P276-00-d4 is the labeled analog of P276-00 (P122480), a cyclin-dependent kinase (CDK) inhibitor. P276-00 has shown to be highly selective for cancer cells and has shown to produce potent inhibition of Cdk4-D1 activity. P276-00 also induces apoptosis in human promyelocytic leukemia (HL-60) cells.