Upadacitinib and filgotinib: the role of JAK1 selective inhibition in the treatment of rheumatoid arthritis

Drug Delivery Approaches for Rheumatoid Arthritis: Recent Advances and Clinical Translation Aspects

Rheumatoid arthritis (RA) is a multifactorial autoimmune disease characterized with symmetrical progression of joint deformity that is often diagnosed at a chronic condition with other associated pathological conditions such as pericarditis, keratitis, pulmonary granuloma. Despite the understanding of RA pathophysiology in disease progression, current clinical treatment options such as disease-modifying anti-rheumatic drugs (DMARDs), biologics, steroids, and non-steroidal anti-inflammatory drugs (NSAIDs) provide only palliative therapy while causing adverse side effects such as off-target multi-organ toxicity and risk of infections. Further, available drug delivery strategies to treat RA pathogenicity does not successfully reach the site of action due to various barriers such as phagocytosis and first pass effect in addition to the disease complexity and unknown etiology, thereby leading to the development of irreversible joint dysfunction. Therefore, novel and effective strategies remain an unmet need to control the disease progression and to maintain the balance between pro- and anti-inflammatory cytokines. This review provides a comprehensive outlook on the RA pathophysiology and its corresponding disease progression. Contributions of synoviocytes such as macrophages, fibroblast-like cells in increasing invasiveness to exacerbate joint damage is also outlined in this review, which could be a potential future therapeutic target to complement the existing treatment regimens in controlling RA pathogenesis. Further, various smart drug delivery approaches under research to achieve maximum therapeutic efficacy with minimal adverse side effects have been discussed, which in turn emphasize the unmet challenges and future perspectives in addressing RA complications.

[Small Molecule Therapy for Inflammatory Bowel Disease: JAK Inhibitors and S1PR Modulators]

Small molecules, including Janus kinase (JAK) inhibitors and sphingosine-1-phosphate receptor modulators (S1PRMs), are promising new treatments for inflammatory bowel disease (IBD). Small molecules exhibit more predictable pharmacokinetics than biologics, are less likely to induce immune responses, and can be administered orally. JAK inhibitors function by blocking the activity of JAK enzymes, which prevents the subsequent phosphorylation and activation of signal transducer and activator of transcription (STAT) proteins. Tofacitinib and filgotinib are approved for treating ulcerative colitis (UC), while upadacitinib is approved for UC and Crohn's disease. Nevertheless, JAK inhibitors can increase the risk of herpes zoster, cancer, major adverse cardiovascular events, and venous thromboembolism. S1PRMs bind to S1PRs, particularly S1PR1, on lymphocytes. This interaction inhibits lymphocytes from exiting the lymph nodes and migrating to the gut, thereby reducing inflammation and the immune response in the intestinal mucosa. Ozanimod and etrasimod are S1PRMs approved for the treatment of UC, but they can cause side effects such as bradycardia, conduction disorder, and macular edema. Overall, JAK inhibitors and S1PRMs offer significant benefits in managing IBD, although their potential side effects require careful monitoring.

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

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

Revisiting Structure-activity Relationships: Unleashing the potential of selective Janus kinase 1 inhibitors

Janus kinases (JAKs), a kind of non-receptor tyrosine kinases, the function has been implicated in the regulation of cell proliferation, differentiation and apoptosis, immune, inflammatory response and malignancies. Among them, JAK1 represents an essential target for modulating cytokines involved in inflammation and immune function. Rheumatoid arthritis, atopic dermatitis, ulcerative colitis and psoriatic arthritis are areas where approved JAK1 drugs have been applied for the treatment. In the review, we provided a brief introduction to JAK1 inhibitors in market and clinical trials. The structures of high active JAK1 compounds (IC50 ≤ 0.1 nM) were highlighted, with primary focus on structure-activity relationship and selectivity. Moreover, the druggability processes of approved drugs and high active compounds were analyzed. In addition, the issues involved in JAK1 compounds clinical application as well as strategies to surmount these challenges, were discussed.

Efficacy and Safety of Filgotinib in Rheumatoid Arthritis Patients Aged over and under 65 Years (ENANTIA-65)

BACKGROUND

According to recent data, the age of patients could represent an important risk factor for MACE (major cardiovascular events), cancer, and VTE (venous thromboembolism) during treatment with JAK inhibitors in rheumatoid arthritis. We decided to analyze the population involved in the ReLiFiRa study by identifying two groups of patients: 65 years or more and less than 65 years of age, evaluating the efficacy and tolerability of 200 mg of Filgotinib daily.

METHODS

Of the 120 ReLiFiRa patients, 54 were younger than 65 years old and 66 patients were 65 years old or older. The data of efficacy and tolerability of treatment with FIL 200 mg daily for 6 months were evaluated.

RESULTS

After six months of treatment, FIL was effective in both age groups. In both groups, the median values of steroid DAS28, CDAI, ERS, PCR, tender joints, swollen joints, VAS, HAQ, PGA patients, and PGA physicians were reduced with a statistically significant difference comparing these values with the baseline values. The difference in age did not impact the effectiveness of the drug. The lipid profile data also did not demonstrate significant differences between the two age groups; however, the comparison between younger vs. older patients' populations regarding the total cholesterol/HDL ratio and LDL/HDL ratio shows a statistically significant difference: total cholesterol/HDL 3.4 (2.12-3.66) vs. 3.64 (3.36-4.13) p = 0.0004, LDL/HDL 1.9 (0.98-2.25) vs. 2.41 (2.04-2.73) p = 0.0002. There are no differences regarding the atherogenic index (LDL-C/HDL-C) and coronary risk index (TC/HDL-C) compared to baseline.

CONCLUSIONS

After six months of treatment with FIL, the older population group showed a higher level of LDL and a lower level of HDL compared to younger patients. The atherogenic index and coronary risk index are higher in patients aged ≥ 65 years, but interestingly, there were no differences when comparing the 6-month data to baseline values. This condition highlights the impact of typical risk factors that act independently of treatment with Filgotinib.

Potential applications of JAK inhibitors, clinically approved drugs against autoimmune diseases, in cancer therapy

Disturbances in immunoregulation may lead to both cancer and autoimmune diseases. Many therapeutic drugs for autoimmune diseases also display anti-tumor efficacy. The Janus kinase/signal transducer and activator of transcription signaling pathways are involved in the secretion of more than 50 distinct cytokines, which have critical roles in inducing autoimmune diseases and tumorigenesis. Thus, Janus kinases have become classical immunotherapeutic targets for immune disease. More than 70 Janus kinase inhibitors have been approved as immunomodulatory drugs for clinical use, of which 12 are used in the treatment of autoimmune diseases. This systematic review aims to elucidate the anti-tumor role of clinically approved Janus kinase inhibitors that were primarily designed for the treatment of autoimmune diseases and their potential for clinical translation as cancer treatments.

Synthesis and clinical application of small-molecule inhibitors of Janus kinase

Janus kinase (JAK) plays a crucial role in intracellular signaling pathways, particularly in cytokine-mediated signal transduction, making them attractive therapeutic targets for a wide range of diseases, including autoimmune disorders, myeloproliferative neoplasms, and inflammatory conditions. The review provides a comprehensive overview of the development and therapeutic potential of small-molecule inhibitors targeting JAK family of proteins in various clinical trials. It also discusses the mechanisms of action, specificity, and selectivity of these inhibitors, shedding light on the challenges associated with achieving target selectivity while minimizing off-target effects. Moreover, the review offers insights into the clinical applications of JAK inhibitors, summarizing the ongoing clinical trials and the Food and Drug Administration (FDA)-approved JAK inhibitors currently available for various diseases. Overall, this review provides a thorough examination of the synthesis and clinical use of typical small-molecule JAK inhibitors in different clinical stages and offers a bright future for the development of novel small-molecule JAK inhibitors.

JAK Inhibitors in Solid Organ Transplantation

Janus kinase (JAK) inhibitors are a novel group of immunosuppressive drugs approved to treat certain rheumatic and allergic disorders; however, their efficacy in the regulation of alloimmune responses after solid organ transplantation has not yet been elucidated. In the present review, we have summarized the results of in vitro, in vivo, experimental, and clinical trial studies about the efficacy and safety of JAK inhibitors in improving allograft survival in solid organ transplantations, including kidney, heart, lung, and liver transplants. Moreover, reports on administering JAK inhibitors to steroid-resistant patients with graft versus host disease (GvHD) after solid organ transplantation have been reviewed. Overall findings are suggestive of a beneficial role for JAK inhibitors in organ transplantation: for example, they have been shown to improve allograft function, reduce the rate and score of acute rejection, downregulate the expression of proinflammatory cytokines and adhesion molecules, and decrease oxidative stress. However, the adverse effects of these drugs, in particular bone marrow suppression and infection, remain an obstacle.

Long-Term Safety, Efficacy, and Patient-Centered Outcomes of Filgotinib in the Treatment of Rheumatoid Arthritis: Current Perspectives

Filgotinib is an orally administered, preferential Janus kinase (JAK) inhibitor indicated for the treatment of moderate-to-severe rheumatoid arthritis (RA). The short-term safety, efficacy, and patient-reported outcomes (PROs) with filgotinib from Phase 2b/3 clinical trials (DARWIN 1 and 2; FINCH 1, 2, and 3) are described in patients who inadequately responded to methotrexate (MTX) and biologic disease-modifying antirheumatic drugs or who were naïve to MTX. This article reviews the safety and efficacy from the long-term extension (LTE) trials, DARWIN 3 (N=739) and FINCH 4 (N=2731), and PROs across the filgotinib development program in RA. Overall, in the DARWIN clinical trials (conducted from 2013-2023), patients received their LTE treatment for ≤8 years, while in the FINCH trials (ongoing from 2016-2025), patients received filgotinib treatment for ≤6 years in the LTE. The longer-term safety profile and consistent, sustained efficacy (American College of Rheumatology 20/50/70, Clinical Disease Activity Index, and Disease Activity Scale in 28 joints with C-reactive protein response rates) of filgotinib were largely similar to those observed in the shorter-term parent trials ≤52 weeks. PRO results from the parent trials showed improvements in patients' quality of life with filgotinib treatment, which compared to or exceeded improvements seen with placebo and active comparators (adalimumab, MTX). Filgotinib has a higher specificity for JAK1 compared with other therapeutic treatments, leading to reduced inhibition of JAK2/3-dependent pathways, potentially providing a distinct safety profile. Filgotinib is approved in Europe and Japan for treatment of people with moderate-to-severe RA, though it has not been approved by the US Food and Drug Administration, due to concerns around the benefit/risk profile of the filgotinib 200-mg dosage and the potential impact on semen parameters.

The impact of EMA recommendations on the real-life use of Janus kinases inhibitors for rheumatoid arthritis: the Expanded Risk Score in RA as a tool to quantify the risk of cardiovascular events

Objective

To evaluate in patients with rheumatoid arthritis (RA) the impact of EMA recommendations on the real-life prescription of JAK inhibitors (JAKis) and the use of the Expanded Risk Score in RA (ERS-RA) to quantify the risk of major adverse cardiac events (MACE).

Methods

We conducted a retrospective analysis of real-life RA patients treated with JAKis. Patients were classified as ineligible for JAKis if they fulfilled EMA criteria (>65 years-old, history of malignancy, or increased risk of venous thromboembolic events [VTE] or MACE including smoking). Risk of MACE was defined according to ORAL Surveillance trial inclusion criteria (ORALSURV) or by using the ERS-RA.

Results

Of 194 patients enrolled, 57.9% were classified as ineligible according to EMA definition (ORALSURV criteria). The most frequent reason for ineligibility was increased MACE risk (70.2%), followed by age>65 (34.2%), smoking (30.7%), and increased risk of VTE (20.2%) or malignancy (7%). The use of the ERS-RA reduced the rate of patients carrying an increased CV risk to 18.6% (p<0.001 versus ORALSURV), leading to 46.4% overall ineligible patients. Over a drug-exposure of 337 patient/years, we observed 2 VTE, one MACE (non-fatal stroke), and one solid malignancy (all in the group of patients classified as ineligible according to both the definitions).

Conclusions

Rigorous application of EMA indications in clinical practice could result in the exclusion of a large proportion of RA patients from treatment with JAKis. A proper quantification of the risk for MACE by dedicated tools as ERS-RA is advocated to better tailor the management of RA.

ReLiFiRa (Real Life Filgotinib in Rheumatoid Arthritis): Retrospective Study of Efficacy and Safety in Common Clinical Practice

BACKGROUND

Filgotinib (FIL) is a selective JAK1 inhibitor with an affinity 30-fold higher than JAK2, approved to treat moderate to severe active rheumatoid arthritis (RA), in adults with inadequate response or intolerance to one or more disease-modifying antirheumatic drugs (DMARDs).

METHODS

We conducted a retrospective, multicentric study in order to evaluate efficacy and safety of FIL 200 mg daily therapy, after 3 and 6 months, in 120 patients affected by RA, managed in Tuscany and Umbria rheumatological centers. The following clinical records were analyzed: demographical data, smoking status, previous presence of comorbidities (Herpes zoster -HZ- infection, venous thromboembolism -VTE-, major adverse cardiovascular events -MACE-, cancer, diabetes, and hypertension), disease duration, presence of anti-citrullinated protein antibodies (ACPA), rheumatoid factor (RF), number of biological failures, and prior csDMARDs utilized. At baseline, and after 3 (T3) and 6 (T6) months of FIL therapy, we evaluated mean steroid dosage, csDMARDs intake, clinimetric indexes (DAS28, CDAI, HAQ, patient and doctor PGA, VAS), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and body mass index (BMI).

RESULTS

At baseline, the mean disease duration was 9.4 ± 7.5 years; the prevalence of previous HZ infection, VTE, MACE, and cancer was respectively 4.12%, 0%, 7.21%, and 0.83%, respectively. In total, 76.3% of patients failed one or more biologics (one biological failure, 20.6%; two biological failures, 27.8%; three biological failures, 16.5%; four biological failures, 10.3%; five biological failures, 1.1%). After 3 months of FIL therapy, all clinimetric index results significantly improved from baseline, as well as after 6 months. Also, ESR and CRP significatively decreased at T3 and T6. Two cases of HZ were recorded, while no new MACE, VTE, or cancer were recorded during the observation time.

CONCLUSION

Despite the limitations of the retrospective study and of the observational period of only 6 months, real-life data on the treatment of RA patients with FIL demonstrate that this Jak inhibitor therapy is safe in terms of CV, VTE events, and occurrence of cancer, and is also effective in a population identified as "difficult to treat" due to failure of previous b-DMARD therapy.

Efficacy of Filgotinib in Patients with Ulcerative Colitis by Line of Therapy in the Phase 2b/3 SELECTION Trial

BACKGROUND AND AIMS

The efficacy of new therapies for ulcerative colitis [UC] is usually influenced by previous biologic use. These post hoc analyses of SELECTION, a placebo-controlled phase 2b/3 trial in patients with moderately to severely active UC, evaluated the efficacy of filgotinib, an oral Janus 1 kinase preferential inhibitor, with respect to prior biologic failure.

METHODS

The effect of filgotinib 200 mg (FIL200) relative to placebo was compared in biologic-naïve and biologic-failed patient groups, and in further subgroups by number of failed biologics [1 or >1], biologic mechanism of action [MoA] classes [1 or 2] and tumour necrosis factor [TNF] antagonists [1 or >1]. Odds ratios [ORs] for clinical remission at week 10 [induction] and hazard ratios [HRs] for protocol-specific disease worsening [PSDW] from week 11 to week 58 [maintenance] were calculated.

RESULTS

At week 10, FIL200-treated patients were more likely to achieve clinical remission than placebo-treated patients in the biologic-naïve (OR [95% confidence interval, CI]: 1.98 [1.14-3.44]) and biologic-failed (3.91 [1.33-11.48]) groups. During maintenance, FIL200-treated patients had a reduced risk of PSDW in the biologic-naïve (HR [95% CI]: 0.22 [0.11-0.44]) and biologic-failed (0.22 [0.12-0.40]) groups, and in all biologic-failed subgroups (except >1 TNF antagonist failure). The data suggest that the likelihood of PSDW at week 58 increased with increasing numbers of failed biologics.

CONCLUSIONS

FIL200 induced and maintained benefits relative to placebo regardless of previous biologic use; however, the estimated therapeutic benefit was greatest in biologic-naïve patients and patients previously treated with one biologic or biologic MoA class. [ClinicalTrials.gov: NCT02914522].

Chemistry and Pharmacology of Fluorinated Drugs Approved by the FDA (2016-2022)

Fluorine is characterized by high electronegativity and small atomic size, which provide this molecule with the unique property of augmenting the potency, selectivity, metabolic stability, and pharmacokinetics of drugs. Fluorine (F) substitution has been extensively explored in drug research as a means of improving biological activity and enhancing chemical or metabolic stability. Selective F substitution onto a therapeutic or diagnostic drug candidate can enhance several pharmacokinetic and physicochemical properties such as metabolic stability and membrane permeation. The increased binding ability of fluorinated drug target proteins has also been reported in some cases. An emerging line of research on F substitution has been addressed by using 18F as a radiolabel tracer atom in the extremely sensitive methodology of positron emission tomography (PET) imaging. This review aims to report on the fluorinated drugs approved by the US Food and Drug Administration (FDA) from 2016 to 2022. It cites selected examples from a variety of therapeutic and diagnostic drugs. FDA-approved drugs in this period have a variety of heterocyclic cores, including pyrrole, pyrazole, imidazole, triazole, pyridine, pyridone, pyridazine, pyrazine, pyrimidine, triazine, purine, indole, benzimidazole, isoquinoline, and quinoline appended with either F-18 or F-19. Some fluorinated oligonucleotides were also authorized by the FDA between 2019 and 2022.

Leveraging Genomic and Bioinformatic Analysis to Enhance Drug Repositioning for Dermatomyositis

Dermatomyositis (DM) is an autoimmune disease that is classified as a type of idiopathic inflammatory myopathy, which affects human skin and muscles. The most common clinical symptoms of DM are muscle weakness, rash, and scaly skin. There is currently no cure for DM. Genetic factors are known to play a pivotal role in DM progression, but few have utilized this information geared toward drug discovery for the disease. Here, we exploited genomic variation associated with DM and integrated this with genomic and bioinformatic analyses to discover new drug candidates. We first integrated genome-wide association study (GWAS) and phenome-wide association study (PheWAS) catalogs to identify disease-associated genomic variants. Biological risk genes for DM were prioritized using strict functional annotations, further identifying candidate drug targets based on druggable genes from databases. Overall, we analyzed 1239 variants associated with DM and obtained 43 drugs that overlapped with 13 target genes (JAK2, FCGR3B, CD4, CD3D, LCK, CD2, CD3E, FCGR3A, CD3G, IFNAR1, CD247, JAK1, IFNAR2). Six drugs clinically investigated for DM, as well as eight drugs under pre-clinical investigation, are candidate drugs that could be repositioned for DM. Further studies are necessary to validate potential biomarkers for novel DM therapeutics from our findings.

Molecular Basic of Pharmacotherapy of Cytokine Imbalance as a Component of Intervertebral Disc Degeneration Treatment

Intervertebral disc degeneration (IDD) and associated conditions are an important problem in modern medicine. The onset of IDD may be in childhood and adolescence in patients with a genetic predisposition. With age, IDD progresses, leading to spondylosis, spondylarthrosis, herniated disc, spinal canal stenosis. One of the leading mechanisms in the development of IDD and chronic back pain is an imbalance between pro-inflammatory and anti-inflammatory cytokines. However, classical therapeutic strategies for correcting cytokine imbalance in IDD do not give the expected response in more than half of the cases. The purpose of this review is to update knowledge about new and promising therapeutic strategies based on the correction of the molecular mechanisms of cytokine imbalance in patients with IDD. This review demonstrates that knowledge of the molecular mechanisms of the imbalance between pro-inflammatory and anti-inflammatory cytokines may be a new key to finding more effective drugs for the treatment of IDD in the setting of acute and chronic inflammation.

JAK inhibitors differentially modulate B cell activation, maturation and function: A comparative analysis of five JAK inhibitors in an in-vitro B cell differentiation model and in patients with rheumatoid arthritis

Background

Janus kinase (JAK) inhibitors have been approved for the treatment of several immune-mediated diseases (IMIDs) including rheumatoid arthritis (RA) and psoriatic arthritis and are in clinical trials for numerous other IMIDs. However, detailed studies investigating the effects of different JAK inhibitors on B cells are missing. Within this study, we therefore aimed to characterize the effect of JAK inhibition on the B cell compartment.

Methods

To this end, we investigated the B cell compartment under JAK inhibition and compared the specific effects of the different JAK inhibitors tofacitinib (pan-JAK), baricitinib (JAK1/2), ruxolitinib (JAK1/2), upadacitinib (JAK1/2) as well as filgotinib (selective JAK1) on in-vitro B cell activation, proliferation, and class switch recombination and involved pathways.

Results

While B cell phenotyping of RA patients showed an increase in marginal zone (MZ) B cells under JAK inhibition, comparison with healthy donors revealed that the relative frequency of MZ B cells was still lower compared to healthy controls. In an in-vitro model of T-cell-independent B cell activation we observed that JAK1/2 and selective JAK1 inhibitor treatment led to a dose-dependent decrease of total B cell numbers. We detected an altered B cell differentiation with a significant increase in MZ-like B cells and an increase in plasmablast differentiation in the first days of culture, most pronounced with the pan-JAK inhibitor tofacitinib, although there was no increase in immunoglobulin secretion in-vitro. Notably, we further observed a profound reduction of switched memory B cell formation, especially with JAK1/2 inhibition. JAK inhibitor treatment led to a dose-dependent reduction of STAT3 expression and phosphorylation as well as STAT3 target gene expression and modulated the secretion of pro- and anti-inflammatory cytokines by B cells.

Conclusion

JAK inhibition has a major effect on B cell activation and differentiation, with differential outcomes between JAK inhibitors hinting towards distinct and unique effects on B cell homeostasis.

JAK inhibition in the treatment of inflammatory rheumatic diseases

The most common immune-mediated inflammatory rheumatic diseases, rheumatoid arthritis, psoriatic arthritis and axial spondyloarthritis and have reached significant advances in recent years with the introduction of biological therapies against cytokines and immune cells, but also against intracellular enzymes, specifically Janus kinases (JAKs). Intracellular JAK signalling is activated by binding of various cytokines or growth factors to the respective cellular receptors, allowing the activation of STAT (Signal Transducers and Activators of Transcription) transcription factors and ultimately the transcription of genes with important roles during the innate and adaptive immune response. Four Janus kinases have been described: JAK1, JAK2, JAK3 and tyrosine kinase-2 (TYK2). Four JAK inhibitors (tofacitinib, baricitinib, upadacitinib and filgotinib) are currently approved for the treatment of rheumatoid arthritis, and some for the treatment of psoriatic arthritis and axial spondyloarthritis. JAK inhibitors have varying selectivity against individual kinases. Some JAK inhibitors are being tested in other rarer systemic connective tissue diseases. The general advantages of JAK inhibitors are oral administration, rapid onset of action, and efficacy in monotherapy. The safety profile of JAK inhibitors compared with biologic therapy appears to be comparable, with a higher incidence of herpes zoster, and an increased incidence of major cardiovascular disease, thromboembolic complications, and cancer in at-risk patients is discussed. The aim of this paper will be to summarize the latest findings on JAK inhibitors in approved indications for the most common rheumatic diseases.

Filgotinib for moderately to severely active ulcerative colitis

INTRODUCTION

Filgotinib is an oral Janus kinase type 1 (JAK1) selective inhibitor with demonstrated efficacy and safety in ulcerative colitis (UC). The aim of this review is to summarize the available evidence on pharmacological characteristics, efficacy, and safety of filgotinib in UC.

AREAS COVERED

Pubmed, Scopus, and Embase databases were searched for all relevant studies reporting the efficacy and safety of filgotinib in patients with moderate to severe UC. We particularly focused on the risk of zoster infection and venous thromboembolism compared to other JAK inhibitors.

EXPERT OPINION

Filgotinib has remarkable efficacy, safety, and tolerability profiles in the treatment of moderate-to-severe active UC. It can be used in both biologic-naïve and biologic-experienced patients. The rapid mechanism of action and its oral administration route make it a reliable therapeutic option.

Lessons learned from the preclinical discovery and development of sarilumab for the treatment of rheumatoid arthritis

INTRODUCTION

Rheumatoid arthritis (RA) pathogenesis is driven by a complex network of proinflammatory cytokines, among which interleukin-6 (IL-6) plays a key role in inducing and perpetuating chronic inflammation. Targeting the IL-6 pathway has shown to be an invaluable treatment strategy, as demonstrated by the results accrued in the last decade with the first IL-6 inhibitor, tocilizumab. More recently, a second monoclonal antibody blocking IL-6, sarilumab, has enriched our armamentarium by proving outstanding efficacy in RA treatment.

AREAS COVERED

After exploring the IL-6 pathway under physiological conditions and in the RA pathogenesis, in this review we discuss the pharmacologic properties of sarilumab and the clinical trials that constitute the sarilumab development program and have enabled its licensed application.

EXPERT OPINION

Results from clinical trials confirmed the efficacy and safety of sarilumab for the treatment of RA, similar to its precursor tocilizumab. Blocking IL-6 pathway results in comprehensive control of the disease, from both physician's and patient's perspective, and of RA comorbidities and extra-articular manifestations which are largely IL-6 driven. Finally, the proven efficacy of sarilumab as monotherapy arises the drug as a required therapeutic alternative considering the large proportion of patients intolerant or inadequate to receive conventional synthetic disease-modifying drugs (csDMARDs).

Advances in Immunosuppressive Agents Based on Signal Pathway

Immune abnormality involves in various diseases, such as infection, allergic diseases, autoimmune diseases, as well as transplantation. Several signal pathways have been demonstrated to play a central role in the immune response, including JAK/STAT, NF-κB, PI3K/AKT-mTOR, MAPK, and Keap1/Nrf2/ARE pathway, in which multiple targets have been used to develop immunosuppressive agents. In recent years, varieties of immunosuppressive agents have been approved for clinical use, such as the JAK inhibitor tofacitinib and the mTOR inhibitor everolimus, which have shown good therapeutic effects. Additionally, many immunosuppressive agents are still in clinical trials or preclinical studies. In this review, we classified the immunosuppressive agents according to the immunopharmacological mechanisms, and summarized the phase of immunosuppressive agents.

A Natural Plant Ingredient, Menthone, Regulates T Cell Subtypes and Lowers Pro-inflammatory Cytokines of Rheumatoid Arthritis

Rheumatoid arthritis (RA) is an autoimmune disease with nearly 1.6 billion patients worldwide and an incidence of 0.5-1%. In recent years, basic and clinical studies have revealed that immune cell responses and corresponding secretion of inflammatory factors are important in the control of RA development. Our study found that a natural plant ingredient, menthone, could be used as a potential antirheumatism compound. In vivo observations demonstrated that menthone alleviates collagen II-induced arthritis (CIA) in mice. Furthermore, we found that menthone regulates the number of Th1 and Th17 cells in CIA mice. Importantly, menthone significantly inhibits the release of pro-inflammatory cytokines, including TNF-α, IL-1β, and IL-6, in CIA mice. Our study suggests a potential component for the development of drugs to treat rheumatoid arthritis.

An updated overview of recent advances, challenges, and clinical considerations of IL-6 signaling blockade in severe coronavirus disease 2019 (COVID-19)

Since 2019, COVID-19 has become the most important health dilemma around the world. The dysregulated immune response which results in ARDS and cytokine storm has an outstanding role in the progression of pulmonary damage in COVID-19. IL-6, through induction of pro-inflammatory chemokines and cytokines, is the pioneer of the hyperinflammatory condition and cytokine storm in severe COVID-19. Therefore, IL-6 pathway blockade is considered an emerging approach with high efficacy to reduce lung damage in COVID-19. This article aims to review the pleiotropic roles of the IL-6 pathway in lung damage and ARDS in severe COVID-19, and the rationale for IL-6 signaling blockade at different levels, including IL-6 soluble and membrane receptor pathways, IL-6 downstream signaling (such as JAK-STAT) inhibition, and non-specific anti-inflammatory therapeutic approaches. Recent clinical data of each method, with specific concentration on tocilizumab, along with other new drugs, such as sarilumab and siltuximab, have been discussed. Challenges of IL-6 signaling inhibition, such as the risk of superinfection and hepatic injury, and possible solutions have also been explained. Moreover, to achieve the highest efficacy, ongoing clinical trials and special clinical considerations of using different IL-6 inhibitors have been discussed in detail. Special considerations, including the appropriate timing and dosage, monotherapy or combination therapy, and proper side effect managment must be noticed regarding the clinical administration of these drugs. Future studies are still necessary to improve the productivity and unknown aspects of IL-6 signaling blockade for personalized treatment of severe COVID-19.

JAK inhibitors in crohn's disease: ready to go?

INTRODUCTION

Crohn's disease (CD) is a chronic, relapsing inflammatory bowel disease that can lead to significant organ damage and impaired quality of life. To date, a considerable proportion of patients does not respond to biologic compounds. It is, therefore, necessary to find alternative options with adequate efficacy and safety profiles in order to increase the chances of obtaining an enduring remission of disease. Janus kinase (JAK) inhibitors are a new class of compounds that might well serve this purpose. The aim of our review is to report the available data from clinical trials testing these new drugs in patients suffering from CD.

AREAS COVERED

PubMed database and ClinicalTrials.gov website were consulted in order to find the clinical trials evaluating the efficacy and safety profiles of JAK-inhibitors in CD patients, including the following compounds: tofacitinib, filgotinib, upadacitinib, TD-1473, and Pf-06651600/Pf-06700841.

EXPERT OPINION

JAK-inhibitors are a promising class of oral compounds in moderate-severe CD. Further clinical trials are necessary in order to implement the available knowledge, especially on their long-term safety issues.

Benefit-Risk Analysis of Upadacitinib Compared with Adalimumab in the Treatment of Patients with Moderate-to-Severe Rheumatoid Arthritis

INTRODUCTION

Rheumatoid arthritis (RA) is a chronic autoimmune disease requiring long-term treatment. Upadacitinib (UPA), a Janus kinase (JAK) inhibitor, is a new treatment for RA. The benefit-risk profile of a medication is best understood by evaluating the number needed to treat (NNT) and the number needed to harm (NNH). This analysis evaluated the comparative risk-benefit of UPA versus adalimumab (ADA).

METHODS

Post-hoc analyses were performed using data from the SELECT-COMPARE trial of UPA versus placebo (PBO) and UPA versus ADA among patients with active RA who remained on stable methotrexate (MTX) treatment and had an inadequate response; patients who failed to achieve response were rescued by predefined criteria-PBO or ADA switch to UPA, and UPA switch to ADA (all patients on PBO were switched to UPA at week 26). This analysis assessed efficacy and adverse events of special interest (AESIs) at week 26, 48, and 156 (3 years). NNT and NNH (95% confidence intervals) values were calculated between UPA versus ADA for all time points, and between UPA versus PBO for week 26. NNT and NNH values were applied to a hypothetical cohort of 100 patients to estimate the comparative efficacy and safety profiles.

RESULTS

UPA consistently showed greater efficacy than ADA, as evidenced by NNT values < 10 for achievement of Disease Activity Score in 28 joints based on C-reactive protein (DAS28-CRP) of < 2.6 and ≤ 3.2, respectively, and functional improvement. Based on indices for disease assessment other than the DAS28-CRP, remission outcomes were higher with UPA versus ADA over 26 weeks (NNTs: 7-12), 48 weeks (NNTs: 9-16), and 156 weeks (NNTs: 9-15). With the exception of herpes zoster, other AESIs demonstrated a similar risk with UPA versus ADA.

CONCLUSION

In patients with active RA despite MTX use, UPA demonstrated an incremental achievement of clinical outcomes compared to ADA together with a similar profile of AESIs with ADA (with the exception of herpes zoster).

Toward Overcoming Treatment Failure in Rheumatoid Arthritis

Rheumatoid arthritis (RA) is an autoimmune disorder characterized by inflammation and bone erosion. The exact mechanism of RA is still unknown, but various immune cytokines, signaling pathways and effector cells are involved. Disease-modifying antirheumatic drugs (DMARDs) are commonly used in RA treatment and classified into different categories. Nevertheless, RA treatment is based on a "trial-and-error" approach, and a substantial proportion of patients show failed therapy for each DMARD. Over the past decades, great efforts have been made to overcome treatment failure, including identification of biomarkers, exploration of the reasons for loss of efficacy, development of sequential or combinational DMARDs strategies and approval of new DMARDs. Here, we summarize these efforts, which would provide valuable insights for accurate RA clinical medication. While gratifying, researchers realize that these efforts are still far from enough to recommend specific DMARDs for individual patients. Precision medicine is an emerging medical model that proposes a highly individualized and tailored approach for disease management. In this review, we also discuss the potential of precision medicine for overcoming RA treatment failure, with the introduction of various cutting-edge technologies and big data.

Quantification of the janus kinase 1 inhibitor upadacitinib in human plasma by LC-MS/MS

Upadacitinib is a selective janus-kinase-1 inhibitor effective in the treatment of autoimmune related diseases like rheumatoid arthritis or psoriatic arthritis. Here, we described a LC-MS/MS method for the quantification of upadacitinib in human plasma applicable for therapeutic drug monitoring. Pexidartinib was used as internal standard. Plasma samples were prepared by acidic protein precipitation and the analytes were separated on a C-18 reversed phase column. Detection took place by tandem mass spectroscopy after ionization in the positive mode and collision induced fragmentation at m/z 381 → 256, 213 for upadacitinib and m/z 418 → 258, 165 for pexidartinib. The calibration function was linear in the range of 0.15 - 150 ng/mL. Precisions and accuracies were better than 10% in intra- as well as inter-day evaluations. The method was applied in therapeutic drug monitoring of patients undergoing treatment for rheumatoid arthritis with the standard dose of 15 mg upadacitinib extended release formulation once daily. At steady state, we found trough levels of 4.13 (3.51 - 11.0) ng/mL, which is comparable to values found in healthy volunteers receiving the same dose (2.8 ± 1.2 ng/mL).

Immunological Targets of Biologic Drugs in Allergic Skin Diseases in Children

Atopic dermatitis and urticaria are two invalidating skin disorders that are very common in children. Recent advances in the understanding of their specific intracellular molecular pathways have permitted the development of precise biological molecules, targeting inflammatory mediators and arresting the pathogenetic pathways of skin diseases. Many biologics with promising results have been studied, although few are currently approved in children. In this review, we aim to provide the latest evidence about the use, indications, efficacy and safety of biologic therapies to treat atopic dermatitis and chronic urticaria in children and adolescents.

Safety of Janus kinase (JAK) inhibitors in the short-term treatment of atopic dermatitis

Atopic dermatitis (AD) is a chronic heterogeneous condition characterized by erythematous, pruritic, and inflamed skin. Janus kinase (JAK) inhibitors are a new class of drugs that target proteins in the Janus kinase-signal transducer and activator of transcription (JAK-STAT) pathway. These drugs can be administered orally or topically to inhibit signaling of the JAK-STAT pathway and minimize the production of proinflammatory cytokines. The efficacy and safety of JAK inhibitors have been investigated in phase 2 and 3 clinical trials for AD. The safety of new medications, which are immunosuppressive by nature, is of utmost concern for the prescriber and patient alike. Herein we summarize the safety results of clinical trials using oral abrocitinib, upadacitinib, and baricitinib, as well as topical ruxolitinib and delgocitinib for the treatment of AD. The most prevalent (2-5% occurrence rate) treatment-emergent adverse events from oral JAK inhibitor use in AD were nausea, upper respiratory tract infection, headache, herpes zoster, herpes simplex, acne, increased blood creatine phosphokinase levels, and decreased platelet counts. Topical JAK inhibitors were not associated with systemic effects. All studies reported that JAK inhibitors were well tolerated in patients with AD in comparison with the control group. While the use of JAK inhibitors in patients suffering from AD is very promising, trials reported to date are of short duration (maximum 16 weeks), and more information on the long-term safety of these novel agents is required.

TYK2 in Cancer Metastases: Genomic and Proteomic Discovery

Advances in genomic analysis and proteomic tools have rapidly expanded identification of biomarkers and molecular targets important to cancer development and metastasis. On an individual basis, personalized medicine approaches allow better characterization of tumors and patient prognosis, leading to more targeted treatments by detection of specific gene mutations, overexpression, or activity. Genomic and proteomic screens by our lab and others have revealed tyrosine kinase 2 (TYK2) as an oncogene promoting progression and metastases of many types of carcinomas, sarcomas, and hematologic cancers. TYK2 is a Janus kinase (JAK) that acts as an intermediary between cytokine receptors and STAT transcription factors. TYK2 signals to stimulate proliferation and metastasis while inhibiting apoptosis of cancer cells. This review focuses on the growing evidence from genomic and proteomic screens, as well as molecular studies that link TYK2 to cancer prevalence, prognosis, and metastasis. In addition, pharmacological inhibition of TYK2 is currently used clinically for autoimmune diseases, and now provides promising treatment modalities as effective therapeutic agents against multiple types of cancer.

JAK inhibitors, psoriatic arthritis, and axial spondyloarthritis: a critical review of clinical trials

INTRODUCTION

Psoriatic arthritis (PsA) and spondyloarthritis (SpA) are inflammatory arthritides associated with progressive damage, deformity and morbidity. Janus kinase (JAK) inhibitors block JAKs, cytoplasmic protein tyrosine kinases important in signal transduction and immune processes that are currently being studied as synthetic disease modifying anti-rheumatic drugs (tsDMARDs) in psoriatic arthritis and spondyloarthritis.

AREAS COVERED

This review evaluates published phase 2 and 3 clinical trial data for JAK kinase inhibitors for psoriatic arthritis and spondyloarthritis. A literature search using PubMed was conducted using the following keywords: 'psoriatic arthritis', 'ankylosing spondylitis', 'axial spondyloarthritis', 'non-radiographic axial spondyloarthritis', 'tofacitinib', 'baricitinib', 'filgotinib' and 'upadacitinib'. Mechanism of action, phase 2 and 3 clinical trial data, including efficacy and safety, are discussed.

EXPERT OPINION

JAK inhibitors are important orally administered agents conferring different degrees of selectivity toward JAK1, JAK2, and JAK3 which may have implications on efficacy and safety in PsA and SpA. Phase 2 and 3 clinical trials in PsA for tofacitinib and upadacitinib and phase 2 for filgotinib confirmed efficacy comparable to biologic DMARDs. In SpA, phase 2 and 2/3 studies confirmed significant efficacy of tofacitinib, filgotinib and upadacitinib compared to placebo. Safety was comparable to clinical trial, long-term extension, and registry data for rheumatoid arthritis.

Clinical use of Jak 1 inhibitors for rheumatoid arthritis

The uptake of Jak inhibitors in the RA space has been among the most rapid in rheumatology, based on the results of comprehensive clinical trial programmes of five agents. Newer generations of Jak inhibitors, like upadacitinib and filgotinib, target Jak 1 selectively with the aim of maximizing efficacy and to improve safety. This article will review the clinical significance of evidence on: (i) Jak 1 selectivity; (ii) efficacy from the SELECT and FINCH clinical trial programmes including patient intolerant or inadequately responding to MTX (MTX-IR) and other csDMARDs patients who are bDMARD-IR) and those using monotherapy when MTX is not tolerated or contraindicated and those treated when methotrexate naive; and (iii) safety from the clinical trial programmes of these two agents will be discussed.

JAK1: Number one in the family; number one in inflammation?

Several cytokines involved in inflammatory pathologies signal via the Janus kinase-signal transducer and activator of transcription pathway. Four JAKs are known: JAK1, JAK2, JAK3 and TYK2. The specific activation of JAKs and STATs determines the biological effects of each cytokine. JAK1 is involved in the signalling of 'γc' receptor cytokines (IL-2, IL-4, IL-7, IL-9, IL-15 and IL-21), pro-inflammatory cytokines including IL-6, as well as IFN. The critical position of JAK1 downstream of these cytokines suggests that JAK1-selective inhibitors are comparable to non-selective ones, without the unwanted consequences of JAK2- or JAK3-blockade. JAK inhibition has led to a better understanding of the biology of synovial inflammation and bone homeostasis. Moreover, the efficacy of non-selective JAK inhibitors and novel JAK1-selective drugs in RA supports a role for JAK1 in its pathogenesis. JAK1-selective drugs are also showing promise in axial spondyloarthritis, suggesting that they may target additional regulatory pathways that impact cytokines such as TNF and IL-17A, which do not use JAKs. Additionally, evidence now supports a JAK1 predominance in the signalling of IL-6 and oncostatin M, and indirectly, of TNF in synovial fibroblasts, macrophages and endothelial cells. Notably, bone homeostasis is also dependent on cytokines relying on JAK1 signalling to promote receptor activator of NF-κB ligand expression in osteoblasts and T cells, contributing to osteoclastogenesis. Here, the contribution of JAK1 over other kinases is unclear. While beneficial effects of JAK inhibitors on bone erosion are supported by preclinical and clinical data, effects on new bone formation in axial spondyloarthritis requires additional study.

Phase III trials of JAK1 selective inhibitors in rheumatoid arthritis

Upadacitinib and filgotinib, two JAK1 selective drugs have undergone extensive phase III clinical trials in RA and have demonstrated rapid improvements in disease activity, function and patient reported outcomes. Six global phase III randomized controlled clinical trials (SELECT phase III program) evaluated the efficacy and safety of upadacitinib and four clinical phase III trials (the FINCH program) evaluated the efficacy and safety of filgotinib. This article is a critical review of all these studies with focus on the therapeutic efficacy in RA. The aim is to display the data that could allow the approval of these new drugs for the treatment of RA (upadacitinib has been already approved in most of the markets around the world).

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/STAT Activation: A General Mechanism for Bone Development, Homeostasis, and Regeneration

The Janus kinase (JAK) signal transducer and activator of transcription (STAT) signaling pathway serves as an important downstream mediator for a variety of cytokines, hormones, and growth factors. Emerging evidence suggests JAK/STAT signaling pathway plays an important role in bone development, metabolism, and healing. In this light, pro-inflammatory cytokines are now clearly implicated in these processes as they can perturb normal bone remodeling through their action on osteoclasts and osteoblasts at both intra- and extra-articular skeletal sites. Here, we summarize the role of JAK/STAT pathway on development, homeostasis, and regeneration based on skeletal phenotype of individual JAK and STAT gene knockout models and selective inhibition of components of the JAK/STAT signaling including influences of JAK inhibition in osteoclasts, osteoblasts, and osteocytes.

New emergent therapies for atopic dermatitis: A review of safety profile with respect to female fertility, pregnancy, and breastfeeding

Atopic dermatitis (AD) is a chronic relapsing inflammatory skin disease. Systemic treatment is usually mandatory in moderate-to-severe AD of the adult; these patients need to be informed about safe and effective management of AD also regarding the reproduction. Treating a pregnant woman with AD with systemic drugs may affect the unborn child. While effects of traditional systemic treatments for AD on female fertility, pregnancy, and breastfeeding are largely known, data about new emergent therapies for AD are still poor. Treating pregnant or lactating women with AD can be a challenge since no large clinical studies on its possible effects and side-effects on conception, pregnancy, the unborn child and lactation are currently available for new AD treatments.

Performance of Janus kinase inhibitors in psoriatic arthritis with axial involvement in indirect comparison with ankylosing spondylitis: a retrospective analysis from pooled data

BACKGROUND AND OBJECTIVE

As the well-acknowledged autoimmune disease, Janus kinase (JAK) is thought to play important roles in the progression of tissue injury in spondyloarthropathy. From a current perspective, JAK inhibitors could be applied to both psoriatic arthritis (PsA) and ankylosing spondylitis (AS). Nonetheless, it is reasonable to doubt whether PsA and AS differentially respond to JAK inhibitors.

METHODS

Different databases were searched for full-text publication based on inclusion and exclusion criteria. For data-pooling, a fixed-effect model was applied if heterogeneity was not detected. All results of the analysis were illustrated as forest plots. Publication bias was assessed using Begg's adjusted rank correlation test. The standard mean difference (SMD) was calculated in continuous variables. The pooled odds ratio was calculated in categorical variables.

RESULTS

Nine clinical studies were finally included with a 3-month follow-up. The efficacy and safety of JAK inhibitors were comprehensively investigated. JAK inhibitors were proved to be effectively improving disease condition within 3 months (12 weeks) in both PsA and AS. Besides, psoriasis-related dermal lesions could also be improved by JAK inhibitors. Dose-dependent effects suggested that higher dose tofacitinib could bring not only a higher level of treatment response but also more safety concerns.

CONCLUSION

JAK inhibitors were proved to be effective in improving arthritis symptoms and enhancing the quality of life in both PsA and AS patients. Compared with AS, JAK inhibitors seemed to perform better in PsA treatment. However, the frequency of adverse events PsA and AS in comparison with the placebo group showed no difference. Higher dose of tofacitinib could attain better treatment response without increasing adverse events in short-term follow-up.

KEY POINTS

• JAK inhibitors were proved to be effective in improving arthritis symptoms and enhancing the quality of life in both PsA and AS patients. • Compared with AS, JAK inhibitors seemed to perform better in PsA treatment. • The frequency of adverse events PsA and AS in comparison with the placebo group showed no difference. • Higher dose of tofacitinib could attain better treatment response without increasing adverse events in short-term follow-up.

JAK out of the Box; The Rationale behind Janus Kinase Inhibitors in the COVID-19 setting, and their potential in obese and diabetic populations

The adaptive use of Janus kinase (JAK)-inhibitors has been suggested by rheumatology experts in the management of COVID-19. We recount the rationale behind their use in this setting, and the current evidence for and against their use in this review. JAK-inhibitors role in COVID-19 infection appears to be multifaceted, including preventing viral endocytosis and dampening the effect of excessive chemokines. This drug class may be able to achieve these effects at already preapproved dosages. Concerns arise regarding reactivation of latent viral infections and the feasibility of their use in those with severe disease. Most interestingly, JAK-Inhibitors may also have an additional advantage for diabetic and obese populations, where the dysregulation of JAK-signal transducer and activator of transcription pathway may be responsible for their increased risk of poor outcomes. Targeting this pathway may provide a therapeutic advantage for these patient groups.

JAK/STAT pathway in pathology of rheumatoid arthritis (Review)

Rheumatoid arthritis (RA) is classified as an inflammatory, chronic autoimmune and disabling disease based on the intricate interplay between environmental and genetic factors. With a prevalence ranging from 0.3 to 1%, RA is the most prevalent inflammatory joint disease observed in adults. Disruption of immune tolerance becomes evident when abnormal stimulation of the innate and adaptive immune system occurs. This cascade of events causes persistent joint inflammation, proliferative synovitis and, ultimately, damage of the underlying cartilage as well as the subchondral bone, leading to permanent joint destruction, deformity and subsequent loss of function. With cytokines being the key to a multitude of biological processes, including inflammation, hematopoiesis and overall immune response, one must inevitably look at the main pathways through which a significant number of those molecules exert their function. Janus kinase/signal transducers and activators of transcription (JAK/STATs) represent one such pathway and, recently, JAK inhibitors (JAKinibs) have shown promise in the treatment of several inflammatory diseases, including RA. This narrative review focuses on the intricate signaling pathways involved as well as on the clinical aspects and safety profiles of JAKinibs approved for the treatment of RA.

JANEX-1 improves acute pulmonary embolism through VEGF and FAK in pulmonary artery smooth muscle cells

Accumulating evidence suggests that vascular remodeling due to immoderate proliferation and migration of SMCs is a common process occurring in APE. In this work, we tried to find a breakthrough in the pathological mechanism to alleviate the prognosis of APE by improving SMCs proliferation and explored the effect of JANEX-1 on PDGF-induced proliferation-related molecules in PVSMCs and assessed the therapeutic potential of JAK3 for vascular remodeling in APE mice. We demonstrated that JANEX-1, blocking JAK3 expression or activity, reduced JAK3/STAT3 signaling pathway, VEGF expression and FAK activation, and PDGF-induced proliferation of PVSMCs. Moreover, JANEX-1 inhibited the thrombus-induced intimal hyperplasia and the expression of VEGF and FAK activation in neointimal SMCs of APE mice. The data are helpful to elucidate the pharmacological mechanism and potential therapeutic effect of JANEX-1 in APE.

Systematic review on tuberculosis risk in patients with rheumatoid arthritis receiving inhibitors of Janus Kinases

INTRODUCTION

Janus kinases inhibitors (anti-JAKs), including tofacitinib, baricitinib, upadacitinib, and filgotinib, represent a new class of synthetic targeted drugs for the treatment of rheumatoid arthritis (RA). In this review, the risk of active tuberculosis (TB) occurrence in patients receiving anti-JAKs was assessed. The literature on this topic, updated to 29 February 2020 was reviewed. Overall, 40 reports (22 tofacitinib, 10 baricitinib, 5 upadacitinib, 3 filgotinib) were examined. A low frequency, not exceeding 0.25%, of active TB cases in patients were exposed to anti-JAKs. Only 1 of 89 recorded cases in tofactinib and baricitinib exposure occurred in countries at intermediate or high TB risk, and most of the cases probably were due to first mycobacterium tuberculosis (Mtb) exposure. Although no cases were observed in patients receiving upadacitinib and filgotinib, long-term trials and data from real-life are required to more precisely address the TB risk associated with the two drugs.

AREAS COVERED

Discussion on the TB risk associated with anti-JAKs, and on the need for accurate evaluation of host-related risk factors in high risk countries.

EXPERT OPINION

Available data on anti-JAKs suggest a negligible risk of active TB occurrence in low endemic areas.

Evaluating upadacitinib for the treatment of rheumatoid arthritis

INTRODUCTION

The introduction of JAKs inhibitors for the treatment of rheumatoid arthritis represents a promising new era in the management of the disease. New compounds under investigation, like upadacitinib, with greater selectivity for JAK1 inhibition have recently been approved for the treatment of adults with moderately to severely active rheumatoid arthritis who have had an inadequate response or intolerance to conventional synthetic disease-modifying antirheumatic drugs.

AREAS COVERED

Herein, the authors review the pharmacological data, the therapeutic efficacy, and safety data of upadacitinib before providing the reader with their critical evaluation and future perspectives.

EXPERT OPINION

Upadacitinib was able to accomplish all the primary and secondary end points in most of the trials, with a safety profile that is similar to the other JAK inhibitors. It has also demonstrated superiority over a tumor necrosis factor inhibitor and data on new indications is also favorable. Upadacitinib is a promising new drug for the treatment of rheumatoid arthritis.

GLOSSARY

Adalimumab: ADA; American College of Rheumatology: ACR; Assessment of Spondylarthritis International Society 40: ASAS40; Ankylosis Spondylitis: AS; Area under the Curve: AUC; Biological Disease-modifying arthritis drugs: bDMARDs; Clinical disease activity index: CDAI; C Reactive Protein: CRP; Conventional Synthetic Disease-modifying arthritis drugs: csDMARDs; Deep Venous Thrombosis: DVT; Disease arthritis score: DAS.

Therapeutic targeting of JAKs: from hematology to rheumatology and from the first to the second generation of JAK inhibitors

Several cytokines and growth factors, as well as their downstream signalling pathways, are implicated in the pathogenesis of haematological and immune-mediated diseases. These mediators act through binding to their cognate receptor and activation of one or more of the four Janus family tyrosine kinases (JAKs). Gene knock-out studies together with evidence from patients carrying activating mutant forms of JAKs (eg, JAK2 V617F in myeloproliferative disorders) provided strong rationale for the development of JAK inhibitors. Based on encouraging preclinical data showing the capacity of JAK inhibitors to suppress the signalling from multiple cytokines, an extensive drug development program was set out, with the initial successful introduction of tofacitinib, baricitinib and ruxolitinib in various chronic rheumatic and myeloproliferative diseases, respectively. Importantly, advancements with the design of next-generation, hyper-selective JAK inhibitors hold promise for the better control of inflammation, while reducing the risk for harms, in an expanding spectrum of medical disorders.

COVID-19 infection and rheumatoid arthritis: Faraway, so close!

The outbreak of the new coronavirus infections COVID-19 in December 2019 in China has quickly become a global health emergency. Given the lack of specific anti-viral therapies, the current management of severe acute respiratory syndrome coronaviruses (SARS-CoV-2) is mainly supportive, even though several compounds are now under investigation for the treatment of this life-threatening disease. COVID-19 pandemic is certainly conditioning the treatment strategy of a complex disorder as rheumatoid arthritis (RA), whose infectious risk is increased compared to the general population because of an overall impairment of immune system typical of autoimmune diseases combined with the iatrogenic effect generated by corticosteroids and immunosuppressive drugs. However, the increasing knowledge about the pathophysiology of SARS-CoV-2 infection is leading to consider some anti-rheumatic drugs as potential treatment options for the management of COVID-19. In this review we will critically analyse the evidences on either positive or negative effect of drugs commonly used to treat RA in this particular scenario, in order to optimize the current approach to RA patients.

Design, synthesis, and pharmacological evaluation of 4- or 6-phenyl-pyrimidine derivatives as novel and selective Janus kinase 3 inhibitors

As non-receptor tyrosine kinases, Janus kinases (JAKs) have become an attractive target for the treatment of autoimmune diseases and cancers. JAKs play a pivotal role in innate immunity, inflammation, and hematopoiesis by mediating the signaling of numerous cytokines, growth factors, and interferons (IFNs). Selective inhibitors of a variety of JAK members are expected to inhibit pro-inflammatory cytokine-mediated inflammation and immune responses, while preventing targeting other subtypes of JAKs. In this work, poorly selective compounds based on 4- or 6-phenyl-pyrimidine derivatives have been improved to highly potent and selective compounds by designing a covalent binding tether, which attaches to the unique cysteine (Cys909) residue in JAK3. Compound 12 exhibited potent JAK3 inhibitory activity (IC₅₀ = 1.7 nM) with an excellent selectivity profile when compared to the other JAK isoforms (>588-fold). In a cellular assay, compound 12 strongly inhibited JAK3-dependent signaling and T cell proliferation. Moreover, in vivo data revealed that compound 12 significantly suppressed oxazolone (OXZ)-induced delayed hypersensitivity responses in Balb/c mice. Compound 12 also displayed decent pharmacokinetic properties and was suitable for in vivo use. Taken together, these results indicated that compound 12 may be a promising tool compound as a selective JAK3 inhibitor for treating autoimmune diseases.