Olaparib (AZD-2281) is a chemotherapeutic agent developed by KuDOS Pharmaceuticals and later by Astra Zeneca. It is an inhibitor of PARP, an enzyme involved in DNA repair. It acts against cancers in people with hereditary BRCA1 or BRCA2 mutations, which includes many ovarian, breast and prostate cancers. Early (Phase I) trials have been promising, and it is now in Phase II trials, but is not clinically approved.