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Pembrolizumab/Placebo Plus Trastuzumab Plus Chemotherapy in Human Epidermal Growth Factor Receptor 2 Positive (HER2+) Advanced Gastric or Gastroesophageal Junction (GEJ) Adenocarcinoma (MK-3475-811/KEYNOTE-811)

NCT03615326 · Status: COMPLETED · Phase: PHASE3 · Type: INTERVENTIONAL · Enrollment: 738

Last updated 2025-12-11

Study results available
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Summary

The study will compare the efficacy and safety of pembrolizumab plus trastuzumab in combination with standard of care (SOC) chemotherapy versus trastuzumab in combination with SOC chemotherapy in participants with HER2-positive gastric cancer. The primary hypotheses of the study are that pembrolizumab plus trastuzumab in combination with chemotherapy is superior to trastuzumab plus chemotherapy in terms of 1) progression free survival (PFS) per Response Evaluation Criteria in Solid Tumors 1.1 (RECIST 1.1) as assessed by blinded independent central review (BICR), and 2) overall survival (OS).

Conditions

  • Gastric Neoplasms
  • Gastroesophageal Junction Adenocarcinoma

Interventions

BIOLOGICAL

Pembrolizumab

200 mg on Day 1 of each 3-week cycle as an IV infusion.

BIOLOGICAL

Placebo

Solution for IV infusion on Day 1 of each 3-week cycle.

DRUG

Cisplatin

80 mg/m\^2 on Day 1 of each 3-week cycle as an IV infusion, administered as part of FP chemotherapy regimen.

DRUG

5-FU

800 mg/m\^2/day continuous on Days 1-5 of each 3-week cycle (120 hours or per local standard), administered as part of FP chemotherapy regimen.

DRUG

Oxaliplatin

130 mg/m\^2 on Day 1 of each 3-week cycle over 2 hours as an IV infusion, administered as part of CAPOX chemotherapy regimen and as part of SOX chemotherapy regimen.

DRUG

Capecitabine

1000 mg/m\^2 as oral capsules BID on Days 1-14 of each 3-week cycle, administered as part of CAPOX chemotherapy regimen.

DRUG

S-1

Combination product of tegafur, CDHP, and Oxo. Oral capsules BID on Days 1-14 of each 3-week cycle based on body surface area (BSA): \<1.25 m\^2 BSA =40 mg, 1.25 to \<1.5 m\^2 BSA=50 mg, ≥1.5 m\^2 BSA=60 mg. Administered as part of SOX chemotherapy regimen.

BIOLOGICAL

Trastuzumab

8 mg/kg loading dose and then 6 mg/kg maintenance dose administered IV on day 1 of each 3-week cycle.

Sponsors & Collaborators

Principal Investigators

  • Medical Director · Merck Sharp & Dohme LLC

Study Design

Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
QUADRUPLE
Model
PARALLEL

Eligibility

Min Age
18 Years
Sex
ALL
Healthy Volunteers
No

Timeline & Regulatory

Start
2018-10-05
Primary Completion
2024-03-20
Completion
2025-11-12
FDA Drug
Yes

Countries

  • United States
  • Australia
  • Brazil
  • Chile
  • China
  • France
  • Germany
  • Guatemala
  • Ireland
  • Israel
  • Italy
  • Japan
  • New Zealand
  • Poland
  • Russia
  • South Korea
  • Spain
  • Turkey (Türkiye)
  • Ukraine
  • United Kingdom

Study Locations

More Related Trials

Entities

Drugs
Companies

Read the full study record

This page highlights key information. For complete eligibility criteria, study locations, investigator contacts, and the full protocol, visit the original record on ClinicalTrials.gov.

View NCT03615326 on ClinicalTrials.gov