Biological Activity of GS-9973

GS-9973 is a highly selective and orally efficacious Syk inhibitor(IC50= 7.7 nM) which is currently undergoing clinical evaluation for autoimmune and oncology indications.
IC50 value: 7.7 nM [1]
Target: Syk
The most advanced Syk inhibitor, R406, 1 (or its prodrug form fostamatinib, 2), has shown efficacy in multiple therapeutic indications, but its clinical progress has been hampered by dose-limiting adverse effects that have been attributed, at least in part, to the off-target activities of 1. It is expected that GS-9973 is a more selective Syk inhibitor would provide a greater therapeutic window.

References on GS-9973

[1]. Currie KS, et al. Discovery of GS-9973, a Selective and Orally Efficacious Inhibitor of Spleen Tyrosine Kinase. J Med Chem. 2014 May 8;57(9):3856-73.

[2]. Burke RT, et al. A potential therapeutic strategy for chronic lymphocytic leukemia by combining Idelalisib and GS-9973, a novel spleen tyrosine kinase (Syk) inhibitor. Oncotarget. 2014 Feb 28;5(4):908-15.