Precision medicine in rheumatoid arthritis

Evaluation of proximod, a selective agonist of sphingosine-1-phosphate receptor-1, in healthy volunteers and patients with rheumatoid arthritis: a phase 1, double-blind, randomised, placebo-controlled, ascending dose trial

BACKGROUND

Proximod is a selective agonist of sphingosine-1-phosphate receptor-1 (S1PR1). It acts by redirecting lymphocytes from the circulation to secondary lymph nodes, and is under development as an immunomodulator for rheumatoid arthritis. We aimed to evaluate the safety, pharmacokinetics, and preliminary efficacy of proximod in healthy volunteers and patients with rheumatoid arthritis.

METHODS

We did a two part, phase 1, double-blind, randomised, placebo-controlled, ascending dose trial at a single centre in China. Eligible participants were adults aged 18-50 years with a BMI of 18-28 kg/m2 for healthy volunteers and aged 18-70 years with a BMI of 18-30 kg/m2 for patients with rheumatoid arthritis. In part 1, healthy volunteers were randomly assigned within ten cohorts to receive a single oral dose of proximod (0·125 mg, 0·25 mg, 0·5 mg, 1 mg, 1·5 mg, 2 mg, 3 mg, 5 mg, 10 mg, or 15 mg in cohorts 1-10) or placebo. In part 2, healthy volunteers were randomly assigned to receive once-daily doses of proximod 5 mg or placebo, and patients with rheumatoid arthritis were randomly assigned to receive once-daily doses of proximod 5 mg, proximod 10 mg, or placebo, for 28 days. Patients and investigators were masked to treatment assignment. The primary outcomes were safety, tolerability, and pharmacokinetic profile of proximod for 72 days in healthy volunteers and for 48 days in patients with rhematoid arthritis, assessed in all treated participants. This trial is registered with ClinicalTrials.gov (NCT06361199, NCT06361186), and is complete.

FINDINGS

Between Nov 1, 2017, and June 22, 2021, 124 healthy volunteers were randomly assigned in part 1 of the study and 124 were included in the analyses (mean age 34·3 years [SD 6·9], 62 [50%] of 124 participants were women and 62 [50%] were men, and 116 [94%] were Han Chinese ethnicity). Between Feb 16, 2022, and Oct 8, 2023, 113 participants were screened for inclusion in part 2 (80 healthy volunteers and 33 patients with rheumatoid arthritis). 79 participants were excluded and 34 were randomly assigned (10 healthy participants and 24 patients with rheumatoid arthritis), 34 of whom were included in the analyses. Ten (100%) of ten healthy participants were Han Chinese ethnicity, with a mean age of 39·9 years (SD 7·3). Five (50%) of ten healthy volunteers were women and five (50%) were men). 22 (92%) of 24 participants with rheumatoid arthritis were Han Chinese ethnicity, with a mean age of 52·7 years (SD 6·8). 22 (92%) of 24 patients with rheumatoid arthritis were women and two (8%) were men. In part 1, all doses of proximod were well tolerated, with no dose-related adverse reactions or serious adverse events observed. In part 2, 74 adverse reactions were reported in eight (80%) of ten healthy volunteers and 22 (92%) of 24 patients with rheumatoid arthritis. Adverse events associated with proximod were predominantly mild or moderate. In part 2, the concentration of proximod and its active metabolite, proximod-phosphate, gradually increased in all three groups receiving proximod and the EC50 of the S1PR1 agonist for proximod-phosphate (6·1 ng/mL) was reached on day 14 for both 5 mg groups, and on day 7 for the 10 mg group. The mean Ctrough values for proximod-phosphate on day 28 were 7·7 ng/mL and 10·2 ng/mL for 5 mg in healthy volunteers and patients with rheumatoid arthritis, respectively, and 15·3 ng/mL for 10 mg in patients with rheumatoid arthritis. In patients with rheumatoid arthritis, lymphocyte count decreased after treatment in all proximod groups reaching nadir at approximately day 28, with a corresponding percentage decline from baseline of 65·25% in the 5 mg group, 71·64% in the 10 mg group, and 20·57% in the placebo group.

INTERPRETATION

Proximod exhibited good tolerability over the 28-day treatment period, demonstrating its potential in reducing blood lymphocyte count. These results highlight the promise of the S1PR1 agonist proximod as a potential candidate for rheumatoid arthritis treatment, warranting further investigation in subsequent clinical studies.

FUNDING

Beijing Union Pharmaceutical Factory and Jian Kuan (Suzhou) Biotechnology.

Biologics or Janus Kinase Inhibitors in Rheumatoid Arthritis Patients Who are Insufficient Responders to Conventional Anti-Rheumatic Drugs

Rheumatoid arthritis (RA) is a chronic immune-mediated inflammatory disease which can induce progressive disability if not properly treated early. Over the last 20 years, the improvement of knowledge on the pathogenesis of the disease has made available several drugs targeting key elements of the pathogenetic process, which now represent the preferred treatment option after the failure of first-line therapy with conventional drugs such as methotrexate (MTX). To this category of targeted drugs belong anti-cytokine or cell-targeted biological agents and more recently also Janus kinase inhibitors (JAKis). In the absence to date of specific biomarkers to guide the therapeutic choice in the context of true precision medicine, the choice of the first targeted drug after MTX failure is guided by treatment cost (especially after the marketing of biosimilar products) and by the clinical characteristics of the patient (age, sex, comorbidities and compliance) and the disease (presence or absence of autoantibodies and systemic or extra-articular manifestations), which may influence the efficacy and safety profile of the available products. This viewpoint focuses on the decision-making process underlying the personalized approach to RA therapy and will analyse the evidence in the literature supporting the choice of individual products and in particular the differential choice between biological drugs and JAKis.

The impacts of obesity in rheumatoid arthritis and insights into therapeutic purinergic modulation

Rheumatoid Arthritis (RA) is an autoimmune condition responsible for the impairment of synovia and joints, endangering the functionality of individuals and contributing to mortality. Currently, obesity is increasing worldwide, and recent studies have suggested an association between such condition and RA. In this sense, obese individuals present a lower capacity for achieving remission and present more intense symptoms of the disease, demonstrating a link between both disorders. Different studies aim to understand the possible connection between the conditions; however, few is known in this sense. Therefore, knowing that obesity can alter the activity of multiple body systems, this work's objective is to evaluate the main modifications caused by obesity, which can be linked to the pathophysiology of RA, highlighting as relevant topics obesity's negative impact triggering systemic inflammation, intestinal dysbiosis, endocrine disbalances. Furthermore, the relationship between oxidative stress and obesity also deserves to be highlighted, considering the influence of reactive oxygen species (ROS) accumulation in RA exacerbation. Additionally, many of those characteristics influenced by obesity, along with the classic peculiarities of RA pathophysiology, can also be associated with purinergic signaling. Hence, this work suggests possible connections between the purinergic system and RA, proposing potential therapeutic targets against RA to be studied.

Different gender of oxidative balance score on the risk of rheumatoid arthritis in the US population from NHANES

BACKGROUND

Oxidative stress is associated with risk of pathogenesis between rheumatoid arthritis. The Oxidative Balance Score (OBS) is a systematic tool to assess the effects of diet and lifestyle in relation to oxidative stress. However, the association between OBS and rheumatoid arthritis has not been reported previously. We conducted a cross-sectional study to investigate the complex association between OBS and rheumatoid arthritis in US adults.

METHODS

Overall, 9747 participants were included in this cross-sectional study. The exposure variable was OBS, which was scored by 16 dietary and four lifestyle factors. Multivariate logistic regression, subgroup analysis, and restricted cubic spline (RCS) regression were used to analyze the association between OBS and rheumatoid arthritis.

RESULTS

Compared to the lowest OBS quartile group (Q1), the multivariate corrected odds ratio (OR) (95% confidence interval [CI]) for the highest quartile of OBS (Q4) was 0.69 (0.52-0.90) (p = .013 for trend); furthermore, the RCS showed a negative linear relationship between OBS and rheumatoid arthritis. According to subgroup and RCS analyses, there was a significant difference between the association of OBS and with rheumatoid arthritis in terms of gender (p = .049).

CONCLUSION

In conclusion, high OBS was negatively associated with the risk of rheumatoid arthritis. Gender has an effect on OBS in RA. Our results suggest that OBS can be used as a biomarker to predict rheumatoid arthritis.

Clinical Phenotypes, Serological Biomarkers, and Synovial Features Defining Seropositive and Seronegative Rheumatoid Arthritis: A Literature Review

Rheumatoid arthritis (RA) is a chronic autoimmune disorder which can lead to long-term joint damage and significantly reduced quality of life if not promptly diagnosed and adequately treated. Despite significant advances in treatment, about 40% of patients with RA do not respond to individual pharmacological agents and up to 20% do not respond to any of the available medications. To address this large unmet clinical need, several recent studies have focussed on an in-depth histological and molecular characterisation of the synovial tissue to drive the application of precision medicine to RA. Currently, RA patients are clinically divided into "seropositive" or "seronegative" RA, depending on the presence of routinely checked antibodies. Recent work has suggested that over the last two decades, long-term outcomes have improved significantly in seropositive RA but not in seronegative RA. Here, we present up-to-date differences in epidemiology, clinical features, and serological biomarkers in seronegative versus seropositive RA and discuss how histological and molecular synovial signatures, revealed by recent large synovial biopsy-based clinical trials, may be exploited to refine the classification of RA patients, especially in the seronegative group.

Thermally-responsive and reduced glutathione-sensitive folate-targeted nanocarrier based on alginate and pluronic F127 for on-demand release of methotrexate

A specific rheumatoid arthritis (RA)-microenvironment-triggered nanocarrier for RA treatment of a first-line antirheumatic drug (Methotrexate, MTX) has been proposed. Reduced glutathione (GSH) responsivity, cystamine, was first introduced on the alginate backbone, which was then used as the bridge to connect pluronic F127 (temperature-responsive factor) and folic acid (targeting factor for active immune cells), resulting in dual-responsive triggered targeting carrier, PCAC-FA. In vitro study demonstrated that PCAC-FA was preferentially taken up by activated macrophage cells rather than normal ones, suggesting the targeting of PCAC-FA to inflamed tissue. The loading capacity of the designed carrier was 21.23 ± 0.91 %. MTX from the PCAC-FA carrier was significantly accelerated release in the presentation of glutathione or in cold shock condition, proposing the efficacy-controlled release. MTX@PCAC-FA showed excellent hemocompatibility, confirming a suitable application with parenteral administration. Notably, the acute and subacute toxicity in the mice model showed that the toxicity of MTX had significantly reduced after encapsulating in the PCAC-FA carrier. These nanoplatforms not only provide an alternative safe strategy for the clinical treatment of rheumatoid arthritis with MTX but also deliver MTX selectively and provide on-demand drug release via external and internal signals, thus emerging as a promising therapeutic option for precise RA therapy.

Synovial Tissue Insights into Heterogeneity of Rheumatoid Arthritis

PURPOSE OF REVIEW

Rheumatoid arthritis is one of the most common rheumatic and autoimmune diseases. While it can affect many different organ systems, RA primarily involves inflammation in the synovium, the tissue that lines joints. Patients with RA exhibit significant clinical heterogeneity in terms of presence or absence of autoantibodies, degree of permanent deformities, and most importantly, treatment response. These clinical characteristics point to heterogeneity in the cellular and molecular pathogenesis of RA, an area that several recent studies have begun to address.

RECENT FINDINGS

Single-cell RNA-sequencing initiatives and deeper focused studies have revealed several RA-associated cell populations in synovial tissues, including peripheral helper T cells, autoimmunity-associated B cells (ABCs), and NOTCH3+ sublining fibroblasts. Recent large transcriptional studies and translational clinical trials present frameworks to capture cellular and molecular heterogeneity in RA synovium. Technological developments, such as spatial transcriptomics and machine learning, promise to further elucidate the different types of RA synovitis and the biological mechanisms that characterize them, key elements of precision medicine to optimize patient care and outcomes in RA. This review recaps the findings of those recent studies and puts our current knowledge and future challenges into scientific and clinical perspective.

Multi-omics analysis identifies IgG2b class-switching with ALCAM-CD6 co-stimulation in joint-draining lymph nodes during advanced inflammatory-erosive arthritis

Introduction

Defective lymphatic drainage and translocation of B-cells in inflamed (Bin) joint-draining lymph node sinuses are pathogenic phenomena in patients with severe rheumatoid arthritis (RA). However, the molecular mechanisms underlying this lymphatic dysfunction remain poorly understood. Herein, we utilized multi-omic spatial and single-cell transcriptomics to evaluate altered cellular composition (including lymphatic endothelial cells, macrophages, B-cells, and T-cells) in the joint-draining lymph node sinuses and their associated phenotypic changes and cell-cell interactions during RA development using the tumor necrosis factor transgenic (TNF-Tg) mouse model.

Methods

Popliteal lymph nodes (PLNs) from wild-type (n=10) and TNF-Tg male mice with "Early" (5 to 6-months of age; n=6) and "Advanced" (>8-months of age; n=12) arthritis were harvested and processed for spatial transcriptomics. Single-cell RNA sequencing (scRNAseq) was performed in PLNs from the TNF-Tg cohorts (n=6 PLNs pooled/cohort). PLN histopathology and ELISPOT along with ankle histology and micro-CT were evaluated. Histopathology of human lymph nodes and synovia was performed for clinical correlation.

Results

Advanced PLN sinuses exhibited an increased Ighg2b/Ighm expression ratio (Early 0.5 ± 0.1 vs Advanced 1.4 ± 0.5 counts/counts; p<0.001) that significantly correlated with reduced talus bone volumes in the afferent ankle (R2 = 0.54, p<0.001). Integration of single-cell and spatial transcriptomics revealed the increased IgG2b+ plasma cells localized in MARCO+ peri-follicular medullary sinuses. A concomitant decreased Fth1 expression (Early 2.5 ± 0.74 vs Advanced 1.0 ± 0.50 counts, p<0.001) within Advanced PLN sinuses was associated with accumulation of iron-laden Prussian blue positive macrophages in lymph nodes and synovium of Advanced TNF-Tg mice, and further validated in RA clinical samples. T-cells were increased 8-fold in Advanced PLNs, and bioinformatic pathway assessment identified the interaction between ALCAM+ macrophages and CD6+ T-cells as a plausible co-stimulatory mechanism to promote IgG2b class-switching.

Discussion

Collectively, these data support a model of flare in chronic TNF-induced arthritis in which loss of lymphatic flow through affected joint-draining lymph nodes facilitates the interaction between effluxing macrophages and T-cells via ALCAM-CD6 co-stimulation, initiating IgG2b class-switching and plasma cell differentiation of the expanded Bin population. Future work is warranted to investigate immunoglobulin clonality and potential autoimmune consequences, as well as the efficacy of anti-CD6 therapy to prevent these pathogenic events.

Cartilage organoids for cartilage development and cartilage-associated disease modeling

Cartilage organoids have emerged as powerful modelling technology for recapitulation of joint embryonic events, and cartilage regeneration, as well as pathophysiology of cartilage-associated diseases. Recent breakthroughs have uncovered "mini-joint" models comprising of multicellular components and extracellular matrices of joint cartilage for development of novel disease-modifying strategies for personalized therapeutics of cartilage-associated diseases. Here, we hypothesized that LGR5-expressing embryonic joint chondroprogenitor cells are ideal stem cells for the generation of cartilage organoids as "mini-joints" ex vivo "in a dish" for embryonic joint development, cartilage repair, and cartilage-associated disease modelling as essential research models of drug screening for further personalized regenerative therapy. The pilot research data suggested that LGR5-GFP-expressing embryonic joint progenitor cells are promising for generation of cartilage organoids through gel embedding method, which may exert various preclinical and clinical applications for realization of personalized regenerative therapy in the future.

3D Cell Culture as Tools to Characterize Rheumatoid Arthritis Signaling and Development of New Treatments

Rheumatoid arthritis (RA) is one of the most common autoimmune disorders affecting 0.5-1% of the population worldwide. As a disease of multifactorial etiology, its constant study has made it possible to unravel the pathophysiological processes that cause the illness. However, efficient and validated disease models are necessary to continue the search for new disease-modulating drugs. Technologies, such as 3D cell culture and organ-on-a-chip, have contributed to accelerating the prospecting of new therapeutic molecules and even helping to elucidate hitherto unknown aspects of the pathogenesis of multiple diseases. These technologies, where medicine and biotechnology converge, can be applied to understand RA. This review discusses the critical elements of RA pathophysiology and current treatment strategies. Next, we discuss 3D cell culture and apply these methodologies for rheumatological diseases and selected models for RA. Finally, we summarize the application of 3D cell culture for RA treatment.