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Research table: Pembrolizumab (Keytruda) for metastatic breast cancer treatment

This summary table contains detailed information about research studies. Summary tables are a useful way to look at the science behind many breast cancer guidelines and recommendations. However, to get the most out of the tables, it’s important to understand some key concepts. Learn how to read a research table.

Introduction: Pembrolizumab is a checkpoint inhibitor immunotherapy drug used to treat some metastatic breast cancers.

Pembrolizumab in combination with chemotherapy is used to treat metastatic triple negative breast cancers that are programmed cell death ligand 1-positive (PD-L1-positive). All metastatic triple negative breast cancers are tested to learn if they are PD-L1-positive.

Compared to chemotherapy alone, pembrolizumab in combination with chemotherapy may give people with metastatic PD-L1-positive triple negative breast cancers more time before the cancer worsens.

Learn more about pembrolizumab, including its side effects.

Study selection criteria: Randomized clinical trials with 100 or more participants with metastatic triple negative breast cancer.

Table note: Objective response rates (percent of people who responded to treatment) and overall survival show data for women with triple negative breast cancers that were PD-L1-positive, defined as a combined positive score (CPS) of 10 or more.

Study

Study Population
(number of participants)

Drug(s) Used

Objective Response Rate—Percent who Responded to Treatment
(95% CI)

Overall Survival
(95% CI)

Randomized clinical trials

KEYNOTE-119 [1]

1,098

Pembrolizumab alone

18%

Overall survival at 31 months:
23%

 

 

Chemotherapy alone
(capecitabine, eribulin, gemcitabine, or vinorelbine)

9%

Overall survival at 31 months:
11%

KEYNOTE-355 [2]

847

Pembrolizumab and chemotherapy
(nanoparticle albumin-bound paclitaxel, paclitaxel, or gemcitabine–carboplatin)

53%

Overall survival at 18 months:
58%*

 

 

Chemotherapy alone
(nanoparticle albumin-bound paclitaxel, paclitaxel, or gemcitabine–carboplatin)

41%

Overall survival at 18 months:
45%*

* Statistically significant difference between the 2 treatment groups

References

  1. Winer EP, Lipatov O, Im SA, et al. for the KEYNOTE-119 investigators. Pembrolizumab versus investigator-choice chemotherapy for metastatic triple-negative breast cancer (KEYNOTE-119): a randomised, open-label, phase 3 trial. Lancet Oncol. 22(4):499-511, 2021.
  2. Cortes J, Rugo HS, Cescon DW, et al. for the KEYNOTE-355 Investigators. Pembrolizumab plus chemotherapy in advanced triple-negative breast cancer. N Engl J Med. 387(3):217-226, 2022.

Updated 09/11/23