Niraparib tosylate (MK-4827) is a highly potent PARP inhibitor with IC50 of 3.8 nM/2.1 nM for PARP1/PARP2.
Niraparib inhibits PARP activity with EC50=4 nM in a whole cell assay, and inhibits proliferation of cancer cells with mutant BRCA-1 and BRCA-2 with CC50 in the 10−100 nM range.
Niraparib is well tolerated in vivo and demonstrates efficacy as a single agent in a xenograft model of BRCA-1 deficient cancer.
