To make the assessment more clinically relevant, we determined the ability of compounds 1–3 to inhibit the colony-forming ability of human primary leukemia cells from an AML patient with MLL-ENL fusion oncogene; 104 primary leukemia cells were plated in Methocult H4434 methylcellulose medium containing increasing concentrations of compounds 1–3 and colonies in each culture dish were counted after 14 days. Here, KMT2A is linked to acute myeloid leukemia.