Alisertib and Fulvestrant in Treating Patients With Hormone Receptor Positive Breast Cancer That is Metastatic or Locally Advanced and Cannot Be Removed by Surgery

This phase I trial studies the side effects and best dose of alisertib when given together with fulvestrant in treating patients with hormone positive breast cancer that has spread to other parts of the body or has spread from where it started to nearby tissue or lymph nodes and cannot be removed by surgery. Alisertib may stop the growth of tumor cells by blocking some of the enzymes needed for cell growth. Estrogen and progesterone are type of hormones made by the body and they can cause the growth of breast cancer cells. Hormone therapy using fulvestrant may fight breast cancer by lowering the amount of estrogen or progesterone the body makes. Giving alisertib together with fulvestrant may be a better treatment for breast cancer.