An Investigational Immuno-therapy Study of Nivolumab, or Nivolumab in Combination With Ipilimumab, or Placebo in Patients With Extensive-Stage Disease Small Cell Lung Cancer (ED-SCLC) After Completion of Platinum-based Chemotherapy

Overall Survival (OS) of Nivolumab Versus Placebo

Overall Survival (OS) comparing nivolumab monotherapy versus placebo. OS was defined as the time from randomization to the date of death. A participant who had not died was censored at last known alive date. OS was followed up during the blinded study drug treatment and every 3 months via in-person or phone contact after participant discontinued the blinded study drug.

Time frame: From randomization to the date of death or last known alive date (up to approximately 73 months)

Overall Survival (OS) of Nivolumab + Ipilimumab Versus Nivolumab

Overall Survival (OS) comparing Nivolumab + Ipilimumab Versus Nivolumab. OS was defined as the time from randomization to the date of death. A participant who had not died was censored at last known alive date. OS was followed up during the blinded study drug treatment and every 3 months via in-person or phone contact after participant discontinued the blinded study drug.

Time frame: From randomization to the date of death or last known alive date (up to approximately 73 months)

Progression Free Survival (PFS) Per BICR

PFS was defined as the time between the date of randomization and the first date of documented progression as determined by Blind Independent Central Review (BICR) or death due to any cause, whichever occurred first. Participants who died with no reported progression were considered to have progressed on the date of death. Participants who did not progress or die were censored on the date of their last evaluable tumor assessment on or prior to initiation of the subsequent anti-cancer therapy. Participants who did not have any on study tumor assessments and did not die (or died after initiation of the subsequent anti- cancer therapy) were censored on their date of randomization. Participants who started any subsequent anti- cancer therapy without a prior reported Progressive Disease (PD) per BICR were censored at the last evaluable tumor assessment on or prior to initiation of the subsequent anti-cancer therapy.

Time frame: From randomization to the date of the first documented tumor progression or death due to any cause (up to approximately 73 months)

Overall Survival (OS) in Tumor Mutational Burden (TMB) High and Low Subgroups by TMB Cutoff In The Global Population

Tumor mutational burden (TMB) is measured using FoundationOne CDxTM (F1CDx) assay, a comprehensive genomic profile (CGP) assay based on baseline tumor tissue. TMB is defined as the number of somatic, coding, base substitution, and indel mutations per megabase of genome examined. OS in TMB by the following cutoff points: ≥10 mutations/mb, \< 10 mutations/mb, ≥13 mutations/mb, \<13 mutations/mb

Time frame: From randomization to the date of death or last known alive date (up to approximately 73 months)

Progression Free Survival (PFS) Per BICR in Tumor Mutational Burden (TMB) High and Low Subgroups by TMB Cutoff In The Global Population

Tumor mutational burden (TMB) is measured using FoundationOne CDxTM (F1CDx) assay, a comprehensive genomic profile (CGP) assay based on baseline tumor tissue. TMB is defined as the number of somatic, coding, base substitution, and indel mutations per megabase of genome examined. PFS in TMB by the following cutoff points: ≥10 mutations/mb, \< 10 mutations/mb, ≥13 mutations/mb, \<13 mutations/mb.

Time frame: From randomization to the date of the first documented tumor progression or death due to any cause (up to approximately 73 months)