Olaparib is a targeted medicine taken by mouth for cancers that have a weakness in DNA repair — most often those with a BRCA1 or BRCA2 mutation. It is used as maintenance treatment for ovarian cancer after chemotherapy, for HER2-negative breast cancer with an inherited BRCA mutation, for BRCA-mutated pancreatic cancer, and for prostate cancer with certain DNA-repair mutations.
It is a PARP inhibitor: it blocks an enzyme cancer cells with faulty BRCA rely on to patch up their DNA, so those cells accumulate damage and die while normal cells, which have working BRCA, cope. Genetic testing of the tumour or blood is needed before it is prescribed for most uses.
Olaparib comes as 100 mg and 150 mg tablets and as 50 mg capsules. The two forms are absorbed differently and have different doses — they must never be swapped milligram for milligram. It is taken twice a day, continuously. Olaparib is a prescription-only medicine; a valid prescription must be provided at checkout.