EGFR-positive Non-small Cell Lung Cancer Research Articles

MMAP-11 VOLUMETRIC STUDY OF BRAIN METASTASES IN EGFR-POSITIVE NSCLC TREATED WITH OSIMERTINIB WITH OR WITHOUT CNS-DIRECTED RADIATION THERAPY

BACKGROUNDIn patients with brain metastases (BM) from EGFR-positive non-small cell lung cancer (NSCLC), recent data indicated that treating with CNS-penetrant tyrosine kinase inhibitors such as osimertinib may enable deferring radiotherapy (RT) in select patients. The purpose of this study was to describe the radiographic response of newly diagnosed BM to osimertinib with or without stereotactic radiosurgery or whole brain radiotherapy, to identify parameters that may guide early versus delayed salvage RT. METHODSIn this single-institution retrospective study, 35 patients with 186 newly diagnosed BM started on osimertinib between 2014 and 2020 were reviewed. BM with tumor volume ≥ 0.1 cm3 were included in the volumetric analyses (N=106 BM). Survival was estimated with the Kaplan-Meier method, and univariable analysis was performed using log-rank tests. Cox proportional hazards was used for multivariable analyses for local control (LC), distant brain failure (DBF), and overall survival (OS). RESULTSOf the 35 patients, 8 (23%) received osimertinib alone. Median follow-up was 29 months. The 1- and 2-year LC rates were 94% and 86%. The 1- and 2-year OS rates were 89% and 66%. Median time to DBF was 24 months. Patients treated with osimertinib and RT were more likely to have a significant radiographic volumetric response at early follow-up (4-12 weeks after treatment initiation) compared to osimertinib alone (median volumetric response of –80% vs. –41%, p=0.05). On per lesion analysis, early volumetric response of ≥ 80% was associated with improved LC (3-year LC 98% vs 72%, p=0.04). CONCLUSIONSThe combination of osimertinib and CNS RT is associated with greater early volumetric response in patients with BM from EGFR-positive NSCLC compared to osimertinib alone. BM with significant initial radiographic response remain well-controlled in the long term. Patients whose BM demonstrate limited initial volumetric response may benefit from targeted RT to provide long term control.

Pyrimidine derivatives as EGFR tyrosine kinase inhibitors in non-small-cell lung cancer: A comprehensive review.

EGFR-positive non-small-cell lung cancer (NSCLC) due to primary mutation (EGFR DEL19 & L858R) has been recognized as a crucial mediator of tumor progression. This led to the development and approval of EGFR tyrosine kinase inhibitors, which addresses EGFR-mediated NSCLC but fail to show potency after initial months of therapy due to acquired resistance (EGFR T790M, EGFR C797S). Extensive research allowed identification of drugs for EGFR-positive NSCLC, wherein the majority of compounds have a pyrimidine substructure offering marked therapeutic benefits compared with chemotherapy. This current review outlines the diverse pyrimidine derivatives with amino-linked and fused pyrimidine scaffolds such as furo-pyrimidine, pyrimido-pyrimidine, thieno-pyrimidine, highlighting pyrimidine EGFR TK inhibitors reported in research emphasizing structural aspects, design approaches, inhibition potential, selectivity profile toward mutant EGFR conveyed through biological evaluation studies. Furthermore, mentioning the in-silico interaction profile of synthesized compounds for evaluating the binding affinity with key amino acids. The epilogue of review focuses on the recent research that drives forward to aid in the discovery and development of substituted amino and fused scaffolds of pyrimidine that can counteract the mutations and effectively manage EGFR-positive NSCLC.

Ras-Related Protein Rab-32 and Thrombospondin 1 Confer Resistance to the EGFR Tyrosine Kinase Inhibitor Osimertinib by Activating Focal Adhesion Kinase in Non-Small Cell Lung Cancer.

Simple SummaryOsimertinib is a third-generation EGFR tyrosine kinase inhibitor and the standard of care therapy for non-small cell lung cancer patients harboring EGFR-activating mutations. However, even for patients treated with osimertinib, resistance inevitably occurs leading to disease progression. Here, we utilized two osimertinib-resistant cell lines and investigated their RNA profiles. We found that Ras-related protein Rab-32 (RAB32) and thrombospondin 1 (THBS1) were upregulated and associated with resistance in osimertinib-resistant cells as well as in liquid biopsies from patients with disease progression following osimertinib treatment. Moreover, we found RAB32 and THBS1 to be mechanistically linked to activation of the focal adhesion pathway where combination of osimertinib with a FAK inhibitor resulted in a synergistic suppression of viability of osimertinib-resistant cells. Our findings propose a potential therapeutic strategy for overcoming acquired resistance to osimertinib in non-small cell lung cancer.Treatment with the tyrosine kinase inhibitor (TKI) osimertinib is the standard of care for non-small cell lung cancer (NSCLC) patients with activating mutations in the epidermal growth factor receptor (EGFR). Osimertinib is also used in T790M-positive NSCLC that may occur de novo or be acquired following first-line treatment with other EGFR TKIs (i.e., gefitinib, erlotinib, afatinib, or dacomitinib). However, patients treated with osimertinib have a high risk of developing resistance to the treatment. A substantial fraction of the mechanisms for resistance is unknown and may involve RNA and/or protein alterations. In this study, we investigated the full transcriptome of parental and osimertinib-resistant cell lines, revealing 131 differentially expressed genes. Knockdown screening of the genes upregulated in resistant cell lines uncovered eight genes to partly confer resistance to osimertinib. Among them, we detected the expression of Ras-related protein Rab-32 (RAB32) and thrombospondin 1 (THBS1) in plasmas sampled at baseline and at disease progression from EGFR-positive NSCLC patients treated with osimertinib. Both genes were upregulated in progression samples. Moreover, we found that knockdown of RAB32 and THBS1 reduced the expression of phosphorylated focal adhesion kinase (FAK). Combination of osimertinib with a FAK inhibitor resulted in synergistic toxicity in osimertinib-resistant cells, suggesting a potential therapeutic drug combination for overcoming resistance to osimertinib in NSCLC patients.

MO45-3 The efficacy of osimertinib in patients with EGFR-positive non-small cell lung cancer with malignant pleural effusion

Malignant pleural effusion (MPE) is considered to be one of the poor predictive factors in epidermal growth factor receptor (EGFR) mutation-positive non-small-cell lung cancer (NSCLC). However, the efficacy of osimertinib for patients with MPE has not been clarified.

Abstract 5768: Genomic characteristics of classic and uncommon EGFR activating mutations explains different responses to first-generation EGFR-TKIs

Abstract Background: Classic sensitizing mutations of epidermal growth factor receptor (cEGFR) (i.e., exon 19 deletions and exon 21 L858R) have shown positive responses to first-generation TKIs in non-small cell lung cancer (NSCLC). For patients with uncommon EGFR mutations (uEGFR), such as G719X, S768I, L861Q and exon 20 insertions, first-generation TKIs might still be one of the mainstay choices in clinic. However, they exhibited heterogeneity in treatment responses. Here, we aimed to elucidate different genomic profiles of tumors carrying uncommon EGFR activating mutations to explain differential treatment responses. Method: We screened 6669 NSCLC patients that underwent targeted NGS of 416 cancer-related genes. Total 2280 EGFR-positive NSCLCs were selected for analysis. We compared somatic mutations, tumor mutation burden (TMB), mutational signature and canonical oncogenic pathways between cEGFR and uEGFR. A validation set of 159 NSCLCs from the Cancer Genome Atlas (TCGA) was used. Adjusted p value less than 0.1 were considered statistically significant. Results: Only patients carrying known EGFR activating mutations and without complex mutations were included. The final cohort comprised 1022 patients with L858R (44.8%), 973 with exon 19 deletion (42.7%), 139 with exon 20 insertion (6.1%), 59 with G719X (2.6%), 51 with L861Q (2.2%), and 36 with S768I (1.6%). In general, clinical features were equally distributed except for higher prevalence of G719X and S768I in male. Most frequently co-mutated genes were similar between cEGFR and uEGFR subgroups, including TP53 (56% vs 60%), PIK3CA (8% vs 11%), and RB1 (8% vs 9%). Despite these, we found enrichment of EPHA3 and MED12 with S768I(both 5/36, 14%)as compared to with cEGFR (2% vs 3%, padj<0.1), while GATA6 predominantly co-occurred with L861Q (4/51, 8%,). Overall, patients carrying uEGFR had significantly higher TMB than those with cEGFR (median TMB 5.07 vs 3.80, p=0.0076), indicating more complicated clonal backgrounds that potentially led to the poor TKI response. Among the ten oncogenic pathways, the hippo pathway markedly more altered more in those with uEGFR than with cEGFR (p=0.0025). Moreover, we found higher fraction of immunoglobulin-related signature (signature 9) and BRCA1/2-associated signature (signature 3) in tumors with cEGFR than with uEGFR (p = 0. 0003 and 0. 02, respectively). Importantly, smoking induced mutations (signature 4) were enriched in uEGFR subgroup (p = 0. 0015), which was also verified in TCGA samples. Further, 28 patients had confirmed treatment with first-generation TKIs, where uEGFR were associated with poor outcomes (HR = 1.43, 95% CI 0.81-2.52). Conclusion: This comprehensive analysis of EGFR-positive mutational landscape revealed specific genomic characteristics associated with uncommon EGFR mutations that might explain their poor response to first-generation TKIs. Citation Format: Xue Wu, Junli Zhang, Jingwen Liu, Yedan Chen, Yang Shao. Genomic characteristics of classic and uncommon EGFR activating mutations explains different responses to first-generation EGFR-TKIs [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5768.

Driver mutations and air pollution in advanced non-small cell lung cancer (NSCLC) at two reference hospitals in Mexico City.

e20545 Background: Currently, precision medicine has allowed the classification of NSCLC according to the profile of driver mutations and the development of highly effective treatments. There is evidence to support the relationship between outdoor air pollution, particularly particulate matter (PM) in outdoor air, with lung cancer incidence and mortality. Smoking is a negative predictor of EGFR mutation, but the effect of air pollution has not been stablished. Methods: We perform a retrospective study in two referral hospitals in Mexico City between 2015 to 2020 to determinate the frequency of key driver mutations in patients with advanced NSCLC and the relation with smoking habit, wood smoke exposure and pollution indexes (PM2.5, PM10, SO2, O3, NO2) according to their place of residence. We used WHO air quality thresholds for air pollutants to classify cases with high or low exposure. Results: A total of 1277 cases were analyzed. The median age at diagnosis was 66 years (range 18-97 years), 53% were females and 49.6% had history of smoking habit. According to histology, 61.6% of cases corresponded to adenocarcinoma, 11.7% were squamous, 1.3% large cell, and 25.4% indeterminate. Wood smoke was assessed in 83.1% of cases and 28.5% had exposure history. Air pollutants were measured in half of cases, high level of exposure for PM2.5, PM10, NO2 and SO2 occurred in 63.2%, 30.8%, 15.6%, 53.4%, respectively. EGFR, ALK and KRAS mutations were evaluated in 85%, 16.7% and 8.6% of patients, respectively. The presence of these mutations was: EGFR 17.1%, ALK 11.1%, and KRAS 16.5%. Patients with EGFR-positive NSCLC were more frequently female (65.1% vs 34.9%, OR 1.8 95%CI 1.4-2.5, p < 0.001) and had no history of tobacco use (35% vs 65%, OR 0.49 95%CI 0.36-0.67, p < 0.001). Wood smoke was not statistically significant. High exposure to PM2.5 was most common in patients with non-mutated EGFR NSCLC (65.3% vs 34.7%, OR 1.7 95%CI 1.2-2.5, p = 0.006). Relationship with other air pollutants were not statistically significant. ALK-positive NSCLC patients tend to be females (68% vs 32%, p = 0.07) and had no history of smoking habit (20.8% vs 79.2% OR 0.28 95%CI 0.1-0.78, p = 0.01). High exposure to SO2 was common (78.6% vs 21.4% p = 0.05). Association in KRAS-positive NSCLS patients were not found. Conclusions: A low rate of key driver mutations assessment was found in this Mexican cohort. Clinical profile of NSCLC EGFR positive is according with previous reports in the literature. Exposure to PM2.5 and SO2 were found associated with EGFR and ALK status in this retrospective study and are hypothesis generating information.

High-dose icotinib in advanced lung adenocarcinoma(LUAD) patients harboring EGFR exon 21 L858R mutation: Real-world (RW) experience in a single center.

e21036 Background: Non-small cell lung cancer(NSCLC) patients(pts) with epidermal growth factor receptor (EGFR) exon 19 deletion have more benefit from EGFR-tyrosine kinase inhibitors(EGFR-TKIs) compared to pts with EGFR exon 21 L858R mutation. Icotinib, which is a first-generation EGFR-TKI had been approved for use in EGFR-positive advanced NSCLC pts. A phase II trial(INCREASE trial) showed that high-dose icotinib 250mg tid(ico250) can effectively prolong the progression-free survival(PFS) of NSCLC pts with exon 21 L858R mutation without increased toxicity. However, the RW evidence is lacking. Methods: In this single-center, single-arm study, data were retrospectively collected from China-Japan Friendship Hospital. Pts with advanced LUAD, harboring EGFR exon 21 L858R mutation, and who received ico250 for more than 20 days without chemotherapy or immunotherapy were reviewed. Clinical data were analyzed for PFS, objective response rate(ORR), disease control rate(DCR), overall survival(OS), duration of treatment(DoT) and adverse events(AEs). Survival factors were evaluated by univariate and multivariate Cox regression analysis. Results: In total 40 pts(14M,26F; median age 67[46-86]; smoker:20.0%; ECOG performance status 0-1/2-3: 33/7) who received ico250 between 4/2019-11/2021 were analyzed. The median line of pre-ico therapies was 1(range 0-2). At the cut-off day, 29(72.5%) pts had discontinued ico250, and 7(17.5%) pts died. Overall, ORR was 30.0%, DCR was 80.0%, median DoT was 8.0mos (95%CI, 3.4-12.6), median PFS was 12.9mos (95%CI, 8.2-17.6) and median OS was not reached. The univariate and multivariate analysis showed that there was no significant and independent factor associated with PFS(all P> 0.05). 30(75.0%) pts experienced AEs, while the most common AEs were rash(24,60.0%), dry skin(9,22.5%), paronychia(8,20.0%) and diarrhea(6,15.0%). Grade 3/4 AEs in 6(15.0%) pts included AST/ALT elevation(3,7.5%), rash(2,5%), diarrhea(1,2.5%) and mucositis(1,2.5%)(1 suffered both rash and mucositis). 5(12.5%) pts discontinued high-dose icotinib due to AEs. Conclusions: These data add to the RW evidence that the efficacy and tolerability of ico250 in advanced LUAD pts harboring EGFR exon 21 L858R mutation. The efficacy results are consistent with the previous INCREASE trial. High-dose icotinib could be considered whatever the previous treatment and basic characteristics of LUAD pts with exon 21 L858R mutation. However, the higher incidence of grade3/4 AEs deserves special attention.

Efficacy and Safety of Gefitinib Plus Anlotinib for Patients with EGFR Positive Advanced Non-Small-Cell Lung Cancer: A Retrospective Exploratory Study.

ObjectiveThis study was to investigate the efficacy and safety of gefitinib plus anlotinib for patients with EGFR positive advanced non-small cell lung cancer (NSCLC) in a first-line setting.MethodsA total of 36 patients with previously-untreated EGFR positive advanced NSCLC were included in this study retrospectively. All patients were administered with gefitinib plus anlotinib combination therapy. The efficacy of the patients was evaluated with the change of target lesion using imaging evidence according to RECIST 1.1 criteria and all the patients were followed up regularly. Adverse reactions were collected and documented during the combination administration. Univariate analysis according to the baseline characteristic subgroup was implemented using Log rank test and multivariate analysis was adjusted by Cox regression analysis.ResultsAll the 36 patients included in our study were available for efficacy and safety analysis. Best overall response of the patients during gefitinib plus anlotinib administration suggested that partial response was observed in 30 patients, stable disease was noted in five patients, and progressive disease was found in one patient, which yielded an objective response rate (ORR) of 83.3% (95% CI=67.2–93.6%) and a disease control rate (DCR) of 97.2% (95% CI=85.5–99.9%). Prognostic data indicated that the median progression-free survival (PFS) of the 36 patients with NSCLC was 15.2 months (95% CI=8.15–22.26). Furthermore, the median overall survival (OS) of the 36 patients was 35.9 months (95% CI=22.77–49.03). Additionally, the most common adverse reactions of the patients with NSCLC were diarrhea (63.9%), fatigue (58.3%), hypertension (50.0%), rash (44.4%), and nausea and vomiting (41.7%). Furthermore, ECOG performance status was associated with PFS of gefitinib plus anlotinib combination therapy in baseline characteristic subgroup analysis.ConclusionGefitinib plus anlotinib regimen demonstrated encouraging efficacy and an acceptable safety profile for patients with previously untreated EGFR positive NSCLC preliminarily. The conclusion should be validated in prospective clinical trials subsequently.

Prevalence of Epidermal Growth Factor Receptor Exon 20 Insertion Mutations in Non-small-Cell Lung Cancer in Europe: A Pragmatic Literature Review and Meta-analysis.

BackgroundInformation on the epidemiology of uncommon EGFR mutations including exon 20 insertions amongst non-small-cell lung cancer (NSCLC) is lacking.ObjectiveThe objective of this pragmatic literature review (PLR) and meta-analysis was to generate robust prevalence and incidence estimates based on ranges of exon 20 insertion mutations reported in the literature.Materials and methodsSearches of MEDLINE, Embase, congresses and reference lists for articles published from 2013 in key European countries of interest (Belgium, France, Germany, Italy, The Netherlands, Spain, Sweden, Switzerland, United Kingdom) were performed. Articles were reviewed against pre-specified criteria and their quality was appraised using a published checklist. Prevalence estimates were synthesised by random-effects meta-analyses.ResultsEighty unique studies of moderate-to-high quality were included in the PLR. The meta-analysed prevalence for EGFR mutations was 12.5% (95% confidence interval [CI]: 11.0, 14.1) in any stage NSCLC and 14.8% (12.8, 17.1) in advanced/metastatic NSCLC. The prevalence of exon 20 insertions was 0.7% (0.4, 1.1) in any stage NSCLC and 6.1% (4.0, 9.4) in any stage EGFR-positive NSCLC. Mutation status was primarily measured using direct sequencing or a combination of methods. One study reporting exon 20 insertions in advanced/metastatic disease was identified, which reported a prevalence of 0.5% in overall NSCLC and 4.0% in EGFR-positive NSCLC.ConclusionsEGFR exon 20 insertion mutations are rare in NSCLC. There is a high unmet need in patients with exon 20 insertions, including effective therapies. Prospective cohort studies are needed to better clinically characterise these patients.Supplementary InformationThe online version contains supplementary material available at 10.1007/s11523-022-00868-z.

Premetastatic shifts of endogenous and exogenous mutational processes support consolidative therapy in EGFR-driven lung adenocarcinoma.

The progression of cancer is an evolutionary process that is challenging to assess between sampling timepoints. However, investigation of cancer evolution over specific time periods is crucial to the elucidation of key events such as the acquisition of therapeutic resistance and subsequent fatal metastatic spread of therapy-resistant cell populations. Here we apply mutational signature analyses within clinically annotated cancer chronograms to detect and describe the shifting mutational processes caused by both endogenous (e.g. mutator gene mutation) and exogenous (e.g. mutagenic therapeutics) factors between tumor sampling timepoints. In one patient, we find that cisplatin therapy can introduce mutations that confer genetic resistance to subsequent targeted therapy with Erlotinib. In another patient, we trace detection of defective mismatch-repair associated mutational signature SBS3 to the emergence of known driver mutation CTNNB1 S37C. In both of these patients, metastatic lineages emerged from a single ancestral lineage that arose during therapy-a finding that argues for the consideration of local consolidative therapy over other therapeutic approaches in EGFR-positive non-small cell lung cancer. Broadly, these results demonstrate the utility of phylogenetic analysis that incorporates clinical time course and mutational signature deconvolution to inform therapeutic decision making and retrospective assessment of disease etiology.

Upfront Treatment With Osimertinib vs. Osimertinib and Radiotherapy for Patients With EGFR-Positive Non-Small Cell Lung Cancer Brain Metastases

<h3>Purpose/Objective(s)</h3> Given the improved central nervous system penetration of 3^rd generation tyrosine kinase inhibitors, such as osimertinib, the role of upfront radiation therapy (RT) in the setting of brain metastases (BM) has been brought into question. We sought to retrospectively evaluate outcomes at our institution for patients with EGFR-positive NSCLC treated with osimertinib as the upfront treatment for new or progressing BM versus osimertinib in combination with intracranial RT. <h3>Materials/Methods</h3> This single-institution retrospective analysis of EGFR-positive NSCLC with new or progressing BM included a total of 92 patients with 405 BM treated between 2013 to 2021 and followed until July 2021. Two BM treatment groups were evaluated: (1) patients treated with upfront osimertinib alone (n=58), and (2) patients treated with osimertinib combined with RT [either whole brain radiation therapy (WBRT) or stereotactic radiosurgery (SRS) prior or concurrently with osimertinib (n=34)]; both groups began treatment within 2 months of BM diagnosis. Time-to-event analysis was conducted with the Kaplan-Meier (KM) method, and outcomes included distant intracranial control (DIC), local control (LC), and overall survival (OS). Cox proportional hazards model was utilized for multivariate analysis (MVA) to identify correlations of clinical outcomes. <h3>Results</h3> Median follow-up from BM diagnosis was 13.2 months (0.8-48.9 months). Of the patients treated with osimertinib and RT, 17 were treated with SRS and 17 with WBRT. No significant differences in age (p=0.96), gender (p=0.42), DS-GPA (p=0.73), KPS (p=0.54, number (p=0.52) or volume (p=0.29) of BM, SRS dose (p=0.44), or number of systemic metastases (p=0.88) were noted between groups. No difference between osimertinib vs osimertinib and RT groups was noted for 12 month KM rates of DIC 84.9% and 68.7% (p=0.80); LC 99.6% and 93.1% (p=0.31); and OS 66% and 73.5% (p=0.). Of the 58 patients treated with upfront osimertinib, 19 patients with 77 lesions eventually required radiation for intracranial progression with 62 of those lesions being treated with SRS. Upon MVA, higher KPS (p=.001) and DS-GPA (p=0.002) were associated with increased OS and systemic metastasis at time of treatment with worse OS (p=0.001). <h3>Conclusion</h3> The results of this study support other preliminary data suggesting that upfront osimertinib alone may provide sufficient intracranial control to allow RT to be deferred until further intracranial progression. Prospective trials are needed to further guide treatment.

Evaluate the Prognosis of MYC/TP53 Comutation in Chinese Patients with EGFR-Positive Advanced NSCLC Using Next-Generation Sequencing: A Retrospective Study.

Purpose: The purpose of this study was to investigate the effect of MYC and TP53 comutations on the clinical efficacy of EGFR tyrosine kinase inhibitors (TKIs) in Chinese patients with advanced EGFR-positive nonsmall-cell lung cancer (NSCLC). Patients and methods: Tissue samples and information from 65 patients with advanced NSCLC in Northern Jiangsu People's Hospital were collected and analyzed by next-generation sequencing (NGS). Progression-free survival (PFS) and total survival (OS) were the main endpoints, and the objective response rate (ORR) and disease control rate (DCR) were the secondary endpoints. Result: Among 65 patients, 17 had TP53 and MYC wild-type mutations (WT/WT), 36 had TP53 mutant and MYC wild-type mutations (TP53/WT), and 12 had coexisting MYC/TP53 mutations (MYC/TP53). When 12 patients with MYC/TP53 comutation were compared with the other two groups (TP53/WT, WT/WT), mPFS and mOS are significantly lower than those in the other two groups (mPFS: 4.1 months vs 6.0 months, 12.3 months, HR: 0.769, 95% CI: 4.592-7.608, P = .047. mOS: 14.6 months vs 24.1 months, 31.5 months, HR: 3.170, 95% CI: 18.786-31.214, P < .001), and the ORR, DCR of patients with MYC/TP53 comutation was lower than that of the other two groups (ORR, 25% vs 44.4%, 70.6%, P = .045. DCR, 58.3% vs 72.2%, 82.4%, P = .365). Conclusion: Patients with MYC/TP53 comutations with EGFR-positive advanced NSCLC are more likely to develop drug resistance after early treatment with EGFR-TKIs and have a worse clinical outcome.

Therapeutic effect of osimertinib plus cranial radiotherapy compared to osimertinib alone in NSCLC patients with EGFR-activating mutations and brain metastases: a retrospective study

BackgroundThe study aimed to compare the efficacy of osimertinib plus cranial radiotherapy (RT) with osimertinib alone in advanced non-small-cell lung cancer (NSCLC) patients harboring epidermal growth factor receptor (EGFR) mutations and brain metastases (BMs).MethodsThe clinical data of advanced NSCLC patients with BMs who received osimertinib were retrospectively collected. The patients were assigned to one of the two groups according to the therapeutic modality used: the osimertinib monotherapy group or the osimertinib plus RT group.ResultsThis was a retrospective study and 61 patients were included from December 2015 to August 2020. Forty patients received osimertinib monotherapy, and twenty-one patients received osimertinib plus RT. Radiotherapy included whole-brain radiation therapy (WBRT, n = 14), WBRT with simultaneous integrated boost (WBRT-SIB, n = 5) and stereotactic radiosurgery (SRS, n = 2). The median number of prior systemic therapies in the two groups was one. Intracranial and systemic ORR and DCR were not significantly different between the two groups. No difference in iPFS was observed between the two groups (median iPFS: 16.67 vs. 13.50 months, P = 0.836). The median OS was 29.20 months in the osimertinib plus RT group compared with 26.13 months in the osimertinib group (HR = 0.895, P = 0.826). In the L858R mutational subgroup of 31 patients, the osimertinib plus RT group had a longer OS (P = 0.046). In the exon 19 deletion mutational subgroup of 30 patients, OS in the osimertinib alone group was longer than that in the osimertinib plus RT group (P = 0.011). The incidence of any-grade adverse events was not significantly different between the osimertinib plus RT group and the osimertinib alone group (47.6% vs. 32.5%, P = 0.762). However, six patients (28.5%) experienced leukoencephalopathy in the osimertinib plus RT group, and 50% (3/6) of the leukoencephalopathy was greater than or equal to grade 3.ConclusionThe therapeutic effect of osimertinib with RT was similar to that of osimertinib alone in EGFR-positive NSCLC patients with BM. However, for patients with the L858R mutation, osimertinib plus RT could provide more benefit than osimertinib alone.

Association of Clinicopathologic and Molecular Tumor Features With Recurrence in Resected Early-Stage Epidermal Growth Factor Receptor–Positive Non–Small Cell Lung Cancer

The recently published ADAURA study has posed a significant dilemma for clinicians in selecting patients for adjuvant osimertinib. Risk factors for recurrence in early-stage epidermal growth factor receptor (EGFR)-positive non-small cell lung cancer (NSCLC) also remain undefined. To determine clinicopathologic characteristics and recurrence patterns of resected early-stage EGFR-positive NSCLC, using wildtype EGFR as a comparator cohort, and identify features associated with recurrence. This is a cohort study including patients diagnosed with AJCC7 Stage IA to IIIA NSCLC between January 1, 2010, and June 30, 2018, who underwent curative surgical procedures at a specialist cancer center in Singapore. The cutoff for data analysis was October 15, 2020. Patient demographic characteristics, treatment history, and survival data were collated. In exploratory analysis, whole-exome sequencing was performed in a subset of 86 patients. Data were analyzed from September 3, 2020, to June 6, 2021. Adjuvant treatment was administered per investigator's discretion. The main outcome was 2-year disease-free survival (DFS). A total of 723 patients were included (389 patients with EGFR-positive NSCLC; 334 patients with wildtype EGFR NSCLC). There were 366 women (50.6%) and 357 men (49.4%), and the median (range) age was 64 (22-88) years. A total of 299 patients (41.4%) had stage IA NSCLC, 155 patients (21.4%) had stage IB NSCLC, 141 patients (19.5%) had stage II NSCLC, and 125 patients (17.3%) had stage IIIA NSCLC. Compared with patients with wildtype EGFR NSCLC, patients with EGFR-positive NSCLC were more likely to be women (106 women [31.7%] vs 251 women [64.5%]) and never smokers (121 never smokers [36.2%] vs 317 never smokers [81.5%]). At median (range) follow up of 46 (0-123) months, 299 patients (41.4%) had cancer recurrence. There was no statistically significant difference in 2-year DFS for EGFR-positive and wildtype EGFR NSCLC (70.2% [95% CI, 65.3%-74.5%] vs 67.6% [95% CI, 62.2%-72.4%]; P = .70), although patients with EGFR-positive NSCLC had significantly better 5-year overall survival (77.7% [95% CI, 72.4%-82.1%] vs 66.6% [95% CI, 60.5%-72.0%]; P = .004). Among patients with EGFR-positive NSCLC, 2-year DFS was 81.0% (95% CI, 74.0%-86.3%) for stage IA, 78.4% (95% CI, 68.2%-85.6%) for stage IB, 57.1% (95% CI, 43.7%-68.4%) for stage II, and 46.6% (95% CI, 34.7%-57.7%) for stage IIIA. Overall, 5-year DFS among patients with stage IB through IIIA was 37.2% (95% CI, 30.1%-44.3%). Sites of disease at recurrence were similar between EGFR-positive and wildtype EGFR NSCLC, with locoregional (64 patients [16.5%] vs 56 patients [16.8%]), lung (41 patients [10.5%] vs 40 patients [12.0%]), and intracranial (37 patients [9.5%] vs 22 patients [6.6%]) metastases being the most common. A risk estimation model incorporating genomic data and an individual patient nomogram using clinicopathologic features for stage I EGFR-positive NSCLC was developed to improve risk stratification. This cohort study found that recurrence rates were high in early-stage EGFR-positive NSCLC including stage IA, yet 37.2% of patients with stage IB through IIIA were cured without adjuvant osimertinib. Further studies are needed to elucidate individualized surveillance and adjuvant treatment strategies for early-stage EGFR-positive NSCLC.

KRAS p.G12C mutation occurs in 1% of EGFR-mutated advanced non-small-cell lung cancer patients progressing on a first-line treatment with a tyrosine kinase inhibitor

BackgroundKRAS is mutated in ∼30% of non-small-cell lung cancer (NSCLC) but it has also been identified as one of the mechanisms underlying resistance to tyrosine kinase inhibitors (TKIs) in EGFR-positive NSCLC patients. Novel KRAS inhibitors targeting KRAS p.G12C mutation have been developed recently with promising results. The proportion of EGFR-positive NSCLC tumours harbouring the KRAS p.G12C mutation upon disease progression is completely unexplored.Materials and methodsPlasma samples from 512 EGFR-positive advanced NSCLC patients progressing on a first first-line treatment with a TKI were collected. The presence of KRAS p.G12C mutation was assessed by digital PCR.ResultsOverall, KRAS p.G12C mutation was detected in 1.17% of the samples (n = 6). In two of these cases, we could confirm that the KRAS p.G12C mutation was not present in the pre-treatment plasma samples, supporting its role as an acquired resistance mutation. According to our data, KRASG12C patients showed similar clinicopathological characteristics to those of the rest of the study cohort and no statistically significant associations between any clinical features and the presence of the mutation were found. However, two out of six KRASG12C tumours harboured less common EGFR driver mutations (p.G719X/p.L861Q). All KRASG12C patients tested negative for the presence of p.T790M resistance mutation.ConclusionsThe KRAS p.G12C mutation is detected in 1% of EGFR-positive NSCLC patients who progress on a first line with a TKI. All KRASG12C patients were negative for the presence of the p.T790M mutation and they did not show any distinctive clinical feature.

R-Score: A New Parameter to Assess the Quality of Variants' Calls Assessed by NGS Using Liquid Biopsies.

Simple SummaryCirculating tumor DNA profiling by next-generation sequencing (NGS) is becoming essential for guiding targeted therapies. However, it remains challenging. Here, we show that variant allele fraction and the median of absolute values of all pairwise differences impact the agreement between digital PCR and NGS calls. Therefore, we propose a new parameter, named R-score, which integrates both variables, and we evaluate its usefulness for optimizing NGS variant calling.Next-generation sequencing (NGS) has enabled a deeper knowledge of the molecular landscape in non-small cell lung cancer (NSCLC), identifying a growing number of targetable molecular alterations in key genes. However, NGS profiling of liquid biopsies risk for false positive and false negative calls and parameters assessing the quality of NGS calls remains lacking. In this study, we have evaluated the positive percent agreement (PPA) between NGS and digital PCR calls when assessing EGFR mutation status using 85 plasma samples from 82 EGFR-positive NSCLC patients. According to our data, variant allele fraction (VAF) was significantly lower in discordant calls and the median of the absolute values of all pairwise differences (MAPD) was significantly higher in discordant calls (p < 0.001 in both cases). Based on these results, we propose a new parameter that integrates both variables, named R-score. Next, we sought to evaluate the PPA for EGFR mutation calls between two independent NGS platforms using a subset of 40 samples from the same cohort. Remarkably, there was a significant linear correlation between the PPA and the R-score (r = 0.97; p < 0.001). Specifically, the PPA of samples with an R-score ≤ −1.25 was 95.83%, whereas PPA falls to 81.63% in samples with R-score ≤ 0.25. In conclusion, R-score significantly correlates with PPA and can assist laboratory medicine specialists and data scientists to select reliable variants detected by NGS.

Irradiation Suppresses IFNγ-Mediated PD-L1 and MCL1 Expression in EGFR-Positive Lung Cancer to Augment CD8+ T Cells Cytotoxicity.

Tumor cells express immune checkpoints to exhaust CD8+ T cells. Irradiation damages tumor cells and augments tumor immunotherapy in clinical applications. However, the radiotherapy-mediated molecular mechanism affecting CD8+ T cell activity remains elusive. We aimed to uncover the mechanism of radiotherapy augmenting cytotoxic CD8+ T cells in non-small-cell lung cancer (NSCLC). EGFR-positive NSCLC cell lines were co-cultured with CD8+ T cells from healthy volunteers. Tumor cell viability and apoptosis were consequently measured. IFNγ was identified secreted by CD8+ T cells and PBMCs. Therefore, RNAseq was used to screen the IFNγ-mediated gene expression in A549 cells. The irradiation effect to IFNγ-mediated gene expression was investigated using qPCR and western blots. We found that the co-culture of tumor cells stimulated the increase of granzyme B and IFNγ in CD8+ T, but A549 exhibited resistance against CD8+ T cytotoxicity compared to HCC827. Irradiation inhibited A549 proliferation and enhanced apoptosis, augmenting PBMCs-mediated cytotoxicity against A549. We found that IFNγ simultaneously increased phosphorylation on STAT1 and STAT3 in EGFR-positive lung cancer, resulting in overexpression of PD-L1 (p < 0.05). In RNAseq analysis, MCL1 was identified and increased by the IFNγ-STAT3 axis (p < 0.05). We demonstrated that irradiation specifically inhibited phosphorylation on STAT1 and STAT3 in IFNγ-treated A549, resulting in reductions of PD-L1 and MCL1 (both p < 0.05). Moreover, knockdowns of STAT3 and MCL1 increased the PBMCs-mediated anti-A549 effect. This study demonstrated that A549 expressed MCL1 to resist CD8+ T cell-mediated tumor apoptosis. In addition, we found that irradiation suppressed IFNγ-mediated STAT3 phosphorylation and PD-L1 and MCL1 expression, revealing a potential mechanism of radiotherapy augmenting immune surveillance.

Co-delivery of gefitinib and hematoporphyrin by aptamer-modified fluorinated dendrimer for hypoxia alleviation and enhanced synergistic chemo-photodynamic therapy of NSCLC

Although epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs)-based molecular targeted therapy are proved to be effective in the treatment of non-small cell lung cancer (NSCLC) with EGFR mutation, its efficacy is limited by the acquired drug resistance. The combination of EGFR-TKIs with photodynamic therapy (PDT) has been explored to combat NSCLC with promising synergistic results. However, hypoxic tumor microenvironment is associated with the development of EGFR-TKIs resistance and severely limits the efficacy of PDT. Here, we synthesized an aptamer modified fluorinated dendrimer (APF) as a drug carrier and prepared nanocomplexes APFHG by encapsulation of gefitinib (Gef) and hematoporphyrin (Hp). APF has good oxygen-carrying capacity, high drug entrapment efficiency, and could release Gef and Hp in response to intracellular pH. APF can specifically recognize EGFR-positive NSCLC cells and effectively improve the tumor hypoxic microenvironment due to the targeting effect of aptamer and the good oxygen-carrying capacity of the fluorinated dendrimer. Under the laser irradiation, APFHG can significantly increase the production of the intracellular reactive oxygen species and produce a synergistic therapeutic effect in inhibition of cellular growth and induction of cell cycle arrest and apoptosis on both Gef-sensitive and Gef-resistant EGFR-mutant NSCLC cells through PDT/molecular targeted therapy. This work indicates that fluorinated dendrimer could be a potent drug delivery platform to overcome hypoxia-related resistance and the co-delivery of EGFR-TKI and photosensitizer by the fluorinated dendrimer could be a promising therapeutic approach for reversal of EGFR-TKIs resistance in EGFR mutation-positive NSCLC.

Analysis of circulating tumour DNA to identify patients with epidermal growth factor receptor–positive non-small cell lung cancer who might benefit from sequential tyrosine kinase inhibitor treatment

BackgroundSurvival data support the use of first-line osimertinib as the standard of care for epidermal growth factor receptor (EGFR)–positive non-small cell lung cancer (NSCLC). However, it remains unclear whether upfront osimertinib is superior to sequential first- or second-generation tyrosine kinase inhibitors (TKIs) followed by osimertinib for all patients. It is impossible to predict which patients are at high risk of progression, and this constitutes a major limitation of the sequential TKI approach. Patients and methodsA total of 830 plasma samples from 228 patients with stage IV, EGFR-positive NSCLC who were treated with first-line TKIs were analysed by digital polymerase chain reaction (dPCR). ResultsThe circulating tumour DNA (ctDNA) levels helped to identify patients with significantly improved survival rate, regardless of the treatment. Patients treated with first- or second-generation TKIs (N = 189) with EGFR mutations in plasma at a mutant allele frequency (MAF) <7% before treatment initiation (low-risk patients) or who were ctDNA negative after 3 or 6 months of treatment and with an MAF <7% at diagnosis (high responders) had two-thirds lower risk of death than patients in the opposite situation (adjusted hazard ratio [HR] = 0.38; 95% confidence interval [CI]: 0.23–0.64 and HR = 0.22; 95% CI: 0.12–0.42, respectively). The median overall survival (OS) for low-risk patients and high responders treated with first- or second-generation TKIs was 34.2 months and not reached, respectively, regardless of second-line treatment. There were no significant difference in OS between low-risk or high-responder patients treated upfront with osimertinib (N = 39) and those treated under a sequential approach with osimertinib (N = 60). Median OS was not reached in both cases. ConclusionsPre-treatment ctDNA levels identify low-risk patients, who may benefit from sequential TKI treatment. Information regarding EGFR mutation clearance can help to improve patient selection.

P76.36 A Phase 2 Study of Anlotinib Combined with Pemetrexed-Platinum (PP) as Second-Line Treatment in EGFR-Positive Non-Small Cell Lung Cancer (NSCLC)

P76.36 A Phase 2 Study of Anlotinib Combined with Pemetrexed-Platinum (PP) as Second-Line Treatment in EGFR-Positive Non-Small Cell Lung Cancer (NSCLC)