Efficacy of Immune Checkpoint Inhibitors in KRAS-Mutant Non-Small Cell Lung Cancer (NSCLC).

KRAS mutation is the most frequent molecular alteration found in advanced NSCLC; it is associated with a poor prognosis without available targeted therapy. Treatment options for NSCLC have been recently enriched by the development of immune checkpoint inhibitors (ICIs), and data about its efficacy in patients with KRAS-mutant NSCLC are discordant. This study assessed the routine efficacy of ICIs in advanced KRAS-mutant NSCLC. In this retrospective study, clinical data were extracted from the medical records of patients with advanced NSCLC treated with ICIs and with available molecular analysis between April 2013 and June 2017. Analysis of programmed death ligand 1 (PD-L1) expression was performed if exploitable tumor material was available. A total of 282 patients with ICI-treated (in the first line or more) advanced NSCLC (all histological subgroups) who were treated with ICIs (anti-programmed death 1, anti-PD-L1, or anti-cytotoxic T-lymphocyte associated protein 4 antibodies), including 162 (57.4%) with KRAS mutation, 27 (9.6%) with other mutations, and 93 (33%) with a wild-type phenotype, were identified. PD-L1 analysis was available for 128 patients (45.4%), of whom 45.3% and 19.5% had PD-L1 expression of 1% or more and 50%, respectively (49.5% and 21.2%, respectively, in the case of the 85 patients with KRAS-mutant NSCLC). No significant difference was seen in terms of objective response rates, progression-free survival, or overall survival between KRAS-mutant NSCLC and other NSCLC. No significant differences in overall survival or progression-free survival were observed between the major KRAS mutation subtypes (G12A, G12C, G12D, G12V, and G13C). In KRAS-mutant NSCLC, unlike in non-KRAS-mutant NSCLC, the efficacy of ICIs is consistently higher, even though not statistically significant, for patients with PD-L1 expression in 1% or more of tumor cells than for those with PD-L1 expression in less than 1% of tumor cells, and this finding is especially true when PD-L1 expression is high (PD-L1 expression ≥50%). For patients with KRAS-mutant NSCLC (all mutational subtypes), the efficacy of ICI is similar to that for patients with other types of NSCLC. PD-L1 expression seems to be more relevant for predicting the efficacy of ICIs in KRAS-mutant NSCLC than it is in other types of NSCLC.

Jeanson A ，Tomasini P ，Souquet-Bressand M ，Brandone N ，Boucekine M ，Grangeon M ，Chaleat S ，Khobta N ，Milia J ，Mhanna L ，Greillier L ，Biemar J ，Nanni I ，Ouafik L ，Garcia S ，Mazières J ，Barlesi F ，Mascaux C ... -  《-》

The superior efficacy of anti-PD-1/PD-L1 immunotherapy in KRAS-mutant non-small cell lung cancer that correlates with an inflammatory phenotype and increased immunogenicity.

Immune checkpoint inhibitors against PD-1/PD-L1 yield improved survival rates of KRAS-mutant NSCLC patients, who conferred a poor prognosis without effective targeted therapy until now. Yet, the underlying association between KRAS mutations and immune responses remains unclear. We performed an integrated analysis of the data from publicly available repositories and from clinical center cohorts to explore the association between KRAS mutation status and tumor immunity-associated features, including PD-L1 expression, CD8+ tumor-infiltrating lymphocytes (TILs) and tumor mutational burden (TMB). Our results revealed that KRAS mutations are correlated with an inflammatory tumor microenvironment and tumor immunogenicity, resulting in superior patient response to PD-1/PD-L1 inhibitors. Meanwhile, three-pool analysis further confirmed that KRAS-mutant NSCLC patients show remarkable clinical benefit from anti-PD-1/PD-L1 immunotherapy. In addition, a KRAS-mutant lung adenocarcinoma mouse model was established to estimate the relative efficacy of anti-PD-L1 monoclonal antibody monotherapy or combination treatment with docetaxel versus docetaxel alone. Most surprisingly, we found that PD-L1 blockade combined with docetaxel did not promote an anti-tumor response. These findings uncover that PD-1/PD-L1 blockade monotherapy may be the optimal therapeutic schedule in NSCLC patients harboring KRAS mutations.

Liu C ，Zheng S ，Jin R ，Wang X ，Wang F ，Zang R ，Xu H ，Lu Z ，Huang J ，Lei Y ，Mao S ，Wang Y ，Feng X ，Sun N ，Wang Y ，He J ... -  《-》

Predictive value of oncogenic driver subtype, programmed death-1 ligand (PD-L1) score, and smoking status on the efficacy of PD-1/PD-L1 inhibitors in patients with oncogene-driven non-small cell lung cancer.

This multicenter, retrospective study explored the value of oncogene driver subtype, programmed death-1 ligand (PD-L1) status, and smoking status for predicting which patients with oncogene-driven non-small cell lung cancer (NSCLC) would benefit from treatment with programmed death-1 (PD-1)/PD-L1 inhibitors. The clinical features, PD-L1 tumor proportion scores, and PD-1/PD-L1 inhibitor (PDi) outcomes (objective response rate and progression-free survival) of patients who had advanced NSCLC with Kirsten rat sarcoma 2 viral oncogene homolog (KRAS) mutations or common, actionable oncogenic drivers were captured. In total, 189 oncogene-positive patients were analyzed. Of these, 104 received a PDi, and 108 had undergone prior PD-L1 testing. The frequency of PD-L1 positivity (≥1%) was higher in patients who had KRAS mutations (P = .031), smokers (P = .006), and non-Asian patients (P = .002). Multivariable analysis indicated that smoking status (P < .001) was the only factor associated significantly with KRAS mutation. The objective response rate to PDi treatment was 16.9% (11 of 65 patients) among smokers (17.3% in the KRAS-mutant and 15.4% in the non-KRAS-mutant smoker subgroups), which was significantly higher than the 0% rate (0 of 26 patients; P = .019) among never-smokers. In subgroup analyses, progression-free survival was influenced by KRAS mutation status (median, 4.57 vs 1.63 months; P = .004), smoking status (4.07 vs 1.73 months; P = .004), PD-L1 positivity (3.8 vs 1.2 months; P = .040), and non-Asian race (3.0 vs 1.97 months; P = .046). In multivariable analysis, only smoking status (P = .008) remained a significant predictor when a PD-L1 level ≥1% was used. However, both smoking status (P = .001) and PD-L1 status (P = .028) were independent predictors when a PD-L1 level ≥50% was used. Among associated clinical features among patients who have NSCLC with oncogenic drivers, smoking status potentially was the most important, easily available predictor of single PDi efficacy.

Ng TL ，Liu Y ，Dimou A ，Patil T ，Aisner DL ，Dong Z ，Jiang T ，Su C ，Wu C ，Ren S ，Zhou C ，Camidge DR ... -  《-》

KRAS-G12D mutation drives immune suppression and the primary resistance of anti-PD-1/PD-L1 immunotherapy in non-small cell lung cancer.

Although immune checkpoint inhibitors (ICIs) against programmed cell death protein 1 (PD-1) and its ligand PD-L1 have demonstrated potency towards treating patients with non-small cell lung carcinoma (NSCLC), the potential association between Kirsten rat sarcoma viral oncogene homolog (KRAS) oncogene substitutions and the efficacy of ICIs remains unclear. In this study, we aimed to find point mutations in the KRAS gene resistant to ICIs and elucidate resistance mechanism. The association between KRAS variant status and the efficacy of ICIs was explored with a clinical cohort (n = 74), and confirmed with a mouse model. In addition, the tumor immune microenvironment (TIME) of KRAS-mutant NSCLC, such as CD8+ tumor-infiltrating lymphocytes (TILs) and PD-L1 level, was investigated. Cell lines expressing classic KRAS substitutions were used to explore signaling pathway activation involved in the formation of TIME. Furthermore, interventions that improved TIME were developed to increase responsiveness to ICIs. We observed the inferior efficacy of ICIs in KRAS-G12D-mutant NSCLC. Based upon transcriptome data and immunostaining results from KRAS-mutant NSCLC, KRAS-G12D point mutation negatively correlated with PD-L1 level and secretion of chemokines CXCL10/CXCL11 that led to a decrease in CD8+ TILs, which in turn yielded an immunosuppressive TIME. The analysis of cell lines overexpressing classic KRAS substitutions further revealed that KRAS-G12D mutation suppressed PD-L1 level via the P70S6K/PI3K/AKT axis and reduced CXCL10/CXCL11 levels by down-regulating high mobility group protein A2 (HMGA2) level. Notably, paclitaxel, a chemotherapeutic agent, upregulated HMGA2 level, and in turn, stimulated the secretion of CXCL10/CXCL11. Moreover, PD-L1 blockade combined with paclitaxel significantly suppressed tumor growth compared with PD-L1 inhibitor monotherapy in a mouse model with KRAS-G12D-mutant lung adenocarcinoma. Further analyses revealed that the combined treatment significantly enhanced the recruitment of CD8+ TILs via the up-regulation of CXCL10/CXCL11 levels. Results of clinical study also revealed the superior efficacy of chemo-immunotherapy in patients with KRAS-G12D-mutant NSCLC compared with ICI monotherapy. Our study elucidated the molecular mechanism by which KRAS-G12D mutation drives immunosuppression and enhances resistance of ICIs in NSCLC. Importantly, our findings demonstrate that ICIs in combination with chemotherapy may be more effective in patients with KRAS-G12D-mutant NSCLC.

Liu C ，Zheng S ，Wang Z ，Wang S ，Wang X ，Yang L ，Xu H ，Cao Z ，Feng X ，Xue Q ，Wang Y ，Sun N ，He J ... -  《Cancer Communications》

A single institution study evaluating outcomes of PD-L1 high KRAS-mutant advanced non-small cell lung cancer (NSCLC) patients treated with first line immune checkpoint inhibitors.

This study aimed to evaluate the impact of KRAS status on the efficacy of first-line immune checkpoint inhibitors (ICI) in patients with advanced non-small cell lung cancer (NSCLC). Patients with advanced incurable or metastatic NSCLC with PD-L1 ≥50% treated with palliative-intent, single-agent PD-1/PD-L1 inhibitors at the Cancer Centre of Southeastern Ontario were included. KRAS mutation status was determined via massively parallel sequencing. Primary study outcome was median overall survival (mOS). Seventy-eight patients (59 non-squamous, 19 squamous) were identified; only non-squamous patients were included in KRAS mutation analyses. Thirty patients (51%) were KRAS-MT (mutant), with G12C (19%), G12V (15%), and G12D (13%) accounting for the most common KRAS mutation subtypes. There was no difference in mOS between KRAS-MT and KRAS-WT (wild-type) patients (12.9 vs. 19.3 months, p = 0.879). There was a non-significant trend towards worse mOS in KRAS G12C patients compared to non-G12C and KRAS-WT patients (11.4 vs. 44.9 vs. 19.3 months, p = 0.772). On multivariable analysis, KRAS-MT status was not associated with mOS (HR 0.901, 95%CI 0.417-1.946, p = 0.791). ECOG≥2 was an independent prognostic factor for worse mOS (HR 2.853, 95%CI 1.237-6.583, p = 0.014). Immune-related adverse events did not differ between KRAS-MT and KRAS-WT groups (48% vs. 52%, p = 1.000). KRAS mutation status did not have a significant impact on ICI efficacy or safety. However, a non-significant trend towards worse survival was noted in patients treated with ICI whose tumours harboured the KRAS G12C variant. This study provides valuable information for comparative analysis in the future.

Kartolo A ，Feilotter H ，Hopman W ，Fung AS ，Robinson A ... -  《-》