A Phase III Trial Comparing HRS-8080 With Standard Endocrine Therapy in Patients With Intermediate or High Risk Early Breast Cancer

This trial tests whether HRS-8080, a new hormone-blocking drug, is better than standard hormone therapy at preventing early-stage ER-positive, HER2-negative breast cancer from coming back after surgery. **You may be eligible if...** - You are a woman between 18 and 75 years old with Stage II–III breast cancer - Your cancer was confirmed as ER+/HER2- by pathology - You have already received 2–5 years of adjuvant hormone therapy - You have no evidence of cancer recurrence or spread - You have adequate organ function and an ECOG performance status of 0 or 1 - You are willing to use non-hormonal contraception if you are of childbearing potential **You may NOT be eligible if...** - Your cancer has spread to other parts of the body (Stage IV) - You have a history of another cancer within the past 5 years - You have severe lung disease or interstitial lung disease - You are HIV-positive or have certain other medical conditions Talk to your doctor to see if this trial is right for you.