A Study of Enzalutamide, Enzalutamide in Combination With Mifepristone, or Chemotherapy in People With Metastatic Breast Cancer

The researchers are doing this study to find out if the study drug, enzalutamide, alone or combined with the study drug, mifepristone, is effective in treating advanced or metastatic androgen receptor-positive (AR+) triple negative breast cancer (TNBC) or estrogen receptor-low breast cancer (ER-low BC), and whether these study treatments work as well as standard chemotherapy with carboplatin, paclitaxel, capecitabine, or eribulin.