NSABP B-63/ASCENT-05/GS-US-595-6184

You may participate in this study if you have high-risk early triple negative breast cancer (TNBC) without mutations in the BRCA1 or BRCA2 gene. This study will test an investigational drug named sacituzumab govitecan in combination with pembrolizumab or pembrolizumab with or without capecitabine for participants with this type of cancer. For this study, high-risk early TNBC is defined as any presence of TNBC that still remains in the breast or lymph node tissue after receiving treatment and having surgery.

If you are eligible to participate in this study, you will be randomly assigned to receive either the investigational treatment, sacituzumab govitecan in combination with pembrolizumab, OR 1 of the following 2 treatment regimens chosen by your doctor:

• Pembrolizumab alone
• Pembrolizumab in combination with capecitabine

Your total time in the study will vary depending on how you respond to study treatment. Taking part in this study may last from 1 day up to 10 years or longer, if you agree to remain in the study, your cancer has not returned, or the study is not stopped. During study visits, you will be asked to have physical exams, receive the study drug(s), complete questionnaires, and have lab and imaging tests done.

In order to participate you must meet the following criteria:

• Are 18 years of age or older, with residual invasive triple negative breast cancer (TNBC) in the breast or lymph nodes after neoadjuvant therapy and surgery.
• Have adequate excision and surgical removal of all clinically evident of disease in the breast and/or lymph nodes and have adequately recovered from surgery.
• Have an Eastern Cooperative Oncology Group (ECOG) performance status 0-1.
• Have received appropriate radiotherapy and have recovered prior to starting study treatment.
• Have adequate organ function.

You will be excluded from the study if any of the following criteria apply to you:

• Have stage IV (metastatic) breast cancer as well as history of any prior (ipsi- or contralateral) invasive breast cancer.
• Have had prior treatment with another stimulatory or coinhibitory T-cell receptor agent , prior treatment with any HER2-directed agent, prior or concurrent treatment with any endocrine therapy agent, prior treatment with topoisomerase 1 inhibitors or antibody-drug conjugates (ADCs) containing a topoisomerase inhibitor.
• Have evidence of recurrent disease following preoperative therapy and surgery.
• Have germline breast cancer gene (BRCA) mutations.

This is a partial list of eligibility requirements. To inquire about your eligibility, please call the contact number provided. If you wish to inquire via email, please include the title of the study in your message.