This clinical trial is focused on studying a type of breast cancer known as HR-positive/HER2-negative high-risk early breast cancer. The study is investigating a treatment called Patritumab deruxtecan (U3-1402), which is a medication given through an injection. This medication is being tested either alone or in combination with another treatment called endocrine therapy, which involves using hormones to treat cancer. The purpose of the study is to evaluate how effective this treatment is when given to patients who have not yet received any other treatment for their breast cancer.
Participants in the study will receive the treatment as a neoadjuvant therapy, which means it is given before the main treatment, such as surgery, to help shrink the tumor. The study will involve regular monitoring and assessments to see how the cancer responds to the treatment. This includes using imaging techniques like MRI to check the size of the tumor and other tests to evaluate the cancer’s characteristics. The study will also look at the overall response of the tumor to the treatment and any changes in the cancer’s behavior over time.
The trial aims to gather information on the effectiveness of Patritumab deruxtecan in reducing the size of the tumor and improving the chances of successful surgery. It will also assess the safety of the treatment and any side effects that may occur. The study is expected to continue for several years to collect comprehensive data on the long-term outcomes for patients receiving this treatment. Participants will be closely monitored throughout the study to ensure their safety and to gather valuable information that could help improve treatment options for breast cancer in the future.



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