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

This study is testing whether enzalutamide (a hormone-targeting drug) — alone or combined with mifepristone — can treat a specific type of metastatic breast cancer (triple-negative or low-estrogen breast cancer) that tests positive for androgen receptors (AR-positive). The study also compares this to standard chemotherapy options. **You may be eligible if...** - You are 18 years or older (male or female) - You have confirmed advanced or metastatic breast cancer that is triple-negative (ER/PR negative) or has very low estrogen receptor expression (1–10%) - Your tumor is HER2-negative - Your tumor tests positive for androgen receptors (AR-positive, at least 10%) - You have measurable or evaluable disease on imaging - You have previously received at least one treatment for advanced/metastatic disease - You are eligible for at least one standard chemotherapy option **You may NOT be eligible if...** - Your tumor is HER2-positive - Your tumor does not have androgen receptors - You have no measurable disease on imaging (e.g., only bone marrow or fluid involvement) Talk to your doctor to see if this trial is right for you.