MK-4827 is a potent, selective, PARP 1/2 inhibitor with IC50 of 3.8 and 2.1 nM for PARP1 and 2, respectively. MK-4827 possesses potential antineoplastic activity. In a whole cell assay, MK-4827 prevented PARP activity with an EC50 of 4 nM, enhancing the accumulation of DNA strand breaks and promoting genomic instability and apoptosis. MK-4827 induces selective synthetic lethality in homologous recombination (HR) repair deficient tumors with BRCA1/2 loss and tumor cell lines with non-BRCA-related HR defects, supporting clinical utility in sporadic tumors. MK-4827 reveals good pharmacokinetic properties and is currently in phase I clin. trials. The phase I clinical trials for MK-4827 is ongoing in the treatment of solid tumors.