Study of Pembrolizumab (MK-3475) Versus Placebo After Complete Resection of High-Risk Stage III Melanoma (MK-3475-054/1325-MG/KEYNOTE-054)

RFS was defined as the time between the date of randomization and the date of first melanoma recurrence (local, regional, distant metastasis) or death (whatever the cause), whichever occurred first. For participants who remained alive and whose disease had not recurred, RFS was censored on the date of last visit/contact with disease assessments. The percentage of participants with RFS at Month 6 was reported for all participants in both treatment arms of Part 1.

RFS was defined as the time between the date of randomization and the date of first melanoma recurrence (local, regional, distant metastasis) or death (whatever the cause), whichever occurred first. For participants who remained alive and whose disease had not recurred, RFS was censored on the date of last visit/contact with disease assessments. The percentage of participants with RFS at Month 6 was reported for all participants with PD-L1-positive tumors in both treatment arms of Part 1.

DMFS will be defined as the time between the date of randomization and the date of first distant metastasis or date of death (whatever the cause), whichever occurs first. For participants who remain alive and distant metastasis-free, DMFS will be censored on the date of last visit/contact with disease assessments. The percentage of participants with DMFS will be reported for all participants in both treatment arms.

Description:

DMFS will be defined as the time between the date of randomization and the date of first distant metastasis or date of death (whatever the cause), whichever occurs first. For participants who remain alive and distant metastasis-free, DMFS will be censored on the date of last visit/contact with disease assessments. The percentage of participants with DMFS will be reported for all participants with PD-L1-positive tumors in both treatment arms.

OS will be defined as the time from the date of randomization to the date of death, whatever the cause. The follow-up of participants still alive will be censored at the moment of last visit/contact. OS will be reported for all participants in both treatment arms.

OS will be defined as the time from the date of randomization to the date of death, whatever the cause. The follow-up of participants still alive will be censored at the moment of last visit/contact. OS will be reported for all participants with PD-L1-positive tumors in both treatment arms.

An AE is defined as "any untoward medical occurrence in a participant which does not necessarily have to have a causal relationship with this treatment". An AE can therefore be any unfavorable and unintended signs (such as rash or enlarged liver), symptoms (such as nausea or chest pain), an abnormal laboratory finding (including results of blood tests, x-rays or scans) or a disease temporarily associated with the use of the protocol treatment, whether or not considered related to the investigational medicinal product. The number of participants who experienced at least 1 AE was reported for all participants in each treatment arm.

An AE is defined as "any untoward medical occurrence in a participant which does not necessarily have to have a causal relationship with this treatment". An AE can therefore be any unfavorable and unintended signs (such as rash or enlarged liver), symptoms (such as nausea or chest pain), an abnormal laboratory finding (including results of blood tests, x-rays or scans) or a disease temporarily associated with the use of the protocol treatment, whether or not considered related to the investigational medicinal product. The number of participants who discontinued study treatment due to an AE was reported for all participants in each treatment arm.

Blood samples were to be collected at pre-specified time points and plasma isolated for analysis of pembrolizumab CL, defined as the volume of plasma from which pembrolizumab is eliminated per unit time following IV pembrolizumab administration. Samples were not collected and this analysis was not performed.

Blood samples were to be collected at pre-specified time points and plasma isolated for analysis of pembrolizumab V, defined as the theoretical volume that would be necessary to contain the total amount of administered pembrolizumab at the same concentration that it is observed in the blood plasma. Samples were not collected and this analysis was not performed.

Pre- and post-baseline serum samples from participants treated with pembrolizumab were analyzed for ADA by means of a neutralizing antibody assay which assessed the ability of ADA to block (neutralize) binding of pembrolizumab to Programmed Cell Death-1 (PD-1) protein. Overall immunogenicity was defined as the number of treatment emergent positive participants based on the total number of evaluable participants (treatment emergent positive, non-treatment emergent positive and negative immunogenicity status).