In vitro modeling to determine mutation specificity of EGFR tyrosine kinase inhibitors against clinically relevant EGFR mutants in non-small-cell lung cancer

Novel therapeutic strategies for rare mutations in non-small cell lung cancer

Lung cancer is still the leading cause of cancer-related mortality. Over the past two decades, the management of non-small cell lung cancer (NSCLC) has undergone a significant revolution. Since the first identification of activating mutations in the epidermal growth factor receptor (EGFR) gene in 2004, several genetic aberrations, such as anaplastic lymphoma kinase rearrangements (ALK), neurotrophic tropomyosin receptor kinase (NTRK) and hepatocyte growth factor receptor (MET), have been found. With the development of gene sequencing technology, the development of targeted drugs for rare mutations, such as multikinase inhibitors, has provided new strategies for treating lung cancer patients with rare mutations. Patients who harbor this type of oncologic driver might acquire a greater survival benefit from the use of targeted therapy than from the use of chemotherapy and immunotherapy. To date, more new agents and regimens can achieve satisfactory results in patients with NSCLC. In this review, we focus on recent advances and highlight the new approval of molecular targeted therapy for NSCLC patients with rare oncologic drivers.

Current management of uncommon EGFR mutations in non-small cell lung cancer

Epidermal growth factor receptor (EGFR) mutations are frequently implicated in non-small cell lung cancer (NSCLC). Though these typically involve exon 19 in-frame deletions or L858R mutations in exon 21, uncommon EGFR mutations comprise 10-15 % of all EGFR mutations. These most frequently include G719X mutations in exon 18, L861Q mutations in exon 21, S768I mutations in exon 20, and in-frame insertions and/or duplications in exon 20. It is crucial to understand these distinct variants and their specific responses to active treatment options to optimize care. In this review, we discuss these uncommon mutations in depth and dissect the current literature regarding their treatment outcomes and subsequent evidence-based management guidelines.

Tumor Organoids: The Era of Personalized Medicine

The strategies of future medicine are aimed to modernize and integrate quality approaches including early molecular-genetic profiling, identification of new therapeutic targets and adapting design for clinical trials, personalized drug screening (PDS) to help predict and individualize patient treatment regimens. In the past decade, organoid models have emerged as an innovative in vitro platform with the potential to realize the concept of patient-centered medicine. Organoids are spatially restricted three-dimensional clusters of cells ex vivo that self-organize into complex functional structures through genetically programmed determination, which is crucial for reconstructing the architecture of the primary tissue and organs. Currently, there are several strategies to create three-dimensional (3D) tumor systems using (i) surgically resected patient tissue (PDTOs, patient-derived tumor organoids) or (ii) single tumor cells circulating in the patient's blood. Successful application of 3D tumor models obtained by co-culturing autologous tumor organoids (PDTOs) and peripheral blood lymphocytes have been demonstrated in a number of studies. Such models simulate a 3D tumor architecture in vivo and contain all cell types characteristic of this tissue, including immune system cells and stem cells. Components of the tumor microenvironment, such as fibroblasts and immune system cells, affect tumor growth and its drug resistance. In this review, we analyzed the evolution of tumor models from two-dimensional (2D) cell cultures and laboratory animals to 3D tissue-specific tumor organoids, their significance in identifying mechanisms of antitumor response and drug resistance, and use of these models in drug screening and development of precision methods in cancer treatment.

EGFR exon20 insertion mutations in non-small cell lung cancer: Clinical implications and recent advances in targeted therapies

The advent of targeted therapies for oncogenic mutations has led to a major paradigm shift in the management of non-small cell lung cancer (NSCLC). Molecular targets, such as epidermal growth factor receptor (EGFR)-activating mutations in the region of exons 18 through 21 are the most common oncogenic driver in NSCLC. Classical activating mutations, such as in-frame deletions in exon 19 and point mutations in exon 21 (L858R), are strong predictors for good clinical response to the approved EGFR-tyrosine kinase inhibitors (EGFR-TKIs). However, low frequency mutations occurring within exon 20 (ex20ins) have poorer responses to first/second generation EGFR-TKIs. Moreover, patients with NSCLC harboring EGFR ex20ins are known to have poorer prognosis than those with other EGFR-TKI sensitive mutations, leading to unmet clinical need of novel specific therapeutic options. Rapid changes in molecular diagnostics identifying specific causes have hastened the translation of diagnostic recommendations into clinical practice. Emergence of treatment strategies targeting EGFR ex20ins, such as newer EGFR-TKIs with increased specificity and novel approaches using bispecific monoclonal antibodies, may hold promising therapeutic options in the near future. In this review, we describe the structural, molecular characteristics, and detection strategies of EGFR ex20ins mutations and summarize the latest clinical data on approved treatments and emerging therapies for patients with NSCLC harboring EGFR ex20ins mutations. Further, we will discuss the response heterogeneity of ex20ins mutations to new drugs and acquired drug resistance mechanisms.

Structural Mechanism and Inhibitors Targeting EGFR Exon 20 Insertion (Ex20ins) Mutations

Epidermal growth factor receptor (EGFR) targeted therapy is one of the most important and effective strategies to combat EGFR mutant nonsmall-cell lung cancer (NSCLC). However, a substantial number of patients bearing EGFR exon 20 insertion (Ex20ins) mutations respond poorly to common EGFR targeted therapies. This clinical need remained unmet until recently, when the EGFR Ex20ins mutation inhibitor mobocertinib was approved by the FDA. Despite this progress, the structural mechanisms of EGFR Ex20ins mutation resistance and characterization of inhibitor binding modes have not been systematically summarized. Herein, we analyze the structural mechanisms for ligand binding and resistance and summarize recent developments for the reported inhibitors of EGFR Ex20ins mutations. Furthermore, this Perspective aims to provide insights for the design of the next generation of EGFR Ex20ins inhibitors.

EGFR exon 20 insertion mutations and ERBB2 mutations in lung cancer: a narrative review on approved targeted therapies from oral kinase inhibitors to antibody-drug conjugates

Background and Objective

This review will provide an overview of EGFR and ERBB2 mutations in non-small-cell lung cancer (NSCLC) with a focus on recent clinical approvals.

Methods

We obtained data from the literature in accordance with narrative review reporting guidelines.

Key Content and Findings

EGFR mutations are present in up to 15-20% of all NSCLCs; amongst these, 10% correspond to kinase domain insertions in exon 20. Structurally similar, ERBB2 (HER2) mutations occurs in 1-4% of NSCLCs, mostly consisting of insertions or point mutations. The majority of EGFR exon 20 insertions occur within the loop following the regulatory C-helix and activate the kinase domain of EGFR without generating a therapeutic window to gefitinib, erlotinib, afatinib, dacomitinib or osimertinib. Mobocertinib represents a novel class of covalent EGFR inhibitors with a modest therapeutic window to these mutants and induces anti-tumor responses in a portion of patients [at 160 mg/day: response rate of <30% with duration of response (DoR) >17 months and progression-free survival (PFS) of >7 months] albeit with mucocutaneous and gastrointestinal toxicities. The bi-specific EGFR-MET antibody amivantamab-vmjw has modest but broad preclinical activity in EGFR-driven cancers and specifically for EGFR exon 20 insertion-mutated NSCLC has response rates <40% and PFS of <8.5 months at the cost of both infusion-related plus on-target toxicities. Both drugs were approved in 2021. The clinical development of kinase inhibitors for ERBB2-mutated NSCLC has been thwarted by mucocutaneous/gastrointestinal toxicities that preclude a pathway for drug approval, as the case of poziotinib. However, the activation of ERBB2 has allowed for repurposing of antibody-drug conjugates (ADCs) that target ERBB2 with cytotoxic payloads. The FDA approved fam-trastuzumab deruxtecan-nxki in 2022 for NSCLC based on response rate of >55%, DoR >9 months, PFS >8 months and manageable adverse events (including cytopenias, nausea and less commonly pneumonitis). Other therapies in clinical development include sunvozertinib and zipalertinib, among others. In addition, traditional cytotoxic chemotherapy has some activity in these tumors.

Conclusions

The approvals of mobocertinib, amivantamab, and trastuzumab deruxtecan represent the first examples of precision oncology for EGFR exon 20 insertion-mutated and ERBB2-mutated NSCLCs.

The complexity of EGFR exon 19 deletion and L858R mutant cells as assessed by proteomics, transcriptomics, and metabolomics

Most lung adenocarcinoma-associated EGFR tyrosine kinase mutations are either an exon 19 deletion (19Del) or L858R point mutation in exon 21. Although patients whose tumors contain either of these mutations exhibit increased sensitivity to tyrosine kinase inhibitors, progression-free and overall survival appear to be longer in patients with 19Del than in those with L858R. In mutant-transfected Ba/F3 cells, 19Del and L858R were compared by multi-omics analyses including proteomics, transcriptomics, and metabolomics. Proteome analysis identified increased plastin-2, TKT, PDIA5, and ENO1 expression in L858R cells, and increased EEF1G expression in 19Del cells. RNA sequencing showed significant differences between 19Del and L858R cells in 112 genes. Metabolome analysis showed that amino acids, adenylate, guanylate, NADPH, lactic acid, pyruvic acid glucose 6-phosphate, and ribose 5-phosphate were significantly different between the two mutant cells. Because GSH was increased with L858R, we combined osimertinib with the GSH inhibitor buthionine sulfoximine in L858R cells and observed synergistic effects. The complexity of EGFR 19Del and L858R mutant cells was demonstrated by proteomics, transcriptomics, and metabolomics analyses. Therapeutic strategies for lung cancer with different EGFR mutations could be considered because of their different metabolic phenotypes.

[Advances in the Treatment of EGFR Exon 20ins Mutant NSCLC]

Lung cancer has become one of the most dangerous cancers to human health and the mortality rate is the highest among all the causes of cancer death. Non-small cell lung cancer (NSCLC) accounts for about 80%-85% of lung cancer. Chemotherapy is the main treatment for advanced NSCLC, but the 5-year survival rate is low. Epidermal growth factor receptor (EGFR) mutations are the most common driver mutations in lung cancer, but EGFR exon 20 insertions (EGFR ex20ins) mutation belongs to one of the rare mutations, accounting for about 4%-10% of overall EGFR mutations, thus around 1.8% of advanced NSCLC patients. In recent years, targeted therapies represented by EGFR tyrosine kinase inhibitors (TKIs) have become an important treatment option for patients with advanced NSCLC, however, NSCLC patients with EGFR ex20ins mutation are not sensitive to most of EGFR-TKIs treatments. Currently, some of the targeted drugs for EGFR ex20ins mutation have achieved significant efficacy, while some of them are still under clinical investigation. In this article, we will describe various treatment methods for EGFR ex20ins mutation and their efficacy.
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Small Molecule EGFR Inhibitors as Anti-Cancer Agents: Discovery, Mechanisms of Action, and Opportunities

Epidermal growth factor receptors (EGFRs) are a class of receptor tyrosine kinase that are also called ErbB1 and HER1. EGFR tyrosine kinase activity inhibition is considered a promising therapeutic strategy for the treatment of cancer. Many small-molecule inhibitors of EGFR tyrosine kinase (EGFR-TK), from medicinally privileged molecules to commercial drugs, have been overviewed. Particular attention has been paid to the structure of the molecule and its mechanism of action if reported. Subsequent classification of the molecules under discussion has been carried out. Both natural and synthetic and reversible and irreversible EGFR-tyrosine kinase inhibitors have been discussed. Various types of cancers that are caused by overexpression of the EGFR gene, their possible molecular origins, and their natures have also been counted in this article. Because the EGFR signaling pathway controls the proliferation, growth, survival, and differentiation of cells, and the mutated EGFR gene overproduces EGFR protein, which ultimately causes several types of cancer, proper understanding of the molecular dynamics between the protein structure and its inhibitors will lead to more effective and selective EGFR-TKIs, which in turn will be able to save more lives in the battle against cancer.

Advances in the management of non-small-cell lung cancer harbouring EGFR exon 20 insertion mutations

Epidermal growth factor receptor (EGFR) mutation is one of the key oncogenic mutations in non-small-cell lung cancer with adenocarcinoma histology. Exon 19 deletions and exon 21 L858R substitutions account for 90%, while EGFR exon 20 insertions constitute 4-10% of EGFR mutations and are the third most prevalent activating EGFR mutations. EGFR exon 20 insertions are associated with decreased sensitivity to EGFR tyrosine kinase inhibitors and, until recently, effective targeted therapy against these tumours remained an unmet clinical need and chemotherapy was the only treatment of choice available. The approval of amivantamab and mobocertinib for patients who have progressed after chemotherapy represents an important step forward in the management of these patients. Here in this review, we summarize the epidemiology, structure and the tumour microenvironment of EGFR exon 20 insertion and also review the systemic treatments, including targeted therapies and ongoing clinical trials in EGFR exon 20 insertion mutations, as well as detection methods for EGFR exon 20 insertion. Lastly, resistant mechanisms and future directions are addressed.

New Targeted Therapy for Non-Small Cell Lung Cancer

Lung cancer ranks first in cancer mortality in Korea and cancer incidence in Korean men. More than half of Korean lung cancer patients undergo chemotherapy, including adjuvant therapy. Cytotoxic agents, targeted therapy, and immune checkpoint inhibitors are used in chemotherapy according to the biopsy and genetic test results. Among chemotherapy, the one that has developed rapidly is targeted therapy. The National Comprehensive Cancer Network (NCCN) guidelines have been updated recently for targeted therapy of multiple gene mutations, and targeted therapy is used not only for chemotherapy but also for adjuvant therapy. While previously targeted therapies have been developed for common genetic mutations, recently targeted therapies have been developed to overcome uncommon mutations or drug resistance that have occurred since previous targeted therapy. Therefore, this study describes recent, rapidly developing targeted therapies.

Non-small Cell Lung Cancer with EGFR or HER2 Exon 20 Insertion Mutations: Diagnosis and Treatment Options

Molecular testing is performed upon diagnosis of non-small cell lung cancer (NSCLC) because of the large success of targeted therapies for oncogenic mutations. Epidermal growth factor receptor (EGFR) mutations are the most commonly identified mutation in NSCLC, and EGFR exon 20 insertion mutations (exon20ins) are the third most common mutation in EGFR following EGFR exon 19 deletions and exon 21 L858R mutations. EGFR exon20ins have regularly demonstrated resistance to classical EGFR inhibition. Two treatments-mobocertinib and amivantamab-have recently been the first drugs to be approved by the US Food and Drug Administration (FDA) for treatment of lung cancers with these mutations following platinum-based therapy. Research surrounding these two drugs demonstrates strong efficacy, but with an intense array of side effects. Another targetable driver mutation is the human epidermal growth factor receptor 2 (HER2) exon20ins, representing approximately 2-3% of NSCLC patients. This mutation has been heavily studied in vitro as well as clinically, and trastuzumab deruxtecan was just recently granted accelerated FDA approval based on the high efficacy demonstrated in the Destiny-Lung01 study. However, similar to their EGFR counterparts, HER2 inhibitors also have evidence of toxicity in clinical studies. In this paper, we discuss the limited response of EGFR and HER2 exon20ins to a wide range of standard treatment regimens, such as platinum-based chemotherapy and classic EGFR tyrosine kinase inhibitors, as well as immunotherapy. We also review recently approved and upcoming targeted therapeutic options, considering what research is presently being done regarding efficacy and the reduction of side effects, as well as the agents' risks and benefits for incorporation into an approved treatment regimen.

Discovery of mobocertinib, a new irreversible tyrosine kinase inhibitor indicated for the treatment of non-small-cell lung cancer harboring EGFR exon 20 insertion mutations

Epidermal growth factor receptor (EGFR) is essential for normal cellular functions. Mutations of EGFR’s kinase domain can cause dysregulation leading to non-small cell lung cancer (NSCLC). Exon 20 insertion (ex20ins) mutations in EGFR are one of the leading contributors to oncogenesis and confer insensitivity to most available therapeutics. Mobocertinib is a novel tyrosine kinase inhibitor (TKI) recently approved by the US FDA as a first-in-class small molecule therapeutic for EGFR ex20ins-positive NSCLC. When compared to osimertinib, a TKI indicated for the treatment of EGFR T790M-positive NSCLC, mobocertinib differs only by the presence of an additional C5-carboxylate isopropyl ester group on the middle pyrimidine core. Together with the acrylamide side chain that is responsible for irreversible inhibition, this additional C5-substituent affords mobocertinib high anticancer potency and specificity to EGFR ex20ins-positive lung cancer that is resistant to other EGFR TKIs. This review article provides an overview of the discovery of mobocertinib from osimertinib including their structure-activity relationships, mechanisms of action, preclinical pharmacology, pharmacokinetics, and clinical applications. The discovery and use of mobocertinib and other EGFR TKIs demonstrate the power of structure-based drug design and promising therapeutic outcomes of using precision medicine approaches in the management of molecularly defined tumors.

Exposure-Response Analysis of Osimertinib in EGFR Mutation Positive Non-Small Cell Lung Cancer Patients in a Real-Life Setting

BACKGROUND

Osimertinib, an irreversible inhibitor of the epidermal growth factor receptor (EGFR) is an important drug in the treatment of EGFR-mutation positive non-small cell lung cancer (NSCLC). Clinical trials with osimertinib could not demonstrate an exposure-efficacy relationship, while a relationship between exposure and toxicity has been found. In this study, we report the exposure-response relationships of osimertinib in a real-life setting.

METHODS

A retrospective observational cohort study was performed, including patients receiving 40 - 80 mg osimertinib as ≥ 2 line therapy and from whom pharmacokinetic samples were collected during routine care. Trough plasma concentrations (C_min,pred) were estimated and used as a measure of osimertinib exposure. A previously defined exploratory pharmacokinetic threshold of 166 µg/L was taken to explore the exposure-efficacy relationship.

RESULTS

A total of 145 patients and 513 osimertinib plasma concentration samples were included. Median progression free survival (PFS) was 13.3 (95% confidence interval (CI):10.3 - 19.1) months and 9.3 (95% CI: 7.2 - 11.1) months for patients with C_min,pred < 166 µg/L and C_min,pred ≥ 166 µg/L, respectively (p = 0.03). In the multivariate analysis, a C_min,pred < 166 µg/L resulted in a non-statistically significant hazard ratio of 1.10 (95% CI: 0.60 - 2.01; p = 77). Presence of a EGFR driver-mutation other than the exon 19 del or L858R mutations, led to a shorter PFS with a hazard ratio of 2.89 (95% CI: 1.18 - 7.08; p = 0.02). No relationship between exposure and toxicity was observed (p = 0.91).

CONCLUSION

In our real-life cohort, no exposure-response relationship was observed for osimertinib in the current dosing scheme. The feasibility of a standard lower fixed dosing of osimertinib in clinical practice should be studied prospectively.

Lung Cancer Organoids: The Rough Path to Personalized Medicine

Simple Summary

Lung cancer is very difficult to cure, especially when it has spread to other parts of the body. One of the main reasons that delay the identification of effective therapies is the complexity of lung cancer cells, which can be very different among individual patients. Organoids are small aggregates of tumor cells that are generated from lung tumors and used in cancer research laboratories to study the features of tumor cells. Organoids have unique properties, as they reproduce many characteristics of the tumor derived from each specific patient. Due to their capacity to reproduce individual tumor features in the laboratory setting, organoids are an excellent system to study lung cancer and to identify functional therapies. This review summarizes the challenges encountered by researchers in the field of lung cancer organoids and describes how the advances in organoid technology may allow the future development of individualized therapies for lung cancer patients.

Abstract

Lung cancer is the leading cause of cancer death worldwide. Despite significant advances in research and therapy, a dismal 5-year survival rate of only 10–20% urges the development of reliable preclinical models and effective therapeutic tools. Lung cancer is characterized by a high degree of heterogeneity in its histology, a genomic landscape, and response to therapies that has been traditionally difficult to reproduce in preclinical models. However, the advent of three-dimensional culture technologies has opened new perspectives to recapitulate in vitro individualized tumor features and to anticipate treatment efficacy. The generation of lung cancer organoids (LCOs) has encountered greater challenges as compared to organoids derived from other tumors. In the last two years, many efforts have been dedicated to optimizing LCO-based platforms, resulting in improved rates of LCO production, purity, culture timing, and long-term expansion. However, due to the complexity of lung cancer, further advances are required in order to meet clinical needs. Here, we discuss the evolution of LCO technology and the use of LCOs in basic and translational lung cancer research. Although the field of LCOs is still in its infancy, its prospective development will likely lead to new strategies for drug testing and biomarker identification, thus allowing a more personalized therapeutic approach for lung cancer patients.

Case Report: Two Patients With EGFR Exon 20 Insertion Mutanted Non-Small Cell Lung Cancer Precision Treatment Using Patient-Derived Xenografts in Zebrafish Embryos

Background

Epidermal growth factor receptor (EGFR) exon 20 insertion mutations are uncommon EGFR mutations and generally resistant to first- and second-generation EGFR-tyrosine kinase inhibitors (TKIs). In precision oncology, treatment regimens are tested for improving the clinical outcomes. Zebrafish embryo tumor transplant models are used in cancer research.

Methods

We report two Chinese females who were diagnosed with stage IV lung adenocarcinoma and shown to harbor EGFR exon 20 insertion mutations by next-generation sequencing (NGS). Then, we established lung cancer patient-derived xenografts using a zebrafish model. The tumor cells were isolated from the patient. For case one, tumor cells were collected from lymph node biopsy, while the tumor cells were obtained from the pleural effusion. Zebrafish were inoculated with tumor cells and placed in the culture medium containing the third-generation EGFR-TKI, osimertinib. Fluorescence microscope photographs were used to record the red fluorescence area, which represented the proliferation and migration of tumor cells in the zebrafish.

Results

Case one was diagnosed with lung adenocarcinoma (cT4N3M1b, stage IVB) and had an EGFR exon 20 mutation (p. N771delinsHH [abundance 14.08%]). Tumor cell proliferation and migration were significantly reduced in the osimertinib group compared with the control group. The patient received first-line osimertinib (160 mg). According to RECIST v1.1, she achieved a partial response. Case two had stage IVA lung adenocarcinoma with a pleural effusion. The pleural effusion sample was selected to obtain tumor cells for injection, and the zebrafish lung cancer model was established. The proliferation of tumor cells in the osimertinib group was significantly reduced compared to the control group. The migration of tumor cells was not significantly reduced compared to the control group. The patient also received first-line osimertinib (160 mg). The lung lesions were stable, but the pleural effusion was poorly controlled.

Conclusion

Our study demonstrates the applicability of a zebrafish embryos model as an innovative platform to targeted drug testing. More precise methods are needed to select treatment options in the future.

Physiologically Based Pharmacokinetic (PBPK) Modeling to Predict PET Image Quality of Three Generations EGFR TKI in Advanced-Stage NSCLC Patients

Introduction: Epidermal growth factor receptor (EGFR) mutated NSCLC is best treated using an EGFR tyrosine kinase inhibitor (TKI). The presence and accessibility of EGFR overexpression and mutation in NSCLC can be determined using radiolabeled EGFR TKI PET/CT. However, recent research has shown a significant difference between image qualities (i.e., tumor-to-lung contrast) in three generation EGFR TKIs: ¹¹C-erlotinib, ¹⁸F-afatinib and ¹¹C-osimertinib. In this research we aim to develop a physiological pharmacokinetic (PBPK)-model to predict tumor-to-lung contrast and as a secondary outcome the uptake of healthy tissue of the three tracers. Methods: Relevant physicochemical and drug specific properties (e.g., pKa, lipophilicity, target binding) for each TKI were collected and applied in established base PBPK models. Key hallmarks of NSCLC include: immune tumor deprivation, unaltered tumor perfusion and an acidic tumor environment. Model accuracy was demonstrated by calculating the prediction error (PE) between predicted tissue-to-blood ratios (TBR) and measured PET-image-derived TBR. Sensitivity analysis was performed by excluding each key component and comparing the PE with the final mechanistical PBPK model predictions. Results: The developed PBPK models were able to predict tumor-to-lung contrast for all EGFR-TKIs within threefold of observed PET image ratios (PE tumor-to-lung ratio of −90%, +44% and −6.3% for erlotinib, afatinib and osimertinib, respectively). Furthermore, the models depicted agreeable whole-body distribution, showing high tissue distribution for osimertinib and afatinib and low tissue distribution at high blood concentrations for erlotinib (mean PE, of −10.5%, range −158%–+190%, for all tissues). Conclusion: The developed PBPK models adequately predicted the image quality of afatinib and osimertinib and erlotinib. Some deviations in predicted whole-body TBR lead to new hypotheses, such as increased affinity for mutated EGFR and active influx transport (erlotinib into excreting tissues) or active efflux (afatinib from brain), which is currently unaccounted for. In the future, PBPK models may be used to predict the image quality of new tracers.

High dose osimertinib in patients with advanced stage EGFR exon 20 mutation-positive NSCLC: Results from the phase 2 multicenter POSITION20 trial

INTRODUCTION

Patients with life-threatening advanced non-small cell lung cancer (NSCLC) who harbor an exon 20 deletion and/or insertion mutation (EGFRex20 + ) have limited effective treatment options. The high dose 3rd generation tyrosine kinase inhibitor (TKI) osimertinib shows promising in vitro activity in EGFRex20 + NSCLC tumors.

METHODS

The POSITION20 is a single arm phase II, multicenter study investigating 160 mg osimertinib in patients with EGFRex20+, T790M negative NSCLC. We allowed patients to be treatment naïve and to have asymptomatic brain metastases. The primary endpoint was overall response rate (ORR). Secondary outcomes were duration of response (DoR), progression free survival (PFS), overall survival (OS), and treatment related adverse events (trAEs).

RESULTS

From June 2018 to October 2021, 25 patients were enrolled across five centers in the Netherlands. The median age was 70 years (range, 47-87), 20 patients (80%) were women, and the median number of previous lines of therapy was 1 (range, 0-3). The exon 20 mutations were clustered between A763 and L777. The most common exon 20 mutations were p.(N771_H773dup) (n = 3) and p.(A767_V769dup) (n = 3). The ORR was 28% (95% CI, 12-49%), including seven partial responses, with a median DoR of 5.3 months (range, 2.7-27.6). The median PFS was 6.8 months (95% CI, 4.6-9.1) and the median OS was 15.2 months (95% CI, 14.3-16.0). The most common trAEs were diarrhea (72%), dry skin (44%), and fatigue (44%). The primary reason for discontinuation was progressive disease in 14 patients (56%).

CONCLUSION

The POSITION20 study showed modest antitumor activity in patients with EGFRex20 + NSCLC treated with 160 mg osimertinib, with a confirmed ORR of 28% and acceptable toxicity.

Development and Optimization of Osimertinib-loaded Biodegradable Polymeric Nanoparticles Enhance In-vitro Cytotoxicity in Mutant EGFR NSCLC Cell Models and In-vivo Tumor Reduction in H1975 Xenograft Mice Models

Osimertinib (OMB), a third-generation EGFR inhibitor, specifically and irreversibly inhibits EGFR_T790M mutant form. Nevertheless, its clinical use is limited due to poor solubility, low absorption, and oral bioavailability. To overcome the low therapeutic capabilities of the free drug, we developed OMB-loaded PCL or CHS nanoparticles and characterized them. Among fifteen devised nanoparticle formulations (Npfs), OMB-PCL-f3, f9, and OMB-CHS-f3 showed great characteristics such as particle size (ranges from 101.3 ± 8.2 to 119.7 ± 10.4 nm), zeta potential (-36.4 ± 3.2 to -31.7 ± 3.9 mV), and polydispersity index (0.227 ± 0.037 to 0.261 ± 0.025). The % entrapment (91.25 ± 5.84 to 95.25 ± 5.88) and drug loading (29.64 ± 2.38 to 33.59 ± 2.36) indicated the formulation optimization. OMB-CHS-f3 demonstrated long-term in-vitro release, with a % cumulative OMB release of 99.99 ± 2.67 within 24 h, and the cytotoxicity of OMB-CHS-f3 showed 2.6- and 2.4-fold superior activity in mutant EGFR harboring H1975 and PC-9 cells, respectively, compared to plain OMB. Quantitative assessment of OMB cellular uptake from OMB-CHS-f3 showed superior drug accumulation of 81.59 ± 5.8% and 77.31 ± 4.6% in H1975 and PC-9 cells which was more than OMB-CHS-f9 and plain OMB. Flow cytometric cell cycle analysis revealed that OMB-CHS-f3 triggered G2/M phase arrest greater than OMB-PCL-f9 and plain OMB. In vivo, OMB-CHS-f3 Npf treatment reduced tumor size and body weight gain compared to Tagrisso treatment (p < 0.05). These findings showed that chitosan-coated OMB Npfs might improve outcomes by overcoming complications, including resistance and disease recurrence in NSCLC patients.

Investigation of molecular mechanism leading to gefitinib and osimertinib resistance against EGFR tyrosine kinase: molecular dynamics and binding free energy calculation

Tyrosine kinase (TK) is an important protein responsible for phosphorylation of variety of proteins that helps in signal transduction process in transferring signal to regulate various physiological and biochemical processes. Drugs inhibiting signal transduction pathways can be a very rational approach to inhibit cellular physiological and biochemical process. Tyrosine kinase inhibitors are a wide family of drugs that have been used successfully in cancer chemotherapy. Certain mutations around the catalytic cleft may cause conformational changes at binding site and leads to decrease in inhibitor sensitivity to TK mutants. EGFR^T790M mutation is the first recognized acquired resistance after tyrosine kinase inhibitor therapy that leads to resistant to first generation TKI in about 50% of non-small cell lung carcinoma patients. Third generation EGFR-TKIs bind irreversibly to the C797, which is present in the ATP-binding pocket. The present work provides a molecular mechanism for understanding the Gefitinib and Osimertinib sensitivities with the EGFR^WILD, EGFR^L858R, EGFR^T790M, EGFR^T790M+C797S mutants using molecular modelling techniques. Changes in response against Gefitinib and Osimertinib were observed with the change of amino acids at the tyrosine kinase domain of EGFR^WILD and its mutants (EGFR^L858R, EGFR^T790M, EGFR^T790M+C797S). RMSD, RMSF and binding energies calculation well correlates with the change in clinical observation.Communicated by Ramaswamy H. Sarma.

Analysis to determine the effect of mutations on binding to small chemical molecules

In this paper, the authors present and describe, in detail, an original software-implemented numerical methodology used to determine the effect of mutations on binding to small chemical molecules, on the example of gefitinib, AMPPNP, CO-1686, ASP8273, erlotinib binding with EGFR protein, and imatinib binding with PPARgamma. Furthermore, the developed numerical approach makes it possible to determine the stability of a molecular complex, which consists of a protein and a small chemical molecule. The description of the software package that implements the presented algorithm is given in the website: https://binomlabs.com/ .

EGFR exon 20 insertion mutations in advanced non-small-cell lung cancer: current status and perspectives

Platinum-based chemotherapy was previously the first-choice treatment for lung cancer. The discovery of epidermal growth factor receptor (EGFR) gene mutations and the development of EGFR tyrosine kinase inhibitors (TKIs) marked the beginning of the targeted therapy era for non-small-cell lung cancer (NSCLC). Thirty percent of NSCLC patients carry EGFR gene mutations. For these advanced NSCLC patients, EGFR-TKIs are currently preferred for their superior activity and survival benefits over platinum-based chemotherapy. However, therapeutic efficacy is quite different in patients with EGFR exon 20 insertion (ex20ins) mutations versus common mutations. Patients with ex20ins mutations are insensitive to EGFR-TKIs and have poor prognosis. Some drugs targeting EGFR ex20ins mutations have been approved. Here, we systematically reviewed the recent clinical research of and treatments used for EGFR ex20ins mutations, summarized the latest data on emerging therapies, and discussed future prospects and treatments.

EGFR signaling pathway as therapeutic target in human cancers

Epidermal Growth Factor Receptor (EGFR) enacts major roles in the maintenance of epithelial tissues. However, when EGFR signaling is altered, it becomes the grand orchestrator of epithelial transformation, and hence one of the most world-wide studied tyrosine kinase receptors involved in neoplasia, in several tissues. In the last decades, EGFR-targeted therapies shaped the new era of precision-oncology. Despite major advances, the dream of converting solid tumors into a chronic disease is still unfulfilled, and long-term remission eludes us. Studies investigating the function of this protein in solid malignancies have revealed numerous ways how tumor cells dysregulate EGFR function. Starting from preclinical models (cell lines, organoids, murine models) and validating in clinical specimens, EGFR-related oncogenic pathways, mechanisms of resistance, and novel avenues to inhibit tumor growth and metastatic spread enriching the therapeutic portfolios, were identified. Focusing on non-small cell lung cancer (NSCLC), where EGFR mutations are major players in the adenocarcinoma subtype, we will go over the most relevant discoveries that led us to understand EGFR and beyond, and highlight how they revolutionized cancer treatment by expanding the therapeutic arsenal at our disposal.

Relationship between Biodistribution and Tracer Kinetics of 11C-Erlotinib, 18F-Afatinib and 11C-Osimertinib and Image Quality Evaluation Using Pharmacokinetic/Pharmacodynamic Analysis in Advanced Stage Non-Small Cell Lung Cancer Patients

Background: Patients with non-small cell lung cancer (NSCLC) driven by activating epidermal growth factor receptor (EGFR) mutations are best treated with therapies targeting EGFR, i.e., tyrosine kinase inhibitors (TKI). Radiolabeled EGFR-TKI and PET have been investigated to study EGFR-TKI kinetics and its potential role as biomarker of response in NSCLC patients with EGFR mutations (EGFRm). In this study we aimed to compare the biodistribution and kinetics of three different EGFR-TKI, i.e., 11C-erlotinib, 18F-afatinib and 11C-osimertinib. Methods: Data of three prospective studies and 1 ongoing study were re-analysed; data from thirteen patients (EGFRm) were included for 11C-erlotinib, seven patients for 18F-afatinib (EGFRm and EGFR wild type) and four patients for 11C-osimertinib (EGFRm). From dynamic and static scans, SUV and tumor-to-blood (TBR) values were derived for tumor, lung, spleen, liver, vertebra and, if possible, brain tissue. AUC values were calculated using dynamic time-activity-curves. Parent fraction, plasma-to-blood ratio and SUV values were derived from arterial blood data. Tumor-to-lung contrast was calculated, as well as (background) noise to assess image quality. Results: 11C-osimertinib showed the highest SUV and TBR (AUC) values in nearly all tissues. Spleen uptake was notably high for 11C-osimertinib and to a lesser extent for 18F-afatinib. For EGFRm, 11C-erlotinib and 18F-afatinib demonstrated the highest tumor-to-lung contrast, compared to an inverse contrast observed for 11C-osimertinib. Tumor-to-lung contrast and spleen uptake of the three TKI ranked accordingly to the expected lysosomal sequestration. Conclusion: Comparison of biodistribution and tracer kinetics showed that 11C-erlotinib and 18F-afatinib demonstrated the highest tumor-to-background contrast in EGFRm positive tumors. Image quality, based on contrast and noise analysis, was superior for 11C-erlotinib and 18F-afatinib (EGFRm) scans compared to 11C-osimertinib and 18F-afatinib (EGFR wild type) scans.

Epithelial-mesenchymal transition and H2O2 signaling - a driver of disease progression and a vulnerability in cancers

Mutation-selective drugs constitute a great advancement in personalized anticancer treatment with increased quality of life and overall survival in cancers. However, the high adaptability and evasiveness of cancers can lead to disease progression and the development of drug resistance, which cause recurrence and metastasis. A common characteristic in advanced neoplastic cancers is the epithelial-mesenchymal transition (EMT) which is strongly interconnected with H₂O₂ signaling, increased motility and invasiveness. H₂O₂ relays its signal through the installation of oxidative posttranslational modifications on cysteines. The increased H₂O₂ levels that are associated with an EMT confer a heightened sensitivity towards the induction of ferroptosis as a recently discovered vulnerability.

Amivantamab for the treatment of EGFR exon 20 insertion mutant non-small cell lung cancer

INTRODUCTION

Amivantamab is a monoclonal bispecific anti-EGFR-MET antibody that is the first targeted therapy to be approved for non-small cell lung cancer (NSCLC) patients harboring EGFR exon 20 insertion mutations following progression on chemotherapy, marking a watershed moment for a class of mutations which is generally associated with poor outcomes.

AREAS COVERED

In this article, we outline the drug profile of amivantamab compared with EGFR kinase inhibitors under evaluation in EGFR exon 20 insertion mutant NSCLC. We also review the efficacy and safety data reported from the CHRYSALIS phase I trial, which forms the basis of the recent approval of amivantamab.

EXPERT OPINION

Unlike small molecule EGFR kinase inhibitors, amivantamab has an extracellular mode of action and dual activity against EGFR and MET. It remains to be determined what role MET inhibition plays in toxicity and efficacy and whether dual target inhibition can delay the onset of drug resistance in these cancers. Due to its large molecular size, amivantamab is expected to have poor activity to treat brain metastases. Building on the clinical data so far, future trials that will evaluate combination treatments with brain-penetrant EGFR kinase inhibitors will be critical to move the drug toward a first-line treatment.

EGFR-D770>GY and Other Rare EGFR Exon 20 Insertion Mutations with a G770 Equivalence Are Sensitive to Dacomitinib or Afatinib and Responsive to EGFR Exon 20 Insertion Mutant-Active Inhibitors in Preclinical Models and Clinical Scenarios

Epidermal growth factor receptor (EGFR) exon 20 insertion mutations account for a tenth of all EGFR mutations in lung cancers. An important unmet clinical need is the identification of EGFR exon 20 insertion mutants that can respond to multiple classes of approved EGFR-TKIs. We sought to characterize variants involving EGFR-D770 to EGFR-G770 position equivalence changes that structurally allow for response to irreversible 2nd generation EGFR-TKIs. Our group used preclinical models of EGFR exon 20 insertion mutations to probe representative 1st (erlotinib), 2nd (afatinib, dacomitinib), 3rd generation (osimertinib) and EGFR exon 20 insertion mutant-active (poziotinib, mobocertinib) TKIs; we also queried the available clinical literature plus our institutional database to enumerate clinical outcomes. EGFR-D770>GY and other EGFR insertions with a G770 equivalence were identified at a frequency of 3.96% in separate cohorts of EGFR exon 20 insertion mutated lung cancer (n = 429). Cells driven by EGFR-D770>GY were insensitive to erlotinib and osimertinib, displayed sensitivity to poziotinib and dacomitinib and were uniquely sensitive to afatinib and dacomitinib in comparison with other more typical EGFR exon 20 insertion mutations using proliferation and biochemical assays. Clinical cases with EGFR-G770 equivalence from the literature and our center mirrored the preclinical data, with radiographic responses and clinical benefits restricted to afatinib, dacomitinib, poziotinib and mobocertinib, but not to erlotinib or osimertinib. Although they are rare, at <4% of all exon 20 insertion mutations, EGFR-G770 equivalence exon 20 insertion mutations are sensitive to approved 2nd generation EGFR TKIs and EGFR exon 20 insertion mutant-active TKIs (mobocertinib and poziotinib). EGFR-D770>GY and other insertions with a G770 equivalence join EGFR-A763_Y764insFQEA as exon 20 insertion mutationsresponsive to approved EGFR TKIs beyond mobocertinib; this data should be considered for clinical care, genomic profiling reports and clinical trial elaboration.

Optimized Dosing: The Next Step in Precision Medicine in Non-Small-Cell Lung Cancer

In oncology, and especially in the treatment of non-small-cell lung cancer (NSCLC), dose optimization is often a neglected part of precision medicine. Many drugs are still being administered in "one dose fits all" regimens or based on parameters that are often only minor determinants for systemic exposure. These dosing approaches often introduce additional pharmacokinetic variability and do not add to treatment outcomes. Fortunately, pharmacological knowledge is increasing, providing valuable information regarding the potential of, for example, therapeutic drug monitoring. This article focuses on the evidence for the most promising and easily implemented optimized dosing approaches for the small-molecule inhibitors, chemotherapeutic agents, and monoclonal antibodies as treatment options currently approved for NSCLC. Despite limitations such as investigations having been conducted in oncological diseases other than NSCLC or the retrospective origin of many analyses, an alternative dosing regimen could be beneficial for treatment outcomes, prescriber convenience, or financial burden on healthcare systems. This review of the literature provides recommendations on the implementation of dose optimization and advice regarding promising strategies that deserve further research in NSCLC.

Experience of Uncommon EGFR Mutation in Lung Scheme Quality Program: Discussing Risks and Opportunities for the Improvement of Laboratory Response

Background  The quality programs can be considered to be a valuable tool for global and individual growth. Each result, obtained by a single laboratory, contributes to define the standardization of the response. In the case of the uncommon epidermal growth factor receptor (EGFR) mutations, the molecular result is sometimes difficult to interpret in terms of biological significance and therapy choosing. The standardization effort in the diagnostic lung setting also consists of active quality program participation.

Materials and Methods  The quality control analysis, which is defined as a clinical case, was performed by the extraction of DNA from FFPE sections and by RT-PCR on the EGFR (exons 19, 20, 21), BRAF, and KRAS genes. The laboratory performed a validation sequencing of EGFR exon 20 with the help of the Sanger method.

Results  The laboratory reported positivity for EGFR exon 20 insertions and negative results for BRAF and KRAS. The quality test finished with the redaction of a report containing the recommendation to consider the efficacy of therapy with tyrosine kinase inhibitors (TKI). This specific interpretation has determined poor performance judgment by the quality provider, which explained why most of these mutations are TKI-resistant.

Conclusions  This experience provides an opportunity to reflect on the critical aspects of this diagnostic setting. The detection of some uncommon EGFR mutations should entail the mutation characterization, especially for the rare exon 20 insertions, of which are not classifiable as “resistant.” Moreover, this experience allows reflecting on the quality program design, mandatory actions for the laboratory, and routine activity in the oncologic multidisciplinary team.

A phase I/II study of osimertinib in EGFR exon 20 insertion mutation-positive non-small cell lung cancer

OBJECTIVES

Several preclinical data proposed a potential efficacy of osimertinib, a third-generation EGFR tyrosine kinase inhibitor, for EGFR exon 20 insertion (EGFR ex20ins)-positive non-small cell lung cancer (NSCLC). However, reported case series and a retrospective study proposed controversial efficacy. The efficacy of osimertinib in EGFR ex20ins-positive NSCLC have not been well evaluated in prospective clinical trials. In this study, we performed a prospective, single-arm, multi-center, open-label, non-randomized phase I/II study to evaluate efficacy of osimertinib for EGFR ex20ins-positive NSCLC.

MATERIALS AND METHODS

From August 2018 to January 2020, 14 NSCLC patients with EGFR ex20ins were enrolled, of whom 2 were excluded because they did not meet the inclusion criteria. Efficacy and safety of 80 mg osimertinib were evaluated. In addition, we performed a translational exploratory study to clarify the association of mutation type-specific drug sensitivity, osimertinib pharmacokinetic data, and clinical efficacy.

RESULTS

Of the evaluated patients, none experienced objective response, 7 experienced stable disease (58.3%), and 5 experienced disease progression (41.7%). The median progression free survival (PFS) was 3.8 months, and the median overall survival was 15.8 months. Interestingly, the exploratory study demonstrated statistically significant positive correlation between plasma osimertinib concentration/in vitro IC₅₀ ratio and PFS (R = 0.9912, P = 0.0001), highlighting the mutation type-specific concentration-dependent efficacy of osimertinib for EGFR ex20ins-positive NSCLC.

CONCLUSIONS

Regular dose, 80 mg/day, of osimertinib has limited clinical activity in NSCLC patients with EGFR ex20ins. The translational study proposed the potential efficacy of higher dose osimertinib in a subgroup of EGFR ex20ins-positive NSCLC.

Case Report: Osimertinib Followed by Osimertinib Plus Bevacizumab, Personalized Treatment Strategy for a Lung Cancer Patient With a Novel EGFR Exon 20 Insertion D770_N771insGT and Multiple Brain Metastases

Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (EGFR-TKIs) are the standard of care for non–small cell lung cancer (NSCLC) patients with EGFR exon 19 deletion and L858R mutations. However, no EGFR TKI has been approved for NSCLC patients harboring insertion mutations in EGFR exon 20 (EGFRex20ins), a subgroup of uncommon EGFR mutations resistant to first-generation EGFR TKIs. This unmet clinical challenge is further complicated by disease progression due to brain metastases (BMs), which limits the use of EGFR TKIs with low intracranial activity. Osimertinib, a third-generation EGFR TKI with high CNS activity, has demonstrated superior efficacy as a first-line treatment for EGFR-mutant NSCLC with or without BM. The VEGF pathway is a key mediator of cancer metastasis and resistance to EGFR TKIs. Accumulating evidence has demonstrated that the addition of anti-VEGF agents to EGFR TKIs provides an alternative treatment option for the clinical management of EGFR-mutant NSCLC. We herein report an NSCLC case with a novel EGFRex20ins mutation D770_N771insGT and multiple brain metastases who briefly responded to first-line osimertinib treatment and subsequently achieved prolonged disease control with osimertinib plus bevacizumab as second-line treatment. Our case suggests that osimertinib in combination with bevacizumab may be an effective option for NSCLC patients with specific EGFRex20ins mutations and brain metastases.

Globally Approved EGFR Inhibitors: Insights into Their Syntheses, Target Kinases, Biological Activities, Receptor Interactions, and Metabolism

Targeting the EGFR with small-molecule inhibitors is a confirmed valid strategy in cancer therapy. Since the FDA approval of the first EGFR-TKI, erlotinib, great efforts have been devoted to the discovery of new potent inhibitors. Until now, fourteen EGFR small-molecule inhibitors have been globally approved for the treatment of different types of cancers. Although these drugs showed high efficacy in cancer therapy, EGFR mutations have emerged as a big challenge for these drugs. In this review, we focus on the EGFR small-molecule inhibitors that have been approved for clinical uses in cancer therapy. These drugs are classified based on their chemical structures, target kinases, and pharmacological uses. The synthetic routes of these drugs are also discussed. The crystal structures of these drugs with their target kinases are also summarized and their bonding modes and interactions are visualized. Based on their binding interactions with the EGFR, these drugs are also classified into reversible and irreversible inhibitors. The cytotoxicity of these drugs against different types of cancer cell lines is also summarized. In addition, the proposed metabolic pathways and metabolites of the fourteen drugs are discussed, with a primary focus on the active and reactive metabolites. Taken together, this review highlights the syntheses, target kinases, crystal structures, binding interactions, cytotoxicity, and metabolism of the fourteen globally approved EGFR inhibitors. These data should greatly help in the design of new EGFR inhibitors.

Therapeutic exploration of uncommon EGFR exon 20 insertion mutations in advanced non-small cell lung cancer: breaking through brambles and thorns

BACKGROUND

EGFR exon 20 insertion (EGFR ex20ins) mutations account for about 10-12% of all EGFR-mutated tumors, which are usually associated with primary drug resistance to conventional EGFR-TKI therapy and worse survival outcomes, and are currently a major problem for clinicians in clinical management. In recent years, with the rapid improvement of sequencing technology and careful review of clinical data, investigators have gained a deeper understanding and clearer cognition of the clinicopathological features and molecular mechanisms of these EGFR ex20ins mutations.

PURPOSE

The aim of this study was to systemically review the molecular structure and clinical characteristics of EGFR ex20ins mutations, and focus on summarizing the latest data of emerging therapies (including novel small-molecule EGFR-TKI drugs, specific monoclonal antibodies, novel drugs targeting other mechanisms, and immunotherapy) for those patients.

CONCLUSION

Advances in overcoming these systemic challenges have greatly accelerated the development of new drugs targeting EGFR ex20ins, and are committed to designing more rational combination therapies to overcome or delay the emergence of drug resistance, ultimately improve the prognosis of such uncommon mutant populations.

Icotinib, Almonertinib, and Olmutinib: A 2D Similarity/Docking-Based Study to Predict the Potential Binding Modes and Interactions into EGFR

In the current study, a 2D similarity/docking-based study was used to predict the potential binding modes of icotinib, almonertinib, and olmutinib into EGFR. The similarity search of icotinib, almonertinib, and olmutinib against a database of 154 EGFR ligands revealed the highest similarity scores with erlotinib (0.9333), osimertinib (0.9487), and WZ4003 (0.8421), respectively. In addition, the results of the docking study of the three drugs into EGFR revealed high binding free energies (ΔG_b = −6.32 to −8.42 kcal/mol) compared to the co-crystallized ligands (ΔG_b = −7.03 to −8.07 kcal/mol). Analysis of the top-scoring poses of the three drugs was done to identify their potential binding modes. The distances between Cys797 in EGFR and the Michael acceptor sites in almonertinib and olmutinib were determined. In conclusion, the results could provide insights into the potential binding characteristics of the three drugs into EGFR which could help in the design of new more potent analogs.

AZD3759 inhibits glioma through the blockade of the epidermal growth factor receptor and Janus kinase pathways

Glioma is an intracranial malignant tumor with high morbidity in China. Limited efficacy has been achieved in the treatment of glioma through the application of epidermal growth factor receptor (EGFR) inhibitors, which is reported to be related to the poor permeability of the brain–blood barrier (BBB) to EGFR inhibitors. AZD3759 and osimertinib are both BBB-penetrating EGFR inhibitors. The present study aimed to investigate the inhibitory effects of AZD3759 and osimertinib on glioma and compare their efficacy and the underlying mechanisms. C6 and U87 cells were incubated with different concentrations of AZD3759 (1, 2, and 4 μM) and 4 μM osimertinib, respectively. C6-LUC xenograft animals were administered different doses of AZD3759 (15, 30, and 60 mg/kg) and 60 mg/kg osimertinib. We found that proliferation was significantly suppressed and that apoptosis and cell cycle arrest were dramatically induced in both C6 and U87 cells by AZD3759 in a dose-dependent manner. Compared to AZD3759, osimertinib had inferior effects on proliferation, apoptosis, and cell cycle. In vivo experiments verified that the anti-tumor efficacy of AZD3759 against C6 xenograft tumors was dose dependent and superior to that of osimertinib. The inhibitory effects of AZD3759 on the Janus kinase (JAK)/STAT pathway were observed in both glioma cells and tumor tissues, which were more significant than those of osimertinib. In conclusion, AZD3759 may inhibit the progression of glioma via a synergistic blockade of the EGFR and JAK/STAT signaling pathways.

EGFR Exon 20 Insertion in Metastatic Non-Small-Cell Lung Cancer: Survival and Clinical Efficacy of EGFR Tyrosine-Kinase Inhibitor and Chemotherapy

EGFR exon 20 insertions are rare genetic alterations in non-small-cell lung cancers (NSCLCs) that are usually unresponsive to approved EGFR tyrosine kinase inhibitors (TKIs). In this paper, we describe the clinical characteristics, efficacy of EFGR TKIs and chemotherapy, and resulting survival in this population. We retrospectively collected patients with EGFR exon 20 insertions (Exon20ins) from 11 French genetic platforms and paired them (1:2 ratio) with classic Exon 19/21 EGFR mutation patients (controls). Between 2012 and 2017, 35 Exon20ins patients were included. These patients were younger at diagnosis than the controls. All Exon20ins patients who were treated with first-line EGFR TKIs (n = 6) showed progressive disease as the best tumor response. There was no significant difference in the tumor response or the disease control rate with first-line platinum-based chemotherapy between the two groups. A trend towards shorter overall survival was observed in Exon20ins vs. controls (17 months (14-not reach(NR) 95% confidence interval(CI) vs. 29 months (17-NR 95%CI), p = 0.09), respectively. A significant heterogeneity in amino acid insertion in EGFR exon 20 was observed. EGFR exon 20 insertions are heterogeneous molecular alterations in NSCLC that are resistant to classic EGFR TKIs, which contraindicates their use as a first-line treatment.

Molecular Mechanism of EGFR-TKI Resistance in EGFR-Mutated Non-Small Cell Lung Cancer: Application to Biological Diagnostic and Monitoring

Non-small cell lung cancer (NSCLC) is the most common cancer in the world. Activating epidermal growth factor receptor (EGFR) gene mutations are a positive predictive factor for EGFR tyrosine kinase inhibitors (TKIs). For common EGFR mutations (Del19, L858R), the standard first-line treatment is actually third-generation TKI, osimertinib. In the case of first-line treatment by first (erlotinib, gefitinib)- or second-generation (afatinib) TKIs, osimertinib is approved in second-line treatment for patients with T790M EGFR mutation. Despite the excellent disease control results with EGFR TKIs, acquired resistance inevitably occurs and remains a biological challenge. This leads to the discovery of novel biomarkers and possible drug targets, which vary among the generation/line of EGFR TKIs. Besides EGFR second/third mutations, alternative mechanisms could be involved, such as gene amplification or gene fusion, which could be detected by different molecular techniques on different types of biological samples. Histological transformation is another mechanism of resistance with some biological predictive factors that needs tumor biopsy. The place of liquid biopsy also depends on the generation/line of EGFR TKIs and should be a good candidate for molecular monitoring. This article is based on the literature and proposes actual and future directions in clinical and translational research.

Complete Response to Afatinib of an EGFR Exon 18 delE709_T710insD-Mutated Stage IV Lung Adenocarcinoma

Introduction

Epidermal growth factor receptor (EGFR) mutations are frequently found in patients with lung adenocarcinomas, 90% being deletions in exon 19 or point mutation in exon 21. Three generations of tyrosine kinase inhibitors (TKIs) targeting EGFR mutations are available and have changed patient prognosis but less data is available on exon 18 mutations and their sensitivity to TKI therapy. Exon 18 delE709_T710insD accounts for 0.06% (16/27,294) of all EGFR mutations and is an oncogenic driver. Several partial responses to afatinib have been described.

Case description

We report the first case, to the best of our knowledge, of the complete response to afatinib of a 57-year-old patient with stage IV lung adenocarcinoma with a delE709_T710insD mutation in the EGFR gene detected by next-generation sequencing. Oral afatinib was prescribed and despite treatment interruptions and dosage tapering due to cutaneous adverse events, a complete response was achieved 12 months after treatment initiation and is currently maintained at 17 months.

Conclusion

When EGFR mutation is suspected, complete DNA sequencing of exons 18 to 21 should be carried out and we suggest that afatinib should be the first-line treatment for exon 18 delE709_T710insD-mutated advanced lung adenocarcinomas.

LEARNING POINTS

Rare EGFR gene mutations are not detected by standard diagnostic kits.DNA sequencing is required to diagnose rare mutations of the EGFR gene.delE709_T710insD-mutated stage IV lung adenocarcinomas respond to afatinib.

Targeting EGFR Exon 20 Insertions in Non-Small Cell Lung Cancer: Recent Advances and Clinical Updates

Approximately 10% of EGFR-activating mutations occur as in-frame insertion mutations in exon 20 of the EGFR kinase domain (EGFR ins20). EGFR ins20 mutations have not demonstrated the same sensitivity to early generations of EGFR tyrosine kinase inhibitors (TKI) as canonical activating EGFR mutations such as del19 and L858R. Development of effective therapies for this subset of patients has been challenging, but recent years have seen more rapid progress in these efforts. In this review, we describe the molecular and clinicopathologic features of EGFR ins20 mutations and summarize recent data on emerging therapies for patients with this subtype of EGFR-mutant non-small cell lung cancer (NSCLC). SIGNIFICANCE: When activating mutations in EGFR were first discovered in lung cancer, the lack of sensitivity of tumors harboring EGFR ins20 mutations to early-generation EGFR TKIs resulted in this subset of EGFR-mutant tumors being initially classified as an untargetable or intrinsically resistant subpopulation. In addition, the diversity of mutations within EGFR exon 20 and resultant challenges identifying them on routine clinical genotyping tests led to underestimation of their frequency. However, recent scientific progress in targeting EGFR ins20 mutations as well as more effective identification of this clinical cohort has enhanced our ability to develop effective therapies for patients with this subtype of EGFR-mutant NSCLC.

Osimertinib in EGFR-Mutated Lung Cancer: A Review of the Existing and Emerging Clinical Data

The use of epidermal growth factor receptor (EGFR) inhibitors such as osimertinib has improved outcomes and quality of life for patients with EGFR-mutated non-small cell lung cancer (NSCLC). Osimertinib has become the preferred EGFR tyrosine kinase inhibitor (TKIs) for patients with these mutations after demonstrating superior efficacy compared to first generation EGFR TKIs, such as erlotinib and gefitinib. More recently osimertinib has also shown to be beneficial in patients with resectable NSCLC harboring EGFR mutations irrespective of whether they received adjuvant chemotherapy or not. The drug is now FDA approved in this setting. With osimertinib being used more commonly in earlier stage and front-line settings, we are more likely to see patients who develop resistance to this drug. The aim of this review is to provide a comprehensive review of the data with osimertinib in EGFR mutation positive NSCLC, potential resistance mechanisms and an overview of key ongoing clinical trials.

Functional diagnostics using fresh uncultured lung tumor cells to guide personalized treatments

Functional profiling of a cancer patient's tumor cells holds potential to tailor personalized cancer treatment. Here, we report the utility of fresh uncultured tumor-derived EpCAM+ epithelial cells (FUTCs) for ex vivo drug-response interrogation. Analysis of murine Kras mutant FUTCs demonstrates pharmacological and adaptive signaling profiles comparable to subtype-matched cultured cells. By applying FUTC profiling on non-small-cell lung cancer patient samples, we report robust drug-response data in 19 of 20 cases, with cells exhibiting targeted drug sensitivities corresponding to their oncogenic drivers. In one of these cases, an EGFR mutant lung adenocarcinoma patient refractory to osimertinib, FUTC profiling is used to guide compassionate treatment. FUTC profiling identifies selective sensitivity to disulfiram and the combination of carboplatin plus etoposide, and the patient receives substantial clinical benefit from treatment with these agents. We conclude that FUTC profiling provides a robust, rapid, and actionable assessment of personalized cancer treatment options.

Potentiating Therapeutic Effects of Epidermal Growth Factor Receptor Inhibition in Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is a subset of breast cancer with aggressive characteristics and few therapeutic options. The lack of an appropriate therapeutic target is a challenging issue in treating TNBC. Although a high level expression of epidermal growth factor receptor (EGFR) has been associated with a poor prognosis among patients with TNBC, targeted anti-EGFR therapies have demonstrated limited efficacy for TNBC treatment in both clinical and preclinical settings. However, with the advantage of a number of clinically approved EGFR inhibitors (EGFRis), combination strategies have been explored as a promising approach to overcome the intrinsic resistance of TNBC to EGFRis. In this review, we analyzed the literature on the combination of EGFRis with other molecularly targeted therapeutics or conventional chemotherapeutics to understand the current knowledge and to provide potential therapeutic options for TNBC treatment.

Targeting USP13-mediated drug tolerance increases the efficacy of EGFR inhibition of mutant EGFR in non-small cell lung cancer

In non-small cell lung cancer (NSCLC), activating mutations in the epidermal growth factor receptor (EGFR) induce sensitivity to EGFR tyrosine kinase inhibitors. Despite impressive clinical responses, patients ultimately relapse as a reservoir of drug-tolerant cells persist, which ultimately leads to acquired resistance mechanisms. We performed an unbiased high-throughput siRNA screen to identify proteins that abrogate the response of EGFR-mutant NSCLC to EGFR-targeted therapy. The deubiquitinase USP13 was a top hit resulting from this screen. Targeting USP13 increases the sensitivity to EGFR inhibition with small molecules in vitro and in vivo. USP13 selectively stabilizes mutant EGFR in a peptidase-independent manner by counteracting the action of members of the Cbl family of E3 ubiquitin ligases. We conclude that USP13 is a strong mutant EGFR-specific cotarget that could improve the treatment efficacy of EGFR-targeted therapies.

Tpl2 kinase regulates inflammation but not tumorigenesis in mice

Tumor progression locus 2 (Tpl2, gene name MAP3K8), a mitogen-activated protein kinase, is widely expressed in immune and non-immune cells to integrate tumor necrosis factor (TNF), toll-like receptors (TLRs), and interleukin-1 (IL1) receptor signaling to regulate inflammatory response. Given its central role in inflammatory response, Tpl2 is an attractive small molecule drug target. However, the role of Tpl2 as an oncogene or tumor suppressor gene remains controversial, and its function outside immune cells is not understood. We therefore utilized a Tpl2 kinase dead (Tpl2-KD) mouse model in an 18-month aging study to further elucidate Tpl2 effects on lifespan and chronic disease. Histopathological studies revealed the incidence and severity of spontaneous tumors and non-neoplastic lesions were comparable between wild type and Tpl2-KD mice. The only finding was that male Tpl2-KD mice had higher bodyweight and an increased incidence of liver steatosis, suggesting a sex-specific role for Tpl2 in hepatic lipid metabolism. In conclusion, loss of Tpl2 kinase activity did not lead to increased tumorigenesis over aging in mice but affected likely alterations in lipid metabolism in male animals.

Identification of Vinyl Sulfone Derivatives as EGFR Tyrosine Kinase Inhibitor: In Vitro and In Silico Studies

Epidermal growth factor receptor (EGFR), overexpressed in many types of cancer, has been proved as a high potential target for targeted cancer therapy due to its role in regulating proliferation and survival of cancer cells. In the present study, a series of designed vinyl sulfone derivatives was screened against EGFR tyrosine kinase (EGFR-TK) using in silico and in vitro studies. The molecular docking results suggested that, among 78 vinyl sulfones, there were eight compounds that could interact well with the EGFR-TK at the ATP-binding site. Afterwards, these screened compounds were tested for the inhibitory activity towards EGFR-TK using ADP-Glo™ kinase assay, and we found that only VF16 compound exhibited promising inhibitory activity against EGFR-TK with the IC₅₀ value of 7.85 ± 0.88 nM. In addition, VF16 showed a high cytotoxicity with IC₅₀ values of 33.52 ± 2.57, 54.63 ± 0.09, and 30.38 ± 1.37 µM against the A431, A549, and H1975 cancer cell lines, respectively. From 500-ns MD simulation, the structural stability of VF16 in complex with EGFR-TK was quite stable, suggesting that this compound could be a novel small molecule inhibitor targeting EGFR-TK.

Presentation of EGFR mutations in 162 family probands with multiple primary lung cancer

Background

The number of multiple primary lung cancer (MPLC) patients has rapidly increased in recent years. However, information regarding the etiology of MPLC and responsiveness to epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKIs) is rare. The present study aims to describe the mutation signatures of EGFR in MPLC.

Methods

Polymerase chain reaction (PCR) and Sanger sequencing were used to screen EGFR mutations in 162 family probands comprising 366 tumor lesions and 162 paired noncancerous adjacent tissues (NATs). Sequencing data from 3,243 sporadic lung adenocarcinoma (LUAD) samples were analyzed as a control.

Results

Candidate germline mutations were observed in exons 19 (3, 1.85%), 20 (8, 4.94%) and 21 (5, 3.10%), with a total frequency of 9.88% in NATs (16/162). There were 63 probands harboring somatic mutations (63/162, 38.89%), 9 patients harbored the consistency mutations among lesions, and 8 patients carried 2 or more mutations. The overall rate of EGFR somatic mutations was lower in the MPLC probands, but those of exon 19 p.747-752del, 20 p.V769indelsVASV and 20 p.D770indelsDSVD were significantly higher in MPLC probands than in patients with sporadic LUAD.

Conclusions

There exists unique EGFR mutation signatures in a large cohort of MPLC probands, which might provide objective evidence of the etiology and effectiveness of clinical TKI treatment of high-risk MPLC patients.

Mobocertinib (TAK-788): A Targeted Inhibitor of EGFR Exon 20 Insertion Mutants in Non-Small Cell Lung Cancer

Most EGFR exon 20 insertion (EGFRex20ins) driver mutations in non-small cell lung cancer (NSCLC) are insensitive to approved EGFR tyrosine kinase inhibitors (TKI). To address the limitations of existing therapies targeting EGFR-mutated NSCLC, mobocertinib (TAK-788), a novel irreversible EGFR TKI, was specifically designed to potently inhibit oncogenic variants containing activating EGFRex20ins mutations with selectivity over wild-type EGFR. The in vitro and in vivo activity of mobocertinib was evaluated in engineered and patient-derived models harboring diverse EGFRex20ins mutations. Mobocertinib inhibited viability of various EGFRex20ins-driven cell lines more potently than approved EGFR TKIs and demonstrated in vivo antitumor efficacy in patient-derived xenografts and murine orthotopic models. These findings support the ongoing clinical development of mobocertinib for the treatment of EGFRex20ins-mutated NSCLC. SIGNIFICANCE: No oral EGFR-targeted therapies are approved for EGFR exon 20 insertion (EGFRex20ins) mutation-driven NSCLC. Mobocertinib is a novel small-molecule EGFR inhibitor specifically designed to target EGFRex20ins mutants. Preclinical data reported here support the clinical development of mobocertinib in patients with NSCLC with EGFR exon 20 insertion mutations.See related commentary by Pacheco, p. 1617.This article is highlighted in the In This Issue feature, p. 1601.

Clinicopathologic Significance of EGFR Mutation and HPV Infection in Sinonasal Squamous Cell Carcinoma

Sinonasal squamous cell carcinoma (SNSCC) is sometimes associated with high-risk human papillomavirus (HR-HPV) infection and inverted sinonasal papilloma or oncocytic sinonasal papilloma. Frequent mutations of EGFR and KRAS are reported in inverted sinonasal papilloma-related sinonasal squamous cell carcinoma (ISP-SCC) and oncocytic sinonasal papilloma-related SNSCC, respectively. Here, we attempted to determine the prevalence and the prognostic significances of these alterations in SNSCC. We retrospectively collected 146 SNSCCs, including 14 ISP-SCCs, and comprehensively analyzed the HR-HPV infection by human papillomavirus (HPV)-RNA in situ hybridization, EGFR gene copy number gain (CNG) by chromogenic in situ hybridization, and gene mutations in EGFR and KRAS by Sanger sequencing. HR-HPV was detected in 11 cases (7.5%), whereas all 14 ISP-SCCs were negative. EGFR mutations were present in 21 (14.7%) of 143 SNSCCs, including 13/14 (92.9%) ISP-SCCs and 8/129 (6.2%) non-ISP-SCCs (P<0.0001). The majority of EGFR mutations were exon 20 insertions, with the remainder composed of deletions and single-nucleotide substitutions in exons 19 and 20. All of 142 SNSCCs harbored no KRAS mutation. EGFR CNG was detected in 41 (28.1%) of 146 SNSCCs; all of them were HPV negative and 3 had EGFR mutations. Collectively, EGFR mutation, EGFR CNG, and HR-HPV were essentially mutually exclusive, and each subgroup had distinct clinicopathologic features. The HPV-negative/EGFR-mutant group, the HPV-negative/EGFR CNG-positive group, and the triple-negative group had significantly worse prognoses than the HPV-positive group (P=0.0265, 0.0264, and 0.0394, respectively). In conclusion, EGFR mutation may play a pathogenetically important role in some populations of SNSCCs, especially ISP-SCCs. The molecular subclassification of SNSCCs may contribute to prognostic prediction and molecular-targeted precision medicine.