p<0.001) and 45% lower probability of death (HR¼0.549, 95%CI 0.445-0.678, p<0.001) as compared to those with ALI<18, independent of Performance Status, stage at diagnosis, line of treatment and level of PD-L1 expression. There was no statistically significant correlation of ALI with objective response rates to immunotherapy (PD vs CR or PR or SD, p¼0.623).Conclusions: ALI score correlates with clinical benefit from immunotherapy in advanced NSCLC independent from significant co-variables and may assist decisionmaking in clinical practice. Further validation of its value as a predictive marker of immunotherapy efficacy is ongoing.Legal entity responsible for the study: The authors.

Background: KRAS is the most frequently mutated isoform of the rat sarcoma protooncogene in NSCLC. The G12C mutation accounts for w40% of KRAS mutations and occurs in w13% of lung adenocarcinoma. The purpose of this largest US-based cohort study reported to date is to provide real-world evidence on clinicopathological characteristics and treatment patterns in NSCLC KRAS G12C patients in the FH-FMI CGDB.Methods: We performed a retrospective study of adult advanced NSCLC patients who were treated in the Flatiron Health network between January 2011eMarch 2019 with a KRAS G12C mutation detected via FoundationOneÒ tumor sequencing as part of routine, real-world care. Genomic alterations were detected via next-generation sequencing (NGS). Clinicopathological characteristics and treatment patterns were described using de-identified EHR data.Results: 743 advanced NSCLC KRAS G12C patients were identified; 61.1% were female, and the average age (SD) was 67.1 (9.6) years. The majority (97%) were former or current smokers. 69% had advanced or metastatic cancer at initial diagnosis; nonsquamous cell carcinoma (91%) was the most common histology. In the advanced or metastatic setting, 149 (20%) received no therapy, 594 (80%) had at least one line, 301 (41%) had at least two lines, and 151 (20%) had three or more lines of therapy. Limiting to patients with NGS testing prior to or up to 21 days after the start of a line, the most common treatments were platinum-based therapies with/without PD-1/PD-L1 therapy and PD-1/PD-L1 monotherapy in first-line (69% and 25%, respectively) and second-line patients (19% and 58%, respectively). Over 94% of these patients were treated in 2015 or later.Conclusions: This is the largest observational study characterizing NSCLC patients with KRAS G12C mutations. One in five patients did not receive any systemic therapy, and of those treated, platinum-based therapies and PD-1/PD-L1i therapies were commonly used, consistent with treatment patterns expected in these patients. Survival and co-mutation data will be presented.Legal entity responsible for the study: Amgen Inc.

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