AZ5576 racemate is a racemic mixture of AZ5576 isomers. AZ5576 is a potent, highly selective, and orally bioavailable inhibitor of Cdk9 that inhibits Cdk9 enzyme activity with an IC50 <5nM and decreases phosphorlyation of Ser2-RNAPII in cells with an IC50 of 96nM. In the MLL-fusion containing acute myeloid leukemia (AML) line, MV411, short-term treatment with AZ5576 led to a rapid dose-dependent decrease in pSer2-RNAPII with concomitant loss of Mcl1 mRNA and protein, resulting in the cleavage and activation of caspase 3 and loss of cell viability.