after you have signed the consent form, the study staff records your participation and assigns you to one of the study groups using a random process. the assignment determines which medication you will receive.

before the first dose, you undergo imaging scans, blood tests, and questionnaires that evaluate your current health and quality of life.

if you are assigned to the combination group, you receive a subcutaneous injection of pembrolizumab 790 mg and an intramuscular injection of mrna-4157 1 mg.

if you are assigned to the monotherapy group, you receive only the intramuscular injection of mrna-4157 1 mg.

if you are assigned to the placebo group, you receive a placebo injection that does not contain active medication.

at each scheduled visit, you receive the same injection(s) as in the first dose according to the study schedule.

the route of administration remains subcutaneous for pembrolizumab and intramuscular for mrna-4157.

during each visit, blood samples and health questionnaires are collected to check for any adverse events, which are side effects that may be related to the study medication.

periodic imaging scans are performed to assess disease‑free survival, which measures the time you remain free of cancer recurrence.

treatment continues until the study protocol defines an end point, until disease recurrence is detected, or until a serious adverse event requires stopping the medication.

at the conclusion of the study, final imaging, laboratory tests, and quality‑of‑life questionnaires are completed to evaluate the overall outcomes of the trial.