Anlotinib With Trastuzumab Deruxtecan for Previously Treated HER2-Low Advanced Breast Cancer

This study is testing a combination of two targeted cancer drugs — anlotinib (an anti-angiogenic drug that cuts off the blood supply to tumors) and trastuzumab deruxtecan (T-DXd, an antibody-drug conjugate that targets HER2) — in people with advanced breast cancer that has low levels of HER2 (a protein found on some cancer cells). This combination has not been tested before and researchers hope it may be more effective than either drug alone. **You may be eligible if:** - You are between 18 and 75 years old and in good physical condition - You have unresectable (cannot be removed by surgery) or metastatic breast cancer - Your cancer has low HER2 expression (IHC 1+ or IHC 2+ without gene amplification, or between 0 and 1+) - Your cancer is either hormone receptor-positive or negative - You have already received at least one prior chemotherapy treatment for your advanced/metastatic disease and it is no longer helping - You have at least one measurable tumor lesion **You may NOT be eligible if:** - You have previously been treated with anti-angiogenic targeted drugs - You have previously received an antibody-drug conjugate with a topoisomerase I inhibitor (like T-DXd or similar) - You have had or currently have interstitial lung disease or pneumonitis - You have significant unresolved side effects from previous treatments Talk to your doctor to see if this trial is right for you.