Olaparib is an oral inhibitor of poly (ADP-ribose) polymerase enzymes, including PARP1, PARP2, and PARP3 which are involved in normal cellular homeostasis, such as DNA transcription, cell cycle regulation, and DNA repair. Olaparib has shown activity in ovarian and breast tumors with known BRCA mutations and was the first FDA approved drug in this class. Lynparza (olaparib) is indicated for treatment of gBRCA-mutated advanced ovarian cancer. Its use together with other chemotherapy medicines can lead to increased effects on the blood resulting in reduction in the numbers of white blood cells and platelets, and anaemia.