Biomarkers for Treatment Response in Rheumatoid Arthritis: Where are they?

The Minor Phytocannabinoid Delta-8-Tetrahydrocannabinol Attenuates Collagen-Induced Arthritic Inflammation and Pain-Depressed Behaviors

Patients with arthritis report using cannabis for pain management, and the major cannabinoid delta-9-tetrahydrocannabinol (Δ9-THC) has anti-inflammatory properties, yet the effects of minor cannabinoids on arthritis are largely unknown. The goal of the present study was to determine the antiarthritic potential of the minor cannabinoid delta-8-tetrahydrocannabinol (Δ8-THC) using the collagen-induced arthritis (CIA) mouse model. Adult male DBA/1J mice were immunized and boosted 21 days later with an emulsion of collagen and complete Freund's adjuvant. Beginning on the day of the booster, mice were administered twice-daily injections of Δ8-THC (3 or 30 mg/kg), the steroid dexamethasone (2 mg/kg), or vehicle for two weeks. Dorsal-ventral paw thickness and qualitative measures of arthritis were recorded daily, and latency to fall from an inverted grid was measured on alternating days, to determine arthritis severity and functional impairment. On the final day of testing, spontaneous wire-climbing behavior and temperature preference in a thermal gradient ring were measured to assess CIA-depressed behavior. The Δ8-THC treatment (30 mg/kg) reduced paw swelling and qualitative signs of arthritis. Δ8-THC also blocked CIA-depressed climbing and CIA-induced preference for a heated floor without producing locomotor effects but did not affect latency to fall from a wire grid. In alignment with the morphologic and behavioral assessments in vivo, histology revealed that Δ8-THC reduced synovial inflammation, proteoglycan loss and cartilage and bone erosion in the foot joints in a dose-dependent manner. Together, these findings suggest that Δ8-THC not only blocked morphologic changes but also prevented functional loss caused by collagen-induced arthritis. SIGNIFICANCE STATEMENT: Despite increasing use of cannabis products, the potential effects of minor cannabinoids are largely unknown. Here, the minor cannabinoid delta-8-tetrahydrocannabinol blocked the development of experimentally induced arthritis by preventing both pathophysiological as well as functional effects of the disease model. These data support the development of novel cannabinoid treatments for inflammatory arthritis.

A Network-Based Framework to Discover Treatment-Response-Predicting Biomarkers for Complex Diseases

The potential of precision medicine to transform complex autoimmune disease treatment is often challenged by limited data availability and inadequate sample size when compared with the number of molecular features found in high-throughput multi-omics data sets. To address this issue, the novel framework PRoBeNet (Predictive Response Biomarkers using Network medicine) was developed. PRoBeNet operates under the hypothesis that the therapeutic effect of a drug propagates through a protein-protein interaction network to reverse disease states. PRoBeNet prioritizes biomarkers by considering i) therapy-targeted proteins, ii) disease-specific molecular signatures, and iii) an underlying network of interactions among cellular components (the human interactome). PRoBeNet helped discover biomarkers predicting patient responses to both an established autoimmune therapy (infliximab) and an investigational compound (a mitogen-activated protein kinase 3/1 inhibitor). The predictive power of PRoBeNet biomarkers was validated with retrospective gene-expression data from patients with ulcerative colitis and rheumatoid arthritis and prospective data from tissues from patients with ulcerative colitis and Crohn disease. Machine-learning models using PRoBeNet biomarkers significantly outperformed models using either all genes or randomly selected genes, especially when data were limited. These results illustrate the value of PRoBeNet in reducing features and for constructing robust machine-learning models when data are limited. PRoBeNet may be used to develop companion and complementary diagnostic assays, which may help stratify suitable patient subgroups in clinical trials and improve patient outcomes.

Patients with High Baseline Neutrophil-to-Lymphocyte Ratio Exhibit Better Response to Filgotinib as Treatment for Rheumatoid Arthritis

INTRODUCTION

High baseline neutrophil-to-lymphocyte ratio (NLR) in rheumatoid arthritis (RA) has been associated with positive responses to biologic tumor necrosis factor inhibition and negative responses to conventional synthetic disease-modifying antirheumatic drug (csDMARD) triple therapy. Datasets from three randomized clinical trials in patients with RA were used to test the hypothesis that baseline NLR is associated with improved clinical response to filgotinib in methotrexate (MTX)-naïve or MTX-experienced RA populations.

METHODS

Patients from FINCH 1 (inadequate response to MTX, MTX-IR; NCT02889796), FINCH 2 (inadequate response to biologic DMARDs; NCT02873936), and FINCH 3 (MTX-naïve; NCT02886728) were classified as baseline NLR-High or baseline NLR-Low based on a previously published cut point of 2.7. In total, 3365 patients were included across the three studies. Differences in clinical outcomes and patient-reported outcomes (PROs) were determined using linear-regression models.

RESULTS

Control-arm patients (placebo + MTX/placebo + csDMARD) classified as NLR-High exhibited worse continuous clinical and PRO responses at week 12 across clinical trials compared to NLR-Low patients. In contrast, NLR-High patients who received FIL 200 mg + MTX/csDMARD exhibited consistently better responses after 12 weeks compared to NLR-Low patients across clinical trials, clinical endpoints, and PROs. These trends were most prominent among the MTX-IR population.

CONCLUSION

The 2.7 baseline NLR cut point could be used to enrich for patients most likely to benefit from the addition of filgotinib to background MTX/csDMARD. Use of baseline NLR as part of therapeutic decision-making would not require additional diagnostics and could contribute to improved outcomes for patients with RA.

TRIAL REGISTRATION

Clinicaltrials.gov: NCT02889796; NCT02873936; NCT02886728.

The dichotomy of glucocorticosteroid treatment in immune-inflammatory rheumatic diseases: an evidence-based perspective and insights from clinical practice

Objectives

Glucocorticosteroids (GCs) are the most used anti-inflammatory and immunosuppressive drugs due to their effectiveness in managing pain and disease modification in many immune-inflammatory rheumatic diseases (IRDs). However, their use is limited because of adverse effects (AEs).

Material and methods

The authors analyzed recent studies, including randomized controlled trials (RCTs), observational, translational studies and systematic reviews, providing an in-depth viewpoint on the benefits and drawbacks of GC use in rheumatology.

Results

Glucocorticosteroids are essential in managing life-threatening autoimmune diseases and a cornerstone in many IRDs given their swift onset of action, necessary in flares. Several RCTs and meta-analyses have demonstrated that when administered over a long time and on a low-dose basis, GC can slow the radiographic progression in early rheumatoid arthritis (RA) patients by at least 50%, satisfying the conventional definition of a disease-modifying anti-rheumatic drug (DMARD). In the context of RA treatment, the use of modified-release prednisone formulations at night may offer the option of respecting circadian rhythms of both inflammatory response and HPA activation, thereby enabling low-dose GC administration to mitigate nocturnal inflammation and prolonged morning fatigue and joint stiffness. Long-term GC use should be individualized based on patient characteristics and minimized due to their potential AEs. Their chronic use, especially at medium/high dosages, might cause irreversible organ damage due to the burden of metabolic systemic effects and increased risk of infections. Many international guidelines recommend tapering/withdrawal of GCs in sustained remission. Treat-to-target (T2T) strategies are critical in setting targets for disease activity and reducing/discontinuing GCs once control is achieved.

Conclusions

Glucocorticosteroids' use in treating IRDs should be judicious, focused on minimizing use, tapering and discontinuing treatment, when possible, to improve long-term safety. Glucocorticosteroids remain part of many therapeutic regimens, particularly at low doses, and elderly RA patients, especially with associated chronic comorbidities, may benefit from long-term low-dose GC treatment. A personalized GC therapy is essential for optimal long-term outcomes.

Perspectives on applying immuno-autonomics to rheumatoid arthritis: results from an online rheumatologist survey

The term "immuno-autonomics" has been coined to describe an emerging field evaluating the interaction between stress, autonomic nervous system (ANS), and inflammation. The field remains largely unknown among practicing rheumatologists. Our objective was to evaluate the perspectives of rheumatologists regarding the role of stress in the activity and management of rheumatoid arthritis (RA). A 31-item survey was conducted with 231 rheumatologists. Rheumatologists were asked to assess the role of stress in rheumatoid arthritis (RA) disease activity and were provided with information regarding immuno-autonomics. They were asked to consider how immuno-autonomics resonated with their patient management needs. The majority of rheumatologists are eager to better understand non-response, believe that stress biology and ANS dysfunction interfere with disease activity, and embrace the theory that measurement of ANS via next-generation HRV may be able to evaluate autonomic dysfunction and the biology of stress. Rheumatologists are open to the idea that quantitative measurement of ANS function using next-generation HRV can be a helpful tool to RA practice. The majority agree that ANS state influences RA disease control and that quantitative measures of ANS state are helpful to RA practice. Rheumatologists also agree that patients with poor ANS function may be at risk for not responding adequately to conventional, biologic, or targeted synthetic DMARDs. Almost all would use an in-office test to quantitatively measure ANS using next-generation HRV. This study shows that rheumatologists are open to embracing evaluation of ANS function as a possible tool in the management and treatment of RA.