Researchers are looking for new ways to treat types of breast cancer that are both:
* High-risk, which means the cancer may have a higher chance of getting worse or coming back after treatment * Early-stage, which means the cancer is in the breast or the lymph nodes around the breast The 2 types of breast cancer in this study are triple-negative breast cancer (TNBC) and hormone receptor (HR)-low positive/human epidermal growth factor receptor-2 (HER2) negative breast cancer. These cancers have zero or a low amount of a protein called HER2 and other proteins that attach to the hormones estrogen or progesterone.
Sacituzumab tirumotecan (also known as sac-TMT or MK-2870), the study medicine, is a type of targeted therapy. A targeted therapy is a treatment that works to control how specific types of cancer cells grow and spread.
The main goals of this study are to learn if people who receive sac-TMT, pembrolizumab, and chemotherapy:
* Have fewer cancer cells found in the tumors and lymph nodes removed during surgery compared to those who receive only pembrolizumab and chemotherapy * Live longer without the cancer growing, spreading, or coming back compared to people who receive only pembrolizumab with chemotherapy
cT1c, N1-N2
cT2, N0-N2
cT3, N0-N2
cT4a-d, N0-N2
Metastatic (Stage IV) breast cancer or clinical node stage 3 (cN3) nodal involvement
Has received any prior treatment, including radiation, systemic therapy,and/or definitive surgery for currently diagnosed breast cancer
Has undergone excisional biopsy of the primary tumor, axillary lymph node dissection, and/or axillary sentinel lymph node biopsy prior to study treatment.
Received prior systemic anticancer therapy including investigational agents within 4 weeks before C1D1.