AZD2281 (olaparib) is phthalazinone-based PARP inhibitor with a potencies of 5 nM and 1 nM for PARP1 and PARP2, respectively. It has been shown to be efficacious in the treatment of breast cancer tumors with BRCA mutations. Specifically, BRCA2 deficient tumor cells showed the strongest differential growth inhibition upon treatment with AZD2281 when compared to BRCA2-proficient cells. [1]

AZD2281 has been studied in combination therapies with platinum-based drugs and taxanes; specifically, synergistic toxicity in BRCA2-deficient cells has been shown with cisplatin. [1] AZD2281 has been shown to be a radiosensitizer in the treatment of NSCLC cells. [2]