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)

In this study, participants with programmed cell death ligand 1 (PD-L1)-positive non-small cell lung cancer (NSCLC) will be randomized to receive single agent pembrolizumab for up to 35 treatments or standard of care (SOC) platinum-based chemotherapy (carboplatin + paclitaxel or carboplatin + pemetrexed for 4 to 6 21-day cycles). Participants in the platinum-based chemotherapy arms with non-squamous tumor histologies may receive pemetrexed maintenance therapy after the 4 to 6 cycles of chemotherapy. The primary study hypothesis is that pembrolizumab prolongs overall survival (OS) compared to SOC chemotherapy.