Epidermal Growth Factor Receptor Exon Research Articles

CLINICAL FACTORS PREDECTING T790M MUTATION IN NON-SMALL CELL LUNG CANCER PROGRESSED AFTER FIRST- AND SECOND-GENERATION TKI TREATMENT

Objective: We aimed to identify the T790M mutation rate and clinical factors predicting the occurrence of acquired T790M mutations in advanced non-small cell lung cancer (NSCLC) patients with epidermal growth factor receptor (EGFR) mutations after first- and second-generation tyrosine kinase inhibitor (TKI) treatment. Method: The EGFR-mutant NSCLC patients who experienced progression after first- and second-generation TKI treatment and underwent testing for EGFR using plasma samples between January 2021 and April 2023 were enrolled. The T90M mutation rate and related clinical factors were evaluated. We utilized the Chi-square test or Fisher’s exact test for univariate analysis and multivariable logistic binary regression for multivariate analysis. Results: A total of 247 patients were eligible for the study. Patients harbored the exon 19 deletion mutation (Del19), exon 21 L858R point mutation, and uncommon mutations in 63.2%, 34.4%, and 2.4% of cases, respectively. The overall T790M mutation rate was 33.6%. In multivariate analyses, the Del19 mutation versus L858R mutation, duration of first-line TKI exceeding 12 months versus below 12 months, and solitary lesion progression versus multiple lesion progression were identified as favorable prognostic factors for the occurrence of T790M mutation. Conclusion: Patients with EGFR exon 19 deletion, a prolonged treatment duration of first-line EGFR-TKI, and solitary lesion progression pattern are more likely to acquire the T790M mutation, as detected by the PCR method in plasma samples.

Current status and breakthroughs in treating advanced non-small cell lung cancer with EGFR exon 20 insertion mutations

Recently, targeted therapy and immunotherapy have emerged as effective treatment options for non-small cell lung cancer (NSCLC). This progress has been facilitated by the rapid development of diagnostic and therapeutic technologies and the continuous research and development of new drugs, leading to a new era in precision medicine for NSCLC. This is a breakthrough for patients with common mutations in the human epidermal growth factor receptor (EGFR) gene in NSCLC. Consequently, the use of targeted drugs has significantly improved survival. Nevertheless, certain rare genetic mutations are referred to as EGFR exon 20 insertion (ex20ins) mutations, which differ in structure from conventional EGFR gene mutations, namely, exon 19 deletion mutations (19-Del) and exon 21 point mutations. Owing to their distinct structural characteristics, patients harboring these EGFR ex20ins mutations are unresponsive to traditional tyrosine kinase inhibitor (TKI) therapy. This particular group of patients did not fall within the scope of their applicability. However, the activating A763_Y764insFQEA mutation elicits a more pronounced response than mutations in the near and far regions of the C-helix immediately following it and should, therefore, be treated differently. Currently, there is a lack of effective treatments for EGFR ex20ins mutations NSCLC. The efficacy of chemotherapy has been relatively favorable, whereas the effectiveness of immunotherapy remains ambiguous owing to inadequate clinical data. In addition, the efficacy of the first- and second-generation targeted drugs remains limited. However, third-generation and novel targeted drugs have proven to be effective. Although novel EGFR-TKIs are expected to treat EGFR ex20ins mutations in patients with NSCLC, they face many challenges. The main focus of this review is on emerging therapies that target NSCLC with EGFR ex20ins and highlight major ongoing clinical trials while also providing an overview of the associated challenges and research advancements in this area.

Loss of copy numbers of retrotransposons (HERVK) on chromosome 7p11.2 impacts EGFR (Epidermal Growth Factor Receptor)-induced phenotypes for platinum sensitivity and long-term survival in ovarian cancer-A study from the OVCAD consortium.

We analyzed variations in the epidermal growth factor receptor (EGFR) gene and 5'-upstream region to identify potential molecular predictors of treatment response in primary epithelial ovarian cancer. Tumor tissues collected during debulking surgery from the prospective multicenter OVCAD study were investigated. Copy number variations in the human endogenous retrovirus sequence human endogenous retrovirus K9 (HERVK9) and EGFR Exons 7 and 9, as well as repeat length and loss of heterozygosity of polymorphic CA-SSR I and relative EGFR mRNA expression were determined quantitatively. At least one EGFR variation was observed in 94% of the patients. Among the 30 combinations of variations discovered, enhanced platinum sensitivity (n = 151) was found dominantly with HERVK9 haploidy and Exon 7 tetraploidy, overrepresented among patients with survival ≥120 months (24/29, p = .0212). EGFR overexpression (≥80 percentile) was significantly less likely in the responders (17% vs. 32%, p = .044). Multivariate Cox regression analysis, including age, FIGO stage, and grade, indicated that the patients' subgroup was prognostically significant for CA-SSR I repeat length <18 CA for both alleles (HR 0.276, 95% confidence interval 0.109-0.655, p = .001). Although EGFR variations occur in ovarian cancer, the mRNA levels remain low compared to other EGFR-mutated cancers. Notably, the inherited length of the CA-SSR I repeat, HERVK9 haploidy, and Exon 7 tetraploidy conferred three times higher odds ratio to survive for more than 10 years under therapy. This may add value in guiding therapies if determined during follow-up in circulating tumor cells or circulating tumor DNA and offers HERVK9 as a potential therapeutic target.

The association of EGFR amplification with aberrant exon 20 insertion report using the cobas EGFR Mutation Test v2.

Determining the exact type of epidermal growth factor receptor (EGFR) exon 20 insertion (ex20ins) mutation in lung cancer has become important. We found that not all ex20ins mutations reported by cobas EGFR test v2 could be validated by Sanger sequencing even using surgical specimens with high tumor contents. This study aimed to validate the ex20ins results reported by the cobas test and to determine whether there were clinicopathological factors associated with aberrant cobas ex20ins report. In total, 123 cobas-reported cases with ex20ins were retrospectively collected and validated by Sanger sequencing and Idylla assay. Clinicopathological features between ex20ins cobas+/Sanger+ group (n = 71) and cobas+/Sanger- group (n = 52) were compared. The Idylla assay detected ex20ins in 82.6% of cobas+/Sanger+ cases but only in 4.9% of cobas+/Sanger- cases. The cobas+/Sanger- group was significantly associated with higher tumor contents, poorly differentiated patterns, tumor necrosis, and a lower internal control cycle threshold value reported by the Idylla which suggesting the presence of increased EGFR gene copy numbers. EGFR fluorescence in situ hybridization (FISH) revealed the majority of cobas+/Sanger- group had EGFR high copy number gain (16%) or amplification (76%) according to the Colorado criteria. Among cases reported to have concomitant classic EGFR and ex20ins mutations by the cobas, the classic EGFR mutations were all detected by Sanger sequencing and Idylla, while the ex20ins mutations were undetected by Sanger sequencing (0%) or rarely reported by Idylla assay (3%). FISH revealed high EGFR copy number gain (17.9%) and amplification (79.5%) in cases reported having concomitant classic EGFR and ex20ins mutations by the cobas. This study demonstrated an unusually high frequency of EGFR amplification in cases with aberrant cobas ex20ins report which could not be validated by Sanger sequencing or Idylla assay. Ex20ins reported by the cobas test should be validated using other methods especially those reported having concomitant ex20ins and classic EGFR mutations.

A study of high dose furmonertinib in EGFR exon 20 insertion mutation-positive advanced non-small cell lung cancer.

The epidermal growth factor receptor (EGFR) ex20ins mutation, as a rare subtype of mutation, has gradually attracted attention. Its heterogeneity is high, its prognosis is extremely poor, and the efficacy of existing traditional treatment plans is limited. In this study, we aimed to evaluate efficacy of high dose furmonertinib as a first-line treatment for EGFR ex20ins-positive NSCLC. This is a retrospective, multi-center, non-interventional study. From May 2021 to March 2023, 9 NSCLC patients with EGFR ex20ins were enrolled. Efficacy and safety of 160 mg furmonertinib were evaluated. Objective response rate (ORR), disease control rate (DCR), median progression-free survival (PFS) and treatment related adverse events (TRAEs) were assessed. Of the evaluated patients, six patients experienced partial remission (PR), two patients experienced stable disease (SD) and one patient experienced progress disease (PD). Data indicated 66.7% ORR and 88.9% DCR. The median progression free survival (PFS) was 7.2 months (95% CI: 6.616 - 7.784). Besides, a longgest PFS with 18 months was found in one patient with p.H773_V774insGTNPH mutation. No ≥ level 3 adverse events have been found. The study proved the potential efficacy of 160mg furmonertinib in patients with advanced NSCLC with EGFR ex20ins. Meanwhile, 160mg furmonertinib had a good safety profile.

Abstract CT152: FURTHER: A global study to evaluate furmonertinib in patients with EGFR mutant NSCLC including uncommon EGFR mutations

Abstract Background: Furmonertinib (AST2818) is an oral, highly brain-penetrant, and broadly active mutation-selective epidermal growth factor receptor (EGFR) inhibitor engineered for broad activity and selectivity across EGFR mutations (mts) (Musib et al., NACLC 2022). Furmonertinib is approved in China for first-line advanced NSCLC with EGFR Ex19del or L858R mts based on the positive Phase 3 study (FURLONG) versus gefitinib. Furmonertinib has also demonstrated promising interim efficacy and safety in patients (pts) with NSCLC with EGFR exon 20 insertion (ex20ins) mts with a confirmed overall response rate (ORR) of 78.6% (n=28) by blinded independent central review (BICR) with a preliminary median duration of response (DoR) of 15.2 months in the front-line setting (FAVOUR study; see Han et al., WCLC 2023). Furmonertinib recently obtained FDA Breakthrough Therapy Designation for the treatment of pts with advanced NSCLC with EGFR ex20ins mts. P-loop and αC-helix Compressing (PACC) mts represent another subset of uncommon EGFR mts (Robichaux et al., 2021) that are similar to ex20ins mts in narrowing the drug-binding pocket; including G719X, S768I, E709X, L747X, V774M. Preclinical data indicating that furmonertinib is potent in models harboring EGFR PACC mts will be presented at this meeting (Nilsson et al., Abstract #4174). Developing efficacious, well-tolerated, and CNS-penetrant medicines for NSCLC pts with EGFR ex20ins mts and PACC mts remains an unmet need. Methods: FURTHER (FURMO-002) is the first global trial evaluating furmonertinib in NSCLC pts with EGFR and HER2 mts in North America, Europe, and the Asia-Pacific. FURTHER is a phase 1b, open-label, multicenter study in which pts will be treated orally with furmonertinib daily. For Stage 1 dose-escalation, the primary endpoint is incidence and severity of adverse events, including dose limiting toxicities and has been completed. For Stage 2 dose expansion, approximately 120 pts will be enrolled across 4 expansion cohorts. Stage 2 Cohorts 1-3 dose expansion cohorts will enroll pts with previously treated, locally advanced or metastatic NSCLC pts with either EGFR ex20ins mts, HER2 ex20ins mts, or EGFR activating mts, respectively. Cohorts 1-3 allow enrollment of pts with prior EGFR or HER2-directed therapy. Stage 2 Cohort 4 will enroll EGFR TKI-naïve NSCLC pts with EGFR PACC mts. Key inclusion criteria include documented EGFR or HER2 mts by local testing and measurable disease per RECIST v1.1. Stage 2 primary endpoint is ORR using RECIST v1.1. Key secondary endpoints include progression-free survival and overall survival. Stage 2 enrollment is ongoing. Clinical trial information: NCT05364073. Citation Format: Xiuning Le, Alexander Spira, Shirish Gadgeel, Yan Yu, Yanqiu Zhao, Ying Cheng, Jonathan Riess, Oscar Juan-Vidal, Bo Gao, Kiyotaka Yoh, Martin Forster, Satoru Kitazono, Hidetoshi Hayashi, David Planchard, Yong Jiang, Jack Huang, Nichole Baio, Marcin Kowanetz, Shirley Wang, William Leung, Jerry Y. Hsu, Jie Wang. FURTHER: A global study to evaluate furmonertinib in patients with EGFR mutant NSCLC including uncommon EGFR mutations [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr CT152.

Efficacy of targeted therapy in patients with non-small cell lung cancer harboring very rare mutations in EGFR exon 18.

Somatic mutations in epidermal growth factor receptor (EGFR) exon 18 are classified as uncommon or rare mutations in non-small cell lung cancer (NSCLC), in this context, other than G719X or E709X exon 18 mutations are even more rare and heterogeneous. In such scenario, first line treatment options are still debated. The aim of this study was to investigate the response of NSCLC patients harboring very rare exon 18 mutations to EGFR tyrosine kinase inhibitors (EGFR-TKIs). This retrospective descriptive study included 105 patients with NSCLC harboring mutations in EGFR exon 18 diagnosed at West China Hospital. The clinical response to EGFR-TKIs was evaluated according to different classifications of mutations in 45 NSCLC patients: 39 harboring G719X or E709X mutations and 6 harboring very rare mutations in EGFR exon 18. Among 105 patients, 84% (88/105) harbored rare mutations in EGFR exon 18, including G719X and E709X mutations. The remaining 16% (17/105) had very rare mutations in EGFR exon 18, including E709_710delinsX and G724S. For the subsequent efficacy analysis of EGFR-TKI in 45 NSCLC patients, patients harboring very rare mutations achieved a favorable disease control rate (DCR) of 100% and had a median progression-free survival (PFS) of 17.2 months, which was not significantly different compared to patients harboring G719X or E709X (P=0.59). EGFR-TKIs showed great efficacy in terms of responses and survival in patients harboring exon 18 EGFR rare mutations. This may justify the use of targeted therapies as a potential treatment strategy for these patients.

The Butterfly Flies - Practice Changing Results of PAPILLON, First Line Chemotherapy and Amivantamab for the Treatment of NSCLC Patients with EGFR Exon 20 Insertions.

Epidermal growth factor receptor (EGFR) exon 20 insertions are a rare subtype of EGFR mutations that do not respond to EGFR tyrosine kinase inhibitors developed for sensitizing mutations. In 2021, two drugs, amivantamab and mobocertinib each received FDA accelerated approval for second line use after platinum based therapy. These drugs were then brought to first line setting clinical trials; PAPILLON and EXCLAIM2. PAPILLON, which compared amivantamab plus chemotherapy to chemotherapy was positive, whereas EXCLAIM2, which compared mobocertinib to chemotherapy was negative. The PAPILLON regimen received subsequent FDA approval. In this commentary, we review the details of PAPILLON and also discuss why the rival trial, EXCLAIM2, may have failed.

Uncommon and Rare EGFR Mutations in Non-Small Cell Lung Cancer Patients with a Focus on Exon 20 Insertions and the Phase 3 PAPILLON Trial: The State of the Art.

Uncommon (ucEGFRmuts) and rare epidermal growth factor receptor (EGFR) mutations account for 10-15% of diagnosed cases and consist of a heterogeneous group represented by several clusters within exons 18-21 (e.g., exon 18 point mutations, exon 21 L861X, exon 20 S768I), as well as exon 20 insertions (Ex20ins). Their incidence is under molecular and clinical investigation following recent findings that reported an increase of sensitivity and specificity of next-generation sequencing (NGS) methods. Consequently, their detection allows for the selection of emerging treatment options to significantly improve patients' outcomes in these particular subgroups of EGFR-mutated advanced non-small cell lung cancer (NSCLC). Specifically, this commentary is focused on the notable progress of the Phase 3 PAPILLON study that showed primary efficacy results from amivantamab, a bispecific antibody with specific binding and affinity to extracellular domains of EGFR and MET, plus chemotherapy in the first-line setting for EGFR exon 20 insertion-mutated advanced or metastatic NSCLC patients, as compared with chemotherapy alone, thus becoming the new standard of care in this group of patients.

Effect of early dose reduction of osimertinib on efficacy in the first-line treatment for EGFR-mutated non-small cell lung cancer.

Osimertinib is used as the first-line therapy for patients with epidermal growth factor receptor (EGFR)-mutated non-small cell lung cancer (NSCLC). However, early dose reduction is often required due to adverse events (AEs). This study aimed to evaluate the effect of early dose reduction of osimertinib on efficacy and safety.This was a retrospective study including patients with EGFR-mutated NSCLC who were started on osimertinib as the first-line therapy between August 2018 and December 2021. Patients whose doses were reduced to less than 80mg/day within 6 months of osimertinib initiation or started at 40mg/day were defined as the dose reduction group. The primary endpoint was progression-free survival (PFS). Factors affecting PFS were explored using the Cox proportional hazards model.A total of 85 patients were included in this study. No significant differences in patient characteristics were observed between the dose reduction (n = 25) and standard dose groups (n = 60). The median PFS in the dose reduction group was significantly prolonged compared with that in the standard dose group (26.0 months vs. 12.0 months, p = 0.03). Multivariable analysis of 84 patients, excluding a patient with unknown brain metastasis, revealed that EGFR exon 21 L858R mutation, malignant pleural effusion or pleural metastasis, liver metastasis, and dose reduction within 6 months were independent factors affecting PFS.Early dose reduction of osimertinib is an effective therapeutic strategy for prolonging PFS in patients with EGFR-mutated NSCLC.

Abstract 3263: VEGFA mediates traditional EGFR-TKI resistance in non-small cell lung cancer with EGFR exon 20 insertions

Abstract Background: Epidermal growth factor receptor (EGFR) exon 20 insertions (Ex20ins) accounted for 4%-12% of EGFR mutations and showed primary resistance to EGFR tyrosine kinase inhibitors (EGFR-TKIs) which is an urgent issue to be solved. In our previous studies, we found that antiangiogenetic therapy had certain advantages for patients with Ex20ins in the real-world practice. Previous research showed the tumor microenvironment has been associated with resistance to targeted therapy in sensitive mutations. However, the mechanism of resistance of EGFR-TKIs and the advantage of antiangiogenetic therapy in patients with EGFR Ex20ins were still unclear. Methods: In this study, patients with EGFR exon 19 deletion (19del), exon 21 p.L858R (21L858R), and Ex20ins were collected to identify the efficacy of EGFR-TKIs. Stable cell lines expressing were established and used to compare signaling pathway activation. Matrigel angiogenesis assay was conducted in different cell lines. Next, we evaluated the efficacy of various treatments combined with antiangiogenetic agents or not in mouse models. Results: We collected 23 patients with EGFR sensitive mutations and Ex20ins, respectively, and found Ex20ins presented primary resistance to TKIs and poor survival outcomes. Based on the RNA sequence of stable cell lines, it was found that Ex20ins had a higher level of VEGFA expression and enriched in MAPK pathway compared to EGFR 19del and 21L858R. Immunohistochemical studies also revealed that a higher level of VEGFA expression was observed in a cohort of NSCLC patients with Ex20ins mutation compared with 19del or L858R. Matrigel angiogenesis assay has shown consistent result that Ex20ins promoted angiogenesis in vivo. Further experiments in mouse models identified that in the group of Osimertinib, mobocertinib alone, chemotherapy alone, mobocertinib or chemotherapy combination with bevacizumab, Osimertinib achieved the worst efficacy and additional utility of antiangiogenetic agents had a more favorable efficacy. Conclusion: Our study highlights the potential of VEGFA as a mechanism of resistance to EGFR-TKIs and induces immunosuppression microenvironment in NSCLC with Ex20ins. Furthermore, the findings suggested that antiangiogenetic therapy could be a promising therapeutic approach. Keywords: VEGFA, targeted therapy, resistance, EGFR exon 20 insertions, non-small cell lung cancer Citation Format: Yaning Yang, Chengming Liu, Guangjian Yang, Haiyan Xu, Siyu Lei, Yan Wang. VEGFA mediates traditional EGFR-TKI resistance in non-small cell lung cancer with EGFR exon 20 insertions [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3263.

Abstract 6504: Exploratory analysis using serial cell-free DNA in patients treated with amivantamab in non-small cell lung cancer with EGFR exon 20 insertion mutations

Abstract Introduction: Epidermal growth factor receptor (EGFR) exon 20 insertion (ex20 ins) mutation showed limited clinical activity with conventional EGFR tyrosine kinase inhibitors (TKIs). Amivantamab is the first bispecific antibody to be approved for the treatment of metastatic non-small cell lung cancer (NSCLC) with EGFR ex20ins mutation. However, limited data is available in terms of predictive biomarkers and the resistance mechanism. In this study, we conducted an exploratory analysis to elucidate a genomic landscape using circulating tumor DNA (ctDNA) from plasma samples. Patients and Methods: This study include result from 79 blood samples, which has been prospectively collected from 27 EGFR ex20ins mutated NSCLC patients (confirmed by either tissue or plasma-based test) who were treated with amivantamab. ctDNAs were obtained from plasma, which was serially collected at baseline, after 2 cycles of treatment, 2 cycles prior to the treatment discontinuation, and at the time point of disease progression. Guardant OMNI panel (Guardant Health, CA, USA) was used for the genomic profiling. Results: The median follow-up duration was 5.8 months (range 2.7-12.7). The overall response rate was 40.7% (95% confidence interval [CI] 24.5-59.2, n=11), and median progression-free survival was 5.8 months (95% CI 3.9-15.9) with a median duration of response of 9.8 months (95% CI, 7.3-NA). Patients with EGFR ex20ins not detected from ctDNA at baseline (n=10) showed significantly longer PFS compared to patients with EGFR ex20ins identified at baseline plasma sample (n=17) (14.6 vs 3.9 months; hazard ratio [HR] 0.40, 95% CI 0.17-0.95, P&amp;lt;0.05).The most common concurrent somatic variations at baseline were TP53 (62.9%), TERT (18.5%), ATM (18.5%). Longer median PFS was observed in patients without EGFR amplification (n=18) compared to patients with concurrent EGFR amplification (n=9) (11.1 vs. 2.5 months; HR 0.30, 95% CI 0.11-0.77, P &amp;lt;0.05). The presence of plasma EGFR ex20ins at C2D15 predicted poor PFS (17.8 vs 2.7 months; HR 0.17, 95% CI 0.06-0.47, P &amp;lt;0.01), regardless of baseline its presence or absence. Based on the paired analysis using baseline and at the timepoint of disease progression, putative resistance mechanism to amivantamab was identified in 14 patients (60.8%), which were PDGFRB (28.5%), followed by PTEN (21.4%), CHEK2 (21.4%). Conclusions: This study provides a comprehensive longitudinal ctDNA analysis in patients with EGFR ex20ins mutant NSCLC who were treated with amivantamab. Our results suggested that the presence of ctDNA for EGFR ex20ins mutation and co-alteration with EGFR amplification at baseline might be related to the clinical outcomes of amivantamab. Citation Format: Geun-Ho Park, Sehhoon Park, Hyen-Ae Jung, Jong-Mu Sun, Jin Seok Ahn, Myung-Ju Ahn, Se-Hoon Lee. Exploratory analysis using serial cell-free DNA in patients treated with amivantamab in non-small cell lung cancer with EGFR exon 20 insertion mutations [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6504.

Cost-effectiveness analysis of amivantamab plus chemotherapy versus chemotherapy alone in NSCLC with EGFR Exon 20 insertions.

Amivantamab plus chemotherapy has been proved to be an efficient treatment strategy for non-small-cell lung cancer (NSCLC) with epidermal growth factor receptor (EGFR) exon 20 insertions. The aim of this study was to conduct the cost-effectiveness analysis of amivantamab-chemotherapy compared with chemotherapy alone in NSCLC harboring EGFR exon 20 insertion mutations. We constructed a Markov model based on the data derived from the PAPILLON trial. We evaluated the cost, quality-adjusted life years (QALYs), and incremental cost-effectiveness ratio (ICER). One-way and probabilistic sensitivity analyses were used to evaluate the influence of different parameters on this model. Compared with chemotherapy alone, amivantamab combined with chemotherapy treatment gained an incremental effectiveness of 0.473 QALYs and an incremental cost of $361,950.952, which resulted in an ICER of $765,224/QALY. The ICER was much higher than the willingness-to-pay threshold of 15,0000/QALY. One-way sensitivity analysis revealed that amivantamab cost was the leading influential factor in the model. Compared with chemotherapy alone, amivantamab plus chemotherapy is not a cost-effective first-line treatment choice for NSCLC patients with EGFR exon 20 insertions. The costly price of amivantamab is one of the major reasons for the high cost of this combined treatment strategy. Therefore, it is imperative to take into account the high cost of amivantamab in the subsequent clinical application and strive to attain a relative equilibrium between its significant clinical benefit and economic encumbrance.

Abstract 3711: Procedure establishment of EGFR mutation test with circulating tumor cells of lung cancer by in vitro assay

Abstract Introduction: Non-small cell lung cancer (NSCLC) is the most common subtype, accounting for approximately 80% of lung cancer. The treatment for NSCLC has significantly improved since the introduction of targeted therapies. Epidermal growth factor receptor (EGFR) mutations are the most frequently found genetic alterations in NSCLC, and deletion of exon 19 is a representative example. Searching for this mutation may provide important clues to the use of EGFR tyrosine kinase inhibitors in NSCLC. So, the detection of EGFR mutation is important step in cancer diagnosis and determining the drug treatment strategy, but the detection of mutation with tissues has limitations such as clinical challenge to poorly accessible tumor tissues before and after treatment. The aim of this study was to explore the feasibility and utility of implementation of EGFR molecular testing from circulating tumor cells (CTC) in NSCLC. Here, we developed and optimized the procedure of mutated EGFR detection in CTC after isolation with CytoGen’s Smart BiopsyTM CTC isolator by cobas® EGFR Mutation Test. This EGFR mutation test in CTC showed the potential to overcome the limitations of tissue biopsy with high sensitivity and specificity in an in vitro assay. Method: PC-9 cells were used the positive control of EGFR mutation (EGFR exon 19 deletion). Limit of detection (LOD) was performed with PC-9 cells (200 cells to 5 cells, 6 points) spiked into blood sample (5mL, healthy donor) to mimic CTC in the blood of lung cancer patient. CTC were isolated from spiked samples using CytoGen’s Smart BiopsyTM CTC isolator, subsequently cobas® EGFR Mutation Test was carried out to detect of EGFR mutation. Results: In in vitro experiments of recovery test using cell lines spiked into blood from healthy donor, the recovery rate of CytoGen’s Smart Biopsy TM CTC isolator showed over 80%. As a result of LOD test, EGFR exon19 deletion mutation of PC-9 cells was clearly detected even in the smallest number of cells were spiked into blood (5 cells in 5mL blood) and was not detected at all in the negative controls. The result suggested that CytoGen’s Smart Biopsy TM CTC isolator can isolate CTC with high recovery rate and apply the test of oncogenic mutations including EGFR mutation in CTC. Conclusions: Confirmation of EGFR mutation is important step in the diagnosis and selection of optimal drug for cancer patients. However, tissue biopsy has several limitations such as difficulties to get tissue samples and inaccurate information due to invasive method and tumor heterogeneity. Detection of EGFR mutation in CTC might overcome and make up for limitations of tissue biopsy. In this study, we optimized the EGFR mutation detection procedure of intact live CTC isolated by CytoGen’s Smart BiopsyTM CTC isolator. Citation Format: Jihyun Lee, Hoin Kang, Min Hyung Kim, Jubi Lee, Hyoyong Kim, Soee Kim, Hae Ung Lee, Hai-Chon Lee, Jung Won Kim. Procedure establishment of EGFR mutation test with circulating tumor cells of lung cancer by in vitro assay [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3711.

Abstract 5840: Identifying drug tolerant persister to neoadjuvant osimertinib in resectable non-small cell lung cancer harbouring EGFR mutations (NORA) via single-cell RNA sequencing

Abstract Introduction: Adjuvant osimertinib is the standard of care for resected, stage IB-IIIA non-small cell lung cancer (NSCLC) harboring activating epidermal growth factor receptor (EGFR) mutation. Yet, the role of neoadjuvant osimertinib is not clear. In the NORA trial (NCT04816838), we aimed to identify the drug tolerant persister (DTP) after neoadjuvant osimertinib for surgically resectable, EGFR-mutated stage IA-IIIA NSCLC. Methods: Patients harboring EGFR Exon 19 deletion or L858R at clinical stage IA-IIIA were given 80 mg of neoadjuvant osimertinib daily for two 28-day cycles followed by surgical resection and adjuvant osimertinib for 3 years. The key exploratory endpoint was to characterize the DTP via single-cell RNA sequencing (scRNA-seq) with pre and post-osimertinib samples. Results: We performed scRNA-seq on twenty-five patients enrolled at Yonsei Cancer Center from June 2021 to March 2022. Patients with stage IA (n=8, 32%), IB (n=7, 28%), IIA (n=4, 16%), IIB (n=4, 16%), and IIIA (n=2, 8%) were included. For EGFR mutation, exon 19 del and L858R accounted for 10 (40%) patients and 15 (60%) patients, respectively. The ORR (all partial response) was 44% (n=11), major pathologic response (MPR) rate was 24% (n=6), and pathologic complete response rate was 0%. ScRNA-seq revealed a total of 252,339 cells (60 clusters) annotated as epithelial cells (10 clusters), fibroblasts (7 clusters), immune cells (17 clusters), myeloid (15 clusters), endothelial cells (11 clusters) that showed distinct enrichment in post-osimertinib samples, non-MPR, and L858R subset. We found that a distint epithelial subset, namely EP8-AGER, identified as alveolar type 1 (AT1) cells was enriched in the non-MPR subset showing activation of Wnt, Hippo, and YAP/TAZ pathway. Pseudotemporal ordering of this cluster showed activation of signaling pathway for COL4A2/COL4A3 related to structural consistuent of extracellular matrix, and RTKN2 associated with NF-κB. In the fibroblast subset, the proportion of FB6-CD74 associated with chemokine activity and NF-κB was higher in the non-MPR and L858R group. In the myeloid subset, CD8-C1-GZMK identified as CD8+ T cells with activation/effector and cytotoxic signatures was also enriched in the post-osimertinib samples. Among macrophages, 3 clusters (annotated as SELENOP+, SPP1+, PLXDC2+) showed enrichment of cholesterol metabolism with activation of apolipoprotein E that promotes conversion of proinflammatory macrophages into anti-inflammatory phenotypes. Lastly, the proportion of EC9-LYZ, annotated as scavenging endothelial cells was higher in the non-MPR and L858R group. Conclusion: Neoadjuvant osimertinib resulted in the cellular reprogramming in the tumor microenvironment, notably AT1 epithelial cell which may lead to a loop between cancer cells and fibroblasts for the generation of DTP cells. Citation Format: Jii Bum (Joy) Lee, Su-Jin Choi, Young Joon Park, Kyoung-Ho Park, Seung Hyun Yong, Hyo Sup Shim, Byung Jo Park, Chang Young Lee, Min Hee Hong, Byoung Chul Cho, Sun Min Lim. Identifying drug tolerant persister to neoadjuvant osimertinib in resectable non-small cell lung cancer harbouring EGFR mutations (NORA) via single-cell RNA sequencing [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5840.

First-in-human phase I study of BEBT-109 in previously treated EGFR exon 20 insertion-mutated advanced non-small cell lung cancer

BEBT-109 is an oral pan-mutant-selective inhibitor of epidermal growth factor receptor (EGFR) that demonstrated promising antitumor potency in preclinical models. This first-in-human study was a single-arm, open-label, two-stage study. Phase Ia dose-escalation study evaluated the safety and pharmacokinetics of BEBT-109 in 11 patients with EGFR T790M-mutated advanced non-small cell lung cancer (aNSCLC). Phase Ib dose-expansion study evaluated the safety and efficacy of BEBT-109 in 18 patients with EGFR exon 20 insertion (ex20ins)-mutated treatment-refractory aNSCLC. The primary outcomes were adverse events and antitumor activity. Clinical trial registration number CTR20192575. The phase Ia study demonstrated no dose-limiting toxicity, no observation of the maximum tolerated dose, and no new safety signals with BEBT-109 in the dose range of 20-180mg/d, suggesting that BEBT-109 had an acceptable safety profile among patients with EGFR T790M-mutated aNSCLC. Plasma pharmacokinetics of BEBT-109 showed a dose-proportional increase in the area under the curve and maximal concentration, with no significant drug accumulation. The dose-expansion study demonstrated that BEBT-109 treatment was tolerable across the three dose levels. The three most common treatment-related adverse events were diarrhea (100%; 22.2% ≥Grade 3), rash (66.7%; 5.6% ≥Grade 3), and anemia (61.1%; 0% ≥Grade 3). The objective response rate was 44.4% (8 of 18). Median progression-free survival was 8.0months (95% confidence intervals, 1.33-14.67). Preliminary findings showed that BEBT-109 had an acceptable safety profile and favorable antitumor activity in patients with refractory EGFR ex20ins-mutated aNSCLC. National Natural Science Foundation of China.

Abstract 964: Updated results of a prospective observational multicenter study on resistance mechanisms to osimertinib using circulating tumor DNA analyses in EGFR-mutated non-small cell lung cancer patients (ELUCIDATOR study)

Abstract Background: Although osimertinib (Osi) is the key standard therapy for patients (pts) with advanced non-small cell lung cancer (NSCLC) harboring sensitizing epidermal growth factor receptor (EGFR) mutations, most of cases experience the progressive disease (PD) after initial response to the treatment. Therefore, understanding the Osi resistance mechanisms and identifying the poor responders are essential to develop better treatment strategies. Thus, we conducted a prospective observational multicenter study and analyzed serially collected circulating tumor DNA (ctDNA). Here we report the results from updated analyses focusing on the association between genetic information from ctDNA and clinical outcome. Methods: Patient eligibility criteria were as follows: a definitive diagnosis of non-squamous NSCLC confirmed through biopsy or cytology, EGFR exon 19 deletion (19del) or L858R mutation, Osi planned as first-line treatment, and pts who could provide blood specimens. Paired plasma DNA samples were collected before starting Osi as baseline (BL) and at PD and analyzed to investigate Osi resistance by next-generation sequencing (NGS). Correlations between genetic information obtained from ctDNA and clinical outcome such as progression free survival (PFS) and overall survival (OS) were evaluated. The median follow-up time was 33.1 months. Results: One hundred eighty-eight pts were enrolled between May 2019 and January 2021, and 125 (66%) were female, 96 (51%) were EGFR 19del mutation, and 109 (58%) were never smoker. Among those, 178 pts were included in the analyses, and 111 experienced PD. In consistent with previous reports, median PFS (mPFS) and median OS (mOS) were 19.1 months and 36.0 months, respectively. The efficacy of Osi differed between 19del and L858R in both PFS and OS, with 19del being longer outcome [mPFS, 23.3 months vs. 17.2 months, HR: 1.56 (95%CI: 1.08-2.26), mOS, 40.3 months vs. 30.4 months, HR: 1.54 (95%CI: 0.98-2.45)]. Univariate analysis revealed that the presence of TP53 mutations and MET amplification (amp) at BL was a predictive factor of shorter PFS and OS. Multivariate analysis also revealed that the TP53 mutations at BL was a predictive factor of shorter PFS and OS. Plasma samples from 85 pts were available for ctDNA analysis. New adaptive mutations or amp at PD were detected in genes such as PIK3CA in 3 cases, MET amp in 4, TP53 in 4, BRIMP3 in 2, APC in 1, and BRAF in 2. Secondary EGFR C797S resistance mutation was detected in 1 case. Conclusions: TP53 mutation at BL could be predictive of poor response to Osi. MET amp and PIK3CA mutations were detected as the most common resistance mechanisms, and secondary EGFR resistance mutations were observed less frequently than previous reports. Citation Format: Mitsuo Osuga, Akihiro Tamiya, Daijiro Harada, Yasuyuki Mizumori, Shun-ichi Isa, Yoshihiko Taniguchi, Keiichi Nakamura, Tsutomu Shinohara, Hidetoshi Yanai, Katsumi Nakatomi, Masahide Oki, Masahide Mori, Tomohito Kuwako, Koji Yamazaki, Atsuhisa Tamura, Masahiko Ando, Yasuhiro Koh. Updated results of a prospective observational multicenter study on resistance mechanisms to osimertinib using circulating tumor DNA analyses in EGFR-mutated non-small cell lung cancer patients (ELUCIDATOR study) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 964.

[First-line Treatment with Furmonertinib Mesylate in Lung Adenocarcinoma Patient 
with EGFR Exon 20 Insertion Mutantion].

With the continuous innovation of genomics, proteomics and molecular biological detection technology, the treatment of non-small cell lung cancer (NSCLC) has changed from traditional chemotherapy to immunotherapy and targeted therapy. Among them, molecular tumor markers targeting tyrosine kinase pathways play more important roles in clinical practice. For advanced NSCLC patients with positive epidermal growth factor receptor (EGFR) mutations, there are many first-line drugs on the market and they could bring significant efficacy, thus completely subverting the treatment pattern of advanced NSCLC. Common mutations of EGFR in Chinese patients are located on exons 19, 20 and 21, of which exons 19 and 21 mutations are the more common types. Besides, there is also a subtype of EGFR mutations, known as EGFR 20 exon insertion (EGFR 20ins) mutation. The authors summarized the treatment of a lung adenocarcinoma patient with EGFR 20ins mutation accepting Furmonertinib mesylate, in order to provide effective references for clinical diagnosis and treatment.
.

EGFR exon 18 delE709_T710insD mutated stage IV non-small cell lung cancer treated with osimertinib: a case report.

Mutations in tyrosine kinase domain of epidermal growth factor receptor (EGFR) are observed in approximately 15% of non-small cell lung cancer adenocarcinoma. Exon 19 deletions or exon 21 L858R mutations are predominant in frequency and show high sensitivity to EGFR tyrosine kinase inhibitors (TKIs). Exon 18 mutations are extremely rare and the delE709_T710insD mutation accounts for only 0.16% of mutations when occurring as a sole mutation. This specific mutation in exon 18 seems to respond to certain EGFR TKIs such as afatinib. However, given the rarity of this mutation, determining the most effective TKI for its treatment remains unclear. We report a 70-year-old woman diagnosed with stage IV-A lung adenocarcinoma harboring EGFR delE709_T710insD mutation treated in first-line with Osimertinib using standard schedule and doses experiencing renal toxicity and disease progression after 9 weeks of treatment.

Delayed cardiotoxicity following osimertinib therapy in non-small cell lung cancer: a unique case report.

This case report features a 62-year-old male with stage IB lung adenocarcinoma harboring an epidermal growth factor receptor exon 19 deletion, who underwent treatment with osimertinib following a left upper lobectomy and lymph node dissection. Despite a history of smoking and well-managed type 2 diabetes, the patient developed heart failure 18 months post-initiation of osimertinib therapy, marking one of the latest occurrences of heart failure following osimertinib treatment documented in limited literature. Cardiac MRI revealed significant left ventricular enlargement, lateral wall myocardial thinning, and localized myocardial fibrosis without perfusion defects, a finding not previously reported in literature. This case underscores the severe and unusual cardiac effects of osimertinib in patients with latent risk factors, highlighting the importance of vigilant cardiac monitoring and a multidisciplinary management approach.