The drug being tested in this study is called MLN0128. MLN0128 is being tested to treat postmenopausal women with advanced or metastatic estrogen receptor (ER) positive, human epidermal growth factor receptor-2 (HER2) negative breast cancer that has progressed during or after aromatase inhibitor (AI) therapy. This study will evaluate the efficacy and safety of combination of fulvestrant + daily MLN0128 and fulvestrant + weekly MLN0128 compared with fulvestrant alone.