The EGFR Exon 19 Mutant L747-A750>P Exhibits Distinct Sensitivity to Tyrosine Kinase Inhibitors in Lung Adenocarcinoma

Label-free fluorescent sensor for sensitive detection of ctDNA based on water stabilized CsPbBr3 nanosheet

The detection of circulating tumor DNA (ctDNA), as a practical liquid biopsy technique, was of great significance for the study of cancer diagnosis and prognosis. However, reported methods for detection ctDNA still have some limitations, such as tedious process and high cost. In this study, CsPbBr3 nanosheet (CsPbBr3 NS) with high water stability was prepared by etching, and its fluorescence intensity could be stably stored for 1 year. The Ti3C2Tx possessed high quenching efficiency for CsPbBr3 NS and the HOMO-LUMO orbital study revealed that the PET mechanism was responsible for fluorescence quenching. And the Ti3C2Tx showed stronger affinity towards single-stranded DNA (ssDNA), as compared with double-stranded DNA (dsDNA). The probe ssDNA could be adsorbed on the surface of Ti3C2Tx through π-π stacking. After the targets were recognized by probe ssDNA to form dsDNA, its affinity with Ti3C2Tx decreased and the active site of Ti3C2Tx recovered, causing a high quenching efficiency on CsPbBr3 NS. Based on this, a label-free fluorescent biosensor was designed for the sensitive detection of ctDNA (EGFR 19 Dels for non-small cell lung cancer, NSCLC). Under the optimal experimental conditions, this biosensor exhibited a detection limit of 180 fM and a linear range of 50 pM-350 pM with amplification of magnetic beads through strand displacement reaction. In addition, this sensor was applied to the detection of ctDNA in serum samples and cells lysates. This method for ctDNA detection was expected to have great potential for biomarker detection in the field of liquid biopsy.

Machine Learning in Diagnosis and Prognosis of Lung Cancer by PET-CT

As a disease with high morbidity and high mortality, lung cancer has seriously harmed people's health. Therefore, early diagnosis and treatment are more important. PET/CT is usually used to obtain the early diagnosis, staging, and curative effect evaluation of tumors, especially lung cancer, due to the heterogeneity of tumors and the differences in artificial image interpretation and other reasons, it also fails to entirely reflect the real situation of tumors. Artificial intelligence (AI) has been applied to all aspects of life. Machine learning (ML) is one of the important ways to realize AI. With the help of the ML method used by PET/CT imaging technology, there are many studies in the diagnosis and treatment of lung cancer. This article summarizes the application progress of ML based on PET/CT in lung cancer, in order to better serve the clinical. In this study, we searched PubMed using machine learning, lung cancer, and PET/CT as keywords to find relevant articles in the past 5 years or more. We found that PET/CT-based ML approaches have achieved significant results in the detection, delineation, classification of pathology, molecular subtyping, staging, and response assessment with survival and prognosis of lung cancer, which can provide clinicians a powerful tool to support and assist in critical daily clinical decisions. However, ML has some shortcomings such as slightly poor repeatability and reliability.

A destabilizing Y891D mutation in activated EGFR impairs sensitivity to kinase inhibition

EGFR tyrosine kinase inhibitors (TKIs) have transformed the treatment of EGFR-mutated non-small cell lung carcinoma (NSCLC); however, therapeutic resistance remains a clinical challenge. Acquired secondary EGFR mutations that increase ATP affinity and/or impair inhibitor binding are well-described mediators of resistance. Here we identify a de novo EGFR Y891D secondary alteration in a NSCLC with EGFR L858R. Acquired EGFR Y891D alterations were previously reported in association with resistance to first generation EGFR TKIs. Functional studies in Ba/F3 cells demonstrate reduced TKI sensitivity of EGFR L858R + Y891D, with the greatest reduction observed for first and second generation TKIs. Unlike other EGFR mutations associated with TKI resistance, Y891D does not significantly alter ATP affinity or promote steric hindrance to inhibitor binding. Our data suggest that the Y891D mutation destabilizes EGFR L858R, potentially generating a population of misfolded receptor with preserved signaling capacity but reduced sensitivity to EGFR inhibitors. These findings raise the possibility of protein misfolding as a mechanism of resistance to EGFR inhibition in EGFR-mutated NSCLC.

Non-small cell lung cancer cells with uncommon EGFR exon 19delins variants respond poorly to third-generation EGFR inhibitors

BACKGROUND

This study compared the clinical efficacy of first-, second-, and third-generation tyrosine kinase inhibitors (TKIs) in previously untreated non-small cell lung cancer (NSCLC) patients harboring uncommon epidermal growth factor receptor (EGFR) exon 19delins variants.

METHODS

We retrospectively analyzed the clinical outcomes of NSCLC patients with EGFR exon 19delins mutations who were treated with third- and first-generation EGFR TKIs. In vitro and in vivo studies were conducted to verify the sensitivity of these mutations to distinct generations of TKIs. Molecular simulation was used to investigate the structural characteristics of the EGFR mutant molecules.

RESULTS

In a multicenter cohort of 1,526 patients, 37 (2.4 %) had uncommon EGFR 19delins mutations. Twenty-four patients were treated with first-generation EGFR TKIs, and third-generation TKIs were administered to ten patients as frontline therapy. Patients carrying EGFR exon 19delins mutations who were given third-generation TKIs exhibited comparatively shorter progression-free survival (PFS) and overall survival (OS) in relation to those who received first-generation EGFR inhibitors; median PFS: 6.9 months vs. 19.1 months (p < 0.001), Median OS: 19.1 months vs. 32.6 months (p < 0.001). In vivo and in vitro studies revealed that uncommon EGFR 19delins variants exhibit limited sensitivity to third-generation EGFR inhibitors in contrast to first- and second-generation EGFR inhibitors. The molecular binding affinity of third-generation EGFR TKIs toward uncommon EGFR 19delins mutations was less than that of first- and second-generation EGFR inhibitors.

CONCLUSIONS

Uncommon EGFR 19delins variants respond poorly to third-generation EGFR inhibitors in NSCLC. Uncommon EGFR 19delins mutations may serve as an unfavorable predictive factor for the efficacy of third-generation EGFR TKI therapy, offering potential guidance for future clinical decision-making.

Coevolution-based computational approach to detect resistance mechanism of epidermal growth factor receptor

Tyrosine kinase epidermal growth factor receptor (EGFR) correlates the neoplastic cell metastasis, angiogenesis, neoplastic incursion, and apoptosis. Due to the involvement of EGFR in these biological processes, it becomes a most potent target for treating non-small cell lung cancer (NSCLC). The tyrosine kinase inhibitors (TKI) have endorsed high efficacy and anticipation to patients but unfortunately, within a year of treatment, drug targets develop resistance due to mutations. The present study detected the compensatory mutations in EGFR to know the evolutionary mechanism of drug resistance. The results of this study demonstrate that compensatory mutations enlarge the drug-binding pocket which may lead to the altered orientation of the ligand (gefitinib and erlotinib) causing drug resistance. This indicates that coevolutionary forces play a significant role in fine-tuning the structure of EGFR protein against the drugs. The analysis provides insight into the evolution-induced structural aspects of drug resistance changes in EGFR which in turn be useful in designing drugs with better efficacy.

Clinical outcomes of advanced NSCLC patients with different EGFR exon 19 deletion subtypes treated with first-line tyrosine kinase inhibitors: A single-center ambispective cohort study

BACKGROUND

Clinical significance of various subtypes of epidermal growth factor receptor (EGFR) exon 19 deletion (ex19del) mutation in non-small cell lung cancer (NSCLC) remains unclear.

METHODS

We analyzed EGFR ex19del subtypes in NSCLC patients receiving first-line tyrosine kinase inhibitor (TKI) therapy at our center (January 2018-June 2022) and correlated them with median progression-free survival (mPFS) and median overall survival (mOS).

RESULTS

We identified 17 different EGFR ex19del variants in 101 patients. Between the classic (E746_A750del, 64.4%) and nonclassic groups (the rest variants), no significant difference was observed in mPFS (13.5 vs. 19.3 months, p = 0.18) or mOS (44.1 vs. 77.0 months, p = 0.06). mPFS showed no significant difference between ex19del subgroups classified based on the presence of insertion (ex19delins), starting position or length of deletion. However, patients with ex19delins starting at E746 showed longer mPFS than the others (29.7 vs. 12.5 months, p = 0.04), and patients with ex19del of 15 nucleotides had shorter mOS than the others (44.1 vs. 77.0 months, p = 0.03). In multivariate analysis, ex19delins independently predicted a better PFS (HR = 0.311, p = 0.03); however, 15 nucleotide deletion was no longer associated with OS (HR = 0.181, p = 0.11). Secondary T790M mutation incidence was significantly higher in the ex19del subgroup starting at E746 than the others (64.7% vs. 30.8%, p = 0.04).

CONCLUSIONS

Our study revealed potential differences in TKI efficacy, resistance mechanism, and prognosis of various EGFR ex19del subtypes in NSCLC, underscoring the need for precise selection of first-line therapy.

Biosensors for the detection of lung cancer biomarkers: A review on biomarkers, transducing techniques and recent graphene-based implementations

Lung cancer remains the leading cause of cancer-related death. In addition to chest X-rays and computerised tomography, the detection of cancer biomarkers serves as an emerging diagnostic tool for lung cancer. This review explores biomarkers including the rat sarcoma gene, the tumour protein 53 gene, the epidermal growth factor receptor, the neuron-specific enolase, the cytokeratin-19 fragment 21-1 and carcinoembryonic antigen as potential indicators of lung cancer. Biosensors, which utilise various transduction techniques, present a promising solution for the detection of lung cancer biomarkers. Therefore, this review also explores the working principles and recent implementations of transducers in the detection of lung cancer biomarkers. The transducing techniques explored include optical techniques, electrochemical techniques and mass-based techniques for detecting biomarkers and cancer-related volatile organic compounds. Graphene has outstanding properties in terms of charge transfer, surface area, thermal conductivity and optical characteristics, on top of allowing easy incorporation of other nanomaterials. Exploiting the collective merits of both graphene and biosensor is an emerging trend, as evidenced by the growing number of studies on graphene-based biosensors for the detection of lung cancer biomarkers. This work provides a comprehensive review of these studies, including information on modification schemes, nanomaterials, amplification strategies, real sample applications, and sensor performance. The paper concludes with a discussion of the challenges and future outlook of lung cancer biosensors, including scalable graphene synthesis, multi-biomarker detection, portability, miniaturisation, financial support, and commercialisation.

Efficacy of Osimertinib in Patients with Lung Cancer Positive for Uncommon EGFR Exon 19 Deletion Mutations

PURPOSE

The uncommon EGFR exon 19 deletion (ex19del), L747_A750>P, demonstrates reduced sensitivity to osimertinib compared with the common ex19del, E746_A750del in preclinical models. The clinical efficacy of osimertinib in patients with non-small cell lung cancer harboring L747_A750>P and other uncommon ex19dels is not known.

EXPERIMENTAL DESIGN

The AACR GENIE database was interrogated to characterize the frequency of individual ex19dels relative to other variants, and a multicenter retrospective cohort was used to compare clinical outcomes for patients with tumors harboring E746_A750del, L747_A750>P, and other uncommon ex19dels who received osimertinib in the first line (1L) or in second or later lines of therapy and were T790M+ (≥2L).

RESULTS

ex19dels comprised 45% of EGFR mutations, with 72 distinct variants ranging in frequency from 28.1% (E746_A750del) to 0.03%, with L747_A750>P representing 1.8% of the EGFR mutant cohort. In our multi-institutional cohort (N = 200), E746_A750del was associated with significantly prolonged progression-free survival (PFS) with 1L osimertinib versus L747_A750>P [median 21.3 months (95% confidence interval, 17.0-31.7) vs. 11.7 months (10.8-29.4); adjusted HR 0.52 (0.28-0.98); P = 0.043]. Osimertinib efficacy in patients with other uncommon ex19dels varied on the basis of the specific mutation present.

CONCLUSIONS

The ex19del L747_A750>P is associated with inferior PFS compared with the common E746_A750del mutation in patients treated with 1L osimertinib. Understanding differences in osimertinib efficacy among EGFR ex19del subtypes could alter management of these patients in the future.

Different treatment efficacies and T790M acquisition of EGFR-TKIs on NSCLC patients with variable Del-19 subtypes of EGFR

EGFR exon 19 deletion (Del-19) comprises multiple advanced NSCLC subtypes. EGFR-tyrosine kinase inhibitor (TKI) efficacy and T790M acquisition in various Del-19 subtypes is unknown. We prospectively collected tissue samples from patients harboring NSCLC with Del-19 between 2006 and 2020. We evaluated EGFR-TKI treatment effectiveness among the different Del-19 subtypes. We collected 1391 NSCLC samples from 892 patients with Del-19, and the most common subtype was del E746-A750 (67.5%). 741 patients had taken first- or second-generation EGFR-TKIs. There were no significant differences in response rates between patients with different Del-19 subtypes (P = .630). Patients with indel E746 had the longest median PFS (14.6 months), but those with non-LRE deletions had the shortest PFS (8.9 months; P = .002). For OS analysis, patients with indel E746 also had the longest OS (34.1 months), but those with non-LRE deletions had the shortest OS (21.1 months; P = .046). Patients with different Del-19 subtypes showed no significant differences in the T790M acquisition rates (P = .443). Among the 151 patients with acquired T790M who received third-generation EGFR-TKIs, the Del-19 subtype was not associated with different RR and PFS. In vitro cellular viability and activation of the EGFR pathway analysis were consistent with the clinical findings. In conclusion, compared with del E746-A750, indel E746 was associated with longer PFS and OS, but the non-LRE subtype was correlated with shorter survival prognosis. There were no significant differences in the acquired T790M rate and treatment effectiveness of subsequent third-generation EGFR-TKIs between various Del-19 subgroups.

Osimertinib in NSCLC With Atypical EGFR-Activating Mutations: A Retrospective Multicenter Study

Introduction

EGFR mutations drive a subset of NSCLC. Patients harboring the common EGFR mutations, deletion of exon 19 and L858R, respond well to osimertinib, a third-generation tyrosine kinase inhibitor. Nevertheless, the effect of osimertinib on NSCLC with atypical EGFR mutations is not well described. This multicenter retrospective study evaluates the efficacy of osimertinib among patients with NSCLC harboring atypical EGFR mutations.

Methods

Patients with metastatic NSCLC treated with osimertinib, harboring at least one atypical EGFR mutation, excluding concurrent deletion of exon 19, L858R, or T790M mutations, from six U.S. academic cancer centers were included. Baseline clinical characteristics were collected. The primary end point was the time to treatment discontinuation (TTD) of osimertinib. Objective response rate by the Response Evaluation Criteria in Solid Tumors version 1.1 was also assessed.

Results

A total of 50 patients with NSCLC with uncommon EGFR mutations were identified. The most frequent EGFR mutations were L861Q (40%, n = 18), G719X (28%, n = 14), and exon 20 insertion (14%, n = 7). The median TTD of osimertinib was 9.7 months (95% confidence interval [CI]: 6.5-12.9 mo) overall and 10.7 months (95% CI: 3.2-18.1 mo) in the first-line setting (n = 20). The objective response rate was 31.7% (95% CI: 18.1%-48.1%) overall and 41.2% (95% CI: 18.4%-67.1%) in the first-line setting. The median TTD varied among patients with L861Q (17.2 mo), G719X (7.8 mo), and exon 20 insertion (1.5 mo) mutations.

Conclusions

Osimertinib has activity in patients with NSCLC harboring atypical EGFR mutations. Osimertinib activity differs by the type of atypical EGFR-activating mutation.

Structure-Guided Strategies of Targeted Therapies for Patients with EGFR-Mutant Non-Small Cell Lung Cancer

Oncogenic mutations within the EGFR kinase domain are well-established driver mutations in non-small cell lung cancer (NSCLC). Small-molecule tyrosine kinase inhibitors (TKIs) specifically targeting these mutations have improved treatment outcomes for patients with this subtype of NSCLC. The selectivity of these targeted agents is based on the location of the mutations within the exons of the EGFR gene, and grouping mutations based on structural similarities has proved a useful tool for conceptualizing the heterogeneity of TKI response. Structure-based analysis of EGFR mutations has influenced TKI development, and improved structural understanding will inform continued therapeutic development and further improve patient outcomes. In this review, we summarize recent progress on targeted therapy strategies for patients with EGFR-mutant NSCLC based on structure and function analysis.

Discovery of HCD3514 as a potent EGFR inhibitor against C797S mutation in vitro and in vivo

Osimertinib (AZD9291), a third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKI), has significantly improved the survival of non-small cell lung cancer (NSCLC) patients with EGFR^T790M mutation, the major mechanism of acquired resistance to first-generation EGFR TKI. However, resistance to AZD9291 arises eventually and EGFR^C797S mutation was reported to be a major resistance mechanism. Thus, it is highly valuable to develop novel EGFR fourth-generation inhibitors targeting C797S mutation to override the acquired resistance. In this study, we identified HCD3514 as a novel EGFR fourth-generation inhibitors targeting C797S triple mutation. It strongly inhibited EGFR^{L858R/T790M/C797S} and EGFR^{19del/T790M/C797S} mutations with IC₅₀ values of 1.0 and 2.0 nM, respectively. HCD3514 dose-dependently inhibited the activation of EGFR in both engineered BaF3 cells and tumor cells harboring EGFR^C797S triple mutant and thus effectively suppressed the proliferation of the cells. Moreover, HCD3514 caused a dose-dependent increase of apoptosis in C797S triple mutant cells accompanied by increased levels of cleaved caspase-3 and cleaved PARP. Furthermore, HCD3514 induced tumor growth inhibition in EGFR^{19del/T790M/C797S} xenograft model as a single oral agent by decreasing the activation of EGFR. In addition to EGFR^C797S triple mutations, HCD3514 also potently and selectively inhibited EGFR^T790M double mutations (L858R/T790M and 19del/T790M). Collectively, HCD3514 is a highly selective and potent EGFR inhibitor against EGFR^C797S triple mutations as well as EGFR^T790M double mutations and is confirmed potently anti-tumor activity in preclinical models.

Precision immunointerception of EGFR-driven tumorigenesis for lung cancer prevention

Epidermal growth factor receptor (EGFR) mutations occur in about 50% of lung adenocarcinomas in Asia and about 15% in the US. EGFR mutation-specific inhibitors have been developed and made significant contributions to controlling EGFR mutated non-small cell lung cancer. However, resistance frequently develops within 1 to 2 years due to acquired mutations. No effective approaches that target mutant EGFR have been developed to treat relapse following tyrosine kinase inhibitor (TKI) treatment. Vaccination against mutant EGFR is one area of active exploration. In this study, we identified immunogenic epitopes for the common EGFR mutations in humans and formulated a multi-peptide vaccine (E^mut Vax) targeting the EGFR L858R, T790M, and Del19 mutations. The efficacy of the E^mut Vax was evaluated in both syngeneic and genetic engineered EGFR mutation-driven murine lung tumor models with prophylactic settings, where the vaccinations were given before the onset of the tumor induction. The multi-peptide E^mut Vax effectively prevented the onset of EGFR mutation-driven lung tumorigenesis in both syngeneic and genetically engineered mouse models (GEMMs). Flow cytometry and single-cell RNA sequencing were conducted to investigate the impact of E^mut Vax on immune modulation. E^mut Vax significantly enhanced Th1 responses in the tumor microenvironment and decreased suppressive Tregs to enhance anti-tumor efficacy. Our results show that multi-peptide E^mut Vax is effective in preventing common EGFR mutation-driven lung tumorigenesis, and the vaccine elicits broad immune responses that are not limited to anti-tumor Th1 response.

Biochemical and structural basis for differential inhibitor sensitivity of EGFR with distinct exon 19 mutations

Tyrosine kinase inhibitors (TKIs) are used to treat non-small cell lung cancers (NSCLC) driven by epidermal growth factor receptor (EGFR) mutations in the tyrosine kinase domain (TKD). TKI responses vary across tumors driven by the heterogeneous group of exon 19 deletions and mutations, but the molecular basis for these differences is not understood. Using purified TKDs, we compared kinetic properties of several exon 19 variants. Although unaltered for the second generation TKI afatinib, sensitivity varied significantly for both the first and third generation TKIs erlotinib and osimertinib. The most sensitive variants showed reduced ATP-binding affinity, whereas those associated with primary resistance retained wild type ATP-binding characteristics (and low K_{M, ATP}). Through crystallographic and hydrogen-deuterium exchange mass spectrometry (HDX-MS) studies, we identify possible origins for the altered ATP-binding affinity underlying TKI sensitivity and resistance, and propose a basis for classifying uncommon exon 19 variants that may have predictive clinical value.

Ablative Radiotherapy as a Strategy to Overcome TKI Resistance in EGFR-Mutated NSCLC

Simple Summary

Most patients with EGFR-mutated NSCLC who receive treatment with targeted therapy will eventually develop resistance, meaning the therapy will lose its efficacy. Prior studies have shown a benefit to continuing to treat patients on TKI therapy despite limited progression of one or more sites of metastatic disease in EGFR-mutated NSCLC. Based on the data reviewed here, the use of radiation therapy to sites of disease progression is both efficacious and carries a low risk for side effects, with the added benefit of allowing patients to continue on TKI therapy.

Abstract

Tyrosine kinase inhibitor (TKI) therapy is the recommended first-line treatment for metastatic non-small-cell lung cancer (NSCLC) positive for epidermal growth factor receptor (EGFR) gene mutation. However, most individuals treated with TKI therapy for EGFR-mutant NSCLC will develop tumor resistance to TKI therapy. Therapeutic strategies to overcome TKI resistance are the topic of several ongoing clinical trials. One potential strategy, which has been explored in numerous trials, is the treatment of progressive sites of disease with stereotactic body radiation treatment (SBRT) or stereotactic radiosurgery (SRS). We sought to review the literature pertaining to the use of local ablative radiation therapy in the setting of acquired resistance to TKI therapy and to discuss stereotactic radiation therapy as a strategy to overcome TKI resistance.

Allele-specific activation, enzyme kinetics, and inhibitor sensitivities of EGFR exon 19 deletion mutations in lung cancer

Epidermal growth factor receptor (EGFR) mutations are detected in approximately 30% of all lung adenocarcinomas, and the most common EGFR mutation occurring in ∼50% of patients is termed “exon 19 deletion” (ex19del). Despite the existence of dozens of different genomic variants comprising what is generically referred to clinically as ex19del, clinicians currently do not distinguish between ex19del variants in considering treatment options, and differences between ex19del variants are largely unstudied in the broader scientific community. Herein, we describe functional differences between distinct EGFR ex19del variants attributable to the structural features of each variant. These findings suggest a possible explanation for observed differences in patient outcomes stratified by ex19del subtype and reinforce the need for allele-specific considerations in clinical treatment decision-making.

Oncogenic mutations within the epidermal growth factor receptor (EGFR) are found in 15 to 30% of all non–small-cell lung carcinomas. The term exon 19 deletion (ex19del) is collectively used to refer to more than 20 distinct genomic alterations within exon 19 that comprise the most common EGFR mutation subtype in lung cancer. Despite this heterogeneity, clinical treatment decisions are made irrespective of which EGFR ex19del variant is present within the tumor, and there is a paucity of information regarding how individual ex19del variants influence protein structure and function. Herein, we identified allele-specific functional differences among ex19del variants attributable to recurring sequence and structure motifs. We built all-atom structural models of 60 ex19del variants identified in patients and combined molecular dynamics simulations with biochemical and biophysical experiments to analyze three ex19del mutations (E746_A750, E746_S752 > V, and L747_A750 > P). We demonstrate that sequence variation in ex19del alters oncogenic cell growth, dimerization propensity, enzyme kinetics, and tyrosine kinase inhibitor (TKI) sensitivity. We show that in contrast to E746_A750 and E746_S752 > V, the L747_A750 > P variant forms highly active ligand-independent dimers. Enzyme kinetic analysis and TKI inhibition experiments suggest that E746_S752 > V and L747_A750 > P display reduced TKI sensitivity due to decreased adenosine 5′-triphosphate K_m. Through these analyses, we propose an expanded framework for interpreting ex19del variants and considerations for therapeutic intervention.

Site-specific insertion of endonuclease recognition sites into amplicons to improve post-PCR analysis sensitivity of gene mutation

Precise detection of low-frequency gene mutations surrounded by excess wild-type DNA is important in many aspects of medical fields. Most hybridization-based methods for high-resolution mutant allele analysis are hindered by competition of the complementary strand with single-strand probes for the target strand. Here, we demonstrate that site-specific insertion of endonuclease recognition sites into amplicons allows post-PCR generation of short dsDNA or ssDNA, whereby improves the sensitivity of both melting temperature analysis (MTA) and end-point detection following up. Using a three-staged PCR protocol, enrichment of target gene and incorporation of specific restriction sites in amplicons were ensued with hardly any loss in amplification efficiency and specificity. It enables simultaneous discrimination among a panel of totally 11 EGFR 19 exon deletion mutations via MTA after post-PCR digestion by either FokI only or cooperated with CRISPR-Cas12a, using SYBR green I. By replacement of one double-strand cleavage site with a nickase binding domain post-PCR generation of ssDNA of interest via strand displacement amplification (termed as iSDA) is realized. Our preliminary investigation shows that iSDA permits analysis of single nucleotide variants down to 0.1% allelic-frequency using end-point detection. Given the good compatibility with the majority of mutant-enrich PCR methods, we envision it would advance the current gene profiling technologies to a large extent.

Overall Survival Benefits of First-Line Treatments for Asian Patients with Advanced Epidermal Growth Factor Receptor-Mutated NSCLC Harboring Exon 19 Deletion: A Systematic Review and Network Meta-Analysis

Simple Summary

Survival benefits and clinical responsiveness have been exhibited by various generations of EGFR-tyrosine kinase inhibitors (TKIs) in numerous randomized-controlled trials for EGFR-mutated advanced non-small-cell lung cancer (NSCLC) over the past two decades. However, the efficacy, especially long-term overall survival (OS) for Asians harboring an exon 19 deletion (19del) in their NSCLC, remains uncertain. This systematic review and network meta-analysis evaluate the efficacy of all first-line treatments in Asian patients with advanced EGFR-mutated NSCLC harboring 19del. EGFR-TKIs and combination treatments demonstrated no OS benefits in comparison with standard chemotherapy treatments, although progression-free survival (PFS) benefits were revealed. Erlotinib plus bevacizumab, ramucirumab plus erlotinib, and osimertinib are the optimal regimens to prolong PFS for Asians with 19del. Further studies are warranted to investigate the resistance mechanisms and possible strategies for individuals harboring this common mutation.

Abstract

(1) Background: Randomized controlled trials (RCTs) have explored various primary treatments for individuals diagnosed as having later-stage epidermal growth factor receptor (EGFR)-mutated non-small-cell lung cancer. Nevertheless, the extent to which such treatments are efficacious, particularly with regard to overall survival (OS) rates of patients from Asia with exon 19 deletion (19del), has yet to be clarified. (2) Methods: A systematic review and frequentist network meta-analysis were conducted by obtaining pertinent studies from PubMed/MEDLINE Ovid, Embase, Cochrane Library, and trial registries, as well as various other sources. RCTs in which two or multiple treatments in the primary setting for patients from Asia with EGFR 19del were compared were included. This research has been recorded in the Prospective Register of Systematic Reviews (CRD 42022320833). (3) Results: A total of 2715 patients from Asia participated in 18 trials in which 12 different treatments were administered, which included: EGFR tyrosine kinase inhibitors (TKIs) (osimertinib, dacomitinib, afatinib, erlotinib, gefitinib, and icotinib), pemetrexed-based chemotherapy, pemetrexed-free chemotherapy, and combination treatments (gefitinib plus apatinib, erlotinib plus ramucirumab, erlotinib plus bevacizumab, and gefitinib plus pemetrexed-based chemotherapy). Such treatments were not significantly beneficial in terms of OS for patients from Asia who had 19del. It was demonstrated that erlotinib plus bevacizumab, ramucirumab plus erlotinib, and osimertinib consistently yielded the greatest benefits regarding progression-free survival benefit (P-scores = 94%, 84%, and 80%, respectively). Combination treatments resulted in increased toxicity, particularly gefitinib plus apatinib and erlotinib plus bevacizumab, causing the highest prevalence of grade ≥ 3 adverse events. Icotinib and osimertinib had the fewest grade ≥ 3 adverse events. Specific treatments were associated with a wide range of toxicity levels. (4) Conclusions: In patients from Asia with 19del, both EGFR-TKIs and treatments in which therapies were combined exhibited no OS benefits in comparison with standard chemotherapy treatments. Additional research is required to study TKIs’ resistance mechanisms and possible combined approaches for individuals harboring this common mutation.

Acquired Mechanisms of Resistance to Osimertinib-The Next Challenge

Simple Summary

Osimertinib has revolutionized the treatment of EGFR-mutated tumors. Its current applications include the first-line setting, second-line setting, as well as the adjuvant setting. Although it represents a milestone in the context of targeted therapy, inevitably all tumors develop an acquired resistance, some mechanisms involve EGFR, others do so through alternative pathways leading to a bypass in osimertinib inhibition. It is key to understand these acquired mechanisms of resistance, both in the clinical setting, as well as in preclinical models, in order to develop and contribute to the identification of possible therapeutic strategies to overcome this acquired resistance.

Abstract

EGFR-mutated tumors represent a significant percentage of non-small cell lung cancer. Despite the increasing use of osimertinib, a treatment that has demonstrated an outstanding clinical benefit with a tolerable toxicity profile, EGFR tumors eventually acquire mechanisms of resistance. In the last years, multiple mechanisms of resistance have been identified; however, after progressing on osimertinib, treatment options remain bleak. In this review, we cover the most frequent alterations and potential therapeutic strategies to overcome them.

Metabolic complete tumor response in a patient with epidermal growth factor receptor mutant non-small cell lung cancer treated with a reduced dose of afatinib

Tyrosine kinase inhibitors (TKIs) targeting epidermal growth factor receptor (EGFR) are the first-line treatment for EGFR-mutant non-small cell lung cancer. Toxicities related to EGFR-TKIs include skin rash, paronychia, and diarrhea, which in some cases can lead to dose reductions or treatment interruptions. Herein, we report the case of a 51-year-old woman affected by advanced adenocarcinoma harboring an exon 19 deletion in the EGFR gene, who was treated with second-generation EGFR-TKI following a scheduled gradual dose reduction to better manage toxicities. Following prescription labeling, treatment was initiated at a dose of 40 mg daily. After a few months, the dose was reduced to 30 mg daily owing to grade 3 skin toxicity. A metabolic complete tumor response was observed after 1 year of treatment, then therapy was continued at 20 mg daily, enabling disease stabilization. In conclusion, low dose afatinib was effective in an EGFR-mutant non-small cell lung cancer patient who required dose reductions to better manage toxicities.

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

Background

In the existing next generation sequencing (NGS) system, epidermal growth factor receptor (EGFR) exon 19 deletion-insertion (19delins) is still interpreted into the category of EGFR exon 19 deletion (19del). However, the controversy exists whether the two mutation types have the similar responses and resistant mechanisms to first-generation EGFR tyrosine kinase inhibitor (TKI) in non-small cell lung cancer (NSCLC) patients.

Methods

We successively and retrospectively reviewed the NGS data of 3054 patients diagnosed as advanced NSCLC from November 2017 to September 2020. Finally, 41 patients with EGFR 19delins mutation and 41 patients with EGFR 19del mutation who received first-generation EGFR TKIs as first-line therapy were included in the study.

Results

A total of 17 genotypes were identified in this study, including L747_P753delinsS (10/41), L747_A750delinsP (9/41), L747_T751delinsP (6/41) and E746_S752delinsV (3/41). Under the same baseline characteristics, the population of EGFR 19delins respond well to first line EGFR TKIs as well as those of EGFR 19del, with little difference in median progression-free survival (mPFS): 10.4 months vs. 13.1 months, p = 0.1076). Interestingly, patients with L747_T751delinsP seem to have a better mPFS than others (18.7 months vs. 13.1 months, p = 0.035). After the disease progression, both EGFR 19delins and EGFR 19del had similar rates of developing EGFR T790M mutation resistance (45.8% vs. 57.8%), and those receiving osimeritinib as second-line treatment obtain the similar survival benefits (mPFS: 12.0 months vs. 12.2 months (p = 0.97).

Conclusions

This retrospective cohort study furnish the evidence that therapeutic responses and survival of untreated NSCLC population with EGFR 19delins mutation are equal to those with common EGFR 19del mutation after administration of EGFR TKIs therapy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08942-x.

Mefatinib as first-line treatment of patients with advanced EGFR-mutant non-small-cell lung cancer: a phase Ib/II efficacy and biomarker study

EGFR inhibitors have revolutionized the treatment of advanced non-small-cell lung cancer (NSCLC). Mefatinib is a novel, bioavailable, second-generation, irreversible pan-EGFR inhibitor. This phase Ib/II open-label, single-arm, multi-center study investigated the efficacy, safety, biomarker, and resistance mechanisms of mefatinib in the first-line treatment of patients with advanced EGFR-mutant NSCLC. This study included 106 patients with EGFR-mutant stage IIIB-IV NSCLC who received first-line mefatinib at a daily dose of either 60 mg (n = 51) or 80 mg (n = 55). The primary endpoint was progression-free survival (PFS). Secondary endpoints were overall response rate (ORR), disease control rate (DCR), overall survival (OS), and safety. The cohort achieved an ORR of 84.9% and DCR of 97.2%. The median PFS was 15.4 months and the median OS was 31.6 months. Brain metastasis was detected in 29% of patients (n = 31) at diagnosis and demonstrated an ORR of 87.1%, PFS of 12.8 months, and OS of 25.2 months. Adverse events primarily involved skin and gastrointestinal toxicities, which were well-tolerated and manageable. Analyses of mutation profiles were performed using targeted sequencing of plasma samples at baseline, first follow-up 6 weeks from starting mefatinib therapy (F1), and at progression. Patients with concurrent TP53 mutations had comparable PFS as wild-type TP53 (14.0 vs 15.4 months; p = 0.315). Furthermore, circulating tumor DNA clearance was associated with longer PFS (p = 0.040) and OS (p = 0.002). EGFR T790M was the predominant molecular mechanism of mefatinib resistance (42.1%, 16/38). First-line mefatinib provides durable PFS and an acceptable toxicity profile in patients with advanced EGFR-mutant NSCLC.

Dose-dependence in acquisition of drug tolerant phenotype and high RYK expression as a mechanism of osimertinib tolerance in lung cancer

OBJECTIVE

Emergence of acquired resistance is almost inevitable during EGFR-tyrosine kinase inhibitor therapy for non-small-cell lung cancer (NSCLC) harboring EGFR mutations. Drug tolerance, a reversible state of drug insensitivity in the early phases of tyrosine kinase inhibitor therapy, is considered to serve as the basis of recurrent disease. Therefore, it is important to elucidate the molecular mechanisms of drug tolerance.

MATERIALS AND METHODS

Five EGFR-mutated NSCLC cell lines were used in this study. We established drug-tolerant cells (DTCs) via 72 h treatment with osimertinib (600 nM) or afatinib (60 nM). Acquisition of drug tolerance was evaluated by growth inhibitory assay, and the molecular mechanisms of drug tolerance were analyzed by phospho-RTK array.

RESULTS

DTCs were successfully induced in PC9, HCC4006, and H1975 cells against osimertinib and in PC9 cells against afatinib. We observed that a high drug concentration was required to induce DTCs, and HCC4006 cells become tolerant when a higher dose of afatinib (>180 nM) was used. In the analysis of HCC4006 DTCs against osimertinib, we observed increased receptor-like tyrosine kinase (RYK) expression, and siRNA-mediated RYK knockdown inhibited the proliferation of DTCs.

CONCLUSIONS

These results suggest that induction of DTCs is dose-dependent, and increased RYK expression was the mechanism of drug tolerance in HCC4006 cells against osimertinib.

Transformation or Progression from Adenocarcinoma to Small Cell Lung Cancer Detected by Serially Tracking Mutations in the Blood

Background: Circulating tumour DNA (ctDNA) has emerged as a promising biomarker for monitoring non-small-cell lung cancer (NSCLC). This has enabled the monitoring of clinically actionable mutations over the course of therapy. Case presentation: We present the case of a 74-year-old female who was treated with EGFR inhibitors for NSCLC which later transformed to SCLC. The kinetics of ctDNA was monitored by measuring the EGFR Exon 19 mutant L747–A750 > P and PIK3CA E545K over the course of therapy. Stabilisation of the PIK3CA mutation was found in response to therapy, however there appeared to be increasing levels of the EGFR mutant, potentially reflective of untreated EGFR-driven disease. Conclusion: The key finding described here, revealed by mutational tracking of mutations from the blood, is that clinically actionable mutations are assessable and may demonstrate clinical utility in measuring disease burden, multiple clones and progression non-invasively for lung cancer.

The impact of EGFR exon 19 deletion subtypes on clinical outcomes in non-small cell lung cancer

Background

The study investigated the resistant pattern and clinical outcomes of epidermal growth factor receptor (EGFR) exon 19 deletion (19del) subtypes to tyrosine kinase inhibitors (TKIs) in non-small cell lung cancer (NSCLC).

Methods

Two hundred eight treatment naive NSCLC patients detected as EGFR 19del using amplification-refractory mutation system (ARMS) were included. DNA sequencing was used to detect the subtypes. Clinicopathological features as well as patients’ outcomes treated with first-line EGFR-TKIs were analyzed.

Results

Thirteen EGFR 19del subtypes were confirmed in 181 samples (87.0%). Among these, delE746_A750 was the most frequent subtype (130/181, 71.8%). delE746_A750 and deletions starting from E746 were frequently found in female (P=0.003 and P=0.013, respectively) and never smokers (P=0.002 and P=0.014, respectively) than non-delE746_A750 and deletions starting from L747 patients, respectively. T790M was more frequently occurred in delE746_A750 than non-delE746_A750 (P=0.001) and deletions starting from E746 than L747 patients (P=0.006) after first-line EGFR-TKIs resistance. Patients harboring deletions starting from L747 with insertions had significantly shorter progression-free survival (PFS) than deletions starting from L747 without insertion (8.3 vs. 15.0 m, P=0.017), or all other patients (8.3 vs. 12.6 m, P=0.027). Different 19del subtypes with T790M mutation had similar PFS when treated with osimertinib (P=0.102).

Conclusions

Patients with EGFR 19del subtypes had different clinicopathological features, and resistant pattern when treated with first-line TKIs. Patients harboring deletions starting from L747 with insertions had inferior outcomes than other subtypes.

Omega-3 Fatty Acid-Enriched Fish Oil and Selenium Combination Modulates Endoplasmic Reticulum Stress Response Elements and Reverses Acquired Gefitinib Resistance in HCC827 Lung Adenocarcinoma Cells

Non-small cell lung cancer (NSCLC)-carrying specific epidermal growth factor receptor (EGFR) mutations can be effectively treated by a tyrosine kinase inhibitor such as gefitinib. However, the inevitable development of acquired resistance leads to the eventual failure of therapy. In this study, we show the combination effect of omega-3 fatty acid-enriched fish oil (FO) and selenium (Se) on reversing the acquired gefitinib-resistance of HCC827 NSCLC cells. The gefitinib-resistant subline HCC827GR possesses lowered proapoptotic CHOP (CCAAT/enhancer-binding protein homologous protein) and elevated cytoprotective GRP78 (glucose regulated protein of a 78 kDa molecular weight) endoplasmic reticulum (ER) stress response elements, and it has elevated β-catenin and cyclooxygenase-2 (COX-2) levels. Combining FO and Se counteracts the above features of HCC827GR cells, accompanied by the suppression of their raised epithelial-to-mesenchymal transition (EMT) and cancer stem markers, such as vimentin, AXL, N-cadherin, CD133, CD44, and ABCG2. Accordingly, an FO and Se combination augments the gefitinib-mediated growth inhibition and apoptosis of HCC827GR cells, along with the enhanced activation of caspase -3, -9, and ER stress-related caspase-4. Intriguingly, gefitinib further increases the elevated ABCG2 and cancer stem-like side population in HCC827GR cells, which can also be diminished by the FO and Se combination. The results suggest the potential of combining FO and Se in relieving the acquired resistance of NSCLC patients to targeted therapy.

EGFR mutation genotypes affect efficacy and resistance mechanisms of osimertinib in T790M-positive NSCLC patients

Background

Osimertinib is a potent third-generation EGFR tyrosine kinase inhibitor (TKI) with robust activity in advanced EGFR-mutant non-small cell lung cancer (NSCLC), including those with T790M resistance mutation. However, a broad interpatient variability was observed. This study aimed to evaluate whether EGFR-mutant genotypes affect the clinical outcomes and resistance mechanisms in T790M-positive NSCLC patients receiving osimertinib therapy.

Methods

All NSCLC patients treated with osimertinib in our institute were screened. We included those with known EGFR-mutant genotypes and T790M positivity. Clinical outcomes including objective response rate (ORR), clinical benefit rate (CBR), progression-free survival (PFS), and overall survival (OS), were evaluated and compared between different EGFR genotypes. Patients with next-generation sequencing testing or tumor rebiopsy after osimertinib treatment were analyzed for resistance mechanisms.

Results

ORR, CBR, PFS, and OS were all non-significantly different among patients harboring EGFR exon 19 deletion (19Del, n=136), L858R (n=93), and uncommon mutations (n=6). However, a subset of tumors with deletion starting at E746 (ΔE746, n=98), but not non-ΔE746 tumors (n=38), had better clinical outcomes than L858R tumors (n=93). Frequencies of T790M loss and C797S acquisition after osimertinib treatment were similar between 19Del (n=56) and L858R tumors (n=33). However, compared with L858R tumors (n=33), those with 19Del ΔE746 subtype (n=40) had a higher whereas non-ΔE746 subtype (n=16) had a similar frequency of acquired C797S mutation. Combined analysis of our cohort and public cohort confirmed these findings.

Conclusions

Our findings indicate that the EGFR 19Del subtypes affect the clinical outcomes and resistance mechanisms to osimertinib in T790M-positive patients. Identifying patients with relatively worse treatment outcomes may be informative for establishing new therapies for these patients.

Association of Carbonic Anhydrase 9 Polymorphism and the Epithelial Growth Factor Receptor Mutations in Lung Adenocarcinoma Patients

Carbonic anhydrase 9 (CA9) plays a vital role in lung cancer progression. The current study explored the effect of CA9 gene polymorphisms and the epidermal growth factor receptor (EGFR) mutations on the clinicopathological characters of lung adenocarcinoma. In this study, three loci of CA9 single nucleotide polymorphism (SNP) (rs2071676 A>G, rs3829078 A>G, and rs1048638 C>A) were genotyped using the TaqMan allelic discrimination method in 193 EGFR wild type individuals and 281 EGFR mutation subjects. After adjusting for age, gender, and cigarette smoking status in logistic regression, all three CA9 SNPs illustrated a non-significant difference for the distribution between the EGFR wild type group and EGFR mutation group. Nevertheless, a significantly lower rate of CA9 SNP rs2071676 AG (adjusted odds ratio (AOR): 0.40, 95% confidence interval (CI): 0.16-0.95, p = 0.039) and AG+GG (AOR: 0.43, 95% CI: 0.18-0.98, p = 0.046) were found in the male population with L858R EGFR mutation compared to men with EGFR wild type. In addition, the CA9 SNP rs2071676 AG+GG genotype were significantly correlated to the lower tumor stage of lung adenocarcinoma in the whole study population (p = 0.044) and EGFR wild type individuals (p = 0.033). For the male population, the presence of CA9 SNP rs2071676 AG+GG genotype was also correlated to a lower tumor stage (p = 0.037) and fewer lymph node invasion (p = 0.003) in those with EGFR wild type. In conclusion, the existence of CA9 SNP rs2071676 is associated with the rate of EGFR L858R mutation in males. Furthermore, the CA9 SNP rs2071676 is correlated to lower tumor stage and lower risk for developing lymph node metastasis in lung adenocarcinoma, mainly in the EGFR wild type.

Clinical Activity of Afatinib in Patients With Non-Small-Cell Lung Cancer Harboring Uncommon EGFR Mutations: A Spanish Retrospective Multicenter Study

INTRODUCTION

Uncommon epidermal growth factor receptor (EGFR) mutations (u-EGFRm) are a heterogeneous group of molecular alterations and have also been reported as comutations with other EGFR mutations (complex mutations) in non-small-cell lung cancer (NSCLC). Afatinib has shown activity against some u-EGFRm, and we examined its efficacy in Spanish clinical practice.

PATIENTS AND METHODS

Data of 67 patients with advanced NSCLC with u-EGFRm treated with afatinib between 2012 and 2017 at 23 Spanish institutions were reviewed. u-EGFRm were analyzed as complex mutations (group A), EGFR exon 20 insertions (ins20; group B), or single mutations (group C). Efficacy was evaluated in terms of overall survival (OS) and tumor response.

RESULTS

Group A complex u-EGFRm consisted of double mutations of G719X+E709F, G719X+S768I, G719X+L861Q, L858R+T790M, L858R+S768I, L858R+S765I, del19+S768I, del19+L747S, or R776C+L861Q. No differences in clinical characteristics were found between groups A (n = 20), B (n = 23), and C (n = 24). Afatinib was administered as first-line therapy in 80% of patients. Median time of receipt of therapy was 4.2 months (range, 2.0-12.9 months). Median OS for the entire cohort was 19.9 months (95% confidence interval, 9.7, 30.1). Hazard ratios for OS were 0.26 (95% confidence interval, 0.10, 0.71; P = .008) and 0.40 (95% confidence interval, 0.17, 0.95; P = .037) for groups A and C compared to B, respectively. Response was significantly higher in groups A (70%) and C (54%) compared to B (13%; pairwise comparison P < .001 and .008, respectively).

CONCLUSION

In clinical practice, afatinib was active in patients with u-EGFRm NSCLC, particularly in complex and single mutations. Further strategies are needed for patients with ins20, a subgroup u-EGFRm with a lower clinical benefit with afatinib.

Determining the appropriate treatment for different EGFR mutations in non-small cell lung cancer patients

Introduction: Epidermal growth factor receptor (EGFR) mutations occur in a significant fraction of non-small cell lung cancer (NSCLC) patients. Most common activating mutations are in-frame deletion in exon 19 and point mutation in exon 21. EGFR tyrosine kinase inhibitors (TKIs) represent standard of care of EGFR mutated patients bearing common mutations. Therapy for individuals carrying uncommon mutations, such as G719X, L861Q, S768I, is less defined and few options exist for individuals harboring EGFR exon 20 mutations. In all mutated patients, drug resistance remains the most critical clinical problem and new agents and strategies are under investigation.Areas covered: We have reviewed the current status of NSCLC EGFR mutated treatment by analyzing data from preclinical studies, clinical prospective and retrospective trials in order to analyze current and future options for patients harboring different EGFR mutations.Expert opinion: At the present time, available data demonstrated that osimertinib is the best EGFR-TKI for front-line therapy. Other agents, such as dacomitinib, and new drug combinations, such as regimens including anti-angiogenic agents or chemotherapy, demonstrated to significantly prolong progression-free survival or overall survival, representing potential alternative to osimertinib. Many questions remain opened, including best drug sequencing and needing of new therapeutic approaches extending patient survival and cure rate.

The significance of epidermal growth factor receptor uncommon mutations in non-small cell lung cancer: A systematic review and critical appraisal

Uncommon epidermal growth factor receptor (EGFR) mutations collectively account for 10% of EGFR mutations, harboring heterogeneous molecular alterations within exons 18-21 with clinically variable responses to EGFR tyrosine kinase inhibitors (TKIs) in advanced Non-Small Cell Lung Cancer (NSCLC) patients. In addition, with the introduction of different NGS gene approach an improvement of EGFR mutations detection was reported. Today, no specific studies have prospectively evaluated uncommon sensitizing mutations in detail and no firm standard of care has been established in the first-line setting. The aim of this comprehensive review is to critically consider the clinical role of uncommon EGFR mutations highlighting the results of several in vitro and in vivo studies, which singly evaluated the sensitivity of uncommon mutations to currently European of Medicines Agency (EMA)-approved EGFR TKIs in cell lines, xenograft models and humans, in order to obtain a practical guide for refining the clinical decision-making process.