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Study of MK-3120 for patients with high-risk non-muscle invasive bladder cancer who have not received or have received BCG treatment

Verified siteInvestigationalNo placebo
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What is this trial about?

A plain-language summary of the goals, design and what participants do

This study is looking at a treatment for high-risk non-muscle invasive bladder cancer with a specific type called carcinoma in situ, which may occur with or without growths called papillary tumors. Non-muscle invasive bladder cancer means the cancer is present in the bladder lining but has not grown into the deeper muscle layer of the bladder wall. Carcinoma in situ is a flat form of cancer that stays in the inner layer of the bladder. The treatment being tested is called MK-3120, which is given directly into the bladder through a procedure called intravesical administration, meaning the medicine is placed inside the bladder rather than taken by mouth or injection into the bloodstream. The medicine is in the form of a suspension, which is a liquid mixture.

The purpose of this study is to evaluate the safety and tolerability of MK-3120 when used alone as a treatment. The study will look at how well people can handle the treatment and what side effects might occur. The study is divided into phases, with the first phase focusing on finding the right dose and understanding safety, while the second phase will look more closely at how well the treatment works. People taking part in this study will either have never received a treatment called BCG (Bacillus Calmette-Guérin), which is a common bladder cancer treatment, or they will have received BCG in the past but their cancer has returned. The study will track whether participants experience dose-limiting toxicity, which means side effects serious enough to require stopping or reducing the treatment dose, and will count how many people have adverse events or need to stop treatment because of side effects.

During the study, participants will receive MK-3120 directly into their bladder at scheduled times. The study will also measure the complete response rate, which means how many people have their cancer completely disappear after treatment. Before joining the study, participants must have had a procedure called transurethral resection of bladder tumor, which is a surgery to remove bladder tumors through the urethra, performed within a certain timeframe. The study will continue for several years to follow participants and gather information about the long-term effects of the treatment.

The research process

The trial runs in 5 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Initial treatment preparation

    After joining the study, your bladder tumor removal procedure must have been completed within the past 12 weeks. This procedure is called a transurethral resection of bladder tumor, which is a surgery to remove tumors from the bladder through the urethra.

    If papillary tumors were present, all visible tumors must have been completely removed during this procedure.

  2. Step 2

    Treatment with MK-3120

    The treatment involves MK-3120, which is an experimental medication containing the active substance skb410.

    The medication is administered directly into the bladder through a catheter. This method is called intravesical administration, which means the medication is placed inside the bladder rather than taken by mouth or injection into the bloodstream.

    The medication is in the form of a liquid suspension that remains in the bladder for a specified period.

  3. Step 3

    Treatment schedule and monitoring

    The study will determine the appropriate dose of MK-3120 for treatment. The specific dosage, frequency, and duration of treatment will be established during the course of the study.

    During treatment, monitoring will occur to assess how the body responds to the medication and to identify any side effects.

    The study is designed to evaluate both the safety of the treatment and whether it helps achieve a complete response, which means the complete disappearance of cancer cells in the bladder.

  4. Step 4

    Safety assessments

    Throughout the study, regular assessments will be conducted to monitor for any adverse events, which are unwanted or harmful reactions that may occur during treatment.

    Special attention will be given to identifying any dose-limiting toxicity, which refers to serious side effects that may require adjustment of the treatment dose.

    If significant side effects occur, treatment may be modified or discontinued based on the assessment of the medical team.

  5. Step 5

    Study duration

    The overall study is expected to continue until February 2029.

    Individual participation duration will depend on how the treatment progresses and the specific treatment schedule assigned during the study.

Who can join the trial?

6 criteria

  • You must have carcinoma in situ (a type of early cancer that stays in the inner lining of the bladder) with or without other tumors growing in a finger-like shape, confirmed by examining tissue under a microscope
  • You must have had a transurethral resection of bladder tumor (a surgical procedure to remove bladder tumors through the urethra) within the last 12 weeks before joining the study. If you had finger-like shaped tumors, all visible tumors must have been completely removed during this surgery
  • You must be in one of these two groups: a) You either never received BCG treatment (a type of bladder cancer therapy using a weakened bacteria) or you received BCG more than 2 years ago before your cancer came back, and you had at least 24 months without cancer after BCG treatment OR b) You received adequate BCG treatment and your cancer came back more than 12 months but less than 24 months after your last BCG dose
  • If you have HIV infection (a virus that affects the immune system), your condition must be well-controlled with medications
  • If you have hepatitis B (a viral infection affecting the liver), you are eligible if you have been taking antiviral medications for at least 4 weeks and the virus is not detectable in your blood
  • If you have had hepatitis C (another type of viral liver infection) in the past, the virus must not be detectable in your blood at the time of screening

Who cannot join the trial?

3 criteria

  • The source data does not provide specific exclusion criteria (reasons why a patient cannot participate) for this clinical trial.
  • If you are interested in this study, you will need to discuss with the research team to learn what conditions or situations would prevent participation.
  • Common reasons patients may not be able to join studies include having certain other diseases, taking specific medications, or having had particular treatments in the past, but these specific details are not available in the provided information.
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Investigated drugs

MK-3120 is an investigational medication being studied as a treatment for high-risk bladder cancer that has not spread into the muscle layer of the bladder wall. This medication is given directly into the bladder through a catheter, which is a thin tube inserted through the urethra. The purpose of using this medication in the trial is to see if it is safe and well-tolerated by patients, and to determine if it can help treat bladder cancer in people who have either never received BCG treatment before or who have been previously exposed to BCG treatment. BCG is a common bladder cancer treatment that uses a weakened form of bacteria to stimulate the immune system to fight cancer cells.

What is already known about the treatment

MK-3120 – MK-3120 is an investigational medication administered directly into the bladder (intravesical administration) for the treatment of high-risk non-muscle invasive bladder cancer, particularly in cases involving carcinoma in situ. This experimental drug is currently being studied in Phase 1/2 clinical trials to evaluate its safety and effectiveness in patients who have either never received BCG treatment or have been previously exposed to it. The exact mechanism of action at the molecular level has not been fully disclosed in the available trial information, but it is being developed as a potential alternative therapy for bladder cancer patients who need treatment options beyond standard BCG immunotherapy.

Investigated diseases

  • Non-muscle Invasive Bladder Cancer

    Non-muscle invasive bladder cancer is a type of cancer that develops in the inner lining of the bladder but has not grown into the deeper muscle layers of the bladder wall. This form of cancer typically begins in the cells that line the inside of the bladder and remains confined to the superficial layers. The disease can present as flat lesions or as papillary tumors that grow outward into the bladder cavity. Non-muscle invasive bladder cancer has a tendency to recur after treatment, requiring ongoing monitoring. The progression of this disease varies, with some cases remaining stable while others may advance to more invasive forms over time.

  • Carcinoma In Situ of the Bladder

    Carcinoma in situ of the bladder is a flat, high-grade cancerous growth that remains in the innermost layer of the bladder lining without invading deeper tissues. Unlike papillary tumors that grow outward, carcinoma in situ appears as a red, velvety patch on the bladder wall. This condition is considered a high-risk form of bladder cancer due to its aggressive nature and potential to progress. The abnormal cells in carcinoma in situ are severely damaged and have a higher likelihood of spreading into the muscle layer of the bladder if left unmanaged. Patients with this condition often experience symptoms such as frequent urination and blood in the urine. The disease can occur alone or alongside papillary tumors in the bladder.

Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase ITrial ID2025-520467-40-00Protocol codeMK-3120-003Estimated enrolment46 patientsSponsorMerck Sharp & Dohme LLC

sourced from the EU Clinical Trials Register and site verification

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