Clinical characteristics and prognostic value of the KRAS G12C mutation in Chinese non-small cell lung cancer patients.

BACKGROUND: The KRAS mutation is the second most common genetic variant in Chinese non-small cell lung cancer (NSCLC) patients. At the 2019th World Conference of Lung Cancer, the KRAS G12C-specific inhibitor AMG510 showed promising results in the phase I clinical trial. However, the frequency, clinical characteristics, and prognostic significance of the KRAS G12C mutation in Chinese NSCLC patients are rarely reported. METHODS: Next-generation sequencing was used to confirm the KRAS mutation status in 40,804 NSCLC patients from multiple centers (mCohort). Survival data were collected retrospectively from 1456 patients at one of the centers, the Guangdong Lung Cancer Institute (iCohort). RESULTS: In the mCohort, 3998 patients (9.8%) were confirmed to harbor a KRAS mutation, of whom 1179 (29.5%) had the G12C subtype. In the iCohort, 130 NSCLC patients (8.9%) had a KRAS mutation and 42 (32.3%) had the G12C subtype. The G12C subgroup included more male patients (85.2% vs 67.4%, P < 0.0001) and more smokers (76.2% vs 53.4%, P = 0.02) than did the non-G12C subgroup. Both the KRAS mutation group and KRAS G12C mutation subgroup were associated with a shorter median overall survival (OS) than wildtype tumors (15.1 vs 26.7 months, hazard ratio [HR] KRAS = 1.50, P = 0.002; 18.3 vs 26.7 months, HR G12C = 1.66, P = 0.007). In Cox regression analysis, smoking (HR = 1.39, P = 0.05) and stage IV disease (HR = 2.72, P < 0.001) remained as independent predictors of shorter OS. Both the KRAS mutation (HR = 1.30, P = 0.07) and KRAS G12C mutation (HR = 1.47, P = 0.07) reached borderline significance. CONCLUSIONS: In the largest sample used thus for, our study found that approximately 10% of Chinese NSCLC patients had KRAS mutations. Of these, nearly 30% harbored the KRAS G12C mutation subtype, which was most common in male smokers. The KRAS G12C mutation is a biomarker of poor prognosis in Chinese NSCLC patients, which could potentially be improved by G12C-specific inhibitors in the future.(296 words).

Concomitant genetic alterations having greater impact on the clinical benefit of EGFR-TKIs in EGFR-mutant advanced NSCLC than BIM deletion polymorphism.

BACKGROUND: In previous studies, the predictive role of BIM deletion polymorphism with respect to responses to epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) has been controversial. The potential reasons for these inconsistent findings were unknown. METHODS: Data from CTONG0901 clinical trial and medical records of Guangdong Lung Cancer Institute (GLCI) were retrospectively pooled. A total of 194 and 141 EGFR-mutant non-small cell lung cancer (NSCLC) patients treated with first- and second-generation EGFR-TKIs were examined in the CTONG0901 and GLCI cohorts, respectively. Sixty-eight patients were treated with third-generation EGFR-TKIs in the GLCI cohort. The BIM gene status was examined by next-generation sequencing. RESULTS: The frequency of BIM deletion polymorphism was 11.3% and 17.0% in CTONG0901 and GLCI cohorts, respectively. For first- and second-generation EGFR-TKIs in CTONG0901 cohort, objective response (ORR) was 54.5% in BIM deletion group versus 56.4% in wild-type BIM group (P = .87); disease control rate (DCR) was 90.9% versus 88.4% (P = 1.00); progression-free survival (PFS) was 10.5 versus 11.2 months (P = .59); and overall survival (OS) was 20.5 versus 20.5 months (P = .73). In GLCI cohort, ORR was 54.2% versus 60.7% (P = .55); DCR was 91.7% versus 96.6% (P = .27); PFS was 10.1 versus 11.6 months (P = .63); and OS was 58.5 versus 45.0 months (P = .93). For third-generation EGFR-TKIs, ORR was 18.2% versus 63.2% (P = .02); DCR was 81.8% versus 96.5%, (P = .12); PFS was 5.8 versus 9.0 months (P = .13); and OS was 30.0 versus 24.8 months (P = .85). Cox regression analysis showed that concomitant genetic alterations could adversely affect the response to EGFR-TKIs, but not BIM deletion. CONCLUSIONS: The presence of BIM deletion showed no relation to an impaired response to first-, second-, and third-generation EGFR-TKIs in NSCLC patients. The factors influencing the response of EGFR-TKIs were concomitant genetic alterations, but not BIM deletion.

Analysis of resistance mechanisms to abivertinib, a third-generation EGFR tyrosine kinase inhibitor, in patients with EGFR T790M-positive non-small cell lung cancer from a phase I trial.

BACKGROUND: Resistance to third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) presents a major clinical challenge in advanced non-small cell lung cancer (NSCLC). Here, we report resistance mechanisms to abivertinib, a novel third-generation EGFR TKI, from a phase I dose-escalation/expansion study (NCT02330367). METHODS: Patients with EGFR T790M-positive advanced NSCLC and progression on prior EGFR TKIs received abivertinib in dose escalation (50-350 mg twice daily [BID]) or expansion (300 mg BID) cohorts. Patients enrolled at Guangdong Lung Cancer Institute who underwent next-generation sequencing (NGS)-based genomic profiling upon abivertinib progression (prior to October 30, 2018) were enrolled in this exploratory analysis. FINDINGS: Thirty of 73 patients enrolled were eligible for resistance analysis. Upon abivertinib progression, 27 patients provided plasma samples (six patients also provided paired samples from the progression sites) and three patients only provided tissue samples from the progression sites for NGS. A heterogeneous landscape of resistance to abivertinib was observed: 15% (4/27) experienced EGFR T790M loss and 13% (4/30) developing EGFR tertiary mutations including C797S. EGFR amplification was observed in 11 patients (37%), and considered a putative resistance mechanism in seven (23%) patients. Other EGFR-independent resistance mechanisms involved CDKN2A, MET, PIK3CA, HER2, TP53, Rb1 and small-cell lung cancer transformation. INTERPRETATION: Our findings reveal a heterogenous pattern of resistance mechanisms to abivertinib which is distinct from that previously reported with osimertinib. EGFR amplification was the most common resistance mechanism in this cohort. FUND: The National Key R&D Program of China (Grant No. 2016YFC1303800), Key Lab System Project of Guangdong Science and Technology Department - Guangdong Provincial Key Lab of Translational Medicine in Lung Cancer (Grant No. 2012A061400006/2017B030314120).

The in cis compound EGFR mutations in Chinese advanced non-small cell lung cancer patients.

Literatures regarding the prevalence and clinical significance of compound EGFR mutations are limited. Until now, none of retrospective or prospective research has focused on in cis compound EGFR mutations except case reports. In this study, we screened a cohort of 3,000 treatment-naïve Chinese advanced NSCLC patients using capture-based ultra-deep targeted sequencing to evaluate the prevalence of EGFR in cis compound mutations and the efficacy of EGFR-TKI in this population. Of the 3,000 patients screened, 1,266 (42.2%) had EGFR mutation; among them, 15 patients (1.2%) harboring in cis compound EGFR mutations, with 10 patients carrying EGFR L858R in combination with a rare mutation and five patients carrying two rare EGFR mutations. No patient with EGFR 19del was observed. Interestingly, no in trans configuration was identified in this cohort. All of the patients harboring in cis compound EGFR mutations were non-smokers, histologically diagnosed with adenocarcinoma and received first-generation EGFR-TKI. Furthermore, our data also revealed that patients with in cis compound EGFR mutations exhibit comparable PFS to first generation EGFR-TKI comparing to patients with single activating EGFR mutation. This observation was further supported by in silico molecular modeling analyses which demonstrated in cis compound mutations do not alter the ATP-binding pocket of EGFR, thus having no effect on the interaction between gefitinib and EGFR.

Clinical Utility of Cerebrospinal Fluid Cell-Free DNA as Liquid Biopsy for Leptomeningeal Metastases in ALK-Rearranged NSCLC.

INTRODUCTION: Leptomeningeal metastases (LMs) indicated a poor prognosis in NSCLC. LMs were more frequent in driver gene-mutated patients, and cerebrospinal fluid (CSF) cell-free DNA has shown unique genetic profiles of LM in EGFR-mutated LM. However, studies in patients with ALK receptor tyrosine kinase gene (ALK)-rearranged NSCLC with LMs are scarce. METHODS: Patients with lung cancer with ALK rearrangement were screened from September 2011 to February 2018 at our institute. CSF and paired plasma were tested by next-generation sequencing. RESULTS: LMs were diagnosed in 30 (10.3%) of 291 patients with ALK-rearranged lung cancer. A total of 11 paired CSF and plasma samples tested by next-generation sequencing were analyzed. Driver genes were detected in 81.8% of the CSF samples (9 of 11) and 45.5% of the plasma samples (5 of 11) (p = 0.183). The maximum allelic fractions were all higher in CSF than in plasma (p = 0.009). ALK and tumor protein p53 gene (TP53) were the two most frequently mutated genes in CSF. Gatekeeper gene ALK G1202R and C1156F mutations were identified in CSF after resistance to alectinib. Multiple copy number variants were mainly found in CSF, including in EGFR, cyclin D1 gene (CCND1), fibroblast growth factor 3 gene (FGF3), and fibroblast growth factor 4 gene (FGF4). Also found were v-myc avian myelocytomatosis viral oncogene homolog gene (MYC) copy number gains and TP53 and cyclin dependent kinase inhibitor 2A gene (CDKN2A) copy number deletions. Brigatinib seemed to be effective in controlling LM. One case showed that CSF could be used to monitor disease development of LM and longitudinally monitor tumor response. CONCLUSION: Liquid biopsy of CSF is more sensitive than liquid biopsy of plasma to detect targetable alterations, characterizing resistance mechanisms on progression and monitoring tumor response in patients with ALK-rearranged NSCLC with LM. Thus, CSF might be promising as a medium of liquid biopsy in LM.

Mutational landscape and clonal diversity of pulmonary adenoid cystic carcinoma.

Pulmonary adenoid cystic carcinoma is a rare and indolent lung malignancy, characterized by a protracted but unpredictable growth behavior. Currently, the treatment of PACC relies on surgery and local radiotherapy. However, treatment options for advanced PACC patients are limited. A larger number of studies demonstrated that advanced PACC patients obtained limited benefit from chemotherapy. Moreover, only a few case reports revealed PACC patients were candidates for target therapy. Therefore, there is an urgent need to develop novel therapies. Due to its rareness, its mutational landscape remains largely elusive. In this study, we performed capture-based ultra-deep sequencing on multiregional surgical specimens obtained from 8 PACC patients using a panel consisting of 295 cancer-related genes. Our data revealed distinctive mutational spectrum of PACC, which differed from non-small cell lung cancer and adenoid cystic carcinomas originated from other anatomical sites. PACC, lacking mutations in a majority of non-small cell lung cancer driver genes, has frequent mutations in genes participating in chromatin remodeling and NOTCH signaling pathway. We also elucidated spatial intra-tumoral heterogeneity, which varied among cases. Most mutations in chromatin remodelers were subclonal. Collectively, our findings elucidated molecular signature associated with PACC and highlighted the potential for epigenetic therapy in this disease.

Lung Adenocarcinoma Harboring EGFR T790M and In Trans C797S Responds to Combination Therapy of First- and Third-Generation EGFR TKIs and Shifts Allelic Configuration at Resistance.

INTRODUCTION: The efficacy of osimertinib was compromised by the development of resistance mechanisms, such as EGFR C797S. In vitro study proved that cells harboring EGFR C797S in trans with T790M are sensitive to a combination of first- and third-generation EGFR tyrosine kinase inhibitors. However, this has not been reported clinically. METHODS: We performed capture-based sequencing on longitudinal plasma samples obtained at various treatment milestones from a patient with advanced lung adenocarcinoma who was undergoing targeted therapy. RESULTS: At the development of resistance to osimertinib, the patient's plasma sample revealed EGFR C797S located in trans with T790M. He achieved partial response accompanied by undetectable C797S after commencement of a combinatorial treatment consisting of erlotinib and osimertinib. After 3 months of progression-free survival, he experienced progressive disease with emergence of EGFR C797S located in cis to T790M. CONCLUSION: We report the first clinical evidence of efficacy generated by combination therapy consisting of first- and third-generation EGFR tyrosine kinase inhibitors targeting concomitant EGFR T790M and C797S in trans. We also reveal that the clonal progression of C797S from in trans to in cis at disease progression may serve as a potential resistance mechanism.

RAD18 polymorphisms are associated with platinum-based chemotherapy toxicity in Chinese patients with non-small cell lung cancer.

AIM: Although targeted therapy is very efficient for lung cancer, traditional platinum-based chemotherapies are still the principal strategy in the absence of positive biomarkers. The aim of the present study is to evaluate the contribution of RAD18 polymorphisms to platinum-chemotherapy response and its potential side effects in Chinese patients with non-small cell lung cancer (NSCLC). METHODS: A total of 1021 Chinese patients with histological diagnosis of advanced NSCLC were enrolled. Treatment responses were classified into 4 categories (complete response, partial response, stable disease and progressive disease). Gastrointestinal and hematological toxicity incidences were assessed twice a week during the first-line treatment. Ten RAD18 SNPs were genotyped. A logistic regression model was utilized to analyze the associations between RAD18 SNPs and treatment response or toxicity. RESULTS: Among the 10 SNPs tested, none was significantly correlated with the treatment response in a combined cohort. For gastrointestinal toxicity incidences, rs586014 was significantly associated with an increased risk of grade 3 or 4 gastrointestinal toxicity in non-smokers and in the combined cohort; rs654448 and rs618784 were significantly associated with gastrointestinal toxicity in non-smokers; rs6763823 was significantly associated with gastrointestinal toxicity in smokers. For hematological toxicity incidences, rs586014, rs654448 and rs618784 were significantly associated with hematologic toxicity in non-smokers; rs6763823 and rs9880051 were significantly associated with leukocytopenia in smokers. CONCLUSION: RAD18 polymorphisms are correlated with the side effects of platinum-chemotherapy in Chinese patients with advanced NSCLC.