Large-scale clinico-genomic profile of non-small cell lung cancer with KRAS G12C: Results from LC-SCRUM-Asia study

Abstract

Introduction: KRAS G12C is an oncogenic driver mutation, accounting for approximately 14% of Caucasian patients with non-small cell lung cancer (NSCLC). Recently, several KRAS G12C-targeted drugs have been developed; however, the clinico-genomic characteristics of NSCLC patients with KRAS G12C remain unclear.

Materials and methods: Based on the large-scale prospective lung cancer genomic screening project (LC-SCRUM-Asia) database, the clinico-genomic characteristics and therapeutic outcomes of NSCLC patients with KRAS G12C were evaluated.

Results: From March 2015 to March 2021, 10,023 NSCLC patients were enrolled in LC-SCRUM-Asia. KRAS mutations were detected in 1258 patients (14 %), including G12C in 376 (4.0 %), G12D in 289 (3.1 %) and G12V in 251 (2.7 %). The proportions of males and smokers were higher in patients with KRAS G12C than in those with KRAS non-G12C mutations (males: 73 % vs 63 %, p < 0.001; smokers: 89 % vs 76 %, p < 0.001). KRAS G12C-positive tumors showed a higher tumor mutation burden (TMB) (mean, 8.1 mut/Mb, p < 0.001) and a higher percentage of tumors with programmed cell death ligand-1 (PD-L1) expression ≥50 % (52 %, p = 0.08). The overall survival in patients with KRAS G12C (median, 24.6 months) was not different between patients with other mutation subtypes (G12V: 18.2 months, p = 0.23; G12D: 20.6 months, p = 0.65; other KRAS mutations: 18.3 months, p = 0.20). Among KRAS-mutated patients who received immune checkpoint inhibitors (ICIs), the progression-free survival in G12C-positive patients (median, 3.4 months) was similar to that in G12V-positive patients (4.2 months, p = 0.90), but significantly longer than that in G12D- (2.0 months, p = 0.02) and other KRAS mutation-positive patients (2.5 months, p = 0.02).

Conclusions: The frequencies of KRAS G12C were lower in Asian than in Caucasian NSCLC patients. Among the KRAS-mutated NSCLC patients, G12C-positive tumors showed increased immunogenicity, such as high TMB and high PD-L1 expression, and potential sensitivity to ICIs.

Keywords: KRAS G12C; KRAS mutation; Next-generation sequencing; Non-small cell lung cancer; PD-L1 expression; Tumor burden.