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Study Comparing MK-1308A and Pembrolizumab for Patients with Advanced Colorectal Cancer with High Microsatellite Instability or Mismatch Repair Deficiency

Verified siteRegistered drugNo placebo
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What is this trial about?

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

This clinical trial is focused on studying treatments for Stage IV Colorectal Cancer, specifically in patients with a condition known as Microsatellite Instability-High (MSI-H) or Mismatch Repair Deficient (dMMR). These are specific types of genetic changes in cancer cells that can affect how the cancer grows and responds to treatment. The study will explore the effectiveness of several treatments, including a combination of drugs called MK-1308A (which includes quavonlimab and pembrolizumab), as well as other treatments like MK-4280A, MK-7684A, and MK-4830 combined with pembrolizumab. Pembrolizumab is also being tested on its own.

The purpose of the study is to compare how well these treatments work in shrinking tumors and improving patient outcomes. Participants will receive these treatments through an intravenous infusion, which means the medication is given directly into a vein. The study will be conducted over a period of time, and participants will be monitored to see how their cancer responds to the treatment. The study will also look at how long the response lasts, how long patients live without the cancer getting worse, and overall survival rates.

Throughout the study, the safety of the treatments will be closely monitored, and any side effects will be recorded. The study aims to provide valuable information on the effectiveness of these treatments for patients with this specific type of colorectal cancer, potentially leading to better treatment options in the future.

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 assessment

    Upon joining the study, you will undergo an initial assessment to confirm your eligibility. This includes verifying your diagnosis of Stage IV colorectal cancer with specific characteristics known as microsatellite instability-high (MSI-H) or mismatch repair deficient (dMMR).

    You will need to provide a sample of your tumor tissue, which can be either an archival sample or a newly obtained one. This sample should not have been previously treated with radiation.

  2. Step 2

    Treatment assignment

    You will be assigned to a treatment group. The study involves different treatment options, including MK-1308A (a combination of quavonlimab and pembrolizumab), pembrolizumab alone, or other combinations such as MK-4280A, MK-7684A, and MK-4830 with pembrolizumab.

    The treatment you receive will be administered through an intravenous infusion, which means the medication will be given directly into your vein.

  3. Step 3

    Treatment administration

    You will receive your assigned treatment at regular intervals. The specific dosage and frequency will depend on the treatment group you are in.

    The duration of the treatment will be determined by the study protocol and your response to the treatment.

  4. Step 4

    Regular monitoring

    Throughout the study, you will have regular check-ups to monitor your health and the effectiveness of the treatment. This includes physical exams, blood tests, and imaging studies.

    Your response to the treatment will be evaluated using criteria known as RECIST 1.1, which helps in assessing changes in tumor size.

  5. Step 5

    End of treatment

    At the end of the treatment period, you will have a final assessment to evaluate the overall impact of the treatment on your condition.

    You may be asked to continue follow-up visits to monitor your health and any long-term effects of the treatment.

Who can join the trial?

9 criteria

  • Must have a confirmed diagnosis of Stage IV Colorectal Cancer (a type of cancer that starts in the colon or rectum).
  • Must have a specific type of cancer called Mismatch Repair Deficient (dMMR) or Microsatellite Instability-High (MSI-H).
  • Must have a life expectancy of at least 3 months.
  • Female participants must not be pregnant or breastfeeding. If they can have children, they must use a highly effective birth control method or be consistently abstinent during the study and for at least 120 days after the last dose.
  • Must have cancer that can be measured by medical imaging techniques.
  • Must provide a sample of the tumor tissue, either from a previous biopsy within the last 5 years or a new one, that has not been treated with radiation.
  • Must have organs that are functioning well enough to participate in the study.
  • For Cohort A: Must have been previously treated for Stage IV dMMR/MSI-H colorectal cancer and the cancer must have progressed after or could not tolerate standard treatments, which include specific chemotherapy drugs and possibly certain targeted therapies.
  • For Cohort B: Must have untreated Stage IV dMMR/MSI-H colorectal cancer with no prior chemotherapy or immunotherapy for this disease.

Who cannot join the trial?

1 criterion

  • Participants with **Microsatellite Instability-High (MSI-H)** or **Mismatch Repair Deficient (dMMR)** Stage IV Colorectal Cancer cannot join. These are specific types of genetic changes in cancer cells.
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Investigated drugs

  • MK-1308A

    is a combination of two medications, quavonlimab and pembrolizumab, that are used together to help the body's immune system fight cancer. This combination is being tested to see if it can help people with a specific type of colorectal cancer that has certain genetic features, known as microsatellite instability-high (MSI-H) or mismatch repair deficient (dMMR). The goal is to see if this combination can shrink the cancer or stop it from growing.

  • Pembrolizumab

    is a medication that helps the immune system recognize and attack cancer cells. It is used on its own in this study to see how well it works in treating colorectal cancer with the same genetic features mentioned above. Researchers want to find out if pembrolizumab alone can effectively reduce the size of the cancer or halt its progression.

  • MK-4280A

    is another experimental treatment being tested in this study. It is designed to work with the immune system to target and destroy cancer cells. The study aims to determine if MK-4280A can be an effective treatment option for patients with the specific type of colorectal cancer being studied.

  • MK-7684A

    is a therapy that is also being evaluated in this clinical trial. Like the other treatments, it is intended to help the immune system fight cancer. The researchers are investigating whether MK-7684A can help control or reduce the cancer in patients with the genetic features of MSI-H or dMMR colorectal cancer.

  • MK-4830

    combined with pembrolizumab is another treatment option being tested. MK-4830 is designed to enhance the immune system's ability to attack cancer cells, and when used with pembrolizumab, it may offer a stronger response against the cancer. The study is looking to see if this combination can be more effective than other treatments in managing the cancer.

What is already known about the treatment

MK-1308A – This medication is administered as an injection and is currently being studied in clinical trials for its effectiveness in treating a specific type of advanced colorectal cancer known as Microsatellite Instability-High (MSI-H) or Mismatch Repair Deficient (dMMR) Stage IV. It is a combination of two drugs, quavonlimab and pembrolizumab, which work by helping the immune system recognize and attack cancer cells more effectively. MK-1308A is classified as an immunotherapy, a type of treatment that uses the body's own immune system to fight cancer.

Investigated diseases

Microsatellite Instability-High (MSI-H) or Mismatch Repair Deficient (dMMR) Stage IV Colorectal Cancer – This is a type of colorectal cancer characterized by genetic mutations that affect the DNA repair process, leading to high levels of microsatellite instability. In stage IV, the cancer has spread beyond the colon to other parts of the body, such as the liver or lungs. The disease progresses as cancer cells continue to grow and spread, forming new tumors in other organs. This type of cancer can cause symptoms like changes in bowel habits, blood in the stool, and abdominal pain. As the disease advances, it may lead to more severe symptoms due to the involvement of other organs. The progression of the disease is influenced by the genetic instability that allows cancer cells to multiply rapidly.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IVTrial ID2022-502100-70-00Protocol codeMK-1308A-008Estimated enrolment402 patientsSponsorMerck Sharp & Dohme LLC

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