Study of Pembrolizumab (MK-3475) Versus Placebo After Complete Resection of High-Risk Stage III Melanoma (MK-3475-054/1325-MG/KEYNOTE-054)

February 19, 2026 updated by: Merck Sharp & Dohme LLC

Adjuvant Immunotherapy With Anti-PD-1 Monoclonal Antibody Pembrolizumab (MK-3475) Versus Placebo After Complete Resection of High-risk Stage III Melanoma: A Randomized, Double- Blind Phase 3 Trial of the EORTC Melanoma Group

This study will assess whether post-surgery therapy with pembrolizumab improves recurrence-free survival (RFS) as compared to placebo for high-risk participants with melanoma (Stage IIIA [> 1 mm metastasis], IIIB and IIIC). The study will also assess whether pembrolizumab improves RFS versus placebo in the subgroup of participants with programmed cell death-ligand 1 (PD-L1)-positive tumor expression. Participants will be stratified for stage of disease and region and then will be randomly assigned to receive either pembrolizumab or placebo as post-surgery therapy in Part 1. In Part 2, participants who experience a disease recurrence are eligible for pembrolizumab treatment (if treated with placebo in Part 1) or pembrolizumab rechallenge (if treated with pembrolizumab in Part 1).

Study Overview

Status

Active, not recruiting

Conditions

Intervention / Treatment

Detailed Description

As of Amendment 8, enrollment in Part 2 has closed, and an optional pembrolizumab extension study will not be available to participants after study closure.

Study Type

Interventional

Enrollment (Actual)

1019

Phase

  • Phase 3

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Description

Inclusion criteria:

  • Completely resected Stage III melanoma
  • Tumor tissue available for evaluation of PD-L1 expression
  • Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1
  • Adequate organ function
  • No prior therapy for melanoma except surgery for primary melanoma lesions (or previously treated with interferon for thick primary melanomas without evidence of lymph node involvement are eligible)
  • Female participants of childbearing potential should be willing to use adequate methods of birth control or be surgically sterile, or abstain from heterosexual activity for the course of the study through 120 days after the last dose of study medication
  • Male participants should agree to use an adequate method of birth control starting with the first dose of study therapy through 120 days after the last dose of study medication

Exclusion criteria:

  • Mucosal or ocular melanoma
  • History of (non-infectious) pneumonitis that required steroids or current pneumonitis
  • History of or current interstitial lung disease
  • History of hematologic or primary solid tumor malignancy, unless no evidence of that disease for 5 years
  • Active autoimmune disease that has required systemic treatment in past 2 years
  • Active infection requiring therapy
  • Unstable hyperthyroidism or hypothyroidism
  • Diagnosis of immunodeficiency
  • Systemic steroid therapy or any other form of immunosuppressive therapy within 7 days prior to the first dose of study medication
  • Known history of human immunodeficiency virus (HIV), active Hepatitis B or C
  • Treatment with live vaccine within 30 days prior to the first dose of study medication are not eligible
  • Prior treatment with any anti-cytotoxic T-lymphocyte-associated protein 4 (CTLA4) monoclonal antibody or anti-programmed cell death receptor 1 (PD-1), anti-programmed cell death receptor ligand 1 (PD-L1), or anti-programmed cell death receptor ligand 2 (PD-L2) agent, or prior participation in any Merck pembrolizumab clinical trial
  • Currently participating and receiving study therapy, or participated in a study of an investigational agent and received study therapy or used an investigation device within 4 weeks of the first dose of study medication
  • Pregnant or breastfeeding, or expecting to conceive or father children within the projected duration of the trial, starting with the screening visit through 120 days after the last dose of study medication
  • Participant is or has an immediate family member (e.g., spouse, parent/legal guardian, sibling or child) who is investigational site or Sponsor staff directly involved with this trial without prospective Institutional Review Board approval (by chair or designee) is given

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Pembrolizumab
In Part 1, participants receive pembrolizumab 200 mg intravenously (IV) as post-surgery therapy every 3 weeks (Q3W) for up to 1 year. During Part 2, participants with documented recurrence may receive optional re-treatment with pembrolizumab Q3W for up to 2 years or disease progression.
Biological: pembrolizumab
Pembrolizumab 200 mg administered intravenously (IV) on Day 1 of each 21-day cycle
Other Names:
  • MK-3475
  • SCH 900475
  • KEYTRUDA®
Placebo Comparator: Placebo
In Part 1, participants receive placebo IV as post-surgery therapy Q3W. During Part 2, participants with documented recurrence who received placebo in Part 1 may receive optional treatment with pembrolizumab Q3W for up to 2 years or disease progression.
Drug: placebo
Normal saline solution administered IV on Day 1 of each 21-day cycle

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Part 1: Percentage of Participants With Recurrence-Free Survival (RFS) At 6 Months Among All Participants
Time Frame: 6 months
RFS was defined as the time between the date of randomization and the date of first melanoma recurrence (local, regional, distant metastasis) or death (whatever the cause), whichever occurred first. For participants who remained alive and whose disease had not recurred, RFS was censored on the date of last visit/contact with disease assessments. The percentage of participants with RFS at Month 6 was reported for all participants in both treatment arms of Part 1.
6 months
Part 1: Percentage of Participants With Recurrence-Free Survival (RFS) At 6 Months Among Participants With PD-L1-positive Tumor Expression
Time Frame: 6 months
RFS was defined as the time between the date of randomization and the date of first melanoma recurrence (local, regional, distant metastasis) or death (whatever the cause), whichever occurred first. For participants who remained alive and whose disease had not recurred, RFS was censored on the date of last visit/contact with disease assessments. The percentage of participants with RFS at Month 6 was reported for all participants with PD-L1-positive tumors in both treatment arms of Part 1.
6 months

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Number of Participants Who Experienced At Least 1 Adverse Event (AE)
Time Frame: Up to 22 months
An AE is defined as "any untoward medical occurrence in a participant which does not necessarily have to have a causal relationship with this treatment". An AE can therefore be any unfavorable and unintended signs (such as rash or enlarged liver), symptoms (such as nausea or chest pain), an abnormal laboratory finding (including results of blood tests, x-rays or scans) or a disease temporarily associated with the use of the protocol treatment, whether or not considered related to the investigational medicinal product. The number of participants who experienced at least 1 AE was reported for all participants in each treatment arm.
Up to 22 months
Number of Participants Who Discontinued Study Treatment Due to an Adverse Event (AE)
Time Frame: Up to 22 months
An AE is defined as "any untoward medical occurrence in a participant which does not necessarily have to have a causal relationship with this treatment". An AE can therefore be any unfavorable and unintended signs (such as rash or enlarged liver), symptoms (such as nausea or chest pain), an abnormal laboratory finding (including results of blood tests, x-rays or scans) or a disease temporarily associated with the use of the protocol treatment, whether or not considered related to the investigational medicinal product. The number of participants who discontinued study treatment due to an AE was reported for all participants in each treatment arm.
Up to 22 months
Clearance (CL) of Pembrolizumab
Time Frame: Pre-dose on Day 1 of Cycles 1, 2, 4, 6, and 8, and then Day 1 of cycle for every 4 cycles afterwards (up to approximately 16 months). Each cycle is 3 weeks.
Blood samples were to be collected at pre-specified time points and plasma isolated for analysis of pembrolizumab CL, defined as the volume of plasma from which pembrolizumab is eliminated per unit time following IV pembrolizumab administration. Samples were not collected and this analysis was not performed.
Pre-dose on Day 1 of Cycles 1, 2, 4, 6, and 8, and then Day 1 of cycle for every 4 cycles afterwards (up to approximately 16 months). Each cycle is 3 weeks.
Volume of Distribution (V) of Pembrolizumab
Time Frame: Pre-dose on Day 1 of Cycles 1, 2, 4, 6, and 8, and then Day 1 of cycle for every 4 cycles afterwards (up to approximately 16 months). Each cycle is 3 weeks.
Blood samples were to be collected at pre-specified time points and plasma isolated for analysis of pembrolizumab V, defined as the theoretical volume that would be necessary to contain the total amount of administered pembrolizumab at the same concentration that it is observed in the blood plasma. Samples were not collected and this analysis was not performed.
Pre-dose on Day 1 of Cycles 1, 2, 4, 6, and 8, and then Day 1 of cycle for every 4 cycles afterwards (up to approximately 16 months). Each cycle is 3 weeks.
Number of Participants Positive for Anti-Drug Antibodies (ADA) After Pembrolizumab Treatment
Time Frame: Pre-dose on Day 1 of Cycles 1, 2, 4, 6, and 8, and then Day 1 of cycle for every 4 cycles afterwards (up to approximately 16 months). Each cycle is 3 weeks.
Pre- and post-baseline serum samples from participants treated with pembrolizumab were analyzed for ADA by means of a neutralizing antibody assay which assessed the ability of ADA to block (neutralize) binding of pembrolizumab to Programmed Cell Death-1 (PD-1) protein. Overall immunogenicity was defined as the number of treatment emergent positive participants based on the total number of evaluable participants (treatment emergent positive, non-treatment emergent positive and negative immunogenicity status).
Pre-dose on Day 1 of Cycles 1, 2, 4, 6, and 8, and then Day 1 of cycle for every 4 cycles afterwards (up to approximately 16 months). Each cycle is 3 weeks.
Distant Metastases-free Survival (DMFS) in All Participants
Time Frame: Up to approximately 11 years
DMFS will be defined as the time between the date of randomization and the date of first distant metastasis or date of death (whatever the cause), whichever occurs first. For participants who remain alive and distant metastasis-free, DMFS will be censored on the date of last visit/contact with disease assessments. The percentage of participants with DMFS will be reported for all participants in both treatment arms.
Up to approximately 11 years
Distant Metastases-free Survival (DMFS) for Participants With PD-L1-positive Tumor Expression
Time Frame: Up to approximately 11 years

Description:

DMFS will be defined as the time between the date of randomization and the date of first distant metastasis or date of death (whatever the cause), whichever occurs first. For participants who remain alive and distant metastasis-free, DMFS will be censored on the date of last visit/contact with disease assessments. The percentage of participants with DMFS will be reported for all participants with PD-L1-positive tumors in both treatment arms.
Up to approximately 11 years
Overall Survival (OS) for All Participants
Time Frame: Up to approximately 11 years
OS will be defined as the time from the date of randomization to the date of death, whatever the cause. The follow-up of participants still alive will be censored at the moment of last visit/contact. OS will be reported for all participants in both treatment arms.
Up to approximately 11 years
Overall Survival (OS) for Participants With PD-L1-positive Tumor Expression
Time Frame: Up to approximately 11 years
OS will be defined as the time from the date of randomization to the date of death, whatever the cause. The follow-up of participants still alive will be censored at the moment of last visit/contact. OS will be reported for all participants with PD-L1-positive tumors in both treatment arms.
Up to approximately 11 years

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Merck Sharp & Dohme LLC

Collaborators

European Organisation for Research and Treatment of Cancer

Investigators

  • Study Director: Medical Director, Merck Sharp & Dohme LLC

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Helpful Links

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

July 16, 2015

Primary Completion (Actual)

January 8, 2018

Study Completion (Estimated)

November 1, 2026

Study Registration Dates

First Submitted

February 9, 2015

First Submitted That Met QC Criteria

February 9, 2015

First Posted (Estimated)

February 13, 2015

Study Record Updates

Last Update Posted (Actual)

March 5, 2026

Last Update Submitted That Met QC Criteria

February 19, 2026

Last Verified

February 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 3475-054
  • 1325-MG (Other Identifier: European Organisation for Research and Treatment of Cancer)
  • 2014-004944-37 (EudraCT Number)
  • 163277 (Registry Identifier: JAPIC-CTI)
  • KEYNOTE-054 (Other Identifier: MSD)
  • MK-3475-054 (Other Identifier: MSD)
  • 2023-509136-25-00 (Registry Identifier: EU CT)
  • U1111-1309-6016 (Registry Identifier: UTN)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

https://trialstransparency.msdclinicaltrials.com/pdf/ProcedureAccessClinicalTrialData.pdf

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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