Decernotinib is an inhibitor of Janus kinase 3 (JAK3) discovered through a process of inhouse screening of a chemical compound library. Decernotinib also had the name VX-509 in development phase. It is an experimental drug with high selectivity for JAK3, which demonstrates good efficacy in vivo in the rat host versus graft model (HvG). It is being studied in clinical trials at Vertex.
^Farmer, Luc J.; Ledeboer, Mark W.; Hoock, Thomas; Arnost, Michael J.; Bethiel, Randy S.; Bennani, Youssef L.; Black, James J.; Brummel, Christopher L.; Chakilam, Ananthsrinivas (2015-09-24). "Discovery of VX-509 (Decernotinib): A Potent and Selective Janus Kinase 3 Inhibitor for the Treatment of Autoimmune Diseases". Journal of Medicinal Chemistry. 58 (18): 7195–7216. doi:10.1021/acs.jmedchem.5b00301. ISSN0022-2623. PMID26230873.