Efficacy of Pembrolizumab in HER2-Positive Gastro-Oesophageal Cancer: Results from KEYNOTE-811 Trial

date: 2024-01-01

  • Design: Randomized, Phase 3 trial involving 168 medical centers in 20 countries worldwide.
  • Number of patients: 698 patients were assigned to pembrolizumab (n=350) or placebo (n=348).
  • Patients characteristics: Patients aged 18 years or older with locally advanced or metastatic HER2-positive gastro-oesophageal junction adenocarcinoma, without previous first-line treatment.
  • Agent: Pembrolizumab 200 mg or placebo combined with standard chemotherapy (fluoropyrimidine and platinum-based therapy) plus trastuzumab every 3 weeks for up to 35 cycles or until disease progression, unacceptable toxic effects, or investigator or participant-initiated withdrawal.
  • Treatment line: First-line treatment.
  • Trial Name/NCT Number: KEYNOTE-811 trial (NCT03615326).

  • Comparison of two groups: | Endpoints | Pembrolizumab Group | Placebo Group | Hazard Ratio (HR) | P-value | | ------------------------------ | ------------------------------ | ------------------------------ | ----------------- | ------- | | Median Progressi-free survival | 10.0 months (95% CI 8.6-12.2) | 8.1 months (95% CI 7.1-8.6) | 0.73 (0.61-0.87) | 0.0002 | | Median Overall survival | 20.0 months (95% CI 17.8-22.1) | 16.8 months (95% CI 15.0-18.7) | 0.84 (0.70-1.01) | 0.084 |

  • Other findings:

    • Pembrolizumab significantly improved progression-free survival compared with placebo when combined with first-line trastuzumab and chemotherapy for metastatic HER2-positive gastro-oesophageal cancer.
    • Pembrolizumab was well-tolerated, with a manageable safety profile similar to placebo.
  • Summary: The results of the interim analysis of the KEYNOTE-811 trial showed that pembrolizumab significantly improved progression-free survival when combined with first-line trastuzumab and chemotherapy for metastatic HER2-positive gastro-oesophageal cancer. The trial is ongoing, and the final analysis will provide information on overall survival. Pembrolizumab was well-tolerated, with a manageable safety profile similar to placebo.