A Study of Subcutaneous (SC) Pembrolizumab Coformulated With Berahyaluronidase Alfa (MK-3475A) vs Intravenous Pembrolizumab in Adult Participants With Metastatic Non-small Cell Lung Cancer (NSCLC) (MK-3475A-D77)-Japan Extension

This study is to assess the pharmacokinetics (PK) and safety of SC pembrolizumab (+) berahyaluronidase alfa vs intravenous (IV) pembrolizumab, administered with chemotherapy in first line treatment of adult Japanese participants with metastatic non-small cell lung cancer. The primary hypotheses of this study are pembrolizumab (+) berahyaluronidase alfa subcutaneous (SC) is noninferior to pembrolizumab IV with respect to PK parameters.

The key inclusion and exclusion criteria include but are not limited to the following: Inclusion Criteria: * Has histologically or cytologically confirmed diagnosis of squamous or non-squamous Non-small Cell Lung Cancer (NSCLC) * Must provide archival tumor tissue sample or newly obtained core, incisional, or excisional biopsy of a tumor lesion not previously irradiated * Has a life expectancy of at least 3 months Exclusion Criteria: * Has a diagnosis of small cell lung cancer or, for mixed tumors, presence of small cell elements * Has received prior systemic anticancer therapy for metastatic NSCLC * Has received prior systemic anticancer therapy including investigational agents within 4 weeks before randomization * Has received prior radiotherapy within 2 weeks of start of study intervention or has radiation-related toxicity requiring corticosteroids * Has received radiation therapy to the lung (\>30 Gray) within 6 months of start of study intervention * Has received a live or live-attenuated vaccine within 30 days before the first dose of study intervention * Has a diagnosis of immunodeficiency or is receiving chronic systemic steroid therapy * Has a known additional malignancy that is progressing or has required active treatment within the past 3 years * Has an active autoimmune disease that has required systemic treatment in past 2 years * Has an active infection requiring systemic therapy * Has a history of human immunodeficiency virus (HIV) infection * Has a history of Hepatitis B or C * Has not adequately recovered from major surgery or has ongoing surgical complications * Has a history of allogenic tissue/solid organ transplant