Study of Sacituzumab Govitecan-hziy and Pembrolizumab Versus Treatment of Physician's Choice in Patients With Triple Negative Breast Cancer Who Have Residual Invasive Disease After Surgery and Neoadjuvant Therapy (ASCENT-05/AFT-65 OptimICE-RD/GBG 119/NSABP B-63)

Key Inclusion Criteria:

• Age > 18 years, with residual invasive triple negative breast cancer (TNBC) in thebreast or lymph nodes after neoadjuvant therapy and surgery:

• TNBC criteria for the study is defined as estrogen receptor (ER) andprogesterone receptor (PR) ≤ 10%, human epidermal growth factor receptor 2 (HER2)-negative per American Society of Clinical Oncology and College ofAmerican Pathologists (ASCO/CAP) guidelines (immunohistochemistry (IHC) and/orin situ hybridization (ISH)).

• Adequate excision and surgical removal of all clinically evident of disease in thebreast and/or lymph nodes and have adequately recovered from surgery.

• Submission of both pre-neoadjuvant treatment diagnostic biopsy and resected residualinvasive disease tissue.

• Eastern Cooperative Oncology Group (ECOG) performance status 0-1.

• Individuals must have received appropriate radiotherapy and have recovered prior tostarting study treatment.

• Adequate organ function.

Key Exclusion Criteria:

• Stage IV (metastatic) breast cancer as well as history of any prior (ipsi- orcontralateral) invasive breast cancer.

• Prior treatment with another stimulatory or coinhibitory T-cell receptor agent (eg,cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4), OX-40, cluster ofdifferentiation 137 (CD137), prior treatment with any HER2-directed agent, priorendocrine therapy for > 4 weeks or planned concurrent endocrine therapy whilereceiving on-study treatment.

• Evidence of recurrent disease following preoperative therapy and surgery.

• Prior treatment with topoisomerase 1 inhibitors or antibody-drug conjugates (ADCs)containing a topoisomerase inhibitor.

• Individuals with germline breast cancer gene (BRCA) mutations.

• Myocardial infarction or unstable angina pectoris within 6 months of enrollment orhistory of serious ventricular arrhythmia (ie, ventricular tachycardia orventricular fibrillation), high-grade atrioventricular block, or other cardiacarrhythmias or Left ventricular ejection fraction (LVEF) of < 50%

• Active serious infections requiring anti-microbial therapy.

Note: Other protocol defined Inclusion/Exclusion criteria may apply.