JAK selectivity and the implications for clinical inhibition of pharmacodynamic cytokine signalling by filgotinib, upadacitinib, tofacitinib and baricitinib

Traves PG, Murray B, Campigotto F, Galien R, Meng A, Di Paolo JA.
Ann Rheum Dis. 2021 Mar 19:annrheumdis-2020-219012. Epub ahead of print. DOI: 10.1136/annrheumdis-2020-219012

The first study to combine in vitro inhibition of cytokine responses in whole blood with clinical pharmacokinetics of individual JAKinibs to model daily cytokine-mediated pharmacodynamic profiles in healthy individuals and patients with RA, has demonstrated that JAKinib potencies depended on cytokine stimulus, pSTAT readout and cell type. Traves and colleagues have observed that JAKinibs have unique, differential effects on specific cytokine signalling pathways, dependent on cytokine stimulus, S...

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

Covington M, He X, Scuron M, Li J, Collins R, Juvekar A, Shin N, Favata M, Gallagher K, Sarah S, Xue CB, Peel M, Burke K, Oliver J, Fay B, Yao W, Huang T, Scherle P, Diamond S, Newton R, Zhang Y, Smith.
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 recombina...

Keywords: JAK, Preclinical, Selectivity

Preferential Inhibition of JAK1 Relative to JAK3 by Upadacitinib: Exposure-Response Analyses of Ex Vivo Data From 2 Phase 1 Clinical Trials and Comparison to Tofacitinib

Mohamed MF, Beck D, Camp HS, Othman AA.
Pharmacodynamics. 2020

Ex vivo pharmacodynamic assay results demonstrated a greater selectivity of UPA on JAK1 versus JAK3 compared to TOF. This analysis conducted ex vivo stimulation of STAT3 phosphorylation by IL-6 as a measure of JAK1 activity and STAT5 phosphorylation by IL-7 as a measure of JAK1/JAK3 activity. Change in pSTAT3 and pSTAT5 were calculated at 1, 6 and 12 hours following drug administration using samples collected from healthy subjects and subjects with RA, from 2 phase 1 studies. Exposure-response...

Keywords: JAK, Upadacitinib, Preclinical, MOA

A systematic review and meta-analysis of infection risk with small molecule JAK inhibitors in rheumatoid arthritis

Bechman K, Subesinghe S, Norton S, Atzeni F, Galli M, Cope AP, Winthrop KL, Galloway JB.
Rheumatology (Oxford) 2019;58(10):1755–66

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 the...

Keywords: JAK, Baricitinib, Clinical, Safety

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

McInnes IB, Byers NL, Higgs RE, Lee J, Macias WL, Na S, Ortmann RA, Rocha G, Rooney TP, Wehrman T, Zhang X, Zuckerman SH, Taylor PC.
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 differen...

Keywords: JAK, Upadacitinib, Preclinical, Selectivity

Efficacy and Pharmacodynamic Modeling of the BTK Inhibitor Evobrutinib in Autoimmune Disease Models

Haselmayer P, Camps M, Liu-Bujalski L, Nguyen N, Morandi F, Head J, O’Mahony A, Zimmerli SC, Bruns L, Bender AT, Schroeder P, Grenningloh.
J Immunol 2019;202:2888–2906. DOI: 10.4049/jimmunol.1800583

BTK is involved in both adaptive and innate immune responses and mediates signalling of several immune receptors of relevance to RA and SLE pathogenesis. Targeting BTK is a promising approach therefore for autoimmune disorders with aberrant B cell responses. Evobrutinib is a novel, highly specific, and irreversible BTK inhibitor. In vivo and animal models showed that evobrutinib modulated B cell and innate immune cell activation, was efficacious, and prevented joint damage. The potency of evob...

Keywords: BTK, Preclinical, PK-PD

A Systematic Review and Meta-Analysis of Infection Risk with Small Molecule JAK Inhibitors in Rheumatoid Arthritis

Bechman K, Subesinghe S, Norton S, Atzeni F, Galli M, Cope AP, Winthrop KL, Galloway JB.
Rheumatology (Oxford). DOI: 10.1093/rheumatology/kez087

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...

Keywords: JAK, Tofacitinib, Clinical, Safety

Influence of Age and Renal Impairment on the Steady State Pharmacokinetics of Filgotinib, a Selective JAK1 Inhibitor

Namour F, Fagard L, Van der AA, Harrison P, Xin Y, Tasset C.
Br J Clin Pharmacol 2018 Dec;84(12):2779-2789. DOI:10.1111/bcp.13726

Age and renal impairment (RI) had limited impact on the pharmacokinetics (PK) of filgotinib (FIL) but, in subjects with severe RI, exposure to the FIL metabolite was increased. FIL is a selective JAK1 inhibitor that is extensively, rapidly and proportionately absorbed after oral dosing from 50–200mg. Its major metabolite has a similar JAK1 selectivity profile but with reduced potency. In humans, exposure to the metabolite is higher by approximately 16–20 fold compared with the pare...

Keywords: JAK, Filgotinib, Preclinical, PK-PD

JAK Inhibition as a Therapeutic Strategy for Immune and Inflammatory Diseases

Schwartz DM, Kanno Y, Villarino A, Ward M, Gadina M, O’Shea JJ.
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. ...

Keywords: JAK, Tofacitinib, Clinical, Efficacy

Pathogenetic Insights from the Treatment of Rheumatoid Arthritis

McInnes I, Schett G.
Lancet 2017;389:2328–37 DOI 10.1016/S0140-6736(17)31472-1

This review paper examines the understanding gained from looking at the effects of specific immune interventions in the treatment of RA. The introduction of novel IL-6 agents has provided the ideal opportunity to explore the distinct effect of cytokine inhibition, as opposed to receptor inhibition, at the molecular level. Mechanistic insights into TNF could also be obtained in the future with advanced molecular and informatics approaches, and future biopsy studies will be important to explore t...

Keywords: Cytokine Signalling, Preclinical, MOA

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

Takeuchi et al.
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 prim...

Keywords: JAK, Peficitinib, Clinical, Phase 2

A Randomized, Double-Blind, Placebo-Controlled, Twelve-Week, Dose-Ranging Study of Decernotinib, an Oral Selective JAK-3 Inhibitor, as Monotherapy in Patients With Active Rheumatoid Arthritis

Fleischmann RM, Damjanov NS, Kivitz AJ, et al.
Arthritis Rheumatol. 2015;67(2):334–343.

Decernotinib (VX-509; Vertex Pharmaceuticals Incorporated) is a JAK 3 inhibitor currently under investigation for its potential use in the treatment of RA. The potency and selectivity profiles of this oral compound have already been established in previous trials, so this study aimed to establish the efficacy and safety profiles of the drug, in RA patients who have had an inadequate response to at least one DMARD. Four doses; 25 mg, 50 mg, 100 mg and 150 mg, were evaluated in this placebo-contr...

Keywords: JAK, Decernotinib, Clinical, Phase 2

Selective inhibition of spleen tyrosine kinase (SYK) with a novel orally bioavailable small molecule inhibitor, RO9021, impinges on various innate and adaptive immune responses: implication for SYK inhibitors in autoimmune disease therapy

Liao C, Hsu J, Kim Y et al.
Arthritis Research and Therapy 2013 15:R146

Spleen tyrosine kinase (SYK) has already been described as a potential therapeutic target for the treatment of autoimmune diseases. Previously the SYK inhibitor fostamatinib was in clinical development for the treatment of rheumatoid arthritis, but has since been suspended. However, investigation into SYK inhibition continues with RO2091, a novel ATP-competitive inhibitor of SYK with reasonable selectivity, potency and oral bioavailability which has been shown to suppress various innate and adap...

Keywords: Cytokine Signalling, Preclinical, Selectivity

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

Fridman JS, Scherle PA, Collins R, et al.
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...

Keywords: JAK, Baricitinib, Preclinical, Selectivity