Introduction
Treatment targeting the KRAS p.G12C (G12C) mutation was approved by both the U.S. Food and Drug Administration and the European Medicines Agency in the past year as second line of treatment (LOT2) for advanced non-small-cell lung cancer (aNSCLC). However, the treatment-eligible G12C mutant NSCLC population has not been well characterized, nor has its outcomes with current treatment approaches. The aim of this study was to characterize a nationwide real-world G12C mutant NSCLC population and to estimate its overall survival (OS) in Denmark.

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Methods
Adult aNSCLC patients diagnosed between January 1st, 2018 and October 31st, 2020 were identified in the Danish Lung Cancer Register. The register has captured data on all Danish lung cancer patients since 2003. Additional information was gathered from the following registers: the Danish National Patient Register, the Danish Pathology Register, the Danish Civil Registration System, the Danish National Prescription Register, the Danish Education Register, and the Income Statistics Register.

Results
We identified 6,058 patients with aNSCLC. A total of 36.5% (n=2,214) were tested with next-generation sequencing (NGS) or polymerase chain reaction (PCR) tests for a KRAS mutation prior to LOT1. Among those tested, 40.5% (n=896) were KRAS mutated, 9.3% (n=206) were G12C mutated, and 39.0% (n=864) were KRAS/EGFR/ALK wild-type (Triple WT). Co-mutation with EGFR was present in 11% of G12C-mutated patients. Key characteristics and outcomes are presented in Table 1. TTNT was similar among

Conclusions
This Danish real-world study evaluating aNSCLC patients after the implementation of targeted therapy and immunotherapy showed that patients with a KRAS G12C mutation had a longer OS from LOT1 and LOT2 compared with Triple WT patients. The longer OS observed in patients with KRAS G12C mutant aNSCLC may be driven by higher PD-L1 expression and consequently more frequent use of immunotherapy.