A Trial to Evaluate Sacituzumab Govitecan in Combination With Endocrine Therapy in Patients With HR-positive, HER2-negative Metastatic Breast Cancer Progressed on CDK4/6 Inhibitors

Sacituzumab Govitecan 10 mg/kg intravenously on Days 1 and 8 of 21-day cycles Combined with Fulvestrant 500 mg intramuscularly into the buttock on Day 1 of 28-day cycles and Cycle 1 Day 15

Sacituzumab Govitecan 10 mg/kg intravenously on Days 1 and 8 of 21-day cycles Combined with One of the Two Investigator's choice of aromatase inhibitors (ICAI), orally, once daily: Anastrozole 1 mg Exemestane 25 mg