Research table: Pembrolizumab (Keytruda) for early 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 early triple negative breast cancer at high risk of recurrence (a return of breast cancer).

Triple negative breast cancer is:

Pembrolizumab is given before breast surgery (called neoadjuvant therapy), along with chemotherapy. Studies show adding neoadjuvant pembrolizumab to neoadjuvant chemotherapy helps shrink triple negative breast cancer and may lower the risk of breast cancer recurrence.

Learn about pembrolizumab and early triple negative breast cancer treatment, including side effects.

Learn more about triple negative breast cancer.

Learn about pembrolizumab and metastatic breast cancer treatment (see the pembrolizumab and metastatic breast cancer summary research table).

Learn about the strengths and weaknesses of different types of studies.

Study selection criteria: Randomized clinical trials with at least 500 participants with early triple negative breast cancer.


Study Population
(number of participants)


Percent Surviving with No Breast Cancer Recurrence—
Chemotherapy Plus Pembrolizumab

Percent Surviving with No Breast Cancer Recurrence-
Chemotherapy Alone
(no Pertuzumab)

Absolute Improvement in Survival with No Breast Cancer Recurrence with the Addition of Pembrolizumab to Treatment with Chemotherapy

Randomized clinical trials

KEYNOTE-522 [1]






* Statistically significant difference between the 2 treatment groups


  1. Schmid P, Cortes J, Dent R, et al. for the KEYNOTE-522 Investigators. Event-free survival with pembrolizumab in early triple-negative breast cancer. N Engl J Med. 386(6):556-567, 2022.

Updated 09/28/23