A Study of Sacituzumab Tirumotecan (MK-2870) as a Single Agent and in Combination With Pembrolizumab (MK-3475) Versus Treatment of Physician's Choice in Participants With HR+/HER2- Unresectable Locally Advanced or Metastatic Breast Cancer (MK-2870-010)

What this study is about

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.

Who can join (things the study team will check)

✅ You may be able to join if…

• 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

🚫 You may not be able to join if…

• 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

Where this trial is running

• Ironwood Cancer & Research Centers ( Site 0066), Chandler, Arizona, United States
• Banner MD Anderson Cancer Center-Oncology ( Site 0004), Gilbert, Arizona, United States
• Providence Medical Foundation-Oncology ( Site 0020), Fullerton, California, United States
• Moores Cancer Center ( Site 0059), La Jolla, California, United States
• Cancer and Blood Specialty Clinic ( Site 0001), Los Alamitos, California, United States
• University of Colorado Anschutz Medical Campus ( Site 0061), Aurora, Colorado, United States
• UCHealth Cherry Creek Medical Center ( Site 0094), Denver, Colorado, United States
• University of Colorado Health - Highlands Ranch Hospital ( Site 0095), Highlands Ranch, Colorado, United States
• Yale Cancer Center ( Site 0060), New Haven, Connecticut, United States
• Stamford Hospital ( Site 0049), Stamford, Connecticut, United States
• AdventHealth Altamonte Springs ( Site 0021), Altamonte Springs, Florida, United States
• University of Florida College of Medicine ( Site 0063), Gainesville, Florida, United States

+ 247 more sites.

Who to contact

Toll Free Number · 1-888-577-8839 · Trialsites@msd.com

It's completely normal to call and ask questions before deciding anything. Mention the study ID: NCT06312176.