Skip to content
Clinical Trials – home

Rare diseases

Investigational molecules

Locations

Our offerNewsroom

Not recruiting

Study of MK-4280A (Favezelimab and Pembrolizumab) for Patients with Metastatic Colorectal Cancer After Previous Treatment

Verified siteRegistered drugNo placebo
Clinical Trials Concierge

Prefer not to search? Our Concierge searches the trials for you.

What is this trial about?

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

The study focuses on people with advanced Colorectal Cancer that has spread to other parts of the body and shows a protein called PD‑L1. The investigational treatment, identified by the code name MK‑4280A, combines two medicines: an intravenous infusion of pembrolizumab and favezelimab. This new combination is being compared with the usual care options, which include an oral pill called regorafenib and a tablet regimen known as TAS‑102 that contains the substances trifluridine and tipiracil.

The purpose of the trial is to determine whether the new combination can help patients live longer than the standard medicines. Participants are assigned to receive either the study infusion or one of the standard oral treatments, and they will receive the assigned medication in regular cycles while being monitored through clinic visits, blood tests, and imaging scans.

Throughout the study, researchers will track how long participants survive after starting treatment, note any side effects (called adverse events), and ask participants to complete questionnaires about their daily well‑being and overall quality of life. Simple explanations are provided for any medical terms used, ensuring that the information remains clear and understandable.

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

    Joining the study

    Upon joining the study, eligibility is confirmed based on specific criteria, including having a type of colorectal cancer that has spread and cannot be removed by surgery.

    A sample of the tumor is required, either from a previous biopsy or a new one, to ensure it meets the study's requirements.

  2. Step 2

    Initial assessment

    An initial assessment is conducted to evaluate the current state of the disease using specific criteria for measuring tumors.

    The patient's ability to perform daily activities is assessed, and a life expectancy of at least three months is required.

  3. Step 3

    Treatment phase

    The treatment involves receiving the study medication MK-4280A, which is a combination of two substances, favezelimab and pembrolizumab, administered through an intravenous infusion.

    Alternatively, standard treatments such as regorafenib or a combination of trifluridine and tipiracil may be used, which are taken orally.

  4. Step 4

    Monitoring and follow-up

    Regular monitoring is conducted to assess the response to the treatment, including measuring the size of the tumors and checking for any side effects.

    Quality of life is evaluated using specific questionnaires to understand the impact of the treatment on daily living.

  5. Step 5

    Completion of the study

    The study is expected to continue until November 2025, with regular assessments to determine the overall survival and progression-free survival.

    Upon completion, the results will be analyzed to compare the effectiveness of the study medication against standard treatments.

Who can join the trial?

8 criteria

  • The patient must have a confirmed diagnosis of colorectal adenocarcinoma, which means a type of cancer that starts in the colon or rectum, and it must be metastatic (spread to other parts of the body) and unresectable (cannot be removed by surgery).
  • The patient must have measurable disease according to specific criteria used by doctors to assess tumors.
  • The patient must have been previously treated for colorectal cancer and the disease must have progressed (gotten worse) after treatment, or the patient could not tolerate the standard treatment.
  • The patient must provide a tumor tissue sample that is either from the past 5 years or newly obtained, and it must not have been treated with radiation before.
  • The patient must have an ECOG Performance Score of 0 to 1, which is a scale used to assess how well a patient can perform daily activities. A score of 0 means fully active, and 1 means some symptoms but nearly fully active.
  • The patient must have a life expectancy of at least 3 months, as judged by the doctor.
  • The patient must be able to swallow and retain oral medication and should not have any significant stomach or intestinal issues that could affect how the medicine is absorbed.
  • The patient must have adequate organ function, meaning the organs are working well enough to handle the treatment.

Who cannot join the trial?

4 criteria

  • Patients who have a different type of cancer other than Colorectal Cancer cannot participate.
  • Patients who are not within the specified age range for the study cannot participate.
  • Patients who are part of a vulnerable population, which means they might need special protection or care, cannot participate.
  • Patients who are not eligible for the standard treatments being compared in the study, such as regorafenib or TAS-102, cannot participate.
Clinical Trials Concierge

Prefer not to search? Our Concierge searches the trials for you.

Tell us about your condition – we search every trial in Europe and connect you with the right site.

We usually reply within a few days

Verified sites

All sites with verified contact details – recruitment status may not be available; ask directly

Trial locations

Where you can join this trial

Countries are shaded by recruitment status. Click a recruiting country to ask about joining there.

Not recruiting
Not finding your country?

Not sure what to do next?

Joining a clinical trial can seem overwhelming. We guide you step by step, so you know exactly what to expect and how we support you through the process.

See the full process and FAQ

Investigated drugs

  • MK-4280A

    is a combination of two medications, favezelimab and pembrolizumab. This combination is being studied to see if it can help people with a type of colorectal cancer that has already been treated and is positive for PD-L1. The goal is to see if this combination can help patients live longer compared to other treatments.

  • Regorafenib

    is a medication used in this study as a standard treatment option. It works by blocking certain proteins that help cancer cells grow, which may help slow down or stop the growth of cancer.

  • TAS-102

    is another standard treatment option in this study. It is a combination of two drugs that work together to interfere with the growth of cancer cells, potentially helping to control the cancer.

What is already known about the treatment

MK-4280A – This medication is administered intravenously and is currently being studied in clinical trials for its effectiveness in treating metastatic colorectal cancer that is PD-L1 positive. It is a combination of two drugs, favezelimab and pembrolizumab, and is being compared to standard treatments like regorafenib or TAS-102. The main therapeutic indication is for patients who have previously been treated for this type of cancer. At the molecular level, MK-4280A works by targeting and inhibiting specific proteins that help cancer cells evade the immune system, thereby enhancing the body's ability to fight the cancer. It falls under the pharmacological classification of immune checkpoint inhibitors.

Investigated diseases

Colorectal Cancer – Colorectal cancer is a type of cancer that begins in the colon or rectum, parts of the large intestine. It often starts as small, noncancerous clumps of cells called polyps that form on the inside of the colon or rectum. Over time, some of these polyps can become cancerous. The disease may cause changes in bowel habits, such as diarrhea or constipation, and may also lead to blood in the stool. As it progresses, it can spread to other parts of the body, affecting organs and tissues beyond the colon and rectum. Early stages may not present noticeable symptoms, making regular screenings important for detection.
Trial detailsLast updated 14 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2024-511043-25-00Protocol codeMK-4280A-007Estimated enrolment689 patientsSponsorMerck Sharp & Dohme LLC

sourced from the EU Clinical Trials Register and site verification

Want to learn more about this trial or check if you can participate?

Clinical Trials Concierge

Prefer not to search? Our Concierge searches the trials for you.

Tell us about your condition – we search every trial in Europe and connect you with the right site.