A Study of Efficacy and Safety of Pembrolizumab Plus Enfortumab Vedotin (EV) +/- Investigational Agents in First-Line Metastatic Urothelial Carcinoma (mUC) (MK-3475-04B/KEYMAKER-U04)

NCT ID: NCT05845814

Last Updated: 2025-09-10

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

Get a concise snapshot of the trial, including recruitment status, study phase, enrollment targets, and key timeline milestones.

Recruitment Status

ACTIVE_NOT_RECRUITING

Clinical Phase

PHASE1/PHASE2

Total Enrollment

390 participants

Study Classification

INTERVENTIONAL

Study Start Date

2023-06-23

Study Completion Date

2027-05-31

Brief Summary

Review the sponsor-provided synopsis that highlights what the study is about and why it is being conducted.

This study is a substudy being conducted under one pembrolizumab umbrella master study KEYMAKER-U04. The substudy will consist of 2 parts. Part 1 will evaluate the efficacy and safety of coformulated favezelimab/pembrolizumab plus EV and coformulated vibostolimab/pembrolizumab plus EV relative to pembrolizumab plus EV. There will be no comparison of coformulated favezelimab/pembrolizumab plus EV versus coformulated vibostolimab/pembrolizumab plus EV. If ORR and/or DRR are substantially better on coformulated favezelimab/pembrolizumab plus EV and/or coformulated vibostolimab/pembrolizumab plus EV compared with pembrolizumab plus EV, after evaluation of the totality of data, the sponsor might consider Part 2 (expansion) to further characterize the efficacy and safety of the treatment arms under study.

Detailed Description

Dive into the extended narrative that explains the scientific background, objectives, and procedures in greater depth.

The master study for this substudy is MK-3475-U04/KEYMAKER-U04. The master study will not be screening any participants and will not be registered.

With Amendment 2, participants will discontinue treatment with coformulated vibostolimab/pembrolizumab (Arm B) and be transitioned to pembrolizumab only. Per protocol, no analysis of Part 2 primary or secondary outcome measures (including efficacy or safety) will occur since Part 2 of the study will no longer take place.

Conditions

See the medical conditions and disease areas that this research is targeting or investigating.

Metastatic Urothelial Carcinoma Urothelial Neoplasms

Study Design

Understand how the trial is structured, including allocation methods, masking strategies, primary purpose, and other design elements.

Allocation Method

RANDOMIZED

Intervention Model

PARALLEL

In Part 1, participants will be randomized in a 1:1:1 ratio to receive either Arm A (coformulated favezelimab/pembrolizumab plus EV), Arm B (coformulated vibostolimab/pembrolizumab plus EV), or Arm C (pembrolizumab plus EV). If Part 2 is conducted, participants will be randomized in a 1:1:1 ratio to Arms A, B, and C or in a 1:1 ratio to Arms A and C or B and C, depending on the treatment arm(s) that are expanded in Part 2.
Primary Study Purpose

TREATMENT

Blinding Strategy

NONE

Study Groups

Review each arm or cohort in the study, along with the interventions and objectives associated with them.

Arm A: Coformulated favezelimab/pembrolizumab plus EV

Participants will receive coformulated favezelimab/pembrolizumab (800 mg/200 mg) as an intravenous (IV) infusion on Day 1 of every 3-week cycle for up to \~2 years (35 cycles) and EV at 1.25 mg/kg, administered as an IV infusion on Days 1 and 8 of every 3-week cycle until disease progression, intolerable toxicity, or investigator decision.

Group Type EXPERIMENTAL

Coformulated favezelimab/pembrolizumab

Intervention Type BIOLOGICAL

Coformulated favezelimab/pembrolizumab (800 mg/200 mg) IV infusion

EV

Intervention Type COMBINATION_PRODUCT

1.25 mg/kg IV infusion

Arm B: Coformulated vibostolimab/pembrolizumab plus EV

Participants will receive coformulated vibostolimab/pembrolizumab (200 mg/200 mg) as an IV infusion on Day 1 of every 3-week cycle, for up to \~2 years (35 cycles) and EV at 1.25 mg/kg, administered as an IV infusion on Days 1 and 8 of every 3-week cycle until disease progression, intolerable toxicity, or investigator decision.

Group Type EXPERIMENTAL

Coformulated vibostolimab/pembrolizumab

Intervention Type BIOLOGICAL

Coformulated vibostolimab/pembrolizumab (200 mg/200 mg) IV infusion

EV

Intervention Type COMBINATION_PRODUCT

1.25 mg/kg IV infusion

Arm C: Pembrolizumab plus EV

Participants will receive 200 mg pembrolizumab as an IV infusion on Day 1 of every 3-week cycle for up to \~2 years (35 cycles) and EV at 1.25 mg/kg, administered as an IV infusion on Days 1 and 8 of every 3-week cycle, until disease progression, intolerable toxicity, or investigator decision.

Group Type ACTIVE_COMPARATOR

EV

Intervention Type COMBINATION_PRODUCT

1.25 mg/kg IV infusion

Pembrolizumab

Intervention Type BIOLOGICAL

200 mg IV infusion

Interventions

Learn about the drugs, procedures, or behavioral strategies being tested and how they are applied within this trial.

Coformulated favezelimab/pembrolizumab

Coformulated favezelimab/pembrolizumab (800 mg/200 mg) IV infusion

Intervention Type BIOLOGICAL

Coformulated vibostolimab/pembrolizumab

Coformulated vibostolimab/pembrolizumab (200 mg/200 mg) IV infusion

Intervention Type BIOLOGICAL

EV

1.25 mg/kg IV infusion

Intervention Type COMBINATION_PRODUCT

Pembrolizumab

200 mg IV infusion

Intervention Type BIOLOGICAL

Other Intervention Names

Discover alternative or legacy names that may be used to describe the listed interventions across different sources.

MK-4280A MK-7684A Padcev ASG-22CE ASG-22ME MK-3475 KEYTRUDA®

Eligibility Criteria

Check the participation requirements, including inclusion and exclusion rules, age limits, and whether healthy volunteers are accepted.

Inclusion Criteria

* Must have histologically documented, locally advanced/metastatic urothelial carcinoma (la/mUC).

* Participants with mixed histology are eligible provided the urothelial component is ≥50% (and \<10% plasmacytoid component)
* Participants whose tumors contain any neuroendocrine component are not eligible (variant histology to be confirmed locally)
* Must not have received prior systemic therapy for la/mUC. The following therapies in earlier disease setting (eg, muscle-invasive urothelial carcinoma (MIUC)) are permitted:

* Participants that received neoadjuvant or adjuvant chemotherapy are permitted.
* Participants who received anti- programmed cell death 1 protein (PD-1) or programmed cell death ligand 1 (PD-L1) therapy for an earlier disease stage (eg, NMIBC, MIUC) with progression/recurrence \>12 months from completion of therapy are permitted.
* Must provide an archival tumor tissue sample or newly obtained core or excisional biopsy of a tumor lesion demonstrating UC, not previously irradiated, and adequate for biomarker evaluation. A newly obtained biopsy is strongly preferred, but not required if archival tissue is evaluable.
* Any AEs due to previous anticancer therapies must have recovered to ≤Grade 1 or baseline. Endocrine-related AEs adequately treated with hormone replacement or with \<Grade 2 neuropathy are eligible.

Exclusion Criteria

* Has a known additional malignancy, except if the participant has undergone potentially curative therapy with no evidence of that disease recurrence for at least 3 years since initiation of that therapy.
* Central nervous system (CNS) metastases are permitted on-study if all of the following are true: a) CNS metastases have been clinically stable for at least 4 weeks prior to screening and baseline scans show no evidence of new or enlarged metastasis; b) the participant is on a stable dose of ≤10 mg/day of prednisone or equivalent for at least 2 weeks (if requiring steroid treatment); c) participant does not have leptomeningeal disease.
* Has received a live or live-attenuated vaccine within 30 days prior to the first dose of study intervention.
* Has received an investigational agent or has used an investigational device within 4 weeks prior to study intervention administration.
* Has a diagnosis of immunodeficiency or is receiving chronic systemic steroid therapy or any other form of immunosuppressive therapy within 7 days prior the first dose of study intervention. Inhaled or topical steroids are permitted in the absence of active autoimmune disease. Physiologic replacement doses of corticosteroids are permitted for participants with adrenal insufficiency.
* Has active keratitis or corneal ulcerations. Superficial punctate keratitis is allowed if the disorder is being adequately treated in the opinion of the investigator.
* Has an active autoimmune disease that has required systemic treatment in past 2 years except replacement therapy.
* Has a history of uncontrolled diabetes.
* Has a history of (noninfectious) pneumonitis that required steroids or has current pneumonitis
* Has an active infection (viral, bacterial, or fungal) requiring systemic therapy.
* Has a known history of human immunodeficiency virus (HIV) infection.
* Has hepatitis B or hepatitis C virus infection.
* Has had major surgery within 4 weeks prior to first dose of study intervention.
* Has had an allogenic tissue/solid organ transplant
Minimum Eligible Age

18 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

No

Sponsors

Meet the organizations funding or collaborating on the study and learn about their roles.

Merck Sharp & Dohme LLC

INDUSTRY

Sponsor Role lead

Responsible Party

Identify the individual or organization who holds primary responsibility for the study information submitted to regulators.

Responsibility Role SPONSOR

Principal Investigators

Learn about the lead researchers overseeing the trial and their institutional affiliations.

Medical Director

Role: STUDY_DIRECTOR

Merck Sharp & Dohme LLC

Locations

Explore where the study is taking place and check the recruitment status at each participating site.

Moores Cancer Center ( Site 3028)

La Jolla, California, United States

Site Status

University of California, Irvine (UCI) Health - UC Irvine Medical Center ( Site 3045)

Orange, California, United States

Site Status

UCSF Medical Center at Mission Bay ( Site 3044)

San Francisco, California, United States

Site Status

Anschutz Cancer Pavilion ( Site 3017)

Aurora, Colorado, United States

Site Status

Emory University School of Medicine ( Site 3043)

Atlanta, Georgia, United States

Site Status

Indiana University Melvin and Bren Simon Cancer Center ( Site 3011)

Indianapolis, Indiana, United States

Site Status

Dana-Farber Cancer Institute ( Site 3047)

Boston, Massachusetts, United States

Site Status

Siteman Cancer Center ( Site 3038)

St Louis, Missouri, United States

Site Status

Icahn School of Medicine at Mount Sinai ( Site 3018)

New York, New York, United States

Site Status

Memorial Sloan Kettering Cancer Center ( Site 3031)

New York, New York, United States

Site Status

Duke Cancer Institute ( Site 3027)

Durham, North Carolina, United States

Site Status

Cleveland Clinic-Taussig Cancer Center ( Site 3036)

Cleveland, Ohio, United States

Site Status

UPMC Hillman Cancer Center ( Site 3014)

Pittsburgh, Pennsylvania, United States

Site Status

Huntsman Cancer Institute-HCI Clinical Trials Office ( Site 3041)

Salt Lake City, Utah, United States

Site Status

Royal Brisbane and Women's Hospital-Medical Oncology Clinical Trials Unit, Cancer Care Services ( Site 3951)

Brisbane, Queensland, Australia

Site Status

Austin Health-Cancer Clinical Trials Centre ( Site 3950)

Heidelberg, Victoria, Australia

Site Status

The Ottawa Hospital - General Campus-The Ottawa Hospital Cancer Centre ( Site 3105)

Ottawa, Ontario, Canada

Site Status

Sunnybrook Research Institute - Odette Cancer Centre ( Site 3108)

Toronto, Ontario, Canada

Site Status

Princess Margaret Cancer Centre ( Site 3106)

Toronto, Ontario, Canada

Site Status

FALP-UIDO ( Site 3151)

Santiago, Region M. de Santiago, Chile

Site Status

Bradfordhill-Clinical Area ( Site 3155)

Santiago, Region M. de Santiago, Chile

Site Status

ONCOCENTRO APYS-ACEREY ( Site 3158)

Viña del Mar, Región de Valparaíso, Chile

Site Status

Bradford Hill Norte ( Site 3152)

Antofagasta, , Chile

Site Status

CHU de Bordeaux Hop St ANDRE ( Site 3607)

Bordeaux, Aquitaine, France

Site Status

Centre Georges François Leclerc-Centre de recherche clinique ( Site 3608)

Dijon, Cote-d Or, France

Site Status

Oncopole Claudius Regaud ( Site 3610)

Toulouse, Haute-Garonne, France

Site Status

centre hospitalier lyon sud ( Site 3606)

Pierre-Bénite, Rhone, France

Site Status

Hôpital Européen Georges Pompidou ( Site 3605)

Paris, , France

Site Status

Rambam Health Care Campus-Oncology Division ( Site 3501)

Haifa, , Israel

Site Status

Rabin Medical Center-Oncology ( Site 3504)

Petah Tikva, , Israel

Site Status

Sheba Medical Center-ONCOLOGY ( Site 3503)

Ramat Gan, , Israel

Site Status

Istituto Nazionale Tumori IRCCS Fondazione Pascale ( Site 3406)

Napoli, Campania, Italy

Site Status

Fondazione IRCCS Istituto Nazionale dei Tumori-Struttura Complessa Oncologia Medica 1 ( Site 3405)

Milan, Lombardy, Italy

Site Status

Ospedale San Raffaele-Oncologia Medica ( Site 3403)

Milan, , Italy

Site Status

Maastricht UMC+ ( Site 3304)

Maastricht, Limburg, Netherlands

Site Status

Nederlands Kanker Instituut - Antoni van Leeuwenhoek (NKI-AVL)-medical oncology ( Site 3302)

Amsterdam, North Holland, Netherlands

Site Status

Erasmus Medisch Centrum-Medical Oncology ( Site 3303)

Rotterdam, South Holland, Netherlands

Site Status

Severance Hospital, Yonsei University Health System-Medical oncology ( Site 3903)

Seoul, , South Korea

Site Status

Asan Medical Center-Department of Oncology ( Site 3901)

Seoul, , South Korea

Site Status

Samsung Medical Center ( Site 3902)

Seoul, , South Korea

Site Status

Hospital Universitari Vall d'Hebron ( Site 3767)

Barcelona, Catalonia, Spain

Site Status

Hospital Clinico San Carlos ( Site 3765)

Madrid, , Spain

Site Status

Chang Gung Memorial Hospital at Kaohsiung-Oncology and Hematology ( Site 3802)

Kaohsiung City, , Taiwan

Site Status

National Cheng Kung University Hospital-Clinical Trial Center ( Site 3803)

Tainan City, , Taiwan

Site Status

National Taiwan University Hospital-Oncology ( Site 3801)

Taipei, , Taiwan

Site Status

St Bartholomew's Hospital-Centre for Experimental Cancer Medicine ( Site 3206)

London, London, City of, United Kingdom

Site Status

ROYAL MARSDEN HOSPITAL (CHELSEA) ( Site 3201)

London, London, City of, United Kingdom

Site Status

Countries

Review the countries where the study has at least one active or historical site.

United States Australia Canada Chile France Israel Italy Netherlands South Korea Spain Taiwan United Kingdom

Related Links

Access external resources that provide additional context or updates about the study.

Other Identifiers

Review additional registry numbers or institutional identifiers associated with this trial.

MK-3475-04B

Identifier Type: OTHER

Identifier Source: secondary_id

2023-506385-30-00

Identifier Type: REGISTRY

Identifier Source: secondary_id

U1111-1293-7564

Identifier Type: REGISTRY

Identifier Source: secondary_id

2022-001371-14

Identifier Type: EUDRACT_NUMBER

Identifier Source: secondary_id

3475-04B

Identifier Type: -

Identifier Source: org_study_id

More Related Trials

Additional clinical trials that may be relevant based on similarity analysis.

Sacituzumab Govitecan Plus EV in Metastatic UC
NCT04724018 RECRUITING PHASE1/PHASE2