Medical Information Only. Always consult your healthcare provider before enrolling in any clinical trial.
NCT03221426 · ClinicalTrials.gov registry record · Phase 3
Study of Pembrolizumab (MK-3475) Plus Chemotherapy Versus Placebo Plus Chemotherapy in Participants With Gastric or Gastroesophageal Junction (GEJ) Adenocarcinoma (MK-3475-585/KEYNOTE-585)
A Phase 3 study, sponsored by Merck Sharp & Dohme.
- Completed
- Registry status
- Phase 3
- Development phase
- 1,007
- Enrollment target
NCT03221426: Completed Phase 3 study, sponsored by Merck Sharp & Dohme.
NCT03221426 is a Phase 3 study that has completed, run by Merck Sharp & Dohme. The registered enrollment target is 1,007 participants, above the 772-participant average among 15,282 other Phase 3 trials with a reported enrollment target (30% higher). According to ClinicalTrials.gov, the official US trial registry.
The verdict
NCT03221426, a Phase 3 study, has completed, sponsored by Merck Sharp & Dohme.
- COMPLETED
- Registry status
- Phase 3
- Development phase
- 1,007 participants
- Enrollment target
Study Summary
The purpose of this study is to evaluate the efficacy of pembrolizumab (MK-3745) in the neoadjuvant (prior to surgery) or adjuvant (after surgery) treatment of previously untreated adults with gastric and gastroesophageal junction (GEJ) adenocarcinoma. The primary study hypotheses are that: * Neoadjuvant and adjuvant pembrolizumab plus chemotherapy, followed by adjuvant pembrolizumab is superior to neoadjuvant and adjuvant placebo plus chemotherapy, followed by adjuvant placebo in terms of Event-free Survival (EFS) based on Response Evaluation Criteria in Solid Tumors Version 1.1 (RECIST 1.1), and * Neoadjuvant pembrolizumab plus chemotherapy is superior to neoadjuvant placebo plus chemotherapy in terms of rate of Pathological Complete Response (pathCR) at the time of surgery. With Amendment 10, upon study completion, participants will be discontinued and may be enrolled in an extension study.
Primary Outcome
EFS was based on RECIST 1.1 as assessed by the investigator and was defined as the time from randomization to the first of the following events: radiographic disease progression per RECIST 1.1; local or distant recurrence as assessed by computer tomography (CT) scan or biopsy if indicated (for participants who were disease free after surgery); clinical progression as evidenced by peritoneal carcinomatosis confirmed by preoperative laparoscopy or laparotomy (for participants who were confirmed to
Interventions
- BIOLOGICAL Pembrolizumab
- DRUG Placebo
- DRUG Capecitabine
- DRUG Cisplatin
- DRUG 5-fluorouracil
Trial Details
| Field | Value |
|---|---|
| Enrollment Target | 1,007 participants |
| Start Date | 2017-10-09 |
| Est. Completion | 2025-04-23 |
| Phase | Phase 3 |
What the finished NCT03221426 record still lists
NCT03221426 is an interventional study that assigns participants to a tested intervention. Its 1,007 participants enrollment target places it among the larger protocols in the corpus, above the 772-participant average among 15,282 other Phase 3 trials with a reported enrollment target (30% higher).
The record links to 0 conditions, and to 5 interventions - of which Pembrolizumab is the first listed.
NCT03221426 does not publish any study locations in the registry export this page uses.
Frequently Asked Questions
What is clinical trial NCT03221426 about?
NCT03221426 is a clinical study titled "Study of Pembrolizumab (MK-3475) Plus Chemotherapy Versus Placebo Plus Chemotherapy in Participants With Gastric or Gastroesophageal Junction (GEJ) Adenocarcinoma (MK-3475-585/KEYNOTE-585)". The purpose of this study is to evaluate the efficacy of pembrolizumab (MK-3745) in the neoadjuvant (prior to surgery) or adjuvant (after surgery) treatment of previously untreated adults with gastric and gastroesophageal junction (GEJ) adenocarcinoma. The primary study hypotheses are that: * Neoa...
What is the current status of trial NCT03221426?
This trial is currently completed. It is a Phase 3 study. The enrollment target is 1,007 participants. The study started on 2017-10-09. Estimated completion is 2025-04-23.
What interventions are being tested in trial NCT03221426?
The interventions under investigation include: Pembrolizumab (BIOLOGICAL), Placebo (DRUG), Capecitabine (DRUG), Cisplatin (DRUG), 5-fluorouracil (DRUG).
Who is sponsoring clinical trial NCT03221426?
This trial is sponsored by Merck Sharp & Dohme, which has 558 total clinical trials registered on ClinicalTrials.gov.
Learn More About Clinical Trials
How this trial's enrollment target compares
Where NCT03221426's enrollment target sits among peer trials
1,007 295th of 2000 higher than 1,706 of 2,000 other Phase 3 trials
participants (enrollment target), bucketed by value
Each bar is a band; taller bars hold more other Phase 3 trials. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count and share, and where it sits relative to this entry.
Source ClinicalTrials.gov registry export · 2026-08-08
Nationwide trials with similar profiles
Cross-condition peers matched on enrollment target and registry start date, not the same-condition list above.
Similar enrollment target
- NCT07191782 · 1,008 participants · NA
Examining the Efficacy of the PRAISE With Coaching Program
- NCT04389632 · 1,006 participants · Phase 1
A Study of Sigvotatug Vedotin in Advanced Solid Tumors
- NCT06207864 · 1,001 participants · NA
Engagement of American Indians of Southwestern Tribal Nations in Cancer Genome Sequencing
- NCT00018044 · 1,000 participants
Study of Mycobacterial Infections
Similar registry start date
- NCT05962346 · started 2026-12 · NA
Fetal Endoscopic Tracheal Occlusion for Congenital Diaphragmatic Hernia
- NCT07125183 · started 2026-12 · Phase 2
Study on Efficacy and Tolerability of Weekly Doxorubicin in Elderly Patients With Advanced or Metastatic Leiomyosarcoma
- NCT07292298 · started 2026-11 · Phase 2
Phase 2 Single-Arm Rectal Cancer Brachytherapy for Patients With Low-Lying Residual Adenocarcinoma After Total Neoadjuvant Therapy to Improve Organ Preservation Rates
- NCT04263285 · started 2026-10 · NA
Treatment of Depression Post-SCI