GSK2646264 (Compound 44) is a potent and selective spleen tyrosine kinase ( SYK ) inhibitor with a pIC 50 of 7.1. GSK2646264 also inhibits other kinases with pIC 50 values of 5.4, 5.4, 5.3, 5, 4.5, <4.6 and <4.3 against LCK , LRRK2 , GSK3β , JAK2 , VEGFR2 , Aurora B and Aurora A , respectively. GSK2646264 is penetrable into the epidermis and dermis of the skin.