Trial Outcomes & Findings for Study of Pembrolizumab (MK-3475) Versus Platinum-Based Chemotherapy for Participants With Programmed Cell Death-Ligand 1 (PD-L1)-Positive Advanced or Metastatic Non-Small Cell Lung Cancer (MK-3475-042/KEYNOTE-042)-China Extension Study (NCT NCT03850444)

Last Updated: 2023-09-18

Results Overview

OS was determined for participants with a TPS of ≥50% and was defined as the time from randomization until death due to any cause. Participants without documented death at the time of the analysis were censored at the date of the last follow-up. The OS was calculated using the product-limit (Kaplan-Meier) method for censored data. The OS for participants with a TPS ≥50% is presented.

Recruitment status

COMPLETED

Study phase

PHASE3

Target enrollment

262 participants

Primary outcome timeframe

Up to 23.2 months

Results posted on

2023-09-18

Participant Flow

The China extension study enrolled 262 participants. Of the 262 total participants enrolled, 92 were previously enrolled in the global study for MK-3475-042 (NCT02220894).

Participant milestones

Participant milestones
Measure	Pembrolizumab Participants received pembrolizumab 200 mg by IV infusion on Day 1 every 3 weeks (Q3W) for a maximum of 35 cycles (21-day cycles). Participants who stopped the initial course of pembrolizumab due to complete response or had completed the initial course of pembrolizumab and had stable disease, but progressed after discontinuation, were eligible for a second course of pembrolizumab for up to an additional 1 year (17 additional 21-day cycles).	Chemotherapy (SOC Treatment) Participants received carboplatin at target dose Area Under the Curve (AUC 5) (maximum dose 750 mg) or AUC 6 (maximum dose 900 mg) + paclitaxel 200 mg/m\^2 by IV infusion on Day 1 Q3W for a maximum of 6 cycles (21-day cycles) OR carboplatin target dose AUC 5 (maximum dose 750 mg) or AUC 6 (maximum dose 900 mg) + pemetrexed 500 mg/m\^2 by IV infusion on Day 1 Q3W for a maximum of 6 cycles (21-day cycles). Participants with non-squamous histologies received optional additional maintenance treatment with pemetrexed 500 mg/m\^2 by IV infusion on Day 1 Q3W.
Overall Study STARTED	128	134
Overall Study Treated	128	125
Overall Study Received Second Course of Pembrolizumab	5	0
Overall Study COMPLETED	0	0
Overall Study NOT COMPLETED	128	134

Reasons for withdrawal

Reasons for withdrawal
Measure	Pembrolizumab Participants received pembrolizumab 200 mg by IV infusion on Day 1 every 3 weeks (Q3W) for a maximum of 35 cycles (21-day cycles). Participants who stopped the initial course of pembrolizumab due to complete response or had completed the initial course of pembrolizumab and had stable disease, but progressed after discontinuation, were eligible for a second course of pembrolizumab for up to an additional 1 year (17 additional 21-day cycles).	Chemotherapy (SOC Treatment) Participants received carboplatin at target dose Area Under the Curve (AUC 5) (maximum dose 750 mg) or AUC 6 (maximum dose 900 mg) + paclitaxel 200 mg/m\^2 by IV infusion on Day 1 Q3W for a maximum of 6 cycles (21-day cycles) OR carboplatin target dose AUC 5 (maximum dose 750 mg) or AUC 6 (maximum dose 900 mg) + pemetrexed 500 mg/m\^2 by IV infusion on Day 1 Q3W for a maximum of 6 cycles (21-day cycles). Participants with non-squamous histologies received optional additional maintenance treatment with pemetrexed 500 mg/m\^2 by IV infusion on Day 1 Q3W.
Overall Study Adverse Event	16	10
Overall Study Death	87	107
Overall Study Lost to Follow-up	1	1
Overall Study Withdrawal by Subject	1	5
Overall Study Participation in study terminated by Sponsor	23	11

Baseline Characteristics

Study of Pembrolizumab (MK-3475) Versus Platinum-Based Chemotherapy for Participants With Programmed Cell Death-Ligand 1 (PD-L1)-Positive Advanced or Metastatic Non-Small Cell Lung Cancer (MK-3475-042/KEYNOTE-042)-China Extension Study

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure	Pembrolizumab n=128 Participants Participants received pembrolizumab 200 mg by IV infusion on Day 1 every 3 weeks (Q3W) for a maximum of 35 cycles (21-day cycles). Participants who stopped the initial course of pembrolizumab due to complete response or had completed the initial course of pembrolizumab and had stable disease, but progressed after discontinuation, were eligible for a second course of pembrolizumab for up to an additional 1 year (17 additional 21-day cycles).	Chemotherapy (SOC Treatment) n=134 Participants Participants received carboplatin at target dose Area Under the Curve (AUC 5) (maximum dose 750 mg) or AUC 6 (maximum dose 900 mg) + paclitaxel 200 mg/m\^2 by IV infusion on Day 1 Q3W for a maximum of 6 cycles (21-day cycles) OR carboplatin target dose AUC 5 (maximum dose 750 mg) or AUC 6 (maximum dose 900 mg) + pemetrexed 500 mg/m\^2 by IV infusion on Day 1 Q3W for a maximum of 6 cycles (21-day cycles). Participants with non-squamous histologies received optional additional maintenance treatment with pemetrexed 500 mg/m\^2 by IV infusion on Day 1 Q3W.	Total n=262 Participants Total of all reporting groups
Age, Continuous	60.9 Years STANDARD_DEVIATION 8.1 • n=5 Participants	61.5 Years STANDARD_DEVIATION 8.0 • n=7 Participants	61.2 Years STANDARD_DEVIATION 8.1 • n=5 Participants
Sex: Female, Male Female	23 Participants n=5 Participants	15 Participants n=7 Participants	38 Participants n=5 Participants
Sex: Female, Male Male	105 Participants n=5 Participants	119 Participants n=7 Participants	224 Participants n=5 Participants
Ethnicity (NIH/OMB) Hispanic or Latino	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants
Ethnicity (NIH/OMB) Not Hispanic or Latino	128 Participants n=5 Participants	134 Participants n=7 Participants	262 Participants n=5 Participants
Ethnicity (NIH/OMB) Unknown or Not Reported	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants
Race (NIH/OMB) American Indian or Alaska Native	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants
Race (NIH/OMB) Asian	128 Participants n=5 Participants	134 Participants n=7 Participants	262 Participants n=5 Participants
Race (NIH/OMB) Native Hawaiian or Other Pacific Islander	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants
Race (NIH/OMB) Black or African American	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants
Race (NIH/OMB) White	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants
Race (NIH/OMB) More than one race	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants
Race (NIH/OMB) Unknown or Not Reported	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants
Eastern Cooperative Oncology Group (ECOG) Performance Status (PS) ECOG PS=0	31 Participants n=5 Participants	29 Participants n=7 Participants	60 Participants n=5 Participants
Eastern Cooperative Oncology Group (ECOG) Performance Status (PS) ECOG PS=1	97 Participants n=5 Participants	105 Participants n=7 Participants	202 Participants n=5 Participants
Programmed Cell Death-Ligand 1 (PD-L1) Tumor Expression Status TPS=≥50%	72 Participants n=5 Participants	74 Participants n=7 Participants	146 Participants n=5 Participants
Programmed Cell Death-Ligand 1 (PD-L1) Tumor Expression Status TPS=20-49%	29 Participants n=5 Participants	29 Participants n=7 Participants	58 Participants n=5 Participants
Programmed Cell Death-Ligand 1 (PD-L1) Tumor Expression Status TPS=1-19%	27 Participants n=5 Participants	31 Participants n=7 Participants	58 Participants n=5 Participants
Programmed Cell Death-Ligand 1 (PD-L1) Tumor Expression Status TPS=<1%	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants
Tumor Histology Squamous	71 Participants n=5 Participants	76 Participants n=7 Participants	147 Participants n=5 Participants
Tumor Histology Non-squamous	57 Participants n=5 Participants	58 Participants n=7 Participants	115 Participants n=5 Participants

PRIMARY outcome

Timeframe: Up to 23.2 months

Population: The analysis population included all participants who were alive at the time of randomization and had a TPS of ≥50%.

Outcome measures

Outcome measures
Measure	Pembrolizumab n=72 Participants Participants received pembrolizumab 200 mg by IV infusion on Day 1 every 3 weeks (Q3W) for a maximum of 35 cycles (21-day cycles). Participants who stopped the initial course of pembrolizumab due to complete response or had completed the initial course of pembrolizumab and had stable disease, but progressed after discontinuation, were eligible for a second course of pembrolizumab for up to an additional 1 year (17 additional 21-day cycles).	Chemotherapy (SOC Treatment) n=74 Participants Participants received carboplatin at target dose Area Under the Curve (AUC 5) (maximum dose 750 mg) or AUC 6 (maximum dose 900 mg) + paclitaxel 200 mg/m\^2 by IV infusion on Day 1 Q3W for a maximum of 6 cycles (21-day cycles) OR carboplatin target dose AUC 5 (maximum dose 750 mg) or AUC 6 (maximum dose 900 mg) + pemetrexed 500 mg/m\^2 by IV infusion on Day 1 Q3W for a maximum of 6 cycles (21-day cycles). Participants with non-squamous histologies received optional additional maintenance treatment with pemetrexed 500 mg/m\^2 by IV infusion on Day 1 Q3W.
Overall Survival (OS) in Participants With a Tumor Proportion Score (TPS) of ≥50%	20.0 Months Interval 15.5 to NA = upper limit not reached at time of data cut-off due to insufficient number of participants with an event.	14.0 Months Interval 10.0 to 17.9

PRIMARY outcome

Timeframe: Up to 23.2 months

Population: The analysis population included all participants who were alive at the time of randomization and had a TPS of ≥20%.

OS was determined for participants with a TPS of ≥20% and was defined as the time from randomization until death due to any cause. Participants without documented death at the time of the analysis were censored at the date of the last follow-up. The OS was calculated using the product-limit (Kaplan-Meier) method for censored data. The OS for participants with a TPS ≥20% is presented.

Outcome measures

Outcome measures
Measure	Pembrolizumab n=101 Participants Participants received pembrolizumab 200 mg by IV infusion on Day 1 every 3 weeks (Q3W) for a maximum of 35 cycles (21-day cycles). Participants who stopped the initial course of pembrolizumab due to complete response or had completed the initial course of pembrolizumab and had stable disease, but progressed after discontinuation, were eligible for a second course of pembrolizumab for up to an additional 1 year (17 additional 21-day cycles).	Chemotherapy (SOC Treatment) n=103 Participants Participants received carboplatin at target dose Area Under the Curve (AUC 5) (maximum dose 750 mg) or AUC 6 (maximum dose 900 mg) + paclitaxel 200 mg/m\^2 by IV infusion on Day 1 Q3W for a maximum of 6 cycles (21-day cycles) OR carboplatin target dose AUC 5 (maximum dose 750 mg) or AUC 6 (maximum dose 900 mg) + pemetrexed 500 mg/m\^2 by IV infusion on Day 1 Q3W for a maximum of 6 cycles (21-day cycles). Participants with non-squamous histologies received optional additional maintenance treatment with pemetrexed 500 mg/m\^2 by IV infusion on Day 1 Q3W.
Overall Survival (OS) in Participants With a Tumor Proportion Score (TPS) of ≥20%	20.0 Months Interval 17.4 to NA = upper limit not reached at time of data cut-off due to insufficient number of participants with an event.	13.7 Months Interval 10.1 to 17.9

PRIMARY outcome

Timeframe: Up to 23.2 months

Population: The analysis population included all participants who were alive at the time of randomization and had a TPS of ≥1%.

OS was determined for participants with a TPS of ≥1% and was defined as the time from randomization until death due to any cause. Participants without documented death at the time of the analysis were censored at the date of the last follow-up. The OS was calculated using the product-limit (Kaplan-Meier) method for censored data. The OS for participants with a TPS ≥1% is presented.

Outcome measures

Outcome measures
Measure	Pembrolizumab n=128 Participants Participants received pembrolizumab 200 mg by IV infusion on Day 1 every 3 weeks (Q3W) for a maximum of 35 cycles (21-day cycles). Participants who stopped the initial course of pembrolizumab due to complete response or had completed the initial course of pembrolizumab and had stable disease, but progressed after discontinuation, were eligible for a second course of pembrolizumab for up to an additional 1 year (17 additional 21-day cycles).	Chemotherapy (SOC Treatment) n=134 Participants Participants received carboplatin at target dose Area Under the Curve (AUC 5) (maximum dose 750 mg) or AUC 6 (maximum dose 900 mg) + paclitaxel 200 mg/m\^2 by IV infusion on Day 1 Q3W for a maximum of 6 cycles (21-day cycles) OR carboplatin target dose AUC 5 (maximum dose 750 mg) or AUC 6 (maximum dose 900 mg) + pemetrexed 500 mg/m\^2 by IV infusion on Day 1 Q3W for a maximum of 6 cycles (21-day cycles). Participants with non-squamous histologies received optional additional maintenance treatment with pemetrexed 500 mg/m\^2 by IV infusion on Day 1 Q3W.
Overall Survival (OS) in Participants With a Tumor Proportion Score (TPS) of ≥1%	20.0 Months Interval 17.4 to NA = upper limit not reached at time of data cut-off due to insufficient number of participants with an event.	13.7 Months Interval 10.1 to 17.9

SECONDARY outcome

Timeframe: Up to 23.2 months

Population: The analysis population included all participants who were alive at the time of randomization and had a TPS of ≥50%.

PFS was determined for participants with a TPS of ≥50% and was defined as the time from randomization until the first documented progressive disease (PD) or death due to any cause, whichever occurred first. Per RECIST 1.1, PD was defined as ≥20% increase in the sum of diameters of target lesions, taking as reference the smallest sum on study. In addition to the relative increase of 20%, the sum must also demonstrate an absolute increase of ≥5 mm. The appearance of one or more new lesions or progression in non-target lesions was also considered PD. The PFS per RECIST 1.1 was calculated using the product-limit (Kaplan-Meier) method for censored data. The PFS for participants with a TPS ≥50% is presented.

Outcome measures

Outcome measures
Measure	Pembrolizumab n=72 Participants Participants received pembrolizumab 200 mg by IV infusion on Day 1 every 3 weeks (Q3W) for a maximum of 35 cycles (21-day cycles). Participants who stopped the initial course of pembrolizumab due to complete response or had completed the initial course of pembrolizumab and had stable disease, but progressed after discontinuation, were eligible for a second course of pembrolizumab for up to an additional 1 year (17 additional 21-day cycles).	Chemotherapy (SOC Treatment) n=74 Participants Participants received carboplatin at target dose Area Under the Curve (AUC 5) (maximum dose 750 mg) or AUC 6 (maximum dose 900 mg) + paclitaxel 200 mg/m\^2 by IV infusion on Day 1 Q3W for a maximum of 6 cycles (21-day cycles) OR carboplatin target dose AUC 5 (maximum dose 750 mg) or AUC 6 (maximum dose 900 mg) + pemetrexed 500 mg/m\^2 by IV infusion on Day 1 Q3W for a maximum of 6 cycles (21-day cycles). Participants with non-squamous histologies received optional additional maintenance treatment with pemetrexed 500 mg/m\^2 by IV infusion on Day 1 Q3W.
Progression-Free Survival (PFS) Per Response Evaluation Criteria in Solid Tumors Version 1.1 (RECIST 1.1) as Assessed by Blinded Independent Central Review (BICR) in Participants With a Tumor Proportion Score (TPS) of ≥50%	8.3 Months Interval 4.2 to 10.6	6.5 Months Interval 4.4 to 9.1

SECONDARY outcome

Timeframe: Up to 23.2 months

Population: The analysis population included all participants who were alive at the time of randomization and had a TPS of ≥20%.

PFS was determined for participants with a TPS of ≥20% and was defined as the time from randomization until the first documented progressive disease (PD) or death due to any cause, whichever occurred first. Per RECIST 1.1, PD was defined as ≥20% increase in the sum of diameters of target lesions, taking as reference the smallest sum on study. In addition to the relative increase of 20%, the sum must also demonstrate an absolute increase of ≥5 mm. The appearance of one or more new lesions or progression in non-target lesions was also considered PD. The PFS per RECIST 1.1 was calculated using the product-limit (Kaplan-Meier) method for censored data. The PFS for participants with a TPS ≥20% is presented.

Outcome measures

Outcome measures
Measure	Pembrolizumab n=101 Participants Participants received pembrolizumab 200 mg by IV infusion on Day 1 every 3 weeks (Q3W) for a maximum of 35 cycles (21-day cycles). Participants who stopped the initial course of pembrolizumab due to complete response or had completed the initial course of pembrolizumab and had stable disease, but progressed after discontinuation, were eligible for a second course of pembrolizumab for up to an additional 1 year (17 additional 21-day cycles).	Chemotherapy (SOC Treatment) n=103 Participants Participants received carboplatin at target dose Area Under the Curve (AUC 5) (maximum dose 750 mg) or AUC 6 (maximum dose 900 mg) + paclitaxel 200 mg/m\^2 by IV infusion on Day 1 Q3W for a maximum of 6 cycles (21-day cycles) OR carboplatin target dose AUC 5 (maximum dose 750 mg) or AUC 6 (maximum dose 900 mg) + pemetrexed 500 mg/m\^2 by IV infusion on Day 1 Q3W for a maximum of 6 cycles (21-day cycles). Participants with non-squamous histologies received optional additional maintenance treatment with pemetrexed 500 mg/m\^2 by IV infusion on Day 1 Q3W.
Progression-Free Survival (PFS) Per Response Evaluation Criteria in Solid Tumors Version 1.1 (RECIST 1.1) as Assessed by Blinded Independent Central Review (BICR) in Participants With a Tumor Proportion Score (TPS) of ≥20%	6.3 Months Interval 4.2 to 8.4	6.5 Months Interval 5.9 to 8.5

SECONDARY outcome

Timeframe: Up to 23.2 months

Population: The analysis population included all participants who were alive at the time of randomization and had a TPS of ≥1%.

PFS was determined for participants with a TPS of ≥1% and was defined as the time from randomization until the first documented progressive disease (PD) or death due to any cause, whichever occurred first. Per RECIST 1.1, PD was defined as ≥20% increase in the sum of diameters of target lesions, taking as reference the smallest sum on study. In addition to the relative increase of 20%, the sum must also demonstrate an absolute increase of ≥5 mm. The appearance of one or more new lesions or progression in non-target lesions was also considered PD. The PFS per RECIST 1.1 was calculated using the product-limit (Kaplan-Meier) method for censored data. The PFS for participants with a TPS ≥1% is presented.

Outcome measures

Outcome measures
Measure	Pembrolizumab n=128 Participants Participants received pembrolizumab 200 mg by IV infusion on Day 1 every 3 weeks (Q3W) for a maximum of 35 cycles (21-day cycles). Participants who stopped the initial course of pembrolizumab due to complete response or had completed the initial course of pembrolizumab and had stable disease, but progressed after discontinuation, were eligible for a second course of pembrolizumab for up to an additional 1 year (17 additional 21-day cycles).	Chemotherapy (SOC Treatment) n=134 Participants Participants received carboplatin at target dose Area Under the Curve (AUC 5) (maximum dose 750 mg) or AUC 6 (maximum dose 900 mg) + paclitaxel 200 mg/m\^2 by IV infusion on Day 1 Q3W for a maximum of 6 cycles (21-day cycles) OR carboplatin target dose AUC 5 (maximum dose 750 mg) or AUC 6 (maximum dose 900 mg) + pemetrexed 500 mg/m\^2 by IV infusion on Day 1 Q3W for a maximum of 6 cycles (21-day cycles). Participants with non-squamous histologies received optional additional maintenance treatment with pemetrexed 500 mg/m\^2 by IV infusion on Day 1 Q3W.
Progression-Free Survival (PFS) Per Response Evaluation Criteria in Solid Tumors Version 1.1 (RECIST 1.1) as Assessed by Blinded Independent Central Review (BICR) in Participants With a Tumor Proportion Score (TPS) of ≥1%	6.3 Months Interval 4.2 to 8.3	6.4 Months Interval 5.9 to 7.6

SECONDARY outcome

Timeframe: Up to 23.2 months

Population: The analysis population included all participants who were alive at the time of randomization and had a TPS of ≥50%.

ORR was determined for participants with a TPS of ≥50%. ORR was determined per RECIST 1.1 and was defined as the percentage of participants in the analysis population who had a Complete Response (CR: Disappearance of all target and non-target lesions) or a Partial Response (PR: ≥30% decrease in the sum of diameters of target lesions, taking as reference the baseline sum diameters) per RECIST 1.1. The percentage of participants who had a TPS ≥50% and who experienced a CR or PR is presented.

Outcome measures

Outcome measures
Measure	Pembrolizumab n=72 Participants Participants received pembrolizumab 200 mg by IV infusion on Day 1 every 3 weeks (Q3W) for a maximum of 35 cycles (21-day cycles). Participants who stopped the initial course of pembrolizumab due to complete response or had completed the initial course of pembrolizumab and had stable disease, but progressed after discontinuation, were eligible for a second course of pembrolizumab for up to an additional 1 year (17 additional 21-day cycles).	Chemotherapy (SOC Treatment) n=74 Participants Participants received carboplatin at target dose Area Under the Curve (AUC 5) (maximum dose 750 mg) or AUC 6 (maximum dose 900 mg) + paclitaxel 200 mg/m\^2 by IV infusion on Day 1 Q3W for a maximum of 6 cycles (21-day cycles) OR carboplatin target dose AUC 5 (maximum dose 750 mg) or AUC 6 (maximum dose 900 mg) + pemetrexed 500 mg/m\^2 by IV infusion on Day 1 Q3W for a maximum of 6 cycles (21-day cycles). Participants with non-squamous histologies received optional additional maintenance treatment with pemetrexed 500 mg/m\^2 by IV infusion on Day 1 Q3W.
Objective Response Rate (ORR) Per Response Evaluation Criteria in Solid Tumors Version 1.1 (RECIST 1.1) as Assessed by Blinded Independent Central Review (BICR) in Participants With a Tumor Proportion Score (TPS) of ≥50%	41.7 Percentage of participants Interval 30.2 to 53.9	24.3 Percentage of participants Interval 15.1 to 35.7

SECONDARY outcome

Timeframe: Up to 23.2 months

Population: The analysis population included all participants who were alive at the time of randomization and had a TPS of ≥20%.

ORR was determined for participants with a TPS of ≥20%. ORR was determined per RECIST 1.1 and was defined as the percentage of participants in the analysis population who had a Complete Response (CR: Disappearance of all target and non-target lesions) or a Partial Response (PR: ≥30% decrease in the sum of diameters of target lesions, taking as reference the baseline sum diameters) per RECIST 1.1. The percentage of participants who had a TPS ≥20% and who experienced a CR or PR is presented.

Outcome measures

Outcome measures
Measure	Pembrolizumab n=101 Participants Participants received pembrolizumab 200 mg by IV infusion on Day 1 every 3 weeks (Q3W) for a maximum of 35 cycles (21-day cycles). Participants who stopped the initial course of pembrolizumab due to complete response or had completed the initial course of pembrolizumab and had stable disease, but progressed after discontinuation, were eligible for a second course of pembrolizumab for up to an additional 1 year (17 additional 21-day cycles).	Chemotherapy (SOC Treatment) n=103 Participants Participants received carboplatin at target dose Area Under the Curve (AUC 5) (maximum dose 750 mg) or AUC 6 (maximum dose 900 mg) + paclitaxel 200 mg/m\^2 by IV infusion on Day 1 Q3W for a maximum of 6 cycles (21-day cycles) OR carboplatin target dose AUC 5 (maximum dose 750 mg) or AUC 6 (maximum dose 900 mg) + pemetrexed 500 mg/m\^2 by IV infusion on Day 1 Q3W for a maximum of 6 cycles (21-day cycles). Participants with non-squamous histologies received optional additional maintenance treatment with pemetrexed 500 mg/m\^2 by IV infusion on Day 1 Q3W.
Objective Response Rate (ORR) Per Response Evaluation Criteria in Solid Tumors Version 1.1 (RECIST 1.1) as Assessed by Blinded Independent Central Review (BICR) in Participants With a Tumor Proportion Score (TPS) of ≥20%	35.6 Percentage of participants Interval 26.4 to 45.8	24.3 Percentage of participants Interval 16.4 to 33.7

SECONDARY outcome

Timeframe: Up to 23.2 months

Population: The analysis population included all participants who were alive at the time of randomization and had a TPS of ≥1%.

ORR was determined for participants with a TPS of ≥1%. ORR was determined per RECIST 1.1 and was defined as the percentage of participants in the analysis population who had a Complete Response (CR: Disappearance of all target and non-target lesions) or a Partial Response (PR: ≥30% decrease in the sum of diameters of target lesions, taking as reference the baseline sum diameters) per RECIST 1.1. The percentage of participants who had a TPS ≥1% and who experienced a CR or PR is presented.

Outcome measures

Outcome measures
Measure	Pembrolizumab n=128 Participants Participants received pembrolizumab 200 mg by IV infusion on Day 1 every 3 weeks (Q3W) for a maximum of 35 cycles (21-day cycles). Participants who stopped the initial course of pembrolizumab due to complete response or had completed the initial course of pembrolizumab and had stable disease, but progressed after discontinuation, were eligible for a second course of pembrolizumab for up to an additional 1 year (17 additional 21-day cycles).	Chemotherapy (SOC Treatment) n=134 Participants Participants received carboplatin at target dose Area Under the Curve (AUC 5) (maximum dose 750 mg) or AUC 6 (maximum dose 900 mg) + paclitaxel 200 mg/m\^2 by IV infusion on Day 1 Q3W for a maximum of 6 cycles (21-day cycles) OR carboplatin target dose AUC 5 (maximum dose 750 mg) or AUC 6 (maximum dose 900 mg) + pemetrexed 500 mg/m\^2 by IV infusion on Day 1 Q3W for a maximum of 6 cycles (21-day cycles). Participants with non-squamous histologies received optional additional maintenance treatment with pemetrexed 500 mg/m\^2 by IV infusion on Day 1 Q3W.
Objective Response Rate (ORR) Per Response Evaluation Criteria in Solid Tumors Version 1.1 (RECIST 1.1) as Assessed by Blinded Independent Central Review (BICR) in Participants With a Tumor Proportion Score (TPS) of ≥1%	32.8 Percentage of participants Interval 24.8 to 41.7	24.6 Percentage of participants Interval 17.6 to 32.8

SECONDARY outcome

Timeframe: Up to 59.7 months

Population: The analysis population consisted of all participants who received ≥1 dose of study treatment.

An AE was defined as any untoward medical occurrence in a participant administered a study treatment and which does not necessarily have to have a causal relationship with this treatment. An AE could therefore be any unfavorable and unintended sign, symptom, or disease temporally associated with the use of a medicinal product or protocol-specified procedure, whether or not considered related to the study treatment or protocol-specified procedure. Any worsening (i.e., any clinically significant adverse change in frequency and/or intensity) of a pre-existing condition that was temporally associated with the use of study treatment, was also an AE. The number of participants who experienced at least one AE is presented.

Outcome measures

Outcome measures
Measure	Pembrolizumab n=128 Participants Participants received pembrolizumab 200 mg by IV infusion on Day 1 every 3 weeks (Q3W) for a maximum of 35 cycles (21-day cycles). Participants who stopped the initial course of pembrolizumab due to complete response or had completed the initial course of pembrolizumab and had stable disease, but progressed after discontinuation, were eligible for a second course of pembrolizumab for up to an additional 1 year (17 additional 21-day cycles).	Chemotherapy (SOC Treatment) n=125 Participants Participants received carboplatin at target dose Area Under the Curve (AUC 5) (maximum dose 750 mg) or AUC 6 (maximum dose 900 mg) + paclitaxel 200 mg/m\^2 by IV infusion on Day 1 Q3W for a maximum of 6 cycles (21-day cycles) OR carboplatin target dose AUC 5 (maximum dose 750 mg) or AUC 6 (maximum dose 900 mg) + pemetrexed 500 mg/m\^2 by IV infusion on Day 1 Q3W for a maximum of 6 cycles (21-day cycles). Participants with non-squamous histologies received optional additional maintenance treatment with pemetrexed 500 mg/m\^2 by IV infusion on Day 1 Q3W.
Number of Participants Who Experienced At Least One Adverse Event (AE)	126 Participants	124 Participants

SECONDARY outcome

Timeframe: Up to 56.7 months

Population: The analysis population consisted of all participants who received ≥1 dose of study treatment.

Outcome measures

Outcome measures
Measure	Pembrolizumab n=128 Participants Participants received pembrolizumab 200 mg by IV infusion on Day 1 every 3 weeks (Q3W) for a maximum of 35 cycles (21-day cycles). Participants who stopped the initial course of pembrolizumab due to complete response or had completed the initial course of pembrolizumab and had stable disease, but progressed after discontinuation, were eligible for a second course of pembrolizumab for up to an additional 1 year (17 additional 21-day cycles).	Chemotherapy (SOC Treatment) n=125 Participants Participants received carboplatin at target dose Area Under the Curve (AUC 5) (maximum dose 750 mg) or AUC 6 (maximum dose 900 mg) + paclitaxel 200 mg/m\^2 by IV infusion on Day 1 Q3W for a maximum of 6 cycles (21-day cycles) OR carboplatin target dose AUC 5 (maximum dose 750 mg) or AUC 6 (maximum dose 900 mg) + pemetrexed 500 mg/m\^2 by IV infusion on Day 1 Q3W for a maximum of 6 cycles (21-day cycles). Participants with non-squamous histologies received optional additional maintenance treatment with pemetrexed 500 mg/m\^2 by IV infusion on Day 1 Q3W.
Number of Participants Who Discontinued Study Treatment Due to an Adverse Event (AE)	26 Participants	22 Participants

Adverse Events

Pembrolizumab

Serious events: 42 serious events

Other events: 119 other events

Deaths: 99 deaths

Chemotherapy (SOC Treatment)

Serious events: 41 serious events

Other events: 119 other events

Deaths: 117 deaths

Pembrolizumab Second Course

Serious events: 2 serious events

Other events: 5 other events

Deaths: 4 deaths

Serious adverse events

Other adverse events

Additional Information

Senior Vice President, Global Clinical Development

Merck Sharp & Dohme LLC

Phone: 1-800-672-6372

Email: [email protected]

Results disclosure agreements

Principal investigator is a sponsor employee The Sponsor must have the opportunity to review all proposed abstracts, manuscripts or presentations regarding this trial 45 days prior to submission for publication/presentation. Any information identified by the Sponsor as confidential must be deleted prior to submission; this confidentiality does not include efficacy and safety results. Sponsor review can be expedited to meet publication timelines.
Publication restrictions are in place

Restriction type: OTHER