Zeparib 150 mg Tablet ZEPARIB 150 contains Olaparib, a potent inhibitor of human poly (ADP-ribose) polymerase enzymes (PARP1, PARP2, and PARP3). PARP enzymes are essential for the cellular repair of single-strand DNA breaks. When olaparib inhibits PARP, DNA single-strand breaks persist, leading to double-strand breaks during replication. In cells with homologous recombination repair (HRR) deficiencies, such as those harboring deleterious or suspected deleterious germline or somatic BRCA1/2 mutations, these double-strand breaks cannot be repaired accurately, accumulating double-stranded DNA damage that induces synthetic lethality and selective apoptosis of tumor cells. ZEPARIB 150 is indicated as maintenance treatment for deleterious or suspected deleterious germline or somatic BRCA-mutated advanced epithelial ovarian, fallopian tube, or primary peritoneal cancer, homologous recombination deficiency (HRD)-positive advanced ovarian cancer, germline BRCA-mutated HER2-negative metastatic breast cancer, germline BRCA-mutated metastatic pancreatic adenocarcinoma, and HRR gene-mutated metastatic castration-resistant prostate cancer (mCRPC).