NCT04634877|Active Not RecruitingPhase 3DMCFDA Drug

Study of Pembrolizumab (MK-3475) in Combination With Adjuvant Chemotherapy With or Without Radiotherapy in Participants With Newly Diagnosed Endometrial Cancer After Surgery With Curative Intent (MK-3475-B21 / KEYNOTE-B21 / ENGOT-en11 / GOG-3053)

A Phase 3, Randomized, Double-Blind Study of Pembrolizumab Versus Placebo in Combination With Adjuvant Chemotherapy With or Without Radiotherapy for the Treatment of Newly Diagnosed High-Risk Endometrial Cancer After Surgery With Curative Intent (KEYNOTE-B21 / ENGOT-en11 / GOG-3053)

Merck Sharp & Dohme LLC ClinicalTrials.gov

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8 other identifiers

3475-B21KEYNOTE-B21ENGOT-en11GOG-3053jRCT20312003992022-501973-37-00U1111-1282-64302020-003424-17

Study Type

interventional

Target

990

Locations

28 countries

Sites

231

Timeline

RegisteredNov 2020

StartedJan 2021

CompletionSep 2026

Brief Summary

The purpose of this study is to compare pembrolizumab + adjuvant chemotherapy with placebo + adjuvant chemotherapy, with or without radiotherapy, with respect to disease-free survival (DFS) as assessed radiographically by the investigator or by histopathologic confirmation of suspected disease recurrence, and with respect to overall survival (OS). The primary hypotheses are that pembrolizumab + adjuvant chemotherapy is superior to placebo + adjuvant chemotherapy, with or without radiotherapy, with respect to DFS as assessed radiographically by the investigator or by histopathologic confirmation of suspected disease recurrence, and with respect to OS.

Trial Health

On Track

Trial Health Score

Automated assessment based on enrollment pace, timeline, and geographic reach

Strong global presence with extensive site network

Enrollment

990

participants targeted

Target at P75+ for phase_3

Timeline

4mo left

Started Jan 2021

Longer than P75 for phase_3

Geographic Reach

28 countries

231 active sites

Status

active not recruiting

Health score is calculated from publicly available data and should be used for screening purposes only.

Trial Relationships

Click on a node to explore related trials.

Study Timeline

Key milestones and dates

5.7 years study duration

Study Progress94%

Jan 2021Sep 2026

First Submitted

Initial submission to the registry

November 12, 2020

Completed

6 days until next milestone

First Posted

Study publicly available on registry

November 18, 2020

Completed

2 months until next milestone

Study Start

First participant enrolled

January 10, 2021

Completed

5.7 years until next milestone

Primary Completion

Last participant's last visit for primary outcome

September 15, 2026

Expected

Same day until next milestone

Study Completion

Last participant's last visit for all outcomes

September 15, 2026

Last Updated

June 9, 2025

Status Verified

May 1, 2025

Enrollment Period

5.7 years

First QC Date

November 12, 2020

Last Update Submit

June 5, 2025

Conditions

Endometrial Neoplasms

Keywords

Programmed Cell Death-1 (PD1, PD-1)Programmed Death-Ligand 1 (PDL1, PD-L1)Programmed Cell Death 1 Ligand 2 (PDL2, PD-L2 )

Outcome Measures

Primary Outcomes (2)

Disease-Free Survival (DFS) as Assessed Radiographically by Investigator or by Histopathologic Confirmation of Suspected Disease Recurrence
DFS is defined as the time from randomization to the first documented local recurrence, distant metastasis, secondary systemic malignancy, or death due to any cause, whichever occurs first. The DFS as assessed radiographically by investigator or by histopathologic confirmation of suspected disease recurrence, will be presented.
Up to approximately 42 months
Overall Survival (OS)
OS is defined as the time from randomization to death due to any cause.
Up to approximately 54 months

Secondary Outcomes (10)

Disease-Free Survival (DFS) as Assessed Radiographically by Blinded Independent Central Review (BICR) or by Histopathologic Confirmation of Suspected Disease Recurrence
Up to approximately 42 months
Disease-Free Survival (DFS) as Assessed Radiographically by Investigator or by Histopathologic Confirmation of Suspected Disease Recurrence by Combined Positivity Score (CPS)-Determined Programmed Cell Death 1 Ligand 1 (PD-L1) Status
Up to approximately 42 months
Overall Survival (OS) as Assessed Radiographically by Investigator or by Histopathologic Confirmation of Suspected Disease Recurrence by Combined Positivity Score (CPS)-Determined Programmed Cell Death 1 Ligand 1 (PD-L1) Status
Up to approximately 54 months
Disease-Free Survival (DFS) as Assessed Radiographically by Investigator or by Histopathologic Confirmation of Suspected Disease Recurrence by Tumor Mutation Burden (TMB) Status
Up to approximately 42 months
Overall Survival (OS) as Assessed Radiographically by Investigator or by Histopathologic Confirmation of Suspected Disease Recurrence by Tumor Mutation Burden (TMB) Status
Up to approximately 54 months
+5 more secondary outcomes

Study Arms (2)

Pembrolizumab + Chemotherapy

EXPERIMENTAL

Participants receive pembrolizumab 200 mg intravenously (IV) on Day 1 of each 3-week cycle (Q3W) for 6 cycles followed by pembrolizumab 400 mg IV on Day 1 of each 6-week cycle (Q6W) for an additional 6 cycles. During the Q3W dosing period of pembrolizumab, participants receive concurrent standard of care (SoC) chemotherapy for 4 or 6 cycles. Participants optionally receive radiotherapy starting within 6 weeks of completion of SoC chemotherapy. The SoC chemotherapy regimen includes carboplatin AUC 5 or 6 IV Q3W plus paclitaxel 175 mg/m\^2 IV Q3W. In the event of severe hypersensitivity to, or an AE requiring discontinuation of, carboplatin or paclitaxel, cisplatin or docetaxel may be substituted after investigator consults with sponsor. The SoC radiotherapy regimen may include, at the discretion of the investigator, external beam radiotherapy (EBRT) ≥4500 cGY with variable dose frequency, with or without cisplatin 50 mg/m\^2 IV on days 1 and 29 of EBRT, and/or brachytherapy radiation.

Biological: PembrolizumabDrug: CarboplatinDrug: PaclitaxelDrug: DocetaxelDrug: CisplatinRadiation: External Beam Radiotherapy (EBRT)Drug: Cisplatin (as radiosensitizer)Radiation: Brachytherapy

Placebo + Chemotherapy

PLACEBO COMPARATOR

Participants receive placebo to pembrolizumab intravenously (IV) on Day 1 of each 3-week cycle (Q3W) for 6 cycles followed by placebo IV on Day 1 of each 6-week cycle (Q6W) for an additional 6 cycles. During the Q3W dosing period of placebo, participants receive concurrent standard of care (SoC) chemotherapy for 4 or 6 cycles. Participants optionally receive radiotherapy starting within 6 weeks of completion of SoC chemotherapy. The SoC chemotherapy regimen includes carboplatin AUC 5 or 6 IV Q3W plus paclitaxel 175 mg/m\^2 IV Q3W. In the event of severe hypersensitivity to, or an AE requiring discontinuation of, carboplatin or paclitaxel, cisplatin or docetaxel may be substituted after investigator consults with sponsor. The SoC radiotherapy regimen may include, at the discretion of the investigator, external beam radiotherapy (EBRT) ≥4500 cGY with variable dose frequency, with or without cisplatin 50 mg/m\^2 IV on days 1 and 29 of EBRT, and/or brachytherapy radiation.

Drug: CarboplatinDrug: PaclitaxelDrug: Placebo for pembrolizumabDrug: DocetaxelDrug: CisplatinRadiation: External Beam Radiotherapy (EBRT)Drug: Cisplatin (as radiosensitizer)Radiation: Brachytherapy

Interventions

PembrolizumabBIOLOGICAL

IV infusion

Also known as: KEYTRUDA®, MK-3475

Pembrolizumab + Chemotherapy

CarboplatinDRUG

IV infusion