The purpose of this study is to compare the addition of olaparib after the usual care of chemotherapy, surgery, and radiation for patients with breast cancer who have been found to carry a BRCA1 or BRCA2 mutation in their genes and have a type of breast cancer that is HER2-negative and is not sensitive to hormone treatment or is HER2-negative and is sensitive to hormone treatment.
If the cancer is sensitive to hormone treatment, the participant may receive hormone drugs as part of usual care. In this study, patients will get either
olaparib or placebo, a pill that looks like the study drug but contains no
The use of olaparib could reduce the risk of cancer coming back but it could also cause side effects. To be better than placebo, the olaparib should decrease the chance of cancer coming back as compared to the placebo.