October 2020

Preclinical characterisation of itacitinib, a Novel Selective Inhibitor of JAK1, for the Treatment of Inflammatory Diseases

European Journal of Pharmacology. 2020 Oct 15;885:173505. doi: 10.1016/j.ejphar.2020.173505

Itacitinib is an orally active JAK inhibitor and effectively delayed disease onset, reduced symptom severity, and accelerated recovery of inflammatory diseases in mouse models. Covington M et al demonstrated itacitinib’s high selectivity for JAK 1, its inhibition on IL-2 induced T cell proliferation and JAK/STAT signalling, its ability to also inhibit of the JAK/STAT pathway in response to IL-6 stimulation, and its effect on rat adjuvant induced arthritis model. The study used recombinant enzym...

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September 2019

Comparison of Baricitinib, Upadacitinib, and Tofacitinib Mediated Regulation of Cytokine Signalling in Human Leukocyte Subpopulations

Arthritis Res Ther. 2019 Aug 2;21(1):183

Different JAKinibs modulated distinct cytokine pathways to varying degrees, and no agent potently or continuously inhibited an individual cytokine signalling pathway throughout the dosing interval. This study aimed to compare the in vitro cellular pharmacology of BARI, TOF and UPA across relevant leukocyte subpopulations, coupled with their in vivo PK, to determine their effects on distinct cytokine pathways. Peripheral blood mononuclear cells from healthy donors were incubated with different JA...

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July 2016

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

Ann Rheum Dis. 2016 Jun;75:1057-64. doi: 10.1136/annrheumdis-2015-208279. Epub 2015 Dec 15

Peficitinib (ASP015K) is a novel orally bioavailable JAK inhibitor in development for the treatment of RA. It inhibits JAK1, JAK2, JAK3 and Tyk2 enzyme activities and has moderate selectivity or JAK3 inhibition.Here the authors report the findings of a 12-week, randomized, double-blind, placebo-controlled phase IIb study evaluating efficacy, safety and dose response of peficitinib (25, 50, 100, or 150 mg) as once-daily oral monotherapy in Japanese patients with moderate to severe RA. The primar...

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June 2014

Structure of the pseudokinase-kinase domains from protein kinase TYK2 reveals a mechanism for Janus kinase (JAK) autoinhibition

Proc Natl Acad Sci U S A. 2014 May 19. pii: 201401180. [Epub ahead of print]

The JAK family of kinases (JAK1, JAK2, JAK3 and TYK2) are receptor-associated tyrosine kinases that act downstream of many cytokines and interferons. Recent studies have provided structural information about the kinase and pseudokinase domains of JAKs however the molecular mechanism by which JAK activity is regulated by the pseudokinase domain is poorly understood. This study builds on a recent finding that the N terminus of the JAK1 pseudokinase group may act as a switch for kinase activation b...

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Structural basis for the recognition of interferon-α receptor by tyrosine kinase 2

Nat Struct Mol Biol. 2014 May;21(5):443-8. doi: 10.1038/nsmb.2807. Epub 2014 Apr 6

Janus kinases, JAKs, are essential in the mediation of cytokine and interferon signalling whilst also being crucial to body processes such as immune function, hematopoeises, metabolism and cellular growth. However, it is not known is how the four members of the JAK family interact with and are activated by over 30 cytokine receptors with near perfect affinity and specificity. Currently, there are no crystal structures available for any JAK bound to a cytokine receptor. This study sought address ...

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April 2014

Molecular pathways: Molecular basis for sensitivity and resistance to JAK inhibitors

Clin Cancer Research doi:10.1158/1078-0432.CCR-13-0279

Janus kinases (JAKs) mediate the regulation of a variety of cytokine signals with alterations in JAK1, JAK2, JAK3 and Tyk2 signalling contributing to many disease states including autoimmune diseases and haematological malignancies. Recently tofacitinib and ruxolitinib have been approved for treatment for rheumatoid arthritis and myelofibrosis respectively. Several JAK2 inhibitors, such as momelotinib and pacritinib, currently in development for myelofibrosis and the JAK1/2 inhibitor baricitinib...

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