Atuveciclib (BAY-1143572) is a potent and highly selective PTEFb/CDK9 inhibitor with IC50 values of 13 nM for CDK9/CycT and the ratio of IC50 values for CDK2/CDK9 is about 100. Outside the CDK family, It inhibits GSK3 kinase with IC50 values of 45 nM and 87 nM for GSK3α and GSK3β respectively.