October 2014

Tofacitinib with methotrexate in third-line treatment of patients with active rheumatoid arthritis: Patient-reported outcomes from a Phase 3 trial

Arthritis Care Res (Hoboken). 2014 Sep 3. doi: 10.1002/acr.22453. [Epub ahead of print]

For many patients with rheumatoid arthritis, improvements in pain, physical function, fatigue, and health-related quality of life (HRQoL) are more important and meaningful than improvements in joint swelling, tenderness, or inhibition of structural damage. These patient-perceived benefits of RA therapy contribute importantly to overall clinical efficacy.

This paper presents patient-reported outcomes (PROs) form the ORAL Step trail, which assessed tofacitinib 5 mg or 10 mg twice daily, or ...

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August 2014

Changes in serum creatinine in patients with active rheumatoid arthritis treated with tofacitinib: results from clinical trials

Arthritis Res Ther. 2014;16(4):R158

Despite preclinical and healthy volunteer studies of tofacitinib showing no evidence of nephrotoxicity, increases in mean serum creatinine levels have been observed in patients treated with the drug during the RA clinical development programme. This report explores the clinical significance of this change.

Serum creatinine values and renal adverse event data were pooled from patients who received =1 dose of tofacitinib either with background DMARDs or as monotherapy in five Phase 3 studie...

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Analysis of Infections and All-Cause Mortality in Phase II, III and Long-Term Extension Studies of Tofacitinib in Patients with Rheumatoid Arthritis

Arthritis Rheumatol. 2014;66(11):2924–2937

This study pools data from the global tofacitinib RA development programme (phase II, phase III and long-term extension studies) to determine the rate of infections and all-cause mortality with tofacitinib treatment. In total, 4,789 patients within these studies received tofacitinib, at varying doses and with varying duration.

The overall incidence rate of serious infections was 3.09 events/100 patient-years (95% CI 2.73–3.49), which was stable over time, with pneumonia and skin and soft...

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July 2014

Herpes Zoster and Tofacitinib Therapy in Patients with Rheumatoid Arthritis

Arthritis Rheumatol. 2014 Jun 18. [Epub ahead of print]

It is well established that patients with RA are at an increased risk of herpes zoster (HZ). What is less well known is whether some of the newer therapies available for treatment of RA increase this risk. Tofacitinib has been reported to be associated with an increased risk of HZ and this study quantifies that risk and reviews potential factors that represent an increased risk. Using data from the tofacitinib RA development programme; phase 2, 3, and long-term extension clinical trials, over 20...

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Tofacitinib Versus Methotrexate In Rheumatoid Arthritis

N Engl J Med. 2014;370(25):2377–2386.

ORAL Start is the latest trial to be reported in the tofacitinib clinical development programme. It compares the use of tofacitinib monotherapy to MTX monotherapy, in RA patients who have had either no or a sub-therapeutic dose of MTX in the past. Nine hundred and fifty eight patients received either tofacitinib (5 mg or 10 mg) twice daily, or methotrexate at a dose that was incrementally increased to 20 mg per week over 8 weeks. The co primary efficacy endpoints were ACR 70 response, and mean c...

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June 2014

Mechanism of Activation of Protein Kinase JAK2 by the Growth Hormone Receptor

Science 344, 2014; doi: 10.1126/science.1249783

Class I cytokine receptors are key regulators of many processes within the body. The receptors use the JAK-STAT signalling pathway, the deregulation of which causes it to become an important pathway in oncogenesis. Despite this, the processes responsible for JAK2 activation by class I receptors remains elusive. Previous studies using growth hormone and its receptor have led to a model of receptor activation where hormone induced receptor dimerization resulted in close proximity of the receptor i...

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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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May 2014

JAK2-STAT3 Blockade by AG490 Suppresses Autoimmune Arthritis in Mice via Reciprocal Regulation of Regulatory T cells and Th17 cells

J Immunol 2014; 192:4417-4424

In this study, Park et al sought to investigate the effects of the JAK2 inhibitor, AG490 in RA. Using murine CIA models, both preventative and therapeutic models were investigated. In the preventative model, CIA mice treated with AG490 showed a significantly lower incidence rate of arthritis and arthritic scores when compared to mice injected with vehicle. In the therapeutic model, as in the preventative, AG490 treated mice exhibited less severe arthritis. Through further experiments, it was dem...

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Safety and Efficacy of Tofacitinib, an Oral Janus Kinse Inhibitor, for the Treatment of Rheumatoid Arthritis, in Open-Label Longterm Extension Studies

J Rheumatol 2014;41;837-852

This study pooled data from two LTE studies involving patients who had previously participated in qualifying phase I, II and III studies. Data up to 60 months was included for safety aspects and efficacy data up to 48 months. However data for 10 mg BID and tofacitinib monotherapy was limited after 24 and 36 months respectively. Over the two studies, 4102 patients were treated for a total of 5963 patient years.Herpes zoster, both serious and non-serious, had a higher incidence rate in tofacitinib...

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