Epidermal Growth Factor Receptor To Tyrosine Kinase Inhibitors Research Articles

Clinical and molecular profiling of EGFR-mutant lung adenocarcinomas transformation to small cell lung cancer during TKI treatment.

Small cell lung cancer (SCLC) transformation serves as a significant mechanism of resistance to tyrosine kinase inhibitors (TKIs) in advanced non-small cell lung cancer (NSCLC) with epidermal growth factor receptor (EGFR) mutations. To address this clinical challenge, we conducted a retrospective analysis at Zhejiang University School of Medicine, the First Affiliated Hospital, focusing on patients with EGFR sensitizing mutations. A total of 1012 cases were included in this retrospective analysis. The cohort primarily consisted of patients with EGFR sensitizing mutations. Biopsy-confirmed small cell transformation was observed in seven patients, accounting for 0.7% of the cases. All patients in this subset were initially diagnosed with stage IV adenocarcinoma (ADC), with four cases classified as poorly differentiated and three as moderately to poorly differentiated ADC. EGFR exon 19 deletions were identified in five of these cases. Next-generation sequencing (NGS) was performed on seven cases, revealing mutations in the tumor protein p53 (TP53) gene in four cases and loss of the retinoblastoma1 (RB1) gene in three cases. The median duration from the initial diagnosis to small cell transformation was 35.9 months (interquartile range: 12.1-84 months). Following small cell transformation during EGFR inhibition, all patients received etoposide/platinum-based treatment, leading to a median progression-free survival (PFS) of 4.7 months (interquartile range: 2.7-10.1 months). Notably, most patients in this series had poorly differentiated adenocarcinomas at the outset. TP53 mutations and RB1 loss were common genetic alterations observed in patients with small cell transformation in this cohort. The findings underscore the clinical significance of SCLC transformation as a resistance mechanism to EGFR TKIs in NSCLC with EGFR mutations. The observed genetic alterations, including TP53 mutations and RB1 loss, suggest potential associations with the transformation process and warrant further investigation. Understanding the genetic landscape and clinical outcomes in patients experiencing small cell transformation can contribute to improved strategies for managing resistance in EGFR-mutant NSCLC.

The Lifted Veil of Uncommon EGFR Mutation p.L747P in Non-Small Cell Lung Cancer: Molecular Feature and Targeting Sensitivity to Tyrosine Kinase Inhibitors

ObjectivesThe uncommon p.L747P mutation in epidermal growth factor receptor (EGFR) exon 19 reveals to alter the response to tyrosine kinase inhibitors (TKIs) in patients diagnosed with advanced non-small cell lung cancer (NSCLC). However, the underlying mechanism is still not clear. This study aimed to investigate the clinical outcomes, binding affinities, and modes of action of currently available EGFR TKIs towards p.L747P mutation.Materials and MethodsClinical data of NSCLC patients harboring p.L747P mutation who had received different generations of EGFR TKIs were collected from medical records. Computational structure of p.L747P was constructed and in vitro cellular kinase inhibition assay and mice xenograft experiment were performed to predict and confirm the binding affinities and antitumor activities of diverse EGFR TKIs.ResultsA total of five metastatic NSCLC patients with p.L747P mutation were included in the final analysis. Patients treated with second-generation (2G) TKI afatinib achieved numerically longer progression-free survival (range 2.4-8.5 months) than that with first-generation (1G, range 1.4-5.5 months) or third-generation (3G, range 1.6-7.5 months) TKIs. None of the patients administered 1G or 3G TKIs achieved tumor response, but two-thirds of them treated with afatinib achieved partial response. Dynamics simulation predicted that 2G TKIs presented the best binding affinity to p.L747P mutation. The cellular kinase inhibition assay and mice xenograft experiment confirmed that afatinib could potently inhibit p.L747P-mutant cells and significantly reduce p.L747P-mutant tumor growth (P< 0.001), together with reduced phosphorylation of EGFR and its downstream signalings.ConclusionsThe uncommon p.L747P mutation in EGFR exon 19 resulted in a poor response to first-generation EGFR TKIs. Afatinib revealed a better clinical response and binding affinity compared with osimertinib for this specific alteration.

Abstract 1262: BLU-701 is a highly potent, brain-penetrant and WT-sparing next-generation EGFR TKI for the treatment of sensitizing (ex19del, L858R) and C797S resistance mutations in metastatic NSCLC

Abstract BACKGROUND: Non-small cell lung cancer (NSCLC) represents 80% of lung cancers, the second leading cause of cancer deaths globally. Mutations in the kinase domain of the epidermal growth factor receptor (EGFR) are genomic drivers in a molecular sub-type of NSCLC that is sensitive to tyrosine kinase inhibitors (TKIs). Third-generation, irreversible TKIs, such as osimertinib and lazertinib, have become standard of care and are now widely used as first-line therapy in EGFR-driven metastatic NSCLC. However, resistance invariably arises during treatment. The C797S mutation is the most frequent on-target resistance mechanism in response to third-generation TKIs when used in the first-line setting. There are currently no approved therapies for patients who progress with a C797S mutation. Although first-generation TKIs inhibit EGFR with a C797S mutation, they carry liabilities of 1) insufficient selectivity over wild-type (WT) EGFR, which precludes maximal target coverage and results in dose-limiting adverse events; and 2) limited brain penetration. METHODS: BLU-701 activity was tested in biochemical assays for EGFR mutants and EGFR WT. Cellular activity was evaluated by a phosphorylation specific EGFR AlphaLisa assay in WT cell lines or those expressing EGFR mutations. The in vivo antitumor activity of BLU-701 was assessed in a PC9 ex19del cell line-derived tumor xenograft (CDX) model. RESULTS: We have developed an orally available, single-digit nanomolar, brain-penetrant, WT-sparing, reversible EGFR inhibitor that is active against the C797S resistance mutation. BLU-701 is equally potent against both the sensitizing mutations ex19del and L858R, and the resistance double mutants ex19del/C797S and L858R/C797S. BLU-701 is brain penetrant (Kpu,u &amp;gt;0.9) and demonstrates a selectivity over WT EGFR that compares favorably with osimertinib. Oral administration of BLU-701 to PC9 ex19del tumor-bearing mice resulted in strong and prolonged pathway suppression and tumor regression at tolerated doses. CONCLUSION: Due to its potent pharmacological activity and selectivity for mutant EGFR, BLU-701 has the potential to demonstrate activity in first-line and resistance settings as a single agent and in combination therapy, addressing potential tumor heterogeneity. The pre-clinical data described here supports the clinical development of BLU-701 in EGFR-driven NSCLC. Citation Format: Chiara Conti, John Campbell, Rich Woessner, Jian Guo, Yoav Timsit, Maria Iliou, Scott Wardwell, Alison Davis, Sharon Chicklas, John Hsieh, Meredith Eno, Omar Ahmad, Dilinie Fernando, Kevin Barvian, Joseph Kim, Steven Kazmirski, Emanuele Perola, Tom Dineen, Victoria Brown, Timothy Guzi, Ayşegül Özen, Faith Stevison, Caitlin Utt, Clare Medendorp, Robert Meissner, Marion Dorsch, Klaus Hoeflich. BLU-701 is a highly potent, brain-penetrant and WT-sparing next-generation EGFR TKI for the treatment of sensitizing (ex19del, L858R) and C797S resistance mutations in metastatic NSCLC [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1262.

The use of COLD-PCR and pyrosequencing for sensitive detection of EGFR T790M mutation

A sensitive and convenient method for the detection of epidermal growth factor receptor (EGFR) T790M mutation in non-small cell lung cancer (NSCLC) patients with acquired resistance to tyrosine kinase inhibitors (TKIs) would be desirable to guide treatment strategy. Consequently, studies have focused on sensitive characterization of EGFR T790M mutation. Herein, two methods of co-amplification at lower denaturation temperature PCR (COLD-PCR) and pyrosequencing were combined (COLDPCR/ pyrosequencing) for detecting EGFR T790M mutation. Evaluation of mutation-containing dilutions revealed that the sensitivities of COLD-PCR/pyrosequencing and conventional PCR/pyrosequencing assays for the detection of the T790M mutation were 0.1 and 5%, respectively, indicating a 50-fold increase in sensitivity. When the T790M mutation in 20 clinical NSCLC samples who had relapsed under firstgeneration EGFR TKI were further determined using COLD-PCR/pyrosequencing and conventional PCR/pyrosequencing, the detection rates were 35% (7/20) and 25% (5/20), respectively. All patients who were positive for the T790M mutation with conventional PCR/pyrosequencing were also found to be positive with COLD-PCR/pyrosequencing. The discordant cases were 2 samples with no T790M mutation detected with conventional PCR/pyrosequencing, but which were positive with COLD-PCR/pyrosequencing. COLD-PCR/pyrosequencing is a sensitive and cost-effective tool for detecting the T790M mutation which will permit an improvement of therapeutic management.

Impact of concurrent genomic alterations in epidermal growth factor receptor (EGFR)-mutated lung cancer.

Comprehensive characterization of the genomic landscape of epidermal growth factor receptor (EGFR)-mutated lung cancers have identified patterns of secondary mutations beyond the primary oncogenic EGFR mutation. These include concurrent pathogenic alterations affecting p53 (60–65%), RTKs (5–10%), PIK3CA/KRAS (3–23%), Wnt (5–10%), and cell cycle (7–25%) pathways as well as transcription factors such as MYC and NKX2-1 (10–15%). The majority of these co-occurring alterations were detected or enriched in samples collected from patients at resistance to tyrosine kinase inhibitor (TKI) treatment, indicating a potential functional role in driving resistance to therapy. Of note, these co-occurring tumor genomic alterations are not necessarily mutually exclusive, and evidence suggests that multiple clonal and sub-clonal cancer cell populations can co-exist and contribute to EGFR TKI resistance. Computational tools aimed to classify, track and predict the evolution of cancer clonal populations during therapy are being investigated in pre-clinical models to guide the selection of combination therapy switching strategies that may delay the development of treatment resistance. Here we review the most frequently identified tumor genomic alterations that co-occur with mutated EGFR and the evidence that these alterations effect responsiveness to EGFR TKI treatment.

Start Selective and Rigidify: The Discovery Path toward a Next Generation of EGFR Tyrosine Kinase Inhibitors.

The epidermal growth factor receptor (EGFR), when carrying an activating mutation like del19 or L858R, acts as an oncogenic driver in a subset of lung tumors. While tumor responses to tyrosine kinase inhibitors (TKIs) are accompanied by marked tumor shrinkage, the response is usually not durable. Most patients relapse within two years of therapy often due to acquisition of an additional mutation in EGFR kinase domain that confers resistance to TKIs. Crucially, oncogenic EGFR harboring both resistance mutations, T790M and C797S, can no longer be inhibited by currently approved EGFR TKIs. Here, we describe the discovery of BI-4020, which is a noncovalent, wild-type EGFR sparing, macrocyclic TKI. BI-4020 potently inhibits the above-described EGFR variants and induces tumor regressions in a cross-resistant EGFRdel19 T790M C797S xenograft model. Key was the identification of a highly selective but moderately potent benzimidazole followed by complete rigidification of the molecule through macrocyclization.

Targeting FGFR overcomes EMT-mediated resistance in EGFR mutant non-small cell lung cancer.

Evolved resistance to tyrosine kinase inhibitor (TKI) targeted therapies remains a major clinical challenge. In EGFR mutant non-small cell lung cancer (NSCLC), failure of EGFR TKIs can result from both genetic and epigenetic mechanisms of acquired drug resistance. Widespread reports of histologic and gene expression changes consistent with an epithelial-to-mesenchymal transition (EMT) have been associated with initially surviving drug tolerant persister cells, which can seed bona fide genetic mechanisms of resistance to EGFR TKIs. While therapeutic approaches targeting fully resistant cells, such as those harboring an EGFRT790M mutation, have been developed, a clinical strategy for preventing the emergence of persister cells remains elusive. Using mesenchymal cell lines derived from biopsies of patients who progressed on EGFR TKI as surrogates for persister populations, we performed whole-genome CRISPR screening and identified FGFR1 as the top target promoting survival of mesenchymal EGFR mutant cancers. Although numerous previous reports of FGFR signaling contributing to EGFR TKI resistance in vitro exist, the data has not yet been sufficiently compelling to instigate a clinical trial testing this hypothesis, nor has the role of FGFR in promoting the survival of persister cells been elucidated. In this study, we find that combining EGFR and FGFR inhibitors inhibited the survival and expansion of EGFR mutant drug tolerant cells over long time periods, preventing the development of fully resistant cancers in multiple vitro models and in vivo. These results suggest that dual EGFR and FGFR blockade may be a promising clinical strategy for both preventing and overcoming EMT-associated acquired drug resistance and provide motivation for clinical study of combined EGFR and FGFR inhibition in EGFR-mutated NSCLCs.

Acquired Resistance of EGFR-Mutated Lung Cancer to Tyrosine Kinase Inhibitor Treatment Promotes PARP Inhibitor Sensitivity

SUMMARYLung cancers with oncogenic mutations in the epidermal growth factor receptor (EGFR) invariably acquire resistance to tyrosine kinase inhibitor (TKI) treatment. Vulnerabilities of EGFR TKI-resistant cancer cells that could be therapeutically exploited are incompletely understood. Here, we describe a poly (ADP-ribose) polymerase 1 (PARP-1) inhibitor-sensitive phenotype that is conferred by TKI treatment in vitro and in vivo and appears independent of any particular TKI resistance mechanism. We find that PARP-1 protects cells against cytotoxic reactive oxygen species (ROS) produced by nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX). Compared to TKI-naive cells, TKI-resistant cells exhibit signs of increased RAC1 activity. PARP-1 catalytic function is required for PARylation of RAC1 at evolutionarily conserved sites in TKI-resistant cells, which restricts NOX-mediated ROS production. Our data identify a role of PARP-1 in controlling ROS levels upon EGFR TKI treatment, with potentially broad implications for therapeutic targeting of the mechanisms that govern the survival of oncogene-driven cancer cells.

EGFR plasma mutation in prediction models for resistance with EGFR TKI and survival of non-small cell lung cancer

BackgroundThis study aims to clarify the prognostic role of epidermal growth factor receptor (EGFR) mutations in plasma of non-small cell lung cancer (NSCLC) for resistance to tyrosine kinase inhibitor (TKI), in correlation with clinical characteristics. A total of 94 Adenocarcinoma, clinical stage IV NSCLC patients with either E19del or L858R mutation were admitted to the prospective study from Jan-2016 to Jul-2018. EGFR mutations in plasma were detected by scorpions ARMS method. The Kaplan–Meier and Cox regression methods were used to estimate and test the difference of progression-free survival (PFS) and overall survival (OS) between groups. The prognostic power of each factor was appraised by the Bayesian Model Averaging (BMA) method.ResultsAmong 94 patients, 28 cases still are good responses according to the RECIST criteria and negative for EGFR mutations in plasma. Of 66 resistant patients, EGFR mutations were positive in plasma of 57 cases (86.4%) which was higher than the value of pre-treatment (48.5%). Of which, 17 patients (25.8%) have the occurrence of EGFR mutations in plasma earlier than progression 2.1 (0.6–7.9) months. The secondary T790M mutation was found in the plasma of 32 cases (48.5%). Median PFS and OS for the study subjects were 12.9 (11.0–14.2) and 29.5 (25.2–41.3) months, respectively. The post-treatment EGFR plasma test with brain and new metastasis were detected as independent prognostic factors for worse PFS (P = 0.008, 0.016 and 0.028, respectively). While EGFR plasma (P = 0.044) with bone metastasis at baseline (P = 0.012), new metastasis (P = 0.003), and high cfDNA concentration (P = 0.004) serve as the worse survival factors, surgery treatment helps to prolong OS in NSCLC treated with EGFR TKI (P = 0.012). BMA analysis identified EGFR plasma test as the strongest prognostic factor for both PFS and OS (possibility of 100% and 99.7%, respectively).ConclusionsEGFR plasma test is the powerfully prognostic factor for early resistance with EGFR TKI and worse survival in NSCLC regardless of clinical characteristics.

Activity of EGFR TKIs in Caucasian Patients With NSCLC Harboring Potentially Sensitive Uncommon EGFR Mutations

BackgroundMolecular characterization of non–small-cell lung cancer (NSCLC), defined predictive and druggable mutations that greatly modified patient prognoses. The most frequent driver mutations detected in NSCLC are epidermal growth factor receptor (EGFR) mutations, accounting for approximately 90% of exon 19 deletions and exon 21 point mutations. The other EGFR mutations are classified as uncommon or nonclassical and include exon 18 point mutations, exon 20 insertions, and combined mutations, which present different sensitivity to tyrosine kinase inhibitor (TKI) targeting. Patients and MethodsWe collected data from EGFR TKI-naive patients with metastatic NSCLC, harboring EGFR exon 18 mutations and EGFR combined mutations treated with first- or second-generation EGFR TKIs. Efficacy end points were evaluated considering the activity of EGFR TKIs in exon 18 versus double-mutation EGFR groups. ResultsEighty-eight patients harboring uncommon EGFR mutations were evaluated in our analysis, and subdivided into 2 group: complex mutations (cohort A = 46 patients) and double mutations in exon 18 (cohort B = 42 patients). The results showed a median progression-free survival of 8.3 versus 12.3 months (hazard ratio [HR], 0.65; P = .06) and a median overall survival of 17.0 versus 31.0 months (HR, 0.62, P = .04) favoring the EGFR combination group. Within the combination group, no detrimental effect was associated with exon 20 mutations. ConclusionOur study confirmed that EGFR exon 18 and combination mutations might be considered potentially sensitive uncommon mutations, with a similar survival compared with the well known common EGFR mutations. Comparative analysis showed that patients with complex mutations achieved longer survival compared with the exon 18 group, without correlation with the presence of exon 20 mutations.

140PD Complex epidermal growth factor receptor (EGFR) mutations and responses to tyrosine kinase inhibitors (TKIs) in advanced lung adenocarcinomas

Background: Two or more different epidermal growth factor receptor (EGFR) mutations can be detected within a single tumor sample, which represents complex mutations. However, the frequency and efficacy of tyrosine kinase inhibitor (TKI) treatments for patients harboring these mutations are unknown. Methods: From January 2011 to January 2017, patients diagnosed with EGFR mutation were screened. The effectiveness of TKIs in patients with complex mutations was retrospectively analyzed. Results: A total of 16,840 subjects were screened, with 5898 positive patients. 187 patients (3.2% of all EGFR mutant patients) had complex EGFR mutations with 95 of advanced lung adenocarcinoma patients were treated with TKIs. The objective response rate (ORR) for patients who had Del-19 + 21L858R (Group A, n = 27), Del-19/21L858R + atypical mutations (Group B, n = 28), double atypical mutations (Group C, n = 20) and complex mutations with primary drug-resistant pattern (Group D, n = 20) were 72.7%, 54.2%, 66.7% and 15.0%, respectively. Median progression free survival (PFS) in the four groups were 18.2 months (95% CI, 12.0 months to 24.4 months), 10.1 months (95% CI, 6.5 months to 13.7 months), 11.1 months (95% CI, 6.8 months to 15.4 months) and 1.4 months (95% CI, 0.2 months to 2.5 months), respectively. Conclusions: These results suggest on the largest sample size that EGFR–TKI therapy is effective in patients with Del-19 + 21L858R, Del-19/21L858R + atypical mutations and double atypical mutations, but less effective in patients with primary drug–resistant pattern. Patients with the Del-19 + 21L858R mutations may therefore benefit more from treatment with first–generation TKIs. Legal entity responsible for the study: Bo Zhang Funding: Has not received any funding Disclosure: All authors have declared no conflicts of interest.

Response to tyrosine kinase inhibitors (TKIs) in non-small cell lung cancer (NSCLC) patients with de novo epidermal growth factor receptor (EGFR) T790M and S768I resistance mutations.

e20557 Background: Patients with synchronous de novo EGFR sensitising and resistance mutations are rare. Little is known about the response of these patients to EGFR TKIs, especially in a Caucasian population. Methods: We identified NSCLC patients found to have EGFR mutations using PCR-based fragment length analysis, mass spectrometry-based genotyping (Sequenom), and Sanger sequencing using a large multi-institutional database. Baseline clinical characteristics, response rate, progression free survival (PFS) and overall survival (OS) were calculated. Results: From 2008-2015, we observed de novo synchronous EGFR sensitising and resistance mutations in 12 patients representing an overall incidence of 3.6% of EGFR mutants and 0.4% of all NSCLC patients tested. Seven patients were treated using EGFR TKI therapy with erlotinib. In all cases, T790M (n = 4,50%) or S768I (n = 4, 50%) occurred concurrently with another sensitising EGFR mutation, either L858R (n = 4, 34%) or exon 19 deletion (n = 8, 66%). Objective responses were seen in two patients (29%). Three further patients had stable disease lasting 6, 23 and 54 months respectively. The median progression-free survival was 24 months and the median overall survival was 34 months. All patients with baseline EGFR S768I mutations (n = 3) had an objective response or stable disease on erlotinib while two of four patients with T790M demonstrated de novo resistance. Conclusions: This is the largest Irish review of synchronous de novo EGFR mutations. The incidence of co-occurring EGFR mutations was 0.4% and erlotinib demonstrated activity in this cohort of patients. Ongoing trials will determine whether next-generation EGFR TKIs such as osimertinib are preferable as first-line therapy in these patients.

Quantitative Tyrosine Phosphoproteomics of Epidermal Growth Factor Receptor (EGFR) Tyrosine Kinase Inhibitor-treated Lung Adenocarcinoma Cells Reveals Potential Novel Biomarkers of Therapeutic Response

Mutations in the Epidermal growth factor receptor (EGFR) kinase domain, such as the L858R missense mutation and deletions spanning the conserved sequence 747LREA750, are sensitive to tyrosine kinase inhibitors (TKIs). The gatekeeper site residue mutation, T790M accounts for around 60% of acquired resistance to EGFR TKIs. The first generation EGFR TKIs, erlotinib and gefitinib, and the second generation inhibitor, afatinib are FDA approved for initial treatment of EGFR mutated lung adenocarcinoma. The predominant biomarker of EGFR TKI responsiveness is the presence of EGFR TKI-sensitizing mutations. However, 30-40% of patients with EGFR mutations exhibit primary resistance to these TKIs, underscoring the unmet need of identifying additional biomarkers of treatment response. Here, we sought to characterize the dynamics of tyrosine phosphorylation upon EGFR TKI treatment of mutant EGFR-driven human lung adenocarcinoma cell lines with varying sensitivity to EGFR TKIs, erlotinib and afatinib. We employed stable isotope labeling with amino acids in cell culture (SILAC)-based quantitative mass spectrometry to identify and quantify tyrosine phosphorylated peptides. The proportion of tyrosine phosphorylated sites that had reduced phosphorylation upon erlotinib or afatinib treatment correlated with the degree of TKI-sensitivity. Afatinib, an irreversible EGFR TKI, more effectively inhibited tyrosine phosphorylation of a majority of the substrates. The phosphosites with phosphorylation SILAC ratios that correlated with the TKI-sensitivity of the cell lines include sites on kinases, such as EGFR-Y1197 and MAPK7-Y221, and adaptor proteins, such as SHC1-Y349/350, ERRFI1-Y394, GAB1-Y689, STAT5A-Y694, DLG3-Y705, and DAPP1-Y139, suggesting these are potential biomarkers of TKI sensitivity. DAPP1, is a novel target of mutant EGFR signaling and Y-139 is the major site of DAPP1 tyrosine phosphorylation. We also uncovered several off-target effects of these TKIs, such as MST1R-Y1238/Y1239 and MET-Y1252/1253. This study provides unique insight into the TKI-mediated modulation of mutant EGFR signaling, which can be applied to the development of biomarkers of EGFR TKI response.

Clinical outcomes of advanced non-small-cell lung cancer patients with EGFR mutation, ALK rearrangement and EGFR/ALK co-alterations.

The co-occurrence of epidermal growth factor receptor (EGFR) mutations and anaplastic lymphoma kinase (ALK) rearrangements constitutes a rare molecular subtype of non-small-cell lung cancer (NSCLC). Herein, we assessed the clinical outcomes and incidence of acquired resistance to tyrosine kinase inhibitors (TKIs) in this subtype. So we enrolled 118 advanced NSCLC treated with TKIs. EGFR mutations and ALK rearrangements were detected by DNA sequencing or Scorpion amplification refractory mutation system and fluorescence in situ hybridization respectively. Immunohistochemistry was used to evaluate the activation of associated proteins. We found that nine in ten patients with EGFR/ALK co-alterations had good response with first-line EGFR TKI, and the objective response rate (ORR) of EGFR TKIs was 80% (8/10) for EGFR/ALK co-altered and 65.5% (55/84) for EGFR-mutant (P = 0.57), with a median progression-free survival (PFS) of 11.2 and 13.2 months, (hazard ratio [HR]=0.95, 95% [CI], 0.49-1.84, P= 0.87). ORR of crizotinib was 40% (2/5) for EGFR/ALK co-altered and 73.9% (17/23) for ALK-rearranged (P= 0.29), with a median PFS of 1.9 and 6.9 months (hazard ratio [HR], 0.40; 95% [CI] 0.15-1.10, P = 0.08). The median overall survival (OS) was 21.3, 23.7, and 18.5 months in EGFR-mutant, ALK-rearranged, and EGFR/ALK co-altered (P= 0.06), and there existed a statistically significant difference in OS between ALK-rearranged and EGFR/ALK co-altered (P=0.03). Taken together, the first-line EGFR-TKI might be the reasonable care for advanced NSCLC harbouring EGFR/ALK co-alterations, whether or nor to use sequential crizotinib should be guided by the status of ALK rearrangement and the relative level of phospho-EGFR and phospho-ALK.

WITHDRAWN:Clinical efficacy of erlotinib, a salvage treatment for non-small cell lung cancer patients following gefitinib failure.

Ahead of Print article withdrawn by publisher.

Frequency of epidermal growth factor receptor mutations in Jordanian lung adenocarcinoma patients at diagnosis.

Somatic mutations of the epidermal growth factor receptor (EGFR) gene have been associated with tumor response to tyrosine kinase inhibitors (TKIs) and favorable outcome in patients with non-small-cell lung cancer (NSCLC). The activating mutations that confer sensitivity to EGFR TKIs are present in the TK domain of the EGFR gene. This study aims to report on the prevalence of EGFR mutations in NSCLC and non-squamous lung cancer patients at diagnosis, using genomic deoxyribonucleic acid (DNA) obtained from paraffin-embedded tissue samples. We collected formalin.fixed, paraffin.embedded. (FFPE) tissue samples from 166. cases of lungadenocarcinomas referring to Jordan University Hospital and King Hussein Cancer Center between 2007 and first half of 2013. None of the patients met the definition of never smoker defined as those who smoked less than 100 cigarettes in their lifetime. We evaluated EGFR mutations by nested polymerase chain reaction. (PCR) followed by direct sequencing of the EGFR kinase domain from exon 18 to 21. Six different point mutations were detected in 24 patients (14.46%) of the study population. The resultant mutations were as follows: Ten patients have deletion in exon 19, sevenpatients have L858R, two patients have L861P, and one of each of the following: A735T, D770_N771 insY, L858P, L861Q, and G917C. The present study revealed that the EGFR mutations rate in Jordanian patients with adenocarcinoma of the lung was higher than in African-American, and some white Caucasian patients, and was lower than in patients in East Asia, and other countries of South Asia.

Clinical efficacy of erlotinib, a salvage treatment for non-small cell lung cancer patients following gefitinib failure.

Background/Aims:The purpose of this study was to identify predictive factors for erlotinib treatment in non-small cell lung cancer (NSCLC) patients following gefitinib failure.Methods:Forty-five patients with NSCLC who were treated with erlotinib following gefitinib failure at Seoul National University Hospital between August 2005 and November 2011 were enrolled. Epidermal growth factor receptor (EGFR) mutation status, pathologic findings and other clinical factors, including response to tyrosine kinase inhibitors (TKIs) and progression-free survival (PFS), were evaluated.Results:Of the 45 patients, 40 patients (88.8%) had adenocarcinoma. The following EGFR mutations were observed: five patients with a deletion of exon 19, six patients with an L858R mutation, three patients with wild-type EGFR, and 31 patients with unknown mutations. The response rate of erlotinib was 4.4%, and stable disease was 42.2%. The median PFS for erlotinib was 2.6 months (95% confidence interval, 1.4 to 3.7). Patients with a PFS ≥ 4 months during previous gefitinib treatment had a significantly longer PFS with erlotinib (3.3 months vs. 1.6 months, respectively; p < 0.01) than patients with PFS < 4 months with gefitinib. According to multivariate analyses, PFS ≥ 4 months for previous gefitinib treatment was significantly associated with prolonged PFS with erlotinib (p = 0.04). However, the response rate of gefitinib and treatment sequence were not associated with prolonged PFS with erlotinib (p = 0.28 and p = 0.67, respectively).Conclusions:Following rechallenge with the EGFR TKI erlotinib following gefitinib failure, patients who showed prolonged PFS with gefitinib benefit from erlotinib. However, further prospective studies are needed to confirm these findings.

A cautionary lesson on the use of targeted methods for EGFR mutation analysis: a case report

Epidermal growth factor receptor (EGFR) mutation analysis is recommended for lung cancer patients prior to the prescription of first-line EGFR tyrosine kinase inhibitors in order to predict response to treatment....

A novel serum protein signature associated with resistance to epidermal growth factor receptor tyrosine kinase inhibitors in head and neck squamous cell carcinoma

BackgroundAcquired resistance to tyrosine kinase inhibitors (TKIs) is becoming a major challenge in the treatment of many cancers. Epidermal growth factor receptor (EGFR) is overexpressed in squamous carcinomas, notably those of the head and neck (HNSCC), and can be targeted with several TKIs. We aimed to identify soluble proteins suitable for development as markers of EGFR TKI resistance in cancer patients to aid in early and minimally invasive assessment of therapeutic responses. MethodsResistant HNSCC cell lines were generated by exposure to an EGFR TKI, gefitinib, in vitro. Cell lines were characterised for their biological behaviour in vitro (using growth inhibition assays, flow cytometry, western blots, antibody arrays and/or immunoassays) and in vivo (using subcutaneous tumour xenografts). Sera from EGFR-treated and -untreated HNSCC patients were analysed by immunoassay. ResultsTwo independent sublines of CAL 27 and a PJ34 subline with acquired resistance to EGFR TKIs (gefitinib, erlotinib and afatinib) were developed. Resistant cells grew as highly aggressive xenografts leading to reduced host survival rates compared with EGFR-TKI sensitive cells. This suggested a link between resistance in vitro and poor prognosis in vivo. A significant upregulation of proteins linked to tumour angiogenesis and invasion was identified in resistant cells. This ‘resistance-associated protein signature’ (RAPS) was detected in the sera of a small cohort of HNSCC patients and was associated with reduced survival. ConclusionWe have identified a protein signature associated with EGFR-TKI resistance that may also be linked to poor prognosis and warrants further investigation as a potential clinical biomarker.

EGFR Mutation Heterogeneity and the Mixed Response to EGFR Tyrosine Kinase Inhibitors of Lung Adenocarcinomas

Non-small cell lung cancer patients with epidermal growth factor receptor (EGFR) mutations have mixed responses to tyrosine kinase inhibitors (TKIs). Intertumor heterogeneity in EGFR mutations is one potential explanation for this phenomenon. We performed direct sequencing to identify EGFR mutations in 180 pairs of lung adenocarcinoma samples (from 3,071 patients). The high-resolution melting method was used in discordant cases to confirm EGFR mutation status. Matching samples were divided into four groups: primary lesions detected at different times, primary tumors with matched metastatic lymph nodes, multiple pulmonary nodules, and primary tumors with matched distant metastases. Multivariate analyses were performed to evaluate correlations between heterogeneity and patient characteristics. In the study population, the discordance rate was 13.9% (25 of 180). The multiple pulmonary nodules group had the highest discordance rate of 24.4% (10 of 41; odds ratio for heterogeneity in primary lesions detected at different times, 6.37; 95% confidence interval, 1.71-23.72; p = .006). Discordance rates in the metachronous and synchronous settings were 15.7% (22 of 140) and 7.5% (three of 40), respectively. In the 34 patients who developed EGFR TKI resistance, 10 (29.4%) cases exhibited heterogeneity and five (14.7%) patients exhibited a mixed response to the drug. Three (8.8%) of the patients with a mixed response also exhibited discordant EGFR mutations. The overall discordance rate of EGFR mutation heterogeneity in Asian patients with pulmonary adenocarcinoma is relatively low, but the rate in patients with multiple pulmonary nodules is significantly higher. This observation may explain the mixed tumor response to EGFR TKIs.