targeting macrophages have also been discussed. Overall, our review highlights the significance of this versatile immune cell in human health and disease, which is expected to inform future research and clinical practice.

Long-term safety and efficacy of anti-GM-CSF otilimab in patients with rheumatoid arthritis: long-term extension of three phase 3 randomised trials (contRAst X)

OBJECTIVES

To investigate the long-term safety and efficacy of otilimab, an antigranulocyte-macrophage colony-stimulating factor monoclonal antibody, for patients with rheumatoid arthritis (RA).

METHODS

ContRAst X (NCT04333147) was a phase 3, multicentre, long-term extension trial. Patients with RA aged ≥18 years who completed a qualifying contRAst trial (contRAst 1-3) and who the investigator thought might benefit from long-term otilimab treatment were eligible to enter contRAst X. Patients who received otilimab (90 mg/150 mg) in their qualifying trial maintained the same dose; patients who received tofacitinib or sarilumab were rerandomised 1:1 to either otilimab dose. Patients could continue background conventional synthetic disease-modifying antirheumatic drugs. The primary objective was long-term safety (up to 4 years).

RESULTS

Of the 2916 patients who entered contRAst X, 2915 received otilimab (exposure range: 7-896 days); the majority were withdrawn due to early trial termination. For otilimab 90 mg and 150 mg, the incidence of adverse events (AEs) was 62% (n=902/1456) and 64% (n=931/1459), the incidence of AEs of special interest was 8% (n=120/1456) and 7% (n=95/1459) and the incidence of serious AEs was 8% (n=123/1456) and 8% (n=114/1459), respectively. There were no instances of pulmonary alveolar proteinosis (PAP), active tuberculosis (TB), TB reactivation or serious hypersensitivity reactions. The proportions of clinical disease activity index low disease activity responders remained relatively stable throughout, with no apparent reduction following the switch from tofacitinib/sarilumab to otilimab.

CONCLUSION

No new safety signals or instances of PAP were associated with long-term (≤2.5 years) treatment with otilimab.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov: NCT04333147.

Therapeutic blockade of CCL17 in obesity-exacerbated osteoarthritic pain and disease

OBJECTIVES

We previously reported that CCL17 gene-deficient mice are protected from developing pain-like behaviour and exhibit less disease in destabilization of medial meniscus (DMM)-induced OA, as well as in high-fat diet (HFD)-exacerbated DMM-induced OA. Here, we explored if therapeutic neutralization of CCL17, using increasing doses of a neutralizing monoclonal antibody (mAb), would lead to a dose-dependent benefit in these two models.

DESIGN

DMM-induced OA was initiated in male mice either fed with a control diet (7% fat) or 8 weeks of a 60% HFD, followed by therapeutic intraperitoneal administration (i.e. when pain is evident) of an anti-CCL17 mAb (B293, 25mg/kg, 5mg/kg or 1mg/kg) or isotype control (BM4; 25mg/kg). Pain-like behaviour and arthritis were assessed by relative static weight distribution and histology, respectively. The effects of B293 (25mg/kg) on HFD-induced metabolic changes, namely oral glucose tolerance test, insulin tolerance test and liver triglyceride levels, were examined.

RESULTS

Therapeutic administration of B293 results in a dramatic amelioration of DMM-induced OA pain-like behaviour and the inhibition of disease progression, compared to BM4 (isotype control) treatment. A similar therapeutic effect was observed in HFD-exacerbated OA pain-like behaviour and disease. B293 treatment did not alter the measured HFD-induced metabolic changes.

CONCLUSIONS

Based on the data presented, CCL17 could be a therapeutic target in OA patients with joint injury alone or with obesity.

Expansion of granulocyte-macrophage colony-stimulating factor producing CD4+ T cells in an animal model with enhanced interleukin-1 signal

Interleukin-1, a pro-inflammatory cytokine, plays a crucial role in inflammatory disease pathogenesis. Interleukin-1 receptor antagonist knockout (IL-1Ra KO) mice spontaneously develop aortitis, arthritis and dermatitis, and are employed as a model for human inflammatory diseases. Previous studies have shown that transferring total T cells from IL-1Ra KO mice into nude mice induces aortitis and arthritis; however, the roles of specific T cell subsets in these inflammatory responses remain unclear. In this study, we aimed to investigate the T cell subsets in IL-1Ra KO mice. We found that the proportion of PD-1+CD44+CD62L-CD4+ T cells in the spleen and lymph nodes of IL-1Ra KO mice was significantly higher than that of wild type mice. RNA sequencing revealed elevated expression of basic helix-loop-helix family member e40 and granulocyte macrophage colony stimulating factor (GM-CSF) in splenic CD44+CD62L-CD4+ T cells from IL-1Ra KO mice. In addition, GM-CSF production from splenic CD4+ T cells of IL-1Ra KO mice was significantly higher than that of wild type mice when stimulated with PMA and ionomycin in vitro. Notably, immunohistochemical staining showed infiltration of GM-CSF+CD4+ T cells at inflammatory sites in IL-1Ra KO mice. Our results suggest that a subset of GM-CSF+CD4 + T cells emerges under IL-1 signal-enhanced inflammatory conditions.

An interdisciplinary perspective on peripheral drivers of pain in rheumatoid arthritis

Pain is one of the most debilitating symptoms of rheumatoid arthritis (RA), and yet remains poorly understood, especially when pain occurs in the absence of synovitis. Without active inflammation, experts most often attribute joint pain to central nervous system dysfunction. However, advances in the past 5 years in both immunology and neuroscience research suggest that chronic pain in RA is also driven by a variety of abnormal interactions between peripheral neurons and mediators produced by resident cells in the local joint environment. In this Review, we discuss these novel insights from an interdisciplinary neuro-immune perspective. We outline a potential working model for the peripheral drivers of pain in RA, which includes autoantibodies, resident immune and mesenchymal cells and their interactions with different subtypes of peripheral sensory neurons. We also offer suggestions for how future collaborative research could be designed to accelerate analgesic drug development.

Serum GM-CSF level is a predictor of treatment response to tocilizumab in rheumatoid arthritis patients: a prospective observational cohort study

BACKGROUND

The aim of this prospective observational cohort study was to unveil the predictors of treatment response to tocilizumab (TCZ) therapy in rheumatoid arthritis (RA) patients, in terms of clinical characteristics and serum proinflammatory cytokines, especially to explore the predictive value of granulocyte macrophage-colony stimulating factor (GM-CSF).

METHODS

Active adult RA patients with inadequate response to MTX intending to receive TCZ therapy were recruited prospectively in the study. A total of 174 severe RA patients were included for the identification of the associations between treatment response and the following characteristic features: demographics, medications, disease activity, serum proinflammatory cytokines and so on.

RESULTS

Disease duration (OR = 0.996), tender joint count (TJC)/68 (OR = 0.943), neutrophil ratio (W4/baseline) (OR = 0.224), the high level of GM-CSF > 5 ng/ml (OR = 0.414) at baseline were the independent adverse predictors of good response assessed by clinical disease activity index (CDAI) at week 24 (W24) for TCZ therapy in RA patients. Moreover, DAS28-ESR (OR = 2.951, P = 0.002) and the high level of GM-CSF > 10 ng/ml at baseline (OR = 5.419, P = 0.002) were independent predictors of poor response, but not the high level of GM-CSF > 5 ng/ml (OR = 2.713, P = 0.054). The patients in the high GM-CSF group had significantly higher DAS28-ESR and serum levels of cytokines (IL-17A, IL-1β, IL-6, TNF-α) at baseline, as well as significantly higher rate of non-good response (62.8% vs. 39.4%, P = 0.010) and poor response (27.9% vs. 9.1%, P = 0.004) than the low GM-CSF group at W24. In addition, poor responders had significantly higher levels of GM-CSF with concomitant increase in the serum levels of IL-17A and IL-1β at baseline than those in moderate and good response groups, while serum levels of IL-6 and TNF-α at baseline were not significantly different in three response groups.

CONCLUSION

The high levels of GM-CSF (> 5 ng/ml and > 10 ng/ml) at baseline were the independent predictors of non-good response and poor response to TCZ at W24 respectively. The high level of GM-CSF at baseline is a marker of high disease activity and a predictor of poor response to TCZ in severe RA patients, which may facilitate the development of individualized treatment strategies for refractory RA.

Non-TNF biologics and their biosimilars in rheumatoid arthritis

INTRODUCTION

Rheumatoid arthritis (RA) is a chronic inflammatory rheumatic disease that affects both the articular and extra-articular structures, leading to significant joint damage, disability and excess mortality. The treatment algorithm of RA has changed tremendously in the past 1-2 decades because of the emergence of novel biological therapies that target different mechanisms of action in addition to TNFα.

AREAS COVERED

This article summarizes the evidence and safety of the non-TNF biological DMARDs in the treatment of RA, including those that target B cells, T-cell co-stimulation, interleukin (IL)-6 and granulocyte-monocyte colony-stimulating factor (GM-CSF). The targeted synthetic DMARDs such as the Janus kinase inhibitors are not included. The availability of the less costly biosimilars has enabled more patients to receive biological therapy earlier in the course of the disease. The evidence for the non-TNF biosimilar compounds in RA is also reviewed.

EXPERT OPINION

There are unmet needs of developing novel therapeutic agents to enhance the response rate and provide more options for difficult-to-treat RA. These include the newer generation biologic and targeted synthetic DMARDs. A personalized treatment strategy in RA requires evaluation of the cellular, cytokine, genomic and transcriptomic profile that would predict treatment response to biologic or targeted DMARDs of different mechanisms of action.

What rheumatologists need to know about mRNA vaccines: current status and future of mRNA vaccines in autoimmune inflammatory rheumatic diseases

Messenger RNA (mRNA) vaccines as a novel vaccine platform offer new tools to effectively combat both emerging and existing pathogens which were previously not possible. The 'plug and play' feature of mRNA vaccines enables swift design and production of vaccines targeting complex antigens and rapid incorporation of new vaccine constituents as needed. This feature makes them likely to be adopted for widespread clinical use in the future.Currently approved mRNA vaccines include only those against SARS-CoV-2 virus. These vaccines demonstrate robust immunogenicity and offer substantial protection against severe disease. Numerous mRNA vaccines against viral pathogens are in the early to late phase of development. Several mRNA vaccines for influenza are tested in clinical trials, with some already in phase 3 studies. Other vaccines in the early and late phases of development include those targeting Cytomegalovirus, varicella zoster virus, respiratory syncytial virus and Epstein-Barr virus. Many of these vaccines will likely be indicated for immunosuppressed populations including those with autoimmune inflammatory rheumatic diseases (AIIRD). This review focuses on the mechanism, safety and efficacy of mRNA in general and summarises the status of mRNA vaccines in development for common infectious diseases of particular interest for patients with AIIRD.

New molecular targets in the treatment of rheumatoid arthritis

PURPOSE OF REVIEW

This review will discuss selected emerging molecular targets and associated potential therapeutic agents for rheumatoid arthritis (RA)-directed treatment.

RECENT FINDINGS

Agents in active development for RA treatment include those targeted to CD40 and CD40 ligand, programmed death protein 1 (PD-1), and granulocyte-macrophage colony-stimulating factor (GM-CSF). Several other molecules with a strong theoretical role in RA pathogenesis and/or demonstrated efficacy in other autoimmune diseases are also being evaluated as potential drug targets in preclinical or translational studies in RA. These targets include interleukin 1 receptor associated kinases 1 and 4 (IRAK1, IRAK4), tyrosine kinase 2 (Tyk2), bradykinin receptor 1 (B1R), OX40 and OX40 ligand.

SUMMARY

Identification of molecular targets for RA treatment remains an active area of investigation, with multiple therapeutic agents in clinical and preclinical development.