OS is defined as the time between the date of randomization and the date of death due to any cause. A participant who has not died will be censored at the last known alive date.

All Randomized Participants: All enrolled Participants who were randomized to any treatment arm.

PFS was defined as the time from randomization to the date of the first documented tumor progression or death due to any cause. Participants who did not have disease progression or who did not die were censored at the date of last tumor assessment. Participants who did not have any on study tumor assessment and did not have tumor progression or die were censored at the randomization date. Participants who started any subsequent anti-cancer therapy without a prior reported progression were censored at the last tumor assessment prior to initiation of the subsequent anti-cancer therapy. Participants who had surgical resection post start of study treatment were censored at the last tumor assessment date prior to initiation of surgical resection. PFS was determined by investigator reported response based on the Radiologic Assessment in Neuro-Oncology criteria.

All Randomized Participants

The overall survival (OS) rate of (nivolumab + radiation therapy) and (temozolomide + radiation therapy) estimated as Kaplan-Meier probability of survival at 24 months. OS was defined as the time between the date of randomization and the date of death due to any cause. A participant who has not died was censored at the last known alive date.

All Randomized Participants

OS in all randomized participants that are tumor mutational burden high. OS was defined as the time between the date of randomization and the date of death due to any cause. A participant who has not died was censored at the last known alive date.

Data was not and will never be collected

PFS in all randomized participants that are tumor mutational burden high. PFS was defined as the time from randomization to the date of the first documented tumor progression or death due to any cause. Participants who did not have disease progression or who did not die were censored at the date of last tumor assessment. Participants who did not have any on study tumor assessment and did not have tumor progression or die were censored at the randomization date. Participants who started any subsequent anti-cancer therapy without a prior reported progression were censored at the last tumor assessment prior to initiation of the subsequent anti-cancer therapy. Participants who had surgical resection post start of study treatment were censored at the last tumor assessment date prior to initiation of surgical resection. PFS was determined by investigator reported response based on the Radiologic Assessment in Neuro-Oncology criteria.

Data was not and will never be collected

OS was defined as the time between the date of randomization and the date of death due to any cause. A participant who has not died was censored at the last known alive date. Note: This outcome measure represents an updated version of the primary endpoint to include additional data collection that has occurred after the primary completion date (assessments were made until March 4, 2022).

All Randomized Participants