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)

Pembrolizumab-treated participants, who attain a confirmed complete response (CR) or who stop trial treatment after 35 administrations of study medication for reasons other than disease progression or intolerability, may consider stopping trial treatment. These participants may be eligible for re-treatment with pembrolizumab monotherapy after they have experienced radiographic disease according to protocol-defined criteria. Response or progression in the Second Course Phase will not count towards the objective response rate (ORR) and progression free survival (PFS) endpoints in this trial. The global study for MK-3475-042 enrolled 1274 participants. Of the 1274 total participants enrolled in the global study, 92 were also enrolled in the China extension study for MK-3475-042 (NCT03850444).