Comparison of Janus kinase inhibitors in the treatment of rheumatoid arthritis: a systemic literature review

Differential properties of Janus kinase inhibitors in the treatment of immune-mediated inflammatory diseases

Janus kinases (JAKs) are a family of cytosolic tyrosine kinases that regulate cytokine signal transduction, including cytokines involved in a range of inflammatory diseases, such as RA, psoriasis, atopic dermatitis and IBD. Several small-molecule JAK inhibitors (JAKis) are now approved for the treatment of various immune-mediated inflammatory diseases. There are, however, key differences between these agents that could potentially translate into unique clinical profiles. Each JAKi has a unique chemical structure, resulting in a distinctive mode of binding within the catalytic cleft of the target JAK, and giving rise to distinct pharmacological characteristics. In addition, the available agents have differing selectivity for JAK isoforms, as well as off-target effects against non-JAKs. Other differences include effects on haematological parameters, DNA damage repair, reproductive toxicity and metabolism/elimination. Here we review the pharmacological profiles of the JAKis abrocitinib, baricitinib, filgotinib, peficitinib, tofacitinib and upadacitinib.

Upadacitinib for the Treatment of Rheumatoid Arthritis: An Extensive Review

OBJECTIVES

To review the characteristics, efficacy, safety, pharmacoeconomics, and place in therapy of upadacitinib, a Janus kinase (JAK) inhibitor, in the treatment of rheumatoid arthritis (RA).

DATA SOURCES

PubMed (January 2003-May 2022) was searched using upadacitinib and ABT-494.

STUDY SELECTION AND DATA EXTRACTION

Human studies published in peer-reviewed publications in English were the primary sources for efficacy and safety data.

DATA SYNTHESIS

In randomized, double-blind, controlled clinical studies, upadacitinib demonstrated statistically significant improvement in RA symptoms as monotherapy and in combination with conventional synthetic disease-modifying antirheumatic drugs (csDMARDs) when compared with csDMARD monotherapy or to adalimumab or abatacept in combination with csDMARD therapy in patients with RA. American College of Rheumatology 20% response rates were 68% to 79% for upadacitinib monotherapy and 64% to 84% for upadacitinib plus csDMARD therapy, compared with 28% to 59% for csDMARD-only therapy and 63% to 74% for biologic DMARD (bDMARD) plus csDMARD therapy. Long-term extension studies demonstrated similar findings. Upadacitinib had similar rates of serious infections, herpes zoster, major cardiovascular events, and venous thromboembolic events as other JAK inhibitors. Upadacitinib was similar in cost to tofacitinib and twice as high as baricitinib based on current estimated costs to patients, but actual costs may vary.

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE

Upadacitinib is an alternative therapy to other JAK inhibitors and bDMARDs in patients with moderate to severe RA who have had an inadequate response to a tumor necrosis factor inhibitor alone or in combination with a csDMARD.

CONCLUSIONS

Upadacitinib is an effective JAK inhibitor for use in RA.

Rheumatoid arthritis: advances in treatment strategies

Rheumatoid arthritis (RA) is characterised by severe joint and bone damage due to heightened autoimmune response at the articular sites. Worldwide annual incidence and prevalence rate of RA is 3 cases per 10,000 population and 1%, respectively. Several genetic and environmental (microbiota, smoking, infectious agents) factors contribute to its pathogenesis. Although convention treatment strategies, predominantly Disease Modifying Anti Rheumatic Drugs (DMARDs) and Glucocorticoids (GC), are unchanged as the primary line of treatment; novel strategies consisting of biological DMARDs, are being developed and explored. Personalized approaches using biologicals targetspecific pathways associated with disease progression. However, considering the economic burden and side-effects associated with these, there is an unmet need on strategies for early stratification of the inadequate responders with cDMARDs. As RA is a complex disease with a variable remission rate, it is important not only to evaluate the current status of drugs in clinical practice but also those with the potential of personalised therapeutics. Here, we provide comprehensive data on the treatment strategies in RA, including studies exploring various combination strategies in clinical trials. Our systematic analysis of current literature found that conventional DMARDs along with glucocorticoid may be best suited for early RA cases and a combination of conventional and targeted DMARDs could be effective for treating seronegative patients with moderate to high RA activity. Clinical trials with insufficient responders to Methotrexate suggest that adding biologicals may help in such cases. However, certain adverse events associated with the current therapy advocate exploring novel therapeutic approaches such as gene therapy, mesenchymal stem cell therapy in future.

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.

Safety and efficacy in the nursing care of people with rheumatic diseases on janus kinase inhibitor therapy

Nurses's support of patients needs an evidence base as much as that of specialists management. However, some more practical aspects need specific questions that are not addressed in medical societies' recommendations. Our objective was to investigate the effect of Janus kinase inhibitors (jakinibs) on efficacy, safety, infections, cardiovascular risk, vaccination, pregnancy and lactation, interactions, surgery, and switch in adult patients with rheumatic diseases. We used the methodology for rapid reviews. Medline was searched for systematic reviews of randomised clinical trials and longitudinal observational studies reporting on the target aspects, without limits, yielding 540 titles, of which 70 articles were selected for detailed reading after the screening of title and abstract. In the case of no systematic review being published on a specific question, we resorted to the information provided by primary studies. The efficacy and safety profiles are similar to that of TNF-inhibitors to which they are compared in most studies; however, there is an increased risk of herpes zoster infections with jakinibs. The evidence on pregnancy, surgery and switches between jakinibs is very limited, although, so far, there are no major issues to inform patients about or to implement specific measures. In general, evidence to support nursing management in patients being treated with jakinibs is of moderate quality and scarce, ought to the recent incursion of jakinibs as a treatment.

Indications and effects of biological agents in the treatment of noninfectious uveitis

Noninfectious uveitis is a common blinding eye disease, and an autoimmune response is involved in its pathogenesis. Biological agents have gradually been introduced into the treatment of noninfectious uveitis. The authors reviewed the clinical application and side effects of different biological agents on noninfectious uveitis. Biological agents that target TNF-α are widely used in the clinic. Other biological agents, such as IL-6- and IL-1-neutralizing antibodies, are used in patients who do not respond to TNF inhibitors. The efficacy of IL-17 neutralizing antibodies in noninfectious uveitis is controversial. Biological agents targeting T cells and signaling pathways provide new drug options for treatment of noninfectious uveitis. However, it cannot be ignored that these biological agents have side effects, such as increasing risk of infection.

Rheumatoid Arthritis and JAK-STAT Inhibitors: Prospects of Topical Delivery

Abstract:

Rheumatoid arthritis (RA) is the most common musculoskeletal disease in the world. The clinical prospects have increased tremendously since the advent of biological agents as therapy options. NSAIDs such as indomethacin, celecoxib, and etoricoxib are used often in the treatment of RA but off-target effects decreased their use. DMARDs such as methotrexate and etanercept were also effective in the treatment of RA, but tolerance to methotrexate developed in many cases. Janus kinase inhibitors (JAKi) have also gained popularity as a treatment option for rheumatoid arthritis. Tofacitinib is the foremost JAK inhibitor that is used to treat RA as an individual agent or in combination with other DMARDs. The most frequently used route of administration for JAKi is oral. Since oral formulations of JAK inhibitors have a number of health hazards, such as systemic toxicity and patient noncompliance, topical formulations of JAK inhibitors have emerged as a preferable alternative for administering JAK inhibitors. Tofacitinib delivered topically, seems to have the potential to eliminate or reduce the occurrences of negative effects when compared to tofacitinib taken orally. Given the scarcity of knowledge on the techniques for topical distribution of JAKi, more effort will be required to develop a stable topical formulation of JAKi to address the limitations of oral route. The current review looks at JAK inhibitors and the ways that have been used to generate topical formulations of them.

Targeted and activatable nanosystem for fluorescent and optoacoustic imaging of immune-mediated inflammatory diseases and therapy via inhibiting NF-κB/NLRP3 pathways

Immune-mediated inflammatory diseases (IMIDs) represent a diverse group of diseases and challenges remain for the current medications. Herein, we present an activatable and targeted nanosystem for detecting and imaging IMIDs foci and treating them through blocking NF-κB/NLRP3 pathways. A ROS-activatable prodrug BH-EGCG is synthesized by coupling a near-infrared chromophore with the NF-κB/NLRP3 inhibitor epigallocatechin-3-gallate (EGCG) through boronate bond which serves as both the fluorescence quencher and ROS-responsive moiety. BH-EGCG molecules readily form stable nanoparticles in aqueous medium, which are then coated with macrophage membrane to ensure the actively-targeting capability toward inflammation sites. Additionally, an antioxidant precursor N-acetylcysteine is co-encapsulated into the coated nanoparticles to afford the nanosystem BH-EGCG&NAC@MM to further improve the anti-inflammatory efficacy. Benefiting from the inflammation-homing effect of the macrophage membrane, the nanosystem delivers payloads (diagnostic probe and therapeutic drugs) to inflammatory lesions more efficiently and releases a chromophore and two drugs upon being triggered by the overexpressed in-situ ROS, thus exhibiting better theranostic performance in the autoimmune hepatitis and hind paw edema mouse models, including more salient imaging signals and better therapeutic efficacy via inhibiting NF-κB pathway and suppressing NLRP3 inflammasome activation. This work may provide perceptions for designing other actively-targeting theranostic nanosystems for various inflammatory diseases.

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.

The KRAS-regulated kinome identifies WEE1 and ERK coinhibition as a potential therapeutic strategy in KRAS-mutant pancreatic cancer

Oncogenic KRAS drives cancer growth by activating diverse signaling networks, not all of which have been fully delineated. We set out to establish a system-wide profile of the KRAS-regulated kinase signaling network (kinome) in KRAS-mutant pancreatic ductal adenocarcinoma (PDAC). We knocked down KRAS expression in a panel of six cell lines and then applied multiplexed inhibitor bead/MS to monitor changes in kinase activity and/or expression. We hypothesized that depletion of KRAS would result in downregulation of kinases required for KRAS-mediated transformation and in upregulation of other kinases that could potentially compensate for the deleterious consequences of the loss of KRAS. We identified 15 upregulated and 13 downregulated kinases in common across the panel of cell lines. In agreement with our hypothesis, all 15 of the upregulated kinases have established roles as cancer drivers (e.g., SRC, TGF-β1, ILK), and pharmacological inhibition of one of these upregulated kinases, DDR1, suppressed PDAC growth. Interestingly, 11 of the 13 downregulated kinases have established driver roles in cell cycle progression, particularly in mitosis (e.g., WEE1, Aurora A, PLK1). Consistent with a crucial role for the downregulated kinases in promoting KRAS-driven proliferation, we found that pharmacological inhibition of WEE1 also suppressed PDAC growth. The unexpected paradoxical activation of ERK upon WEE1 inhibition led us to inhibit both WEE1 and ERK concurrently, which caused further potent growth suppression and enhanced apoptotic death compared with WEE1 inhibition alone. We conclude that system-wide delineation of the KRAS-regulated kinome can identify potential therapeutic targets for KRAS-mutant pancreatic cancer.

Risk of herpes zoster in patients with rheumatoid arthritis in the biologics era from 2011 to 2015 and its association with methotrexate, biologics, and corticosteroids

OBJECTIVES

To elucidate the incidence and risk factors of herpes zoster (HZ) in patients with rheumatoid arthritis (RA) in the biologics era.

METHODS

We determined the rate of HZ occurrence among the RA patients that participated in the Institute of Rheumatology, Rheumatoid Arthritis surveys from 2011 to 2015, by assessing medical records. The standardised incidence rate per 1000 patient-years with a 95% confidence interval (CI) was calculated, and risk factors for HZ were analysed using a time-dependent Cox regression analysis.

RESULTS

Among 7815 patients (female, 84.7%) contributing to 25,863 patient-years of observation, 340 HZ events in 309 patients were confirmed. The standardised incidence rate (95% CI) per 1000 patient-years was 8.5 (6.9-10.5) in total, 6.0 (3.7-9.2) in men, and 11.0 (8.7-13.7) in women. Risk factors for HZ were age per 10 years (hazard ratio 1.14, 95% CI 1.03-1.26, p < .05), Japanese version of the Health Assessment Questionnaire (J-HAQ) score of 0.5-1.5 (versus J-HAQ = 0; 1.51, 1.09-2.10, p < .05), methotrexate use (1.58, 1.06-2.36, p < .05), and biologic use (1.88, 1.44-2.47, p < .01).

CONCLUSIONS

In the era when biologics were frequently used and corticosteroid use and doses were decreasing, methotrexate and biologics increased the risk for HZ.

Current and future status of JAK inhibitors

An enhanced understanding of the importance of Janus kinase (JAK) and signal transducer and activator of transcription (STAT) signalling in multiple disease states has led to an increasing applicability of therapeutic intervention with JAK inhibitors. These agents have revolutionised treatments for a heterogeneous group of disorders, such as myeloproliferative neoplasms, rheumatoid arthritis, inflammatory bowel disease, and multiple immune-driven dermatological diseases, exemplifying rapid bench-to-bedside translation. In this Therapeutics paper, we summarise the currently available data concerning the successes and safety of an array of JAK inhibitors and hypothesise on how these fields could develop.

Management of Fatigue in Rheumatoid Arthritis

Fatigue in rheumatoid arthritis is highly prevalent. It is correlated only weakly with disease activity but more so with pain, mood, personality features, poor sleep, obesity and comorbidities. Fatigue can be measured by many standardised questionnaires and more easily with a Visual Analogue Scale or numeric rating scale. Most patients with RA have some fatigue, and at least one in six have severe fatigue. Chronic pain and depressed mood are also common in RA patients with significant fatigue. It affects function and quality of life and is worse on average in women. Evidence-based treatment for fatigue includes treatment of underlying disease activity (with on average modest improvement of fatigue), exercise programmes and supervised self-management programmes with cognitive-behavioural therapy, mindfulness and reinforcement (such as reminders). The specific programmes for exercise and behavioural interventions are not standardised. Some medications cause fatigue such as methotrexate. More research is needed to understand fatigue and how to treat this common complex symptom in RA that can be the worst symptom for some patients.

Comparative Efficacy and Safety of Peficitinib Versus Tofacitinib and Baricitinib for Treatment of Rheumatoid Arthritis: A Systematic Review and Network Meta-Analysis

INTRODUCTION

Peficitinib, a Janus kinase (JAK) inhibitor, is approved for clinical use in Japan, Korea, and Taiwan, but head-to-head comparisons versus other JAK inhibitors are lacking. We indirectly compared peficitinib, tofacitinib, and baricitinib for rheumatoid arthritis treatment.

METHODS

We searched MEDLINE, Embase, the Cochrane Central Register of Controlled Trials, ClinicalTrials.gov, and congress archives up until February 12, 2019, for randomized controlled trials of peficitinib, tofacitinib, and baricitinib. Efficacy (American College of Rheumatology responses, disease activity scores, modified total Sharp score, Simplified Disease Activity Index [SDAI]) and safety outcomes were compared using a Bayesian network meta-analysis. The Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) consensus was followed for reporting results. A network meta-regression assessed the impact on outcomes of proportions of patients receiving concomitant methotrexate or of Asian ethnicity.

RESULTS

The network meta-analysis included 21 randomized controlled trials. At 12 weeks, all evaluable efficacy outcomes were comparable or improved with peficitinib 150 mg and 100 mg once daily, versus baricitinib 2 and 4 mg once daily and tofacitinib 5 mg twice daily. At 24 weeks, efficacy outcomes were comparable or improved for each peficitinib dose versus baricitinib and tofacitinib. Risk of adverse events and serious adverse events at 12 weeks were similar with peficitinib 100 and 150 mg versus baricitinib and tofacitinib. The proportion of patients receiving concomitant methotrexate had no effect on any outcome analyzed, but Asian ethnicity had a positive effect on multiple efficacy outcomes.

CONCLUSIONS

Peficitinib had comparable efficacy versus tofacitinib and baricitinib for reduction in disease activity as measured by SDAI, and for reduction in progression of joint damage as measured radiographically. No notable differences in safety outcomes were observed. Further studies are required to better characterize the impact of ethnicity on the efficacy of JAK inhibitors.

Frequency of Prescription Claims for Drugs that May Interact with Janus Kinase Inhibitors Among Patients with Rheumatoid Arthritis in the US

Introduction

This study describes the frequency of prescription claims for drugs that may interact with Janus kinase (JAK) inhibitors among adult patients with rheumatoid arthritis (RA) in a large US claims database.

Methods

This observational, retrospective, cross-sectional study of the IBM^® MarketScan^® Research Commercial and the Medicare Supplemental Database included adults (≥ 18 years) with ≥ 2 outpatient claims 30 or more days apart or ≥ 1 inpatient visit claim with an RA diagnosis between January 1, 2013 and March 31, 2017 (the index period). During the study period, from January 1, 2013 to March 31, 2018, strong organic anion transporter (OAT3) inhibitors, strong cytochrome P450 (CYP) 3A4 inhibitors, and moderate or strong CYP3A4 inhibitors in combination with strong CYP2C19 inhibitors, were identified as drugs with potential for drug–drug interactions (DDIs) with JAK inhibitors approved for RA treatment in the US. Descriptive statistics were conducted.

Results

A total of 152,853 patients met eligibility criteria. Approximately 76% were women and the median age was 57 years. Of these patients, < 0.1% had a claim for a strong OAT3 inhibitor, and 1% had claims for the combination of a strong CYP3A4 and strong CYP2C19 inhibitor; 3% of patients had a claim for a strong CYP3A4 inhibitor and almost 10% had claims for both a moderate CYP3A4 and a strong CYP2C19 inhibitor.

Conclusions

Up to 10% of RA patients have been prescribed a drug with a potential JAK interaction. Rheumatologists should consider potential DDIs when managing patients with RA.

Points to consider for the treatment of immune-mediated inflammatory diseases with Janus kinase inhibitors: a consensus statement

OBJECTIVES

Janus kinase inhibitors (JAKi) have been approved for use in various immune-mediated inflammatory diseases. With five agents licensed, it was timely to summarise the current understanding of JAKi use based on a systematic literature review (SLR) on efficacy and safety.

METHODS

Existing data were evaluated by a steering committee and subsequently reviewed by a 29 person expert committee leading to the formulation of a consensus statement that may assist the clinicians, patients and other stakeholders once the decision is made to commence a JAKi. The committee included patients, rheumatologists, a gastroenterologist, a haematologist, a dermatologist, an infectious disease specialist and a health professional. The SLR informed the Task Force on controlled and open clinical trials, registry data, phase 4 trials and meta-analyses. In addition, approval of new compounds by, and warnings from regulators that were issued after the end of the SLR search date were taken into consideration.

RESULTS

The Task Force agreed on and developed four general principles and a total of 26 points for consideration which were grouped into six areas addressing indications, treatment dose and comedication, contraindications, pretreatment screening and risks, laboratory and clinical follow-up examinations, and adverse events. Levels of evidence and strengths of recommendations were determined based on the SLR and levels of agreement were voted on for every point, reaching a range between 8.8 and 9.9 on a 10-point scale.

CONCLUSION

The consensus provides an assessment of evidence for efficacy and safety of an important therapeutic class with guidance on issues of practical management.

Points to consider for the treatment of immune-mediated inflammatory diseases with Janus kinase inhibitors: a consensus statement

OBJECTIVES

Janus kinase inhibitors (JAKi) have been approved for use in various immune-mediated inflammatory diseases. With five agents licensed, it was timely to summarise the current understanding of JAKi use based on a systematic literature review (SLR) on efficacy and safety.

METHODS

Existing data were evaluated by a steering committee and subsequently reviewed by a 29 person expert committee leading to the formulation of a consensus statement that may assist the clinicians, patients and other stakeholders once the decision is made to commence a JAKi. The committee included patients, rheumatologists, a gastroenterologist, a haematologist, a dermatologist, an infectious disease specialist and a health professional. The SLR informed the Task Force on controlled and open clinical trials, registry data, phase 4 trials and meta-analyses. In addition, approval of new compounds by, and warnings from regulators that were issued after the end of the SLR search date were taken into consideration.

RESULTS

The Task Force agreed on and developed four general principles and a total of 26 points for consideration which were grouped into six areas addressing indications, treatment dose and comedication, contraindications, pretreatment screening and risks, laboratory and clinical follow-up examinations, and adverse events. Levels of evidence and strengths of recommendations were determined based on the SLR and levels of agreement were voted on for every point, reaching a range between 8.8 and 9.9 on a 10-point scale.

CONCLUSION

The consensus provides an assessment of evidence for efficacy and safety of an important therapeutic class with guidance on issues of practical management.

The JAK1 Selective Inhibitor ABT 317 Blocks Signaling Through Interferon-γ and Common γ Chain Cytokine Receptors to Reverse Autoimmune Diabetes in NOD Mice

Cytokines that signal through the JAK-STAT pathway, such as interferon-γ (IFN-γ) and common γ chain cytokines, contribute to the destruction of insulin-secreting β cells by CD8⁺ T cells in type 1 diabetes (T1D). We previously showed that JAK1/JAK2 inhibitors reversed autoimmune insulitis in non-obese diabetic (NOD) mice and also blocked IFN-γ mediated MHC class I upregulation on β cells. Blocking interferons on their own does not prevent diabetes in knockout NOD mice, so we tested whether JAK inhibitor action on signaling downstream of common γ chain cytokines, including IL-2, IL-7 IL-15, and IL-21, may also affect the progression of diabetes in NOD mice. Common γ chain cytokines activate JAK1 and JAK3 to regulate T cell proliferation. We used a JAK1-selective inhibitor, ABT 317, to better understand the specific role of JAK1 signaling in autoimmune diabetes. ABT 317 reduced IL-21, IL-2, IL-15 and IL-7 signaling in T cells and IFN-γ signaling in β cells, but ABT 317 did not affect GM-CSF signaling in granulocytes. When given in vivo to NOD mice, ABT 317 reduced CD8⁺ T cell proliferation as well as the number of KLRG⁺ effector and CD44^hiCD62L^lo effector memory CD8⁺ T cells in spleen. ABT 317 also prevented MHC class I upregulation on β cells. Newly diagnosed diabetes was reversed in 94% NOD mice treated twice daily with ABT 317 while still on treatment at 40 days and 44% remained normoglycemic after a further 60 days from discontinuing the drug. Our results indicate that ABT 317 blocks common γ chain cytokines in lymphocytes and interferons in lymphocytes and β cells and are thus more effective against diabetes pathogenesis than IFN-γ receptor deficiency alone. Our studies suggest use of this class of drug for the treatment of type 1 diabetes.

Pharmacokinetics, Pharmacodynamics, and Safety of Peficitinib (ASP015K) in Healthy Male Caucasian and Japanese Subjects

BACKGROUND AND OBJECTIVE

Peficitinib pharmacokinetics and pharmacodynamics have been characterized mainly in Caucasian subjects. This study investigated the pharmacokinetics, pharmacodynamics, safety, and tolerability of peficitinib in healthy Japanese subjects compared with Caucasian subjects.

METHODS

In this single-center, randomized, double-blind, placebo-controlled study, a cohort of healthy Japanese (n = 24) and Caucasian (n = 24) men received a single oral dose of peficitinib (20, 60, or 200 mg) or placebo. Another cohort of Japanese men (n = 24) received peficitinib (10, 30, or 100 mg) or placebo twice daily for 7 days. Pharmacokinetic and pharmacodynamic parameters were assessed, and adverse events (AEs) monitored throughout.

RESULTS

Dose proportionality of maximum plasma drug concentration (C_max) and area under the plasma concentration-time curve extrapolated to infinity (AUC_inf) was demonstrated for both ethnicities. The geometric mean ratio for dose-normalized C_max was 45.7-98.8% higher and AUC_inf was 33.8-66.4% higher in Japanese versus Caucasian subjects. Mean peak inhibition of STAT5 phosphorylation was higher in Japanese than Caucasian subjects for a given peficitinib dose, but inhibition was comparable across ethnicities for a given plasma peficitinib concentration. In the multiple-dose study, plasma peficitinib concentrations were similar on day 1 and day 7. All AEs were mild, and none resulted in study discontinuation.

CONCLUSIONS

Peficitinib was well tolerated at doses up to 200 mg daily for 7 days in healthy Japanese subjects. Dose-proportional exposure was demonstrated across the single-dose range of 20-200 mg, with greater peficitinib exposure in Japanese compared with Caucasian subjects. The pharmacokinetic/pharmacodynamic relationships were considered comparable between these populations. CLINICALTRIALS.

GOV IDENTIFIER

NCT01225224.

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.

JAK-Inhibitors for the Treatment of Rheumatoid Arthritis: A Focus on the Present and an Outlook on the Future

Janus kinase inhibitors (JAKi) belong to a new class of oral targeted disease-modifying drugs which have recently revolutionized the therapeutic panorama of rheumatoid arthritis (RA) and other immune-mediated diseases, placing alongside or even replacing conventional and biological drugs. JAKi are characterized by a novel mechanism of action, consisting of the intracellular interruption of the JAK-STAT pathway crucially involved in the immune response. The aim of this narrative review is to globally report the most relevant pharmacological features and clinical outcomes of the developed and incoming JAKi for RA, based on the available preclinical and clinical evidence. A total of 219 papers, including narrative and systematic reviews, randomized controlled trials (RCTs), observational studies, case reports, guidelines, and drug factsheets, were selected. The efficacy and safety profile of both the first generation JAKi (baricitinib and tofacitinib) and the second generation JAKi (upadacitinib, filgotinib, peficitinib, decernotinib and itacitinib) were compared and discussed. Results from RCTs and real-life data are encouraging and outline a rapid onset of the pharmacologic effects, which are maintained during the time. Their efficacy and safety profile are comparable or superior to those of biologic agents and JAKi proved to be efficacious when given as monotherapy. Finally, the manufacturing of JAKi is relatively easier and cheaper than that of biologics, thus increasing the number of compounds being formulated and tested for clinical use.

BARICITINIB: NEW PHARMACOTHERAPY OPTIONS FOR RHEUMATOID ARTHRITIS AND OTHER IMMUNE-MEDIATED INFLAMMATORY RHEUMATIC DISEASES

Deciphering the mechanisms of the pathogenesis of immune-mediated inflammatory rheumatic diseases (IMIRDs) in conjunction with designing a wide range of biological agents is one of the major medical advances in the 21st century. A new promising area of pharmacotherapy for IMIRDs is associated with the design of the so-called targeted oral medications that primarily include Janus kinase (JAK) inhibitors. The review presents new data on the efficacy and safety of the new JAK inhibitor baricitinib in treating rheumatoid arthritis and other IMIRDs.

Deficiency of STING Promotes Collagen-Specific Antibody Production and B Cell Survival in Collagen-Induced Arthritis

The levels of interferon-alpha are high in the serum and synovial fluid of rheumatoid arthritis (RA) patients. Activation of the stimulator of type I interferon genes (STING) mediates the productions of type I interferon and promotes chronic inflammation. STING plays a significant role in autoimmune lupus mice. However, the function of STING in collagen-induced arthritis (CIA) model has never been described. This study aimed to test the function of STING in CIA. The Sting-deficient mice developed arthritis comparable to WT mice. The levels of anti-collagen antibody from Sting-deficient mice were significantly higher than the WT mice. The B cells derived from Sting-deficient mice showed better survival than WT mice in response to the B cell receptor (BCR) stimulation. Activation of STING also induced B cell death, especially in activated B cells. This study demonstrated that the inhibition of STING promotes anti-collagen antibodies and B cell survival, which suggested that STING acts as a negative regulator of B cell function in the CIA model.

Peficitinib for the treatment of rheumatoid arthritis: an overview from clinical trials

INTRODUCTION

The treatment of rheumatoid arthritis (RA), a chronic, systemic, autoimmune disease, has been greatly advanced by the introduction of biologic disease-modifying antirheumatic drugs (DMARDs); however, many patients still fail to achieve disease remission. Peficitinib, an orally bioavailable inhibitor of the Janus kinase (JAK) receptor family, was approved in Japan in 2019 and Korea in 2020 for the treatment of RA.

AREAS COVERED

This review provides an overview of JAK inhibitors currently marketed or in development; the pharmacodynamics and pharmacokinetics of peficitinib; and the efficacy and safety data for peficitinib from Phase 2b and 3 trials.

EXPERT OPINION

Peficitinib has proven clinical efficacy in Asian patients (Japan, Korea, and Taiwan) with RA who have an inadequate response to conventional DMARDs. In Phase 3 trials, clinical improvements and prevention of joint destruction were demonstrated for both 100 mg and 150 mg once-daily peficitinib versus placebo, and treatment for up to 52 weeks was well tolerated. Safety signals, in particular the increased incidence of herpes zoster-related disease, appeared in line with other JAK inhibitors. Post-launch monitoring will establish the long-term safety and effectiveness of this drug, and further studies are necessary to determine its potential use in non-Asian populations.

Fenebrutinib versus Placebo or Adalimumab in Rheumatoid Arthritis: A Randomized, Double-Blind, Phase II Trial (ANDES Study)

OBJECTIVE

To evaluate fenebrutinib, an oral and highly selective non-covalent inhibitor of Bruton's tyrosine kinase (BTK), in patients with active rheumatoid arthritis (RA).

METHODS

Patients with RA and inadequate response to methotrexate (cohort 1, n=480) were randomized to fenebrutinib (50 mg once daily, 150 mg once daily, 200 mg twice daily), 40 mg adalimumab every other week, or placebo. Patients with RA and inadequate response to tumor necrosis factor inhibitors (cohort 2, n=98) received fenebrutinib (200 mg twice daily) or placebo. Both cohorts continued methotrexate therapy.

RESULTS

In cohort 1, American College of Rheumatology scores (ACR50) at week 12 were similar for fenebrutinib 50 mg once daily and placebo, and higher for fenebrutinib 150 mg once daily (28%) and 200 mg twice daily (35%) than placebo (15%) (p=0.017; p=0.0003). Fenebrutinib 200 mg twice daily and adalimumab (36%) were comparable (p=0.81). In cohort 2, more patients achieved ACR50 with fenebrutinib 200 mg twice daily (25%) than placebo (12%) (p=0.072). The most common adverse events for fenebrutinib included nausea, headache, anemia, and upper respiratory tract infections. Fenebrutinib had significant effects on myeloid and B cell biomarkers (CCL4 and rheumatoid factor). Fenebrutinib and adalimumab caused overlapping as well as distinct changes in B cell and myeloid biomarkers.

CONCLUSION

Fenebrutinib demonstrated efficacy comparable to adalimumab in patients with an inadequate response to methotrexate, and safety consistent with existing immunomodulatory therapies for RA. These data support targeting both B and myeloid cells via this novel mechanism for potential efficacy in the treatment of RA.

JAK inhibitors in refractory juvenile idiopathic arthritis-associated uveitis

To present our preliminary experience with JAK inhibitors in treating patients affected by juvenile idiopathic arthritis (JIA) and associated uveitis. Case series. Four consecutive patients with long-term history of juvenile idiopathic arthritis and severe associated uveitis were included in the study. Indication for treatment with JAK inhibitors was uncontrolled arthritis and/or uveitis despite different treatments with conventional and biologic disease modifying antirheumatic drugs (DMARDs). While on treatment with JAK inhibitors, namely, baricitinib (three cases) and tofacitinib (one case), all our patients showed improvement of uveitis defined as a reduction of intraocular inflammation according to Standardized Uveitis Nomenclature criteria. However, we observed a different response to treatment between the uveitis and the articular disease, as the latter did not respond as favorably as the former. Overall, the treatment was well tolerated by all patients and no ocular discomfort, ocular side effects, or allergic reactions were registered. JAK inhibitors may provide a new valuable treatment option in the therapeutic armamentarium for patients affected with JIA-associated uveitis, particularly in those refractory cases that are not adequately responding to conventional or biologic DMARDs.Key Points• A subset of patients with JIA uveitis either remain unresponsive or experience loss of efficacy• JAK inhibitors may provide a new valuable treatment option in JIA patients with uveitis• The safety profile was good with no occurrence of systemic side effects.