Skip to content
Clinical Trials – home

Rare diseases

Investigational molecules

Locations

Our offerNewsroom

Recruiting

Study of mRNA-4157 and Pembrolizumab for Patients with Metastatic Melanoma

Fast replyRegistered drug
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

This clinical trial is investigating melanoma, a type of skin cancer that has spread and cannot be surgically removed (unresectable). The study focuses on Stage III or IV cutaneous melanoma that has metastasized (spread to other parts of the body). The treatment being studied combines an investigational medication called V940 (also known as mRNA-4157) with an immunotherapy drug called pembrolizumab. The purpose of this research is to determine if adding V940 to pembrolizumab treatment provides better results than pembrolizumab with placebo in people with melanoma who haven't yet received treatment for their metastatic disease.

The study is designed as a Phase 2 clinical trial that will randomly assign participants to receive either V940 plus pembrolizumab or placebo plus pembrolizumab. Participants will need to have at least one measurable tumor that can be detected by computed tomography (CT scan) or magnetic resonance imaging (MRI). They will also need to provide tumor tissue samples for genetic analysis and biomarker testing. The trial will measure how long participants live without their cancer getting worse, as well as other factors like tumor response rates and overall survival.

The research process

The trial runs in 6 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Joining the trial and randomization

    After joining the clinical trial for metastatic melanoma (advanced skin cancer that has spread), you will be randomly assigned to one of two treatment groups. One group will receive V940 (mRNA-4157) plus pembrolizumab, and the other group will receive a placebo plus pembrolizumab.

    This is a double-blind study, which means neither you nor your doctor will know which treatment group you are in until after the study is completed.

  2. Step 2

    Initial tumor tissue collection

    You will need to provide a tumor tissue sample, preferably from a metastatic site (where the cancer has spread) or from the primary tumor if a metastatic sample is not available.

    This tissue will be used for next generation sequencing and biomarker analysis, which helps researchers understand your specific type of cancer and how it might respond to treatment.

  3. Step 3

    Treatment administration

    You will receive regular treatments with pembrolizumab (also known as KEYTRUDA), which is given as an intravenous infusion (through a vein). The concentration of pembrolizumab is 25 mg/mL.

    Depending on your assigned group, you will also receive either V940 (mRNA-4157) as an injection or a placebo injection that contains no active medication.

    These treatments will continue according to the study schedule until your disease progresses, you experience unacceptable side effects, or the study ends.

  4. Step 4

    Regular monitoring and assessments

    Throughout the trial, you will undergo regular imaging scans (CT or MRI) to measure your tumors and assess how they're responding to treatment.

    Your doctor will evaluate your response using criteria called RECIST 1.1 (Response Evaluation Criteria in Solid Tumors), which is a standardized way to measure changes in tumor size.

    Blood tests and other medical examinations will be performed regularly to monitor your overall health and any potential side effects from the treatments.

  5. Step 5

    Side effect monitoring

    Throughout the study, you will be monitored for any adverse events (side effects or negative reactions) that might occur during treatment.

    If you experience severe side effects, your doctor might adjust your treatment or, if necessary, discontinue your participation in the study.

  6. Step 6

    Follow-up period

    After completing the treatment period, you will enter a follow-up phase where your health will continue to be monitored.

    The study is expected to run until June 2028, with the primary completion date in June 2025.

    During follow-up, researchers will track your overall survival and whether your cancer has progressed.

Who can join the trial?

8 criteria

  • Have unresectable Stage III or IV cutaneous melanoma (skin cancer that cannot be completely removed by surgery) confirmed by tissue examination
  • Have not received any previous treatment for melanoma except if you had prior therapy for early-stage disease, and your cancer did not return within 12 months after stopping treatment
  • Have documentation of your BRAF mutation status (a specific genetic change that can occur in melanoma)
  • Have at least one measurable tumor that can be seen on CT scan or MRI
  • Be able to provide a tumor tissue sample for testing
  • If you have HIV, it must be well controlled with medication
  • If you have hepatitis B, you must have been on antiviral therapy for at least 4 weeks with undetectable viral levels
  • If you have a history of hepatitis C, the virus must be undetectable at screening

Who cannot join the trial?

10 criteria

  • Has received previous treatment with any form of immunotherapy for melanoma, including pembrolizumab or similar drugs.
  • Has a medical condition that requires long-term treatment with steroids or other medications that suppress the immune system.
  • Has an active autoimmune disease (a condition where the immune system attacks the body's own tissues) that has required treatment in the past 2 years.
  • Has had another cancer that has not been successfully treated or has been treated within the last 3 years.
  • Has active brain metastases (cancer that has spread to the brain) or carcinomatous meningitis (cancer in the fluid around the brain and spinal cord).
  • Has received a live vaccine within 30 days before starting the study treatment.
  • Is pregnant or breastfeeding, or planning to become pregnant during the study period.
  • Has a serious infection requiring treatment, including HIV, hepatitis B, or hepatitis C.
  • Has a history of pneumonitis (lung inflammation) requiring steroids.
  • Has severe heart disease or other serious medical conditions that might make participation unsafe.
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.

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

  • V940 (mRNA-4157)

    is an experimental mRNA-based therapy designed to help the immune system recognize and attack cancer cells. It is being tested in combination with pembrolizumab for treating melanoma, a type of skin cancer that has spread to other parts of the body.

  • Pembrolizumab

    is an immunotherapy medication that helps the body's immune system detect and fight cancer cells. It works by blocking a protein called PD-1, which normally prevents the immune system from attacking cancer cells. By blocking this protein, pembrolizumab allows the immune system to recognize and destroy cancer cells more effectively.

What is already known about the treatment

  • V940 (mRNA-4157)

    This is an investigational mRNA cancer vaccine administered by injection that is being studied in clinical trials for melanoma treatment. Currently in Phase 2 clinical trials, V940 is designed to stimulate the immune system to recognize and attack specific cancer cells by encoding for neoantigens (unique proteins found on tumor cells). The mechanism involves delivering messenger RNA that instructs the body's cells to produce proteins resembling those on the patient's specific tumor, triggering an immune response against the cancer. It is being studied in combination with pembrolizumab as a potential first-line treatment for metastatic melanoma.

  • Pembrolizumab

    This is an FDA-approved immunotherapy medication administered as an intravenous infusion for treating various cancers, including melanoma. Pembrolizumab works by binding to the PD-1 receptor on T cells, blocking its interaction with PD-L1 and PD-L2, which helps restore the body's immune response against cancer cells. It belongs to a class of drugs called immune checkpoint inhibitors and is indicated for the treatment of advanced melanoma, as well as several other cancer types. Pembrolizumab is well-established in medical literature as an effective treatment that helps the immune system recognize and attack cancer cells.

Investigated diseases

Melanoma - A type of skin cancer that develops in the melanocytes, which are cells that produce melanin, the pigment responsible for skin color. Melanoma often starts as a new or changing mole on the skin's surface. It can occur anywhere on the body, but commonly appears on the chest, back, legs, and face. Melanoma has the ability to spread (metastasize) to other parts of the body if not detected early. The disease typically progresses through stages from localized disease to regional spread and potentially distant metastasis. Risk factors include excessive ultraviolet radiation exposure, fair skin, multiple or atypical moles, and family history of melanoma.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IITrial ID2024-519605-36-00Protocol codeV940-012Estimated enrolment176 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.