A Study of V940 Plus Pembrolizumab (MK-3475) Versus Placebo Plus Pembrolizumab in Participants With Non-small Cell Lung Cancer (V940-002)

Inclusion Criteria:

The main inclusion criteria include but are not limited to the following:

• Has undergone margin negative, completely resected non-small cell lung cancer (NSCLC), and has pathological Stage II, IIIA, IIIB (N2) squamous or nonsquamoustumor, node, metastasis (TNM) staging per American Joint Committee on Cancer (AJCC)Eighth Edition guidelines.

• Has no evidence of disease before randomization.

• Has received at least one dose of adjuvant treatment with standard of care platinumdoublet chemotherapy.

• No more than 24 weeks have elapsed between surgical resection of curative intent andthe first dose of pembrolizumab.

• Participants who are hepatitis B surface antigen (HBsAg) positive are eligible ifthey have received hepatitis B virus (HBV) antiviral therapy for at least 4 weeksand have undetectable HBV viral load prior to randomization.

• Participants with history of hepatitis C virus (HCV) infection are eligible if HCVviral load is undetectable at screening.

• Human immunodeficiency virus (HIV)-infected participants must have well controlledHIV on anti-retroviral therapy (ART).

Exclusion Criteria:

The main exclusion criteria include but are not limited to the following:

• Diagnosis of small cell lung cancer (SCLC) or, for mixed tumors, presence of smallcell elements, or has a neuroendocrine tumor with large cell components or asarcomatoid carcinoma.

• HIV-infected participants with a history of Kaposi's sarcoma and/or MulticentricCastleman's Disease.

• Received prior neoadjuvant therapy for their current NSCLC diagnosis.

• Received or is a candidate to receive radiotherapy for their current NSCLCdiagnosis.

• Received prior therapy with an anti-programmed cell death 1 protein (PD-1),anti-PD-ligand 1 (L1), or anti-PD-L2 agent, or with an agent directed to anotherstimulatory or coinhibitory T-cell receptor.

• Received prior systemic anticancer therapy including investigational agents within 4weeks before randomization.

• Received a live or live-attenuated vaccine within 30 days before the first dose ofstudy intervention. Administration of killed vaccines are allowed.

• Has received an investigational agent or has used an investigational device within 4weeks prior to study intervention administration.

• Diagnosis of immunodeficiency or is receiving chronic systemic steroid therapy (indosing exceeding 10 mg daily of prednisone equivalent) or any other form ofimmunosuppressive therapy within 7 days prior to the first dose of study medication.

• Known additional malignancy that is progressing or has required active treatmentwithin the past 5 years.

• Active autoimmune disease that has required systemic treatment in the past 2 years.Replacement therapy (eg, thyroxine, insulin, or physiologic corticosteroid) isallowed.

• History of (noninfectious) pneumonitis/interstitial lung disease that requiredsteroids or has current pneumonitis/interstitial lung disease.

• Active infection requiring systemic therapy.