This study is looking at patients with triple-negative breast cancer that is HER2-low and has spread to other parts of the body or has grown locally in a way that cannot be removed by surgery. Triple-negative breast cancer is a type of breast cancer where the cancer cells do not have certain receptors that are commonly found in other breast cancers, specifically having very low levels of estrogen and progesterone receptors. HER2-low means that the cancer cells have a small amount of a protein called HER2 on their surface. The study will test two medications called sacituzumab govitecan and trastuzumab deruxtecan, which are given through a vein. These medications will be given in an alternating pattern, meaning patients will switch between the two treatments rather than receiving just one continuously.

The purpose of the study is to see if using both medications in this alternating way helps patients live longer compared to using sacituzumab govitecan alone. The study will also look at how well the treatment works by measuring whether tumors shrink or stop growing, how long patients live without their cancer getting worse, and how the treatment affects their quality of life. Researchers will also carefully track any side effects or unwanted reactions that patients experience during the treatment to understand how safe and tolerable this approach is.

During the study, patients will be randomly assigned to receive either the alternating combination of both medications or sacituzumab govitecan alone. Both medications are given through an infusion into a vein, and the treatment continues for a period of weeks with regular monitoring visits. Throughout the study, doctors will perform regular check-ups, blood tests, and scans to see how the cancer is responding to treatment and to monitor the patient’s overall health and heart function. Patients will also be asked to complete questionnaires about their quality of life and how they are feeling during treatment.