A Phase III, Active-Controlled Study of SHR-A1811 Versus Trastuzumab Emtansine (T-DM1) in HER2-Positive Primary Breast Cancer Participants With Residual Invasive Disease Following Neoadjuvant Therapy

This trial is comparing a new antibody-drug therapy (SHR-A1811) to the standard treatment (T-DM1) in women with HER2-positive breast cancer who still had cancer remaining after their pre-surgery chemotherapy. **You may be eligible if...** - You are a woman aged 18–75 with HER2-positive breast cancer confirmed by pathology - You had at least 6 cycles of pre-surgery chemotherapy including at least 9 weeks of trastuzumab (anti-HER2 therapy) - You still had cancer in the breast or lymph nodes after surgery - Your surgery was completed 3–12 weeks before starting the study drug - You have good overall health based on lab tests **You may NOT be eligible if...** - You had complete clearance of cancer after surgery (pathologic complete response) - You received fewer cycles of pre-surgery chemotherapy than required - Your cancer stage before treatment was T1N0 (very small tumor, no lymph node involvement) Talk to your doctor to see if this trial is right for you.