JAK inhibitors for the treatment of rheumatoid arthritis

Mechanistic insights into anti-inflammatory and immunosuppressive effects of plant secondary metabolites and their therapeutic potential for rheumatoid arthritis

The anti-inflammatory and immunosuppressive activities of plant secondary metabolites are due to their diverse mechanisms of action against multifarious molecular targets such as modulation of the complex immune system associated with rheumatoid arthritis (RA). This review discussed and critically analyzed the potent anti-inflammatory and immunosuppressive effects of several phytochemicals and their underlying mechanisms in association with RA in experimental studies, including preliminary clinical studies of some of them. A wide range of phytochemicals including phenols, flavonoids, chalcones, xanthones, terpenoids, alkaloids, and glycosides have shown significant immunosuppressive and anti-inflammatory activities in experimental RA models and a few have undergone clinical trials for their efficacy and safety in reducing RA symptoms and improve patient outcomes. These phytochemicals have potential as safer alternatives to the existing drugs in the management of RA, which possess a wide range of serious side effects. Sufficient preclinical studies on safety and efficacy of these phytochemicals must be performed prior to proper clinical studies. Further studies are needed to address the barriers that have so far limited their human use before the therapeutic potential of these plant-based chemicals as anti-arthritic agents in the treatment of RA is fully realized.

Influence of Janus kinase inhibitors on early postoperative complications in patients with rheumatoid arthritis undergoing orthopaedic surgeries

OBJECTIVE

We retrospectively reviewed the records of rheumatoid arthritis (RA) patients who underwent orthopaedic surgery to examine the influence of the perioperative use of Janus kinase (JAK) inhibitors on early postoperative complications.

PATIENTS AND METHODS

Thirty-two patients with RA under disease control with JAK inhibitors who underwent 49 orthopaedic procedures were included in the study. Patient records after surgery were investigated for surgical site infection (SSI), delayed wound healing (DWH), a flare-up of the disease, preoperative and postoperative absolute lymphocyte counts (ALCs), venous thromboembolism, and other postoperative complications.

RESULTS

JAK inhibitors were continued during the perioperative period in 31 procedures. In the remaining 18 procedures, JAK inhibitors were discontinued perioperatively with a mean discontinuation period of 2.4 days. No instances of SSI were identified in any patient during at least 90 days' follow-up, while DWH was seen in one patient. Disease flare-up was noted in two patients after 3 and 9 days of discontinuation of JAK inhibitors, respectively. The ALCs significantly decreased on postoperative Day 1 (P < .0001), and there was a significant correlation between pre- and post-one-day ALCs (r = 0.75, P < .0001).

CONCLUSION

JAK inhibitors seem to be safe during the perioperative period of orthopaedic surgery.

Improvement of Recalcitrant Dissecting Cellulitis of the Scalp After a Trial of Upadacitinib

Dissecting cellulitis of the scalp (DCS) is a rare condition characterized by painful inflammatory nodules and abscesses on the scalp, often leading to sinus tracts and scarring alopecia. We present a case of DCS in a 26-year-old male who experienced significant clinical improvement following a short course of upadacitinib, a Janus kinase (JAK) inhibitor. The patient received multiple standard treatments such as topical antimicrobials, oral antibiotics, corticosteroids, and intralesional triamcinolone injections, with limited success. However, following the initiation of upadacitinib, the patient reported reduced pain, pustular draining, and bleeding, with significantly improved quality of life. To our knowledge, there is currently a paucity of literature documenting the use of JAK inhibitors for DCS. This case aims to highlight the potential of JAK inhibitors as a therapy for refractory DCS, a condition with limited treatment options.

Identification of HHT-9041P1: A novel potent and selective JAK1 inhibitor in a rat model of rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic systemic disease associated with long-term disability and premature mortality. If left untreated, it can seriously affect patients' quality of life. The JAK-STAT signal transduction process is known to affect the occurrence and development of RA, and small molecule JAK inhibitors, such as tofacitinib, have been identified as treatments for RA. However, tofacitinib is a non-selective JAK inhibitor that was found to be associated with dose-limiting tolerability and safety issues, such as anemia in phase 2 dose-ranging studies. Therefore, we developed a selective JAK1 inhibitor, HHT-9041P1, to overcome target-related adverse reactions. We used enzyme and cytokine potency assays in vitro as well as the collagen-induced arthritis (CIA) model in vivo to explore the efficacy and mechanism. In vitro, HHT-9041P1 was diluted (0.017 nM-1 mM) in DMSO) and mixed with JAK1, JAK2, JAK3 or TYK2 kinases for use in the respective assays for inhibitory activity and selectivity evaluation. Fresh human PBMCs were activated and incubated with 100 ng/mL cytokine IL-6 or 20 ng/mL GM-CSF for use in the investigation of the immune mechanism. In vivo, HHT-9041P1 (1 mg/kg, 3 mg/kg and 10 mg/kg) was administered by oral gavage twice daily to CIA model Lewis rats from Day 8 to Day 29 for paw swelling and arthritis score evaluation. At the end of the experiment, the rats were sacrificed before collection of the hind ankle joint, spleen and blood for analysis of inflammation, arthritis phenotypes, inflammatory cytokine expression and Th1 cell proportions. As expected, HHT-9041P1 showed 10-fold greater selectivity for JAK1 over JAK2, and 23-fold greater selectivity over JAK3 in cellular assays. The high selectivity of HHT-9041P1 was also validated by in vivo safety studies. HHT-9041P1 demonstrated significant efficacy in a rat model of collagen-induced arthritis (CIA) and was associated with reduced helper T Cell 1 (Th1) cell differentiation. HHT-9041P1 also exhibited excellent pharmacokinetics properties. Thus, HHT-9041P1 was identified as a candidate for clinical development with many options for the treatment of RA.

Clinical Outcomes in Patients with Rheumatoid Arthritis After Switching Between Interleukin-6-Receptor Inhibitors and Janus Kinase Inhibitors: Findings from an Observational Study

INTRODUCTION

This observational study evaluated response in patients with rheumatoid arthritis (RA) who switched from an interleukin-6 receptor inhibitor (IL-6Ri) to a Janus kinase inhibitor (JAKi) and vice versa.

METHODS

Adult patients with RA, who initiated IL-6Ri or JAKi (following discontinuation of JAKi or IL-6Ri, respectively) during/after December 2012 and had a 6-month follow-up visit were enrolled. Clinical outcomes were evaluated at baseline and the follow-up visit. Continuous outcomes included Clinical Disease Activity Index (CDAI), Health Assessment Questionnaire (HAQ), pain, fatigue, tender joint count, swollen joint count, Physician Global Assessment (MDGA), Patient Global Assessment (PtGA), and morning stiffness duration. Categorical outcomes included the proportion of patients achieving CDAI low disease activity (LDA), remission, and minimal clinically important differences (MCIDs) for HAQ, pain, fatigue, MDGA, and PtGA. Continuous outcomes were summarized as mean changes from baseline, and categorical outcomes as response rates. Differences in the outcome measures between groups were evaluated using linear and logistic regression models.

RESULTS

Between IL-6Ri (n = 100) and JAKi initiators (n = 129), no significant differences were noted for continuous outcomes. Within both groups, a significant proportion of patients achieved LDA, remission, and MCIDs for other measures, although the odds of achieving LDA were higher among IL-6Ri (vs. JAKi) initiators with moderate-to-severe disease (adjusted odds ratio: 3.30 [1.01, 10.78]).

CONCLUSIONS

Patients with RA can achieve improvement in response when switching between IL-6Ri and JAKi. Although both therapies affect the IL-6 pathway, there are distinct mechanisms of action, which likely contribute to their clinical improvement, when reciprocally switched as follow-on treatments.

Cardiovascular manifestations of inflammatory bowel diseases and the underlying pathogenic mechanisms

Inflammatory bowel disease (IBD), consisting of ulcerative colitis and Crohn's disease, mainly affects the gastrointestinal tract but is also known to have extraintestinal manifestations because of long-standing systemic inflammation. Several national cohort studies have found that IBD is an independent risk factor for the development of cardiovascular disorders. However, the molecular mechanisms by which IBD impairs the cardiovascular system are not fully understood. Although the gut-heart axis is attracting more attention in recent years, our knowledge of the organ-to-organ communication between the gut and the heart remains limited. In patients with IBD, upregulated inflammatory factors, altered microRNAs and lipid profiles, as well as dysbiotic gut microbiota, may induce adverse cardiac remodeling. In addition, patients with IBD have a three- to four times higher risk of developing thrombosis than people without IBD, and it is believed that the increased risk of thrombosis is largely due to increased procoagulant factors, platelet count/activity, and fibrinogen concentration, in addition to decreased anticoagulant factors. The predisposing factors for atherosclerosis are present in IBD and the possible mechanisms may involve oxidative stress system, overexpression of matrix metalloproteinases, and changes in vascular smooth muscle phenotype. This review focuses mainly on 1) the prevalence of cardiovascular diseases associated with IBD, 2) the potential pathogenic mechanisms of cardiovascular diseases in patients with IBD, and 3) adverse effects of IBD drugs on the cardiovascular system. Also, we introduce here a new paradigm for the gut-heart axis that includes exosomal microRNA and the gut microbiota as a cause for cardiac remodeling and fibrosis.

Targeting cytokine storm as the potential anti-viral therapy: Implications in regulating SARS-CoV-2 pathogenicity

The latest global pandemic corona virus disease - 2019 (COVID-19) caused by the virus SARS-CoV-2 is still a matter of worrying concern both for the scientific communities and health care organizations. COVID-19 disease is proved to be a highly contagious disease transmitted through respiratory droplets and even close contact with affected individuals. COVID-19 disease is also understood to exhibit diverse symptoms of ranging severities i.e., from mild fatigue to death. Affected individuals' susceptibility to induce immunologic dysregulation phenomena termed 'cytokine storm' seems to be playing the damaging role of escalating the disease manifestation from mild to severe. Cytokine storm in patients with severe symptoms is understood to be characterized by enhanced serum levels of many cytokines including interleukin-1β, interleukin-6, IL-10, TNF, interferon-γ, MIP-1α, MIP-1β and VEGF. Since cytokine production in general is the most important antiviral defense response, understanding the COVID-19 associated cytokine storm in particular and differentiating it from the regular cytokine production response becomes crucial in developing an effective therapeutic strategy.This review focuses on the potential targeting of COVID-19 associated cytokine storm and its challenges.

The Association Between Rheumatoid Arthritis and Atrial Fibrillation: Epidemiology, Pathophysiology and Management

Atrial fibrillation (AF) is the most common cardiac arrhythmia with a significant increase in morbidity and mortality worldwide. Rheumatoid arthritis (RA), as a systemic inflammatory disease, affecting 0.5-1.0% of the adult population, is associated with increased incidence of cardiac arrhythmias such as AF. Several epidemiologic studies find that the risk of AF is increased in RA when compared with the general population. Other studies are inconsistent. Considering that inflammation plays an important role in AF, RA may be involved in the occurrence and development of AF. This review summarizes the epidemiology, pathophysiology, and management of AF in patients with RA.

Therapeutic drug monitoring of disease-modifying antirheumatic drugs in circulating leukocytes in immune-mediated inflammatory diseases

The treatment of immune-mediated inflammatory diseases (IMIDs) is one of the main challenges of modern medicine. Although a number of disease-modifying antirheumatic drugs (DMARDs) are available, there is wide variability in clinical response to treatment among individuals. Therapeutic drug monitoring (TDM) has been proposed to optimize treatment; however, some patients still experience unsatisfactory outcomes, although the blood concentrations of drugs in these patients remain in the therapeutic range. One possible reason for this is that the conventional samples (e.g., whole blood or plasma) used in TDM may not accurately reflect drug concentrations or concentrations of their metabolites at the target site. Hence, more refined TDM approaches to guide clinical decisions related to dose optimization are necessary. Circulating leukocytes or white blood cells have a critical role in driving the inflammatory process. They are recruited to the site of injury, infection and inflammation, and the main target of small molecule DMARDs is within immune cells. Given this, assaying drug concentrations in leukocytes has been proposed to be of possible relevance to the interpretation of outcomes. This review focuses on the clinical implications and challenges of drug monitoring of DMARDs in peripheral blood leukocytes from therapeutic or toxicological perspectives in IMIDs.

Effects of STAT Inhibitors in Mouse Models of Endometriosis

The signal transducer and activator of transcription (STAT) pathway, which regulates cell proliferation and immunity, has been implicated in chronic inflammatory diseases such as rheumatoid arthritis. However, few reports have described the effects of STAT inhibitors on endometriosis, another chronic inflammatory disease. Here, we investigated the intraperitoneal microenvironment and the effects of a STAT inhibitor in a mouse model of endometriosis. In the treatment group, a STAT3 inhibitor (Stattic®, 80 mg/kg) was orally administered three times per week; control animals received orally dosed phosphate-buffered saline. Endometriosis-like lesions and peritoneal lavage fluid were collected before and 1, 2, and 3 weeks after STAT3 inhibitor administration was initiated. The lesion area was significantly increased in both groups after the first week. However, in the treatment group, the lesion areas were significantly reduced at weeks 2 and 3 compared with week 1. Transforming growth factor (TGF)-β messenger RNA (mRNA) levels in ascites cells were significantly lower at weeks 1 and 2 than at week 0. Interleukin (IL)-6 mRNA levels were significantly higher at week 1 than at week 0 but were significantly lower at weeks 2 and 3 than at week 1. Thus, STAT inhibitors appeared to reduce the extent of endometriosis in this mouse model, and may also inhibit the IL-6 signaling pathway and reduce TGF-β levels. This study suggests that STAT inhibitors warrant further exploration for use in the treatment of endometriosis.

Upadacitinib for Patients with Rheumatoid Arthritis: A Comprehensive Review

Upadacitinib is a selective and reversible Janus kinase (JAK) inhibitor recently approved by the European Medicine Agency and the Food and Drug Administration for the treatment of rheumatoid arthritis (RA) at a dose of 15 mg/day. We present the chemical structure and mechanism of action of upadacitinib together with a comprehensive review of the efficacy of this drug in RA based on the SELECT clinical trial program and its safety profile. Its role in the management and therapeutic strategy of RA is also discussed. Upadacitinib in the different clinical trials has shown similar rates of clinical response, including the remission rates, regardless of the population analyzed (methotrexate-naïve, methotrexate-failure or biologic failure). In a head-to-head randomized clinical trial, upadacitinib plus methotrexate was superior to adalimumab when given on background methotrexate (MTX) in patients who have experienced an inadequate response to MTX. Upadacitinib also demonstrated superiority over abatacept in patients with RA after failure to previous biologic drugs. The safety profile of upadacitinib is generally consistent with those observed with biological or other JAK inhibitors.

Research on Liver Damage Caused by the Treatment of Rheumatoid Arthritis with Novel Biological Agents or Targeted Agents

Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by polyarticular, symmetric, and aggressive inflammation of the small joints in the hands and feet, resulting in dysfunction. With progress and development in medicine, treatment of RA is constantly evolving, making several drugs available for the treatment of RA. From the nonsteroidal anti-inflammatory drugs (NSAIDs) at the start of illness to glucocorticoids and then to conventional synthetic DMARDs (csDMARDs), biologic DMARDs (bDMARDs), and targeted synthetic DMARDs (tsDMARDs), therapeutic-use drugs for RA have been keeping pace with scientific research. However, various types of drugs have additional side effects when used over the long-term. New and emerging biological and targeted agents have been widely applied in recent years; however, the side effects have not been thoroughly investigated. In this paper, we review the research progress on liver damage caused by novel biological and targeted agents available for RA treatment. The aim is to provide a reference for rational clinical administration of such drugs.

Opportunistic infections associated with Janus kinase inhibitor treatment for rheumatoid arthritis: A structured literature review

BACKGROUND

The availability of Janus kinase (JAK) inhibitors has transformed the management of rheumatoid arthritis (RA), helping patients achieve clinical remission. However, the emergence of opportunistic infections (OIs) associated with the use of JAK inhibitors has been reported. This structured literature review was conducted to summarize reports of OIs associated with JAK inhibitor treatment for RA in clinical trials.

METHODS

Structured searches were performed in MEDLINE® and Embase® to identify relevant clinical trial data through March 2021. Bibliographic searches of recent reviews were also conducted, and gray literature searches were used to supplement key gap areas. Publications were screened, extracted, and quality assessed. Data were narratively synthesized.

RESULTS

Following screening, 105 publications describing 62 unique clinical trials reporting the rates of OIs in RA patients treated with JAK inhibitors were included. Overall, the highest exposure-adjusted incidence rate was reported for herpes zoster (HZ) infection (any form), followed by OI (any) and tuberculosis based on limited data from clinical trials with approved doses of JAK inhibitors. Lack of head-to-head trials and differences in trial design preclude direct comparison across JAK inhibitors. Higher rates of OIs were noted in the Asian and Australian populations compared with the global population. Higher rates of OIs were also noted with increasing dose of JAK inhibitors in most clinical trial data.

CONCLUSIONS

HZ was the most common OI reported among RA patients using all currently approved JAK inhibitors in clinical trials, although tuberculosis and other OIs were also reported. More long-term safety studies in the real-world setting are needed to compare the risk of OIs between various JAK inhibitors.

Characteristics of Patients Treated with JAK Inhibitors in Rheumatoid Arthritis before versus after VTE Risk Warnings

BACKGROUND

Baricitinib (BARI) or Tofacitinib (TOFA) were the first Janus Kinase Inhibitors (JAKi) to be marketed in rheumatoid arthritis (RA). Concerns regarding venous thromboembolism (VTE) risk have emerged during the past years. The aim of the study was to compare the baseline characteristics of patients initiating BARI or TOFA in RA before versus after European Medicine Agency (EMA)'s VTE warnings and to compare real-world persistence with these two drugs.

METHODS

In this multicentric cohort study, RA patients initiating BARI or TOFA were included from October 2017, date of BARI marketing authorization in France, to September 2020. Baseline characteristics regarding VTE risk were compared (before vs. after May 2019) by using pre-specified statistical tests. Comparison of persistence was assessed by using propensity-score methods.

RESULTS

232 patients were included; 155 with BARI and 77 with TOFA. Baseline characteristics of patients regarding VTE risk factors were not statistically different when Janus Kinase inhibitor (JAKi) was initiated before vs. after EMA's warnings although a trend towards a lower proportion of VTE history was observed. Five VTE events occurred, four with BARI, one with TOFA. Cumulative persistence rate at 2 years was similar between BARI and TOFA: HR 0.96; 95% Cl: 0.52 to 1.74; p = 0.89.

CONCLUSIONS

Our study did not show a significant change in patients characteristics starting a JAKi after the EMA's warnings, probably due to a lack of power. Though, the lower proportion of VTE history in patients after May 2019 suggests that rheumatologists have taken into account the potential VTE risk. These results need to be confirmed by further evidence.

Comparative efficacy and safety of JAK inhibitors and leflunomide in rheumatoid arthritis: A protocol for systematic review and meta-analysis

BACKGROUND

Rheumatoid arthritis is the most prevalent systemic autoimmune disease among the rheumatic inflammatory musculoskeletal diseases. Currently, there is no reliable evidence regarding the comparisons of anti-rheumatic effects between leflunomide and Janus kinase inhibitors. We performed a protocol for systematic review and meta-analysis to compare the efficacy and safety of Janus kinase inhibitors and leflunomide in rheumatoid arthritis.

METHODS

This review has been reported following the preferred reporting items for systematic reviews and meta-analyses protocol. We will search 7 electronic databases to identify relevant studies from inception to November, 2022, which includes PubMed, MEDLINE, Embase, Cochrane Clinical Trials Database, Web of Science, China National Knowledge Infrastructure, and Chinese Biomedical Literature Database. Risk of bias will be assessed according to the Cochrane Risk of Bias Tool. The Grading of Recommendations Assessment, Development and Evaluation system will be used to judge the overall quality of evidence supporting outcomes in this work. Data analysis was performed using Reviewer Manager 5.4.

RESULTS

The results of this systematic review will be published in a peer-reviewed journal.

CONCLUSION

This systematic review will provide evidence to judge whether Janus kinase inhibitors is superior to leflunomide in patients with in rheumatoid arthritis.

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.

SR-A neutralizing antibody: potential drug candidate for ameliorating osteoclastogenesis in rheumatoid arthritis

Rheumatoid arthritis (RA) is an autoimmune disease characterized by proliferative synovitis with deterioration of cartilage and bone. Osteoclasts (OCs) are the active participants in the bone destruction of RA. Although with great advances, most current therapeutic strategies for RA have limited effects on bone destruction. Macrophage scavenger receptor A (SR-A) is a class of pattern recognition receptors (PRRs) involved in bone metabolism and OC differentiation. More recently, our study revealed the critical role of SR-A in RA diagnosis and pathogenesis. Here, we further demonstrated that serum SR-A levels were positively correlated with bone destruction in patients with RA. Anti-SR-A neutralizing antibodies significantly inhibited OC differentiation and bone absorption in vitro in patients with RA, but not in healthy individuals, dampening the expression of OC-specific genes such as tartrate-resistant acid phosphatase (TRAP), cathepsin K (CTSK), and matrix metalloproteinase-9 (MMP-9). Similar results were also seen in collagen-induced arthritis (CIA) mice in vitro. Moreover, the anti-SR-A neutralizing antibody could further ameliorate osteoclastogenesis in vivo and ex vivo in CIA mice, accompanied by decreased serum levels of C-terminal telopeptide and IL-6, exhibiting potential protective effects. These results suggest that blockade of SR-A using anti-SR-A neutralizing antibodies might provide a promising therapeutic strategy for bone destruction in the RA.

Hyper-inflammatory responses in COVID-19 and anti-inflammatory therapeutic approaches

The coronavirus disease 2019 (COVID-19) is an ongoing global pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Patients with severe COVID-19 exhibit hyper-inflammatory responses characterized by excessive activation of myeloid cells, including monocytes, macrophages, and neutrophils, and a plethora of pro-inflammatory cytokines and chemokines. Accumulating evidence also indicates that hyper-inflammation is a driving factor for severe progression of the disease, which has prompted the development of anti-inflammatory therapies for the treatment of patients with COVID-19. Corticosteroids, IL-6R inhibitors, and JAK inhibitors have demonstrated promising results in treating patients with severe disease. In addition, diverse forms of exosomes that exert anti-inflammatory functions have been tested experimentally for the treatment of COVID-19. Here, we briefly describe the immunological mechanisms of the hyper-inflammatory responses in patients with severe COVID-19. We also summarize current anti-inflammatory therapies for the treatment of severe COVID-19 and novel exosome-based therapeutics that are in experimental stages.

Potential Adverse Events Reported With the Janus Kinase Inhibitors Approved for the Treatment of Rheumatoid Arthritis Using Spontaneous Reports and Online Patient Reviews

The aim of this study was to analyze the potential adverse events (AEs) caused by Janus kinase (JAK) inhibitors, including tofacitinib, baricitinib, and upadacitinib, used to treat rheumatoid arthritis using spontaneous AE reports from the FDA (FAERS) and interpreting them in correlation with those from Korea (KAERS) and an online patient review (WebMD). Potential AEs were identified based on a disproportionality analysis using the proportional reporting ratio (PRR), reporting odds ratio (ROR), and the information component (IC). A total of 23,720 reports were analyzed from FAERS database, of which 91.5% were reports on tofacitinib. Potentially important medical AEs related to infections were reported frequently, as well as thromboembolism-related AEs. The AEs, such as malignancy, interstitial lung diseases, myocardial infarction, and gastrointestinal disorder, also reported. In an online patient review report, the ineffectiveness of the drug and gastrointestinal AEs were frequently reported. Infection with baricitinib and symptoms related to pain or edema due to upadacitinib were the main discomfort experienced by patients. In conclusion, the results of this study highlight the possible safety issues associated with JAK inhibitors. Routine clinical observations and further research using various real-world databases are needed.

Molecular Modeling Insights into Upadacitinib Selectivity upon Binding to JAK Protein Family

Rheumatoid arthritis (RA) is a chronic disease characterized by bone joint damage and incapacitation. The mechanism underlying RA pathogenesis is autoimmunity in the connective tissue. Cytokines play an important role in the human immune system for signal transduction and in the development of inflammatory responses. Janus kinases (JAK) participate in the JAK/STAT pathway, which mediates cytokine effects, in particular interleukin 6 and IFNγ. The discovery of small molecule inhibitors of the JAK protein family has led to a revolution in RA therapy. The novel JAK inhibitor upadacitinib (Rinvoq^TM) has a higher selectivity for JAK1 compared to JAK2 and JAK3 in vivo. Currently, details on the molecular recognition of JAK1 by upadacitinib are not available. We found that characteristics of hydrogen bond formation with the glycine loop and hinge in JAKs define the selectivity. Our molecular modeling study could provide insight into the drug action mechanism and pharmacophore model differences in JAK isoforms.

Recent Advances in Understanding the Pathogenesis of Rheumatoid Arthritis: New Treatment Strategies

Rheumatoid arthritis (RA) is considered a chronic systemic, multi-factorial, inflammatory, and progressive autoimmune disease affecting many people worldwide. While patients show very individual courses of disease, with RA focusing on the musculoskeletal system, joints are often severely affected, leading to local inflammation, cartilage destruction, and bone erosion. To prevent joint damage and physical disability as one of many symptoms of RA, early diagnosis is critical. Auto-antibodies play a pivotal clinical role in patients with systemic RA. As biomarkers, they could help to make a more efficient diagnosis, prognosis, and treatment decision. Besides auto-antibodies, several other factors are involved in the progression of RA, such as epigenetic alterations, post-translational modifications, glycosylation, autophagy, and T-cells. Understanding the interplay between these factors would contribute to a deeper insight into the causes, mechanisms, progression, and treatment of the disease. In this review, the latest RA research findings are discussed to better understand the pathogenesis, and finally, treatment strategies for RA therapy are presented, including both conventional approaches and new methods that have been developed in recent years or are currently under investigation.

Clinical pharmacology of filgotinib in the treatment of rheumatoid arthritis: current insights

INTRODUCTION

Rheumatoid arthritis (RA) is a chronic autoimmune disease, whose natural course has been deeply modified thanks to the development of new therapeutic approaches. The Janus kinase inhibitors (Jakinibs) represent the newest class of drugs introduced for treating RA. Among these, Filgotinib (FIL) has been developed as Janus kinase1 (JAK1) selective inhibitor, specifically targeting key pro-inflammatory mediators in RA pathogenesis.

AREAS COVERED

This narrative review provides an overview on FIL as new therapeutic approach for RA, with focus on its pharmacological properties, clinical efficacy, and safety profile. The following electronic databases were adopted for the study search: PubMed, Google Scholar, ClinicalTrials.gov and Abstract archive from the American College of Rheumatology and the European Alliance of Associations for Rheumatology.

EXPERT OPINION

The phase II and phase III randomized controlled trials (RCTs) performed so far and their long-term extensions showed a comparable clinical efficacy of FIL to biologic treatments, with an acceptable safety profile. Thanks to these data, FIL was approved in Europe and Japan for the treatment of active RA, increasing the spectrum of therapeutic approaches and improving the possibility of a more tailored therapeutic strategy. Real-life data and head-to-head clinical trials will be needed to confirm its efficacy and safety.

JAK Inhibitors and Modulation of B Cell Immune Responses in Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a chronic, systemic immune-mediated inflammatory disease that can lead to joint destruction, functional disability and substantial comorbidity due to the involvement of multiple organs and systems. B cells have several important roles in RA pathogenesis, namely through autoantibody production, antigen presentation, T cell activation, cytokine release and ectopic lymphoid neogenesis. The success of B cell depletion therapy with rituximab, a monoclonal antibody directed against CD20 expressed by B cells, has further supported B cell intervention in RA development. Despite the efficacy of synthetic and biologic disease modifying anti-rheumatic drugs (DMARDs) in the treatment of RA, few patients reach sustained remission and refractory disease is a concern that needs critical evaluation and close monitoring. Janus kinase (JAK) inhibitors or JAKi are a new class of oral medications recently approved for the treatment of RA. JAK inhibitors suppress the activity of one or more of the JAK family of tyrosine kinases, thus interfering with the JAK-Signal Transducer and Activator of Transcription (STAT) signaling pathway. To date, there are five JAK inhibitors (tofacitinib, baricitinib, upadacitinib, peficitinib and filgotinib) approved in the USA, Europe and/ or Japan for RA treatment. Evidence from the literature indicates that JAK inhibitors interfere with B cell functions. In this review, the main results obtained in clinical trials, pharmacokinetic, in vitro and in vivo studies concerning the effects of JAK inhibitors on B cell immune responses in RA are summarized.

Efficacy and safety of filgotinib in Japanese patients with refractory rheumatoid arthritis: Subgroup analyses of a global phase 3 study (FINCH 2)

OBJECTIVES

To evaluate efficacy and safety of filgotinib in Japanese RA patients who have failed or were intolerant to one or more biologic disease-modifying antirheumatic drugs (bDMARD) from the global FINCH 2 study (NCT02873936).

METHODS

This subgroup analysis was performed using the predefined statistical analyses. The FINCH 2 study is a randomized, double-blind, placebo-controlled, Phase 3 study in adult RA patients with inadequate response to bDMARDs. The randomized patients were treated with once-daily filgotinib 200 mg, filgotinib 100 mg or placebo on a background of csDMARDs for 24 weeks.

RESULTS

Of 449 patients enrolled in the overall population, 40 patients were enrolled from Japan. In the Japanese population, the American College of Rheumatology 20% response rates at week 12 (primary endpoint) were 83.3% and 53.3% for filgotinib, 200 mg and 100 mg, respectively, vs 30.8% for placebo. Filgotinib was well tolerated, similar to the overall population.

CONCLUSIONS

Both doses of once-daily filgotinib 200 mg and filgotinib 100 mg were effective, and generally well-tolerated in Japanese patients with active refractory RA.

Current and novel therapeutic targets in the treatment of rheumatoid arthritis

Rheumatoid arthritis (RA), a multifactorial disease characterized by synovitis, cartilage destruction, bone erosion, and periarticular decalcification, finally results in impairment of joint function. Both genetic and environmental factors are risk factors in the development of RA. Unwanted side effects accompany most of the current treatment strategies, and around 20-40% of patients with RA do not clinically benefit from these treatments. The unmet need for new treatment options for RA has prompted research in the development of novel agents acting through physiologically and pharmacologically relevant targets. Here we discuss in detail three critical pathways, Janus kinase/signal transducer and activator of transcription (JAK/STAT), Th17, and hypoxia-inducible factor (HIF), and their roles as unique therapeutic targets in the field of RA. Some of the less developed but potential targets like nucleotide-binding and oligomerization domain-like receptor containing protein 3 (NLRP3) inflammasome and histone deacetylase 1 (HDAC1) are also discussed.