Overview

“A Phase 3, Randomized, Open-label, Study to Compare the Efficacy and Safety of Adjuvant MK-2870 in Combination with Pembrolizumab (MK-3475) Versus Treatment of Physician’s Choice (TPC) in Participants With Triple-Negative Breast Cancer (TNBC) Who Received Neoadjuvant Therapy and Did Not Achieve a Pathological Complete Response (pCR) at Surgery”

Who This Study Is For

This study is for people with triple‑negative breast cancer (TNBC) who received treatment before surgery (called neoadjuvant therapy) but still had some cancer remaining at the time of surgery. The goal is to find out whether adding a new drug, MK‑2870, to pembrolizumab (an immunotherapy) works better than the usual treatment options given after surgery.

What The Study Is Testing

Researchers want to compare two different post‑surgery (adjuvant) treatment approaches:

MK‑2870 plus pembrolizumab
Standard care, which may include:
- Pembrolizumab alone, or
- Pembrolizumab plus capecitabine (an oral chemotherapy)

Participants will be randomly assigned—like flipping a coin—to one of these two groups. About 1,530 people will take part.

Why This Study Is Being Done

The main question is whether the combination of MK‑2870 and pembrolizumab can better prevent the cancer from coming back compared with the standard treatment options. The study will measure something called invasive disease‑free survival, which looks at how long participants stay free from cancer returning or spreading.

How Participants Are Grouped

To make sure the study compares similar types of patients, participants will be grouped based on:

How much cancer was left after surgery, including tumor size and lymph node involvement
TROP2 levels, a protein measured in the tumor
Whether their doctor plans to use capecitabine as part of standard care

What Each Treatment Involves

MK‑2870 + Pembrolizumab Group
MK‑2870 is given by IV every 2 weeks
Pembrolizumab is given by IV every 6 weeks
Standard Care Group
Pembrolizumab every 6 weeks
Some participants may also receive capecitabine tablets (taken twice daily for 2 weeks on, 1 week off, in repeating cycles)

What Participation Means

If you join the study, you will receive one of the treatment options above and be followed closely by the study team. The goal is to learn which approach offers the best chance of preventing TNBC from returning after surgery.