The purpose of this study is to compare sacituzumab tirumotecan as a single agent, and in combination with pembrolizumab, versus Treatment of Physician's Choice (TPC) in participants with hormone receptor positive/human epidermal growth factor receptor-2 negative (HR+/HER2-) unresectable locally advanced, or metastatic, breast cancer. The primary hypotheses are that sacituzumab tirumotecan as a single agent and sacituzumab tirumotecan plus pembrolizumab are superior to TPC with respect to progression-free survival (PFS) per Response Evaluation Criteria in Solid Tumors version 1.1 (RECIST 1.1) by blinded independent central review (BICR) in all participants.
Conditions: Breast Neoplasms
Eligibility Criteria
Inclusion Criteria
- Has unresectable locally advanced or metastatic centrally-confirmed hormone receptor positive (HR+)/human epidermal growth factor receptor 2 negative (HER2-) breast cancer
- Has radiographic disease progression on one or more lines of endocrine therapy for unresectable locally advanced/metastatic HR+/HER2- breast cancer, with one in combination with a CDK4/6 inhibitor
- Is a chemotherapy candidate
- Has an eastern cooperative oncology group (ECOG) performance status of 0 to 1 assessed within 7 days before randomization
- Has adequate organ function
- Human immunodeficiency virus (HIV)-infected participants must have well controlled HIV on antiretroviral therapy
- Participants who are Hepatitis B surface antigen (HBsAg) positive are eligible if they have received HBV antiviral therapy for at least 4 weeks, and have undetectable HBV viral load
- Participants with a history of Hepatitis C virus (HCV) infection are eligible if HCV viral load is undetectable
Exclusion Criteria
- Has breast cancer amenable to treatment with curative intent
- Has experienced an early recurrence (\<6 months after completing adjuvant/neoadjuvant chemotherapy) and therefore is eligible to receive second-line (2L) treatment
- Has symptomatic advanced/metastatic visceral spread at risk of rapidly evolving into life-threatening complications
- Has received prior chemotherapy for unresectable locally advanced or metastatic breast cancer
- Active autoimmune disease that has required systemic treatment in the past 2 years
- History of (noninfectious) pneumonitis/interstitial lung disease that requires steroids, or has current pneumonitis/interstitial lung disease
- Has an active infection requiring systemic therapy
Eligibility criteria are kept as the original English records from ClinicalTrials.gov; actual eligibility is determined by the research team's formal assessment and the informed consent form. Source: ClinicalTrials.gov, updated automatically every two weeks. Last synced: 2026年10月8日.