Substudy 06C: A Study of Investigational Agents With Pembrolizumab (MK-3475) and Chemotherapy in Participants With First-Line Locally Advanced Unresectable/Metastatic Gastroesophageal Adenocarcinoma (MK-3475-06C/KEYMAKER-U06)
A Phase 1/2 Open-Label, Umbrella Platform Design Study of Investigational Agents With Pembrolizumab (MK-3475) and Chemotherapy in Participants With 1L Locally Advanced Unresectable/Metastatic Gastroesophageal Adenocarcinoma (Gastric Adenocarcinoma, Gastroesophageal Junction Adenocarcinoma, and Esophageal Adenocarcinoma): Substudy 06C
Sponsor: Merck Sharp & Dohme LLC
This observational or N/A phase trial investigates Esophageal Cancer and Esophageal Neoplasms and is currently actively recruiting participants. Merck Sharp & Dohme LLC leads this study, which shows 22 recorded versions since 2024 — indicating substantial longitudinal coverage. As an oncology study, it adds to the longitudinal record of treatment development for this indication.
Study Description(click to expand)The master protocol is MK-3475-U06.
The master protocol is MK-3475-U06.
Status Flow
Change History
22 versions recorded-
May 4, 2026 — Present [daily]
Recruiting
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Apr 28, 2026 — May 4, 2026 [daily]
Recruiting
Phase: PHASE1/PHASE2 → None
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Mar 2026 — Apr 2026 [monthly]
Recruiting PHASE1/PHASE2
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Feb 2026 — Mar 2026 [monthly]
Recruiting PHASE1/PHASE2
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Jan 2026 — Feb 2026 [monthly]
Recruiting PHASE1/PHASE2
▶ Show 17 earlier versions
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Dec 2025 — Jan 2026 [monthly]
Recruiting PHASE1/PHASE2
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Nov 2025 — Dec 2025 [monthly]
Recruiting PHASE1/PHASE2
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Oct 2025 — Nov 2025 [monthly]
Recruiting PHASE1/PHASE2
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Sep 2025 — Oct 2025 [monthly]
Recruiting PHASE1/PHASE2
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Aug 2025 — Sep 2025 [monthly]
Recruiting PHASE1/PHASE2
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Jul 2025 — Aug 2025 [monthly]
Recruiting PHASE1/PHASE2
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Jun 2025 — Jul 2025 [monthly]
Recruiting PHASE1/PHASE2
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May 2025 — Jun 2025 [monthly]
Recruiting PHASE1/PHASE2
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Apr 2025 — May 2025 [monthly]
Recruiting PHASE1/PHASE2
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Mar 2025 — Apr 2025 [monthly]
Recruiting PHASE1/PHASE2
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Feb 2025 — Mar 2025 [monthly]
Recruiting PHASE1/PHASE2
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Jan 2025 — Feb 2025 [monthly]
Recruiting PHASE1/PHASE2
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Dec 2024 — Jan 2025 [monthly]
Recruiting PHASE1/PHASE2
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Nov 2024 — Dec 2024 [monthly]
Recruiting PHASE1/PHASE2
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Oct 2024 — Nov 2024 [monthly]
Recruiting PHASE1/PHASE2
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Sep 2024 — Oct 2024 [monthly]
Recruiting PHASE1/PHASE2
Status: Not Yet Recruiting → Recruiting
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Jul 2024 — Sep 2024 [monthly]
Not Yet Recruiting PHASE1/PHASE2
First recorded
Eligibility Summary
This is a phase 1/2, multicenter, open-label umbrella platform study that will evaluate the safety and tolerability of investigational agents with pembrolizumab and fluoropyrimidine chemotherapy for the first-line (1L) treatment of participants with locally advanced unresectable or metastatic human epidermal growth factor receptor 2 (HER2)-negative gastric, gastroesophageal junction, or esophageal adenocarcinoma. This substudy will have two phases: a safety lead-in phase and an efficacy phase. The safety lead-in phase will be used to evaluate the safety and tolerability, and to establish a recommended Phase 2 dose (RP2D) for investigational agents in combination with chemotherapy and immunotherapy. There is no formal hypothesis in this study.
Contact Information
- Merck Sharp & Dohme LLC
For direct contact, visit the study record on ClinicalTrials.gov .
Study Locations
Antofagasta, Chile , Bangkoknoi, Thailand , Beijing, China , Brest, France , Chur, Switzerland , Dresden, Germany , Düsseldorf, Germany , East Syracuse, United States , Fuzhou, China , Geneva, Switzerland and 40 more locations