Efficacy and safety of peficitinib (ASP015K) in patients with rheumatoid arthritis and an inadequate response to methotrexate: results of a phase III randomised, double-blind, placebo-controlled trial (RAJ4) in Japan

The efficacy and safety of different Janus kinase inhibitors as monotherapy in rheumatoid arthritis: A Bayesian network meta-analysis

OBJECTIVE

This study aims to evaluate the efficacy and safety of JAK inhibitors in the treatment of patients with RA.

METHODS

The databases CNKI, VIP, Wanfang, CBM, and PubMed, Embase, Cochrane Library and Web of Science were searched to identify relevant randomized controlled trials (RCTs), all from the time of database creation to April 2024. Screening, data extraction, and risk of bias assessment (using Review Manager-5.3 software) were independently performed by at least two authors. The network meta-analysis was conducted using R 4.1.3 software. PROSPERO registration number: CRD42022370444.

RESULTS

Thirty-three RCTs included 15,961 patients The experimental groups involved six JAK inhibitors (filgotinib, tofacitinib, decernotinib, baricitinib, upadacitinib and peficitinib) and 12 interventions (different doses of the six JAK inhibitors), and the control group involved adalimumab (ADA) and placebo. Compared with placebo, all JAK inhibitors showed a significant increase in efficacy measures (ACR20/50/70). Compared with ADA, only tofacitinib, low-dose decernotinib, and high-dose peficitinib showed a significant increase in ACR20/50/70. Decernotinib ranked first in the SUCRA ranking of ACR20/50/70. In terms of safety indicators, only those differences between low-dose filgotinib and high-dose upadacitinib, low-dose tofacitinib and high-dose upadacitinib were statistically significant. Low-dose filgotinib ranked first in the SUCRA ranking with adverse events as safety indicators. Only the efficacy and safety of tofacitinib ranked higher among different SUCRA rankings.

CONCLUSION

Six JAK inhibitors have better efficacy than placebo. The superior efficacy of decernotinib and safety of low-dose filgotinib can be found in the SUCRA. However, there are no significant differences in safety between the different JAK inhibitors. Head-to-head trials, directly comparing one against each other, are required to provide more certain evidence.

Exploring the therapeutic potential of regulatory T cell in rheumatoid arthritis: Insights into subsets, markers, and signaling pathways

Rheumatoid arthritis (RA) is a complex autoimmune inflammatory rheumatic disease characterized by an imbalance between immunological reactivity and immune tolerance. Regulatory T cells (Tregs), which play a crucial role in controlling ongoing autoimmunity and maintaining peripheral tolerance, have shown great potential for the treatment of autoimmune inflammatory rheumatic diseases such as RA. This review aims to provide an updated summary of the latest insights into Treg-targeting techniques in RA. We focus on current therapeutic strategies for targeting Tregs based on discussing their subsets, surface markers, suppressive function, and signaling pathways in RA.

Comparative efficacy of five approved Janus kinase inhibitors as monotherapy and combination therapy in patients with moderate-to-severe active rheumatoid arthritis: a systematic review and network meta-analysis of randomized controlled trials

Background

The European League of Rheumatology(EULAR)guidelines recommend Janus kinase (JAK) inhibitors for patients with moderate to severe rheumatoid arthritis (RA) who are insensitive or under-responsive to conventional synthetic disease-modifying anti-rheumatic drugs (csDMARDs). But there was no recommendation for which one was preferred in five currently approved JAK inhibitors. The objective of this network meta-analysis study was to evaluate the efficacy of five JAK inhibitors as monotherapy and combination therapy in patients with moderate-to-severe active rheumatoid arthritis.

Methods

The randomized controlled trials (RCTs) of tofacitinib, baricitinib, upadacitinib, filgotinib and peficitinib as monotherapy or combined with csDMARD in the treatment of active RA were searched in database of PubMed, Embase, Web of Science and Cochrane Library, up to December 2023. The control group included placebo or csDMARD. Outcome indicators included American College of Rheumatology 20% response (ACR20), ACR50, ACR70 and the percentage of patients achieving 28-joint disease activity score using C-reactive protein (DAS28(CRP))<2.6 at 12 weeks and 24 weeks. The statistical analysis was performed by Stata14 and RevMan5.4. Data processing, network evidence plots, surface under the cumulative ranking curve (SUCRA) ranking, league plots and funnel plots were generated. Risk ratio (RR) and 95% confidence interval (95%CI) as effect sizes to analyze the statistics.

Results

This study included thirty-six RCTs with 16,713 patients. All JAK inhibitors were more effective than placebo in ACR20 (RRs ranging between 1.74 and 3.08), ACR50 (RRs ranging between 2.02 and 7.47), ACR70 (RRs ranging between 2.68 and 18.13), DAS28(CRP) < 2.6 (RRs ranging between 2.70 and 7.09) at 12 weeks. Upadacitinib 30 mg and upadacitinib 15 mg showed relatively good efficacy according to their relative SUCRA ranking. All JAK inhibitors were more effective than csDMARD or placebo in ACR20 (RRs ranging between 1.16 and 1.86), ACR50 (RRs ranging between 1.69 and 2.84), ACR70 (RRs ranging between 1.50 and 4.47), DAS28(CRP) < 2.6 (RRs ranging between 2.28 and 7.56) at 24 weeks. Upadacitinib 15 mg + csDMARD and baricitinib 4 mg + csDMARD showed relatively good efficacy according to their relative SUCRA ranking. The safety analysis results such as serious infection, malignancy, major adverse cardiovascular event (MACE), and venous thromboembolic events (VTE) showed no statistical difference.

Conclusion

This NMA study indicated that all JAK inhibitors performed better than placebo. Based on the results of this study, upadacitinib 30 mg, upadacitinib 15 mg, upadacitinib 15 mg + csDMARD and baricitinib 4 mg + csDMARD were recommended treatment options with relatively good efficacy and safety. However, attention should be paid to monitoring the occurrence of adverse events in high-risk RA patients with medication. Combination therapy with csDMARD might be more suitable for the maintenance of long-term efficacy. However, in clinical practice, it is still necessary to select the appropriate therapeutic regimen based on the actual clinical situation.

Post hoc analysis of patients with rheumatoid arthritis under clinical remission in two Japanese Phase 3 trials of peficitinib treatment (RAJ3 and RAJ4)

OBJECTIVE

We evaluated remission rates and their relationship with baseline characteristics in patients with rheumatoid arthritis treated with the oral Janus kinase inhibitor peficitinib.

METHODS

This post hoc analysis of data from two Phase 3 studies (RAJ3 and RAJ4) of peficitinib (100 and 150 mg/day) in Asian rheumatoid arthritis patients investigated clinical disease activity index (CDAI) remission and low disease activity rates from baseline to Week 52. CDAI, Health Assessment Questionnaire-Disability Index, and van der Heijde-modified total Sharp score remission/low disease activity rates at Week 52 were evaluated among patients achieving CDAI remission at Weeks 12/28. Logistic regression analyses explored the relationship between baseline characteristics and CDAI remission/low disease activity rates.

RESULTS

CDAI remission rates increased over time in a dose-dependent manner in both peficitinib-treated groups. Most patients achieving CDAI remission at Weeks 12/28 also achieved remission at Week 52. Following the multivariate analysis of demographic and baseline characteristics, factors associated with the achievement of CDAI remission at Week 28 included male sex, low baseline prednisone dose (RAJ3 only), and low baseline Disease Activity Score 28-C-reactive protein (RAJ4 only).

CONCLUSIONS

Peficitinib demonstrated persistent efficacy in clinical remission to Week 52. Baseline characteristics associated with CDAI remission were mostly consistent with previous studies using other disease-modifying antirheumatic drugs.

Novel and potential future therapeutic options in systemic autoimmune diseases

Autoimmune inflammation is caused by the loss of tolerance to specific self-antigens and can result in organ-specific or systemic disorders. Systemic autoimmune diseases affect a significant portion of the population with an increasing rate of incidence, which means that is essential to have effective therapies to control these chronic disorders. Unfortunately, several patients with systemic autoimmune diseases do not respond at all or just partially respond to available conventional synthetic disease-modifying antirheumatic drugs and targeted therapies. However, during the past few years, some new medications have been approved and can be used in real-life clinical settings. Meanwhile, several new candidates appeared and can offer promising novel treatment options in the future. Here, we summarize the newly available medications and the most encouraging drug candidates in the treatment of systemic lupus erythematosus, rheumatoid arthritis, Sjögren's disease, systemic sclerosis, systemic vasculitis, and autoimmune myositis.

Immune pathogenesis of idiopathic granulomatous mastitis: from etiology toward therapeutic approaches

Idiopathic granulomatous mastitis (IGM) is a noncancerous, chronic inflammatory disorder of breast with unknown causes, posing significant challenges to the quality of life due to its high refractoriness and local aggressiveness. The typical symptoms of this disease involve skin redness, a firm and tender breast mass and mastalgia; others may include swelling, fistula, abscess (often without fever), nipple retraction, and peau d'orange appearance. IGM often mimics breast abscesses or malignancies, particularly inflammatory breast cancer, and is characterized by absent standardized treatment options, inconsistent patient response and unknown mechanism. Definite diagnosis of this disease relies on core needle biopsy and histopathological examination. The prevailing etiological theory suggests that IGM is an autoimmune disease, as some patients respond well to steroid treatment. Additionally, the presence of concurrent erythema nodosum or other autoimmune conditions supports the autoimmune nature of the disease. Based on current knowledge, this review aims to elucidate the autoimmune-favored features of IGM and explore its potential etiologies. Furthermore, we discuss the immune-mediated pathogenesis of IGM using existing research and propose immunotherapeutic strategies for managing this condition.

Selectivity, efficacy and safety of JAKinibs: new evidence for a still evolving story

Fundamental insight gained over the last decades led to the discovery of cytokines as pivotal drivers of inflammatory diseases such as rheumatoid arthritis, psoriasis/psoriasis arthritis, inflammatory bowel diseases, atopic dermatitis and spondylarthritis. A deeper understanding of the pro-inflammatory and anti-inflammatory effects of various cytokines has prompted new cytokine-targeting therapies, which revolutionised the treatment options in the last years for patients with inflammatory disorders. Disease-associated immune responses typically involve a complex interplay of multiple cytokines. Therefore, blockade of one single cytokine does not necessarily lead to a persistent remission in all patients with inflammatory disorders and fostered new therapeutic strategies targeting intracellular pathways shared by multiple cytokines. By inhibiting JAK-STAT signalling pathways common to families of cytokines, JAK-inhibitors (JAKinibs) have created a new paradigm for the treatment of inflammatory diseases. Multiple agents have been approved for various disorders and more are being investigated for several new indications. Second-generation selective JAKinibs have been devised with the aim to achieve an increased selectivity and a possible reduced risk of side effects. In the current review, we will summarise the current body of evidence of pan versus selective JAKinibs and the most recent insights on new side effects and indications, including COVID-19.

Significance of m6A in subtype identification, immunological evolution, and therapeutic sensitivity of RA

N6-methyladenosine (m6A) is one kind of important epigenetic modification pattern which is extensively involved in immune regulation. The development and progression of autoimmune diseases are closely related to immune dysregulation. Considering that rheumatoid arthritis (RA) is a typical autoimmune disease, the m6A process might be one of the important regulatory mechanisms in the pathogenesis of RA. In this study, we identified five differentially expressed m6A regulators in normal and RA samples from the GEO database. With these five regulators, we constructed the nomogram, and it could accurately identify the risk of RA morbidity. Next, we identified 121 differentially expressed genes (DEGs) between normal and RA samples, of which 36 DEGs were co-expressed with these five m6A regulators. We noted that these DEGs were highly enriched in multiple immunoregulatory signaling pathways, such as cytokine-mediated immune cell chemotaxis, adhesion, and activation. To further characterize the heterogeneity of immunological features, we clustered the RA samples into two subtypes. The C2 subtype has higher infiltration levels of pro-inflammatory cells and activity of pro-inflammatory signaling pathways. Thus, the inflammatory response might be more vigorous in the C2 subtype. Next, we constructed the m6Asig system with the SVM machine learning algorithms and least absolute shrinkage and selection operator (LASSO) regression. The m6Asig could accurately distinguish the C1 and C2 subtypes, which indicated that the m6Asig could be a potential biomarker for the inflammatory activity of RA. Finally, by comparing the information from the CellMiner, TTD, and DrugBank databases, we determined 25 drugs. The targets of these drugs were positively correlated with m6Asig. To be clarified, the above findings were derived from bioinformatics and statistical analyses, and further experimental validation still requires. In summary, this study further revealed the m6A and immunoregulation mechanisms in RA pathogenesis. Also, the m6Asig could be a novel biomarker with potential applicability in the clinical management of RA.

Multifunctional nanoparticle-mediated combining therapy for human diseases

Combining existing drug therapy is essential in developing new therapeutic agents in disease prevention and treatment. In preclinical investigations, combined effect of certain known drugs has been well established in treating extensive human diseases. Attributed to synergistic effects by targeting various disease pathways and advantages, such as reduced administration dose, decreased toxicity, and alleviated drug resistance, combinatorial treatment is now being pursued by delivering therapeutic agents to combat major clinical illnesses, such as cancer, atherosclerosis, pulmonary hypertension, myocarditis, rheumatoid arthritis, inflammatory bowel disease, metabolic disorders and neurodegenerative diseases. Combinatorial therapy involves combining or co-delivering two or more drugs for treating a specific disease. Nanoparticle (NP)-mediated drug delivery systems, i.e., liposomal NPs, polymeric NPs and nanocrystals, are of great interest in combinatorial therapy for a wide range of disorders due to targeted drug delivery, extended drug release, and higher drug stability to avoid rapid clearance at infected areas. This review summarizes various targets of diseases, preclinical or clinically approved drug combinations and the development of multifunctional NPs for combining therapy and emphasizes combinatorial therapeutic strategies based on drug delivery for treating severe clinical diseases. Ultimately, we discuss the challenging of developing NP-codelivery and translation and provide potential approaches to address the limitations. This review offers a comprehensive overview for recent cutting-edge and challenging in developing NP-mediated combination therapy for human diseases.

Safety and efficacy of peficitinib in Asian patients with rheumatoid arthritis who had an inadequate response or intolerance to methotrexate: results of a multicenter, randomized, double-blind, placebo-controlled phase 3 study

Background

The efficacy and safety of the oral Janus kinase inhibitor peficitinib were investigated in Asian patients with rheumatoid arthritis (RA).

Methods

In this double-blind, phase 3 study, patients from mainland China, Korea, and Taiwan with RA and an inadequate response/intolerance to methotrexate were randomized (1:1:1) to once-daily placebo (N = 128), peficitinib 100 mg (N = 129), or 150 mg (N = 128) in combination with non-biologic DMARDs. At Week 24, patients receiving placebo switched to peficitinib 100 mg or 150 mg. American College of Rheumatology (ACR) 20 response at Week 24/early termination (ET) was the primary endpoint. Adverse events (AEs) were assessed. The study was registered at ClinicalTrials (NCT03660059).

Findings

385 patients were included in the analysis. ACR20 responses were statistically significantly higher in both peficitinib 100 mg (56.6%) and 150 mg (56.3%) groups versus placebo (24.2%); Odds Ratio (95% confidence interval, CI) 4.14 (2.42, 7.08) and 4.07 (2.38, 6.96), respectively (both P < 0.001) at Week 24/ET. The incidence rate of herpes zoster related disease (herpes zoster and varicella) was higher in patients who received peficitinib versus placebo, but no dose dependency was observed (incidence rate/100 patient-years (95% CI): peficitinib 6.7 (4.32, 10.37); placebo 3.7 (0.93, 14.88).

Interpretation

In Asian patients with RA and an inadequate response/intolerance to methotrexate, peficitinib 100 mg and 150 mg demonstrated superiority to placebo in the reduction of RA symptoms and was well tolerated. No additional benefit was observed with use of the higher peficitinib dose in this study population of predominantly Chinese patients.

Funding

Astellas Pharma.

Japan College of Rheumatology guidance for the use of methotrexate in patients with rheumatoid arthritis: Secondary publication

Methotrexate (MTX), the anchor drug in the current treatment strategy for rheumatoid arthritis (RA), was first approved for the treatment of RA in Japan in 1999 at a recommended dose of 6-8 mg/week. The approved maximum dose of MTX has been 16 mg/week since February 2011 when MTX was approved as a first-line drug in the treatment of RA. Recent evidence of MTX-polyglutamate concentration in the red blood cells of Japanese patients with RA justifies the current daily use of MTX in Japan. Additionally, after a nationwide clinical trial, a subcutaneous MTX injection formula (7.5-15 mg/week) was approved for RA treatment in September 2022. Therefore, in March 2023, a subcommittee of the Japan College of Rheumatology updated the guidance (formerly 'guidelines') for the use of MTX in Japanese patients with RA. This article, an abridged English translation summarizing the 2023 update of the Japan College of Rheumatology guidance for the use of MTX and management of patients with RA, will be helpful to both Japanese and global rheumatology communities.

Safety and effectiveness of peficitinib 100 mg/day in patients achieving clinical remission from a long-term open-label extension study in Japan, Korea, and Taiwan (RAJ2)

OBJECTIVES

This post hoc analysis of the RAJ2 study assessed long-term safety and effectiveness of peficitinib 100 mg/day for treatment of rheumatoid arthritis.

METHODS

Eligible patients previously completed two Phase 3 (RAJ3 and RAJ4) studies of peficitinib in Asia. All patients received peficitinib 100 mg/day at RAJ2 Week (W)0; dose change to 50 mg/day or 150 mg/day was permitted. Safety endpoints included treatment-emergent adverse events and laboratory test results. Effectiveness endpoints included peficitinib exposure pattern, achievement of Clinical Disease Activity Index (CDAI) remission by peficitinib exposure pattern at W0 and W48, and association of demographics/characteristics with CDAI remission at W0 and W48.

RESULTS

Overall, no new safety findings were reported at W48, and renal function was unaffected. Of patients included in effectiveness analyses at W48, 70.9% (451/636) had maintained peficitinib 100 mg/day since W0. Of patients who achieved CDAI remission at W0 and maintained peficitinib 100 mg/day to W48, 50.3% (79/157) maintained CDAI remission to W48. Low disease activity and a lower number of prior disease-modifying antirheumatic drugs were significantly associated with CDAI remission at W48.

CONCLUSIONS

Long-term peficitinib treatment at a dose of 100 mg/day was generally well tolerated and, following induction therapy, maintained effectiveness through to W48.

Real-world comparative study of the efficacy of Janus kinase inhibitors in patients with rheumatoid arthritis: the ANSWER cohort study

OBJECTIVE

This multicentre, retrospective study compared the efficacy and safety of tofacitinib, baricitinib, peficitinib and upadacitinib in real-world clinical settings after minimizing selection bias and adjusting the confounding patient characteristics.

METHOD

The 622 patients were selected from the ANSWER cohort database and treated with tofacitinib (TOF), baricitinib (BAR), peficitinib (PEF) or upadacitinib (UPA). The patient's background was matched using propensity score-based inverse probability of treatment weighting (IPTW) among four treatment groups. The values of Clinical Disease Activity Index (CDAI), C-reactive protein (CRP), and modified Health Assessment Questionnaire (mHAQ) after drug initiation and the remission or low disease activity (LDA) rates of CDAI at 6 months after drug initiation were compared among the four groups. Further, the predictive factor for TOF and BAR efficacy was analysed.

RESULTS

The retention and discontinuation rates until 6 months after drug initiations were not significantly different among the four JAK inhibitors treatment groups. Mean CDAI value, CDAI remission rate, and CDAI-LDA rate at 6 months after drug initiation were not significantly different among treatment groups. Baseline CDAI (TOFA: OR 1.09, P < 0.001; BARI: OR 1.07, P < 0.001), baseline CRP (TOFA: OR 1.32, P = 0.049), baseline glucocorticoid dose (BARI: OR 1.18, 95% CI 1.01-1.38, P = 0.035), a number of previous biological or targeted synthetic disease-modifying antirheumatic drugs (biological/targeted synthetic DMARDs) (BARI: OR 1.36, P = 0.004) were predictive factors for resistance to CDAI-LDA achievement to JAK inhibitor treatment.

CONCLUSION

The efficacy and safety of TOF, BAR, PEF and UPA were not significantly different for the treatment of patients with rheumatoid arthritis.

Signaling pathways in macrophages: molecular mechanisms and therapeutic targets

Macrophages play diverse roles in development, homeostasis, and immunity. Accordingly, the dysfunction of macrophages is involved in the occurrence and progression of various diseases, such as coronavirus disease 2019 and atherosclerosis. The protective or pathogenic effect that macrophages exert in different conditions largely depends on their functional plasticity, which is regulated via signal transduction such as Janus kinase-signal transducer and activator of transcription, Wnt and Notch pathways, stimulated by environmental cues. Over the past few decades, the molecular mechanisms of signaling pathways in macrophages have been gradually elucidated, providing more alternative therapeutic targets for diseases treatment. Here, we provide an overview of the basic physiology of macrophages and expound the regulatory pathways within them. We also address the crucial role macrophages play in the pathogenesis of diseases, including autoimmune, neurodegenerative, metabolic, infectious diseases, and cancer, with a focus on advances in macrophage-targeted strategies exploring modulation of components and regulators of signaling pathways. Last, we discuss the challenges and possible solutions of macrophage-targeted therapy in clinical applications. We hope that this comprehensive review will provide directions for further research on therapeutic strategies targeting macrophage signaling pathways, which are promising to improve the efficacy of disease treatment.

JAK-STAT inhibitors in Immune mediated diseases: An Overview

For any biological response, transmission of extracellular signals to the nucleus is required for DNA transcription and gene expression. In that respect, cytokines/chemokines are well-known inflammatory agents which play a critical role in signalling pathways by activating the Janus kinase-signal transducers and activators of transcription (JAK-STAT) signalling proteins (Janus kinase-signal transducers and activators of transcription) which are a group of intracellular kinase molecules. Cytokines are a category of small proteins (∼5-25 kDa) that play a major role in cell signalling and are major drivers of an autoimmune response. Here we will discuss the role of Janus kinase-signal transducers and activators of transcription kinase cascades in the inflammatory-proliferative cascades of autoimmune disease and about the recent progress in the development of oral synthetic Janus kinase inhibitors (JAKi) and their therapeutic efficacies in dermatologic and systemic autoimmune diseases. Therapeutic efficacy of Janus kinase inhibitors is now well established in the treatment of array of autoimmune and inflammatory disease: spondylarthritis with a special focus on psoriatic arthritis (PsA) and its dermatologic manifestations (psoriasis) and ankylosing spondylitis (AS), atopic dermatitis (AD), alopecia areata (AA), rheumatoid arthritis (RA) and inflammatory bowel disease (IBD). In addition to the first-generation Janus kinase inhibitors several new-generation Janus kinase inhibitors are currently being evaluated. It is expected that these Janus kinase inhibitors likely have higher potency and less adverse effects as compared to their predecessors. Here we have discussed: (1) the functional significance of the Janus kinase-signal transducers and activators of transcription kinase cascades in the inflammatory-proliferative processes of autoimmune diseases and its cellular/molecular mechanisms and (2) progress in the development of oral synthetic Janus kinase inhibitors and their therapeutic efficacies in several systemic and cutaneous autoimmune diseases.

Current application status and structure-activity relationship of selective and non-selective JAK inhibitors in diseases

JAK kinase includes four family members: JAK1, JAK2, JAK3, and TYK2. It forms the JAK-STAT pathway with signal transmitters and activators of subscription (STAT). This pathway is one of the main mechanisms by which many cytokine receptors transduce intracellular signals, it is associated with the occurrence of various immune, inflammatory, and tumor diseases. JAK inhibitors block the signal transduction of the JAK-STAT pathway by targeting JAK kinase. Based on whether they target multiple subtypes of JAK kinase, JAK inhibitors are categorized into pan-JAK inhibitors and selective JAK inhibitors. Compared with pan JAK inhibitors, selective JAK inhibitors are associated with a specific member, thus more targeted in therapy, with improved efficacy and reduced side effects. Currently, a number of JAK inhibitors have been approval for disease treatment. This review summarized the current application status of JAK inhibitors that have been marketed, advances of JAK inhibitors currently in phase Ш clinical trials, and the structure-activity relationship of them, with an intention to provide references for the development of novel JAK inhibitors.

Risk of herpes zoster associated with JAK inhibitors in immune-mediated inflammatory diseases: a systematic review and network meta-analysis

Objective: Janus kinase (JAK) inhibitors are a novel class of drugs that have shown efficacy in treating immune-mediated inflammatory diseases (IMIDs). However, their safety profile in terms of herpes zoster infection remains unclear. We aimed to evaluate the risk of herpes zoster associated with JAK inhibitors in patients with IMIDs. Methods: A systematic search of electronic databases was conducted to identify randomized controlled trials (RCTs) that evaluated the safety of JAK inhibitors in patients with IMIDs including inflammatory bowel disease (IBD), rheumatoid arthritis (RA), spondyloarthritis (SpA), psoriasis (PsO), and psoriatic arthritis (PsA). The primary outcome of interest was the incidence of herpes zoster infection. Network meta-analysis was performed to compare the risk of herpes zoster among different JAK inhibitors and placebo. Results: A network meta-analysis was conducted using data from 47 RCTs including 24,142 patients. In patients with IMIDs, peficitinib 100 mg QD was associated with the highest risk of herpes zoster infection in patients with IMIDs, followed by baricitinib 4 mg QD and upadacitinib 30 mg QD. No difference in herpes zoster risk was found for other JAK inhibitors compared with placebo. Subgroup analysis indicated that higher incidence of herpes zoster was found in patients treated by baricitinib 4 mg QD, peficitinib 100 mg QD, and upadacitinib 30 mg QD only in patients with RA. Conclusion: Our study suggests that some JAK inhibitors, particularly peficitinib, baricitinib, and tofacitinib, are associated with a higher risk of herpes zoster infection in patients with IMIDs.

The holistic approach to psoriasis patients with comorbidities: the role of investigational drugs

INTRODUCTION

Psoriasis is a high-burden syndrome characterized by cutaneous and extracutaneous manifestations that profoundly reduce patients' quality of life. The presence of concomitant comorbidities often represents a limit to the most appropriate psoriasis treatment that will be overcome by the development of drugs effective for diseases with common pathogenetic pathways.

AREAS COVERED

The current review summarizes the latest findings on investigational drugs for psoriasis and their role on potentially concomitant diseases that share similar pathogenetic pathways.

EXPERT OPINION

The development of novel drugs that target key-molecules in the pathogenesis of several diseases, including psoriasis, will impact on the reduction of polypharmacy and drug interaction with increased patients' compliance to treatment, wellbeing and quality of life. Certainly, the efficacy and safety profile of each novel agent must be defined and evaluated in real-life, since the performance may vary according to comorbidities and their severity. Anyway, future is now, and research must continue in this direction.

Evolving cognition of the JAK-STAT signaling pathway: autoimmune disorders and cancer

The Janus kinase (JAK) signal transducer and activator of transcription (JAK-STAT) pathway is an evolutionarily conserved mechanism of transmembrane signal transduction that enables cells to communicate with the exterior environment. Various cytokines, interferons, growth factors, and other specific molecules activate JAK-STAT signaling to drive a series of physiological and pathological processes, including proliferation, metabolism, immune response, inflammation, and malignancy. Dysregulated JAK-STAT signaling and related genetic mutations are strongly associated with immune activation and cancer progression. Insights into the structures and functions of the JAK-STAT pathway have led to the development and approval of diverse drugs for the clinical treatment of diseases. Currently, drugs have been developed to mainly target the JAK-STAT pathway and are commonly divided into three subtypes: cytokine or receptor antibodies, JAK inhibitors, and STAT inhibitors. And novel agents also continue to be developed and tested in preclinical and clinical studies. The effectiveness and safety of each kind of drug also warrant further scientific trials before put into being clinical applications. Here, we review the current understanding of the fundamental composition and function of the JAK-STAT signaling pathway. We also discuss advancements in the understanding of JAK-STAT-related pathogenic mechanisms; targeted JAK-STAT therapies for various diseases, especially immune disorders, and cancers; newly developed JAK inhibitors; and current challenges and directions in the field.

JAK inhibition ameliorates bone destruction by simultaneously targeting mature osteoclasts and their precursors

BACKGROUND

Rheumatoid arthritis (RA) is characterized by chronic inflammation and resultant cartilage/bone destruction because of aberrantly activated osteoclasts. Recently, novel treatments with several Janus kinase (JAK) inhibitors have been shown to successfully ameliorate arthritis-related inflammation and bone erosion, although their mechanisms of action for limiting bone destruction remain unclear. Here, we examined the effects of a JAK inhibitor on mature osteoclasts and their precursors by intravital multiphoton imaging.

METHODS

Inflammatory bone destruction was induced by local injection of lipopolysaccharides into transgenic mice carrying reporters for mature osteoclasts or their precursors. Mice were treated with the JAK inhibitor, ABT-317, which selectively inhibits the activation of JAK1, and then subjected to intravital imaging with multiphoton microscopy. We also used RNA sequencing (RNA-Seq) analysis to investigate the molecular mechanism underlying the effects of the JAK inhibitor on osteoclasts.

RESULTS

The JAK inhibitor, ABT-317, suppressed bone resorption by blocking the function of mature osteoclasts and by targeting the migratory behaviors of osteoclast precursors to the bone surface. Further exhaustive RNA-Seq analysis demonstrated that Ccr1 expression on osteoclast precursors was suppressed in the JAK inhibitor-treated mice; the CCR1 antagonist, J-113863, altered the migratory behaviors of osteoclast precursors, which led to the inhibition of bone destruction under inflammatory conditions.

CONCLUSIONS

This is the first study to determine the pharmacological actions by which a JAK inhibitor blocks bone destruction under inflammatory conditions; this inhibition is beneficial because of its dual effects on both mature osteoclasts and immature osteoclast precursors.

Signaling pathways in rheumatoid arthritis: implications for targeted therapy

Rheumatoid arthritis (RA) is an incurable systemic autoimmune disease. Disease progression leads to joint deformity and associated loss of function, which significantly impacts the quality of life for sufferers and adds to losses in the labor force. In the past few decades, RA has attracted increased attention from researchers, the abnormal signaling pathways in RA are a very important research field in the diagnosis and treatment of RA, which provides important evidence for understanding this complex disease and developing novel RA-linked intervention targets. The current review intends to provide a comprehensive overview of RA, including a general introduction to the disease, historical events, epidemiology, risk factors, and pathological process, highlight the primary research progress of the disease and various signaling pathways and molecular mechanisms, including genetic factors, epigenetic factors, summarize the most recent developments in identifying novel signaling pathways in RA and new inhibitors for treating RA. therapeutic interventions including approved drugs, clinical drugs, pre-clinical drugs, and cutting-edge therapeutic technologies. These developments will hopefully drive progress in new strategically targeted therapies and hope to provide novel ideas for RA treatment options in the future.

Post hoc analysis of clinical characteristics of patients with radiographic progression in a Japanese phase 3 trial of peficitinib and methotrexate treatment (RAJ4)

OBJECTIVE

To determine the efficacy of peficitinib in reducing joint damage and predictive factors affecting treatment response in Japanese patients with rheumatoid arthritis.

METHODS

This post hoc analysis used data from a placebo-controlled, phase 3 trial (RAJ4) of peficitinib in patients with rheumatoid arthritis and inadequate response to methotrexate. Erosion and joint space narrowing (JSN) were assessed at baseline and at Week 28/early termination of treatment using the van der Heijde-modified Sharp method. A univariate logistic regression analysis of change from baseline in a modified total Sharp score identified predictive factors with significant treatment interaction; the effects of these factors on treatment response were further evaluated using a multivariate model.

RESULTS

The analyses included 481 patients. For most joint groups, peficitinib demonstrated a reduced change from baseline at Week 28/early termination in erosion and JSN scores versus placebo; a numerically greater effect was observed with peficitinib 150 mg versus 100 mg. Baseline C-reactive protein (CRP) and prednisolone dose were identified as clinically significant negative predictive factors: the treatment effect decreased as CRP or prednisolone dose increased for both peficitinib doses.

CONCLUSIONS

Peficitinib 100 mg and 150 mg reduced joint damage versus placebo, across almost all joint groups. Higher baseline CRP and/or prednisolone dose were associated with reduced peficitinib efficacy.

CLINICALTRIALS.GOV IDENTIFIER

NCT02305849.

Efficacy and safety of topical brepocitinib for the treatment of mild-to-moderate atopic dermatitis: a phase IIb, randomized, double-blind, vehicle-controlled, dose-ranging and parallel-group study

BACKGROUND

Atopic dermatitis (AD) is a prevalent inflammatory, pruritic skin disease. The Janus kinase (JAK) pathway is a treatment target.

OBJECTIVES

To assess the efficacy, safety and pharmacokinetics of topical cream brepocitinib, a small-molecule tyrosine kinase 2 (TYK2)/JAK1 inhibitor, in participants with mild-to-moderate AD.

METHODS

In this phase IIb, double-blind, dose-ranging study, participants were randomized to receive one of eight treatments for 6 weeks: brepocitinib 0·1% once daily (QD), 0·3% QD or twice daily (BID), 1·0% QD or BID, 3·0% QD, or vehicle QD or BID. The primary endpoint was the percentage change from baseline in the Eczema Area and Severity Index (EASI) total score at week 6. Adverse events (AEs) were monitored.

RESULTS

Overall, 292 participants were enrolled and randomized. The brepocitinib 1% QD and 1% BID groups achieved statistically significantly greater (with multiplicity-adjusted P < 0·05 due to Hochberg's step-up method) percentage reductions from baseline in EASI total score at week 6 [least squares mean (90% confidence interval, CI): QD: -70·1 (-82·1 to -58·0); BID: -75·0 (-83·8 to -66·2)] compared with respective vehicle [QD: -44·4 (-57·3 to -31·6); BID: -47·6 (-57·5 to -37·7)]. There was not a dose-dependent trend in AE frequency, and there were no serious AEs or deaths.

CONCLUSIONS

Topical brepocitinib is effective and well tolerated in participants with mild-to-moderate AD. What is already known about this topic? Janus kinase (JAK) inhibitors are in development for treatment of atopic dermatitis (AD). The tyrosine kinase 2 and JAK 1 inhibition by brepocitinib may bring a new profile for topical JAK inhibitors for treatment of mild-to-moderate AD. What does this study add? Topical brepocitinib can provide rapid, effective symptom reduction, and could offer a novel alternative to current topical treatments for mild-to-moderate AD.

JAK kinase inhibitors and varicella zoster virus infection in patients with rheumatoid arthritis. Systematic review of the literature

OBJECTIVES

JAK kinase inhibitors (JAKi) are a new therapeutic option in the treatment of rheumatoid arthritis, but they are not without risks, especially the incidence of herpes zoster (HZ).

MATERIAL AND METHODS

Systematic literature review that evaluates the incidence of HZ published in the clinical trials of the different JAK is marketed or under study.

RESULTS

The HZ rates ranged between 1.51 and 20.22. The results were expressed mainly as a percentage of events. The most recent studies better categorized the incidence of HZ and its severity.

CONCLUSION

JAK is are associated with an increased risk of HZ. Although the HZ rates of the selective JAK1 JAK is are lower, more studies are needed to confirm these results.

Advance in bone destruction participated by JAK/STAT in rheumatoid arthritis and therapeutic effect of JAK/STAT inhibitors

Rheumatoid arthritis (RA) is an autoimmune disease characterized by chronic joint inflammation and bone erosion. The bones in the human body are constantly undergoing bone remodeling throughout their lives, which is the process of bone resorption by osteoclasts to damaged bone tissue and new bone formation by osteoblasts. Osteoblasts (OBs) are the main functional cells in bone formation, responsible for the synthesis, secretion and mineralization of the bone matrix. On the contrary, osteoclasts (OCs) mediate bone breakdown during natural bone turnover, but excessive breakdown occurs in RA. Under the condition of RA inflammation, many molecules, such as IL-1β, IL-6, TNF-α, IL-17 and hypoxia-inducible factor-1α (HIF-1α) are produced that could mediate bone loss. Studies have shown that cytokines mainly promote the formation of OCs and play a role in bone resorption by stimulating OBs to express receptor activator of NF-κB ligand (RANKL). JAK/STAT plays a crucial role in the process of bone destruction. And JAK/STAT pathway mediates the RANKL/receptor activator of NF-κB (RANK)/osteoprotegerin (OPG) axis. Tofacitinib, Baricitinib, Peficitinib and Filgotinib are now being used in patients with moderate to severe RA, as well as in patients with RA who have an inadequate response to methotrexate therapy and bone destruction. Currently, Tofacitiniband Baritinib areapprovedfor thetreatmentof moderate-to-severely active RA. JAK inhibitors have been reported to have better efficacy and lower adverse effects compared with methotrexate and adalimumab. In addition, two JAK inhibitors are currently in development: the JAK1 selective Upadacitinib, and the JAK3 selective inhibitor Decernotinib. In addition to the above JAK inhibitors, some small molecular compounds inhibit bone destruction by inhibiting the Phosphorylation of STAT3. In this paper, the research progress of bone destruction participated by JAK/ STAT in rheumatoid arthritis and therapeutic effect of JAK/STAT inhibitors were reviewed.

Efficacy and Safety of JAK Inhibitors for Rheumatoid Arthritis: A Meta-Analysis

Background: More and more trials have been conducted. We aimed to assess the efficacy and safety of different JAKinibs in RA. Methods: A systematic search of randomized controlled trials (RCTs) with JAKinib treatment in RA published in the Medline, Embase, and Cochrane databases up to May 2021 was performed. Results: 37 trials involving 15,174 patients were identified. Pooled analysis revealed that JAKinibs were associated with significant therapeutic improvement in RA patients as determined by ACR20 (RR = 2.03, 95% CI: 1.85 to 2.28) and HAQ-DI (MD = −0.31, 95% CI: −0.33 to −0.28) over placebo. Compared to placebo, JAKinib treatment was also associated with more adverse events (RR = 1.10, p < 0.001; RR = 1.29, p < 0.001; RR = 1.59, p = 0.02). Baricitinib and upadacitinib were related to more frequent adverse events (RR = 1.10; 95% CI: 1.01, 1.21; RR = 1.19; 95% CI: 1.11, 1.28) and infection (RR = 1.22; 95% CI: 1.09, 1.37; RR = 1.38; 95% CI: 1.22, 1.56), whereas only baricitinib was associated with more herpes zoster (RR = 3.15; 95% CI: 1.19, 8.33). Conclusions: JAKinibs were superior to placebo for improving signs, symptoms, and health-related quality of life in RA patients at short term, whereas the overall risk of adverse events and infections were greater with baricitinib and upadacitinib, and a higher risk of herpes zoster was only associated with baricitinib. More trials are needed to investigate the long-term safety.

Pharmacokinetics and Safety of Single and Multiple Doses of Peficitinib (ASP015K) in Healthy Chinese Subjects

Objective

To investigate the pharmacokinetics and safety of peficitinib (Janus kinase inhibitor for the treatment of rheumatoid arthritis) in healthy Chinese subjects following single and multiple doses.

Methods

This open-label, randomized study was conducted at one site in China. Subjects received peficitinib 50, 100 or 150 mg as a single dose on Day 1 (fasted) and once daily from Days 8 to 13 in the multiple-dose period (fed). Blood samples were collected before administration each day, and up to 72h post administration. Pharmacokinetic assessments included area under the concentration curve (AUC), half-life (t_1/2), maximum concentration (C_max), and time to maximum concentration (t_max) of peficitinib and its metabolites (H1, H2 and H4). Treatment-emergent adverse events (TEAEs) were evaluated.

Results

Thirty-six subjects were enrolled (12 per dose group). After a single dose of peficitinib, median t_max was 1.0–1.5h and mean t_1/2 was 7.4–13.0h for all doses. In the multiple-dose period, median t_max was 1.5–2.0h. Dose-proportional increases in C_max and AUC_24h were observed for peficitinib and its metabolites following single and multiple doses, with minimal drug accumulation. The major metabolite was H2, with a systemic exposure of >150% of the parent AUC. Drug-related TEAEs were experienced by 5 (13.9%) and 12 (33.3%) subjects in the single- and multiple-dose periods, respectively. Following multiple doses of peficitinib, TEAEs were more frequent in higher than lower dose groups but were mild in severity with no related discontinuation or death.

Conclusion

Following single and multiple doses of peficitinib in healthy Chinese subjects, peficitinib demonstrated rapid absorption and was well tolerated at all doses.

Clinicaltrials.gov Identifier

NCT04143477.

Targeting Janus Kinase (JAK) for Fighting Diseases: The Research of JAK Inhibitor Drugs

Janus Kinase (JAK), a nonreceptor protein tyrosine kinase, has emerged as an excellent target through research and development since its discovery in the 1990s. As novel small-molecule targeted drugs, JAK inhibitor drugs have been successfully used in the treatment of rheumatoid arthritis (RA), myofibrosis (MF) and ulcerative colitis (UC). With the gradual development of JAK targets in the market, JAK inhibitors have also received very considerable feedback in the treatment of autoimmune diseases such as atopic dermatitis (AD), Crohn's disease (CD) and graft-versus host disease (GVHD). This article reviews the research progress of JAK inhibitor drugs: introducing the existing JAK inhibitors on the market and some JAK inhibitors in clinical trials currently. In addition, the synthesis of various types of JAK inhibitors were summarized, and the effects of different drug structures on drug inhibition and selectivity.

Identification of a Novel 2,8-Diazaspiro[4.5]decan-1-one Derivative as a Potent and Selective Dual TYK2/JAK1 Inhibitor for the Treatment of Inflammatory Bowel Disease

In this study, we described a series of 2,8-diazaspiro[4.5]decan-1-one derivatives as selective TYK2/JAK1 inhibitors. Systematic exploration of the structure-activity relationship through the introduction of spirocyclic scaffolds based on the reported selective TYK2 inhibitor 14l led to the discovery of the superior derivative compound 48. Compound 48 showed excellent potency on TYK2/JAK1 kinases with IC₅₀ values of 6 and 37 nM, respectively, and exhibited more than 23-fold selectivity for JAK2. Compound 48 also demonstrated excellent metabolic stability and more potent anti-inflammatory efficacy than tofacitinib in acute ulcerative colitis models. Moreover, the excellent anti-inflammatory effect of compound 48 was mediated by regulating the expression of related TYK2/JAK1-regulated genes, as well as the formation of Th1, Th2, and Th17 cells. Taken together, these findings suggest that compound 48 is a selective dual TYK2/JAK inhibitor, deserving to be developed as a clinical candidate.

Janus Kinase Inhibitors Improve Disease Activity and Patient-Reported Outcomes in Rheumatoid Arthritis: A Systematic Review and Meta-Analysis of 24,135 Patients

Pain, fatigue, and physical activity are major determinants of life quality in rheumatoid arthritis (RA). Janus kinase (JAK) inhibitors have emerged as effective medications in RA and have been reported to exert direct analgesic effect in addition to reducing joint inflammation. This analysis aims to give an extensive summary of JAK inhibitors especially focusing on pain and patient reported outcomes (PRO). MEDLINE, CENTRAL, Embase, Scopus, and Web of Science databases were searched on the 26 October 2020, and 50 randomized controlled trials including 24,135 adult patients with active RA met the inclusion criteria. JAK inhibitors yielded significantly better results in all 36 outcomes compared to placebo. JAK monotherapy proved to be more effective than methotrexate in 9 out of 11 efficacy outcomes. In comparison to biological disease-modifying antirheumatic drugs, JAK inhibitors show statistical superiority in 13 of the 19 efficacy outcomes. Analgesic effect determined using the visual analogue scale and American College of Rheumatology (ACR) 20/50/70 response rates was significantly greater in the JAK group in all comparisons, and no significant difference regarding safety could be explored. This meta-analysis gives a comprehensive overview of JAK inhibitors and provides evidence for their superiority in improving PROs and disease activity indices in RA.

The Janus kinase inhibitor (baricitinib) suppresses the rheumatoid arthritis active marker gliostatin/thymidine phosphorylase in human fibroblast-like synoviocytes

Gliostatin/thymidine phosphorylase (GLS/TP) is known to have angiogenic and arthritogenic activities in the pathogenesis of rheumatoid arthritis (RA). The novel oral Janus kinase (JAK) inhibitor baricitinib has demonstrated high efficacy in RA. However, the effect of baricitinib on fibroblast-like synoviocytes (FLSs), a key component of invasive synovitis, has not been still elucidated. This study investigated whether GLS/TP production could be regulated by JAK/signal transducers and activators of transcription (STAT) signaling in FLSs derived from patients with RA. FLSs were cultured and stimulated by interferon (IFN)γ in the presence of baricitinib. Expression levels of GLS/TP were determined using reverse transcription-polymerase chain reaction (RT-PCR), enzyme-linked immunosorbent assay (ELISA), and immunocytochemistry. Phosphorylation of STAT proteins was investigated by Western blot. In cultured FLSs, GLS/TP mRNA and protein levels were significantly induced by treatment with IFNγ and these inductions were suppressed by baricitinib treatment. Baricitinib inhibited IFNγ-induced STAT1 phosphorylation, while JAK/STAT activation played a pivotal role in IFNγ-mediated GLS/TP upregulation in RA. These results suggested that baricitinib suppressed IFNγ-induced GLS/TP expression by inhibiting JAK/STAT signaling, resulting in the attenuation of neovascularization, synovial inflammation, and cartilage destruction.

Effect of JAK inhibitors on high- and low-density lipoprotein in patients with rheumatoid arthritis: a systematic review and network meta-analysis

OBJECTIVES

Janus kinase (JAK) inhibitors are a new class of medication for treatment of rheumatoid arthritis (RA), and such inhibitors alter levels of high-density lipoprotein (HDL) and low-density lipoprotein (LDL) in RA patients. However, the extent of such changes has not been systematically reviewed.

METHOD

A systematic review and network meta-analysis was performed on randomized trials in RA patients in response to JAKi identified from Pubmed, Medline, Embase, and Cochrane Controlled Trials Register. The primary outcome was mean change of HDL-C and LDL-C from baseline. Mean treatment differences and the rank of the effect of various JAKi on HDL-C and LDL-C were estimated.

RESULTS

Based on data from 18 unique studies involving five approved JAK inhibitors and 6697 RA patients (JAKi = 3341, placebo = 3356), such inhibitors led to a mean increase of 8.11 mg/dl (95% CI 6.65-9.58, I² = 82%) in HDL levels from baseline, and a mean increase of 11.37 mg/dl (95% CI 7.84-14.91, I² = 88%) in LDL levels from baseline. Cardiovascular disease risk did not differ significantly between patients who received JAK inhibitors or those who received placebo or active agents.

CONCLUSIONS

Our analysis suggests that, at their recommended doses, all five JAK inhibitors lead to an increase in HDL and LDL levels in RA patients. Further long-term research is required to extend these results and understand whether changes in lipid levels in RA patients can affect cardiovascular risk. Key Points • This is the first systematic review and NMA examining the effect of all five clinically approved JAK inhibitors on lipid levels in RA patients. • Recommended doses of JAK inhibitors used for the treatment of RA patients can induce a significant increase in HDL and LDL levels. • Indirect pairwise comparisons suggest that only upadacitinib and peficitinib have significantly different ability to induce LDL change in RA patients.

Efficacy of peficitinib in two patients with rheumatoid arthritis on maintenance hemodialysis

Objective: Treatment options for patients with rheumatoid arthritis on maintenance hemodialysis with an inadequate response to biologic agents have not been reported. In this report, we describe two patients who achieved remission after treatment with peficitinib.

Methods: Two 69- and 85-year-old patients with rheumatoid arthritis on maintenance hemodialysis were previously treated with biologics and started on peficitinib 100 mg/day after the secondary failure of biologics.

Discussion: In the two cases presented here, rheumatoid arthritis was almost in remission and there were no adverse events, although the patients were switched to peficitinib after secondary failure of the biologic agents. Among Janus kinase inhibitors, peficitinib has the lowest renal excretion; therefore, its administration in patients on dialysis is not contraindicated according to the package insert in Japan. The use of biologic agents in patients on hemodialysis has been reported to be associated with a high incidence of infections; therefore, care should be taken to avoid infections when administering Janus kinase inhibitors.

Conclusion: Janus kinase inhibitors with low renal excretion, such as peficitinib, may be effective in patients with rheumatoid arthritis on maintenance hemodialysis who have an inadequate response to biologic agents.

A Decade of JAK Inhibitors: What Have We Learned and What May Be the Future?

The discovery of cytokines and their role in immune and inflammatory disease led to the development of a plethora of targeted biologic therapies. Later, efforts to understand mechanisms of cytokine signal transduction led to the discovery of JAKs, which themselves were quickly identified as therapeutic targets. It has been a decade since the first JAK inhibitors (jakinibs) were approved, and there are now 9 jakinibs approved for the treatment of rheumatic, dermatologic, hematologic, and gastrointestinal indications, along with emergency authorization for COVID-19. In this review, we will summarize relevant discoveries that led to first-generation jakinibs and review their efficacy and safety as demonstrated in pivotal clinical studies. We will discuss the next generation of more selective jakinibs, along with agents that target kinase families beyond JAKs. Finally, we will reflect on both the opportunities and challenges ahead as we enter the second decade of the clinical use of jakinibs.

Recommendations of the Brazilian Society of Rheumatology for the use of JAK inhibitors in the management of rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic and autoimmune systemic inflammatory disease that can cause irreversible joint deformities, with increased morbidity and mortality and a significant impact on the quality of life of the affected individual. The main objective of RA treatment is to achieve sustained clinical remission or low disease activity. However, up to 40% of patients do not respond to available treatments, including bDMARDs. New therapeutic targets for RA are emerging, such as Janus kinases (JAKs). These are essential for intracellular signaling (via JAK-STAT) in response to many cytokines involved in RA immunopathogenesis. JAK inhibitors (JAKi) have established themselves as a highly effective treatment, gaining increasing space in the therapeutic arsenal for the treatment of RA. The current recommendations aim to present a review of the main aspects related to the efficacy and safety of JAKis in RA patients, and to update the recommendations and treatment algorithm proposed by the Brazilian Society of Rheumatology in 2017.

Management of Rheumatoid Arthritis: An Overview

Rheumatoid arthritis (RA) is a multifactorial autoimmune disease of unknown etiology, primarily affecting the joints, then extra-articular manifestations can occur. Due to its complexity, which is based on an incompletely elucidated pathophysiological mechanism, good RA management requires a multidisciplinary approach. The clinical status of RA patients has improved in recent years due to medical advances in diagnosis and treatment, that have made it possible to reduce disease activity and prevent systemic complications. The most promising results were obtained by developing disease-modifying anti-rheumatic drugs (DMARDs), the class to which conventional synthetic, biologic, and targeted synthetic drugs belong. Furthermore, ongoing drug development has led to obtaining molecules with improved efficacy and safety profiles, but further research is needed until RA turns into a curable pathology. In the present work, we offer a comprehensive perspective on the management of RA, by centralizing the existing data provided by significant literature, emphasizing the importance of an early and accurate diagnosis associated with optimal personalized treatment in order to achieve better outcomes for RA patients. In addition, this study suggests future research perspectives in the treatment of RA that could lead to higher efficacy and safety profiles and lower financial costs.

How effective are JAK-inhibitors? Perspectives from clinical trials and real-world studies

INTRODUCTION

JAK-inhibitors have emerged as a new treatment option for rheumatoid arthritis, with five molecules currently available in different parts of the world: tofacitinib, baricitinib, upadacitinib, peficitinib, and filgotinib. These molecules have been the subject of numerous trials looking at their efficacy (how well they perform in controlled conditions) but also some observational studies from the general population to assess their effectiveness (how well treatment perform under real conditions). With each their own weaknesses and strengths, they give different but complementary information.

AREAS COVERED

We will review what we can learn from trials and real-world studies on how effective JAK-inhibitors are in the treatment of rheumatoid arthritis.

EXPERT OPINION

Trials of JAK-inhibitors have shown that JAK-inhibitors are efficacious for the treatment of rheumatoid arthritis. However, their main outcomes are not clinically meaningful as their aim is mainly the regulatory authorization of the product. Real-world studies are important as they evaluate the real-life effectiveness of the compounds, however, they are scarce at the moment, mainly evaluating tofacitinib and of variable quality. Future high-quality studies are needed to assess the real-world effectiveness of JAK-inhibitors in a more complete manner.

Cytokine Networks in the Pathogenesis of Rheumatoid Arthritis

Rheumatoid arthritis (RA) is an autoimmune disease characterized by chronic systemic inflammation causing progressive joint damage that can lead to lifelong disability. The pathogenesis of RA involves a complex network of various cytokines and cells that trigger synovial cell proliferation and cause damage to both cartilage and bone. Involvement of the cytokines tumor necrosis factor (TNF)-α and interleukin (IL)-6 is central to the pathogenesis of RA, but recent research has revealed that other cytokines such as IL-7, IL-17, IL-21, IL-23, granulocyte macrophage colony-stimulating factor (GM-CSF), IL-1β, IL-18, IL-33, and IL-2 also play a role. Clarification of RA pathology has led to the development of therapeutic agents such as biological disease-modifying anti-rheumatic drugs (DMARDs) and Janus kinase (JAK) inhibitors, and further details of the immunological background to RA are emerging. This review covers existing knowledge regarding the roles of cytokines, related immune cells and the immune system in RA, manipulation of which may offer the potential for even safer and more effective treatments in the future.

JAK-STAT signaling in human disease: From genetic syndromes to clinical inhibition

Since its discovery, the Janus kinase-signal transduction and activation of transcription (JAK-STAT) pathway has become recognized as a central mediator of widespread and varied human physiological processes. The field of JAK-STAT biology, particularly its clinical relevance, continues to be shaped by 2 important advances. First, the increased use of genomic sequencing has led to the discovery of novel clinical syndromes caused by mutations in JAK and STAT genes. This has provided insights regarding the consequences of aberrant JAK-STAT signaling for immunity, lymphoproliferation, and malignancy. In addition, since the approval of ruxolitinib and tofacitinib, the therapeutic use of JAK inhibitors (jakinibs) has expanded to include a large spectrum of diseases. Efficacy and safety data from over a decade of clinical studies have provided additional mechanistic insights while improving the care of patients with inflammatory and neoplastic conditions. This review discusses major advances in the field, focusing on updates in genetic diseases and in studies of clinical jakinibs in human disease.

A pooled analysis of serious infections and herpes zoster-related disease in Asian patients with rheumatoid arthritis treated with peficitinib (ASP015K) over a median of 3 years

OBJECTIVE

To analyse serious infection (SI) and herpes zoster-related disease (HZD) during long-term treatment of rheumatoid arthritis with the oral Janus kinase inhibitor, peficitinib (ASP015K).

METHODS

This was a post hoc analysis of pooled data from one Phase 2b study and two Phase 3 studies and final data from a long-term extension study of peficitinib in Asian rheumatoid arthritis patients. Two pooled datasets were analysed (Phase 3 studies and Phase 2/3 studies). Univariate and multivariate Cox regression analyses explored relationships between exposure-adjusted incidence rate of SI and HZD, peficitinib dose, and baseline factors.

RESULTS

Total peficitinib exposure for 1052 patients receiving once-daily peficitinib in the pooled Phase 2/3 Asian studies was 2998.9 patient-years. Exposure-adjusted incidence rates (95% confidence interval) of SI and HZD were 2.7 (2.2, 3.4) and 6.9 (6.0, 8.0) per 100 patient-years, respectively, in pooled Phase 2/3 studies. Advanced age was prognostic for SI and HZD, while baseline prednisolone dose was prognostic for SI. There was no temporal relationship between either adverse event and prolonged peficitinib administration.

CONCLUSIONS

As expected in this peficitinib-treated population, older patients had increased risk of SI and HZD, and those receiving higher prednisolone doses had increased risk of SI.

Targeting the JAK-STAT pathway in autoimmune diseases and cancers: A focus on molecular mechanisms and therapeutic potential

The Janus kinase (JAK)/signal transducer and activator of transcription (STAT) signaling pathway is characterized by diverse immune regulatory systems involving cell proliferation, survival, and inflammation and immune tolerance. Aberrant JAK/STAT transduction activates proinflammatory cytokine signaling that jeopardize the immune balance and thus contributes to the development of autoimmune diseases and cancer progression. The success of several small-molecule JAK inhibitors in the treatment of rheumatologic diseases demonstrates that targeting the JAK/STAT pathway is efficient in suppressing inflammation and sheds light on their therapeutic potential in several autoimmune diseases and cancers. In this review, we discuss the signal transduction and molecular mechanism involving immune function through the JAK-STAT pathway, outline the role of this pathway in autoimmunity and oncoimmunology, and explain the preclinical and clinical trial evidence for the therapeutic potential of targeting the JAK-STAT signaling pathway. Issues regarding the safety and clinical efficacy of JAK inhibitors are reviewed. Ongoing studies are addressed with a focus on emerging indications for JAK inhibition and explanations of the novel mechanisms of JAK-STAT signaling blockade.

Impact of age on the efficacy and safety of peficitinib (ASP015K) for the treatment of rheumatoid arthritis

OBJECTIVES

To evaluate peficitinib efficacy and safety in Asian patients with rheumatoid arthritis (RA), stratified by age (≥20-<50, ≥50-<65, and ≥65 years).

METHODS

Efficacy data from two Phase 3 studies were analysed. Safety data from one Phase 2, two Phase 3, and one open-label extension study were pooled. Incidence rates per 100 patient-years of adverse events of special interest were calculated, and Cox proportional hazard analysis was conducted.

RESULTS

1052 patients received peficitinib for 2 years (median). Peficitinib demonstrated efficacy improvements versus placebo across all age categories. Incidence rates (95% confidence interval) per 100 patient-years for ≥20-<50, ≥50-<65, and ≥65 years were 0.8 (0.4, 1.9), 2.6 (1.8, 3.7), and 4.7 (3.1, 7.0) for serious infections and 3.7 (2.5, 5.4), 6.4 (5.0, 8.2), and 11.2 (8.5, 14.7) for herpes zoster-related disease, respectively. Twenty patients reported malignancies in pooled Phase 2/3 studies. Incidences of serious infections and herpes zoster-related disease increased significantly with age, but there was no association with baseline estimated glomerular filtration rate.

CONCLUSIONS

Peficitinib was efficacious in adult Asian RA patients of all ages. Age, but not estimated glomerular filtration rate, was associated with serious infections and herpes zoster-related disease, demonstrating the importance of an appropriate RA treatment strategy in older patients.

The role for JAK inhibitors in the treatment of immune-mediated rheumatic and related conditions

JAK inhibitors (JAKIs) are a new class of targeted therapy that have entered clinical practice for the treatment of immune-mediated rheumatic conditions. JAKIs can block the signaling activity of a variety of proinflammatory cytokines and therefore have the potential to mediate therapeutic benefits across a wide range of immune-mediated conditions. Several JAKIs are licensed, and many more are undergoing clinical trials. Here we provide a narrative review of the current and upcoming JAKIs for adult immune-mediated rheumatic and related conditions, with a specific focus on efficacy in rheumatoid arthritis, psoriatic arthritis, axial spondyloarthritis, psoriasis, and inflammatory bowel disease. The overall safety profile of JAKIs appears largely comparable to that of existing biologic cytokine-targeting agents, particularly, TNF inhibitors, apart from risk of herpes zoster, which is increased for JAKIs. Importantly however, unresolved safety concerns remain, particularly relating to increased venous thromboembolism.

Patient- and physician-reported outcomes from two phase 3 randomized studies (RAJ3 and RAJ4) of peficitinib (ASP015K) in Asian patients with rheumatoid arthritis

BACKGROUND

Peficitinib (ASP015K), a novel oral Janus kinase inhibitor, has demonstrated efficacy and safety in the treatment of patients with rheumatoid arthritis (RA). This study evaluated the effect of peficitinib on patient- and physician-reported outcomes in Asian patients with RA and an inadequate response to prior disease-modifying antirheumatic drugs (DMARDs).

METHODS

Patients from two randomized, placebo-controlled, double-blind, phase 3 trials (RAJ3 and RAJ4) received once-daily peficitinib 100 mg, peficitinib 150 mg, or placebo, alone or in combination with DMARDs (RAJ3), or in combination with methotrexate (RAJ4). Mean changes in Work Productivity and Activity Impairment (WPAI) questionnaire domain scores from baseline, and percentages of patients achieving minimal clinically important differences (MCIDs) for patient- and physician-reported outcomes (WPAI, Health Assessment Questionnaire - Disability Index [HAQ-DI], and Subject's Global Assessment of Pain [SGAP]), and Physician's Global Assessment of disease activity (PGA) were evaluated at weeks 4, 8, 12, and 12/early termination (ET).

RESULTS

Data from 1025 patients were analyzed. At week 12/ET in both studies, patients who received peficitinib 100 mg or 150 mg reported significantly improved WPAI domain scores from baseline (except for absenteeism in RAJ4) compared with placebo (both doses, p<0.05). A higher proportion of peficitinib- versus placebo-treated patients achieved MCID in WPAI, HAQ-DI, SGAP, and PGA in studies RAJ3 and RAJ4. Significant differences with peficitinib versus placebo were evident in both studies as early as week 4 in HAQ-DI (peficitinib 150 mg only), SGAP, and PGA, and week 8 in WPAI loss of work productivity and daily activity impairment. At week 12/ET, significantly higher proportions of patients receiving peficitinib versus placebo achieved MCID in HAQ-DI, SGAP, PGA, and WPAI domains of presenteeism (RAJ3 only), loss of work productivity (RAJ3 only), and daily activity impairment (p<0.05 for all comparisons).

CONCLUSIONS

Peficitinib 100 mg or 150 mg administered daily over 12 weeks resulted in clinically meaningful improvements in outcomes that are important to RA patients, including pain, physical function, and work productivity and activity. These observations were reinforced through similar improvements in physicians' rating of disease activity.

TRIAL REGISTRATION

RAJ3: ClinicalTrials.gov, NCT02308163 , registered 4 December 2014. RAJ4: ClinicalTrials.gov, NCT02305849 , registered 3 December 2014.

Emerging protein kinase inhibitors for the treatment of rheumatoid arthritis

INTRODUCTION

Protein tyrosine kinase inhibitors are emergent drugs in the treatment of rheumatoid arthritis (RA); they block the signal transduction in immune cells preventing the production and release of pro-inflammatory cytokines.

AREAS COVERED

The current research aims to review the role of Janus, Bruton's and spleen kinase inhibitors for the treatment of RA. Mechanism of action, rationale for usage, and the main efficacy and safety outcomes in phase II and III clinical trials are described.

EXPERT OPINION

In RA, the development of Bruton kinase inhibitors was interrupted because they failed to demonstrate superiority versus placebo. The spleen kinase inhibitors had their development deprioritized because their risk/benefit profile was unfavorable compared to janus kinase inhibitors (JAKi). JAKi proved to be effective in treatment naïve patients and in those with previous failure to methotrexate and/or biological therapy. There still remain important points about JAKi that need more studies: the clinical importance of JAKi selectivity should be further evaluated in head-to-head trials and the safety profile of JAKi, mainly regarding the risk of malignancy and thromboembolic events, must be analyzed in long-term real-life studies.

Recent advances on signaling pathways and their inhibitors in rheumatoid arthritis

Rheumatoid arthritis (RA) is characterized by systemic synovitis leading to joint destruction in which imbalances in pro-inflammatory and anti-inflammatory cytokines promote the induction of autoimmunity. Some pro-inflammatory cytokines can trigger the signaling pathways which responsible for immune-mediated inflammation in RA, and the activated signaling pathways produce pro-inflammatory cytokines, resulting in aggravation of RA. Hence, understanding of the signaling pathways and their inhibitors might be advantageous in the development of therapeutic targets and new drugs for RA. In the current review, we summarize the signaling pathways involved in the pathogenesis of RA as well as the potential role of specific inhibitors in its management. We hope this paper may serve a reference for future studies on signaling pathways implicated in the pathogenesis of RA and benefit the treatment of RA.

Janus Kinase Inhibitors and Risk of Venous Thromboembolism: A Systematic Review and Meta-analysis

OBJECTIVE

To assess the risk of venous thromboembolism (VTE) in patients treated with Janus kinase (JAK) inhibitors in clinical trials.

PATIENTS AND METHODS

We performed a literature search of Ovid MEDLINE and ePub Ahead of Print, In-Process & Other Non-Indexed Citations, and Daily; Ovid EMBASE; Ovid Cochrane Central Register of Controlled Trials; Ovid Cochrane Database of Systematic Reviews; and Scopus, from inception to December 4, 2019, for randomized, placebo-controlled trials with JAK inhibitors as an intervention and reported adverse events. Odds ratio with 95% CI was calculated to estimate the VTE risk using a random effects model. Two independent reviewers screened and extracted data. The GRADE (Grading of Recommendations Assessment, Development and Evaluation) approach was used to assess certainty in estimated VTE risk.

RESULTS

We included 29 trials (13,910 patients). No statistically significant association was found between use of JAK inhibitors and risk of VTE (odds ratio, 0.91; 95% CI, 0.57 to 1.47; P=.70; I²=0; low certainty because of serious imprecision). Results using Bayesian analysis were consistent with those of the primary analysis. Results of stratified and meta-regression analyses suggested no interaction by dose of drug, indication for treatment, or length of follow-up.

CONCLUSION

We found insufficient evidence to support an increased risk of JAK inhibitor-associated VTE based on currently available data.

Type I Interferons in the Pathogenesis and Treatment of Autoimmune Diseases

Type I interferons (IFN-Is) are a very important group of cytokines that are produced by innate immune cells but also act on adaptive immune cells. IFN-Is possess antiviral, antitumor, and anti-proliferative effects, as well are associated with the initiation and maintenance of autoimmune disorders. Studies have shown that aberrantly expressed IFN-Is and/or type I IFN-inducible gene signatures in the serum or tissues of patients with autoimmune disorders are linked to their pathogenesis, clinical manifestations, and disease activity. Type I interferonopathies with mutations in genes impacting the type I IFN signaling pathway have shown symptoms and characteristics similar to those of systemic lupus erythematosus (SLE). Furthermore, both interventions in animal models and clinical trials of therapies targeting the type I IFN signaling pathway have shown efficacy in the treatment of autoimmune diseases. Our review aims to summarize the functions and targeted therapies (as well as clinical trials) of IFN-Is in both adult and pediatric autoimmune diseases, such as SLE, pediatric SLE (pSLE), rheumatoid arthritis (RA), juvenile idiopathic arthritis (JIA), juvenile dermatomyositis (JDM), Sjögren syndrome (SjS), and systemic sclerosis (SSc), discussing the potential abnormal regulation of transcription factors and epigenetic modifications and providing a potential mechanism for pathogenesis and therapeutic strategies for future clinical use.