June 2013

Cytokine receptor signaling through the Jak–Stat–Socs pathway in disease

Molecular Immunology 2007; 44:2497-506

This review from 2007 provides an overview of the largest cytokine receptor family, the haematopoietin receptors, as well as other key components involved in one of the major cytokine signalling pathways implicated in autoimmune and inflammatory diseases. This includes the Janus kinases (Jaks), signal transducers and activators of transcription (Stats) and suppressors of cytokine signalling genes (Socs). Essentially, when a cytokine binds to a receptor from this group a functional cytokine recep...

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Janus kinases in immune cell signaling

Immunological Reviews 2009; 228:273-87

This review from 2009 describes the Janus Kinases (JAK) that includes JAK1, JAK2, and JAK3, a subgroup of non-receptor protein tyrosine kinases. This protein family has a diverse range of functions including roles in cell growth, survival, development, and differentiation of a variety of cells, and especially immune and haematopoietic cells. Current knowledge of protein structure, regulatory mechanisms, signalling pathways and intracellular interactions for the JAK family is reviewed. The paper ...

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Inhibition of JAK kinases in patients with rheumatoid arthritis: scientific rationale and clinical outcomes

Best Practice & Research Clinical Rheumatology 2010; 24:513-26

This article reviews data from animal and phase 2 clinical studies assessing the immunomodulatory effects and pharmacokinetics of CP-690,550 (now known as tofacitinib), as well as its efficacy and safety in patients with rheumatoid arthritis (RA). In two rodent models of arthritis, CP-690,550 produced dose-dependent decreases in signs of disease activity compared with untreated controls, reductions in histologically assessed inflammation and articular cartilage damage, and statistically signific...

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Small molecules targeting JAKs—a new approach in the treatment of rheumatoid arthritis

Rheumatology 2013: doi: 10.1093/rheumatology/kes417

This article focuses on the development of new small molecular inhibitors of Janus kinases (Jaks) in clinical trials for rheumatoid arthritis (RA). Of these, tofacitinib is at the most advanced stage of its clinical development and this article includes an overview of the results from the main tofacitinib clinical trials to date. These include the ORAL-Start study in methotrexate (MTX)-naïve patients; ORAL-Scan in inadequate responders to MTX; ORAL-Solo and ORAL-Sync in inadequate responders to ...

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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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Selective inhibition of JAK1 and JAK2 is efficacious in rodent models of arthritis: preclinical characterization of INCB028050

Journal of Immunology 2010; 184(9):5298-307

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...

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Modulation of innate and adaptive immune responses by tofacitinib (CP-690,550)

Journal of Immunology 2011; 186(7):4234-43

This study investigated the effects of the novel Janus kinase (JAK) inhibitor CP-690,550 (now known as tofacitinib) on adaptive and innate immune responses, in order to establish the mode of action of JAK inhibitors in the setting of inflammatory diseases. The inhibition of specific JAK/STAT-dependent pathways by CP-690,550 was determined through analysis of cytokine stimulation of mouse and human T cells in vitro.The effects of CP-690,550 on Th-cell differentiation of naive murine CD4+...

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The JAK inhibitor CP-690,550 (tofacitinib) inhibits TNF-induced chemokine expression in fibroblast-like synoviocytes: autocrine role of type 1 interferon

Annals of Rheumatic Diseases 2012; 71:440-47

This study investigated the effect of the novel Janus kinase (JAK) inhibitor CP-690,550 [tofacitinib] in fibroblast-like synoviocytes (FLSs) collected from patients with rheumatoid arthritis (RA). Human FLSs were cultured from the synovial tissue of patients with RA who were undergoing arthroplastic surgery, cultured and then serum-starved 48 hours prior to stimulation. Quantitative polymerase chain reaction (PCR) and enzyme-linked immunosorbent assay (ELISA) or multiplex bead assay were used to...

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A phase IIb dose-ranging study of the oral JAK inhibitor tofacitinib (CP-690,550) versus placebo in combination with background methotrexate in patients with active rheumatoid arthritis and an inadequate response to methotrexate alone

Arthritis & Rheumatism 2012; 64(4):970-81

This study was one of two 24-week, phase 2b studies undertaken to characterise the efficacy and safety dose-response profile of the oral Janus kinase (JAK) inhibitor tofacitinib. Six doses of tofacitinib (20 mg daily and 1, 3, 5, 10 and 15 mg twice daily) and placebo were compared as add-on therapy in adults with active RA despite methotrexate (MTX) therapy. At week 12, ACR 20 response rates were significantly higher with all tofacitinib doses than with placebo (tofacitinib 45.7–58.1%; 33% place...

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Placebo-controlled trial of tofacitinib monotherapy in rheumatoid arthritis

The New England Journal of Medicine 2012; 367(6):495-507

This is the first phase 3 study to be published for the oral Janus kinase (JAK) inhibitor tofacitinib. This study investigated tofacitinib as a monotherapy in adults with active rheumatoid arthritis who previously failed to respond to disease modifying anti-rheumatic drugs (DMARDs). The study demonstrated that tofacitinib, compared to placebo, was more likely to be associated with reductions in the signs and symptoms of rheumatoid arthritis and improvement in physical function. 59.8% of patients...

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