Study of Pembrolizumab/Vibostolimab Coformulation (MK-7684A) in Combination With Chemotherapy Versus Pembrolizumab Plus Chemotherapy in Participants With Metastatic Non-Small Cell Lung Cancer (MK-7684A-007/KEYVIBE-007)

The primary hypothesis is that pembrolizumab/vibostolimab (MK-7684A) in combination with chemotherapy is superior to pembrolizumab in combination with chemotherapy with respect to overall survival (OS) in treatment-naïve metastatic participants with non-small cell lung cancer (NSCLC).

Effective as of Amendment 5, Participants receiving coformulation of pembrolizumab/vibostolimab plus chemotherapy will be transitioned to standard of care (SOC, pembrolizumab plus chemotherapy). Participants with access to approved standard of care (SOC) should be considered for discontinuation from the study. Those benefiting from pembrolizumab plus chemotherapy, but unable to access it as SOC outside the study, may continue on study and receive treatment with pembrolizumab plus chemotherapy until discontinuation criteria are met.

Eligibility Criteria:
The main inclusion and exclusion criteria include but are not limited to the following:

Inclusion Criteria:

* A histologically or cytologically confirmed diagnosis of Stage IV squamous or non-squamous NSCLC
* Has not received prior systemic treatment for metastatic NSCLC
* Has measurable disease based on RECIST 1.1, as determined by the local site assessment
* Has a life expectancy of at least 3 months
* Males: Use contraception unless confirmed to be azoospermic; Females: Women of childbearing potential use highly effective contraceptive method

Exclusion Criteria:

* Known additional malignancy that is progressing or has required active treatment within the past 3 years
* Known active central nervous system (CNS) metastases and/or carcinomatous meningitis
* Severe hypersensitivity to MK-7684, MK-7684A, pembrolizumab, chemotherapy components, and/or any of its excipients
* Diagnosis of immunodeficiency or is receiving chronic systemic steroid therapy (in dosing exceeding 10 mg daily of prednisone equivalent) or any other form of immunosuppressive therapy within 7 days before the first dose of study medication
* Active autoimmune disease that has required systemic treatment in past 2 years, except replacement therapy (eg, thyroxine, insulin, or physiologic corticosteroid)
* History of (noninfectious) pneumonitis/interstitial lung disease that required steroids or has current pneumonitis/interstitial lung disease
* Has an active infection requiring systemic therapy
* Has a known history of human immunodeficiency virus (HIV), Hepatitis B or/and Hepatitis C virus
* Received prior systemic anticancer therapy for metastatic disease
* Received a live or live attenuated vaccine within 30 days before the first dose of study intervention. Administration of killed vaccines are allowed
* History of allogeneic tissue/solid organ transplant
* Is unable to interrupt aspirin or other nonsteroidal anti-inflammatory drugs (NSAIDs), other than an aspirin dose ≤1.3 g/day, for a 5-day period (8-day period for long-acting agents, such as piroxicam)
* Is unable or unwilling to take folic acid or vitamin B12 supplementation
* Currently participating in or has participated in a study of an investigational agent or has used an investigational device within 4 weeks before the first dose of study intervention