Rare Epidermal Growth Factor Receptor Research Articles

Value of peripheral blood rare cell EGFR gene amplification detection in the evaluation of benign and malignant pulmonary nodules

Objective: To explore the value of detection of epidermal growth factor receptor (EGFR) gene amplification in peripheral blood rare cells in the assessment of benign and malignant pulmonary nodules. Methods: A total of 262 patients with pulmonary nodules were selected as the retrospectively study subjects from the Second Affiliated Hospital of Army Military Medical University and Peking Union Medical College Hospital from July 2022 to August 2023. There were 98 males and 164 females, with the age range from 16 to 79 (52.1±12.1) years. The EGFR gene amplification testing was performed on the rare cells enriched from patients' peripheral blood, and the clinical manifestations, CT imaging features, histopathological and/or pathological cytological confirmed results of patients were collected. The receiver operating characteristic (ROC) curve was used to determine the optimal cut-off value of the method of detection of EGFR gene amplification in peripheral blood rare cells, and its diagnostic efficacy was evaluated. Results: Among the 262 patients, 143 were malignant pulmonary nodules and 119 were benign pulmonary nodules. The differences between malignant pulmonary nodules and benign pulmonary nodules in nodule diameter and nodule density were statistically significant (both P<0.001), while the differences in age, gender and nodule number were not statistically significant (all P>0.05). The number [M (Q1, Q3)] of EGFR gene amplification positive rare cells in patients with malignant pulmonary nodule was 8 (6, 11), which was higher than that in patients with benign pulmonary nodule [2 (1, 4), P<0.001]. The ROC curve results showed that when the optimal cut-off value was 5 (that was, the number of EGFR gene amplification positive rare cells was>5), the area under the curve (AUC) of the detection of EGFR gene amplification in peripheral blood rare cells for discrimination of benign and malignant pulmonary lesions was 0.816 (95%CI: 0.761-0.870), with a sensitivity of 83.2%, a specificity of 80.7%, and an accuracy of 82.1%. Based on the analysis of the diameter of the nodules, the AUC for distinguishing between benign and malignant pulmonary nodules with diameter 5-9 mm and 10-30 mm was 0.797 (95%CI: 0.707-0.887) and 0.809 (95%CI: 0.669-0.949), respectively, with sensitivity, specificity and accuracy reached 75% or above. Based on the analysis of nodule density, the AUC for distinguishing between benign and malignant solid nodule and subsolid nodule was 0.845 (95%CI: 0.751-0.939) and 0.790 (95%CI: 0.701-0.880), respectively, with sensitivity, specificity and accuracy reached 75% or above. Based on the analysis of nodule number, the AUC for distinguishing between benign and malignant solitary pulmonary nodule and multiple pulmonary nodule was 0.830 (95%CI: 0.696-0.965) and 0.817 (95%CI: 0.758-0.877), respectively, with sensitivity, specificity and accuracy reached 80% or above. Conclusion: The detection of EGFR gene amplification in peripheral blood rare cells contributes to the evaluation of benign and malignant pulmonary nodules, and can be used in the auxiliary diagnosis of benign and malignant pulmonary nodules.

The effect of food on the pharmacokinetics of Sutetinib maleate capsule, an irreversible EGFR tyrosine kinase inhibitor, in healthy Chinese subjects.

Sutetinib is an irreversible inhibitor of epidermal growth factor receptor (EGFR) and showed favorable efficacy and safety in patients with locally advanced or metastatic non-small cell lung cancer (NSCLC) harbouring nondrug-resistant rare EGFR mutations. To evaluate the potential food effect, eighteen healthy Chinese subjects were enrolled in a single-centre, randomized, open-label, two-sequence, two-period crossover study. Sutetinib was administered as a single oral 100mg under fasting or fed conditions, and pharmacokinetic sampling was performed following each dose and analysed by a validated liquid chromatography/mass spectrometry method. Safety and tolerability were also evaluated. Food intake slightly decreased maximum plasma concentration (Cmax) and area under the plasma concentration-time curve from time 0 to infinity (AUC0 - inf) of sutetinib (geometric least-squares mean [GLSM] ratio, 80.94% and 86.11%; 90% confidence interval [CI], 68.43-95.72 and 75.88-97.73) and its active metabolite sutetinib N-Oxide (GLSM ratio, 75.58% and 84.00%; 90% CI, 65.69-86.95 and 75.42-93.56), respectively. In addition, the time to maximum plasma concentration (Tmax) of both sutetinib and its metabolite has been prolonged by 2h under fed conditions. A total of 31 adverse events (AEs) occurred during the study, with no serious adverse events (SAE) reported, and no obvious difference was observed between the fasting and fed groups. Our results demonstrated that a high-fat and high-calorie diet caused a significant delay in drug absorption and a marginal reduction in drug exposure. Sutetinib was generally well tolerated in healthy Chinese subjects. (This trial was registered at http://www.chinadrugtrials.org.cn . The registration No. is CTR20201933, and the date of registration is 2020-10-16).

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.

An epidermal growth factor receptor compound mutation of L858R with S768I in advanced non-small-cell lung cancer: a case report

BackgroundIn the current treatment landscape for non-small cell lung cancers, epidermal growth factor receptor-tyrosine kinase inhibitors have emerged as a well-established treatment option for patients with advanced or metastatic disease. This is particularly true for those with commonly occurring epidermal growth factor receptor mutations. However, the therapeutic efficacy of these agents for so-called rare epidermal growth factor receptor mutations, and in particular those characterized by a high degree of complexity, such as double mutations, remains a subject of clinical uncertainty.Case presentationIn this context, we present the case of a 64-year-old man of Moroccan descent, a lifelong non-smoker, diagnosed with metastatic non-small cell lung cancer characterized by a complex epidermal growth factor receptor mutation encompassing L858R and S768I. The patient subsequently underwent afatinib-based treatment, showing notable clinical results. These included a remarkable overall survival of 51 months, with a median progression-free survival of more than 39 months.ConclusionsThis case report is a compelling testimony to the evolving therapeutic landscape of non-small cell lung cancers, providing valuable insight into the potential therapeutic efficacy of epidermal growth factor receptor-tyrosine kinase inhibitors in the realm of rare and complex epidermal growth factor receptor mutations.

Clinical utility of the Oncomine Dx Target Test multi-CDx system and the possibility of utilizing those original sequence data.

Companion diagnostic tests play a crucial role in guiding treatment decisions for patients with non-small cell lung cancer (NSCLC). The Oncomine Dx Target Test (ODxTT) Multi-CDx System has emerged as a prominent companion diagnostic method. However, its efficacy in detecting driver gene mutations, particularly rare mutations, warrants investigation. This study aimed to assess the performance of the ODxTT in detecting driver gene mutations in NSCLC patients. Specifically, we aimed to evaluate its sensitivity in detecting epidermal growth factor receptor (EGFR) mutations, a key determinant of treatment selection in NSCLC. We conducted a retrospective analysis of NSCLC patients who underwent testing with the ODxTT at Keio University Hospital between May 2020 and March 2022. Patient samples were subjected to both DNA and RNA tests. Driver gene mutation status was assessed, and instances of missed mutations were meticulously examined. Of the 90 patients, five had nucleic acid quality problems, while 85 underwent both DNA and RNA tests. Driver gene mutations were detected in 56/90 (62.2%) patients. Of the 34 patient specimens, driver mutations were not detected using the ODxTT; however, epidermal growth factor receptor (EGFR) mutations were detected using polymerase chain reaction-based testing in two patients, and a KRAS mutation was detected by careful examination of the sequence data obtained using the ODxTT in one patient. For the above three cases, carefully examining the gene sequence information obtained using the ODxTT could identify driver mutations that were not mentioned in the returned test results. Additionally, we confirmed comparable instances of overlook results for EGFR mutations in the dataset from South Korea, implying that this type of oversight could occur in other countries using the ODxTT. EGFR mutation was missed in ODxTT in Japan (6.3%, 2/32), South Korea (2.0%, 1/49), and overall (3.7%, 3/81). Even if sufficient tumor samples are obtained, rare EGFR mutations (which are excluded from the ODxTT's genetic mutation list) might not be detected using the current ODxTT system due to the program used for sequence analysis. However, such rare EGFR mutations can still be accurately detected on ODxTT's sequence data using next-generation sequencing.

Mutation Analysis of Epidermal Growth Factor Receptor Gene in Non-Small Cell Lung Cancer for Selection of Patients Eligible for Tyrosine Kinase Inhibitor Therapy

Introduction: Epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitor therapy is effective as a first-line treatment of advanced non-small-cell lung cancer (NSCLC). This research study investigated the distribution of EGFR mutations in patients diagnosed with NSCLC to assist in selecting patients who could benefit from tyrosine kinase inhibitor therapy. Materials and Methods: This cross-sectional study was conducted between July 2017 and November 2022. A real-time multiplex ​Polymerase Chain Reaction (PCR) assay supplied by Roche Diagnostics was used to examine DNA obtained from 682 tumor biopsies collected from NSCLC patients. DNA amplification was performed in a Cobas z 480 instrument for mutation analysis. The PCR assay was designed using specific primers and probes to detect 43 different mutations targeting exons 18-21. Results: Among the 682 samples, 466 (68.3%) were males, and 216 were females. The male-to-female ratio was 2.1. Twenty per cent of the male and 37% of the female samples were positive for EGFR mutations. The most common mutations were the in-frame deletion of exon 19, followed by L858R in exon 21, exon 20 insertion and S769I, exon 18 G719X. In addition, three mutations, namely del exon 19, T790M and exon 20 insertions were also detected in a patient, suggesting an actively progressive disease. Conclusions: This study showed that EGFR mutations are more common in Pakistani female patients than males. Secondly, in-frame deletion of exon 19 and exon 21 mutation L858R are prevalent in most of the NSCLC patients. The prevalence of common and rare EGFR mutations in Pakistani patients provides an opportunity for a subset of patients' chance of therapy.

Overview on Therapeutic Options in Uncommon EGFR Mutant Non-Small Cell Lung Cancer (NSCLC): New Lights for an Unmet Medical Need.

The majority of epidermal growth factor receptor (EGFR) mutations (85-90%) are exon 19 deletions and L858R point mutations of exon 21, characterized by high sensitivity to EGFR-tyrosine kinase inhibitors (TKIs). Less is known about uncommon mutations (10-15% of EGFR mutations). The predominant mutation types in this category include exon 18 point mutations, exon 21 L861X, exon 20 insertions, and exon 20 S768I. This group shows a heterogeneous prevalence, partly due to different testing methods and to the presence of compound mutations, which in some cases can lead to shorter overall survival and different sensitivity to different TKIs compared to simple mutations. Additionally, EGFR-TKI sensitivity may also vary depending on the specific mutation and the tertiary structure of the protein. The best strategy remains uncertain, and the data of EGFR-TKIs efficacy are based on few prospective and some retrospective series. Newer investigational agents are still under study, and there are no other approved specific treatments targeting uncommon EGFR mutations. Defining the best treatment option for this patient population remains an unmet medical need. The objective of this review is to evaluate existing data on the outcomes, epidemiology, and clinical characteristics of lung cancer patients with rare EGFR mutations, with a focus on intracranial activity and response to immunotherapy.

Rare mutation-dominant compound EGFR-positive NSCLC is associated with enriched kinase domain-resided variants of uncertain significance and poor clinical outcomes

BackgroundCompound epidermal growth factor receptor (EGFR) mutations are less responsive to tyrosine kinase inhibitors (TKIs) than single EGFR mutations in non-small cell lung cancer (NSCLC). However, the detailed clinical characteristics and prognosis of various compound EGFR mutations remain to be elucidated.MethodsWe retrospectively studied the next-generation sequencing (NGS) data of treatment-naïve tumors from 1025 NSCLC patients with compound EGFR mutations, which were sub-categorized into different combinations of common mutations (19-Del and EGFR exon 21 p.L858R), rare mutations, and variants of uncertain significance (VUSs). Prognosis and drug resistance to first-line TKIs were analyzed in 174 and 95 patients, respectively.ResultsCompound EGFR mutations were enriched with EGFR exon 21 p.L858R and rare mutations, but not 19-Del (P < 0.001). The common + rare and rare + rare subtypes had fewer concurrent mutations in the PI3K pathway (P = 0.032), while the rare + rare and common + VUSs subtypes showed increased association with smoking- and temozolomide-related mutational signatures, respectively (P < 0.001). The rare mutation-dominant subtypes (rare + VUSs and rare + rare) had the worst clinical outcomes to first-line TKIs (P < 0.001), which was further confirmed using an external cohort (P = 0.0066). VUSs in the rare + VUSs subtype selectively reside in the EGFR kinase domain (P < 0.001), implying these tumors might select additional mutations to disrupt the regulation/function of the kinase domain.ConclusionsDifferent subtypes of compound EGFR mutations displayed distinct clinical features and genetic architectures, and rare mutation-dominant compound EGFR mutations were associated with enriched kinase domain-resided VUSs and poor clinical outcomes. Our findings help better understand the oncogenesis of compound EGFR mutations and forecast prognostic outcomes of personalized treatments.

Six first-line tyrosine kinase inhibitors reveal novel inhibition potential for the EGFR S768I mutation

Lung cancer, the leading cause of cancer-related mortality, is the most commonly diagnosed cancer. Tyrosine kinase inhibitors (TKIs) are considered a drug-targeted therapy for non-small cell lung cancers (NSCLCs) with epidermal growth factor receptor (EGFR) mutations. However, limited data are available involving the activity of EGFR TKIs against rare EGFR mutations. Here, based on an endogenous EGFR-depleted cell Line H3255 by CRISPR, H3255 cells with rare mutant EGFRS768I and compound mutations EGFRS768I+L858R were tested using cell proliferation assay, cytotoxicity, membrane potential, flow cytometry and Western blot analysis. We conducted cytotoxicity screening of EGFR mutations on six front-line TKIs based on first-, second-, and third-generation TKIs (afatinib, dacomitinib, osimertinib, erlotinib, gefitinib, and icotinib). The results showed that the sensitivity of these mutants containing rare variants EGFRS768I to six front-line TKIs was enriched in the irreversible TKI cytotoxicity assays by determining their change in cytotoxicity, apoptosis, cell proliferation and signal pathway factors. Importantly, the variants harboring EGFRL858R (H3255), EGFRS768I (H3255S768I) and EGFRS768I+L858R (H3255S768I+L858R) were sensitive to six TKIs and induced cytotoxicity through different pathways. Moreover, the compound mutations EGFRS768I+L858R showed more TKI resistance than EGFRS768I mutation and EGFRL858R mutation. We present a comprehensive reference for the sensitivity of EGFRS768I variants to six front-line TKIs. For patients with the EGFR S768I mutation and compound mutations EGFRS768I+L858R, six first-line TKIs appear to be reasonable therapeutic options.

Defining the sensitivity landscape of EGFR variants to tyrosine kinase inhibitors

Tyrosine kinase inhibitor (TKI) is a standard treatment for patients with NSCLC harboring constitutively active epidermal growth factor receptor (EGFR) mutations. However, most rare EGFR mutations lack treatment regimens except for the well-studied ones. We constructed two EGFR variant libraries containing substitutions, deletions, or insertions using the saturation mutagenesis method. All the variants were located in the EGFR mutation hotspot (exons 18–21). The sensitivity of these variants to afatinib, erlotinib, gefitinib, icotinib, and osimertinib was systematically studied by determining their enrichment in massively parallel cytotoxicity assays using an endogenous EGFR-depleted cell line. A total of 3914 and 70,475 variants were detected in the constructed EGFR Substitution-Deletion (Sub-Del) and exon 20 Insertion (Ins) libraries. Of the 3914 Sub-Del variants, 221 proliferated fast in the control assay and were sensitive to EGFR-TKIs. For the 70,475 Ins variants, insertions at amino acid positions 770–774 were highly enriched in all 5 TKI cytotoxicity assays. Moreover, the top 5% of the enriched insertion variants included a glycine or serine insertion at high frequency. We present a comprehensive reference for the sensitivity of EGFR variants to five commonly used TKIs. The approach used here should be applicable to other genes and targeted drugs.

Detection of EGFR gene with a droplet digital PCR chip integrating a double-layer glass reservoir

The lack of reliable and practical method for detecting rare hot mutation of epidermal growth factor receptor (EGFR) in circulating tumor DNA (ctDNA) for lung cancer has remained a challenge for general clinical application due to excess wild type DNA in clinical samples. In this study, we developed a droplet digital PCR (ddPCR) platform, integrating a PDMS chip and double-layer glass reservoir. The duplex T-junction droplet generators in PDMS chip can produce about one million uniform droplets of 4.187 pL within ∼10 min, which were then stored in the glass reservoir. The double-layer glass reservoir can protect droplets from evaporation and breaking, solving the problem of instability during thermal-cycling. The quantitative capabilities of the ddPCR chip were evaluated by testing EGFR exon gene 21, with a good linear correlation in the wide range of 101 to 106 copies/μL (R2 = 0.9998). We then demonstrated that the proposed ddPCR device can recognize rare EGFR L858R mutation under a background of 106 copies/μL wild-type DNA at a sensitivity of 0.0001%. Finally, we demonstrated this ddPCR platform could identify low amount of EGFR L858R mutation in ctDNA and CTCs of patients with lung cancer.

Rare EGFR E709-T710delinsX: Molecular characteristics and superior response to afatinib treatment in NSCLC patients

ObjectivesCurrently, whether patients with rare epidermal growth factor receptor (EGFR) mutations could benefit from EGFR tyrosine kinase inhibitors (TKIs) demands further studies. Limited clinical data are available regarding the molecular characteristics and clinical response in non-small-cell lung cancer (NSCLC) patients harboring EGFR E709-T710delinsX mutations, a rare mutation type in exon 18 of EGFR. In this study, we aimed to explore the molecular distribution and clinical outcome of EGFR E709-T710delinsX mutated Chinese patients. MethodsNext-generation sequencing (NGS) tests were performed in 15,078 NSCLC patients. A multicenter retrospective cohort involving 17 advanced lung cancer patients with EGFR E709-T710delinsX was collected to evaluate clinical responses to diverse therapies. In silico protein structure modeling was conducted to predict drug response. Results5905 EGFR mutant patients (39.2%, 5905/15078) were identified, with 26 cases (0.44%, 26/5905) harbored EGFR E709-T710delinsD. Afatinib showed a better overall objective response rate (ORR) compared with the first-generation (1G) EGFR TKIs and chemotherapy with significant difference. Superior progression free survival (PFS) was also observed in patients treated with afatinib (afatinib 10.85 m vs 1G EGFR TKIs 4.0 m vs chemotherapy 2.8 m, p = 0.0007). In silico protein structure modeling predicts better binding of afatinib with EGFR E709-T710delinsD compared with other EGFR TKIs. ConclusionsThis is the largest studies for EGFR E709-T710delinsX, with 26 cases with EGFR E709-T710delinsX being identified (0.44% in EGFR mutant NSCLC, 0.17% in NSCLC patients). This study also firstly revealed that afatinib might exert superior antitumor activity to the 1G EGFR TKIs and chemotherapy in EGFR E709-T710delinsX mutant patients.

Predominance of the Rare EGFR Mutation p.L861Q in Tunisian Patients with Non-Small Cell Lung Carcinoma.

Objectives: Several new cancer therapies targeting signaling pathways involved in the growth and progression of cancer cells were developed as personalized medicine. Our study aimed to identify epidermal growth factor receptor (EGFR) mutations for TKI treatment in non-small-cell lung cancer (NSCLC) Tunisian patients. Methods: Analysis of the TKI sensitivity mutations in exons 18 to 21 of the EGFR gene and exon 15 of the B-raf gene was performed in 79 formalin fixed-paraffin embedded (FFPE) NSCLC samples using pyrosequencing. Results: EGFR mutations were detected in 34 cases among 79 (43%), with the predominance of the L861Q in exon 21 found in 35.3% of the cases (12 out of 34). Deletions in exon 19 were found in 8 cases (23.5%), and only one young male patient had the T790M mutation. Three patients harbored composite EGFR mutations (p.E746_A750del/p.L861R, p.E746_S752>V/p.S768I, and p.G719A/p.L861Q). Furthermore, the EGFR mutated status was significantly more frequent in female patients (p = 0.019), in non-smoker patients (p = 0.008), and in patients with metastasis (p = 0.044). Moreover, the B-raf V600E was identified in 5 EGFR negative patients among 39 analyzed samples (13.15%). Conclusion: The p.L861Q localized in exon 21 of the EGFR gene was the most common mutation identified in our patients (35.3%), whereas the “classic” EGFR mutations such as Del19 and p.L858R were found in 23.5% and 11.7% of the cases, respectively. Interestingly, most of p.L861X mutation-carrying patients showed good response to TKI treatment. Altogether, our findings suggest a particular distribution of the EGFR-TKIs sensitivity mutations in Tunisian NSCLC patients.

Features of patients with advanced EGFR-mutated non-small cell lung cancer benefiting from immune checkpoint inhibitors.

BackgroundAlthough immune checkpoint inhibitors (ICIs) generally show poor therapeutic efficacy in patients with epidermal growth factor receptor (EGFR) mutations, certain research indicate that a small proportion of these patients do respond to ICIs. The present study sought to identify the features of patients with EGFR mutations who might benefit from ICIs from multiple studies and discussed the optimal treatment paradigm for advanced non-small cell lung cancer (NSCLC) patients with EGFR mutations.MethodsThe profiles of 114 advanced NSCLC patients with EGFR mutations who received ICIs treatment were retrospectively reviewed. EGFR subtypes, programmed cell death ligand 1 (PD-L1) expression, and clinical characteristics regarding their impact on the efficacy of ICIs were investigated.ResultsPatients with major EGFR mutations (L858R or 19Del) had a shorter progression-free survival (PFS) and a lower objective response rate (ORR) as compared to patients with rare (20ins or G719X) and other EGFR mutations. Although not statistically significant, median overall survival (OS) tended to be longer in patients with negative (<1%) PD-L1 expression than with positive (≥1%) PD-L1 expression (15.61 vs. 7.40 months, p = 0.138). Median PFS and OS were significantly shorter in heavily treated patients (prior lines of therapy ≥3 lines vs. <3 lines: mPFS, 1.80 vs. 2.50 months, p = 0.003; mOS, 6.70 vs. 14.00 months, p = 0.031). ORR was also lower in patients who had received ≥3 prior lines of therapy compared to in those <3 prior lines of therapy (0.00% vs. 21.67%, p = 0.002).ConclusionPatients with major EGFR mutations showed poorer responses to ICIs than those with rare EGFR mutations. EGFR-mutated patients with lower PD-L1 expression showed a trend towards a longer OS after receiving ICIs. ICIs should be administered as early as possible to previously treated EGFR-mutated NSCLC patients. ICI-based combined therapies may be a direction for treatment of these patient subtypes in the future.

What do we know about the molecular and biological features of EGFR in glioblastomas and non-small cell lung cancer?

The EGFR mutation is one of the most common mutations in malignant neoplasms. The epidermal growth factor receptor (EGFR) is a growth factor receptor that induces cell differentiation and proliferation when activated by binding one of its ligands. The receptor is located on the cell surface, where ligand binding activates a tyrosine kinase in the intracellular region of the receptor. The tyrosine kinase phosphorylates a number of intracellular substrates and further activates pathways leading to cell growth, DNA synthesis and oncogene expression. Gene amplification is a process characterized by an increase in the copy number of a restricted region in the chromosome shoulder, which is associated with overexpression of the corresponding amplified gene. Amplification of the EGFR gene is detected in about 40% of glioblastoma cases. It should be noted that EGFR gene amplification is accompanied by the acquisition of many mutations, which include intragenic deletions and point mutations. The most common EGFR mutation in glioblastomas of the brain is a deletion in exon 2-7 (EGFRvIII) frame, which occurs in 50% of all cases of EGFR-amplified glioblastoma. Despite great advances in molecular biology and targeted therapies, patients with non-small cell lung cancer (NSCLC) and glioblastoma still lead in mortality. Most of them have “classical” EGFR mutations (deletions in exon 19 and 21), but 15-20% of patients have rare mutations, which most often include point mutations, deletions and insertions in exon 18 and 25. Thus, rare EGFR mutations are a promising diagnostic and therapeutic target in cancer. This review summarizes data on the role of EGFR in the carcinogenesis of NMPL and glioblastoma. The literature search was performed using the Pubmed database.

Abstract 75: Highly multiplexed EGFR mutation detection from liquid biopsy samples using the 6-color Crystal Digital PCR™

Abstract Liquid biopsies are a minimally invasive sampling approach to overcome the heterogeneity of tumors and represent a valuable source of circulating tumor DNA (ctDNA) for oncological biomarker analysis. ctDNA measurements require a highly sensitive and reliable detection technology to quantify often low-level genetic aberrations within a high background of wild-type sequences. Digital PCR emerged as a powerful technology for the next-generation analysis of liquid biopsies. Stilla Technologies' 6-color naica® system is an ultrasensitive, easy-to-use digital PCR platform capable of simultaneously and precisely quantifying high numbers of biomarkers in a single reaction. Non-small cell lung cancer (NSCLC) is a leading cause of cancer mortality worldwide. Epidermal growth factor receptor (EGFR) is frequently mutated in NSCLC. A handful of anti-EGFR Tyrosine Kinase Inhibitor therapies are approved by the FDA; however, most patients develop resistance over time to these treatments. Both monitoring primary EGFR mutations to predict treatment response and precociously detecting resistance mutations to adapt treatments promptly through ctDNA analysis stand to improve the effectiveness of NSCLC patient management. Stilla has developed a highly multiplexed 6-color Crystal Digital PCR EGFR kit detecting more than 90% of EGFR mutations described in NSCLC from ctDNA. The assay detects 32 common and rare somatic EGFR mutations in exons 18, 19, 20, and 21, including both activating and resistant mutations. In this work, we evaluated the sensitivity, precision and specificity of the EGFR 6-color Crystal Digital PCR assay highly specific and sensitive for the detection of EGFR mutations, with a Limit of Detection in a high background of wild-type DNA ranging from 0.30 to 0.46 cp/μL (with observed MAFs ranging from 0.06 to 0.09%). Moreover, a high concordance was observed between those EGFR results obtained for NSCLC ctDNA samples using 6-color Crystal Digital PCR and other technologies. With a rapid time to results and straightforward ctDNA analysis workflow, Crystal Digital PCR on the naica system promises ultrasensitive, highly multiplexed 6-color mutation detection, maximizing the information obtained from precious samples. Citation Format: Cécile Jovelet, Myrtille Remy, Noémie Pata-Merci, Damien Vasseur, Ludovic Lacroix, Claudia Labrador-Rached, Allison C. Mallory. Highly multiplexed EGFR mutation detection from liquid biopsy samples using the 6-color Crystal Digital PCR™ [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 75.

Distribution and favorable prognostic implication of genomic EGFR alterations in IDH-wildtype glioblastoma.

We aimed to evaluate the mutation profile, transcriptional variants, and prognostic impact of the epidermal growth factor receptor (EGFR) gene in isocitrate dehydrogenase (IDH)-wildtype glioblastomas (GBMs). We sequenced EGFR, evaluated the EGFR splicing profile using a next-generation sequencing oncopanel, and analyzed the outcomes in 138 grade IV IDH-wildtype GBM cases. EGFR mutations were observed in 10% of GBMs. A total of 23.9% of the GBMs showed EGFR amplification. Moreover, 25% of the EGFR mutations occurred in the kinase domain. Notably, EGFR alterations were a predictor of good prognosis (p=0.035). GBM with EGFR alterations was associated with higher Karnofsky Performance Scale scores (p=0.014) and lower Ki-67 scores (p=0.005) than GBM without EGFR alterations. EGFRvIII positivity was detected in 21% of EGFR-amplified GBMs. We identified two other EGFR variants in GBM cases with deletions of exons 6-7 (Δe 6-7) and exons 2-14 (Δe 2-14). In one case, the initial EGFRvIII mutation transformed into an EGFR Δe 2-14 mutation during recurrence. We found that the EGFR gene profiles of GBM differ among cohorts and that EGFR alterations are good prognostic markers of overall survival in patients with IDH-wildtype GBM. Additionally, we identified rare EGFR variants with longitudinal and temporal transformations of EGFRvIII.

Uncommon EGFR mutations in lung carcinoma: features and treatment outcomes in a retrospective French cohort.

BackgroundThe best management for rare epidermal growth factor receptor (EGFR) mutations in advanced non-small cell lung carcinoma (NSCLC) remains uncertain. The literature indicates that response to usual treatment could differ in certain subgroups such as exon 20 insertion/duplication (E20ID), other single uncommon mutation (OSUM), and EGFR complex mutation (ECM).MethodsIn this observational, regional, multi-center, retrospective study, we gathered data on uncommon EGFR mutations in NSCLC from 2007 to 2021. We analyzed patient characteristics, prognostic factors and treatment outcomes [objective response rate (ORR), disease control rate (DCR), progression free survival (PFS) and overall survival (OS)].ResultsAmong 119 patients with an uncommon EGFR mutant, 34 harbored E20ID, 23 ECM, and 62 OSUM. There were significantly more non-smokers in E20ID. Female gender and performance status <2 were associated with a better prognosis. Among the 97 metastatic patients with available data for 1st line treatment, median estimated OS was 21 months (95% CI: 18–31 months), with better non-significant OS for ECM. Median estimated PFS was 7 months (95% CI: 4–9 months). We found significant differences in ORR, DCR and PFS favoring 1st line chemotherapy for E20ID, whereas the outcomes for OSUM and ECM were more favorable for tyrosine kinase inhibitor (TKI) (mainly 2nd and 3rd generation).ConclusionsThere were variations in treatment outcomes among subgroups in our cohort. Exon 20 insertions showed better ORR and PFS with 1st line chemotherapy compared to TKI. Conversely, other rare EGFR mutations including ECM had better ORR and PFS with TKI than chemotherapy. There was no significant difference in OS among treatment groups overall or within rare mutation subgroups.

EGFR mutations in lung carcinomas: Mutation profile and survival analysis.

e20518 Background: Epidermal growth factor receptor (EGFR) mutation have been demonstrated to be both predictive and prognostic for patients with metastatic lung cancer. The administration of EGFR tyrosine kinase inhibitors (TKIs) has improved survival in this group of patients. Several generations of EGFR TKIs are currently available. The EGFR mutations have been divided into common and rare. The common mutations include Exon 19 deletion and Exon 21 L858R mutations and rest are grouped as rare. The presence of visceral metastasis in the brain and liver are usually portends a poor prognosis. Methods: We conducted a retrospective analysis of lung cancer patients who attended our hospital outpatient department from 2017 to 2021. The prevalence, demographics and clinical profile of EGFR common and rare mutations were studied using descriptive statistics. Survival of EGFR mutated patients was plotted using Kaplan Meier plots. SPSS was used for statistical analysis. Results: The prevalence of EGFR mutation among metastatic lung cancer was 14.10% (161/1148). The median age of the group was 60 years (23- 104 years). Smokers with EGFR mutations were 11.8% (n = 19). Male to Female ratios was 76:85 (47.2% and 52.8%). Three patients with squamous cell carcinoma exhibited EGFR mutation. Most common EGFR TKI used was Gefitnib. Osimertinib was used in 13 patients (1.4%). The percentage of common mutations were 85.75% (N = 132) and rare mutations were 14.3% (n = 22). The type of mutations could not be identified in 10 patients. The percentage of patients with exon 19 deletion were 63% (n = 97) and L858R were 24.7% (n = 38). Visceral metastasis (brain and liver) was seen in 47 patients (n = 29.2%). Brain progression was seen in 32 patients (n = 19.9%). The survival of patients with EGFR exon 19 deletion and L858R mutation was 16.36 + 8.97 months and 15.97+ 10.93 months, Survival among patients with common mutation was 16.20 + 9.57 months and among rare mutation was 13.43 + 12.19 months. Median Survival period of patients with visceral metastasis was 12 months (0 to 38 months). Conclusions: In our retrospective study, there was no significant difference between survival among common and rare EGFR mutations.

Mefatinib as first-line treatment of patients with advanced non–small cell lung cancer harboring rare EGFR mutations.

9102 Background: Mefatinib is a novel, second-generation, irreversible epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitor (TKI). A Phase Ib/II study has showed promising efficacy in patients with advanced EGFR (19del/L858R) mutant non-small cell lung cancer (NSCLC). This study is aimed to assess the efficacy and safety of mefatinib as first-line therapy for advanced rare EGFR mutations (G719X/S768I/L861Q) NSCLC. Methods: In this phase II study, we enrolled patients with stage IIIB-IV lung adenocarcinoma with at least one mutation in G719X, L861Q, and S768I who hadn¡¯t received front-line anticancer therapy. Other concurrent EGFR mutations were allowed with the exception of Ex19del, L858R, and exon 20 insertions. Eligible patients were treated with mefatinib 80 mg orally once daily. The primary endpoint was objective response rate (ORR) according to RECIST 1.1 criteria. Results: A total of 21 patients (median age 57.6, 47.62% male) have been enrolled, 80.95% with G719X, 33.3% S768I, and 19.05% L861Q. Six (28.57%) patients had concurrent mutations of G719X and S768I, and one (4.76%) patient had co-mutations of G719X and L861Q. As of data cut-off (Jan, 6, 2022), median follow-up was 25.1 months. Among the 21 efficacy evaluable patients, ORR was 85.71% (95% CI, 63.66-96.95) with a duration of response (DOR) of 22.2 months (95% CI, 8.4-NA). Disease control rate (DCR) was 100% (95% CI, 83.89-100.00). Median progression-free survival (mPFS) was 20.6 months (95% CI, 8.3-NA). Median overall survival (OS) was not reached.. The most common treatment-related adverse events (TRAEs) were rash (20, 95.24%), diarrhea (19, 90.48%), stomatitis (15, 71.43%), and pandactilitis (9, 42.86%). Grade 3 TRAEs were reported in 47.63% patients. Common Grade 3 TRAEs (¡Ý5%) included diarrhea (8, 38.10%) and rash (5, 23.81%). No ¡ÝGrade 4 TRAE or treatment-related SAE reported. 33.33% (n=7) of patients experienced dose reduction due to AEs (mainly diarrhea and rash). All TRAEs were reversible and remained stable or recovered without sequelae after dose reduction. None of the patients discontinued treatment or died due to TRAE. Conclusions: Mefatinib has shown promising anti-tumor activity and a favorable safety profile in patients with advanced NSCLC harboring rare EGFR mutations. Clinical trial information: CTR20190110. [Table: see text]