KB-0742, designed by Richters et al., is a selective ATP-competitive CDK9 inhibitor.56 It shows high selectivity against CDK9 with more than 50-fold selectivity over all CDKs profile and more than 100-fold selectivity against cell-cycle CDKs (CDK1–6) (IC50 = 6 nM at 10 μM ATP condition).56 KB-0742 (1.2 μM) was sufficient to reduce RNAP II Ser2 phosphorylation and induce growth arrest of 22rv1 PCa cells. The gene discussed is CDK9; the disease is posterior cortical atrophy.