PFS was defined as the time between the date of randomization and the first date of documented progression, as determined by the Investigator, or death due to any cause, whichever occurred first. Participants who died without a reported progression were considered to have progressed on the date of their death. Participants who did not progress or die were censored on the date of their last evaluable tumor assessment. Participants who did not have any on study tumor assessments and did not die were censored on their date of randomization. Participants treated beyond progression were considered to have progressive disease at the time of the initial progression event regardless of subsequent tumor response. Particpants who started anti-cancer therapy without a prior reported progression were censored on the date of their last evaluable tumor assessment prior to the initiation of subsequent anti-cancer therapy.

All randomized participants

OS was defined as the time between the date of randomization and the date of death. For participants without documentation of death, OS was censored on the last date the participant was known to be alive.

All randomized participants

OS was defined as the time between the date of randomization and the date of death. For participants without documentation of death, OS was censored on the last date the participant was known to be alive. The overall survival rate at time T (6, 12, or 24 months) was defined as the probability that a participant was alive at time T following randomization.

All randomized participants

PFS was defined as the time between the date of randomization and the first date of documented progression, as determined by the Investigator, or death due to any cause, whichever occurred first. Participants who died without a reported progression were considered to have progressed on the date of their death. Participants who did not progress or die were censored on the date of their last evaluable tumor assessment. Participants who did not have any on study tumor assessments and did not die were censored on their date of randomization. Participants treated beyond progression were considered to have progressive disease at the time of the initial progression event regardless of subsequent tumor response. Participants who started anti-cancer therapy without a prior reported progression were censored on the date of their last evaluable tumor assessment prior to the initiation of subsequent anti-cancer therapy.

All randomized participants

PFS was defined as the time between the date of randomization and the first date of documented progression, as determined by the Investigator, or death due to any cause, whichever occurred first. Participants who died without a reported progression were considered to have progressed on the date of their death. Participants who did not progress or die were censored on the date of their last evaluable tumor assessment. Participants who did not have any on study tumor assessments and did not die were censored on their date of randomization. Participants treated beyond progression were considered to have progressive disease at the time of the initial progression event regardless of subsequent tumor response. Participants who started anti-cancer therapy without a prior reported progression were censored on the date of their last evaluable tumor assessment prior to the initiation of subsequent anti-cancer therapy.

All randomized participants

OS was defined as the time between the date of randomization and the date of death. For participants without documentation of death, OS was censored on the last date the participant was known to be alive.

All randomized participants

The ORR was defined as the percentage of participants with a best overall response (BOR) of a complete response (CR) or partial response (PR) divided by the number of randomized participants for each arm. The BOR was defined as the best response designation, as determined by the Investigator, recorded between the date of randomization and the date of progression, as assessed by the Investigator per RECIST 1.1 or the date of subsequent anticancer therapy (including tumor-directed radiotherapy and tumor-directed surgery), whichever occurred first. For participants without evidence of RECIST 1.1 progression or subsequent anticancer therapy, all available response designations contributed to the BOR assessment. CR= Disappearance of all evidence of disease, confirmed by PET scan; PR= Regression of measureable disease and no new sites; Stable Disease (SD)= Failure to attain CR/PR or PD; Progressive Disease (PD)= Any new lesion or increase by >=50% of previously involved sites from nadir.

All randomized participants

PD-L1 expression was defined as the percent of tumor cells demonstrating plasma membrane PD-L1 staining of any intensity using an IHC assay. Tumor biopsy specimens without measurable PD-L1 expression were classified as indeterminate if the staining was hampered for reasons attributed to the biology of the specimen and not because of improper specimen preparation or handling. Missing specimens, specimens that were not optimally collected (ie not evaluable), and all other specimens were classified as unknown. Participants must have been classified as PD-L1 >=5% or PD-L1 <5% per a verified IHC assay, or as indeterminate (ie not unknown), in order to be randomized.

All randomized participants with evaluable PD-L1 expression level at baseline

OS was defined as the time between the date of randomization and the date of death. For participants without documentation of death, OS was censored on the last date the participant was known to be alive.

All randomized participants with evaluable PD-L1 expression level at baseline

Health Related Quality of Life was assessed using the EORTC QLQ-C30 questionnaire Version 3. With the exception of 2 items included in the global health/quality of life scale, for which responses range from 1 (Very poor) to 7 (Excellent), item responses range from 1 (Not at all) to 4 (Very much). Raw scores for the EORTC QLQ-C30 are transformed to a 0-100 metric such that higher scores for all functional scales and Global Health Status indicate better HRQoL; an increase from baseline indicates improvement in HRQoL compared to baseline.

All randomized participants. Only participants with evaluable EORTC scores at baseline and at particular timepoint are considered in the analysis.

Health Related Quality of Life was assessed using the EORTC QLQ-C30 questionnaire Version 3. With the exception of 2 items included in the global health/quality of life scale, for which responses range from 1 (Very poor) to 7 (Excellent), item responses range from 1 (Not at all) to 4 (Very much). Raw scores for the EORTC QLQ-C30 are transformed to a 0-100 metric such that higher scores for all functional scales and Global Health Status indicate better HRQoL; an increase from baseline indicates improvement in HRQoL compared to baseline.

All randomized participants. Only participants with evaluable EORTC scores at baseline and at particular timepoint are considered in the analysis.

Health Related Quality of Life was assessed using the EORTC QLQ-C30 questionnaire Version 3. With the exception of 2 items included in the global health/quality of life scale, for which responses range from 1 (Very poor) to 7 (Excellent), item responses range from 1 (Not at all) to 4 (Very much). Raw scores for the EORTC QLQ-C30 are transformed to a 0-100 metric such that higher scores for all functional scales and Global Health Status indicate better HRQoL; an increase from baseline indicates improvement in HRQoL compared to baseline.

All randomized participants. Only participants with evaluable EORTC scores at baseline and at particular timepoint are considered in the analysis.

Health Related Quality of Life was assessed using the EORTC QLQ-C30 questionnaire Version 3. With the exception of 2 items included in the global health/quality of life scale, for which responses range from 1 (Very poor) to 7 (Excellent), item responses range from 1 (Not at all) to 4 (Very much). Raw scores for the EORTC QLQ-C30 are transformed to a 0-100 metric such that higher scores for all functional scales and Global Health Status indicate better HRQoL; an increase from baseline indicates improvement in HRQoL compared to baseline.

All randomized participants. Only participants with evaluable EORTC scores at baseline and at particular timepoint are considered in the analysis.

Health Related Quality of Life was assessed using the EORTC QLQ-C30 questionnaire Version 3. With the exception of 2 items included in the global health/quality of life scale, for which responses range from 1 (Very poor) to 7 (Excellent), item responses range from 1 (Not at all) to 4 (Very much). Raw scores for the EORTC QLQ-C30 are transformed to a 0-100 metric such that higher scores for all functional scales and Global Health Status indicate better HRQoL; an increase from baseline indicates improvement in HRQoL compared to baseline.

All randomized participants. Only participants with evaluable EORTC scores at baseline and at particular timepoint are considered in the analysis.

Health Related Quality of Life was assessed using the EORTC QLQ-C30 questionnaire Version 3. With the exception of 2 items included in the global health/quality of life scale, for which responses range from 1 (Very poor) to 7 (Excellent), item responses range from 1 (Not at all) to 4 (Very much). Raw scores for the EORTC QLQ-C30 are transformed to a 0-100 metric such that higher scores for all functional scales and Global Health Status indicate better HRQoL; an increase from baseline indicates improvement in HRQoL compared to baseline.

All randomized participants. Only participants with evaluable EORTC scores at baseline and at particular timepoint are considered in the analysis.