ABT-888 (Veliparib) is an orally-available, benzimidazole-based inhibitor of poly(ADP-ribose) polymerase with Ki values of 5.2 and 2.9 nM, for PARP1 and PARP2, respectively. [1] ABT-888 exhibits activity in C41 whole cells at an EC50 of 2 nM [2], and inhibits PAR formation in cells at an EC50 of 4.5 nM. [3]

ABT-888 efficiently crosses the blood-brain barrier and has been shown to potentiate DNA-damaging agents such as temozolomide, cisplatin, carboplatin, cyclophosphamide, irinotecan, and radiation. [1, 4] Treatment with temozolomide in the S phase generated higher levels of double-stranded DNA breaks and general higher levels of cytoxicity.