HomeTrialNCT06469944
NCT06469944Phase 1Phase 2RECRUITING

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)

Study 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.

View on ClinicalTrials.gov ↗
Study Details
Enrollment160 participants
Primary Completion
Lead SponsorMerck Sharp & Dohme LLC
Data Retrieved2026-04-11 02:55:36.205178+00:00
What This Trial Means for Biotech Investors
Trial Phase Context

Phase 1 trials primarily test safety and dosing in a small number of participants (typically 20–100). Results do not yet speak to efficacy. FDA approval is typically many years away from this stage.

Phase 2 trials begin testing efficacy in a larger patient group (100–300). This is often where biotech binary events occur — positive Phase 2 data can significantly advance a company's pipeline narrative, while failures can be terminal for a program.

Status & Expected Data

Currently recruiting: the trial is enrolling patients. A data readout is not expected until after enrollment closes and the follow-up period is complete.

Enrolled: 160 participants
Sponsor Catalyst Profile

Merck & Co (MRK) is the sponsoring company for this trial. BiotechSign currently grades this company F (35/100) based on composite catalyst signals across its full pipeline. This trial is one data point in that overall catalyst picture.

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