If you join this study, doctors will first review your medical records, scans, tumor samples, and blood tests to learn more about your cancer. Based on special features of the tumor, you will be placed into a study group that matches your type of breast cancer. You will receive standard cancer treatment that fits your cancer, such as hormone therapy with other medicines or chemotherapy. Some people may be assigned to a treatment group by chance. During the study, you will have regular clinic visits, scans every few months, blood tests, and safety checks. Treatment will continue as long as the cancer does not get worse and the side effects stay manageable.

This study is for people who have breast cancer that has spread to other parts of the body. It includes people with hormone receptor positive breast cancer and people with triple negative breast cancer. Their cancer has gotten worse even after they received their first treatment.

People can join this study if they are 18 years old or older and have breast cancer that has spread to other parts of the body. Their cancer must be either hormone receptor positive and HER2 negative or triple negative breast cancer. The cancer must have gotten worse after the first treatment, and they must not have started the next treatment yet. They also need to be well enough to take care of themselves and do daily activities with little or some help.

This study is being done to learn how different types of breast cancer respond to treatment. Each cancer is a little different, and these differences are called biomarkers. By studying tumor tissue and blood samples, researchers want to match people with treatments that are more likely to work for their specific cancer. The goal is to help people with metastatic breast cancer have better results now and improve treatment choices in the future.