# KEYNOTE-811: pembrolizumab plus trastuzumab and chemotherapy for HER2-positive gastric or gastro-oesophageal junction adenocarcinoma

Source: https://onco.cc/key-papers/paper-keynote-811-janjigian-lancet-2023/  
OnCo record `paper-keynote-811-janjigian-lancet-2023` (Key paper). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Adding pembrolizumab to trastuzumab and chemotherapy improved response and progression-free survival in HER2-positive advanced gastric cancer, with the benefit concentrated in tumours that also express PD-L1.

## Summary

Phase 3 placebo-controlled trial of 698 patients with untreated HER2-positive advanced gastric or junctional adenocarcinoma randomised to pembrolizumab or placebo with trastuzumab and fluoropyrimidine-platinum chemotherapy.

Median progression-free survival was 10.0 versus 8.1 months (hazard ratio 0.72) overall and 10.8 versus 7.2 months in PD-L1 combined positive score 1 or more (hazard ratio 0.70); response was 73 versus 60 percent, and the final analysis showed an overall survival benefit in the PD-L1-positive population (20.0 versus 15.7 months).

## Fields

- Kind: Key paper
- Last checked: 2026-09-17
- Journal: The Lancet
- Year: 2023
- DOI: 10.1016/S0140-6736(23)02033-0
- Authors: Janjigian YY, Kawazoe A, Bai Y, et al.
- Findings: Median progression-free survival 10.0 vs 8.1 months; hazard ratio 0.72.; Combined positive score 1 or more: overall survival 20.0 vs 15.7 months at final analysis.
- What it means: Pembrolizumab with trastuzumab and chemotherapy is the first-line standard for HER2-positive gastric cancer with a PD-L1 combined positive score of 1 or more.
- Caveats: No benefit in PD-L1-negative tumours (about 15 percent), leading to a label restriction.

## Sources

- Lancet 2023: https://doi.org/10.1016/S0140-6736(23)02033-0
- PubMed: https://pubmed.ncbi.nlm.nih.gov/37871604/

## Connected records

- cancers: [HER2-positive gastric cancer](https://onco.cc/cancers/gastric-her2-positive/)
- drugs: [Pembrolizumab](https://onco.cc/drugs/pembrolizumab/), [Trastuzumab](https://onco.cc/drugs/trastuzumab/)
- trials: [KEYNOTE-811](https://onco.cc/trials/keynote-811/)
- journals: [The Lancet](https://onco.cc/journals/lancet/)

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