EPZ015866(GSK591)产品是EPZ015866 (GSK591) is a potent selective inhibitor of the arginine methyltransferase PRMT5/MEP50 complex thus stopping the methylation of histone H4 with IC₅₀ of 11 nM. It also maintains superior selectivity against other panels of methyl transferases inhibiting the symmetric arginine methylation of SmD3 with EC₅₀ of 56 nM.