Common Epidermal Growth Factor Receptor Research Articles

From Rarity to Reality: Osimertinib's Promising Horizon in Treating Uncommon EGFR Mutations in Non-Small Cell Lung Cancer.

In the realm of advanced non-small cell lung cancer (NSCLC) harboring epidermal growth factor receptor (EGFR) therapy with tyrosine kinase inhibitors (TKIs), addressing optimal treatment for uncommon EGFR mutations like G719X in exon 18, S768I in exon 20, and L861Q in exon 21 remains a pivotal yet challenging frontier. Contrary to the well-established efficacy of EGFR-TKIs in common EGFR mutations, these uncommon alterations pose unmet medical needs due to a lack of comprehensive evidence. While afatinib, a second-generation EGFR-TKI, has received FDA approval for patients with these uncommon EGFR mutations, the approval was based on a post-hoc analysis of randomized clinical trials. Recent developments include multiple clinical trials investigating the efficacy of both second and third-generation EGFR-TKIs in patients with uncommon EGFR mutations. A noteworthy example is a prospective phase II trial of osimertinib including the landmark UNICORN study, which has shown promising results in treating uncommon EGFR mutations. Despite various reports on the efficacy of afatinib and osimertinib in treating uncommon EGFR mutations, the appropriate use of these TKIs remains unclear. This review aims to consolidate the findings from the latest clinical trials focused on uncommon EGFR mutations, outlining variations in the therapeutic efficacy of these TKIs based on the specific genetic mutation. By synthesizing these findings, we aim to guide oncologists towards more informed decisions in employing TKIs for NSCLC with uncommon EGFR mutations other than exon 20 insertion. Additionally, we explore potential treatment strategies tailored to these patient populations to address the challenges posed by these mutations.

Distinguishing EGFR mutation molecular subtypes based on MRI radiomics features of lung adenocarcinoma brain metastases

ObjectiveTo explore the feasibility of identifying epidermal growth factor receptor (EGFR) mutation molecular subtypes in primary lesions based on the radiomics features of lung adenocarcinoma brain metastases using magnetic resonance imaging (MRI). MethodsWe retrospectively analyzed clinical, imaging, and genetic testing data of patients with lung adenocarcinoma with EGFR gene mutations who had brain metastases. Three-dimensional radiomics features were extracted from contrast-enhanced T1-weighted images. The volume of interest was delineated and normalized using Z-score, dimensionality reduction was performed using principal component analysis, feature selection using Relief, and radiomics model construction using adaptive boosting as a classifier. Data were randomly divided into training and testing datasets at an 8:2 ratio. Five-fold cross-validation was conducted in the training set to select the optimal radiomics features and establish a predictive model for distinguishing between exon 19 deletion (19Del) and exon 21 L858R point mutation (21L858R), the two most common EGFR gene mutations. The testing set was used for external validation of the models. Model performance was evaluated using receiver operating characteristic curve and decision curve analyses. ResultsOverall, 86 patients with 228 brain metastases were included. Patient age was identified as an independent predictor for distinguishing between 19Del and 21L858R. The area under the curve (AUC) values of the radiomics model in the training and testing datasets were 0.895 (95% confidence interval [CI]: 0.850−0.939) and 0.759 (95% CI: 0.0.614−0.903), respectively. The AUC for diagnosis of all cases using a combined model of age and radiomics was 0.888 (95% CI: 0.846−0.930), slightly higher than that of the radiomics model alone (0.866, 95% CI: 0.820−0.913), but without statistical significance (p=0.1626). In the decision curve analysis, both models demonstrated clinical net benefits. ConclusionsThe radiomics model based on MRI of lung adenocarcinoma brain metastases could distinguish between EGFR 19Del and 21L858R mutations in the primary lesion.

Abstract 2355: SGN-EGFRd2 binding and activity are agnostic to common EGFR extracellular resistance mutations acquired in response to anti-EGFR targeted antibody therapies

Abstract SGN-EGFRd2 is an investigational bispecific antibody comprised of two camelid-derived humanized variable heavy chain only (VHH) domains, one targeting Vγ9Vδ2 (gamma delta) T cells and the other targeting the epidermal growth factor receptor (EGFR). Selective antitumor activity occurs when two conditions are met: 1) the molecule engages both EGFR-expressing tumor cells and gamma delta T cells and 2) butyrophilins, in complex with phosphoantigens (pAgs), are expressed by EGFR-positive tumor cells, resulting in gamma delta T cell directed tumor cell killing by activation, degranulation and secretion of cytolytic molecules. The tumor specific proximity of gamma delta T cells and expression of the butyrophilins/pAgs complex results in the killing of EGFR-expressing tumor cells but not EGFR-expressing normal cells. EGFR is an oncogenic receptor tyrosine kinase and target of several classes of therapeutic modalities, including antibodies. Two antibodies are currently approved for the treatment of EGFR-expressing, KRAS wild-type metastatic colorectal cancer (mCRC): cetuximab (CET) and panitumumab (PAN). Although these anti-EGFR therapies provide significant survival benefits to patients, the duration of response is transient, and most patients progress and develop secondary resistance [1]. One such escape mechanism is the acquisition of mutations in the extracellular domain (ECD) of EGFR, which prevent binding of therapeutic antibodies [2]. Because SGN-EGFRd2 will be tested on patients previously exposed to anti-EGFR therapeutic antibodies, it is paramount to assess its binding to EGFR ECD mutations identified in antibody resistant mCRC patients. EGFR-negative A2058 cells were transduced to express wild type EGFR and a panel of EGFR ECD resistance mutations (N=16). The binding specificity and kinetics of SGN-EGFRd2 were compared to CET and PAN by flow cytometry on engineered cell lines and biolayer interferometry, respectively. Results indicated SGN-EGFRd2 maintained the ability to bind to all tested EGFR ECD mutants, whereas CET and PAN were unable to bind several ECD mutants, as previously described [3,4]. SGN-EGFRd2 binding to EGFR ECD mutant cell lines induced the production of interferon gamma and expression of cell surface CD107a on gamma delta T cells, confirming functional engagement. In contrast to current anti-EGFR therapeutic antibodies, SGN-EGFRd2 binding and activity was unaffected by commonly identified EGFR ECD mutations. These findings highlight SGN-EGFRd2 as a novel molecule targeting wild-type EGFR and common EGFR ECD mutations identified in the mCRC setting. Citation Format: Liem Nguyen, Chun-Shu Wong, Serena Wo, Bryan Grogan, Daniel Diolaiti, Maria Corinna Palanca-Wessels, Astrid Clarke. SGN-EGFRd2 binding and activity are agnostic to common EGFR extracellular resistance mutations acquired in response to anti-EGFR targeted antibody therapies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2355.

Abstract 5774: Are 19del and L858R really not the same disease entities

Abstract IntroductionThe similarities and differences between the two subtypes of common epidermal growth factor receptor (EGFR) mutations have been recognized by clinicians, but actual treatment strategies remain unchanged. The L858R mutation can be explained by the pharmacological conformational plasticity of the receptor protein and other co-occurring mutations, which may be subtypes of EGFR mutations or non-EGFR mutations, and differences in downstream signaling pathways. As long as we know that molecular differences lead to biological differences, it is a challenge for all of us that our treatment strategies must changeWe investigated the RWD, conformational structure and RNA expression profile about two types of common mutations in the mEGFR+ NSCLC patients.MethodWe collected the medical information for stage I-IIIA mEGFR+ NSCLC patients and explored the conformational structure by crystalized radiologic technique. And we performed RNA expression assay using multiplex IF and High-through-output Profiling. ResultOverall, the static structures of wild type (WT), L858R, and 19del (ΔL747-E749) EGFR did not show any significant differences. However, the difference in the static structure between WT-19del and L858R-19del was subtly greater than that of WT-L858R. In addition, further analyses demonstrated no significant structural differences in the phosphorylation sites. However, it should be noted that proteins do not exist as static structures in vivo, and they have a dynamic, flexible structure that changes over time, i.e., plasticity of proteins. Therefore, we investigated the X-ray B-factor value, which is an indicator of flexibility, dynamics, and plasticity of proteins. As expected, the loop or disordered regions mainly shows higher B-factor values, which indicates an active structure, highly changeable and dynamic. Together, the three types of the EGFR protein manifest wholly similar B-factor values, while several local regions present appreciably distinct B-factors. Physical properties such as the dynamic structure may affect intermolecular recognition of EGFR proteins and their function Recent biochemical and biophysical evidence suggests that oncogenic mutations have an impact on the conformational dynamics of enzymesConclusionIn conclusion, our results suggest that Patients with 19del and L858R mutations demonstrated a different clinical course. It is necessary to consider the dynamic structural characteristics and functional differences of EGFR membrane proteins. Citation Format: Yunseok Heo, Joo Ri Kim, Yeoun Eun Sung, Seoree Kim, Chan Kwon Jung, Jeong-Oh Kim, Jeong-yeon Shin, Guk Jin Lee, Sang hoon Chun, Seong Hyeon Bu, Young Ho Lee, Jin Hyoung Kang. Are 19del and L858R really not the same disease entities [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5774.

Abstract 5868: Upregulation of HER3 and MET in non-small cell lung cancer cells resistant to EGFR tyrosine kinase inhibitor

Abstract Introduction: Prior research demonstrates the importance of studying epidermal growth factor receptor (EGFR) activating mutations for better understanding the biology of non-small cell lung cancer (NSCLC), which comprises the majority (~80%) of lung cancers. EGFR-targeted tyrosine kinase inhibitors (TKIs) have been used in the clinic to treat NSCLC with EGFR activating mutations. First and second-generation EGFR-TKIs are effective in NSCLC patients with the most common EGFR mutations (exon 19 deletion (Del19) and exon 21-point mutation (L858R)). A third generation EGFR-TKI, osimertinib (AZD9291), has been developed to target the T790M resistance mutation, but patients are starting to show resistance to this line of therapy as well. Our study aims to elucidate the underlying mechanism(s) of EGFR-TKI resistance in NSCLC cells. Methods: NSCLC cell lines, including PC-9 and HCC827, which have the Del19 EGFR activating mutation, were utilized for experiments. From the parental cell lines, several cell lines resistant to the EGFR-TKIs were previously established. Cell proliferation (MTS) assays were used to confirm the resistance phenotype of the established cell lines. Western blot assays and RT-qPCR were utilized to determine changes in the expression level of several membrane receptors and their downstream effectors. Results: Our preliminary analysis showed that both human epidermal growth factor 3 (HER3) and mesenchymal-epithelial transition factor (MET) were upregulated in the EGFR-TKI-resistant cell lines as compared to their parental counterparts. Further studies revealed an increased level of phosphorylated STAT3 (p-STAT3) and ERK1/2 (p-ERK1/2) in the resistant cell lines when compared to the parental cell lines, suggesting the possible involvement of HER3 and/or MET in the activation of downstream signaling pathways. Upregulation of HER3 and MET was found at both the protein and mRNA level. Conclusion: Based on our initial findings, membrane receptors, including HER3 and MET, could be working together to continue activating downstream signaling pathways to evade the effects of osimertinib, resulting in resistance. Additional work is underway to define the role of HER3 and MET in the NSCLC cells resistant to EGFR-TKIs. Citation Format: Margaret Larsen, Hui Lyu, CongCong Tan, Yakun Wu, Bolin Liu. Upregulation of HER3 and MET in non-small cell lung cancer cells resistant to EGFR tyrosine kinase inhibitor [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5868.

Impact of central nervous system metastasis after complete resection of lung adenocarcinomas harboring common EGFR mutation – A real-world database study in Japan: The CReGYT-01 EGFR study

ObjectivesTo clarify the impact of central nervous system (CNS) metastasis on performance status (PS) at relapse, on subsequent treatment(s), and on survival of patients with lung adenocarcinoma harboring common epidermal growth factor receptor (EGFR) mutation. MethodsWe conducted the multicenter real-world database study for patients with radical resections for lung adenocarcinomas between 2015 and 2018 at 21 centers in Japan. EGFR mutational status was examined at each center. ResultsOf 4181 patients enrolled, 1431 underwent complete anatomical resection for lung adenocarcinoma harboring common EGFR mutations. Three-hundred-and-twenty patients experienced disease relapse, and 78 (24%) had CNS metastasis. CNS metastasis was significantly more frequent in patients with conventional adjuvant chemotherapy than those without (30% vs. 20%, P = 0.036). Adjuvant chemotherapy did not significantly improve relapse-free survival at any pathological stage (adjusted hazard ratio for stage IA2–3, IB, and II-III was 1.363, 1.287, and 1.004, respectively). CNS metastasis did not affect PS at relapse. Subsequent treatment, mainly consisting of EGFR-tyrosine kinase inhibitors (TKIs), could be equally given in patients with or without CNS metastasis (96% vs. 94%). Overall survival after relapse was equivalent between patients with and without CNS metastasis. ConclusionThe efficacy of conventional adjuvant chemotherapy may be limited in patients with lung adenocarcinoma harboring EGFR mutations. CNS metastasis is likely to be found in practice before deterioration in PS, and may have little negative impact on compliance with subsequent EGFR-TKIs and survival after relapse. In this era of adjuvant TKI therapy, further prospective observational studies are desirable to elucidate the optimal management of CNS metastasis.

Rare oncogenic alterations in NSCLC—focus on atypical EGFR mutations

SummaryIn non-small cell lung cancer (NSCLC), mutations within the epidermal growth factor receptor (EGFR) gene are very common driver mutations. EGFR tyrosine kinase inhibitors (TKIs), have shown remarkable efficacy in patients with common classical EGFR mutations (L858R and exon 19 deletions). However, the landscape becomes intricate with atypical (also known as uncommon) EGFR mutations, comprising up to 30% of cases. This brief review provides an insight into recent studies, shedding light on the challenges and opportunities posed by uncommon mutations. The exploration encompasses clinical outcomes, treatment responses, and innovative approaches such as structure-based classifications, offering insights into the evolving paradigm of precision medicine for NSCLC patients with diverse EGFR mutations.

A real-world cohort study of first-line afatinib in patients with EGFR-mutant advanced non-small cell lung cancer in Vietnam

BackgroundThis study aimed to evaluate the efficacy and side effects of first-line afatinib treatment in a real-world setting in Vietnam.MethodsThis retrospective study was conducted across nine hospitals in Vietnam. Advanced epidermal growth factor receptor (EGFR)-mutant non-small cell lung cancer (NSCLC) patients who received afatinib as first-line therapy between April 2018 and June 2022 were included, and patient medical records were reviewed. Key outcomes were overall response rate (ORR), time-to-treatment failure (TTF), and tolerability.ResultsA total of 343 patients on first-line afatinib were eligible for the study. EGFR exon 19 deletion (Del19) alone was detected in 46.9% of patients, L858R mutation alone in 26.3%, and other uncommon EGFR mutations, including compound mutations, in 26.8%. Patients with brain metastases at baseline were 25.4%. Patients who received 40 mg, 30 mg, and 20 mg as starting doses of afatinib were 58.6%, 39.9%, and 1.5%, respectively. The ORR was 78.1% in the overall population, 82.6% in the Del19 mutation subgroup, 73.3% in the L858R mutation subgroup, and 75.0% in the uncommon mutation subgroup (p > 0.05). The univariate and multivariate analyses indicate that the ORR increased when the starting dose was 40 mg compared to starting doses below 40 mg (83.9% vs. 74.3%, p = 0.034). The median TTF (mTTF) was 16.7 months (CI 95%: 14.8–18.5) in all patients, with a median follow-up time of 26.2 months. The mTTF was longer in patients in the common EGFR mutation subgroup (Del19/L858R) than in those in the uncommon mutation subgroup (17.5 vs. 13.8 months, p = 0.045) and in those without versus with brain metastases at baseline (17.5 vs. 15.1 months, p = 0.049). There were no significant differences in the mTTF between subgroups based on the starting dose of 40 mg and < 40 mg (16.7 vs. 16.9 months, p > 0.05). The most common treatment-related adverse events (any grade/grade ≥ 3) were diarrhea (55.4%/3.5%), rash (51.9%/3.2%), paronychia (35.3%/5.0%), and stomatitis (22.2%/1.2%).ConclusionsAfatinib demonstrated clinical effectiveness and good tolerability in Vietnamese EGFR-mutant NSCLC patients. In our real-world setting, administering a starting dose below 40 mg might result in a reduction in ORR; however, it might not have a significant impact on TTF.

Immunohistochemical analysis of epidermal growth factor receptor as a predictive biomarker in lung adenocarcinoma – A cross-sectional study of 33 cases on computed tomography-guided core needle biopsy specimens

Background: Lung cancer is the second most common cause of cancer in all ages and both genders and is the leading cause of cancer death. Two major groups of lung cancers are – small cell lung carcinoma (SCLC) and non-SCLC (NSCLC). Due to discovery of driver mutation such as epidermal growth factor receptor (EGFR) mutation in NSCLC, the paradigm of lung cancer therapy has shifted from cytotoxic platinum based therapy to tyrosine kinase inhibitor (TKI) therapy. In this study, we have analyzed EGFR expression in NSCLC by immunohistochemistry (IHC) and studied the response to TKI therapy in terms of progression free survival (PFS) and overall survival (OS). Aims and Objectives: In this study, we have retrospectively analyzed the EGFR overexpression in adenocarcinoma of lung in core needle biopsy (CNB) specimen by IHC analysis and correlated with the therapeutic response and survival rate (OS and PFS) in lung carcinoma patients. Materials and Methods: We have analyzed retrospectively EGFR expression in lung adenocarcinoma cases (computed tomography-guided CNB specimen) by IHC. In our study, we have used monoclonal primary antibodies against two most common EGFR mutations, that is, L858R point mutation and E 746–A 750 deletion. Results: Out of 33 cases, EGFR expression was seen in 28 cases. For EGFR expression assessment by IHC, both cytoplasmic and/or membranous staining taken into consideration. EGFR positivity was interpreted only when &gt;10% tumor cells having 2+ or more intensely staining pattern. The response to TKI therapy in terms of PFS and OS was also studied. Conclusion: IHC analysis of EGFR mutation using specific antibodies has extremely high specificity with good sensitivity. Use of targeted therapy in the form of TKI in EGFR positive lung adenocarcinoma has high response rate and long duration of survival (PFS and OS) with acceptable toxicity profile in contrast to the conventional therapy.

Epidermal Growth Factor Receptor Exon 19 Deletion Subtypes Do Not Influence Survival Outcomes Following First-line Epidermal Growth Factor Receptor-tyrosine Kinase Inhibitors in Advanced Nonsmall Cell Lung Cancer Patients

Abstract Background: Several deletion and insertion subtypes occur in exon 19 of the epidermal growth factor receptor (EGFR) gene, collectively called exon 19 deletions (del19), and are one of the common EGFR mutations in nonsmall cell lung cancer (NSCLC). Previous studies have shown that del19 subtypes might influence the response to tyrosine kinase inhibitors (TKIs), but their findings have been inconsistent. Therefore, this study aimed to evaluate the impact of del19 subtypes in an Asian population and provide additional evidence on this issue. Materials and Methods: NSCLC patients treated at Chang Gung Medical Hospitals between 2011 and 2018 were retrospectively reviewed. Their clinicopathological characteristics, clinical tumor response, progression-free survival (PFS), and overall survival (OS) were collected. PFS was evaluated among different del19 subtypes and EGFR-TKIs. Results: This study included 164 patients with NSCLC carrying an EGFR del19 mutation who had detailed information about their del19 subtype and were treated with frontline EGFR-TKIs (39 with afatinib and 125 with gefitinib/erlotinib). In this cohort, del19 subtypes did not influence PFS and OS based on different classifications, including start codon of deletion, the number of deleted nucleotides, or pure deletion versus mixed deletion/insertion/substitution. In addition, afatinib generally showed better PFS than gefitinib/erlotinib, particularly and significantly for patients with the p. E746_A750 mutation, a common 15 nucleotide deletion, or a pure deletion without insertion/substitution. Conclusion: In this study, del19 subtypes did not influence PFS and OS with EGFR-TKIs. Afatinib showed better activity than first-generation TKIs and should be preferred for patients with del19 mutations.

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

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

Patterns of progression on first line osimertinib in patients with EGFR mutation-positive advanced non-small cell lung cancer (NSCLC): A Swiss cohort study

AimOsimertinib is a third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) approved for patients with EGFR mutated non-small cell lung cancer as first-line treatment. However, treatment resistance inevitably emerges and may present as oligo-progressive disease (OPD) or systemic progressive disease (SPD). The incidence of OPD on first-line osimertinib is unknown. MethodsWe retrospectively analyzed patients who received first-line osimertinib at 13 Swiss centers. The rate of OPD (PD in ≤ 5 lesions) and treatment outcomes were analyzed. ResultsThe median age of the 148 patients was 68.2 years (range. 38.0–93.3). There were 62 % females, 83 % with a PS ≤ 1, 59 % never smokers, 57 % of patients with an EGFR exon 19 deletion and 37 % with EGFR p.L858R exon 21. 77 % experienced OPD. Median overall survival (OS) was 51.6 months (95 % CI, 38.4–65.0). Median progression-free survival (PFS) was 19.2 (95 % CI, 14.3–23.5) and 8.7 (95 % CI, 2.8–15.6) months for patients with common and uncommon EGFR mutations. Patients with OPD compared to SPD had a significantly longer time to treatment failure and longer OS of (22.9 vs. 10.8 months, p < 0.001 and 51.6 vs. 26.4 months, p = 0.004, respectively). The most common organ sites of PD were lung (62 %), brain (30 %), lymph nodes (30 %), bone (27 %) and pleura (27 %). Twenty-six patients (45 %) with OPD received local ablative treatment (LAT). The OS of OPD patients with LAT was 60.0 (95 % CI, 51.6-NA) vs. 51.4 (95 % CI 38.4–65.3) months (p = 0.43) without LAT. ConclusionThe rate of OPD of patients receiving first line osimertinib was 77 %. Patients with OPD had a significantly better OS compared to patients with SPD (51.6 vs. 26.4 months). Patients with OPD receiving LAT had the longest median OS (60.0 months).

Long-term follow-up of a consecutive cohort validating an epidermal growth factor receptor mutation as an independent risk factor for postoperative recurrence in lung adenocarcinoma.

Third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors were recently reported to be effective as adjuvant therapy for resected lung adenocarcinoma (ADC) harbouring common EGFR mutations. However, whether the EGFR mutation is a direct risk factor for postoperative recurrence remains unknown. Therefore, we conducted a multi-institutional observational study to compare postoperative survival according to EGFR mutation status. We collected the medical records of consecutive patients who underwent surgical resection for ADC between 2005 and 2012 at 4 participating institutions. Recurrence-free survival (RFS) and overall survival (OS) associated with EGFR mutation status were evaluated. We further analysed survival after pair-matching patients' clinicopathological characteristics. EGFR mutations were harboured by 401 of 840 (48%) enrolled patients. The number of patients with an EGFR mutation (M group) differed from that with the EGFR wild-type sequence (W group) in terms of sex, smoking history and pathological stage. The median follow-up period was 85 months. The five-year RFS/OS rates of the M and W groups were 70%/85% and 61%/75%, respectively (P < 0.001 for both groups). However, multivariable analysis revealed that EGFR mutation status was not independently related with both RFS and OS. In pair-matched analysis, the RFS and OS curves of the patients with an EGFR mutation and wild-type sequence were not statistically different, either. Long-term follow-up of consecutive patients did not show that a common EGFR mutation was an independent risk factor of recurrence or prognostic factor for completely resected lung ADC.

Clinical, Genomic, and Transcriptomic Featurses of Lung Adenocarcinoma With Uncommon EGFR Mutation

PurposeThe purpose of this study is to identify the clinical, genomic, and transcriptomic features of patients with lung adenocarcinoma (LUAD) harboring uncommon epidermal growth factor receptor (EGFR) mutations (UCM) compared with common EGFR mutations (CM). Materials and MethodsIn this multicenter retrospective cohort study, clinicopathological data were collected from 1047 consecutive patients who underwent complete surgical resection for LUAD, as well as EGFR mutation analysis, between 2005 and 2012 at 4 institutions. Differences in postoperative overall survival (OS) and recurrence-free survival (RFS) according to EGFR mutation status were evaluated. For the genomic and transcriptomic analyses, 5 cohorts from public databases were evaluated. ResultsOf 466 eligible patients, 415 (89.1%) and 51 (10.9%) had CM and UCM, respectively. The 5-year OS and RFS rates in the CM/UCM groups were 86.8%/77.0% and 74.8%/59.0%, respectively. OS and RFS were significantly shorter in the UCM than CM group (both P < .01). Multivariable analysis of OS showed that UCM was an independent prognostic factor (hazard ratio 1.72, 95% confidential interval 1.01-2.93). According to the genomic analysis, tumors with UCM had a significantly higher tumor mutation burden and TP53 mutation frequency. Transcriptomic analysis showed that the T-cell-inflamed gene signature, a biomarker of the treatment for immunotherapy, was significantly associated with tumors with UCM. ConclusionUCM were associated with a poor prognosis in patients with surgically resected EGFR-mutated LUAD. Tumors with UCM had unique genomic and transcriptomic features suggestive of a tumor microenvironment responsive to immunotherapy.

Do patient characteristics affect EGFR tyrosine kinase inhibitor treatment outcomes? A network meta-analysis of real-world survival outcomes of East Asian patients with advanced non-small cell lung cancer treated with first-line EGFR-TKIs.

Despite the well-established efficacies of tyrosine kinase inhibitors (TKIs) in epidermal growth factor receptor (EGFR)-mutated non-small cell lung cancer (NSCLC), there is limited real-world evidence comparing their effectiveness according to patients' clinical characteristics. This network meta-analysis (NMA) compared survival outcomes among first-line EGFR-TKIs in different subgroups of East Asian patients with advanced NSCLC. This NMA included real-world observational studies reporting outcomes with TKIs in patients aged >65 years, with baseline brain metastasis, with different Eastern Cooperative Oncology Group (ECOG) statuses, or with different common EGFR mutation types. In patients with the EGFR L858R mutation, afatinib resulted in significantly longer progression-free survival (PFS) than erlotinib (hazard ratio [HR]: 0.59, 95% confidence interval [CI]: 0.46-0.75) and gefitinib (HR: 0.41, 95% CI: 0.32-0.53). Similarly, in patients with the EGFR Del19 mutation, afatinib and erlotinib resulted in significantly longer PFS than gefitinib (HR: 0.48 with 95% CI: 0.33-0.71 and HR: 0.54 with 95% CI: 0.36-0.80, respectively). Moreover, afatinib resulted in significantly longer PFS than gefitinib in patients with brain metastasis (HR: 0.53, 95% CI: 0.33-0.87) or ECOG status 0-1 (HR: 0.37, 95% CI: 0.23-0.59). This NMA suggests that afatinib results in similar PFS to erlotinib and superior PFS than gefitinib in patients with Del19 mutant NSCLC, aged ≥65 years, with ECOG scores of 0-1, and with baseline brain metastasis.

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.

Nuclear epidermal growth factor receptor as a therapeutic target.

Epidermal growth factor receptor (EGFR) is one of the most well-studied oncogenes with roles in proliferation, growth, metastasis, and therapeutic resistance. This intense study has led to the development of a range of targeted therapeutics including small-molecule tyrosine kinase inhibitors (TKIs), monoclonal antibodies, and nanobodies. These drugs are excellent at blocking the activation and kinase function of wild-type EGFR (wtEGFR) and several common EGFR mutants. These drugs have significantly improved outcomes for patients with cancers including head and neck, glioblastoma, colorectal, and non-small cell lung cancer (NSCLC). However, therapeutic resistance is often seen, resulting from acquired mutations or activation of compensatory signaling pathways. Additionally, these therapies are ineffective in tumors where EGFR is found predominantly in the nucleus, as can be found in triple negative breast cancer (TNBC). In TNBC, EGFR is subjected to alternative trafficking which drives the nuclear localization of the receptor. In the nucleus, EGFR interacts with several proteins to activate transcription, DNA repair, migration, and chemoresistance. Nuclear EGFR (nEGFR) correlates with metastatic disease and worse patient prognosis yet targeting its nuclear localization has proved difficult. This review provides an overview of current EGFR-targeted therapies and novel peptide-based therapies that block nEGFR, as well as their clinical applications and potential for use in oncology.

A phase 1 study to assess BDTX-1535, an oral EGFR inhibitor, in patients with glioblastoma or non–small-cell lung cancer.

TPS9156 Background: The epidermal growth factor receptor (EGFR) is a potent oncogene commonly altered in many cancers, including glioblastoma (GBM) and non-small cell lung cancer (NSCLC). EGFR tyrosine kinase activity driven by common EGFR mutations can be inhibited by small molecules, however, resistance to available agents may be driven by mutations in the EGFR active kinase site or other regions. BDTX-1535 is an orally available, highly potent, selective, irreversible inhibitor of EGFR mutations, including extracellular variants and amplifications commonly expressed in GBM and inhibits the common and uncommon EGFR mutations found in NSCLC, including the C797S mutation acquired following 3rd generation EGFR inhibitor therapy. Preclinical data demonstrated the ability of BDTX-1535 to cross the blood-brain barrier and produce sustained inhibition of EGFR signaling. Preclinical studies suggest that BDTX-1535 has the potential to be clinically active in suppressing tumor growth in patients with GBM and NSCLC with or without CNS metastases, including a potential survival benefit. Methods: BDTX-1535-101 (NCT05256290) is Phase 1, open-label, multicenter study to assess the safety, tolerability, PK, CNS activity, and preliminary antitumor activity of BDTX-1535 in recurrent GBM (rGBM) or locally advanced or metastatic NSCLC with or without CNS disease. The Monotherapy Dose Escalation portion will evaluate BDTX-1535 in patients with either rGBM expressing EGFR alterations or locally advanced/metastatic NSCLC harboring sensitizing EGFR mutations with or without CNS disease. Patients with rGBM must have previously received available standard therapy of surgical resection followed by chemoradiotherapy and/or temozolomide (TMZ). Eligible NSCLC patients must have EGFR mutated NSCLC that has progressed following standard of care EGFR inhibitor therapy. Once a provisional recommended Phase 2 dose (RP2D) has been established, BDTX-1535 monotherapy will be explored in the following Dose Expansion cohorts to further evaluate safety, PK, and preliminary assessment of efficacy: 1) rGBM with confirmed EGFR alterations, 2) NSCLC with uncommon EGFR mutations following EGFR inhibitor therapy; 3) NSCLC with acquired EGFR resistance mutation following a 3rd generation EGFR inhibitor in 1L setting. NSCLC patients may enroll with or without CNS metastases and must not be known to express excluded resistance mutations such as EGFR T790M or MET. BDTX-1535 will also be studied in combination with TMZ to assess safety, tolerability, and a recommended combination dose for the treatment of patients with rGBM harboring EGFR mutations or variants. Enrollment was initiated in 2022 and dose escalation is ongoing. Dose Expansion cohorts are expected to open in 2023. For additional information, please contact BDTX_1535_101_Study@bdtx.com . Clinical trial information: NCT05256290 .

L858R-K860I Doublet Mutation of EGFR gene in Non-Small Cell Lung Carcinoma: Cause of a False Negative Call for L858R on Initial Companion Diagnostic Test

With the advent of targeted therapy in non-small cell lung carcinoma (NSCLC), biomarker detection has become standard practice. US Food and Drug Administration (FDA) has approved a few companion diagnostics as single gene assays to find these driver mutations. We report a case of NSCLC where initial molecular tests to detect epidermal growth factor receptor ( EGFR)- sensitizing mutations by an FDA-approved assay (Cobas® EGFR Mutation Test v2) failed to identify the common EGFR mutation L858R. However, the latter was picked up on subsequent next-generation sequencing (NGS). Interestingly an additional single nucleotide variant K860I was also observed in the cis configuration. The false-negative result for L858R was assumed to be caused by the abrogation of complementarity for the probe binding site on the amplicon generated. The concurrent occurrence of L858R and K860I will not be detectable by Cobas® EGFR Mutation Test v2 (FDA-approved companion diagnostic) despite its real-world intra and inter-laboratory studies demonstrating high accuracy.

The Resistance to EGFR-TKIs in Non-Small Cell Lung Cancer: From Molecular Mechanisms to Clinical Application of New Therapeutic Strategies.

Almost 17% of Western patients affected by non-small cell lung cancer (NSCLC) have an activating epidermal growth factor receptor (EGFR) gene mutation. Del19 and L858R are the most-common ones; they are positive predictive factors for EGFR tyrosine kinase inhibitors (TKIs). Currently, osimertinib, a third-generation TKI, is the standard first-line therapy for advanced NSCLC patients with common EGFR mutations. This drug is also administered as a second-line treatment for those patients with the T790M EGFR mutation and previously treated with first- (erlotinib, gefitinib) or second- (afatinib) generation TKIs. However, despite the high clinical efficacy, the prognosis remains severe due to intrinsic or acquired resistance to EGRF-TKIs. Various mechanisms of resistance have been reported including the activation of other signalling pathways, the development of secondary mutations, the alteration of the downstream pathways, and phenotypic transformation. However, further data are needed to achieve the goal of overcoming resistance to EGFR-TKIs, hence the necessity of discovering novel genetic targets and developing new-generation drugs. This review aimed to deepen the knowledge of intrinsic and acquired molecular mechanisms of resistance to EGFR-TKIs and the development of new therapeutic strategies to overcome TKIs' resistance.