A Study Evaluating the Efficacy and Safety of Divarasib and Pembrolizumab Versus Pembrolizumab and Pemetrexed and Carboplatin or Cisplatin in Participants With Previously Untreated, KRAS G12C-Mutated, Advanced or Metastatic Non-Squamous Non-Small Cell Lung Cancer

Eligibility criteria

Inclusion Criteria: • Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1 • Histologically or cytologically confirmed diagnosis of advanced or metastatic non squamous NSCLC that is not eligible for curative surgery and/or definitive chemoradiotherapy • Measurable disease, as defined by RECIST v1.1 • No prior systemic treatment for advanced or metastatic NSCLC • Documentation of the presence of a KRAS G12C mutation • Documentation of known PD-L1 expression status in tumor tissue • Availability of a representative tumor specimen • Adequate end-organ function • Eligible to receive a platinum-based chemotherapy regimen Exclusion Criteria Related to NSCLC: • Known concomitant second oncogenic driver with available targeted treatment • Symptomatic, untreated, or actively progressing central nervous system (CNS) metastases • Spinal cord compression not definitively treated with surgery and/or radiation or previously diagnosed and treated spinal cord compression without evidence that disease has been clinically stable for \>=2 weeks prior to randomization • History of leptomeningeal disease • Uncontrolled tumor-related pain • Uncontrolled pleural effusion, pericardial effusion, or ascites requiring recurrent drainage procedures (once a month or more frequently) Exclusion Criteria Related to Current or Prior Treatments: • Any anti-cancer systemic therapy, including hormonal therapy, within 21 days prior to randomization, or is expected to require any other form of antineoplastic therapy while in the study • Radiation therapy including palliative RT to bone metastases within 2 weeks prior to randomization and RT to the lung \>30Gy within 6 months prior to randomization • Prior treatment with KRAS G12C inhibitors or pan-KRAS/RAS inhibitors • Treatment with systemic immunosuppressive or immunostimulatory medications, including CD137 agonists and immune checkpoint inhibitors • Current treatment with medications that are well known to prolong the QT interval • Treatment with therapeutic oral or IV antibiotics within 2 weeks prior to randomization • Prior allogeneic stem cell or solid organ transplantation Exclusion Criteria Related to General Health: • History of malignancy other than NSCLC within 5 years prior to screening, with the exception of malignancies with a negligible risk of metastasis or death (e.g., 5-year overall survival \[OS\] rate \>90%), such as adequately treated carcinoma in situ of the cervix, non melanoma skin carcinoma, localized prostate cancer, ductal breast carcinoma in situ, or Stage I uterine cancer • Individuals with chronic diarrhea, short bowel syndrome or significant upper gastrointestinal surgery including gastric resection, a history of inflammatory bowel disease (e.g., Crohn's disease or ulcerative colitis) or any active bowel inflammation (including diverticulitis), malabsorption syndrome, conditions that would interfere with enteral absorption • History of idiopathic pulmonary fibrosis, organizing pneumonia (e.g., bronchiolitis obliterans), drug-induced pneumonitis, or idiopathic pneumonitis, or evidence of active pneumonitis on the screening chest computed tomography scan • Significant cardiovascular disease within 3 months prior to screening