Olaparib + Sapacitabine in BRCA Mutant Breast Cancer

This is a Phase I/II clinical trial. A Phase I clinical trial tests the safety of an investigational intervention and also tries to define the appropriate dose of the investigational intervention to use for further studies. "Investigational" means that the intervention is being studied. It also means that the FDA (the U.S. Food and Drug Administration) has not approved the combination of Olaparib and Sapacitabine as a treatment for any disease. The FDA (the U.S. Food and Drug Administration) has approved Olaparib as a treatment for metastatic HER2 negative breast cancer with a BRCA mutation. Olaparib is an inhibitor of PARP (poly \[adenosine diphosphate-ribose\] polymerase), which means that it stops PARP from working. PARP is an enzyme (a type of protein) found in the cells of the body. In normal cells when DNA is damaged, PARP helps to repair the damage. The FDA has not approved Sapacitabine for use in patients including people with this type of cancer. Sapacitabine and drugs of its class have been shown to have antitumor properties in many types of cancer, e.g., leukemia, lung, breast, ovarian, pancreatic and bladder cancer. Sapacitabine may help to stop the growth of some types of cancers. In this research study, the investigators are evaluating the safety and effectiveness of Olaparib in combination with Sapacitabine in BRCA mutant breast cancer.