# Pembrolizumab for Early Triple-Negative Breast Cancer

Source: https://onco.cc/key-papers/paper-keynote-522-n-engl-j-med-2020/  
OnCo record `paper-keynote-522-n-engl-j-med-2020` (Key paper). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Published report from the KEYNOTE-522 trial registered as NCT03036488, in New England Journal of Medicine (2020), chosen as the most cited paper whose own text cites the registry id.

## Summary

Background: Previous trials showed promising antitumor activity and an acceptable safety profile associated with pembrolizumab in patients with early triple-negative breast cancer. Whether the addition of pembrolizumab to neoadjuvant chemotherapy would significantly increase the percentage of patients with early triple-negative breast cancer who have a pathological complete response (defined as no invasive cancer in the breast and negative nodes) at definitive surgery is unclear.

Methods: In this phase 3 trial, we randomly assigned (in a 2:1 ratio) patients with previously untreated stage II or stage III triple-negative breast cancer to receive neoadjuvant therapy with four cycles of pembrolizumab (at a dose of 200 mg) every 3 weeks plus paclitaxel and carboplatin (784 patients; the pembrolizumab-chemotherapy group) or placebo every 3 weeks plus paclitaxel and carboplatin (390 patients; the placebo-chemotherapy group); the two groups then received an additional four cycles of pembrolizumab or placebo, and both groups received doxorubicin-cyclophosphamide or epirubicin-cyclophosphamide. After definitive surgery, the patients received adjuvant pembrolizumab or placebo every 3 weeks for up to nine cycles. The primary end points were a pathological complete response at the time of definitive surgery and event-free survival in the intention-to-treat population.

Results: At the first interim analysis, among the first 602 patients who underwent randomization, the percentage of patients with a pathological complete response was 64.8% (95% confidence interval [CI], 59.9 to 69.5) in the pembrolizumab-chemotherapy group and 51.2% (95% CI, 44.1 to 58.3) in the placebo-chemotherapy group (estimated treatment difference, 13.6 percentage points; 95% CI, 5.4 to 21.8; P<0.001). After a median follow-up of 15.5 months (range, 2.7 to 25.0), 58 of 784 patients (7.4%) in the pembrolizumab-chemotherapy group and 46 of 390 patients (11.8%) in the placebo-chemotherapy group had disease progression that precluded definitive surgery, had local or distant recurrence or a second primary tumor, or died from any cause (hazard ratio, 0.63; 95% CI, 0.43 to 0.93). Across all treatment phases, the incidence of treatment-related adverse events of grade 3 or higher was 78.0% in the pembrolizumab-chemotherapy group and 73.0% in the placebo-chemotherapy group, including death in 0.4% (3 patients) and 0.3% (1 patient), respectively.

Conclusions: Among patients with early triple-negative breast cancer, the percentage with a pathological complete response was significantly higher among those who received pembrolizumab plus neoadjuvant chemotherapy than among those who received placebo plus neoadjuvant chemotherapy. (Funded by Merck Sharp & Dohme [a subsidiary of Merck]; KEYNOTE-522 ClinicalTrials.gov number, NCT03036488.).

Indexed on Europe PMC as PubMed record 32101663 (DOI 10.1056/nejmoa1910549). Its abstract cites the registry id NCT03036488, which is how it was matched to this trial; no figure has been checked by an editor.

## Fields

- Kind: Key paper
- Last checked: 2026-09-22
- Tags: europepmc-ingest
- Journal: New England Journal of Medicine
- Year: 2020
- DOI: 10.1056/nejmoa1910549
- Authors: Schmid P, Cortes J, Pusztai L, et al.
- What it means: This is the paper Europe PMC returns for registry id NCT03036488 with the most citations, so it is the natural first reading for anyone following the KEYNOTE-522 trial. Read the abstract above alongside the trial page and the registry entry; the record was linked automatically and its figures have not been checked by hand.
- Caveats: Matched to the trial by the registry id cited in the Europe PMC record; the summary reproduces the record's abstract and no figure has been verified against the full paper.

## Sources

- N Engl J Med 2020: https://doi.org/10.1056/nejmoa1910549
- PubMed: https://pubmed.ncbi.nlm.nih.gov/32101663/
- Europe PMC: https://europepmc.org/article/MED/32101663
- ClinicalTrials.gov NCT03036488: https://clinicaltrials.gov/study/NCT03036488

## Connected records

- trials: [KEYNOTE-522](https://onco.cc/trials/keynote-522/)
- journals: [New England Journal of Medicine](https://onco.cc/journals/nejm/)
- ideas: [ADC for residual disease after KEYNOTE-522](https://onco.cc/ideas/idea-post-neoadjuvant-adc/), [Neoadjuvant ADC + IO replacing anthracycline chemotherapy in TNBC](https://onco.cc/ideas/idea-neoadjuvant-adc-io/)

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