# KEYNOTE-355: pembrolizumab plus chemotherapy for PD-L1-positive advanced triple-negative breast cancer

Source: https://onco.cc/key-papers/paper-keynote-355-nejm-2022/  
OnCo record `paper-keynote-355-nejm-2022` (Key paper). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Adding pembrolizumab to first-line chemotherapy lengthened survival by almost seven months in advanced triple-negative breast cancer whose tumours had a PD-L1 combined positive score of 10 or more.

## Summary

Phase 3 placebo-controlled trial of 847 patients with previously untreated locally recurrent inoperable or metastatic triple-negative breast cancer randomised 2:1 to pembrolizumab or placebo with nab-paclitaxel, paclitaxel or gemcitabine-carboplatin.

In patients with a combined positive score of 10 or more, median overall survival was 23.0 versus 16.1 months (hazard ratio 0.73); no significant benefit was seen at lower PD-L1 scores.

## Fields

- Kind: Key paper
- Last checked: 2026-09-17
- Journal: New England Journal of Medicine
- Year: 2022
- DOI: 10.1056/NEJMoa2202809
- Authors: Cortes J, Rugo HS, Cescon DW, et al.
- Findings: Median overall survival 23.0 vs 16.1 months in combined positive score 10 or more; hazard ratio 0.73.; Median progression-free survival 9.7 vs 5.6 months in the same group.
- What it means: PD-L1 testing with the combined positive score decides first-line treatment in metastatic triple-negative breast cancer; pembrolizumab-chemotherapy is the standard for scores of 10 or more.
- Caveats: No benefit demonstrated below a combined positive score of 10.; The chemotherapy partner was chosen by the investigator.

## Sources

- N Engl J Med 2022: https://doi.org/10.1056/NEJMoa2202809
- PubMed: https://pubmed.ncbi.nlm.nih.gov/35857659/

## Connected records

- cancers: [Metastatic triple-negative breast cancer](https://onco.cc/cancers/tnbc-metastatic/)
- drugs: [Pembrolizumab](https://onco.cc/drugs/pembrolizumab/)
- trials: [KEYNOTE-355](https://onco.cc/trials/keynote-355/)
- journals: [New England Journal of Medicine](https://onco.cc/journals/nejm/)

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