The role of p38-MAPK inhibitors in treating RA is the subject of some debate. Li et al. therefore performed the first meta-analysis of the current data to evaluate the efficacy and safety of these compounds. The authors identified 3 papers, covering 4 RCTs, for analysis and the results showed that p38-MAPK inhibition achieves a better level of ACR20 improvement vs. placebo, but showed no meaningful difference in ACR50, DAS28 or CRP levels past week 12. Due to the inadequate number and quality of...

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Ibrutinib and novel BTK inhibitors in clinical development

Journal of Hematology & Oncology 2013;6:59

Bruton’s tyrosine kinase (BTK) is a part of the cytokine signalling pathways involved in malignancies and autoimmune disorders.. Akinleye et al. provide a review of all the current BTK inhibitors in preclinical and clinical trials for B-cell malignancies and autoimmune disorders, including rheumatoid arthritis. Particular focus is placed on ibrutinib, a novel human BTK-inhibitor, currently in phase III clinical trials. The authors also discuss four new compounds with potential indications in rh...

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Current JAK inhibitors CP-690,550 and INCB020850 have inhibitory effects on multiple JAK pathways, therefore Migita et al. tested whether selective inhibition of JAK3, using PF-956980, would be enough to ameliorate the rheumatoid inflammatory process. The results indicated that the inhibition of JAK3 alone is does not achieve control of STAT3-dependent signalling, and while it is suggested that the targeting of singular JAK pathways should lead to fewer adverse events, it appears that this appro...

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Many patients with active RA have an inadequate response to biologic and nonbiologic DMARDs. Kremer et al carried out a one year, randomized trial studying the efficacy of tofacitinib in conjunction with background nonbiologic DMARDs (primarily methotrexate) in these patients. The results showed that using tofacitinib in combination with nonbiologic DMARDs rapidly improved physical function and reduced signs and symptoms of RA versus placebo, measured by ACR20 rates, DAS28 and HAQ-DI. The data f...

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September 2013

SYK plays a significant role in the immune cell signalling of B cells, mast cells, macrophages and neutrophils. Kaur et al. provide a comprehensive review of the molecule, its role in autoimmune disease and clinical data on its inhibition. The paper covers the basic chemistry of SYK including structure, mechanism of action, synthetic derivatives and function, and the relevance of SYK as a therapeutic target for many autoimmune diseases is discussed. The SYK inhibitors currently in clinical trial...

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Chakravaty et al. provide a comprehensive review of the scientific basis for kinase inhibitor use, and summarise experience from clinical trials in tofacitinib and fostamatinib, plus promising clinical data for p38-MAPK inhibitors and P13K? and P13Kd. The authors highlight potential future directions and challenges in kinase inhibitor research, including the emergence of kinases upstream of p38, such as MKK-3 and MKK-6, and the potential of BTK inhibition. One of the challenges of kinase inhibit...

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August 2013

The JAK inhibitor tofacitinib for active rheumatoid arthritis: results from phase III trials

International Journal of Clinical Rheumatology June 2013; 8(3):311–13

The tofacitinib ORAL research program involves six phase 3 trials (Standard, Solo, Step, Scan, Sync and Start) to assess the safety and efficacy of tofacitinib 5 and 10 mg twice daily as monotherapy, or with either background MTX or traditional DMARD therapy. This report by Salgado et al. provides an overall analysis of the each of the study designs and the clinical results to date. The results show that tofacitinib effectively controlled the signs and symptoms of RA across a range of patient po...

June 2013

Janus kinases inhibitors in autoimmune diseases

Annals of the Rheumatic Diseases 2013; 72:ii111-ii115

This review describes the role of various cytokines in rheumatoid arthritis (RA) and related diseases. This includes an overview of the different types of cytokine receptors including type I, which bind some of the interleukins (ILs), colony stimulating factors (CSFs) and hormones such as erythropoietin, prolactin and growth hormone (GH); and type II, which bind to interferons and IL-10-related proteins. In addition, the cytoplasmic domain of type I and II cytokine receptors bind to members of a...

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This study investigated the capacity of the novel oral spleen tyrosine kinase (Syk) inhibitor R406, and its prodrug R788 (fostamatinib), to suppress the reversed passive Arthrus reaction (RPA) and collagen-induced arthritis (CIA) in rats. R406 (0.1, 1, 5 and 10 mg/kg) and R788 (10 and 30 mg/kg) reduced the cutaneous RPA reaction and inflammatory oedema in a dose-dependent manner, with statistically significant reductions in extravascular leakage and tissue swelling (72% reduction with R406 10 mg...
This preclinical characterisation study examined the efficacy and tolerability of the small molecule INCB028050 (now known as baricitinib), an orally bioavailable, selective Janus kinase (JAK) 1/JAK2 inhibitor, in rodent models of arthritis. The decision to investigate its effects of INCB028050 followed positive evidence for the related compound ruxolitinib, the JAK inhibitor tofacitinib and the IL-6 inhibitor tocilizumab in rheumatoid arthritis (RA). In this preclinical study, INCB028050 was sh...