OS was defined as the time between the date of randomization and the date of death. For subjects without documentation of death, OS was censored on the last date the subject 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 subjects without documentation of death, OS was censored on the last date the subject was known to be alive. Rates provided are Kaplan-Meier estimates.

All randomized participants

Investigator assessed ORR was defined as the number of participants whose best objective response (BOR) was a confirmed complete response (CR) or confirmed partial response (PR), as determined by the investigator, divided by the number of randomized participants.

CR= Disappearance of all target lesions. Any pathological lymph nodes (whether target or non-target) must have reduction in short axis to < 10 mm. PR= At least a 30% decrease in the sum of diameters of target lesions, taking as reference the baseline sum diameters.

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. Test stratified by histology (SQ vs NSQ), PD-L1 status at 1% expression level (positive vs negative/unevaluable).

All randomized participants

PFS was defined as the time from randomization to the date of the first documented tumor progression as determined by investigators per RECIST 1.1, or death due to any cause. Clinical deterioration in the absence of unequivocal evidence of progression was not considered progression for purposes of determining PFS. Participants who died without a reported prior progression were considered to have progressed on the date of their death. Participants who did not have disease progression 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 at the randomization date. Participants who started any subsequent anti-cancer therapy (including on-treatment palliative RT of non-target bone lesions, skin lesions or CNS lesions) without a prior reported progression were censored at the last evaluable tumor assessment prior to or on initiation of the subsequent anti-cancer therapy.

All randomized participants

Clinical deterioration in the absence of unequivocal evidence of progression (per RECIST 1.1) is not considered progression for purposes of determining PFS. Participants who die without a reported prior progression will be considered to have progressed on the date of their death. Participants who did not have disease progression or die will be censored on the date of their last evaluable tumor assessment. Participants who did not have any on study tumor assessments and did not die will be censored at the randomization date. Participants who started any subsequent anti-cancer therapy without a prior reported progression will be censored at the last evaluable tumor assessment prior to or on initiation of the subsequent anti-cancer therapy. Six month progression-free survival rate as estimated using the Kaplan-Meier method

All randomized participants

TTF was defined as the minimum of the time from randomization to disease progression (per RECIST 1.1 or clinical), death or last dose date if a participant discontinued from treatment for any reasons other than "maximum clinical benefit" and "administrative reasons by sponsor". TTF was considered as event at the randomization date for participants who were randomized but not treated. TTF was censored at the last dose date for participants who discontinued treatment due to "maximum clinical benefit" or "administrative reasons by sponsor". TTF was censored at the last dose date for participants who continued on treatment without progression or death.

This outcome measure was prespecified in the protocol to only be evaluated through the first Interim Analysis, which occurred in June 2017.

All randomized participants with at least 8 months of follow-up at the time of TTF analysis. The clinical database cutoff date will occur when the first approximately 380 randomized participants will have at least 8-month of follow-up.

A treatment-related Adverse Event (AE) is defined as any new untoward medical occurrence or worsening of a pre-existing medical condition in a clinical investigation participant administered study treatment and is determined to be associated with the study treatment. Adverse events are graded on a scale from 1 to 5, with Grade 1 being mild and asymptomatic; Grade 2 is moderate requiring minimal, local or noninvasive intervention; Grade 3 is severe or medically significant but not immediately life-threatening; Grade 4 events are usually severe enough to require hospitalization; Grade 5 events are fatal.

All treated participants

A treatment-related Serious Adverse Event (SAE) is defined as any untoward medical occurrence that, at any dose results in death, is life-threatening (defined as an event in which the participant was at risk of death at the time of the event; it does not refer to an event which hypothetically might have caused death if it were more severe), requires inpatient hospitalization or causes prolongation of existing hospitalization and is determined to be associated with the study treatment.

All treated participants

Disease-Related Symptom Deterioration Rate is the percentage of participants with >=10 points increase from baseline in Average Symptom Burden Index (ASBI) score at any time between randomization and the timepoints. The Lung Cancer Symptom Scale (LCSS) measures 6 items (loss of appetite, fatigue, coughing, shortness of breath, hemoptysis, pain) and 3 symptom burden items (disease-related functional limitations, quality of life) with responses captured using a 100mm visual analog scale (VAS). Scores range from 0 (highest quality of life) to 100 (worst quality of life) and is derived by dividing the length of the line drawn from the lowest possible response to the patient's response by the length of the VAS and multiplying the result by 100. An ASBI score can be derived as the mean of scores for the 6 symptom-related items with a clinically meaningful change in ASBI score being 10 points and a meaningful deterioration in symptoms is a mean post-baseline score change >= 10 points.

All randomized participants