To EGFR-tyrosine Kinase Inhibitors Research Articles

A real‑world study of clinical characteristics, treatment sequence and outcomes of patients with non-small cell lung cancer and EGFR exon 20 insertion mutations.

EGFR exon 20 insertion (EGFRex20ins) mutations are found in up to 4% of all patients with non-small cell lung cancer (NSCLC). These patients are often insensitive to EGFR-tyrosine kinase inhibitors (TKIs) and have worse prognosis than patients with more common EGFR mutations. In this multicenter, retrospective, real-world study, we sought to determine whether the administration of recently approved treatments that specifically target EGFRex20ins mutations could significantly improve outcomes in this patient population. We evaluated the clinical features of 41 patients diagnosed with NSCLC and EGFRex20ins mutations, their evolution, and response to treatments received across 7 hospitals in the Valencian Community, Spain, between 31st December 2012 and 31st December 2022. 32 patients (72%) developed metastatic disease, and 29 (71%) of them received oncological treatment. We found that administering a targeted therapy against EGFRex20ins mutations (amivantamab, mobocertinib and/or sunvozertinib) at some point during the course of treatment, significantly increased the median OS of metastatic patients from 8months (95% CI 0-21.7) to 30months (95% CI 11.1-48.8; Hazard ratio = 0.297, p = 0.02). Our findings contribute to the evolving standard of care for this specific population and highlight the clinical benefits of targeted cancer therapies.

The Comparison of Real-Time PCR and Mutation-Specific Immunohistochemistry in EGFR Mutation Analysis of Non-Small Cell Lung Carcinomas

Objective: This study aims to identify activating mutations in the epidermal growth factor receptor (EGFR) gene in patients with non-small cell lung cancer (NSCLC) and to evaluate their correlation with responses to EGFR-tyrosine kinase inhibitors (TKI) treatment. This study aims to identify activating mutations in the epidermal growth factor receptor (EGFR) gene in patients with non-small cell lung cancer (NSCLC) and to evaluate their correlation with responses to EGFR-tyrosine kinase inhibitors (TKI) treatment. We conducted a comparative analysis of Real-Time PCR and immunohistochemistry to detect EGFR mutation status in non-small cell lung cancer patients, focusing on the sensitivity, specificity, and predictive values of immunohistochemistry. Material and Method: We evaluated 788 non-small cell lung cancer samples which were analyzed for EGFR mutation status by RT-PCR. We detected 126 EGFR mutated cases among these patients. We evaluated mutation-specific EGFR immunohistochemistry directed towards the exon 19 deletions (15 bp E746-A750) and exon 21 point mutation (L858R) to the 47 EGFR mutated patients histologic material and cell blocks of cytologic specimens. Results: 32 of the 47 cases (68%) had exon 19 deletion, 14 of them (30%) had point mutation in exon 21, and one of them (2%) showed exon 18 mutation. EGFR exon 19 (15 bp E746-A750 deletion) antibody showed a sensitivity of 100%, specificity of 40%, negative predictive value of 100%, and positive predictive value of 78%. The sensitivity of the exon 21 (L858R point mutation) antibody was 93%, specificity was 91%, negative predictive value was 97% and positive predictive value was 82%. Conclusion: Our investigation indicates that mutation-specific EGFR immunohistochemistry has demonstrated a notable sensitivity and specificity for exon 21. However, while sensitive, the exon 19 (15 bp E746-A750 deletion) antibody lacked specificity. While positive immunohistochemical staining may suggest the presence of an EGFR mutation, making the patient potentially eligible for TKI treatment, it should not be the sole determinant. If immunohistochemistry results are negative, it is essential to resort to molecular tests to ensure accurate diagnosis and appropriate therapeutic guidance. With evolving diagnostic landscapes, it is crucial to harness both IHC and molecular techniques judiciously for optimal patient care.

Potential Utility of a 4th-Generation EGFR-TKI and Exploration of Resistance Mechanisms-An In Vitro Study.

The emergence of acquired resistance to EGFR-tyrosine kinase inhibitors (TKIs) is almost inevitable even after a remarkable clinical response. Secondary mutations such as T790M and C797S are responsible for the resistance to 1st/2nd-generation (1/2G) TKIs and 3G TKIs, respectively. To overcome both the T790M and C797S mutations, novel 4G EGFR-TKIs are now under early clinical development. In this study, we evaluated the efficacy of a 4G EGFR-TKI in the treatment of lung cancer with EGFR mutation as well as explored resistance mechanisms to a 4G TKI. First, we compared the efficacies of seven TKIs including a 4G TKI, BI4020, against Ba/F3 cell models that simulate resistant tumors after front-line osimertinib treatment failure because of a secondary mutation. We also established acquired resistant cells to BI4020 by chronic drug exposure. Ba/F3 cells with an osimertinib-resistant secondary mutation were refractory to all 3G TKIs tested (alflutinib, lazertinib, rezivertinib, almonertinib, and befotertinib). BI4020 inhibited the growth of C797S-positive cells; however, it was not effective against L718Q-positive cells. Erlotinib was active against all Ba/F3 cells tested. In the analysis of resistance mechanisms of BI4020-resistant (BIR) cells, none harbored secondary EGFR mutations. HCC827BIR cells had MET gene amplification and were sensitive to a combination of capmatinib (MET-TKI) and BI4020. HCC4006BIR and H1975BIR cells exhibited epithelial-to-mesenchymal transition. This study suggests that erlotinib may be more suitable than 4G TKIs to overcome secondary mutations after front-line osimertinib. We found that off-target mechanisms that cause resistance to earlier-generation TKIs will also cause resistance to 4G TKIs.

GLUT1 promotes cell proliferation via binds and stabilizes phosphorylated EGFR in lung adenocarcinoma

BackgroundWhile previous studies have primarily focused on Glucose transporter type 1 (GLUT1) related glucose metabolism signaling, we aim to discover if GLUT1 promotes tumor progression through a non-metabolic pathway.MethodsThe RNA-seq and microarray data were comprehensively analyzed to evaluate the significance of GLUT1 expression in lung adenocarcinoma (LUAD). The cell proliferation, colony formation, invasion, and migration were used to test GLUT1 ‘s oncogenic function. Co-immunoprecipitation and mass spectrum (MS) were used to uncover potential GLUT1 interacting proteins. RNA-seq, DIA-MS, western blot, and qRT-PCR to probe the change of gene and cell signaling pathways.ResultsWe found that GLUT1 is highly expressed in LUAD, and higher expression is related to poor patient survival. GLUT1 knockdown caused a decrease in cell proliferation, colony formation, migration, invasion, and induced apoptosis in LUAD cells. Mechanistically, GLUT1 directly interacted with phosphor-epidermal growth factor receptor (p-EGFR) and prevented EGFR protein degradation via ubiquitin-mediated proteolysis. The GLUT1 inhibitor WZB117 can increase the sensitivity of LUAD cells to EGFR-tyrosine kinase inhibitors (TKIs) Gefitinib.ConclusionsGLUT1 expression is higher in LUAD and plays an oncogenic role in lung cancer progression. Combining GLUT1 inhibitors and EGFR-TKIs could be a potential therapeutic option for LUAD treatment.

Clinical-genomic characteristics in patients with EGFR-mutated non-small cell lung cancer harboring MET copy number gains after progression on EGFR-TKI: A report from LC-SCRUM-TRY.

8628 Background: MET amplification (amp) account for 10-15% of resistance mechanism in EGFR-mutated non-small cell lung cancer (NSCLC) to EGFR-tyrosine kinase inhibitor (TKI) treatment. MET copy number (CN) gains consists of MET focal amp and polysomy (poly), but the clinical characteristics and outcome of EGFR-TKI resistant NSCLC patients harboring MET amp, poly remains unclear. Methods: The clinical-genomic characteristics and treatment outcome ofEGFR-TKI resistant EGFR-mutated NSCLC registered in LC-SCRUM-TRY (UMIN000041957) were analyzed. Genetic resistant alterations were screened using next-generation sequencing (NGS) (Tissue; Oncomine Precision Assay [OPA] or Plasma; Guardant360 [G360]), and MET-fluorescence in-situ hybridization (FISH). MET amp was defined as MET CN ≥4 (OPA), MET CN ≥2.12 (G360) or MET/CEP7 ratio ≥2 (FISH). MET poly was defined as MET CN≥5 and MET/CEP7 ratio <2 by FISH. Results: A total of 1559 patients had been enrolled in LC-SCRUM-TRY between Sep 2020 and Jan 2024. Of 1537 analyzed samples, 666 (43%) were EGFR-TKI resistant samples. Of these, 92 (14%), 239 (36%) and 335 (50%) had MET amp, poly, and no CN gain (no CNG), respectively. Patient characteristics and treatment outcome with 1st line EGFR-TKI and platinum-based chemotherapy (PBC) post EGFR-TKI is summarized (Table 1). The overall response rate (ORR) of PBC post EGFR-TKI in the patients with MET amp, poly and no CNG was 41%, 29% and 31%, respectively (p=0.34), with median progression-free survival (mPFS) being 5.7 months, 6.8 months, and 6.7 months (p=0.02). In addition, 12 and 11 of patients with MET amp and poly were enrolled into clinical trial of MET-targeted therapy (MET-TKI, n=2; MET-antibody-drug conjugate [ADC], n=4; EGFR/MET-antibody, n=2), and MET non-targeted therapy (EGFR-TKI, n=5; other ADCs, n=10: immunotherapy; n=1). The ORR of MET-targeted therapy/MET non-targeted therapy were 60/0% for MET amp, and 0/33% for MET poly, respectively. Conclusions: Patients with shorter PFS with prior 1st line EGFR-TKI are more likely to have MET amp. The efficacy of standard PBC post EGFR-TKI in patients with MET CNG is limited. Current MET-targeted therapy may not be effective for EGFR-mutated NSCLC harboring MET poly after progression on EGFR-TKI. [Table: see text]

Leucine Zipper Downregulated in Cancer-1 Interacts with Clathrin Adaptors to Control Epidermal Growth Factor Receptor (EGFR) Internalization and Gefitinib Response in EGFR-Mutated Non-Small Cell Lung Cancer.

The epidermal growth factor receptor (EGFR) is a common driver of non-small cell lung cancer (NSCLC). Clathrin-mediated internalization (CMI) sustains EGFR signaling. AXL is associated with resistance to EGFR-tyrosine kinase inhibitors (TKIs) in EGFR-mutated (EGFRM) NSCLC. We investigated the effects of Leucine zipper downregulated in cancer-1 (LDOC1) on EGFR CMI and NSCLC treatment. Coimmunoprecipitation, double immunofluorescence staining, confocal microscopy analysis, cell surface labelling assays, and immunohistochemistry studies were conducted. We revealed that LDOC1 interacts with clathrin adaptors through binding motifs. LDOC1 depletion promotes internalization and plasma membrane recycling of EGFR in EGFRM NSCLC PC9 and HCC827 cells. Membranous and cytoplasmic EGFR decreased and increased, respectively, in LDOC1 (-) NSCLC tumors. LDOC1 depletion enhanced and sustained activation of EGFR, AXL, and HER2 and enhanced activation of HER3 in PC9 and HCC827 cells. Sensitivity to first-generation EGFR-TKIs (gefitinib and erlotinib) was significantly reduced in LDOC1-depleted PC9 and HCC827 cells. Moreover, LDOC1 downregulation was significantly associated (p < 0.001) with poor overall survival in patients with EGFRM NSCLC receiving gefitinib (n = 100). In conclusion, LDOC1 may regulate the efficacy of first-generation EGFR-TKIs by participating in the CMI of EGFR. Accordingly, LDOC1 may function as a prognostic biomarker for EGFRM NSCLC.

4″-Alkyl EGCG Derivatives Induce Cytoprotective Autophagy Response by Inhibiting EGFR in Glioblastoma Cells.

Epidermal growth factor receptor (EGFR)-targeted therapy has been proven vital in the last two decades for the treatment of multiple cancer types, including nonsmall cell lung cancer, glioblastoma, breast cancer and head and neck squamous cell carcinoma. Unfortunately, the majority of approved EGFR inhibitors fall into the drug resistance category because of continuous mutations and acquired resistance. Recently, autophagy has surfaced as one of the emerging underlying mechanisms behind resistance to EGFR-tyrosine kinase inhibitors (TKIs). Previously, we developed a series of 4″-alkyl EGCG (4″-Cn EGCG, n = 6, 8, 10, 12, 14, 16, and 18) derivatives with enhanced anticancer effects and stability. Therefore, the current study hypothesized that 4″-alkyl EGCG might induce cytoprotective autophagy upon EGFR inhibition, and inhibition of autophagy may lead to improved cytotoxicity. In this study, we have observed growth inhibition and caspase-3-dependent apoptosis in 4″-alkyl EGCG derivative-treated glioblastoma cells (U87-MG). We also confirmed that 4″-alkyl EGCG could inhibit EGFR in the cells, as well as mutant L858R/T790M EGFR, through an in vitro kinase assay. Furthermore, we have found that EGFR inhibition with 4″-alkyl EGCG induces cytoprotective autophagic responses, accompanied by the blockage of the AKT/mTOR signaling pathway. In addition, cytotoxicity caused by 4″-C10 EGCG, 4″-C12 EGCG, and 4″-C14 EGCG was significantly increased after the inhibition of autophagy by the pharmacological inhibitor chloroquine. These findings enhance our understanding of the autophagic response toward EGFR inhibitors in glioblastoma cells and suggest a potent combinatorial strategy to increase the therapeutic effectiveness of EGFR-TKIs.

Machine learning-based radiomics strategy for prediction of acquired EGFR T790M mutation following treatment with EGFR-TKI in NSCLC

The epidermal growth factor receptor (EGFR) Thr790 Met (T790M) mutation is responsible for approximately half of the acquired resistance to EGFR-tyrosine kinase inhibitor (TKI) in non-small-cell lung cancer (NSCLC) patients. Identifying patients at diagnosis who are likely to develop this mutation after first- or second-generation EGFR-TKI treatment is crucial for better treatment outcomes. This study aims to develop and validate a radiomics-based machine learning (ML) approach to predict the T790M mutation in NSCLC patients at diagnosis. We collected retrospective data from 210 positive EGFR mutation NSCLC patients, extracting 1316 radiomics features from CT images. Using the LASSO algorithm, we selected 10 radiomics features and 2 clinical features most relevant to the mutations. We built models with 7 ML approaches and assessed their performance through the receiver operating characteristic (ROC) curve. The radiomics model and combined model, which integrated radiomics features and relevant clinical factors, achieved an area under the curve (AUC) of 0.80 (95% confidence interval [CI] 0.79–0.81) and 0.86 (0.87–0.88), respectively, in predicting the T790M mutation. Our study presents a convenient and noninvasive radiomics-based ML model for predicting this mutation at the time of diagnosis, aiding in targeted treatment planning for NSCLC patients with EGFR mutations.

Combined radiomics of primary tumour and bone metastasis improve the prediction of EGFR mutation status and response to EGFR-TKI therapy for NSCLC

PurposeTo develop radiomics models of primary tumour and spinal metastases to predict epidermal growth factor receptor (EGFR) mutations and therapeutic response to EGFR-tyrosine kinase inhibitor (TKI) in patients with metastatic non-small-cell lung cancer (NSCLC). MethodsWe enrolled 203 patients with spinal metastases between December 2017 and September 2021, classified as patients with the EGFR mutation or EGFR wild-type. All patients underwent thoracic CT and spinal MRI scans before any treatment. Radiomics analysis was performed to extract features from primary tumour and metastases images and identify predictive features with the least absolute shrinkage and selection operator. Radiomics signatures (RS) were constructed based on primary tumour (RS-Pri), metastases (RS-Met), and in combination (RS-Com) to predict EGFR mutation status and response to EGFR-TKI. Receiver operating characteristic (ROC) curve analysis with 10-fold cross-validation was applied to assess the performance of the models. ResultsTo predict the EGFR mutation status, the RS based on the combination of primary tumour and metastases improved the prediction AUCs compared to those based on the primary tumour or metastasis alone in the training (RS-Com-EGFR: 0.927) and validation (RS-Com-EGFR: 0.812) cohorts. To predict response to EGFR-TKI, the developed RS based on combined primary tumour and metastasis generated the highest AUCs in the training (RS-Com-TKI: 0.880) and validation (RS-Com-TKI: 0.798) cohort. ConclusionsPrimary NSCLC and spinal metastases can provide complementary information to predict the EGFR mutation status and response to EGFR-TKI. The developed models that integrate primary lesions and metastases may be potential imaging markers to guide individual treatment decisions.

Thyroid transcription factor 1 (TTF-1) negativity as a predictor of unfavorable response to EGFR-TKI therapy in advanced lung adenocarcinoma patients with EGFR mutations.

The absence of thyroid transcription factor 1 (TTF-1) is associated with a lower frequency of epidermal growth factor receptor (EGFR) mutations in lung adenocarcinoma (LUAD). The aim of this study was to assess the impact of TTF-1 expression on the clinical response to EGFR-tyrosine kinase inhibitor (TKI) treatment in patients with advanced LUAD. The data of patients with advanced LUAD who were admitted to the Beijing Tiantan Hospital and Peking University Cancer Hospital (China) between April 2009 and May 2023 was retrospectively analyzed. A total of 227 patients diagnosed with advanced LUAD were included, of which 28.2% (64/227) had TTF-1-negative adenocarcinoma, while 54.6% (124/227) harbored EGFR mutations. Negative TTF-1 expression significantly correlated with male sex (68.8% vs. 42.3%, p < 0.001), history of heavy smoking (57.8% vs. 36.2%, p = 0.003), poorly differentiated tumors (86.5% vs. 43.2%, p < 0.001), and lower frequency of EGFR mutations (26.6% vs. 65.6%, p < 0.001) compared with TTF-1 positivity. Multivariable logistic regression showed that low prevalence of EGFR mutations (p < 0.001) and male sex (p = 0.006) were independent predictive factors for the negative expression of TTF-1. Patients lacking TTF-1 also exhibited worse overall response rate (ORR; 23.5% vs. 54.2%, p = 0.019), disease control rate (DCR; 58.8% vs. 89.7%, p = 0.003), and median progression-free survival (PFS; 2.9 vs. 11.6 months, p < 0.001) following treatment with EGFR-TKIs compared to the TTF-1-positive patients with EGFR mutations. Patients with TTF-1-negative and EGFR-mutant LUAD show a diminished response to EGFR-TKIs.

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

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

Brain-Tumor Interface-Based MRI Radiomics Models to Determine EGFR Mutation, Response to EGFR-TKI and T790M Resistance Mutation in Non-Small Cell Lung Carcinoma Brain Metastasis.

Preoperative assessment of epidermal growth factor receptor (EGFR) status, response to EGFR-tyrosine kinase inhibitors (TKI) and development of T790M mutation in non-small cell lung carcinoma (NSCLC) patients with brain metastases (BM) is important for clinical decision-making, while previous studies were only based on the whole BM. To investigate values of brain-to-tumor interface (BTI) for determining the EGFR mutation, response to EGFR-TKI and T790M mutation. Retrospective. Two hundred thirty patients from Hospital 1 (primary cohort) and 80 patients from Hospital 2 (external validation cohort) with BM and histological diagnosis of primary NSCLC, and with known EGFR status (biopsy) and T790M mutation status (gene sequencing). Contrast-enhanced T1-weighted (T1CE) and T2-weighted (T2W) fast spin echo sequences at 3.0T MRI. Treatment response to EGFR-TKI therapy was determined by the Response Evaluation Criteria in Solid Tumors. Radiomics features were extracted from the 4 mm thickness BTI and selected by least shrinkage and selection operator regression. The selected BTI features and volume of peritumoral edema (VPE) were combined to construct models using logistic regression. The performance of each radiomics model was evaluated using the area under the receiver operating characteristic (ROC) curve (AUC). A total of 7, 3, and 3 features were strongly associated with the EGFR mutation status, response to EGFR-TKI and T790M mutation status, respectively. The developed models combining BTI features and VPE can improve the performance than those based on BTI features alone, generating AUCs of 0.814, 0.730, and 0.774 for determining the EGFR mutation, response to EGFR-TKI and T790M mutation, respectively, in the external validation cohort. BTI features and VPE were associated with the EGFR mutation status, response to EGFR-TKI and T790M mutation status in NSCLC patients with BM. 3 Technical Efficacy: Stage 2.

Abstract 2660: HMBD-501 - a novel Fc engineered, exatecan-based next generation HER3 targeting antibody drug conjugate shows robust efficacy and tolerability in pre-clinical solid tumor models

Abstract HER3 is a member of the epidermal growth factor receptor (ERBB) family of tyrosine kinase receptors overexpressed in a broad range of tumors and is associated with disease progression and poor survival. For example, more than 50% of melanoma, cervical, lung, gastric, colorectal, and ovarian cancers show overexpression of HER3, while in breast, pancreatic and prostate cancers the overexpression ranges between 25-40%. In addition, recent studies show that HER3 expression is significantly induced in tumors during metastasis (in colorectal) and during acquired resistance to tyrosine kinase inhibitors (TKI) in lung cancers. This widespread overexpression of HER3 makes it an ideal target for antibody drug conjugates (ADCs). ADCs are a therapeutic modality that harness an antibody’s target specificity to selectively deliver cytotoxic payloads to tumors. Patritumab-Deruxtecan (U3-1402), a HER3-targeting ADC, showed clinical response in a subset of EGFR mutant and TKI resistant lung cancers in a Phase 1 study, albeit with toxicities including severe interstitial lung disease (ILD) and high grade cytopenias. Mechanistic studies show that these ADC-related toxicities are likely driven by Fc- or micropinocytosis-mediated uptake of ADCs by normal cells. We have developed HMBD-501, a novel anti-HER3 ADC with (i) a high-affinity Fab, which can bind to HER3 in the presence or absence of its ligand NRG1, (ii) an engineered Fc-domain to avoid FcgR binding and potential toxicities, and (iii) site-specific conjugation to a next generation cleavable linker and exatecan-based payload. In our preclinical studies, HMBD-501 demonstrates superior inhibition of tumor growth compared to other exatecan-based anti-HER3 ADCs, in a variety of in vitro and in vivo cancer models with a range of HER3 expression. Additionally, the optimized Fc engineering of HMBD-501 shows enhanced tolerability in vivo indicating a potential reduction in Fc mediated toxicities. Finally, the next generation site-specific conjugation-linker-payload technology of HMBD-501 allows optimal plasma stability and pharmacokinetic profile. In conclusion, HMBD-501 represents a next generation HER3 targeting ADC that has a potentially best-in-class efficacy and tolerability profile. Our findings strongly support the development of HMBD-501 as a promising candidate in the treatment of HER3 expressing solid tumors. Citation Format: Suhail Ahmed Kabeer Rasheed, Dipti Thakkar, Shalini Paliwal, Wen Jie Chin, Akshaya Bansal, Ben Ayers, Che Theng ng, Brendon Hanson, Piers Ingram, Jerome Boyd-Kirkup. HMBD-501 - a novel Fc engineered, exatecan-based next generation HER3 targeting antibody drug conjugate shows robust efficacy and tolerability in pre-clinical solid tumor models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2660.

A high number of co-occurring genomic alterations detected by NGS is associated with worse clinical outcomes in advanced EGFR-mutant lung adenocarcinoma: Data from LATAM population

BackgroundCo-occurring genomic alterations identified downstream main oncogenic drivers have become more evident since the introduction of next-generation sequencing (NGS) analyses at diagnosis and progression. Emerging evidence has stated that co-occurring genomic alterations at diagnosis might represent de novo and primary resistance mechanisms to tyrosine kinase inhibitors (TKIs) in advanced EGFR-mutant (EGFRm) non-small lung cancer (NSCLC). In this study, we assessed the prognostic role of co-occurring genomic alterations in advanced EGFRm NSCLC. MethodsA cohort of 111 patients with advanced NSCLC harboring EGFR-sensitive mutations detected by PCR was analyzed in 5 Latin American oncological centers from January 2019 to December 2020. All eligible patients received upfront therapy with EGFR-TKI. Co-occurring genomic alterations were determined at diagnosis in every patient by the NGS (FoundationOneCDx) comprehensive platform, which evaluates 324 known cancer-related genes. ResultsEGFR exon19 deletion was the most frequent oncogenic driver mutation (60.4 %) detected by NGS. According to the NGS assay, 31 % and 68.3 % of patients had 1–2 and ≥ 3 co-occurring genomic alterations, respectively. The most frequent co-occurring genomic alterations were TP53 mutations (64.9 %) followed by CDKN2AB alterations (13.6 %), BRCA2 (13.6 %), and PTEN (12.7 %) mutations. Baseline central nervous system disease was present in 42.7 % of patients. First- or second-generation EGFR TKIs (gefitinib, afatinib, or erlotinib) were the most common treatment in 67.5 % of patients, while osimertinib was administered in 27.9 % of cases. The median PFS in all evaluated patients was 13.63 months (95 %CI: 11.79–15.52). Using ≥ 3 co-occurring alterations as the cut-off point, patients with ≥ 3 co-occurring genomic alterations showed a median PFS, of 12.7 months (95 %CI: 9.92–15.5) vs 21.3 months (95 %CI: 13.93-NR) in patients with 2 or less co-occurring genomic alterations [HR 3.06, (95 %CI: 1.55–5.48) p = 0.0001]. Also, patients with a TP53 mutation had a shorter PFS, 13.6 (95 %CI: 10.7–15.5) vs 19.2 months (95 %CI: 12.8-NR); in wild type TP53 [HR 2.01 (95 %CI: 1.18–3.74) p = 0.12]. In the multivariate analysis, the number (≥3) of concurrent genomic alterations and ECOG PS of 2 or more were related to a significant risk factor for progression [HR 2.79 (95 %CI: 1.49–5.23) p = 0.001 and HR 2.42 (95 %CI: 1.22–4.80) p = 0.011 respectively]. ConclusionEGFR-mutant NSCLC is not a single oncogene-driven disease in the majority of cases, harboring a higher number of co-occurring genomic alterations. This study finds the number of co-occurring genomic alterations and the presence of TP53 mutations as negative prognostic biomarkers, which confers potentially earlier resistance mechanisms to target therapy.

Radiomics for prediction of response to EGFR-TKI based on metastasis/brain parenchyma (M/BP)-interface.

To evaluate the potential of subregional radiomics as a novel tumor marker in predicting epidermal growth factor receptor (EGFR) mutation status and response to EGFR-tyrosine kinase inhibitor (TKI) therapy in NSCLC patients with brain metastasis (BM). We included 230 patients from center 1, and 80 patients were included from center 2 to form a primary and external validation cohort, respectively. Patients underwent contrast-enhanced T1-weighted and T2-weighted MRI scans before treatment. The individual- and population-level clustering was used to partition the peritumoral edema area (POA) into phenotypically consistent subregions. Radiomics features were calculated and selected from the tumor active area (TAA), POA and subregions, and used to develop models. Prediction values of each region were investigated and compared with receiver operating characteristic curves and Delong test. For predicting EGFR mutations, a multi-region combined model (EGFR-Fusion) was developed based on joint of the partitioned metastasis/brain parenchyma (M/BP)-interface and TAA, and generated the highest prediction performance in the training (AUC = 0.945, SEN = 0.878, SPE = 0.937), internal validation (AUC = 0.880, SEN = 0.733, SPE = 0.969), and external validation (AUC = 0.895, SEN = 0.875, SPE = 0.800) cohorts. For predicting response to EGFR-TKI, the developed multi-region combined model (TKI-Fusion) yielded predictive AUCs of 0.869 (SEN = 0.717, SPE = 0.884), 0.786 (SEN = 0.708, SPE = 0.818), and 0.802 (SEN = 0.750, SPE = 0.800) in the training, internal validation and external validation cohort, respectively. Our study revealed that complementary information regarding the EGFR status and response to EGFR-TKI can be provided by subregional radiomics. The proposed radiomics models may be new markers to guide treatment plans for NSCLC patients with BM.

Advances in ICIs Therapy after TKIs Resistance in Patients with EGFR Mutant NSCLC: A Review

表皮生长因子受体酪氨酸激酶抑制剂（epidermal growth factor receptor-tyrosine kinase inhibitors, EGFR-TKIs）耐药后的EGFR突变晚期非小细胞肺癌（non-small cell lung cancer, NSCLC）患者的后续治疗已成为目前的热点和难点。免疫检查点抑制剂（immune checkpoint inhibitors, ICIs）治疗对于这部分患者来说是一个崭新而重要的选择，然而众多研究却显示疗效差强人意。但同时，国内外也有研究表明部分驱动基因阳性且靶向治疗耐药后的患者接受ICIs联合治疗仍显效。那么，在免疫治疗时代，不同的患者接受不同的ICIs联合策略的疗效有何差异？影响疗效的因素有哪些？这些因素与其他免疫治疗疗效预测标志物的内在联系有哪些？这些问题都有着广阔而重要的研究价值。

Abstract 5335: Elucidation of initial resistance mechanisms in EGFR mutation-positive lung cancer focusing on YAP1 and cancer stem cells

Abstract Background: EGFR mutation-positive lung cancer has high response rates to EGFR-tyrosine kinase inhibitors (TKIs), but eventually acquires resistance to EGFR-TKIs. Acquired resistance mechanisms are diverse because of tumor heterogeneity, which makes it difficult to overcome acquired resistance. Initial resistance is the resistance mechanism of tumor cells that survive the initial treatment. If we could overcome the initial resistance, we could prevent cancer cells from developing various types of acquired resistance. We are now focusing on YAP1 and cancer stem cells, which have been also reported as acquired resistance mechanisms in various types of cancers. Methods: PC-9 cells and HCC827 cells which were EGFR mutation-positive lung cancer cell lines were mainly utilized in our experiments; they were purchased from ECACC and ATCC, respectively. We mainly utilized osimertinib as an EGFR-TKI and verteporfin as a YAP1 inhibitor. The nuclear translocation of YAP1 was confirmed by fluorescence immunostaining. siRNA was utilized to knock down YAP1. Cell viability assays were performed using CellTiter-Glo reagent. qRT-PCR was performed to confirm the gene expression of cancer stem cells. Results: YAP1 is activated by nuclear translocation. In PC-9 cells, YAP1 was localized in the nucleus after osimertinib exposure. In contrast, YAP1 was localized in the nucleus of HCC827 cells before osimertinib exposure and remained in the nucleus even after osimertinib exposure. These data suggest that YAP1 activation is correlated with initial resistance. Cell viability assay showed that both PC-9 cells and HCC827 cells became more sensitive to osimertinib with the knocking down of YAP1. In addition, cell viability assays using PC-9 cells with verteporfin and osimertinib showed increased sensitivity to osimertinib. The gene expression of ALDH1A1 and SOX2 which are involved in cancer stem cells were increased in PC-9 cells after osimertinib exposure. On the other hand, the gene expression of ALDH1A1 was up-regulated but SOX2 was down-regulated in HCC827 cells after osimertinib exposure. We hypothesized that increased gene expression of cancer stem cells occurred downstream of YAP1 followed by initial resistance, thus we are currently confirming the gene alteration of cancer stem cells associated with osimertinib exposure with the knocking down YAP1. We are also considering the investigation of combination therapy of EGFR-TKIs and YAP1 inhibitors in vivo studies. Conclusions: YAP1 and cancer stem cells may be involved in initial resistance mechanisms to EGFR-TKIs in EGFR mutation-positive lung cancer. Our results suggest that especially YAP1 can be a potential therapeutic target, thus we will continue additional studies of combination therapy of EGFR-TKIs and YAP1 inhibitors. In addition, we will continue to investigate whether the gene for cancer stem cells acts downstream of YAP1. Citation Format: Tatsuya Ogimoto, Hiroaki Ozasa, Kentaro Hashimoto, Hiroshi Yoshida, Kazutaka Hosoya, Masatoshi Yamazoe, Hitomi Ajimizu, Tomoko Funazo, Takahiro Tsuji, Hironori Yoshida, Ryo Itotani, Yuichi Sakamori, Toyohiro Hirai. Elucidation of initial resistance mechanisms in EGFR mutation-positive lung cancer focusing on YAP1 and cancer stem cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5335.

Abstract 3259: TAS3351 is a 4th-generation EGFR-TKI overcoming T790M and C797S-mediated resistance in NSCLC with EGFR common mutations

Abstract Background: Common mutations (exon 19 deletion; ex19del or L858R point mutation; L858R) of the epidermal growth factor receptor (EGFR) are found in patients with non-small cell lung cancer (NSCLC) and are sensitive to EGFR-tyrosine kinase inhibitors (TKIs), including osimertinib, a third-generation, irreversible EGFR-TKI. Although osimertinib is widely utilized as the standard of care in first-line therapy of NSCLC, resistance inevitably occurs during the treatment. Among EGFR-dependent/on-target resistant mechanisms of osimertinib, the C797S mutation is reported to emerge as the most frequent alteration. The cysteine residue at position 797 of EGFR is covalently bound with osimertinib, and its alteration to serine causes an inability to form a covalent bond, making osimertinib resistant to NSCLC with a C797S mutation. While first-generation, reversible EGFR-TKIs (gefitinib and erlotinib) might be effective for patients with C797S mutation, the T790M mutation is reported to emerge in almost half of patients with EGFR common mutations during treatment with first-generation EGFR-TKIs. Here, we report TAS3351 as a novel, next-generation EGFR-TKI designed to overcome C797S and T790M-mediated resistance in NSCLC patients. Methods: The inhibitory potency of TAS3351 on cellular phospho-EGFR was analyzed by In-cell western assay. In addition, inhibition of cell viability in Ba/F3 cells transformed by human wild type or mutated EGFR, as well as in human NSCLC cell lines whose EGFR harbors common mutations, was tested. Anti-tumor activity of TAS3351 was evaluated in NIH/3T3-EGFR allograft models and human NSCLC xenograft models. Results: TAS3351 exhibited almost comparable inhibitory potency against cellular phosphorylation of EGFR harboring ex19del or L858R with or without C797S and/or T790M while sparing wild type EGFR activity. TAS3351 also showed similar trends in the cell viability assay for Ba/F3-EGFR cells and human NSCLC cell lines. Finally, TAS3351 demonstrated favorable anti-tumor activity in NIH/3T3 allografts transformed by human EGFR harboring ex19del/C797S/T790M. Conclusion: TAS3351 is a fourth-generation EGFR-TKI overcoming T790M and C797S-mediated resistance in NSCLC with common mutations. The present results support the clinical development of TAS3351 as monotherapy in NSCLC patients with EGFR mutations harboring C797S and/or T790M EGFR-TKI resistance mutations. Citation Format: Hidefumi Kasuga, Yuki Kataoka, Fuyuki Yamamoto, Takashi Mizutani, Shingo Tsuji, Sakiho Tanaka, Shinji Mizuarai. TAS3351 is a 4th-generation EGFR-TKI overcoming T790M and C797S-mediated resistance in NSCLC with EGFR common mutations [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3259.

The efficacy and prognostic factors of immunotherapy in advanced non-small cell lung cancer patients with different driver gene mutations

Objective: To explore the efficacy and prognostic factors of immunotherapy in advanced non-small cell lung cancer (NSCLC) patients with different driver gene mutations. Methods: Medical records of advanced NSCLC patients who harbored driver gene mutations (EGFR, KRAS, ALK and etc.) and received PD-1 inhibitors in Henan Cancer Hospital from April 2016 to May 2021 were collected. Treatment patterns, progression free survival (PFS), overall survival (OS) and prognostic factors of patients with driver gene mutations were estimated. Results: A total of 120 patients were included. There were 70 males and 50 females, with a median age [M(Q1,Q3)] of 57 (50, 65) years. Of these, 52 patients harbored KRAS mutations, 42 patients harbored EGFR mutations, 16 patients harbored ERBB2 mutations, 5 patients harbored MET mutations or amplifications, 5 patients harbored ROS-1 mutations, 2 patients harbored BRAF mutations, and the last 2 patients harbored ALK and RET mutations, respectively. The PFS and OS [M (95%CI)] were 6.4 (5.1-7.8) and 31.2 (22.0-40.3) months in 120 participated patients. Patients with KRAS mutations showed the greatest survival benefit from Immune checkpoint inhibitors (ICIs) with the PFS of 9.7 (4.8-14.6) months and OS of 31.2 (19.4-50.6) months. They mostly received the first-line (34.6%, 18/52) and second-line (38.5%, 20/52) ICIs. The PFS and OS of EGFR mutant patients were 3.9 (1.8-6.1) months and 18.0 (12.1-23.8) months, respectively. They tended to receive ICIs after resistance to EGFR-tyrosine kinase inhibitors (TKIs), and the proportion of second-, third-, fourth or further-line drugs was 38.1% (16/42), 11.9% (5/42), and 47.6% (20/42), respectively. PD-L1 expression level (negative vs ≥50% positive: HR=3.710, 95%CI: 1.372-10.031, P=0.010; 1%-49% positive vs ≥50% positive: HR=2.738, 95%CI: 0.841-8.912, P=0.094), age (every additional year: HR=0.957, 95%CI: 0.933-0.982, P=0.001) and different driver mutations status (EGFR vs KRAS: HR=2.676, 95%CI: 1.317-5.436, P=0.006; ERBB2 vs KRAS: HR=3.411, 95%CI: 1.493-7.792, P=0.004; other mutations vs KRAS: HR=0.727, 95%CI: 0.322-1.643, P=0.444) were prognostic factors for PFS. While PD-L1 expression level (negative vs ≥50% positive: HR=2.305, 95%CI: 0.748-7.103, P=0.146; 1%-49% positive vs ≥50% positive: HR=1.286, 95%CI: 0.337-4.913, P=0.713), and treatment lines of ICIs (first-line vs ≥ third-line: HR=0.322, 95%CI: 0.114-0.914, P=0.033; second-line vs ≥ third-line: HR=0.375, 95%CI: 0.178-0.789, P=0.010) were prognostic factors for OS. Conclusions: KRAS mutant NSCLC patients mostly receive ICIs at the front line, and have best survival benefits from immunotherapy. While EGFR mutant NSCLC patients tend to receive ICIs at the back line, and obtain reasonable survival benefits. PD-L1 expression level, age, and different driver mutations status are prognostic factors for PFS, and PD-L1 expression level and treatment lines of ICIs are prognostic factors for OS.

Immunological effect of tyrosine kinase inhibitors on the tumor immune environment in non-small cell lung cancer.

Acquired resistance to tyrosine kinase inhibitors (TKIs) limits the duration of antitumor effects and impairs the survival of patients with oncogene-driven non-small cell lung cancer (NSCLC). At present, little is known about the immunomodulatory ability of TKIs during the entire treatment period, including the drug-sensitive and drug-resistant periods. The present review aimed to comprehensively explore the dynamic changes in the tumor microenvironment (TME) during TKI treatment in NSCLC. Previous clinical and preclinical studies from medical and health databases related to NSCLC are reviewed. During the response period, cytotoxic immune cells accumulate in the TME and contribute to the formation of an inflammatory microenvironment. During the resistance period, the number of immunosuppressive cells increases, as does the expression of immune checkpoint proteins, which are critical mechanisms for tumor progression. The combination of targeted therapy and immunotherapy has been explored in multiple studies, and preliminary data showed controversial results. Extensive studies are needed to confirm the criteria of the selected patient subgroups and the toxicity profiles of EGFR TKIs and immune checkpoint inhibitors (ICIs). At present, the reagents targeting other immune cells, cytokines and related pathways remain underexplored compared with the revolutionary effect of ICIs in lung cancer. In the future, the precisely selected regimens for combination treatment should be further investigated in carefully designed xenograft models and clinical trials.