EED226

EED226 is a polycomb repressive complex 2 (PRC2) inhibitor, which binds to the K27me3-pocket on embryonic ectoderm development (EED) and shows strong antitumor activity in xenograft mice model^[1]. EED226 is a potent, selective, and orally bioavailable EED inhibitor^[2]. EED226 inhibits PRC2 with an IC₅₀ of 23.4 nM when the H3K27me0 peptide is used as a substrate in the in vitro enzymatic assays^[3]. IC50 & Target: IC50: 23.4 nM (PRC2)^[3] In Vitro: EED226 is a highly potent, efficient and selective inhibitor of EZH2 and EZH1 evaluated against a broad range of epigenetic and non-epigenetic targets. It potently reduces global H3K27Me3 mark in cells and demonstrates selectively cell killing effects in cells carrying a heterozygous Y641N mutation. EED226 has moderate permeability as the measured in Caco-2 cells at A→B=3.0x10^-6 cm/s, with an efflux ratio at 7.6^[2].
In the in vitro enzymatic assays, EED226 inhibited PRC2 with an IC50 of 53.5 nM when the mononucleosome is used as the substrate, with the stimulatory H3K27me3 added at 1× K_act (1.0 μM)^[3]. In Vivo: EED226 induces robust and sustained tumor regression in EZH2^MUT pre-clinical DLBCL model. In CD-1 mice, dosing of EED226 for 14 days at 300 mg/kg bid is well tolerated with no apparent adverse effects. It has very low in vivo clearance, and approximately 100% oral bioavailability. EED226 has low volume of distribution (0.8 L/kg), reasonable terminal t_1/2 (2.2 h), and moderate plasma protein binding (PPB)^[2].