Keiko Ohga

A pyrazole derivative, YM-58483, potently inhibits store-operated sustained Ca2+ influx and IL-2 production in T lymphocytes

In nonexcitable cells, Ca2+ entry is mediated predominantly through the store depletion-dependent Ca2+ channels called store-operated Ca2+ (SOC) or Ca2+ release-activated Ca2+ channels. YM-58483, a pyrazole derivative, inhibited an anti-CD3 mAb-induced sustained Ca2+ influx in acute T cell leukemia, Jurkat cells. But it did not affect an anti-CD3 mAb-induced transient intracellular Ca2+ increase in Ca2+-free medium, nor anti-CD3 mAb-induced phosphorylation of phospholipase Cγ1. It was suggested that YM-58483 inhibited Ca2+ influx through SOC channels without affecting the TCR signal transduction cascade. Furthermore, YM-58483 inhibited thapsigargin-induced sustained Ca2+ influx with an IC50 value of 100 nM without affecting membrane potential. YM-58483 inhibited by 30-fold the Ca2+ influx through SOC channels compared with voltage-operated Ca2+ channels, while econazole inhibited both SOC channels and voltage-operated Ca2+ channels with an equivalent range of IC50 values. YM-58483 potently inhibited IL-2 production and NF-AT-driven promoter activity, but not AP-1-driven promoter activity in Jurkat cells. Moreover, this compound inhibited delayed-type hypersensitivity in mice with an ED50 of 1.1 mg/kg. Therefore, we concluded that YM-58483 was a novel store-operated Ca2+ entry blocker and a potent immunomodulator, and could be useful for the treatment of autoimmune diseases and chronic inflammation. Furthermore, YM-58483 would be a candidate for the study of capacitative Ca2+ entry mechanisms through SOC/CRAC channels and for identification of putative Ca2+ channel genes.

Characterization of YM-58483/BTP2, a novel store-operated Ca2+ entry blocker, on T cell-mediated immune responses in vivo

YM-58483/BTP2 is a blocker of store-operated Ca2+ entry (SOCE), which regulates the activation of non-excitable cells such as lymphocytes. YM-58483 has been reported to inhibit cytokine production and proliferation in T cells, and to be useful as a probable medicinal candidate for treatment of bronchial asthma. The present study investigated the pharmacological profile and therapeutic potential of YM-58483 in relation to cell-mediated immune responses. In the mouse graft-versus-host disease (GVHD) model, YM-58483 (1-30 mg/kg, p.o.) and cyclosporine A (1-30 mg/kg, p.o.) inhibited donor anti-host cytotoxic T lymphocyte (CTL) activity and IFN-gamma production, and also reduced the number of donor T cells, especially donor CD8+ T cells, in the spleen. YM-58483 and cyclosporine A inhibited T cell proliferation in a one-way mixed lymphocyte reaction (MLR) with IC50 values of 330 and 12.7 nM, respectively. Additionally, YM-58483 (1-10 mg/kg, p.o.) and cyclosporine A (2, 10 mg/kg, p.o.) inhibited the sheep red blood cell (SRBC)-induced delayed type hypersensitivity (DTH) response. These results suggest that the inhibition of SOCE leads to the prevention of antigen-induced T cell responses, which participate in autoimmune diseases such as autoimmune hepatitis and rheumatoid arthritis.

Novel 7H-pyrrolo[2,3-d]pyrimidine derivatives as potent and orally active STAT6 inhibitors.

Signal transducers and activators of transcription 6 (STAT6) is an important transcription factor in interleukin (IL)-4 signaling pathway and a key regulator of the type 2 helper T (Th2) cell immune response. Therefore, STAT6 may be an excellent therapeutic target for allergic conditions, including asthma and atopic diseases. Previously, we reported 4-aminopyrimidine-5-carboxamide derivatives as STAT6 inhibitors. To search for novel STAT6 inhibitors, we synthesized fused bicyclic pyrimidine derivatives and identified a 7H-pyrrolo[2,3-d]pyrimidine derivative as a STAT6 inhibitor. Optimization of the pyrrolopyrimidine derivatives led to identification of 2-[4-(4-{[7-(3,5-difluorobenzyl)-7H-pyrrolo[2,3-d]pyrimidin-2-yl]amino}phenyl)piperazin-1-yl]acetamide (24, AS1810722) which showed potent STAT6 inhibition and a good CYP3A4 inhibition profile. Compound 24 also inhibited in vitro Th2 differentiation without affecting type 1 helper T (Th1) cell differentiation and eosinophil infiltration in an antigen-induced mouse asthmatic model after oral administration.

Identification of 4-benzylamino-2-[(4-morpholin-4-ylphenyl)amino]pyrimidine-5-carboxamide derivatives as potent and orally bioavailable STAT6 inhibitors

Signal transducers and activators of transcription 6 (STAT6) is a key regulator of the type 2 helper T (Th2) cell immune response and a potential therapeutic target for allergic diseases such as asthma and atopic diseases. To search for potent and orally bioavailable STAT6 inhibitors, we synthesized a series of 4-benzylaminopyrimidine-5-carboxamide derivatives and evaluated their STAT6 inhibitory activities. Among these compounds, 2-[(4-morpholin-4-ylphenyl)amino]-4-[(2,3,6-trifluorobenzyl)amino]pyrimidine-5-carboxamide (25y, YM-341619, AS1617612) showed potent STAT6 inhibition with an IC(50) of 0.70nM, and also inhibited Th2 differentiation in mouse spleen T cells induced by interleukin (IL)-4 with an IC(50) of 0.28 nM without affecting type 1 helper T (Th1) cell differentiation induced by IL-12. In addition, compound 25y showed an oral bioavailability of 25% in mouse.

YM-341619 suppresses the differentiation of spleen T cells into Th2 cells in vitro, eosinophilia, and airway hyperresponsiveness in rat allergic models

T helper (Th) 2 cells play a central role in the pathogenesis of allergic diseases such as allergic asthma, atopic dermatitis, and allergic rhinitis. We have found that YM-341619 hydrochloride, which suppressed IL-4-induced STAT6-dependent reporter gene expression, inhibited the differentiation of mouse spleen T cells into Th2 cells in vitro. YM-341619 suppressed the production of IL-4 and the expression of GATA-3 mRNA, a Th2 transcription factor, in T cells cultured with anti-CD3 antibody and anti-CD28 antibody in the presence of IL-4. In contrast, the production of IFN-gamma and the expression of T-bet mRNA, a Th1 transcription factor, in T cells cultured with anti-CD3 antibody in the presence of IL-12, were not effected by YM-341619. Orally administered YM-341619 (0.003-0.03 mg/kg) reduced the plasma IgE level of DNP-Ascaris-sensitized rats, but not the IgG(2a) level. YM-341619 suppressed IL-4 and IL-13 production in the splenocytes of these DNP-Ascaris-sensitized rats without augmenting IFN-gamma production. YM-341619 also dose-dependently suppressed eosinophil accumulation in the lung (0.003-3 mg/kg, p.o.) and airway hyperresponsiveness (0.3-3 mg/kg, p.o.) induced by repeated exposure to ovalbumin in ovalbumin-sensitized rats. These results suggest that YM-341619 has the ability to suppress allergen-induced Th2 responses by selectively inhibiting the differentiation of CD4(+) T cells into the Th2 subset.

A Business Intelligence Solution to Pharmacovigilance Signal Tracking and Management: One Mid-Size Pharma’s Experience

In 2012, the European Medicines Agency published guidelines for good pharmacovigilance practices. Within these guidelines, the Agency advised that marketing authorization holders (MAHs) establish safety signal tracking systems that capture outcomes related to signals that have been validated. Historically, MAHs have collected data and information to document signal detection and evaluation activities, and now many are developing robust approaches, to meet the guidelines, that systematically track and manage signals. Given the requirements, these systems could become highly reliant on business intelligence (BI) solutions. Expectations for these systems include the ability to document and track safety signals electronically through each step of the signal detection process, save source documents, and collect key performance indicators. They also include the ability to extract this information programmatically for regulatory or senior management reporting as well as for monitoring of compliance metrics. In addition, this type of systems-based approach facilitates resource management and assists MAHs to be regulatory inspection and audit ready. This article shares an experience of one mid-size pharmaceutical company.