KMT2A and leukemia: Preclinical studies of DOT1L inhibition in MLL‐rearranged AML showed remarkable effectiveness; however, inhibition of DOT1L in a phase I trial with the small molecule Pinemetostat (EPZ‐5676) produced complete remissions in only 2 of 34 patients with an MLL‐rearranged leukaemia 80.