A Trial to See if the Combination of Fianlimab With Cemiplimab Works Better Than Pembrolizumab for Preventing or Delaying Melanoma From Coming Back After it Has Been Removed With Surgery

Time from randomization to the first documented recurrence of disease at any site (excluding new primary melanomas) or death from any cause, whichever occurs first.

Time between the date of randomization and the date of the first distant metastasis.

Time from randomization to the date of death.

A TEAE is any untoward medical occurrence in a patient or clinical investigation subject administered a pharmaceutical product, which does not necessarily have a causal relationship with this treatment.

imAEs are a unique set of toxicities thought to be caused by unrestrained cellular immune responses.

An SAE is any untoward medical occurrence that at any dose:

• Results in death - includes all deaths, even those that appear to be completely unrelated to study drug (eg, a car accident in which a patient is a passenger).
• Is life-threatening
• Requires in-patient hospitalization or prolongation of existing hospitalization.
• Results in persistent or significant disability/incapacity
• Is a congenital anomaly/birth defect.
• Is an important medical event

An AESI (serious or non-serious) is one of scientific and medical concern specific to the sponsor's product or program, for which ongoing monitoring and rapid communication by the Investigator to the sponsor can be appropriate. Such an event might warrant further investigation in order to characterize and understand it

A TEAE resulting in death is any untoward medical occurrence in a patient or clinical investigation subject administered a pharmaceutical product, which does not necessarily have a causal relationship with this treatment.

A DLT is defined as a study-drug related TEAE, including imAEs, that could preclude enrolling additional adolescent patients at the selected dose. Dose-limiting toxicity will be evaluated in adolescents only.

A TEAE is any untoward medical occurrence in a patient or clinical investigation subject administered a pharmaceutical product, which does not necessarily have a causal relationship with this treatment.

As assessed by the NCI-CTCAE grading system (≥ Grade 3 or higher)

The concentrations of fianlimab over time will be summarized by descriptive statistics by study arm for the overall population and for adolescent patients.

The concentrations of cemiplimab over time will be summarized by descriptive statistics by study arm for the overall population and for adolescent patients.

Immunogenicity will be characterized per drug molecule by ADA and NAb status.

Immunogenicity will be characterized per drug molecule by ADA and NAb status.

The EORTC QLQ-C30 (Version 3) uses for the questions 1 to 28 a 4-point scale. The scale scores from 1 to 4: 1 ("Not at all"), 2 ("A little"), 3 ("Quite a bit") and 4 ("Very much"). Half points are not allowed. The range is 3. For the raw score, less points are considered to have a better outcome.

The EORTC QLQ-C30 (Version 3) uses for the questions 29 and 30 a 7-points scale. The scale scores from 1 to 7: 1 ("very poor") to 7 ("excellent"). Half points are not allowed. The range is 6. More points are considered to have a better outcome.

The EQ-5D-5L a descriptive system that comprises five dimensions: mobility, self-care, usual activities, pain/discomfort and anxiety/depression. Each dimension has 5 levels: no problems, slight problems, moderate problems, severe problems and extreme problems. The patient is asked to indicate his/her health state by ticking the box next to the most appropriate statement in each of the five dimensions. This decision results in a 1-digit number that expresses the level selected for that dimension. The digits for the five dimensions can be combined into a 5-digit number that describes the patient's health state.

The FACT-M is a melanoma-specific quality of life questionnaire that is composed of items from the Functional Assessment of Cancer Therapy-General (FACT-G). The FACT-M is scored on a 5 point Likert-scale: "Not at all", "A little bit", "Somewhat", "Quite a bit", and "Very much.". A Higher score represents higher Health Related Quality of Life (HRQoL).

The PGIS is a single 1-item questionnaire designed to assess participant's overall impression of disease severity at a given point in time by using a 4-point Likert scale that ranges from (1) = "none (no symptoms)" to (4) = "severe".

The PGIC is a single-item questionnaire designed to assess the participant's overall sense of whether there has been a change since starting treatment as rated on a 5-point Likert scale anchored by (1) "much better" to (5) "much worse", with (4) = "no change".