19del Mutation Research Articles

EP16.03-038 Single-cell Analyses Reveal Tumor Microenvironment Differences between EGFR 19del and L858R mutations in Lung Adenocarcinoma

Lung cancer is the leading cause of cancer-related mortality among malignant tumors worldwide. Lung adenocarcinoma (LUAD) accounts for 40% of all cases and is the most common histological subtype of non-small cell lung cancer (NSCLC). Activating somatic mutations, mostly identified as 19del and L858R in EGFR tyrosine kinase domain, may predict response to EGFR tyrosine kinase inhibitors (TKIs) in NSCLC patients. Although EGFR 19del and L858R patients are sensitive to TKIs, they showed different clinical benefits such as prolonged PFS in 19del patients.

Using combined CT-clinical radiomics models to identify epidermal growth factor receptor mutation subtypes in lung adenocarcinoma.

To investigate the value of computed tomography (CT)-based radiomics signatures in combination with clinical and CT morphological features to identify epidermal growth factor receptor (EGFR)-mutation subtypes in lung adenocarcinoma (LADC). From February 2012 to October 2019, 608 patients were confirmed with LADC and underwent chest CT scans. Among them, 307 (50.5%) patients had a positive EGFR-mutation and 301 (49.5%) had a negative EGFR-mutation. Of the EGFR-mutant patients, 114 (37.1%) had a 19del -mutation, 155 (50.5%) had a L858R-mutation, and 38 (12.4%) had other rare mutations. Three combined models were generated by incorporating radiomics signatures, clinical, and CT morphological features to predict EGFR-mutation status. Patients were randomly split into training and testing cohorts, 80% and 20%, respectively. Model 1 was used to predict positive and negative EGFR-mutation, model 2 was used to predict 19del and non-19del mutations, and model 3 was used to predict L858R and non-L858R mutations. The receiver operating characteristic curve and the area under the curve (AUC) were used to evaluate their performance. For the three models, model 1 had AUC values of 0.969 and 0.886 in the training and validation cohorts, respectively. Model 2 had AUC values of 0.999 and 0.847 in the training and validation cohorts, respectively. Model 3 had AUC values of 0.984 and 0.806 in the training and validation cohorts, respectively. Combined models that incorporate radiomics signature, clinical, and CT morphological features may serve as an auxiliary tool to predict EGFR-mutation subtypes and contribute to individualized treatment for patients with LADC.

Sequential Afatinib and Osimertinib in Asian Patients with EGFR Mutation-Positive Non-Small Cell Lung Cancer and Acquired T790M: Combined Analysis of Two Global Non-Interventional Studies.

ObjectiveTwo recent non-interventional trials, GioTag and UpSwinG, demonstrated encouraging time-to-treatment failure (TTF) and overall survival (OS) in patients with epidermal growth factor receptor (EGFR) mutation-positive non-small cell lung cancer (NSCLC) (Del19 or L858R) who received sequential afatinib/osimertinib, especially in Asians. Here, we have undertaken a combined analysis of Asian patients from both studies.Materials and MethodsExisting medical/electronic records were identified for consecutive EGFR-tyrosine kinase inhibitor (TKI)-naïve patients who received first-line afatinib/second-line osimertinib in “real-world” practice (all T790M-positive). Patients with active brain metastases were excluded. The primary objective was TTF. OS was a key secondary objective.ResultsOne hundred and sixty-eight patients were analyzed. Most patients were recruited from South Korea or Japan (52/21%). At the start of afatinib, median age (range) was 61.5 years (35–88), 58% were female, Eastern Cooperative Oncology Group Performance Status (ECOG PS) (0/1/≥2) was 29/62/9%, 17% had brain metastases, and EGFR mutation status (Del19/L858R) was 65/35%. At the start of osimertinib, ECOG PS (0/1/≥2) was 22/61/17% and 14% had brain metastases. Median TTF and OS were 30.0 months (95% CI: 24.5–32.5) and 45.2 months (95% CI: 41.7–71.1), respectively. Median OS was 63.5 months in patients with a Del19 mutation. Median OS in patients with brain metastases or ECOG PS ≥2 was 26.4 and 33.1 months, respectively.ConclusionSequential afatinib/osimertinib showed encouraging activity in Asian patients with EGFR mutation-positive NSCLC and T790M-mediated acquired resistance, especially those with Del19-positive disease. Activity was observed across “real-world” patients including those with poor ECOG PS and/or brain metastases. ECOG PS and incidence of brain metastases remained stable prior to, and after, afatinib.

Primary lesion radiotherapy during first-line icotinib treatment in EGFR-mutated NSCLC patients with multiple metastases and no brain metastases: a single-center retrospective study

The most frequent mode of progression in the majority of non-small cell lung cancer (NSCLC) patients treated with Epidermal growth factor- receptor tyrosine kinase inhibitors (EGFR-TKIs) is failure to respond to treatment at the primary lesion, suggesting that concurrent radiotherapy (CRT) to the primary lesion (CPRT) during first-line treatment with EGFR-TKI may be anovel therapeutic approach with apotential of additional benefit for metastatic NSCLC. Therefore, this study investigated the progression-free survival (PFS) and safety of CPRT during first-line icotinib treatment in NSCLC patients with EGFR mutations. EGFR-mutant NSCLC patients diagnosed with limited multiple metastases were treated with first-line icotinib. The decision to treat the primary lesions with radiation largely depended on the patient's preference. The study endpoints included PFS, toxicity, progression pattern, and acquisition of the T790M mutation. The median PFS in the CPRT and Non-CPRT groups was 13.6 and 10.6months (hazard ratio [HR] 0.23, 95% confidence interval [CI] 0.15-0.37, P < 0.001). Subgroup analysis showed that the results were statistically significant with 14.7 and 11.5months for the 19del mutation (HR 0.20, 95% CI 0.10-0.40, P < 0.001) and 12.9 and 9.9months for the L858R mutation (HR 0.25, 95% CI 0.13-0.48, P < 0.001). There were no reports of interstitial pneumonia associated with treatment at grade4 or above. Patients who received CPRT during first-line icotinib treatment had the potential to decrease the primary lesion progression (P < 0.05) without increasing newly metastatic lesions (P > 0.05). The proportion of acquired T790M mutations was 26.7% and 45.7% in both groups (P > 0.05). This study suggests that CPRT is aviable option for patients with EGFR-sensitive mutations in NSCLC with limited multiple metastases during first-line icotinib treatment, which can significantly improve PFS with acceptable toxicities. Data on progression patterns and T790M mutations suggest the need to further investigate the benefits of radiation treatment from amolecular perspective.

EGFR mutation types and abundance were associated with the overall survival of advanced lung adenocarcinoma patients receiving first-line tyrosine kinase inhibitors.

BackgroundEpidermal growth factor receptor tyrosine kinases inhibitors (EGFR-TKIs) are currently recognized as the standard treatment for advanced non-small cell lung cancer (NSCLC) patients with EGFR mutations. Clinically found patients with different EGFR mutational status have different prognosis.MethodsA retrospective cohort study was performed to explore the relationship between EGFR mutations and abundance with patient survival by using patient data from the Affiliated Cancer Hospital of Zhengzhou University between January 2013 and November 2016. All patients involved in the present study had sensitive EGFR mutations [either exon 19 deletion (DEL) or exon 21 L858R] and treated by EGFR-TKIs. They were followed up every three months until lost or dead. Mutation abundance was calculated as the copies of EGFR mutation divided by copies of EGFR locus, and the cut-off values for 19DEL and L858R were 4.9% and 9.5%, respectively.ResultsTotal of 236 patients were included, comprising 116 (49.2%) patients with 19DEL mutation and 120 (50.8%) patients with L858R mutation. The median follow-up duration was 23.2 months (95% CI: 14.9–26.7 months). Overall survival (OS) was significantly longer in patients with 19DEL mutation (20.9 months, 95% CI: 17.7–24.1 months versus 17.0 months, 95% CI: 14.4–19.6 months in patients with L858R; P=0.008) and in patients with high mutation abundance (20.9 months, 95% CI: 18.3–23.5 months versus 13.0 months, 95% CI: 10.3–15.7 months in patients with low mutation abundance; P<0.001). Multivariate Cox regression including age, performance status and tumor stage revealed that longer OS was independently associated with 19DEL mutation (HR: 0.48, 95% CI: 0.39–0.67, P=0.033) and high mutation abundance (HR: 0.62, 95% CI: 0.50–0.79, P=0.027).ConclusionsEGFR mutation types and abundance was associated with the patients’ survival which might be used to predict the efficacy of targeted therapy by EGFR-TKIs.

The landscape of NRG1 fusions based on NGS in Chinese solid tumor patients.

e15073 Background: Neuregulin 1 gene ( NRG1) fusions are oncogenic in various tumor types and represent an emerging potential therapeutic target. In the previous reports, NRG1 fusions are overall rare (0.12%) in the Western population, being seen most frequently in NSCLCs. The incidence of NRG1 fusions in a variety of solid tumors based on NGS has been explored limitedly in Chinese patients. Methods: FFPE samples and matched peripheral blood were collected for NGS based 450 cancer genes panel assay and RNA panel assay.Somatic variants were analyzed following CAP/CLIA-certificated workflows, including Single Nucleotide Variant (SNV), Copy Number Variation (CNV), large insertion and deletions (Lindel) and gene rearrangements. Results: A total of 47 patients harboring NRG1 fusions and four of them were detected in RNA level. Non-small cell lung cancer (NSCLC) was the most common cancer type with the incidence of 0.19% (25/13089). The followed cancer types were bone sarcoma, breast carcinoma, pancreatic adenocarcinoma and colorectal carcinoma with the frequency of 0.30% (3/973), 0.16% (3/1850), 0.14% (3/2098) and 0.07% (3/4344) respectively. CD74 (10.1%), SLC34A2 (10.1%) and WRN (4.3%) represented the most common NRG1 fusion partners, other known partners contained CDH1, HMBOX1, ADAM5 and UNC5D. In total, 76.6% of the partners were novel partners, and the most common break points of NRG1 were intron5 and intron1. The 47 NRG1 fusion patients evenly distributed in female (49%) and male (51%), and 44.7% were at advanced stage (stage ≥ III). The median age was 57 years old (range, 8-86 years old) and the median TMB was 3.3 muts/Mb (range, 0-30.5). TP53 (48.9%), CDKN2A (14.9%) and ERBB2/FGFR1/MUC16/SMAD4 (12.8%) were the most common co-occurred mutated gene. In the alterations of ERBB2, 50% were amplifications and 2 patients were breast carcinoma. Only one patient showed ALK fusion and one showed FGFR1 fusion. Among all patients, 8.5% included p.G12X mutation of KRAS and 10.6% included alterations of EGFR with two L858R and two 19del mutations. Conclusions: This study revealed NRG1 fusions in approximately 0.19% of Chinese NSCLC tumor pts and presented the frequency of same common tumors. Also the genomic and clinical feature were analysed. NGS panel sequencing and OrigiFus algorithm showed the advantage of detecting NRG1 fusion and providing structure information of partners which could potentially guide more precise treatment options.

Efficacy of osimertinib in patients with EGFR mutant lung cancer harboring the uncommon exon 19 deletion, L747_A750&gt;P.

e21112 Background: EGFR exon 19 deletions (del19) are largely considered to have uniform sensitivity to EGFR tyrosine kinase inhibitors (TKIs). Approximately 70% of del19 tumors harbor the most common deletion, E756_A750del; however, many “uncommon” variants comprise the remainder of this group. In preclinical studies, the uncommon del19, L747_A750 &gt; P, demonstrates diminished sensitivity to the third generation TKI, osimertinib [. Identifying differences in clinical outcomes with osimertinib treatment could have therapeutic implications for patients (pts) with EGFR del19 non-small cell lung cancer (NSCLC). Methods: We conducted a multi-center retrospective cohort study of pts with metastatic EGFR del19 NSCLC treated with osimertinib. We compared progression free survival (PFS, time from TKI initiation to clinically significant growth of existing lesions or new lesions on imaging or death) and overall survival (OS) of pts with tumors harboring E746_A750del and L747_A750 &gt; P who received osimertinib in the first line (1L) or in second or later lines of therapy and were T790M+ (≥2L). The Kaplan Meier method and Cox model were used to estimate PFS and OS, and multivariable logistic regression was used to estimate the odds of achieving PFS &gt; 12 months. Multivariable analyses adjusted for baseline covariates- age, sex, race, and smoking. Results: From March 2013 to December 2021, 86 pts with EGFR E746_A750del and 36 with L747_A750 &gt; P were treated with osimertinib. For 1L osimertinib, E746_A750del was associated with significantly prolonged PFS vs. L747_A750 &gt; P (median 21.3 months (95% CI 17.0-31.7) vs. 11.7 months (10.8-29.4)) in the adjusted analysis (hazard ratio [HR] 0.52 [95% CI, 0.28-0.98, p = 0.043]). Pts with the common del19 mutation were more likely to achieve PFS &gt; 12 months with 1L osimertinib than those with the L747_A750 &gt; P mutation (Odds Ratio 4.14 (1.41-12.15), p 0.0097). OS exhibited a similar trend with a median OS that that was not reached (NR) at 40 months of follow-up among those with E746_A750del vs 26 months for L747_A750 &gt; P (adjusted HR 0.52 [95% CI, 0.23-1.19], p = 0.120). For pts treated with ≥2L osimertinib, there was also a trend towards favorable PFS and OS for pts with tumors harboring E746_A750del. Conclusions: The del19 mutation L747_A750 &gt; P is associated with inferior PFS compared to the common E746_A750del mutation in pts treated with 1L osimertinib. Understanding differences in osimertinib efficacy among EGFR del19 subtypes could alter management of these pts in the future.[Table: see text]

Real-world analysis of the EGFR mutation detection in plasma ctDNA from patients with non-small cell lung cancer.

e21069 Background: Plasma sample has emerged as a promising surrogate sample for EGFR mutation detection in advanced non-small cell lung cancer (NSCLC). In clinical practice, whether EGFR variants in pretreatment plasma ctDNA of advanced lung cancer can predict prognosis in addition to guiding targeted therapy remains to be further explored. Methods: In this study, we retrospectively enrolled 315 NSCLC patients from Beijing Chest Hospital, 94.9% of whom were in stage IIIB-IV. EGFR gene mutation data from tissue detected by ARMS-PCR (Amoy Diagnostics, Xiamen, China) and paired plasma samples within one month of admission detected by SuperARMS-PCR (Amoy Diagnostics, Xiamen, China) were collected. The patients’ clinicopathological characteristics and treatment information were also collected for further analysis. Differences in PFS of targeted therapy between patients with positive and negative pretreatment plasma ctDNA EGFR mutation were compared. Results: EGFR-positive rate of tissue and plasma ctDNA was 65.1% (205/315) and 43.8% (138/315), respectively. L858R, 19-DEL, T790M, G719X, 20-INS, and L861Q mutations were detected in both samples. The sensitivity, specificity, PPV, NPV and concordance of ctDNA detection was 65.4%,96.4%, 97.1%, 59.9%, and 76.2%, respectively. In the study, patients’ pathological subtype was the factor affected plasma ctDNA EGFR alteration detection accuracy. The concordance in adenocarcinoma patients was obviously higher than that in non-adenocarcinoma (p = 0.02). 92 treatment naïve advanced patients with tissue EGFR mutation were received first and second-generation EGFR tyrosine kinase inhibitors (TKIs) therapies. 59.8% (55/92) patients also had EGFR mutation in plasma ctDNA, 40.2% (37/92) patients had no detectable EGFR mutations in plasma ctDNA. The median PFS in plasma ctDNA EGFR positive patients was 7.0 months versus 14.0 month in plasma ctDNA EGFR negative patients, with significantly difference (p = 0.004). Conclusions: Plasma sample could be a surrogate sample for molecular test when tissue sample was unavailable. The poor prognosis was observed in treatment naïve advanced NSCLC patients with baseline plasma EGFR mutation.

Correlation between PD-L1 high-expression and EGFR variants in non-small cell lung cancer.

e21062 Background: In previous studies, researchers have demonstrated that activation of the epidermal growth factor receptor (EGFR)-mutant pathway induced PD-L1 expression. In this study, we explored the correlation between PD-L1 expressions and EGFR variations. Methods: This study enrolled 2417 non-small cell lung cancer(NSCLC) patients harboring diverse EGFR mutations, including exon 19 deletions(19del)(n = 1045), L858R(n = 906), G719X(n = 176), S768I(n = 62), L861Q(n = 89) and exon 20 insertions(20ins)(n = 139). The stages range from I through IV, the majority were female(n = 1452, 60.07%) and adenocarcinoma(n = 1788, 73.98%), median age was 62(range 24-92). In this study, we retrospectively analyzed variants using next-generation sequencing(NGS). PD-L1 status was determined by VENTANA PD-L1 (SP263) Assay, TPS≥50% and TPS＜1% was the cut-off value for PD-L1 high-expression and negative separately. The 95% confidence interval (CI) was used to estimate the precision of the odds ratio (OR). Results: 1) Even though we observed subtle differences of PD-L1 high-expression ratio among various subtypes(19del：9.57%, L858R: 9.27%, G719X: 12.50%, S768I: 11.29%, L861Q: 7.87%, exon 20ins: 12.23%) in total patients, that PD-L1 high-expression was more likely to shown with G719X/S768I/exon 20ins than with 19del/L858R/L861Q, there was no statistically significant between 19del and other mutation：L858R(p = 0.8224), G719X (p = 0.2319), S768I(p = 0.6563), L861Q(p = 0.5982), exon 20ins(P = 0.3247). 2)We analyzed 742 treatment-naive EGFR-mutant NSCLC patients (PD-L1 negative, n = 624; high-expression, n = 118), PD-L1 high-expression group come with higher frequency of EGFR copy number variation(CNV)(OR = 2.2364, 95%CI, 1.4576-3.4312, p = 0.0002). Importantly, the ratio of high-level EGFR CNV(CN≥6) was higher in PD-L1 high-expression group than that in the negative group(OR = 3.0668, 95% CI, 1.3745-6.8427, p = 0.0062). Conclusions: In the newly diagnosed EGFR-mutant NSCLC patients, PD-L1 high-expression patients come with more frequent high-level EGFR CNV. There is no statistical significance between PD-L1 high-expression and EGFR mutation subtypes. As for how the EGFR signal affects PD-L1 expression, the mechanism needs to be further explored. The association between driver genes and immune checkpoints is a definite interest of future investigations.

Development of a Nomogram Based on 3D CT Radiomics Signature to Predict the Mutation Status of EGFR Molecular Subtypes in Lung Adenocarcinoma: A Multicenter Study.

BackgroundThis study aimed to noninvasively predict the mutation status of epidermal growth factor receptor (EGFR) molecular subtype in lung adenocarcinoma based on CT radiomics features.MethodsIn total, 728 patients with lung adenocarcinoma were included, and divided into three groups according to EGFR mutation subtypes. 1727 radiomics features were extracted from the three-dimensional images of each patient. Wilcoxon test, least absolute shrinkage and selection operator regression, and multiple logistic regression were used for feature selection. ROC curve was used to evaluate the predictive performance of the model. Nomogram was constructed by combining radiomics features and clinical risk factors. Calibration curve was used to evaluate the goodness of fit of the model. Decision curve analysis was used to evaluate the clinical applicability of the model.ResultsThere were three, two, and one clinical factor and fourteen, thirteen, and four radiomics features, respectively, which were significantly related to each EGFR molecular subtype. Compared with the clinical and radiomics models, the combined model had the highest predictive performance in predicting EGFR molecular subtypes [Del-19 mutation vs. wild-type, AUC=0.838 (95% CI, 0.799-0.877); L858R mutation vs. wild-type, AUC=0.855 (95% CI, 0.817-0.894); and Del-19 mutation vs. L858R mutation, AUC=0.906 (95% CI, 0.869-0.943), respectively], and it has a stable performance in the validation set [AUC was 0.813 (95% CI, 0.740-0.886), 0.852 (95% CI, 0.790-0.913), and 0.875 (95% CI, 0.781-0.929), respectively].ConclusionOur combined model showed good performance in predicting EGFR molecular subtypes in patients with lung adenocarcinoma. This model can be applied to patients with lung adenocarcinoma.

67P Distinct concomitant genetic alterations in EGFR-mutant non-small cell lung cancer patients with brain metastases

EGFR-mutant NSCLC with brain metastases displays diverse trajectories to tyrosine kinase inhibitor (TKI) treatment. Exploring concomitant genetic alterations might describe the underlying mechanisms and identify different subsets of patients. From Jan 2013 to Dec 2020, NSCLC patients with brain metastases were screened and patients harboring EGFR mutation enrolled. Clinical data of patients with next-generation sequencing (NGS) data were then analyzed. Kaplan-Meier method and the Cox proportional hazards model were used for survival analysis. Based on the multivariable analysis, a nomogram was constructed using R version 4.0.5. A total of 2657 NSCLC patients with brain metastases were screened and 737 harboring EGFR mutation, among 73 patients with NGS data, all receiving EGFR TKI treatment, the median age was 58.1years, 35(47.9%) were male, 35(47.9%) were EGFR 19Del. Median overall survival (OS) were 23.6 months. Fifty-five patients (75.3%) harbored concomitant alterations, with TP53 (45.2%), EGFR amplification (12.3%) and RB1(9.6%) being the top three most frequently alterations. Concomitant genetic alterations were significantly associated with reduced OS(23.2 months vs NR, P=0.016). Especially, TP53 mutation (HR=1.8, 95%CI:1.0-3.2) and EGFR amplification (HR=2.5, 95%CI:1.2-5.6) were associated with significantly worse OS. Among the patients with driver genes(HR= 8.0, 95%CI:2.0-31.1) or tumor suppressor genes(HR= 10.6, 95%CI:1.8-60.2) had significantly worse OS than patients without concomitant alterations. However, OS was comparable for patients with local surgical or radiotherapy. As shown in the nomogram, a higher total score was associated with having EGFR 19del mutations and without concomitant alterations indicated a higher likelihood of longer OS. This study reveals the widespread existence of concomitant alterations in patients with EGFR-mutant NSCLC with brain metastases. Concomitant alterations were associated with the poorer clinical outcomes of patients. Based on the nomogram, we identified that the subset of patients without concomitant alterations and EGFR 19Del could derive more survival benefit from the EGFR-TKI treatment.

Clinical Characteristics and Prognosis of 76 Lung Adenocarcinoma Patients Harboring EGFR Mutations with Pleural Effusion at Initial Diagnosis: A Single-center Retrospective Study

背景与目的恶性胸腔积液是肺腺癌患者常见临床表现之一，肺腺癌初诊时合并胸腔积液提示预后不佳。表皮生长因子受体(epidermal growth factor receptor, EGFR)突变主要发生在肺腺癌患者中，不同亚型预后不同。初诊时不同亚型EGFR突变阳性合并胸腔积液肺腺癌患者的临床特征及预后因素目前尚不明确，本研究拟探讨此类患者的临床特征及预后影响因素，旨在为此类患者提供诊治参考。方法回顾性分析2012年1月-2021年6月期间，北京大学第三医院肿瘤化疗与放射病科收治的初诊时EGFR突变阳性且合并胸腔积液肺腺癌患者的临床特征、治疗方法、治疗疗效和一线治疗中位无进展生存期(progression-free survival, PFS)，采用Pearson卡方检验或Fisher精确概率法进行组间比较，采用Kaplan-Meier法进行生存分析，采用Cox比例风险回归模型进行多因素分析。结果共筛选出符合入组条件的患者76例，EGFR经典突变19del、21L858R和非经典突变的发生率分别为46.0%、38.2%和15.8%，3种突变亚型在性别、年龄、发病时有无呼吸困难、是否合并其他远处转移、胸腔积液部位、胸腔积液量、有无合并其他部位积液、肿瘤原发灶-淋巴结-转移(tumor-node-metastasis, TNM)分期、有无合并其他基因突变、胸腔积液的治疗方法等方面无显著差异(P > 0.05)。在EGFR经典突变19del、21L858R和非经典突变患者中，一线应用化疗的占比分别为17.1%、20.7%和58.3%(P=0.001)；一线疾病控制率分别为94.3%、75.9%和50.0%(P=0.003)；胸腔积液控制率分别为94.3%、79.3%和66.7%(P=0.04)；PFS分别为287 d、327 d和55 d(P=0.001)。单因素分析显示EGFR突变亚型、胸腔积液控制情况、一线治疗药物、一线治疗疗效与PFS显著相关(P < 0.05)，Cox多因素分析显示仅EGFR突变类型、一线治疗疗效是PFS的独立预后因素(P < 0.05)。结论初诊EGFR突变阳性且合并胸腔积液的肺腺癌患者中，EGFR经典突变(19del和21L858R)患者的PFS显著优于非经典突变者，提升一线治疗疗效是改善此类患者预后的关键。

First-line therapeutic strategy for patients with advanced non-small cell lung cancer with Leu858Arg epidermal growth factor receptor mutations: a Bayesian network meta-analysis.

Aim:The objective of this network meta-analysis was to determine the most useful first-line therapeutic strategy for patients with advanced (IIIB/IV or relapsed) non–small cell lung cancer (NSCLC) with epidermal growth factor receptor (EGFR) Leu858Arg or EGFR 19del mutations.Methods:PubMed, the Web of Science, Medline, and reports of the top three world cancer conferences (WCLC, ESMO, and ASCO) were searched for appropriated randomized controlled studies (RCTs) discussing the use of various generations of tyrosine kinase inhibitors (TKIs; gefitinib, erlotinib, icotinib, afatinib, dacomitinib, osimertinib, aumolertinib), chemotherapy [pemetrexed-based chemotherapy (PC), non-pemetrexed-based chemotherapy (NPC)], and different combined therapies (osimertinib plus bevacizumab, afatinib plus cetuximab, erlotinib plus bevacizumab, erlotinib plus ramucirumab, gefitinib plus apatinib, gefitinib plus PC, and gefitinib plus pemetrexed) to treat patients with advanced NSCLC with EGFR Leu858Arg or 19del mutations. OpenBugs and Stata software were used to analyze the data.Results:We included 21 studies with 16 arms (including 2479 cases with EGFR Leu858Arg mutations and 3325 cases with EGFR 19del mutations). Among patients with NSCLC with EGFR Leu858Arg mutations, compared with the first-generation TKIs (such as gefitinib), the second- or third-generation TKIs [dacomitinib: hazard ratio (HR) = 0.63; 95% confidence index (CI) = (0.45, 0.89); osimertinib: HR = 0.63; 95% CI = (0.42, 0.97)] showed significant benefits in improving progression-free survival (PFS), as did afatinib plus cetuximab [HR = 1.98; 95% CI = (1.01, 3.95)], erlotinib plus bevacizumab [HR = 1.79; 95% CI = (1.22, 2.62)], and erlotinib plus ramucirumab [HR = 1.62; 95% CI = (1.07, 2.48)]. In terms of overall survival (OS), these 16 arms showed no significant differences between each other (p > 0.05). Among patients with NSCLC with EGFR 19del mutations, compared with the first- or second-generation TKIs (such as gefitinib and afatinib), aumolertinib [versus gefitinib: HR = 0.39; 95% CI = (0.28, 0.55) versus afatinib: HR = 0.53; 95% CI = (0.35, 0.84)] and osimertinib [versus gefitinib: HR = 0.40; 95% CI = (0.32, 0.51) versus afatinib: HR = 0.53, 95% CI = (0.38, 0.79)] showed significantly beneficial effects. Among these first-line therapeutic strategies for patients with EGFR Leu858Arg mutations, the combination of afatinib and cetuximab ranked as the best to prolong PFS (33.0%). For NSCLC patients with 19del mutations, however, osimertinib plus bevacizumab was the best at prolonging PFS (84.3%).Conclusion:For NSCLC patients with EGFR Leu858Arg mutations, the second-generation TKIs, the third-generation TKIs, and the combined treatments showed better efficacy than the first-generation TKIs for PFS. There were, however, no significant differences between each group for OS.

Three-Dimensional Topological Radiogenomics of Epidermal Growth Factor Receptor Del19 and L858R Mutation Subtypes on Computed Tomography Images of Lung Cancer Patients

Three-Dimensional Topological Radiogenomics of Epidermal Growth Factor Receptor Del19 and L858R Mutation Subtypes on Computed Tomography Images of Lung Cancer Patients

Hypomethylation of DAPL1 associated with prognosis of lung cancer patients with EGFR Del19 mutation

Objective: To investigate the effect of apoptosis-associated protein kinase-like 1 (DAPL1) hypomethylation on prognosis of lung cancer patients with epidermal growth factor receptor gene exon 19 deletion (EGFR Del19) mutation. Methods: The clinicopathological data of lung cancer patients in databases of genomic data sharing (GDC) TCGA lung adenocarcinoma, TCGA lung adenocarcinoma, and TCGA lung cancer were collected to analyze the effect of DAPL1 methylation level on the prognosis of patients with EGFR Del19 mutation. Linear regression model was used for correlation analysis, Kaplan-Meier method was used to draw the survival curve, and the difference of survival curve between the two groups was tested by Log rank. Results: In GDC TCGA lung adenocarcinoma, TCGA lung adenocarcinoma and TCGA lung cancer databases, the 5-year survival rates of lung cancer patients with high DAPL1 expression (31.9%, 27.5% and 33.0%, respectively) were higher than those with low DAPL1 expression (11.0%, 11.6% and 13.8%, respectively). The differences were statistically significant (P=0.006, 0.028 and 0.025, respectively). The median expression levels of DAPL1 in patients with EGFR Del19 mutation (12.8, 2.75 and 2.9, respectively) were higher than those in patients with other EGFR mutations (11.6, 1.75 and 1.8, respectively, P<0.05). In TCGA lung adenocarcinoma and TCGA lung cancer database, the 5-year survival rate of lung cancer patients with lower DAPL1 methylation levels (22.4% and 16.4%, respectively) were higher than those of lung cancer patients with higher DAPL1 methylation levels (15.1% and 14.2%, respectively), with statistical significance (P<0.05). The expression level of DAPL1 was positively correlated with the EGFR mutant subtype (r=0.909, P<0.05), and negatively correlated with DNA methylation (r=-0.891, P<0.05). The expression of DAPL1 in lung cancer patients was regulated by DNA methylation, which affected the prognosis of lung cancer patients. Conclusion: High DAPL1 expression, or hypomethylation, is associated with lung cancer EGFR Del19 mutation subtype, and DAPL1 hypomethylated lung cancer patients have longer overall survival.

Front-Line Therapy in EGFR Exon 19 Deletion and 21 Leu858Arg Mutations in Advanced Non-Small Cell Lung Cancer: A Network Meta-Analysis

Objective This study aimed to compare the efficacy of different first-line strategies based on different EGFR mutation types (19 deletion and 21 Leu858Arg mutations). Methods We conducted a systematic review and network meta-analysis (NMA) by searching and analyzing RCTs on PubMed, Embase, Cochrane Library, ASCO.org, and ESMO.org, from inception to September 30th, 2020. Results Nineteen RCTs involving 5450 patients were finally included in this study, covering 10 different treatment strategies. The Bayesian ranking results suggested that, in terms of PFS, in the overall population and in patients with 19del mutation, osimertinib was most likely to rank the first, with the cumulative probabilities of 41.89% and 45.73%, respectively, while for patients with 21 Leu858Arg mutation, standard of care (SoC, represents first-generation EGFR-TKIs in this NMA) + chemotherapy was most likely to rank the first, with the cumulative probabilities of 30.81% in PFS. Moreover, SoC + chemotherapy provided the best overall survival benefit for the overall population and patients with 19del, with the cumulative probabilities of 57.85% and 33.51%, respectively. In contrast, for patients with 21 Leu858Arg mutation, dacomitinib showed the most favorable overall survival, with the cumulative probabilities of 36.73%. Conclusions In this NMA, osimertinib and SoC combined with chemotherapy would be the optimal first-line treatment options for advanced NSCLC patients harboring EGFR 19 deletion mutation and 21 Leu858Arg mutation, respectively. This finding is likely to be adopted in clinical practice and provide guidance for future clinical study design. Systematic review registration: INPLASY2020100059.

Real-time digital polymerase chain reaction (PCR) as a novel technology improves limit of detection for rare allele assays.

BackgroundTumor heterogeneity may lead to false negative test results for tissue biopsy-based companion diagnostic tests. Real-time polymerase chain reaction (PCR) and digital PCR assays are used to detect rare alleles in cell-free circulating DNA for liquid biopsies; however, those tests lack strong sensitivity at low allele frequencies. We show here a novel real-time digital PCR instrument that utilizes cycle-based amplification curves to further improve the sensitivity and quantification accuracy of digital PCR.MethodsThe novel real-time digital PCR instrument was compared to an endpoint digital PCR system to determine the sensitivity and quantification accuracy of both instruments. Samples were all thermal cycled on the real-time digital PCR instrument but were analyzed on both endpoint and real-time digital PCR instruments to compare the performance without introducing other variables. Contrived samples for epidermal growth factor receptor (EGFR) exon 19 deletion, T790M, and L858R point mutations as well as human epidermal growth factor receptor 2 (HER2) amplification were tested. Different mutant allele frequencies and wildtype to mutant gene copy number ratios were tested for EGFR and HER2, respectively.ResultsBy removing false positive datapoints using real-time amplification curves, real-time digital PCR improved sensitivity by lowering the baseline for wildtype samples. For EGFR 19del assay, samples with 2 or more fluorescein amidite (FAM) labeled positive wells are determined positive by real-time digital PCR, while a minimum of 5 FAM positive datapoints is needed by endpoint digital PCR. Improved limit of detection for EGFR 19del mutation was also observed. Real-time digital PCR also had better quantification accuracy and sensitivity, resulting in the mutant allele frequencies being closer to the expected values for all EGFR mutations, especially at very low allele frequencies. However, at high allele frequencies or for gene amplification assays, real-time digital PCR is comparable with endpoint digital PCR.ConclusionsThis novel technology with improved sensitivity is important and needed because it addresses current issues with liquid biopsy tests. Due to limited amounts of circulating tumor DNA (ctDNA) obtained for liquid biopsy tests, few copies of mutant alleles are expected. With the lower baseline of real-time digital PCR, false negative test results from tissue biopsy would be more effectively reduced, leading to more patients receiving the targeted therapy they need for better survival.

B7-H4 is increased in lung adenocarcinoma harboring EGFR-activating mutations and contributes to immunosuppression.

PD-1/PD-L1 inhibitors have shown clinical benefit in lung adenocarcinoma (LUAD). However, the immunotherapy strategy is less effective in patients with EGFR-activating mutations (EGFR MT). Studies showed that besides low expression of PD-L1, the absence of TILs and distinct expression profile of immune checkpoint molecules might be associated with low response of the patient subset. In this study, we first compared CD8A, GZMB and PRF1 mRNA levels in different LUAD subtypes harboring different driver mutations by dataset analyses and investigated the association between 15 well-defined B7-CD28 family members and driver mutations. The results showed that the decreases in the density and function of CD8+ TILs, CD274 (PD-L1 gene), and CD86 and increases in VTCN1 (B7-H4 gene) and HHLA2 were associated with LUAD with EGFR-activating mutations. Immunohistochemical staining studies further supported that PD-L1 was downregulated and B7-H4 was upregulated in the subtype. Furthermore, PD-L1 expression was positively associated with levels of CD8A and granzyme B, while B7-H4 expression was negatively associated with granzyme B levels. In lung cancer cell lines, EGFR-activating mutations effectively upregulated B7-H4 and downregulated PD-L1. MEK/ERK-pathway activation upregulated B7-H4, and PI3K/Akt activation upregulated PD-L1. EGFR 19Del mutation was associated with inhibition of CD8+ T-cell function, while knocking down B7-H4 could reverse the inhibition, and further showed tumor-growth inhibition and longer survival in vivo. Taken together, this study shed light on that B7-H4 might be an alternative immune-checkpoint molecule and a potential therapeutic target for LUAD with EGFR MT.

Patients harboring uncommon EGFR exon 19 deletion-insertion mutations respond well to first-generation EGFR inhibitors and osimeritinib upon acquisition of T790M

BackgroundIn the existing next generation sequencing (NGS) system, epidermal growth factor receptor (EGFR) exon 19 deletion-insertion (19delins) is still interpreted into the category of EGFR exon 19 deletion (19del). However, the controversy exists whether the two mutation types have the similar responses and resistant mechanisms to first-generation EGFR tyrosine kinase inhibitor (TKI) in non-small cell lung cancer (NSCLC) patients.MethodsWe successively and retrospectively reviewed the NGS data of 3054 patients diagnosed as advanced NSCLC from November 2017 to September 2020. Finally, 41 patients with EGFR 19delins mutation and 41 patients with EGFR 19del mutation who received first-generation EGFR TKIs as first-line therapy were included in the study.ResultsA total of 17 genotypes were identified in this study, including L747_P753delinsS (10/41), L747_A750delinsP (9/41), L747_T751delinsP (6/41) and E746_S752delinsV (3/41). Under the same baseline characteristics, the population of EGFR 19delins respond well to first line EGFR TKIs as well as those of EGFR 19del, with little difference in median progression-free survival (mPFS): 10.4 months vs. 13.1 months, p = 0.1076). Interestingly, patients with L747_T751delinsP seem to have a better mPFS than others (18.7 months vs. 13.1 months, p = 0.035). After the disease progression, both EGFR 19delins and EGFR 19del had similar rates of developing EGFR T790M mutation resistance (45.8% vs. 57.8%), and those receiving osimeritinib as second-line treatment obtain the similar survival benefits (mPFS: 12.0 months vs. 12.2 months (p = 0.97).ConclusionsThis retrospective cohort study furnish the evidence that therapeutic responses and survival of untreated NSCLC population with EGFR 19delins mutation are equal to those with common EGFR 19del mutation after administration of EGFR TKIs therapy.

Efficacy of Icotinib, an EGFR Tyrosine Kinase Inhibitor in Non-Small Cell Lung Cancer Patients with Exon 19 Deletion and Exon 21 L858R: A Retrospective Analysis in China

Introduction: The effect of icotinib on non-small cell lung cancer (NSCLC) patients with EGFR exon 19 deletions (19-Del) or L858R point mutation in exon 21 (21-L858R) remains inconsistent. This study aimed to evaluate the efficacy and safety of icotinib in patients with advanced NSCLC harboring these 2 EGFR mutations. Methods: We retrospectively assessed the clinical effects of first-line icotinib on advanced NSCLC patients with 2 classic EGFR mutations. Kinase activity assays were used to reaffirm the preclinical efficacy. Results: Among 2,757 patients, 2,365 (86%) harbored 19-Del (1,346/2,757, 49%) or 21-L858R (1,019/2,757, 37%) mutation. Patients with 19-Del had a higher response rate (ORR; 67.8 vs. 62.1%; p = 0.0039) and disease control rate (98.5 vs. 97.2%; p = 0.0223) than those with 21-L858R mutation. The median progression-free survival (PFS) in the 19-Del group (22.3 months, 95% confidence interval [CI]: 21.3–23.4) was significantly longer than that in the 21-L858R group (20.4 months, 95% CI: 19.5–21.7) (p = 0.004). In multivariate analysis, mutation types, clinical stage, and smoking history were significant factors for PFS. Additionally, an in vitro study indicated the 50% inhibitory concentrations (IC₅₀) of icotinib was lower for EGFR 19-Del than 21-L858R. Conclusion: These results suggest that EGFR 19-Del confers superior PFS and response to the icotinib treatment compared to 21-L858R.