A Clinical Study of MK-3120 in People With Bladder Cancer (MK-3120-003)

Phase 1/2 Study of Intravesical MK-3120 in BCG-Naïve or BCG-Exposed High-Risk Non-muscle Invasive Bladder Cancer

Researchers are looking for new ways to treat high-risk non-muscle invasive bladder cancer (HR NMIBC). NMIBC is cancer in the tissue that lines the inside of the bladder and has not spread to the bladder muscle or outside of the bladder. In standard treatment for HR NMIBC, doctors first remove the tumor with a procedure called transurethral resection of the bladder tumor (TURBT). Researchers want to learn if using MK-3120, the study medicine, can treat HR NMIBC after TURBT. The goal of this study is to learn about the safety of MK-3120 and if people tolerate it.

Study Overview

• Status: Recruiting
• Conditions: Urinary Bladder Neoplasms; Bladder Cancer
• Intervention / Treatment: Biological: MK-3120

• Study Type: Interventional
• Enrollment (Estimated): 45
• Phase: Phase 2; Phase 1

Contacts and Locations

• Study Contact: Name: Toll Free Number; Phone Number: 1-888-577-8839; Email: Trialsites@msd.com

Study Locations

• Austria
  • State of Vienna
    • Vienna, State of Vienna, Austria, 1090
      • Recruiting
      • Medizinische Universität Wien ( Site 0021)
      • Contact: Study Coordinator; Phone Number: +4367761942300
• Belgium
  • Oost-Vlaanderen
    • Ghent, Oost-Vlaanderen, Belgium, 9000
      • Recruiting
      • UZ Gent ( Site 0031)
      • Contact: Study Coordinator; Phone Number: +32 9 332 21 11
• Canada
  • Quebec
    • Québec, Quebec, Canada, G1J 1Z4
      • Recruiting
      • CHU de Quebec - Hopital de l'Enfant-Jesus ( Site 0011)
      • Contact: Study Coordinator; Phone Number: 418-525-4444
• France
  • Val-de-Marne
    • Villejuif, Val-de-Marne, France, 94800
      • Recruiting
      • Gustave Roussy ( Site 0041)
      • Contact: Study Coordinator; Phone Number: +33142115348
• Greece
  • Thessaloniki, Greece, 570 01
    • Recruiting
    • European Interbalkan Medical Center ( Site 0051)
    • Contact: Study Coordinator; Phone Number: +302310400213
• Israel
  • Petah Tikva, Israel, 4941492
    • Recruiting
    • Rabin Medical Center ( Site 0062)
    • Contact: Study Coordinator; Phone Number: +97239377377
• Italy
  • Veneto
    • Verona, Veneto, Italy, 37134
      • Recruiting
      • Centro Ricerche Cliniche di Verona ( Site 0072)
      • Contact: Study Coordinator; Phone Number: +390458126564
• Netherlands
  • North Holland
    • Amsterdam, North Holland, Netherlands, 1066 CX
      • Recruiting
      • Nederlands Kanker Instituut Antoni van Leeuwenhoek (NKI AVL) ( Site 0081)
      • Contact: Study Coordinator; Phone Number: +31205129111
• Norway
  • Akershus
    • Lorenskog, Akershus, Norway, 1478
      • Recruiting
      • Akershus Universitetssykehus ( Site 0091)
      • Contact: Study Coordinator; Phone Number: +4767960000
• Spain
  • Andalusia
    • Málaga, Andalusia, Spain, 29010
      • Recruiting
      • Hospital Universitario Virgen de la Victoria ( Site 0111)
      • Contact: Study Coordinator; Phone Number: +34 951 032 095
  • Madrid, Comunidad de
    • Madrid, Madrid, Comunidad de, Spain, 28041
      • Recruiting
      • Hospital Universitario 12 de Octubre ( Site 0112)
      • Contact: Study Coordinator; Phone Number: +34913908121
• Turkey (Türkiye)
  • Ankara, Turkey (Türkiye), 06620
    • Recruiting
    • Ankara University Health Practice and Research Hospitals ( Site 0132)
    • Contact: Study Coordinator; Phone Number: +90 312 595 71 12
• United States
  • California
    • Bakersfield, California, United States, 93301
      • Recruiting
      • Michael G Oefelein Clinical Trials ( Site 0005)
      • Contact: Study Coordinator; Phone Number: 661-310-1063
  • South Carolina
    • Myrtle Beach, South Carolina, United States, 29572
      • Recruiting
      • Carolina Urologic Research Center ( Site 0006)
      • Contact: Study Coordinator; Phone Number: 843-449-1010

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Has histologically confirmed carcinoma in situ (CIS) +/- papillary high-risk non-muscle invasive bladder cancer (NMIBC), confirmed locally.
• Is an individual whose most recent transurethral resection of bladder tumor (TURBT) was performed within 12 weeks before allocation and showed high-risk NMIBC histology. For individuals with papillary tumors (Ta and T1), a complete TURBT must have been performed, as characterized by attainment of a visually complete resection of all papillary tumors (Ta and T1).
• Is either: a) Bacillus Calmette-Guérin (BCG)-naïve, defined as either having never received BCG or having received BCG more than 2 years before CIS +/- papillary high-risk NMIBC recurrence. Recurrence must be at least 24 months from the last exposure to BCG with evidence of complete response during the 2-year period post-BCG OR; b) BCG-exposed and received adequate BCG therapy and had recurrence of CIS +/- papillary high-risk NMIBC >12 months but ≤24 months after the last BCG dose.
• Human immunodeficiency virus (HIV)-infected participants must have well-controlled HIV on antiretroviral therapy.
• Participants who are hepatitis B surface antigen positive are eligible if they have received hepatitis B virus (HBV) antiviral therapy for at least 4 weeks, and have undetectable HBV viral load prior to allocation.
• Participants with history of hepatitis C virus (HCV) infection are eligible if HCV viral load is undetectable at screening.

Exclusion Criteria:

• Has history of or current locally advanced (ie, T2, T3, T4) or metastatic urothelial cancer (UC).
• Has concurrent extravesical (ie, urethra, ureter, renal pelvis) non-muscle invasive UC or history of extravesical non-muscle invasive UC that recurred within the last 2 years.
• Has active total bladder incontinence, active urinary tract infection, neurogenic bladder, or urethral stricture.
• Has a condition that would prohibit normal voiding (or holding bladder voiding for 1 to 2 hours).
• Has uncontrolled, significant cardiovascular disease or cerebrovascular disease, including New York Heart Association Class III or IV congestive heart failure, unstable angina, myocardial infarction, uncontrolled symptomatic arrhythmia, prolongation of QTcF interval to >470 ms, and/or other serious cardiovascular and cerebrovascular diseases within the 6 months preceding study intervention.
• Has history of documented severe dry eye syndrome, severe Meibomian gland disease and/or blepharitis, or severe corneal disease that prevents/delays corneal healing.
• HIV-infected participants with a history of Kaposi's sarcoma and/or Multicentric Castleman's Disease.
• Has known additional malignancy that is progressing or has required active treatment within the past 3 years.
• Has known active central nervous system metastases and/or carcinomatous meningitis.
• Has active infection requiring systemic therapy.
• Has a history of (noninfectious) pneumonitis/interstitial lung disease (ILD) that required steroids, or has current pneumonitis/ILD.
• Has not adequately recovered from major surgery or has ongoing surgical complications.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: MK-3120; Participants will be administered MK-3120 once weekly for the first 6 weeks, followed by once monthly for 9 months.	Biological: MK-3120; Intravesical administration at one of three doses per protocol; Other Names: SKB410

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Number of Participants Who Experience a Dose-limiting Toxicity (DLT)	Any of the following toxicities will be considered a DLT: Hematuria leading to clot or obstruction; Grade (Gr) 4 thrombocytopenia; Gr 3 thrombocytopenia associated with clinically significant bleeding; Febrile neutropenia for more than 1 hour; Other Gr ≥3 hematologic toxicity lasting >7 days; Nonhematologic AE ≥Gr 3 (with exceptions); ≥Gr 2 pneumonitis/ interstitial lung disease; Any ≥Gr 3 nonhematologic laboratory value if clinically significant medical intervention is required, leads to hospitalization, persists for >7 days, results in a drug induced liver injury, or elevated aspartate aminotransferase (AST) or alanine aminotransferase (ALT) lab value >8 ×upper limit of normal (ULN) regardless of duration and AST or ALT elevation 5 × to 8 × ULN that persists for greater than 2 weeks; Recurrent Gr 2 AE resulting in >2 weeks delay in receiving the next treatment dose; Any intervention-related toxicity that results in study intervention discontinuation; Gr 5 toxicity or AE.	Up to approximately 5 weeks
Number of Participants Who Experience One or More Adverse Events (AEs)	An AE is defined as any unfavorable and unintended sign, symptom, disease, or worsening of preexisting condition temporally associated with study treatment and irrespective of causality to study treatment.	Up to approximately 24 months
Number of Participants Who Discontinue Study Treatment Due to AEs	An AE is defined as any unfavorable and unintended sign, symptom, disease, or worsening of preexisting condition temporally associated with study treatment and irrespective of causality to study treatment.	Up to approximately 12 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Complete Response Rate (CRR)	CR is defined as the absence of all of the following as determined by local assessment using urine cytology, cystoscopy, biopsy and radiology assessments as applicable: High-risk non-muscle invasive urothelial cancer (UC) (defined as high-grade [HG] noninvasive papillary [Ta], carcinoma in situ [CIS], or any submucosal invasive [T1] disease of the bladder, urethra, or upper tract [ureters, renal pelvis]); Any muscle invasive tumor (T2) or greater in the bladder, including transurethral prostate stromal invasion of UC, or in the upper tract (ureters, renal pelvis); Metastatic UC, defined as:Regional lymph node metastasis of UC (N1 or greater)Distant lymph node or visceral metastasis of UC (M1)	Up to approximately 3 months

Collaborators and Investigators

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

Publications and helpful links

Helpful Links

• Merck Clinical Trials Information
• Plain Language Summary

Study record dates

Study Major Dates

• Study Start (Actual): December 9, 2025
• Primary Completion (Estimated): February 28, 2029
• Study Completion (Estimated): February 28, 2029

Study Registration Dates

• First Submitted: October 27, 2025
• First Submitted That Met QC Criteria: October 27, 2025
• First Posted (Actual): October 30, 2025

Study Record Updates

• Last Update Posted (Actual): April 23, 2026
• Last Update Submitted That Met QC Criteria: April 22, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Urogenital Diseases; Urogenital Neoplasms; Neoplasms by Site; Neoplasms; Male Urogenital Diseases; Urologic Diseases; Female Urogenital Diseases; Female Urogenital Diseases and Pregnancy Complications; Urologic Neoplasms; Urinary Bladder Diseases; Urinary Bladder Neoplasms
• Other Study ID Numbers: 3120-003; U1111-1317-2687 (Registry Identifier: UTN); 2025-520467-40-00 (Registry Identifier: EU CT); MK-3120-003 (Other Identifier: MSD)

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