Study of REGN 2810 Compared to Platinum-Based Chemotherapies in Participants With Metastatic Non-Small Cell Lung Cancer (NSCLC)

The primary objectives of the study are:

* To compare the overall survival (OS) of cemiplimab versus standard-of-care platinum-based chemotherapies in the first-line treatment of patients with advanced or metastatic non-small cell lung cancer (NSCLC) whose tumors express PD-L1 in ≥50% of tumor cells
* To compare the progression-free survival (PFS) of cemiplimab versus standard-of-care platinum-based chemotherapies in the first-line treatment of patients with advanced or metastatic NSCLC whose tumors express PD-L1 in ≥50% of tumor cells

The key secondary objective of the study is to compare the objective response rate (ORR) of cemiplimab versus platinum-based chemotherapies

There is option to join genomics sub-study.

Eligibility Criteria:
Key Inclusion Criteria:

A patient must meet the following criteria to be eligible for inclusion in the study:

1. Patients with histologically or cytologically documented squamous or non squamous NSCLC with stage IIIB or stage IIIC disease who are not candidates for treatment with definitive concurrent chemoradiation or patients with stage IV disease who received no prior systemic treatment for recurrent or metastatic NSCLC
2. Archival or newly obtained formalin-fixed tumor tissue from a metastatic/recurrent site, which has not previously been irradiated
3. Tumor cells expressing PD L1 above a specific percentage of tumor cells by IHC performed by the central laboratory
4. At least 1 radiographically measureable lesion per RECIST 1.1
5. ECOG performance status of ≤1
6. Anticipated life expectancy of at least 3 months
7. Adequate organ and bone marrow function

Key Exclusion Criteria:

A patient who meets any of the following criteria will be excluded from the study:

1. Patients that have never smoked, defined as smoking \<100 cigarettes in a lifetime
2. Active or untreated brain metastases or spinal cord compression
3. Patients with tumors tested positive for EGFR gene mutations, ALK gene translocations, or ROS1 fusions
4. Encephalitis, meningitis, or uncontrolled seizures in the year prior to randomization
5. History of interstitial lung disease (eg, idiopathic pulmonary fibrosis, organizing pneumonia) or active, noninfectious pneumonitis that required immune-suppressive doses of glucocorticoids to assist with management. A history of radiation pneumonitis in the radiation field is permitted as long as pneumonitis resolved ≥6 months prior to randomization
6. Patients with active, known, or suspected autoimmune disease that has required systemic therapy in the past 2 years
7. Patients with a condition requiring corticosteroid therapy (\>10 mg prednisone/day or equivalent) within 14 days of randomization
8. Another malignancy that is progressing or requires treatment
9. Uncontrolled infection with hepatitis B or hepatitis C or human immunodeficiency virus (HIV) or diagnosis of immunodeficiency
10. Active infection requiring systemic therapy within 14 days prior to randomization
11. Prior therapy with anti-PD 1 or anti-PD L1
12. Treatment-related immune-mediated AEs from immune-modulatory agents
13. Receipt of an investigational drug or device within 30 days
14. Receipt of a live vaccine within 30 days of planned start of study medication
15. Major surgery or significant traumatic injury within 4 weeks prior to first dose
16. Documented allergic or acute hypersensitivity reaction attributed to antibody treatments
17. Known psychiatric or substance abuse disorder that would interfere with participation with the requirements of the study, including current use of any illicit drugs
18. Pregnant or breastfeeding women
19. Women of childbearing potential or men who are unwilling to practice highly effective contraception prior to the initial dose/start of the first treatment, during the study, and for at least 6 months after the last dose

Note: Other protocol defined Inclusion/Exclusion criteria apply.