Differential Properties of Janus Kinase Inhibitors in the Treatment of Immune-mediated Inflammatory Diseases

Rheumatology (Oxford) 2023;63(2):298–308 doi 10.1093/rheumatology/kead448

JAKis differ in structure, which affects their inhibitory concentration for different JAKs.

This review by Taylor, et al. compares the pharmacological profiles of JAKis, including abrocitinib, baricitinib, filgotinib, peficitinib, tofacitinib, and upadacitinib.

November 2019

Absolute serious infection rates were low. However, across the JAKinibs, the incidence of HZ is higher than expected for the population. While the risk was numerically greatest with BARI, indirect comparisons between the drugs did not demonstrate any significant difference in risk. How JAKinibs increase the risk of HZ reactivation is unclear, but how different JAKs interact in the immune response suggest that there may be differences in safety profiles between JAKinib drugs, underpinned by their...

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May 2019

How JAKinibs increase the risk of HZ reactivation is unclear. Roles of different JAKs in the immune response may suggest differences in safety profiles between drugs, underpinned by their differential JAK selectivity profiles. The authors undertook a systematic review and meta-analysis to evaluate SI and opportunistic indicator infections including HZ in RA Phase II/III clinic trials with JAKinibs. A literature review of RCT of TOF (5 mg BID), BARI (4 mg OD) and UPA (15 mg OD) was conducted. A p...

December 2017

JAK Inhibition as a Therapeutic Strategy for Immune and Inflammatory Diseases

Nat Rev Drug Discov 2017;16:843–62 DOI: 10.1038/nrd.2017.201

Janus kinases (JAKs) are essential mediators of downstream signaling pathways in many inflammatory and autoimmune diseases. This review summarizes current clinical data on first- and second-generation JAK inhibitors (jakinibs) and discusses their use for the treatment of immune and inflammatory conditions.First generation jakinibs such as tofacitinib, baricitinib, and ruxolitinib, non-selectively inhibit JAK-dependent pro-inflammatory cytokines, which are major contributors to immunopathology. T...

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April 2017

This review discusses the current understanding of the safety of JAK inhibitors, including providing an overview of the changes in laboratory parameters, infection and malignancy risks associated with each JAK inhibitor compound.The review discusses the adverse event profiles and cellular changes characteristically seen with each JAK inhibitor, as well as the overlap or differences between the various compounds. The relative specificities for different JAKs between each compound do not always p...

December 2014

Non-response, parenteral administration and cost to produce are all aspects associated with the currently available anti-cytokine agents for RA. These related factors mean that alternative drugs are now being developed. Recent developments in therapeutic drugs to treat RA have focused on Janus kinases (JAKs) and signal transducer and activator of transcription (STATs) transcription pathways. Several cytokines that regulate immune responses in RA, such as IFN-g, IL-6 and IL-10, activate JAK-STAT ...

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June 2014

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...

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 ...

April 2014

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...

October 2013

The role of JAKs is highly important in lymphocyte differentiation, but their function in dendritic cells in unknown. In this study, the authors used tofacitinib, a JAK inhibitor, to assess the function of these kinases in dendritic cell activity. The results show that tofacitinib reduced the expression of CD80/CD86 by suppressing the activation of interferon regulatory factor (IRF)-7 and production of type 1 interferon (IFN), and also decreased T cell stimulatory capability. This suggests a nov...