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Janus kinase (JAK) is a signal transducer and activator of a protein transcription system that transduces signals from cell surface cytokine and growth factor receptors to the nucleus. Recently developed JAK inhibitors (JAKinibs) inhibit JAKs non-selectively or selectively and down-regulate the effects of corresponding ligands (i.e. cytokines and growth factors). JAKinibs are efficacious against rheumatoid arthritis and other immune-mediated inflammatory diseases and are being increasingly prescribed clinically. Regarding safety, JAKinib use is associated with common or unique changes in laboratory parameters; however, incidence rates of serious adverse drug reactions (ADRs) associated with these changes are low. Opportunistic and other infections, including tuberculosis, are the most critical ADRs of treatment with JAKinibs, and screening and monitoring of patients should be carefully performed. Incidence rates of herpes zoster (HZ) in patients receiving JAKinibs are high in Japan and Korea, and modestly high in other countries. Filgotinib may not be associated with an elevated risk for HZ, but long-term safety data are lacking. Data from clinical development programmes and post-marketing surveillance have indicated no increased risk for malignancy or serious cardiac events; however, long-term observational studies are necessary. Despite the non-elevated risk of gastrointestinal perforations, patients with older age and/or a history of diverticulitis or receiving non-steroidal anti-inflammatory drugs should be carefully evaluated to determine the risk-benefit balance. The incidence rates of venous thromboembolism with all approved doses are similar to that expected in the population, although there are discrepancies in the placebo-controlled portion of the baricitinib clinical development programmes. Regulatory agencies in the USA and Europe suggested a higher risk for thrombotic events in patients receiving JAKinibs. Pharmacokinetic studies demonstrated that dose adjustment should be considered for JAKinib use in patients with moderate-to-severe renal or hepatic dysfunction, depending on the metabolism of each drug. Long-term observational studies enrolling patients with diverse clinical backgrounds are required to strike a risk-benefit balance in clinical settings. [ABSTRACT FROM AUTHOR]

ONO-5334, a selective inhibitor of cathepsin K, is a potential new treatment for osteoporosis. The objectives of this study were to (1) develop population pharmacokinetic-pharmacodynamic (PK-PD) models for ONO-5334 using dose-ascending data from healthy postmenopausal females, (2) examine comparability of PK and/or PD profile between Caucasian and Japanese, and (3) compare PK-PD profile between immediate release tablet (IRT) and sustained release tablet (SRT). The population PK-PD models were developed for each formulation for post-dose levels of bone resorption markers (serum CTX and NTX). The data were provided from 4 phase 1 studies with total of 201 Caucasian and 94 Japanese subjects. Plasma concentrations of ONO-5334 and bone resorption markers were thoroughly evaluated in those studies. An indirect response model described relationships between bone resorption markers and plasma concentrations of ONO-5334. There was no significant difference in PK and pharmacodynamic potency (IC50) between Caucasian and Japanese. Based on the developed model, serum CTX and NTX after administration of ONO-5334 IRT or SRT were simulated, and the results showed that ONO-5334 SRT would provide comparable PD effect on bone resorption markers with lower dose relative to IRT. [ABSTRACT FROM AUTHOR]