This study is looking at a specific type of breast cancer called triple-negative breast cancer that has spread to other parts of the body or cannot be removed by surgery. Triple-negative breast cancer is a form of breast cancer where the cancer cells do not have certain proteins on their surface, which makes it different from other types of breast cancer. The study focuses on patients whose cancer tests positive for a marker called PD-L1, which is a protein found on some cancer cells. The treatment being studied involves a combination of three medications given through a vein: zimberelimab (also known by the code name AB122), domvanalimab (also known by the code name AB154), and sacituzumab govitecan (marketed as Trodelvy). These medications work in different ways to help the body fight cancer cells. This combination is being tested as the first treatment for patients who have not yet received any therapy for their advanced disease.
The main goal of this study is to find out how well this three-drug combination works in shrinking or stopping the growth of tumors in patients with this specific type of breast cancer. The study will measure how many patients experience a reduction in the size of their tumors or have their tumors disappear completely. The researchers will also look at how long patients live without their disease getting worse, how long patients survive overall, and how long any positive response to treatment lasts. Additionally, the study will examine the safety of this treatment combination and any side effects that may occur.
Patients in this study will receive the three medications through infusions into a vein at specific time intervals over a treatment period that can last up to twelve months. Throughout the study, patients will have regular check-ups that include imaging scans such as CT scans or MRI scans to see how the tumors are responding to treatment. Blood and stool samples will be collected at various points during the study. Patients will also need to provide a tissue sample from their tumor, either from a previous biopsy or from a new biopsy taken before treatment starts. The study requires that patients have measurable disease that can be tracked using imaging tests, and they must not have received any previous treatment for their advanced cancer, although some prior treatment in earlier stages of the disease is allowed if enough time has passed.



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