A Study of Sacituzumab Tirumotecan (Sac-TMT, MK-2870) as Monotherapy and in Combination With Pembrolizumab (MK-3475) in Participants With Triple-Negative Breast Cancer (MK-2870-011/TroFuse-011)

Researchers want to know if sacituzumab tirumotecan given alone or with pembrolizumab can treat triple negative breast cancer (TNBC). The main goal of this study is to learn if people treated with sacituzumab tirumotecan alone or with pembrolizumab live longer overall or without the cancer growing or spreading compared to people treated with chemotherapy.

• : The main inclusion criteria include but are not limited to the following: * Has locally recurrent unresectable or metastatic TNBC that cannot be treated with curative intent * Has not received systemic treatment for locally recurrent unresectable or metastatic breast cancer * Participants previously treated for early-stage breast cancer must have completed all prior therapy for early-stage breast cancer with curative intent at least 6 months before the first disease recurrence * Is a candidate for treatment with pembrolizumab and one of the TPC options: paclitaxel or nab-paclitaxel or gemcitabine + carboplatin * Participants who have AEs due to previous anticancer therapies must have recovered to ≤Grade 1 or baseline with the exception of alopecia or vitiligo. Participants with endocrine-related AEs who are adequately treated with hormone replacement are eligible * Participants who are hepatitis B surface antigen (HBsAg) positive are eligible if they have received hepatitis B virus (HBV) antiviral therapy for at least 4 weeks, and have undetectable HBV viral load * Participants with history of hepatitis C virus (HCV) infection are eligible if HCV viral load is undetectable

Use the source registry for the full inclusion and exclusion criteria before discussing referral or enrolment.