This study investigates the effects of an investigational medication in patients with triple-negative breast cancer (TNBC). Triple-negative breast cancer is a type of cancer that does not have estrogen receptors, progesterone receptors, or HER2 protein, which are common targets in other breast cancer treatments. The purpose of this study is to compare the survival of patients with TNBC who receive the investigational medication after chemotherapy to those who do not, focusing on both the entire study population and a subgroup with a specific protein called PD-L1.

Participants in the study will be randomly assigned to different study arms. One group will receive the investigational medication for one year, while the other group will not receive it. The study will involve procedures such as collecting tumor tissue samples to test for PD-L1, a protein that may affect how the investigational medication works. This will help determine the impact of the medication on the cancer.

• Who can participate: Patients with triple-negative breast cancer having residual disease of at least 1 cm or positive lymph nodes post-chemotherapy are eligible. They must not have metastatic or recurrent disease and should provide tissue samples for testing.
• Study details: Participants will be divided into study arms, with one group receiving the investigational medication and the other not receiving it. A placebo will not be used in this study. Tumor samples will be collected to test for specific proteins.