A Study to Compare Efficacy, Safety, and Immunogenicity of GME751 and EU-authorized Keytruda in Adult Participants With Untreated Metastatic Non-squamous Non-small Cell Lung Cancer (NSCLC)

Inclusion Criteria:

* At least 18 years of age
* Untreated metastatic NSCLC
* Absence of tumor activating EGFR mutations and absence of ALK gene rearrangements
* Measurable disease according to RECIST 1.1
* Adequate organ function
* Eastern Cooperative Oncology Group (ECOG) performance status score of 0 or 1

Exclusion Criteria:

* Squamous cell or mixed histology in NSCLC
* Known history of hypersensitivity (grade ≥3) to pembrolizumab, chemotherapy or their excipients
* Active autoimmune disease that has required chronic systemic treatment in the past 2 years.
* Received live vaccine ≤30 days before the first study treatment
* Prior treatment with pembrolizumab or any other anti-PD-1, or anti-PD-L1 or anti-PD-L2, or anti-CTLA-4 agent or any antibody targeting other immune-regulatory receptors or mechanisms for lung cancer.

Other protocol-defined inclusion/exclusion criteria apply.