Potent inhibitor of cdk4/cyclin D1 (IC50 = 59 nM). Also active against CaM kinase II (IC50 = 25 nM) but displays selectivity over several other kinases in vitro (IC50 values for inhibition of PKA and PKC are > 2 and > 100 μM respectively). Inhibits human cytomegalovirus (HCMV) replication in vitro (IC50 = 200 nM).