NCT03675737

Pembrolizumab (MK-3475) Plus Chemotherapy Versus Placebo Plus Chemotherapy in Participants Gastric or Gastroesophageal Junction (GEJ) Adenocarcinoma (MK-3475-859/KEYNOTE-859)

A Phase 3, Randomized, Double-blind Clinical Study of Pembrolizumab (MK-3475) Plus Chemotherapy Versus Placebo Plus Chemotherapy as First-line Treatment in Participants With HER2 Negative, Previously Untreated, Unresectable or Metastatic Gastric Orgastroesophageal Junction Adenocarcinoma (KEYNOTE-859)

• Status: Completed
• Phase: Phase 3
• Study type: Interventional
• Enrollment: 1,579 (actual)
• Sponsor: Merck Sharp & Dohme LLC · Industry
• Sex: All
• Age: 18 Years
• Healthy volunteers: Not accepted

Summary

The purpose of this study is to evaluate the efficacy of pembrolizumab (MK-3745) in combination with chemotherapy (Cisplatin combined with 5-Fluorouracil \[FP regimen\] or oxaliplatin combined with capecitabine \[CAPOX regimen\]) versus placebo in combination with chemotherapy (FP or CAPOX regimens) in the treatment of human epidermal growth factor receptor 2 (HER2) negative advanced gastric or GEJ adenocarcinoma in adult participants. The primary hypotheses of this study are that pembrolizumab plus chemotherapy is superior to placebo plus chemotherapy in terms of overall survival (OS). Once a participant has achieved the study objective or the study has ended, the participant will be discontinued from this study and enrolled in an extension study (Keynote 587; NCT03486873) to continue protocol-defined assessments and treatment.

Conditions

• Stomach Neoplasms

Interventions

Type	Name	Description
BIOLOGICAL	Pembrolizumab	Administered as an IV infusion on Day 1 Q3W
DRUG	Cisplatin	Administered as an IV infusion on Day 1 Q3W
DRUG	5-fluorouracil	Administered as a continuous IV infusion on Days 1-5 Q3W
DRUG	oxaliplatin	Administered as an IV infusion on Day 1 Q3W
DRUG	capecitabine	Administered orally BID on Days 1 to 14 Q3W
DRUG	Placebo for Pembrolizumab	Administered as an IV infusion on Day 1 Q3W

Timeline

• Start date: 2018-11-08
• Primary completion: 2022-10-03
• Completion: 2025-03-03
• First posted: 2018-09-18
• Last updated: 2026-02-27
• Results posted: 2023-10-12

Locations

215 sites across 33 countries: United States, Argentina, Australia, Brazil, Canada, Chile, China, Colombia, Costa Rica, Czechia, Denmark, France, Germany, Guatemala, Hong Kong, Hungary, Ireland, Israel, Italy, Japan, Mexico, New Zealand, Peru, Poland, Russia, South Africa, South Korea, Spain, Switzerland, Taiwan, Turkey (Türkiye), Ukraine, United Kingdom

Regulatory

• FDA-regulated drug study