Efficacy and safety of the oral Janus kinase inhibitor peficitinib (ASP015K) monotherapy in patients with moderate to severe rheumatoid arthritis in Japan: a 12-week, randomised, double-blind, placebo-controlled phase IIb study

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Cumulative incidence and risk of infection in patients with rheumatoid arthritis treated with janus kinase inhibitors: A systematic review and meta-analysis

Patients with rheumatoid arthritis (RA) who receive immunosuppressive medications have a heightened risk of infection. The goal of our study was to calculate the pooled cumulative incidence and risk of infection in patients with RA treated with Janus kinase inhibitors (JAKi). The PubMed and EMBASE databases were queried for randomized controlled trials comparing patients with RA treated with JAKi (upadacitinib, baricitinib, tofacitinib, peficitinib, or filgotinib), defined as the treatment group, compared with control subjects, defined as participants receiving placebo or treatment regimen that was similar to that of participants in the treatment group, with the exception of JAKi. The primary study endpoint was the relative risk (RR) of any-grade and severe infection. The secondary endpoints were RR and cumulative incidence of opportunistic infections, herpes zoster, and pneumonia. The Stata v17 software was used for all data analysis. Results showed that treatment with baricitinib was associated with an increased risk of any-grade (RR 1.34; 95% CI: 1.19-1.52) and opportunistic (RR 2.69; 95% CI: 1.22-5.94) infection, whereas treatment with filgotinib (RR 1.21; 95% CI: 1.05-1.39), peficitinib (RR 1.40; 95% CI: 1.05-1.86) and upadacitinib (RR 1.30; 95% CI: 1.09-1.56) was associated with increased risk of any-grade infection only. Analysis based on type of infection showed a pooled cumulative incidence of 32.44% for any-grade infections, 2.02% for severe infections, 1.74% for opportunistic infections, 1.56% for herpes zoster, and 0.49% for pneumonia in patients treated with any JAKi during the follow-up period. Treatment with specific JAKi in patients with RA is associated with an increased risk of any-grade and opportunistic infections but not severe infection. Close clinical monitoring of patients with RA treated with JAKi is required to establish the long-term infection risk profile of these agents.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

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

Background

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

Methods

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

Results

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

Conclusion

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

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Medicinal chemistry perspective of JAK inhibitors: synthesis, biological profile, selectivity, and structure activity relationship

JAK-STAT signalling pathway was discovered more than quarter century ago. The JAK-STAT pathway protein is considered as one of the crucial hubs for cytokine secretion which mediates activation of different inflammatory, cellular responses and hence involved in different etiological factors. The various etiological factors involved are haematopoiesis, immune fitness, tissue repair, inflammation, apoptosis, and adipogenesis. The presence of the active mutation V617K plays a significant role in the progression of the JAK-STAT pathway-related disease. Consequently, targeting the JAK-STAT pathway could be a promising therapeutic approach for addressing a range of causative factors. In this current review, we provided a comprehensive discussion for the in-detail study of anatomy and physiology of the JAK-STAT pathway which contributes structural domain rearrangement, activation, and negative regulation associated with the downstream signaling pathway, relationship between different cytokines and diseases. This review also discussed the recent development of clinical trial entities. Additionally, this review also provides updates on FDA-approved drugs. In the current investigation, we have classified recently developed small molecule inhibitors of JAK-STAT pathway according to different chemical classes and we emphasized their synthetic routes, biological evaluation, selectivity, and structure-activity relationship.

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

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

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

Background

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

Methods

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

Findings

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

Interpretation

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

Funding

Astellas Pharma.

Conjoint research of WGCNA, single-cell transcriptome and structural biology reveals the potential targets of IDD development and treatment and JAK3 involvement

OBJECTIVES

This study conducted integrated analysis of bulk RNA sequencing, single-cell RNA sequencing and Weighted Gene Co-expression Network Analysis (WGCNA), to comprehensively decode the most essential genes of intervertebral disc degeneration (IDD); then mainly focused on the JAK3 macromolecule to identify natural compounds to provide more candidate drug options in alleviating IDD.

METHODS

In the first part, we performed single-cell transcriptome analysis and WGCNA workflow to delineate the most pivotal genes of IDD. Then series of structural biology approaches and high-throughput virtual screening techniques were performed to discover potential compounds targeting JAK-STAT signaling pathway, such as Libdock, ADMET, precise molecular docking algorithm and in-vivo drug stability assessment.

RESULTS

Totally 4 hub genes were determined in the development of IDD, namely VEGFA, MMP3, TNFSF11, and TIMP3, respectively. Then, 3 novel natural materials, ZINC000014952116, ZINC000003938642 and ZINC000072131515, were determined as potential compounds, with less toxicities and moderate ADME characteristics. In-vivo drug stability assessment suggested that these drugs could interact with JAK3, and their ligand-JAK3 complexes maintained the homeostasis in-vivo, which acted as regulatory role to JAK3 protein. Among them, ZINC000072131515, also known as Menaquinone, demonstrated significant protective roles to alleviate the progression of IDD in vitro, which proved the nutritional therapy in alleviating IDD.

CONCLUSIONS

This study reported the essential genes in the development of IDD, and also the roles of Menaquinone to ameliorate IDD through inhibiting JAK3 protein. This study also provided more options and resources on JAK3 targeted screening, which may further expand the drug resources in the pharmaceutical market.

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

OBJECTIVE

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

METHOD

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

RESULTS

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

CONCLUSION

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

Double-edged sword of JAK/STAT signaling pathway in viral infections: novel insights into virotherapy

The Janus kinase/signal transducer and activator of transcription (JAK/STAT) is an intricate signaling cascade composed of various cytokines, interferons (IFN, growth factors, and other molecules. This pathway provides a delicate mechanism through which extracellular factors adjust gene expression, thereby acting as a substantial basis for environmental signals to influence cell growth and differentiation. The interactions between the JAK/STAT cascade and antiviral IFNs are critical to the host's immune response against viral microorganisms. Recently, with the emergence of therapeutic classes that target JAKs, the significance of this  cascade has been recognized in an unprecedented way. Despite the functions of the JAK/STAT pathway in adjusting immune responses against viral pathogens, a vast body of evidence proposes the role of this cascade in the replication and pathogenesis of viral pathogens. In this article, we review the structure of the JAK/STAT signaling cascade and its role in immuno-inflammatory responses. We also highlight the paradoxical effects of this pathway in the pathogenesis of viral infections. Video Abstract.

Oral small molecule agents in management of ulcerative colitis: fact or fancy?

Ulcerative colitis is a chronic, immune-mediated disease characterized by recurring episodes of mucosal inflammation in the colon and rectum. The primary pathogenic mechanism of ulcerative colitis is the dysregulation of the mucosal immune response. The disease follows a relapsing-remitting course, and the goal of management is to successfully induce and then maintain remission. Effectively managing this chronic disease requires addressing all aspects of it. Currently, we have various antitumor necrosis factor agents and novel biologics available for treating ulcerative colitis patients with moderate-to-severe disease. However, none of the existing treatments are considered entirely satisfactory or ideal in these cases. After extensive progressive research, oral small molecule therapies targeting mediators of ongoing inflammation represent an exciting and revolutionary change in the treatment of ulcerative colitis, especially for patients with moderate-to-severe disease. In this review, we aimed to summarize the available experience and ongoing research on oral small molecule agents in the management of ulcerative colitis. The available experience and ongoing research with promising outcomes provide convincing evidence that the value of oral small molecule agents is fact not fancy.

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

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

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

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

Cytokines and cytokine receptors as targets of immune-mediated inflammatory diseases-RA as a role model

Recent advances in our understanding in the immune-mediated inflammatory diseases (IMID) are explored and promoted by the targeted treatment. Among these targets, cytokines and cytokine receptors have become the good candidates for the drug development. In this review, the cytokine and cytokine receptors, which are approved in IMID, are overviewed, and modalities of the treatment, the role of cytokines and cytokine receptors in each disease, and the updated molecular information by modern technologies in rheumatoid arthritis as a role model are shown and discussed for the future perspectives.

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

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

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

Objective

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

Methods

This open-label, randomized study was conducted at one site in China. Subjects received peficitinib 50, 100 or 150 mg as a single dose on Day 1 (fasted) and once daily from Days 8 to 13 in the multiple-dose period (fed). Blood samples were collected before administration each day, and up to 72h post administration. Pharmacokinetic assessments included area under the concentration curve (AUC), half-life (t1/2), maximum concentration (Cmax), and time to maximum concentration (tmax) of peficitinib and its metabolites (H1, H2 and H4). Treatment-emergent adverse events (TEAEs) were evaluated.

Results

Thirty-six subjects were enrolled (12 per dose group). After a single dose of peficitinib, median tmax was 1.0-1.5h and mean t1/2 was 7.4-13.0h for all doses. In the multiple-dose period, median tmax was 1.5-2.0h. Dose-proportional increases in Cmax and AUC24h were observed for peficitinib and its metabolites following single and multiple doses, with minimal drug accumulation. The major metabolite was H2, with a systemic exposure of >150% of the parent AUC. Drug-related TEAEs were experienced by 5 (13.9%) and 12 (33.3%) subjects in the single- and multiple-dose periods, respectively. Following multiple doses of peficitinib, TEAEs were more frequent in higher than lower dose groups but were mild in severity with no related discontinuation or death.

Conclusion

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

Clinicaltrialsgov Identifier

NCT04143477.

A Comprehensive Overview of Globally Approved JAK Inhibitors

Janus kinase (JAK) is a family of cytoplasmic non-receptor tyrosine kinases that includes four members, namely JAK1, JAK2, JAK3, and TYK2. The JAKs transduce cytokine signaling through the JAK-STAT pathway, which regulates the transcription of several genes involved in inflammatory, immune, and cancer conditions. Targeting the JAK family kinases with small-molecule inhibitors has proved to be effective in the treatment of different types of diseases. In the current review, eleven of the JAK inhibitors that received approval for clinical use have been discussed. These drugs are abrocitinib, baricitinib, delgocitinib, fedratinib, filgotinib, oclacitinib, pacritinib, peficitinib, ruxolitinib, tofacitinib, and upadacitinib. The aim of the current review was to provide an integrated overview of the chemical and pharmacological data of the globally approved JAK inhibitors. The synthetic routes of the eleven drugs were described. In addition, their inhibitory activities against different kinases and their pharmacological uses have also been explained. Moreover, their crystal structures with different kinases were summarized, with a primary focus on their binding modes and interactions. The proposed metabolic pathways and metabolites of these drugs were also illustrated. To sum up, the data in the current review could help in the design of new JAK inhibitors with potential therapeutic benefits in inflammatory and autoimmune diseases.

Affecting the effectors: JAK inhibitors modulation of immune cell numbers and functions in patients with rheumatoid arthritis

INTRODUCTION

The Janus kinase family includes four members - JAK1, JAK2, JAK3, TYK2 that are selectively associated with type I and II cytokine receptors. Jak-inhibitors (Jakinibs) are a new class of drugs for treating inflammatory diseases. Five Jakinibs are currently available for Rheumatoid Arthritis (RA): tofacitinib, baricitinib, upadacitinib, filgotinib and peficitinib. Considering the role of cytokines and growth factors in immune cell survival and activation, the anti-proliferative and suppressive effects of Jakinibs on these cells are predictable.

AREAS COVERED

This review summarizes Jakinibs' effects of on immune populations in vitro and in vivo. In vitro, Jakinibs affected T and B lymphocytes, monocytes, neutrophils and dendritic cell proliferation. T helper, B cell differentiation and cytokine secretion was impaired. Accordingly, changes in the number of lymphocytes, natural killer (NK) cells and neutrophils have been reported during the randomized clinical trials with all the Jakinibs, reverting after drug withdrawal.

EXPERT OPINION

In vitro and in vivo studies showed that the numbers and the function of immune cells are influenced by Jakinibs. Nonetheless, their effects do not seem to represent a major safety issue as these changes do not correlate with the onset of serious infection despite the increased rates of herpes zoster reactivation.

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

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

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

OBJECTIVES

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

METHOD

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

RESULTS

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

CONCLUSIONS

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

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

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

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

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

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

Jakinibs of All Trades: Inhibiting Cytokine Signaling in Immune-Mediated Pathologies

Over the last 25 years, inhibition of Janus kinases (JAKs) has been pursued as a modality for treating various immune and inflammatory disorders. While the clinical development of JAK inhibitors (jakinibs) began with the investigation of their use in allogeneic transplantation, their widest successful application came in autoimmune and allergic diseases. Multiple molecules have now been approved for diseases ranging from rheumatoid and juvenile arthritis to ulcerative colitis, atopic dermatitis, graft-versus-host-disease (GVHD) and other inflammatory pathologies in 80 countries around the world. Moreover, two jakinibs have also shown surprising efficacy in the treatment of hospitalized coronavirus disease-19 (COVID-19) patients, indicating additional roles for jakinibs in infectious diseases, cytokine storms and other hyperinflammatory syndromes. Jakinibs, as a class of pharmaceutics, continue to expand in clinical applications and with the development of more selective JAK-targeting and organ-selective delivery. Importantly, jakinib safety and pharmacokinetics have been investigated alongside clinical development, further cementing the potential benefits and limits of jakinib use. This review covers jakinibs that are approved or are under late phase investigation, focusing on clinical applications, pharmacokinetic and safety profiles, and future opportunities and challenges.

Computer aided designing of novel pyrrolopyridine derivatives as JAK1 inhibitors

Janus kinases (JAKs) are a family of non-receptor kinases that play a key role in cytokine signaling and their aberrant activities are associated with the pathogenesis of various immune diseases. The JAK1 isoform plays an essential role in the types 1 and II interferon signaling and elicits signals from the interleukin-2, interleukin-4, gp130, and class 2 receptor families. It is ubiquitously expressed in humans and its overexpression has been linked with autoimmune diseases such as myeloproliferative neoplasm. Although JAK1 inhibitors such as Tofacitinib have been approved for medical use, the low potency and off-target effects of these inhibitors have limited their use and calls for the development of novel JAK1 inhibitors. In this study, we used computational methods on a series of pyrrolopyridine derivatives to design new JAK1 inhibitors. Molecular docking and molecular dynamics simulation methods were used to study the protein-inhibitor interactions. 3D-quantitative structure–activity relationship models were developed and were used to predict the activity of newly designed compounds. Free energy calculation methods were used to study the binding affinity of the inhibitors with JAK1. Of the designed compounds, seventeen of the compounds showed a higher binding energy value than the most active compound in the dataset and at least six of the compounds showed higher binding energy value than the pan JAK inhibitor Tofacitinib. The findings made in this study could be utilized for the further development of JAK1 inhibitors.

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

INTRODUCTION

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

AREAS COVERED

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

EXPERT OPINION

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

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

TRIAL REGISTRATION

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

Emerging protein kinase inhibitors for the treatment of rheumatoid arthritis

INTRODUCTION

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

AREAS COVERED

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

EXPERT OPINION

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

JAK Inhibitors: Prospects in Connective Tissue Diseases

The dysregulation of the JAK-STAT pathway is associated with various immune disorders. Four JAK inhibitors have been approved for rheumatoid arthritis (RA), and numerous JAK inhibitors are currently being tested in phase II and III trials for the treatment of various autoimmune inflammatory diseases. In this narrative review, we elucidate the involvement of the JAK-STAT signaling pathway in the pathogenesis of connective tissue diseases (CTDs). We also discuss the efficacy of the first- and second-generation JAK inhibitors (tofacitinib, baricitinib, ruxolitinib, peficitinib, filgotinib, upadacitinib, solcitinib, itacitinib, decernotinib, R333, and pf-06651600) for CTDs including RA, systemic lupus erythematosus, dermatomyositis, systemic sclerosis, Sjögren's syndrome, and vasculitis, based on laboratory and clinical research findings. JAK inhibitors have great potential for the treatment of various CTDs by reducing multiple cytokine production and suppressing inflammation, with the advantages of rapid onset in an oral formulation and decreased corticosteroid dependence and the associated adverse events, especially in refractory cases. We also highlight the safety of novel JAK inhibitors, which can cause opportunistic infections, especially viral infections. Being a very recent therapeutic option, information regarding the safety of JAK inhibitors during pregnancy and for pediatric use is limited. However, it is recommended that JAK inhibitors should be avoided in pregnant and breastfeeding women. More clinical data, especially on highly selective inhibitors, are required to judge the efficacy and safety of JAK inhibition in CTDs.

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

OBJECTIVE

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

PATIENTS AND METHODS

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

RESULTS

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

CONCLUSION

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

Small Molecule Drugs in Inflammatory Bowel Diseases

Inflammatory bowel diseases (IBDs), mainly represented by Crohn’s disease (CD) and Ulcerative Colitis (UC), are chronic disorders with an unclear pathogenesis. This incurable and iterative intestinal mucosal inflammation requires the life-long use of anti-inflammatory drugs to prevent flares or relapses, which are the major providers of complications, such as small bowel strictures and intestinal perforations. The introduction of tumor necrosis factor (TNF)-alpha inhibitors and other compounds, such as anti-IL12/23 and anti-alpha4/beta7 integrin monoclonal antibodies, has considerably improved the clinical management of IBDs. They are now the standard of care, being the first-line therapy in patients with aggressive disease and in patients with moderate to severe disease with an inadequate response to conventional therapy. However, for approximately one third of all patients, their efficacy remains insufficient by a lack or loss of response due to the formation of anti-drug antibodies or compliance difficulties with parenteral formulations. To address these issues, orally administered Small Molecules Drugs (SMDs) that use a broad range of novel pharmacological pathways, such as JAK inhibitors, sphingosine-1-phosphate receptor modulators, and phosphodiesterase 4 inhibitors, have been developed for CD and UC. This article provides an updated and complete review of the most recently authorized SMDs and SMDs in phase II/III development.

Current jakinibs for the treatment of rheumatoid arthritis: a systematic review

OBJECTIVE

One-third of patients with severe rheumatoid arthritis (RA) do not achieve remission or low disease activity, or they have side effects from cDMARD and bDMARD. They will need a new treatment option such as the small molecule JAK inhibitors. In this systematic review, we evaluate the efficacy and safety data of the current jakinibs: tofacitinib, peficitinib, decernotinib, upadacitinib, baricitinib and filgotinib in patients in whom treatment with conventional or biological disease-modifying antirheumatic drugs (cDMARD and/or bDMARD) failed.

METHODS

We searched for randomized controlled trials comparing efficacy and safety of jakinibs for RA treatment using the Web of Science, Scopus, PubMed, and clinicaltrials.gov databases with the terms: "rheumatoid arthritis" OR "arthritis rheumatoid" OR "RA" AND "inhibitor" OR "jak inhibitor" AND "clinical trial" OR "treatment" OR "therapy".

RESULTS

All jakinibs achieved good results in ACR 20, 50, 70 and with CRP-DAS28 for LDA and remission, upadacitinib showed better results compared to the others. In ESR-DAS28 for remission, tofacitinib achieved the best result. Regarding the safety of all jakinibs, peficitinib, baricitinib and filgotinib did not register deaths in their studies unlike tofacitinib that presented 11 deaths. Despite all benefits of jakinibs, the use in patients with severe liver and kidney disease should be avoided.

CONCLUSIONS

Jakinibs in monotherapy or in combination with methotrexate can be considered a viable alternative in the treatment of moderate-to-severe RA. Even after failures with combination of cDMARDS and bDMARDS, jakinibs demonstrated efficacy.

Efficacy and safety of jakinibs in rheumatoid arthritis: a systematic review and meta-analysis

OBJECTIVES

To assess the efficacy and safety of jakinibs for the treatment of active rheumatoid arthritis (RA) in patients with an inadequate response or intolerance to conventional synthetic or biologic disease-modifying antirheumatic drugs (DMARDs).

METHODS

A systematic search was conducted in PubMed, Embase, and the Cochrane Library. Randomized placebo-controlled trials (RCTs) of jakinibs in RA patients were eligible. The effective outcome was RA improvement to reach an American College of Rheumatology 20%/50%/70% (ACR20/50/70) response rate at weeks 12 and 24 after treatment. The safety outcomes included treatment-emergent adverse events (TEAEs), serious adverse events (SAEs), and discontinuations due to adverse events, infections, and serious infections.

RESULTS

Twenty-eight randomized, double-blind, controlled trials including 14,500 patients were included. At both weeks 12 and 24, the pooled analysis suggested effective treatment with jakinibs, represented as an increased clinical response of ACR20, ACR50, and ACR70. Subgroup analysis based on different types of jakinibs demonstrated that only peficitinib treatment had no impact on the clinical response of ACR50 or ACR70 at week 12. Jakinibs were associated with an increased incidence of infections at week 12 and TEAEs and infections at week 24. No increase in the risk of SAEs, discontinuations due to adverse events, or serious infections was observed in comparisons between treatment with jakinibs and treatment with placebo in these patients.

CONCLUSIONS

Jakinibs are efficacious and well tolerated in RA patients up to 24 weeks, although they are associated with an increased risk of infectious complications. Key Points • ACR20/50/70 in patients treated with jakinibs was significantly higher than those in patients treated with placebo. • No difference in ACR50/70 was observed in patients with RA treated with peficitinib and placebo. • Jakinibs are beneficial and well tolerated in RA treatment.

JAK1 inhibition and inflammatory bowel disease

Primary non-response and secondary loss of response remain a significant issue with the currently available treatment options for a significant proportion of patients with inflammatory bowel disease (IBD). There are multiple unmet needs in the IBD treatment algorithm and new treatment options are required. As our understanding of the pathogenesis of IBD evolves, new therapeutic targets are being identified. The JAK-STAT pathway has been extensively studied. Tofacitinib, a JAK1 inhibitor, is now licensed for use in the induction and maintenance of ulcerative colitis and there are a large number of molecules currently under investigation. These new small molecule drugs (SMDs) will challenge current treatment pathways at a time when clinical therapeutic outcomes are rapidly evolving and becoming more ambitious. This is a review of the current JAK1 inhibitors in IBD including the current evidence from clinical trials.

Exposure-response modeling of peficitinib efficacy in patients with rheumatoid arthritis

The aim was to analyze the relationship between peficitinib exposure and efficacy response according to American College of Rheumatology (ACR) 20 criteria and 28‐joint disease activity score based on C‐reactive protein (DAS28‐CRP) in rheumatoid arthritis (RA) patients, and to identify relevant covariates by developing exposure–response models. The analysis incorporated results from three multicenter, placebo‐controlled, double‐blind studies. As an exposure parameter, individual post hoc pharmacokinetic (PK) parameters were obtained from a previously constructed population PK model. Longitudinal ACR20 response rate and individual longitudinal DAS28‐CRP measurements were modeled by a non‐linear mixed effect model. Influential covariates were explored, and their effects on efficacy were quantitatively assessed and compared. The exposure–response models of effect of peficitinib on duration‐dependent increase in ACR20 response rate and decrease in DAS28‐CRP were adequately described by a continuous time Markov model and an indirect response model, respectively, with a sigmoidal E_max saturable of drug exposure in RA patients. The significant covariates were DAS28‐CRP and total bilirubin at baseline for the ACR20 response model, and CRP at baseline and concomitant methotrexate treatment for the DAS28–CRP model. The covariate effects were highly consistent between the two models. Our exposure–response models of peficitinib in RA patients satisfactorily described duration‐dependent improvements in ACR20 response rates and DAS28‐CRP measurements, and provided consistent covariate effects. Only the ACR20 model incorporated a patient's subjective high expectations just after the start of the treatment. Therefore, due to their similarities and differences, both models may have relevant applications in the development of RA treatment.

Clinical trial registration

NCT01649999 (RAJ1), NCT02308163 (RAJ3), NCT02305849 (RAJ4).

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.

Placebo and nocebo responses in randomized controlled trials of Janus kinase inhibitor monotherapy for rheumatoid arthritis : A meta-analysis

OBJECTIVE

The goal of this meta-analysis was to assess the frequency and magnitude of placebo and nocebo responses in placebo-controlled randomized controlled trials (RCTs) of Janus kinase (JAK) inhibitor monotherapy for rheumatoid arthritis (RA) METHODS: We performed a meta-analysis on the rates of placebo response, adverse effects (AEs), severe AEs (SAEs) and withdrawal due to AEs in placebo-controlled randomized clinical trials (RCTs) of JAK inhibitor therapy for RA.

RESULTS

Five RCTs contained a total of 1422 patients (746 trial participants and 676 controls). The pooled incidence of an American College of Rheumatology 20% (ACR20) response rate was 33.0% (95% CI 19.6-44.9%) in placebo-treated patients and 68.3% (95% CI 61.4-74.1%) in active drug-treated patients. A strong negative correlation was observed between drug efficacies (ACR20 response) and AE rates in the placebo arm, indicating that the stronger the placebo response, the weaker the nocebo response (r = -0.906, P = 0.034). The pooled estimate of at least one AE was 54.1% (95% CI 44.6-63.4%) in placebo-treated patients and 54.5% (95% CI 46.2-62.6%) in active drug-treated patients. The pooled SAE rate was 3.9% (95% CI 2.7-5.7%) in placebo-treated patients and 3.8% (95% CI 2.5-5.7%) in active comparator-treated patients. The pooled estimate of withdrawal owing to an AE was 4.1% (95% CI 1.4-11.3%) in placebo-treated patients and 2.1% (95% CI 0.8-5.4%) in active drug-treated patients. However, there were no differences in the pooled risk of AE, SAEs, or withdrawal owing to AEs between the active comparator and placebo groups. A strong positive correlation was observed in AE rates between the placebo and active arms, indicating that the stronger the nocebo response, the higher the AE rate in the active arm (r = 0.957, P = 0.012).

CONCLUSION

The frequency of placebo and nocebo responses was 33.0 and 54.1%, respectively, in JAK monotherapy trials for RA. The findings indicated that the strengths of placebo and nocebo responses are inversely proportional and that clinically significant differences were absent between AE, SAE, and dropout owing to AEs.

Safety and Effectiveness of Peficitinib (ASP015K) in Patients with Rheumatoid Arthritis: Final Results (32 Months of Mean Peficitinib Treatment) From a Long-Term, Open-Label Extension Study in Japan, Korea, and Taiwan

INTRODUCTION

This final analysis of a long-term extension (LTE) study assessed the safety, tolerability, and effectiveness of peficitinib (ASP015K), a pan-Janus kinase inhibitor, in Asian patients with rheumatoid arthritis (RA).

METHODS

Patients had previously completed the 12-week phase 2b (RAJ1), or 52-week phase 3 (RAJ3 and RAJ4) peficitinib studies in Japan, Korea, and Taiwan, and received oral peficitinib 50 or 100 mg/day. Dose increase to 150 mg/day or reduction to 50 mg/day was permitted. Efficacy endpoints included American College of Rheumatology (ACR)20/50/70 response rates, 28-joint Disease Activity Score with C-reactive protein (DAS28-CRP), and ACR components. Safety endpoints included treatment-emergent adverse events (TEAEs), and incidence rates (IRs) of adverse events of special interest per 100 patient-years (PY).

RESULTS

Overall, 843 patients received peficitinib for a mean 32.0 months (maximum 85.2 months), and most (64.4%) received peficitinib 100 mg/day as a maximum dose. Respective ACR20/50/70 response rates were maintained from baseline (week 0 of LTE; 71.6, 52.1, and 34.7%) to end of treatment (78.7, 63.3, and 44.1%); continuous improvements in ACR components and DAS28-CRP were observed from the baselines of preceding studies and throughout the LTE. Overall, 796/843 (94.4%) patients experienced TEAEs; most were severity grade 1/2. Most common TEAEs were nasopharyngitis (47.0%) and herpes zoster (17.3%). Drug-related TEAEs leading to permanent discontinuation occurred in 140 (16.6%) patients, and IRs (95% confidence interval) per 100 PY of serious infections, herpes zoster-related disease, and malignancies were 2.7 (2.1, 3.4), 7.3 (6.2, 8.6), and 1.2 (0.9, 1.8), respectively. Two deaths occurred during the study; one each from diffuse large B cell lymphoma and pneumonia, which were, respectively considered probably and possibly related to study drug.

CONCLUSIONS

Improvements in effectiveness variables were maintained during this long-term study of peficitinib in Asian patients with RA; peficitinib was generally well tolerated over a mean 32 months' duration.

TRIAL REGISTRATION

ClinicalTrials.gov. NCT01638013, retrospectively registered on 11 July 2012 https://clinicaltrials.gov/ct2/show/NCT01638013 .

Drug-Drug Interactions at Organic Cation Transporter 1

The interaction between drugs and various transporters is one of the decisive factors that affect the pharmacokinetics and pharmacodynamics of drugs. The organic cation transporter 1 (OCT1) is a member of the Solute Carrier 22A (SLC22A) family that plays a vital role in the membrane transport of organic cations including endogenous substances and xenobiotics. This article mainly discusses the drug-drug interactions (DDIs) mediated by OCT1 and their clinical significance.

Interpretation of network meta-analyses of the efficacy of rheumatoid arthritis drugs

WHAT IS KNOWN AND OBJECTIVE

Both biological agents and Janus kinase (JAK) inhibitors have been shown to be effective in rheumatoid arthritis (RA) patients with inadequate responses to tumour necrosis factor (TNF) inhibitors. Network meta-analyses are useful for comparing drug effectiveness in the absence of direct head-to-head comparisons. We comment on two such meta-analyses reported in this Journal to highlight aspects of their interpretation.

COMMENT

In network meta-analyses, it is important to critically examine whether the direct and indirect estimates are divergent, keeping in mind that the surface under the cumulative ranking probability curve (SUCRA) is a relative value in such analyses. In two studies, examining the effect of therapeutic agents for RA by using NMA, the SUCRA method, produced a distinct ranking for JAK inhibitors in monotherapy, and non-TNF inhibitors and JAK inhibitors, in cases of TNF failure. Nonetheless, the differences in treatment effects were small and their clinical significance requires validation.

WHAT IS NEW AND CONCLUSION

NMA is a useful method for studying the comparative effectiveness of multiple treatments. However, increased attention should be paid when using this method to distinguish statistically significant differences from clinically meaningful differences.

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

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

Population pharmacokinetic analysis of peficitinib in patients with rheumatoid arthritis

Aims

To analyse the population pharmacokinetics (PK) of peficitinib in patients with rheumatoid arthritis (RA) and assess the potential PK covariates to identify the requirement for dose adjustment in RA patients.

Methods

The analysis incorporated 2464 observations from 98 healthy volunteers and 4919 observations from 989 RA patients. A population PK model for peficitinib in RA patients was constructed by a nonlinear mixed effect model using NONMEM with prior information from a healthy volunteer model.

Results

A 2‐compartment model with sequential zero‐ and first‐order absorption and lag time was constructed for RA patients. Covariate exploration in the RA patient model revealed that estimated glomerular filtration rate (eGFR) and lymphocyte count had a significant effect on apparent total systemic clearance (CL), which was 91.7 L/h (2.3% relative standard error). Compared with the mean population CL, the model predicted mean changes in CL of 12.3 and −10.7% in patients with observed minimum and maximum lymphocyte count of 500 and 4600 10⁶/L, respectively, and mean changes in CL of −17.8 and 16.7% in patients with minimum and maximum eGFR of 36.4 and 188 mL/min/1.73m², respectively. The simulated population mean area under plasma concentration–time curve for 24 hours after dosing showed a 1.35‐fold increase in patients with severe renal impairment (eGFR 22.5 mL/min/1.73m²) compared with patients with reference eGFR (91.5 mL/min/1.73m²).

Conclusion

The population PK model identified eGFR and lymphocyte count as covariates for CL. The magnitude of changes was not considered clinically relevant, indicating no requirement for dose adjustment.

A pooled safety analysis of peficitinib (ASP015K) in Asian patients with rheumatoid arthritis treated over a median of 2 years

OBJECTIVE

To evaluate the safety of peficitinib for the treatment of rheumatoid arthritis (RA) in Asian patients.

METHODS

Safety data from one Phase 2b, two Phase 3, and one open-label long-term extension study [data cut-off 31 May 2018] were pooled into Phase 3 studies (peficitinib 100 and 150 mg/day, and placebo) and Phase 2/3 studies (all peficitinib-treated patients). Incidence rates per 100 patient-years (PY) of adverse events (AEs) of special interest were calculated.

RESULTS

Overall, 1052 patients received peficitinib for 2336.3 PY of exposure (median 2.1 years); four deaths occurred, including one death after the studies. AE incidence was similar across peficitinib 100 and 150 mg/day groups (Phase 3 studies). Respective peficitinib and placebo incidence rates (95% confidence interval) per 100 PY were 2.9 (1.9, 4.6) and 0.0 for serious infections, 5.7 (4.2, 7.9) and 2.3 (0.6, 9.4) for herpes zoster-related disease, and 0.6 (0.2, 1.6) and 1.2 (0.2, 8.3) for malignancies (excluding non-melanoma skin cancer) (Phase 3 studies), and 0.1 (0.0, 0.3) for venous thromboembolism in all peficitinib-treated patients (Phase 2/3 studies).

CONCLUSION

Peficitinib was well tolerated in Asian patients with RA over a median of 2 years, with no observed dose or temporal dependency for AEs with prolonged administration.

Points to consider for the treatment of immune-mediated inflammatory diseases with Janus kinase inhibitors: a systematic literature research

OBJECTIVES

Review of efficacy and safety of Janus kinase (JAK) inhibition in immune-mediated inflammatory diseases (IMIDs).

METHODS

A systematic literature research (SLR) of all publications on JAK inhibitors (JAKi) treatment published until March 2019 using MEDLINE, EMBASE and the Cochrane Library. Efficacy and safety were assessed in randomised controlled trials (RCTs), integrating long-term extension periods additionally for safety evaluation.

RESULTS

3454 abstracts were screened with 85 included in the final analysis (efficacy and RCT safety: n=72; safety only: n=13). Efficacy of RCTs investigating tofacitinib (TOFA, n=27), baricitinib (BARI, n=9), upadacitinib (UPA, n=14), filgotinib (FILGO, n=7), decernotinib (DEC, n=3) and peficitinib (PEF, n=7) was evaluated. Six head-to-head trials comparing JAKi with tumour necrosis factor inhibitors (TNFi) were included. Efficacy of JAKi was shown in rheumatoid arthritis (RA) for all agents, psoriatic arthritis (TOFA, FILGO), ankylosing spondylitis (TOFA, FILGO), systemic lupus erythematosus (BARI), chronic plaque psoriasis (TOFA, BARI, PEF), ulcerative colitis (TOFA, UPA), Crohn's disease (UPA, FILGO) and atopic dermatitis (TOFA, BARI, UPA). Safety analysis of 72 RCTs, one cohort study and 12 articles on long-term extension studies showed increased risks for infections, especially herpes zoster, serious infections and numerically higher rates of venous thromboembolic events. No increased malignancy rates or major adverse cardiac events were observed.

CONCLUSION

JAKi provide good efficacy compared to placebo (and to TNFi in RA and Pso) across various IMIDs with an acceptable safety profile. This SLR informed the task force on points to consider for the treatment of IMIDs with JAKi with the available evidence.

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.

State of the art: approved and emerging JAK inhibitors for rheumatoid arthritis

INTRODUCTION

Rheumatoid arthritis (RA) is the most common autoimmune inflammatory arthritis in adults. In the past decade, many treatments have emerged to expand the therapeutic armamentarium of rheumatologists. Among emerging treatments, Janus Kinase inhibitors (JAKi) are promising in treating RA and several other inflammatory conditions, such as psoriatic arthritis (PsA). The JAK/STAT signaling pathway is located downstream certain cytokines receptors that are known to be involved in RA pathogenesis. So far, three JAKi are approved for the treatment of RA, while other JAKi, are under investigation.

AREAS COVERED

Herein, the authors review those JAKi approved and emerging for the treatment of RA and provide their expert perspectives on the subject area.

EXPERT OPINION

JAKi represent an interesting alternative to other DMARDs when MTX has failed. Long-term extension studies are still ongoing, but one can assume that most of the major safety concerns have already come out. Switching from one JAKi to another DMARD has been little studied, but in such cases, preferring a treatment which does not interfere with the JAK/STAT pathway seems to be a reasonable choice.

JAK Inhibitors in Rheumatoid Arthritis: An Evidence-Based Review on the Emerging Clinical Data

Janus kinase (JAK) Inhibitors are the latest drug class of disease-modifying medication to emerge for the treatment of rheumatoid arthritis (RA). They are a small molecule-targeted treatment and are the first oral option to compare favourably to existing biologic disease-modifying anti-rheumatic drugs (DMARDs). Tofacitinib, baricitinib and upadacitinib are the first 3 JAK inhibitors to become commercially available in the field and are the core focus of this review. To date, they have demonstrated comparable efficacy to tumour necrosis factor (TNF) inhibitors in terms of American College of Rheumatology (ACR) response rates and disease activity (DAS28) scores with similar cost to the benchmark adalimumab. This narrative review article aims to synthesise and distil the key available trial data on JAK inhibitor efficacy and safety, along with their place in the ACR and European League Against Rheumatism (EULAR) guidelines for RA. The novel mechanism of action of the JAK/STAT pathway is highlighted along with the potential effects of modulating each pathway. The rapid onset of action, role in attenuation of central pain processing and effect on structural damage and radiographic progression are also all examined in detail. We also explore the latest meta-analyses and comparative performance of each of the 3 available JAKs in an effort to determine which is most efficacious and which has the most favourable safety profile. Post marketing concerns regarding thromboembolism risk and herpes zoster infection are also discussed. Additionally, we review the cost-benefit analyses of the available JAK inhibitors and address some of the pharmacoeconomic considerations for real-world practice in the UK and US by detailing the raw acquisition cost and the value they provide in comparison to the benchmark biologic adalimumab and the anchor DMARD methotrexate.

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.