SAR-203475 May 2020 13:04
JAK kinases play a key role in mediating signaling from cytokine receptors. Because of the importance of cytokines in promoting autoimmune and inflammatory diseases, the JAK kinases have received much attention as possible therapeutic targets for modulating the impact of cytokines on these diseases. TYK2 and JAK1 mediate signaling for a number of cytokines , including IL-12, IL-23, IL-6, IL-22, and IFN-a (20). In this study, we identified SAR-20347 as a small molecule inhibitor of TYK2/JAK1-dependent signaling, with nanomolar potency for TYK2/JAK1 and selectivity over JAK2 and JAK3 in both biochemical and cell-based assays. The pharmacokinetic profile of SAR-20347 was also favorable, demonstrating a moderate half-life of approximately 3 hours, with excellent bioavailability and distribution to tissues. In assays using human primary cells, SAR-20347 inhibited TYK2 and JAK1 activity as assessed by complete inhibition of IL-12 induced IFN-? production in PBMCs, reporter expression in an IFN-a responsive cell line, and pSTAT inhibition after stimulation with single cytokines (e.g, IL-12/pSTAT4, IL-6/pSTAT3). The in vitro profile of SAR-20347 suggests that it has the potential to be beneficial in diseases where cytokines utilizing TYK2 and JAK1 play a critical role. The marked preference for TYK2/JAK1 offers distinct advantages over other JAK inhibitors that can interfere with JAK2, since inhibition of JAK2 can cause some degree of unwanted myelosuppression, particularly anemia and thrombocytopenia.