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Study of Pembrolizumab (MK-3475) Plus Chemotherapy Versus Placebo Plus Chemotherapy for HR+/HER2- Locally Recurrent Inoperable or Metastatic Breast Cancer (MK-3475-B49/KEYNOTE-B49)

NCT04895358 · Status: ACTIVE_NOT_RECRUITING · Phase: PHASE3 · Type: INTERVENTIONAL · Enrollment: 340

Last updated 2026-03-11

No results posted yet for this study

Summary

The safety and efficacy of pembrolizumab plus the investigator's choice of chemotherapy will be assessed compared to placebo plus the investigator's choice of chemotherapy in the treatment of chemotherapy-candidate hormone receptor-positive, human epidermal growth factor receptor 2-negative (HR+/HER2-) locally recurrent inoperable or metastatic breast cancer.

The primary hypotheses are that the combination of pembrolizumab and chemotherapy is superior to placebo and chemotherapy in regards to Progression-Free Survival (PFS) in participants with programmed cell death-ligand 1 (PD-L1) combined positive score (CPS) ≥1.

Prior to protocol amendment 7, participants who discontinued pembrolizumab/placebo with SD or better and subsequently experienced disease progression may have been eligible for up to 17 additional administrations of pembrolizumab if, upon unblinding, they were found to have received pembrolizumab, at the same dose and schedule used for the initial treatment period.

Conditions

  • Breast Neoplasms

Interventions

BIOLOGICAL

pembrolizumab

Intravenous (IV) infusion

DRUG

paclitaxel

IV infusion

DRUG

nab-paclitaxel

IV infusion

DRUG

liposomal doxorubicin

IV infusion

DRUG

capecitabine

oral administration

DRUG

normal saline

IV infusion

DRUG

dextrose

IV infusion

Sponsors & Collaborators

Principal Investigators

  • Medical Director · Merck Sharp & Dohme LLC

Study Design

Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
DOUBLE
Model
PARALLEL

Eligibility

Min Age
18 Years
Sex
ALL
Healthy Volunteers
No

Timeline & Regulatory

Start
2021-06-18
Primary Completion
2027-12-18
Completion
2027-12-18
FDA Drug
Yes

Countries

  • United States
  • Argentina
  • Australia
  • Austria
  • Brazil
  • Canada
  • Chile
  • China
  • Colombia
  • France
  • Germany
  • Greece
  • Guatemala
  • Hungary
  • Ireland
  • Israel
  • Italy
  • Japan
  • Malaysia
  • Mexico
  • Netherlands
  • Philippines
  • Poland
  • Portugal
  • Romania
  • Russia
  • South Korea
  • Spain
  • Sweden
  • Turkey (Türkiye)
  • United Kingdom

Study Locations

More Related Trials

Entities

Drugs
Companies

Read the full study record

This page highlights key information. For complete eligibility criteria, study locations, investigator contacts, and the full protocol, visit the original record on ClinicalTrials.gov.

View NCT04895358 on ClinicalTrials.gov