Co-mutational status and PD-L1 expression in KRAS mutant non-small cell lung cancer (NSCLC): Role in treatment selection and association with clinical outcomes.

Abstract

9038 Background: In NSCLC, different KRAS mutations (mt) define unique subgroups and certain co-mutations (co-mt) could have prognostic and therapeutic implications. Retrospective studies associate poor prognosis with co-mts in STK11 and KEAP1 with KRAS. It is unclear if PD-L1 expression and co-mt in KRAS mt NSCLC impacts outcomes. Methods: Molecular profiles of 27748 NSCLC tumors were tested with next-generation sequencing (Caris Life Sciences, Phoenix, AZ) and classified by KRAS mt. PD-L1 IHC (22C3) was reported as TPS. Real-world post-immunotherapy (IO) overall survival (OS) was obtained from insurance claims and calculated from start of an immune check-point inhibitor (with or without chemotherapy) to the last day of follow-up. Results: In all, 7634 (28%) samples had a KRAS mt; most common being G12C (11%), G12V (5.3%), G12D (3.9%) and G13X (2.0%). The most frequent co-mt was KRAS-TP53 (KP) (46%), similar in all KRAS subtypes. KRAS-STK11(KL) was in 23% of KRAS mt, enriched in G13X (33%) and lowest in G12D (16%). KRAS-KEAP1(KK) was co-mt in 10% of KRAS mt, highest in G13X (16%) and lowest in G12D (8%). KRASmt/ STK11wt/ KEAP1wt/ TP53wt (K only) was 27% of KRAS mt, highest in G12D (36%) and lowest in G13X (16%). A small subgroup, 5.6% was KRAS-STK11-KEAP1 co-mt (KKL). The majority of pts in the KL (61%), KK (52%) and KKL (62%) cohorts had TPS <1%. In 1723 KRAS mt NSCLC pts treated with IO, KL, KK and KKL had significantly worse post-IO OS than KP and K only (table); KKL had the lowest OS. In the TPS≥1% KRAS mt group, KL, KK and KKL had worse post-IO OS than KP and K-only. In TPS<1% group, KL and KK had poor post-IO OS and K-only had favorable outcomes. However, KP had worse post-IO OS compared to K-only in TPS<1%. In G12C and G12V, similar trend with worse post-IO OS in KL, KK and KKL, compared to KP and K only was noted. Conclusions: We report a large real-world dataset evaluating outcomes with check-point inhibitors in NSCLCs with KRAS and specific co-mts. KL, KK and KKL subgroups demonstrate universally poor outcomes in all KRAS subtypes irrespective of PD-L1. Pts with KP co-mts have adverse post-IO outcomes in TPS<1% but favorable in TPS≥1%. TPS score remains a predictive marker of IO outcomes in KP, but not in KL, KK and KKL. These observations emphasize that both PD-L1 and co-mts have a clear association with clinical outcomes in KRAS-mt NSCLC, and must be used in predictive models for individualized therapy. [Table: see text]