HM97594 potently repressed trimethylation of H3K27 in lymphoma and myeloma cell lines... Also, HM97594 caused cell cycle G0/1 arrest and apoptosis in KARPAS-422 cells harboring EZH2 Y641 GOF mutation…HM97594 showed potent antitumor activity in KARPAS-422 lymphoma cell xenograft mouse model. Once daily orally administered HM97594 greatly inhibited tumor growth in a dose-dependent manner without body weight loss compared to the known EZH2 inhibitor.