Description: Lanraplenib (also known as GS-9876; GS-SYK) is a highly selective and orally bioavailable Spleen Tyrosine Kinase (SYK) inhibitor with IC50 of 9.5 nM). It is currently under development by Gilead for the treatment of inflammatory diseases such as RA. Spleen Tyrosine Kinase (SYK) mediates signaling in a range of hematopoietic cells involved in the initiation and progression of RA including B cells, monocytes, macrophages, dendritic cells, and osteoclasts. There is strong preclinical validation for SYK as a therapeutic target for RA based on cellular data and animal models of disease. Lanraplenib (GS-9876) inhibits SYK activity in platelets via the glycoprotein VI (GPVI) receptor without prolonging bleeding time (BT) in monkeys or humans. GS-9876 potently inhibits multiple cellular events implicated in RA pathogenesis and displays excellent in vivo efficacy in rat CIA models after once-daily dosing. GS-9876 has markedly improved selectivity over competitor SYK programs. These data support the development of GS-9876 in inflammatory diseases, with potential for an improved safety profile.