Molecular markers of metastatic disease in KRAS-mutant lung adenocarcinoma

BACKGROUND

Prior studies characterized the association of molecular alterations with treatment-specific outcomes in KRAS-mutant (KRASMUT) lung adenocarcinoma (LUAD). Less is known about the prognostic role of molecular alterations and their associations with metastatic disease.

PATIENTS AND METHODS

We analyzed clinicogenomic data from 1817 patients with KRASMUT LUAD sequenced at the Dana-Farber Cancer Institute (DFCI) and Memorial Sloan Kettering Cancer Center (MSKCC). Patients with metastatic (M1) and nonmetastatic (M0) disease were compared. Transcriptomic data from The Cancer Genome Atlas (TCGA) were investigated to characterize the biology of differential associations with clinical outcomes. Organ-specific metastasis was associated with overall survival (OS).

RESULTS

KEAP1 (DFCI: OR = 2.3, q = 0.04; MSKCC: OR = 2.2, q = 0.00027) and SMARCA4 mutations (DFCI: OR = 2.5, q = 0.06; MSKCC: OR = 2.6, q = 0.0021) were enriched in M1 versus M0 tumors. On integrative modeling, NRF2 activation was the genomic feature most associated with OS. KEAP1 mutations were enriched in M1 versus M0 tumors independent of STK11 status (KEAP1MUT/STK11WT: DFCI OR = 3.0, P = 0.0064; MSKCC OR = 2.0, P = 0.041; KEAP1MUT/STK11MUT: DFCI OR = 2.3, P = 0.0063; MSKCC OR = 2.5, P = 3.6 × 10-05); STK11 mutations without KEAP1 loss were not associated with stage (KEAP1WT/STK11MUT: DFCI OR = 0.97, P = 1.0; MSKCC OR = 1.2, P = 0.33) or outcome. KEAP1/KRAS-mutated tumors with and without STK11 mutations exhibited high functional STK11 loss. The negative effects of KEAP1 were compounded in the presence of bone (HR = 2.3, P = 4.4 × 10-14) and negated in the presence of lymph node metastasis (HR = 1.0, P = 0.91).

CONCLUSIONS

Mutations in KEAP1 and SMARCA4, but not STK11, were associated with metastatic disease and poor OS. Functional STK11 loss, however, may contribute to poor outcomes in KEAP1MUT tumors. Integrating molecular data with clinical and metastatic-site annotations can more accurately risk stratify patients.

Dissecting the clinicopathologic, genomic, and immunophenotypic correlates of KRASG12D-mutated non-small-cell lung cancer

BACKGROUND

Allele-specific KRAS inhibitors are an emerging class of cancer therapies. KRAS-mutant (KRASMUT) non-small-cell lung cancers (NSCLCs) exhibit heterogeneous outcomes, driven by differences in underlying biology shaped by co-mutations. In contrast to KRASG12C NSCLC, KRASG12D NSCLC is associated with low/never-smoking status and is largely uncharacterized.

PATIENTS AND METHODS

Clinicopathologic and genomic information were collected from patients with NSCLCs harboring a KRAS mutation at the Dana-Farber Cancer Institute (DFCI), Memorial Sloan Kettering Cancer Center, MD Anderson Cancer Center, and Imperial College of London. Multiplexed immunofluorescence for CK7, programmed cell death protein 1 (PD-1), programmed death-ligand 1 (PD-L1), Foxp3, and CD8 was carried out on a subset of samples with available tissue at the DFCI. Clinical outcomes to PD-(L)1 inhibition ± chemotherapy were analyzed according to KRAS mutation subtype.

RESULTS

Of 2327 patients with KRAS-mutated (KRASMUT) NSCLC, 15% (n = 354) harbored KRASG12D. Compared to KRASnon-G12D NSCLC, KRASG12D NSCLC had a lower pack-year (py) smoking history (median 22.5 py versus 30.0 py, P < 0.0001) and was enriched in never smokers (22% versus 5%, P < 0.0001). KRASG12D had lower PD-L1 tumor proportion score (TPS) (median 1% versus 5%, P < 0.01) and lower tumor mutation burden (TMB) compared to KRASnon-G12D (median 8.4 versus 9.9 mt/Mb, P < 0.0001). Of the samples which underwent multiplexed immunofluorescence, KRASG12D had lower intratumoral and total CD8+PD1+ T cells (P < 0.05). Among 850 patients with advanced KRASMUT NSCLC who received PD-(L)1-based therapies, KRASG12D was associated with a worse objective response rate (ORR) (15.8% versus 28.4%, P = 0.03), progression-free survival (PFS) [hazard ratio (HR) 1.51, 95% confidence interval (CI) 1.45-2.00, P = 0.003], and overall survival (OS; HR 1.45, 1.05-1.99, P = 0.02) to PD-(L)1 inhibition alone but not to chemo-immunotherapy combinations [ORR 30.6% versus 35.7%, P = 0.51; PFS HR 1.28 (95%CI 0.92-1.77), P = 0.13; OS HR 1.36 (95%CI 0.95-1.96), P = 0.09] compared to KRASnon-G12D.

CONCLUSIONS

KRASG12D lung cancers harbor distinct clinical, genomic, and immunologic features compared to other KRAS-mutated lung cancers and worse outcomes to PD-(L)1 blockade. Drug development for KRASG12D lung cancers will have to take these differences into account.

Clinical activity of programmed cell death 1 (PD-1) blockade in never, light, and heavy smokers with non-small-cell lung cancer and PD-L1 expression ≥50

Background:

Immune checkpoint inhibitors (ICIs) are standard therapies for patients with advanced non-small-cell lung cancer (NSCLC) and a programmed death-ligand 1 (PD-L1) tumor proportion score (TPS) ≥50%. Tumor mutation burden (TMB) also predicts response to ICIs but is often not available in real time for decision making in the first-line setting. Smoking exposure can be a proxy for TMB in NSCLC. The impact of smoking status on efficacy of PD-1 blockade in NSCLC patients with PD-L1 TPS ≥50% has not been well defined.

Patients and methods:

To investigate the relationship between smoking and activity of ICIs in NSCLC, we retrospectively studied 315 patients with NSCLC and PD-L1 TPS ≥50% at five USA academic medical centers. Objective response rates (ORRs), progression-free survival (PFS), and duration of response (DOR) were compared between never (<100 lifetime cigarettes), light (≤10 pack-years), and heavy (>10 pack-years) smokers. A subset of patients underwent next-generation sequencing to estimate TMB.

Results:

We identified 36 (11%) never, 42 (13%) light, and 237 (75%) heavy smokers with NSCLC and PD-L1 TPS ≥50% treated with ICIs. Objective responses were observed in 27%, 40%, and 40% of never, light, and heavy smokers, respectively (P = 0.180 never versus heavy; P = 1.000 light versus heavy). Median PFS and median DOR were numerically shorter in never and light smokers compared with heavy smokers (PFS 3.0 versus 4.0 versus 5.4 months; median DOR 6.9 versus 10.8 versus 17.8 months), but were not statistically different [PFS: hazard ratio (HR) 1.37, P = 0.135 and HR 1.24, P = 0.272; DOR: HR 1.92, P = 0.217 and HR 1.79, P = 0.141].

Conclusions:

PD-(L)1 inhibitors are associated with antitumor activity in NSCLC with PD-L1 TPS ≥50% regardless of smoking status. Nevertheless, there is a signal of potentially decreased durability among never and light smokers that should be further evaluated. Distinct immunobiologic features may affect initial response versus durability of antitumor immunity to programmed cell death 1 (PD-1) blockade.