A Study of AND019 in Women With ER Positive HER2 Negative Advanced or Metastatic Breast Cancer

This trial is testing a new oral drug called AND019 in postmenopausal women with hormone receptor-positive (ER+), HER2-negative advanced or metastatic breast cancer that has progressed on prior hormone therapy. **You may be eligible if...** - You are a postmenopausal woman with ER-positive, HER2-negative advanced or metastatic breast cancer - Your cancer has progressed on at least one prior hormone therapy - You have received no more than one prior chemotherapy regimen for advanced disease - You are in good general health (ECOG 0 or 1) - Your organs are functioning well enough to tolerate treatment **You may NOT be eligible if...** - You have previously been treated with a SERD (selective estrogen receptor degrader) drug - You have brain metastases - You have received chemotherapy, immunotherapy, or targeted therapy recently - You have a history of significant heart disease - You are currently pregnant or breastfeeding - You have active, uncontrolled infection or HIV without effective treatment Talk to your doctor to see if this trial is right for you.