TPS8653 Background: The 5-year progression free survival (PFS) rate of patients with metastatic, PD-L1 negative, non-small cell lung cancer (NSCLC) remains poor, ranging from approximately 2% to 10% with standard immunotherapy-based treatment regimens. Based on promising anti-tumor activity in the phase 1 CodeBreaK 101 study, with partial responses observed in 62% (8/13) of PD-L1 negative patients in the first-line setting, we hypothesize that sotorasib plus platinum doublet chemotherapy will demonstrate durable clinical response and improved outcomes in this population. CodeBreaK 202 (NCT05920356) is a global phase 3 randomized study evaluating the efficacy of sotorasib versus pembrolizumab in combination with platinum doublet chemotherapy as first-line treatment for metastatic or locally advanced, PD-L1 negative, KRAS G12C-mutated NSCLC. Methods: Patients will be randomized 1:1 to either sotorasib 960 mg once daily or pembrolizumab administered in combination with carboplatin and pemetrexed for 4 cycles, followed by maintenance treatment with sotorasib or pembrolizumab administered in combination with pemetrexed. Key eligibility criteria include treatment-naïve metastatic or locally advanced stage IIIB/C disease that is not amenable to definitive chemoradiation, PD-L1 <1% expression, presence of KRAS G12C mutation, non-squamous tumor histology, and absence of actionable genomic alterations such as EGFR mutations and ALK rearrangements. Patients with both treated and untreated brain metastases are eligible if clinically asymptomatic. The primary endpoint is PFS per RECIST v1.1 by blinded independent central review (BICR). Key secondary endpoints include overall survival and objective response rate. Exploratory endpoints include intra-cranial PFS per RANO-BM criteria. Approximately 750 patients are planned to be enrolled and recruitment began on November 18, 2023. Contact Amgen Medical Information for more information: medinfo@amgen.com . Clinical trial information: NCT05920356 .