Phenanthridinone, an isoquinoline derivative, is a potent poly(ADP-ribose)polymerase 1 inhibitor. It could be considered as a potent immunomodulator, and also as the prototype of a new class of adjuncts in cancer chemotherapy.

AG-14361 binds to the catalytic domain of PARP-1 and is a potent, selective inhibitor. AG-14361 is a selective inhibitor of PARP-1 with Ki50 value <5 nM. AG-14361 is the first high-potency PARP-1 inhibitor with the specificity and in vivo activity to enhance chemotherapy and radiation therapy of human cancer.

3,4-Dihydro-5-(4-(1-piperidinyl)butoxy)-1(2H)-isoquinolinone (DPQ) is a potent Poly(ADP-ribose) polymerase (PARP) inhibitor with cardiac protective effects. 3,4-Dihydro-5-(4-(1-piperidinyl)butoxy)-1(2H)-isoquinolinone mimics nicotinamide to competitively inhibit PARP at the NAD binding site. We have demonstrated that in vivo administration of 3,4-Dihydro-5-(4-(1-piperidinyl)butoxy)-1(2H)-isoquinolinone both before and after the onset of ischemia leads to a significant reduction of infarct volume in a focal cerebral ischemia produced by middle cerebral artery (MCA) occlusion in the rat.

4-Hydroxyquinazoline is been used to inhibit PARP (poly(ADP-ribose) synthetase) which catalyzes covalent attachment of the ADP-ribose moiety of NAD+ to various proteins. This compound specifically and potently inhibits PARP-1. 4-HQN demonstrates the ability to decrease activation of transcription factor NFκB and AP-1 in lipopolysaccharide-induced shock. Mechanistic studies indicate that 4-HQN activates PI3-kinase/Akt pathway in the liver, spleen, and lung and down-regulates two elements of the MAP kinase system. Additionally, this agent has been observed to decrease ischemia-reperfusion-induced increase of protein oxidation, single-strand DNA breaks, lipid peroxidation, and mitochondrial reactive oxygen species production in the reperfusion period.

BMN-673 (8R,9S) is the (8R,9S) enantiomer of BMN-673, known as talazoparib. BMN 673 is a novel inhibitor of nuclear enzyme poly (ADP-ribose) polymerase (PARP) with potential antineoplastic activity.

Niraparib (MK-4827) displays excellent PARP 1 and 2 inhibition. Inhibition of PARP in the context of defects in other DNA repair mechanisms provide a tumor specific way to kill cancer cells. Niraparib is in development with TESARO, under licence from Merck & Co, for the treatment of cancers (ovarian, fallopian tube and peritoneal cancer, breast cancer, prostate cancer and Ewing's sarcoma). Niraparib was characterized in a number of preclinical models before moving to phase I clinical trials, where it showed excellent human pharmacokinetics suitable for once a day oral dosing, achieved its pharmacodynamic target for PARP inhibition, and had promising activity in cancer patients. It is currently being tested in phase 3 clinical trials as maintenance therapy in ovarian cancer and as a treatment for breast cancer.

Niraparib (MK-4827) displays excellent PARP 1 and 2 inhibition. Inhibition of PARP in the context of defects in other DNA repair mechanisms provide a tumor specific way to kill cancer cells. Niraparib is in development with TESARO, under licence from Merck & Co, for the treatment of cancers (ovarian, fallopian tube and peritoneal cancer, breast cancer, prostate cancer and Ewing's sarcoma). Niraparib was characterized in a number of preclinical models before moving to phase I clinical trials, where it showed excellent human pharmacokinetics suitable for once a day oral dosing, achieved its pharmacodynamic target for PARP inhibition, and had promising activity in cancer patients. It is currently being tested in phase 3 clinical trials as maintenance therapy in ovarian cancer and as a treatment for breast cancer.

Niraparib (MK-4827) displays excellent PARP 1 and 2 inhibition. Inhibition of PARP in the context of defects in other DNA repair mechanisms provide a tumor specific way to kill cancer cells. Niraparib is in development with TESARO, under licence from Merck & Co, for the treatment of cancers (ovarian, fallopian tube and peritoneal cancer, breast cancer, prostate cancer and Ewing's sarcoma). Niraparib was characterized in a number of preclinical models before moving to phase I clinical trials, where it showed excellent human pharmacokinetics suitable for once a day oral dosing, achieved its pharmacodynamic target for PARP inhibition, and had promising activity in cancer patients. It is currently being tested in phase 3 clinical trials as maintenance therapy in ovarian cancer and as a treatment for breast cancer.