MCL1 and acute myeloid leukemia: S63845 (α(R)-[[(5S)-5-[3-chloro-2-methyl-4-[2-(4-methyl-1-piperazinyl)ethoxy]phenyl]-6-(5-fluoro-2-furanyl)thieno[2,3-d]pyrimidin-4-yl]oxy]-2-[[1-(2,2,2-trifluoroethyl)-1H-pyrazol-5-yl]methoxy]-benzenepropanoic acid) is an inhibitor of MCL-1, a pro-survival protein that is highly overexpressed in many cancer types and in AML as well [14,15].