The trial focuses on people who have had surgery to remove a small, early form of non-small cell lung cancer that was classified as Stage I. Participants are randomly assigned to receive either a new combination that includes an injectable medicine called pembrolizumab together with a gene‑based product named mRNA-4157 (intismeran autogene) and an enzyme, or a simple injection that contains no active drug, referred to as V940placebo. The purpose is to find out whether the new combination can keep the cancer from returning.
After the surgery, each person receives the assigned injection—either under the skin (subcutaneous) or into a muscle (intramuscular)—on a schedule set by the study team. Follow‑up visits are planned regularly to check health, monitor any side effects, and assess overall well‑being.
During the study, doctors will watch for any adverse events (unwanted health problems) and ask participants to complete questionnaires about their quality of life and daily functioning. This information helps determine if the treatment is safe and if it improves outcomes compared with the control injection.
1enrollment and randomization
after signing the consent form, you are assigned to one of the study groups by a computer system.
the groups may include pembrolizumab plus mrna-4157, pembrolizumab alone, or placebo.
2baseline assessments
a series of tests are performed to record your health status before treatment begins.
these tests may include blood work, imaging scans, and questionnaires about quality of life.
3first injection
if you are assigned to the pembrolizumab group, a single injection of 790 mg of pembrolizumab is given under the skin (subcutaneous use).
if you are also assigned to receive mrna-4157, a single injection of 1 mg is given into the muscle (intramuscular).
if you are assigned to the placebo group, a matching injection that does not contain active drug is given.
4subsequent injections
additional injections of the same type and dose are given at intervals defined by the study protocol.
each injection follows the same route: subcutaneous for pembrolizumab and intramuscular for mrna-4157.
5regular clinic visits
you attend scheduled visits to the clinic where health professionals check for side effects and overall well‑being.
blood samples and imaging scans may be performed to monitor disease status.
6disease monitoring
periodic scans are done to assess disease‑free survival, which means checking whether the cancer has returned.
the assessments are reviewed by an independent central review team.
7reporting side effects
any new symptoms or changes in health are recorded and reported to the study team during visits or by phone.
the study records the number of participants who experience adverse events and those who stop treatment because of them.
8possible treatment discontinuation
if severe side effects occur, the study protocol may require stopping the injections.
the decision is made according to predefined safety criteria.
9final assessment
at the end of the study period, a comprehensive evaluation is performed, including final imaging, blood tests, and quality‑of‑life questionnaires.
the results contribute to the overall analysis of the trial.
Who Can Join the Study?
You must have a diagnosis from tissue testing that shows Stage I non‑small cell lung cancer (NSCLC), which means a tumor 4 cm or smaller in the lung, according to the American Joint Committee on Cancer (AJCC) 9th Edition staging system, and you must have at least one of these high‑risk features: a tumor larger than 2 cm, cancer that has reached the lining of the lung (visceral pleural invasion), cancer cells found in blood or lymph vessels (lymphovascular invasion), or a tumor that looks aggressive under the microscope (high‑grade histology).
You must have had the entire tumor removed by surgery (complete surgical resection).
You must not have received any other cancer treatment such as chemotherapy, immunotherapy, targeted therapy, or radiation after the surgery.
You must give a small piece of tissue from the recent surgery and a blood sample for the study.
If you have human immunodeficiency virus (HIV), your infection must be well‑controlled with medicines called antiretroviral therapy (ART).
If you test positive for hepatitis B surface antigen (HBsAg), you can join only if you have been on hepatitis B antiviral medicine for at least four weeks and your hepatitis B virus (HBV) level in the blood is undetectable before randomization.
If you have a history of hepatitis C virus (HCV) infection, you can join only if the HCV level in your blood is undetectable at the screening visit.
Who Cannot Join the Study?
Diagnosis of small cell lung cancer (a fast‑growing type of lung cancer) or tumors that contain small‑cell parts, large‑cell neuroendocrine cancer, sarcomatoid carcinoma, or two separate non‑small cell lung cancers at the same time.
Any serious cardiovascular disease (heart or blood‑vessel problems) within the past year, such as heart bypass surgery, stent placement, severe valve disease needing surgery, advanced heart failure (class III‑IV), unstable chest pain, heart attack, high blood pressure in the lungs, stroke, or dangerous heart rhythm problems.
Being infected with HIV and having a history of Kaposi’s sarcoma (a skin/organ cancer) or Multicentric Castleman’s disease (a rare lymph‑node disorder).
Having another cancer that is getting worse or that needed active treatment within the last three years.
Having an active autoimmune disease (where the immune system attacks the body) that required strong medicines in the past two years. Regular hormone medicines like thyroid hormone, insulin, or normal‑dose steroids are allowed.
Having past or current non‑infectious lung inflammation (called pneumonitis or interstitial lung disease) that required steroids.
Having an ongoing infection that needs treatment with medicines, except the specific infections allowed in the study.
Having a history of a stem‑cell transplant or a solid‑organ transplant.
Not fully recovered from major surgery or still having problems from surgery.
Pembrolizumab is an immunotherapy drug that helps the body’s immune system recognize and attack cancer cells. In this trial it is given as a subcutaneous injection, meaning it is administered just under the skin. The medication works by blocking a protein called PD‑1 on immune cells, which can release the “brakes” on the immune response and allow the cells to target the lung cancer more effectively.
mRNA-4157 is a personalized cancer vaccine that uses a small piece of messenger RNA to teach the immune system to recognize proteins that are unique to a patient’s tumor. It is injected into a muscle (intramuscular injection). By presenting these tumor‑specific signals, the vaccine aims to stimulate the body’s own defenses to seek out and destroy any remaining cancer cells after surgery.
Non‑small cell lung cancer – It is a type of lung cancer that begins in the cells lining the airways. The disease often starts as a small tumor that may stay localized to the lung for a time. Over months or years it can enlarge and spread to nearby lymph nodes. If it continues to grow, cancer cells may travel through the bloodstream to distant organs.
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