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Background: Patients with non-small cell lung cancer (NSCLC) harboring activating EGFR mutations are sensitive to epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) but inevitably develop resistance to the inhibitors mostly through acquisition of the secondary T790M mutation. Although third-generation EGFR-TKIs overcome this resistance by selectively inhibiting EGFR with EGFR-TKI-sensitizing and T790M mutations, acquired resistance to third-generation EGFR-TKIs invariably develops., Methods: Next-generation sequencing (NGS) and fluorescence in situ hybridization (FISH) analysis were performed in an EGFR T790M-mutated NSCLC patient who had progressed after a third-generation EGFR-TKI, TAS-121. EGFR-mutated cell lines were subjected to a cell proliferation assay and western blotting analysis with EGFR-TKIs and a heat shock protein 90 (HSP90) inhibitor., Results: NGS and FISH analysis revealed EGFR amplification in the resistant cancer cells. While EGFR L858R/T90M-mutated cell line was sensitive to osimertinib or TAS-121 in vitro, EGFR-overexpressing cell lines displayed resistance to these EGFR-TKIs. Western blot analysis showed that EGFR phosphorylation and overexpression of EGFR in cell lines was not suppressed by third-generation EGFR-TKIs. In contrast, an HSP90 inhibitor reduced total and phosphorylated EGFR and inhibited the proliferation of resistant cell lines., Conclusions: EGFR amplification confers resistance to third-generation EGFR-TKIs which can be overcome by HSP90 inhibition. The results provide a preclinical rationale for the use of HSP90 inhibitors to overcome EGFR amplification-mediated resistance., (© 2021 The Authors. Thoracic Cancer published by China Lung Oncology Group and John Wiley & Sons Australia, Ltd.)

Objectives: Rapid tumor progression occurring after the discontinuation of epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) therapy is referred to as a disease flare of non-small cell lung cancer (NSCLC). The clinicopathological features of disease flares after osimertinib discontinuation remain unclear., Results: We report a patient with EGFR-mutated NSCLC who experienced the progression of leptomeningeal metastases as a disease flare shortly after the discontinuation of osimertinib despite the absence of radiological or cytological findings., Conclusion: If CNS symptoms develop immediately after the discontinuation of osimertinib, the possibility of a CNS disease flare should be considered even if no radiological or cytological findings are present., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Background: The FLAURA study was a multicenter, double-blind, Phase 3 study in which patients with previously untreated epidermal growth factor receptor mutation-positive advanced non-small-cell lung carcinoma were randomized 1:1 to oral osimertinib 80 mg once daily or standard-of-care (gefitinib 250 mg or erlotinib 150 mg, once daily) to compare safety and efficacy. In the overall FLAURA study, significantly better progression-free survival was shown with osimertinib versus standard-of-care., Methods: Selected endpoints, including progression-free survival (primary endpoint), overall survival, objective response rate, duration of response and safety were evaluated for the Japanese subset of the FLAURA study., Results: In Japan, 120 eligible Japanese patients were randomized to osimertinib (65 patients) or gefitinib (55 patients) treatment from December 2014 to June 2017. Median progression-free survival was 19.1 (95% confidence interval, 12.6, 23.5) and 13.8 (95% confidence interval, 8.3, 16.6) months with osimertinib and gefitinib, respectively (hazard ratio, 0.61; 95% confidence interval, 0.38, 0.99). Median overall survival was not reached in either treatment arm (data were immature). In the osimertinib and gefitinib arms, objective response rate was 75.4% (49/65) and 76.4% (42/55), and median duration of response from onset was 18.4 (95% confidence interval, not calculated) and 9.5 (95% confidence interval, 6.2, 13.9) months, respectively. The incidence of adverse events was similar in the two groups. The frequency of Grade ≥3 interstitial lung disease and pneumonitis in the two groups were the same (one patient)., Conclusions: As the first-line therapy, osimertinib showed significantly improved efficacy versus gefitinib in the Japanese population of the FLAURA study. No new safety concerns were raised., Clinical Trial Registration: NCT02296125 (ClinicalTrials.gov).

Background: Osimertinib is an oral, third-generation, irreversible epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) that selectively inhibits both EGFR-TKI-sensitizing and EGFR T790M resistance mutations. We compared osimertinib with standard EGFR-TKIs in patients with previously untreated, EGFR mutation-positive advanced non-small-cell lung cancer (NSCLC)., Methods: In this double-blind, phase 3 trial, we randomly assigned 556 patients with previously untreated, EGFR mutation-positive (exon 19 deletion or L858R) advanced NSCLC in a 1:1 ratio to receive either osimertinib (at a dose of 80 mg once daily) or a standard EGFR-TKI (gefitinib at a dose of 250 mg once daily or erlotinib at a dose of 150 mg once daily). The primary end point was investigator-assessed progression-free survival., Results: The median progression-free survival was significantly longer with osimertinib than with standard EGFR-TKIs (18.9 months vs. 10.2 months; hazard ratio for disease progression or death, 0.46; 95% confidence interval [CI], 0.37 to 0.57; P<0.001). The objective response rate was similar in the two groups: 80% with osimertinib and 76% with standard EGFR-TKIs (odds ratio, 1.27; 95% CI, 0.85 to 1.90; P=0.24). The median duration of response was 17.2 months (95% CI, 13.8 to 22.0) with osimertinib versus 8.5 months (95% CI, 7.3 to 9.8) with standard EGFR-TKIs. Data on overall survival were immature at the interim analysis (25% maturity). The survival rate at 18 months was 83% (95% CI, 78 to 87) with osimertinib and 71% (95% CI, 65 to 76) with standard EGFR-TKIs (hazard ratio for death, 0.63; 95% CI, 0.45 to 0.88; P=0.007 [nonsignificant in the interim analysis]). Adverse events of grade 3 or higher were less frequent with osimertinib than with standard EGFR-TKIs (34% vs. 45%)., Conclusions: Osimertinib showed efficacy superior to that of standard EGFR-TKIs in the first-line treatment of EGFR mutation-positive advanced NSCLC, with a similar safety profile and lower rates of serious adverse events. (Funded by AstraZeneca; FLAURA ClinicalTrials.gov number, NCT02296125 .).

Objective: The Phase III, randomized, open-label IPASS study (NCT00322452) of first-line epidermal growth factor receptor tyrosine kinase inhibitor (EGFR TKI) gefitinib versus carboplatin/paclitaxel for Asian patients with advanced non-small-cell lung cancer (NSCLC) showed that investigator-assessed progression-free survival (PFS) and objective response rate (ORR) were significantly prolonged in patients with EGFR mutation-positive NSCLC who received gefitinib versus patients with EGFR mutation-negative NSCLC. We report post-hoc analyses of IPASS data by blind independent central review (BICR), performed at the request of the US FDA, in a subset of patients with EGFR mutation-positive NSCLC., Patients and Methods: Eligible patients (aged ≥18 years; histologically/cytologically confirmed Stage IIB/IV adenocarcinoma NSCLC; non- or former light-smokers; treatment-naïve) were randomly assigned 1:1 to gefitinib (250mg/day) or carboplatin (dose calculated to produce an area under the curve of 5 or 6 mg/mL/minute)/paclitaxel (200mg/m 2 ). Primary endpoint: PFS. BICR analyses included PFS, ORR, and duration of response (DoR)., Results: Scans from 186 IPASS patients (gefitinib n=88, carboplatin/paclitaxel n=98) with EGFR mutation-positive NSCLC were available for BICR. Consistent with investigator-assessed results, in patients with EGFR mutation-positive NSCLC: PFS (hazard ratio 0.54; 95% confidence interval [CI] 0.38, 0.79; p=0.0012) and ORR (odds ratio 3.00; 95% CI 1.63, 5.54; p=0.0004) were significantly longer with gefitinib versus carboplatin/paclitaxel. The median DoR by BICR was 9.6 months with gefitinib and 5.5 months with carboplatin/paclitaxel., Conclusion: BICR analysis of IPASS data support the original, investigator-assessed results. EGFR mutation-positive status remains a significant predictor of response to first-line TKI therapy., (Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.)

Background: Gastric acid-suppressing medications (AS), namely, proton pump inhibitors and histamine-2 receptor antagonists, increase gastric pH, which may reduce the absorption of the epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors-erlotinib and gefitinib., Patients and Methods: From 2008 to 2011, 130 consecutive patients with advanced non-small-cell lung cancer (NSCLC) harboring EGFR mutations were treated with either erlotinib or gefitinib at our institution. The clinical characteristics of the patients were reviewed, and the efficacy and toxicity of erlotinib and gefitinib were compared for patients receiving and not receiving AS., Results: Among the 130 patients, 47 received AS (AS users group), while the remaining 83 patients did not (AS non-users group). The overall response rate (ORR) and median progression-free survival (PFS) in the subject population was 60% and 10 months, respectively. In the AS users and non-users groups, the ORR was 64% and 63% (P = .92), while the median PFS was 8.7 and 10.7 months (P = .13), respectively. No significant difference in either ORR or PFS was observed between the 2 groups. With regard to the toxicity, the frequencies of rash (83% vs. 86%; P = .60) and diarrhea (34% vs. 29%; P = .55) were similar for both groups. A multivariate analysis identified that AS use was not a significant factor for either PFS or OS., Conclusion: Concurrent use of AS did not affect the efficacy or toxicity of erlotinib and gefitinib in patients with advanced NSCLC harboring EGFR mutations., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Lung adenocarcinoma driven by somatic EGFR mutations is more prevalent in East Asians (30-50%) than in European/Americans (10-20%). Here we investigate genetic factors underlying the risk of this disease by conducting a genome-wide association study, followed by two validation studies, in 3,173 Japanese patients with EGFR mutation-positive lung adenocarcinoma and 15,158 controls. Four loci, 5p15.33 (TERT), 6p21.3 (BTNL2), 3q28 (TP63) and 17q24.2 (BPTF), previously shown to be strongly associated with overall lung adenocarcinoma risk in East Asians, were re-discovered as loci associated with a higher susceptibility to EGFR mutation-positive lung adenocarcinoma. In addition, two additional loci, HLA class II at 6p21.32 (rs2179920; P =5.1 × 10(-17), per-allele OR=1.36) and 6p21.1 (FOXP4) (rs2495239; P=3.9 × 10(-9), per-allele OR=1.19) were newly identified as loci associated with EGFR mutation-positive lung adenocarcinoma. This study indicates that multiple genetic factors underlie the risk of lung adenocarcinomas with EGFR mutations.

Purpose: The objective of this study was to evaluate the utility of analyzing cell-free plasma DNA (cfDNA) by picoliter-droplet digital polymerase chain reaction (ddPCR) to detect EGFR mutations that confer resistance to tyrosine-kinase inhibitors (TKIs) used for treatment of lung adenocarcinoma (LADC)., Experimental Design: Thirty-five LADC patients who received epidermal growth factor receptor (EGFR)-TKI therapy, including ten who received tumor rebiopsy after development of resistance, were subjected to picoliter-ddPCR-cfDNA analysis to determine the fraction of cfDNA with TKI-sensitive (L858R and inflame exon 19 deletions) and -resistant (i.e., T790M) mutations, as well as their concordance with mutation status in rebiopsied tumor tissues., Results: cfDNA samples from 15 (94%) of 16 patients who acquired resistance were positive for TKI-sensitive mutations. Also, 7 (44%) were positive for the T790M mutation, with fractions of T790M (+) cfDNA ranging from 7.4% to 97%. T790M positivity in cfDNA was consistent in eight of ten patients for whom rebiopsied tumor tissues were analyzed, whereas the remaining cases were negative in cfDNA and positive in rebiopsied tumors. Prior to EGFR-TKI therapy, cfDNAs from 9 (38%) and 0 of 24 patients were positive for TKI-sensitive and T790M mutations, respectively. Next-generation sequencing of cfDNA from one patient who exhibited innate resistance to TKI despite a high fraction of TKI-sensitive mutations and the absence of the T790M mutation in his cfDNA revealed the presence of the L747P mutation, a known driver of TKI resistance., Conclusion: Picoliter-ddPCR examination of cfDNA, supported by next-generation sequencing analysis, enables noninvasive assessment of EGFR mutations that confer resistance to TKIs., Implications for Practice: Noninvasive monitoring of the predominance of tumors harboring the secondary T790M mutation in the activating mutation in EGFR gene is necessary for precise and effective treatment of lung adenocarcinoma. Because cells harboring the T790M mutation are resistant to epidermal growth factor receptor-tyrosine-kinase inhibitors (TKIs), the predominance of tumor cells harboring the T790M mutations influences the choice of whether to use conventional or next-generation TKIs. Digital polymerase chain reaction-based examination of cfDNA is a promising method; however, its feasibility, including its consistency with examination of rebiopsied tumor tissue, has not been fully proven. Here, picoliter-droplet digital polymerase chain reaction technology is presented as a candidate method for testing cfDNA and assessing the predominance of T790M-mutant tumors., (©AlphaMed Press.)

Background: Progression patterns at the response evaluation criteria in solid tumors-progressive disease (RECIST-PD) during treatment with epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) for advanced non-small cell lung cancer (NSCLC) in patients harboring an EGFR mutation are clinically heterogeneous. We evaluated the association between progression patterns during EGFR-TKI treatment and prognosis after treatment in such patients., Methods: From 2008 to 2012, 160 consecutive patients with advanced NSCLC harboring an EGFR mutation were treated with EGFR-TKIs (erlotinib or gefitinib). Among these, 104 who experienced RECIST-PD were retrospectively evaluated for initial response to EGFR-TKIs, progression sites, focus of progression (solitary lesion or multiple lesions), symptom status at RECIST-PD evaluation, and post-progression survival (PPS)., Results: Of 104 patients, 96 (92%) had an EGFR major mutation, and 50 (48%) received EGFR-TKIs as first-line treatment. Overall response rate and median time to RECIST-PD on EGFR-TKIs were 68% and 8.2 months, respectively. At the time of attaining RECIST-PD status, 44 (42%) patients were symptomatic, and 60 (58%) were asymptomatic. Progression sites at RECIST-PD were isolated brain in 17 (16%) patients and systemic in 87 (84%): 24 (23%) had a solitary lesion, and 80 (77%) had multiple lesions. After RECIST-PD assessment, 40 (38%) patients continued EGFR-TKIs, and 25 (24%) switched to cytotoxic agents; 10 (10%) received local radiotherapy for an isolated progression site (brain 6; bone 3; lung 1). Median PPS was 10.8 months. Multivariate analysis revealed that asymptomatic or solitary lesion status was associated with significantly longer PPS (asymptomatic: HR 0.36, 95% CI 0.21-0.62, P<0.01; solitary progression lesion: HR 0.45, 95% CI 0.18-99, P=0.04)., Conclusions: Progression patterns at the RECIST-PD during EGFR-TKI treatment of advanced NSCLC in patients harboring an EGFR mutation are widely diverse, and might be associated with clinical outcome after treatment failure., (Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.)

Background: Many patients are forced to discontinue treatment with EGFR tyrosine kinase inhibitors (TKIs), particularly gefitinib, due to severe hepatotoxicity. Here, we investigated the association between the rate of severe hepatotoxicity and single nucleotide polymorphisms (SNPs) in metabolic enzymes., Materials and Methods: Multi-SNP analyses were performed in 60 patients with EGFR-mutated non-small cell lung cancer using blood samples obtained prior to starting treatment with gefitinib. The poor metabolizer (PM) phenotype was defined as homozygosity or double heterozygosity for variant alleles that confer reduced enzyme activities. Associated enzymes were screened using univariate logistic regression analyses adjusted for multiplicity and were further evaluated using multivariate logistic regression analyses to determine the influence of these enzymes on severe hepatotoxicity., Results: Severe hepatotoxicity was detected in 19 (32%) of the 60 patients. Patient phenotypes consisted of CYP3A5, PM/non-PM (31/29) and CYP2D6, PM/non-PM (5/55). In multivariate logistic regression analyses, the rate of severe hepatotoxicity was significantly higher among patients with PM phenotypes than those without (CYP3A5 PM vs. non-PM: 48.4% vs. 13.8%, P=0.0069; CYP2D6 PM vs. non-PM: 80.0% vs. 27.3%, P=0.0364). Of the 9 patients switched from gefitinib to erlotinib due to severe hepatotoxicity, 8 had a PM phenotype for CYP2D6 or CYP3A5. All cases were successfully managed without exacerbation of severe hepatotoxicity., Conclusions: Evaluation of SNPs in CYP3A5 and CYP2D6 can effectively predict severe hepatotoxicity induced by gefitinib. Erlotinib can be used as an alternative treatment for patients who develop gefitinib-induced severe hepatotoxicity., (Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.)

Objectives: In the first-line treatment of non-small cell lung cancer (NSCLC) harboring EGFR mutations, epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKIs) has been shown to yield a longer progression-free survival (PFS) rate than platinum-doublet chemotherapy; however, after the initial response, most patients develop resistance to the EGFR-TKIs. We hypothesized that the insertion of platinum-doublet chemotherapy after the initial response to EGFR-TKIs might prevent the emergence of acquired resistance to EGFR-TKIs and prolong survival., Methods: We carried out a phase II study of the following first-line treatment for patients with advanced NSCLC harboring EGFR mutations. Gefitinib (250 mg) was administered on days 1-56. Then, after a two-week drug-free period, three cycles of cisplatin (80 mg/m2) and docetaxel (60 mg/m2) were administered on days 71, 92, and 113. Thereafter, gefitinib was re-started on day 134 and continued until disease progression. The primary endpoint was the two-year PFS rate., Results: A total of 34 patients were enrolled. Of the 33 eligible patients and 12 achieved a two-year PFS. Thus, this therapeutic strategy met the criterion for usefulness. The 1-, 2-, 3-, and 5-year PFS rates were 67.0%, 40.2%, 36.9%, and 22.0%, respectively, and the median PFS was 19.5 months. The 1-, 2-, 3- and 5-year survival rates were 90.6%, 71.9%, 64.8%, and 36.5% respectively, and the median survival time was 48.0 months., Conclusion: These results indicate that the insertion of platinum-doublet chemotherapy might prevent the development of acquired resistance to EGFR-TKIs in patients with advanced NSCLC harboring EGFR mutations., (Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.)

Background: The EGFR T790M mutation is the most common mechanism of drug resistance to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors in patients who have lung cancer with an EGFR mutation (EGFR-mutated lung cancer). In preclinical models, the EGFR inhibitor AZD9291 has been shown to be effective against both EGFR tyrosine kinase inhibitor-sensitizing and T790M resistance mutations., Methods: We administered AZD9291 at doses of 20 to 240 mg once daily in patients with advanced lung cancer who had radiologically documented disease progression after previous treatment with EGFR tyrosine kinase inhibitors. The study included dose-escalation cohorts and dose-expansion cohorts. In the expansion cohorts, prestudy tumor biopsies were required for central determination of EGFR T790M status. Patients were assessed for safety, pharmacokinetics, and efficacy., Results: A total of 253 patients were treated. Among 31 patients enrolled in the dose-escalation cohorts, no dose-limiting toxic effects occurred at the doses evaluated. An additional 222 patients were treated in five expansion cohorts. The most common all-cause adverse events were diarrhea, rash, nausea, and decreased appetite. The overall objective tumor response rate was 51% (95% confidence interval [CI], 45 to 58). Among 127 patients with centrally confirmed EGFR T790M who could be evaluated for response, the response rate was 61% (95% CI, 52 to 70). In contrast, among 61 patients without centrally detectable EGFR T790M who could be evaluated for response, the response rate was 21% (95% CI, 12 to 34). The median progression-free survival was 9.6 months (95% CI, 8.3 to not reached) in EGFR T790M-positive patients and 2.8 months (95% CI, 2.1 to 4.3) in EGFR T790M-negative patients., Conclusions: AZD9291 was highly active in patients with lung cancer with the EGFR T790M mutation who had had disease progression during prior therapy with EGFR tyrosine kinase inhibitors. (Funded by AstraZeneca; ClinicalTrials.gov number, NCT01802632.).

Purpose: The biologic characteristics of microenvironmental constituents, especially cancer-associated fibroblasts (CAF), can be key regulators of the cellular sensitivity to molecular-targeted therapy. Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKI) have marked therapeutic effects against non-small cell lung cancer (NSCLC) with EGFR mutations, but some patients have exhibited primary resistance to EGFR-TKIs. We recently reported that podoplanin-positive fibroblasts are associated with a tumor-promoting phenotype of CAFs in lung adenocarcinoma. The aim of this study was to evaluate whether the susceptibility of NSCLC to EGFR-TKIs could be affected by podoplanin-expressing CAFs., Experimental Design: We evaluated the EGFR-TKI sensitivity of EGFR-mutant lung adenocarcinoma cell lines cocultured with podoplanin-expressing CAFs. We also examined the association between the expression of podoplanin in CAFs in surgical specimens and EGFR-TKI response of postoperative recurrent patients with EGFR mutations (N = 106)., Results: Lung adenocarcinoma cell lines became more resistant to EGFR-TKI when cocultured with podoplanin-expressing CAFs, compared with control CAFs in vitro. The knockdown of podoplanin expression on CAFs cancelled the resistance to EGFR-TKIs in cancer cells. Compared with control CAFs, the cancer cells that were cocultured with podoplanin-positive CAFs continued to exhibit significantly higher p-ERK levels after treatment with gefitinib. Furthermore, postoperative recurrent patients with podoplanin-positive CAFs had a significantly lower overall response rate to EGFR-TKIs compared with those with podoplanin-negative CAFs (53% vs. 83%; P < 0.01)., Conclusions: Podoplanin-positive CAFs play an important role in primary resistance to EGFR-TKIs and may be an ideal therapeutic target for use in combination therapy with EGFR-TKIs., (©2014 American Association for Cancer Research.)

Background: The efficacy of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) differs in patients with lung adenocarcinoma harboring EGFR-activating mutations. Although lung adenocarcinoma with EGFR-activating mutations has heterogeneous morphologic features, the predictive role of histologic subtype of lung adenocarcinoma with regard to the effectiveness of EGFR-TKIs in patients with EGFR-activating mutations has not been well defined., Methods: Among 134 postoperative recurrence patients with lung adenocarcinoma harboring EGFR-activating mutation (L858R or exon 19 deletion) treated with EGFR-TKIs, we retrospectively analyzed 61 patients treated with EGFR-TKIs as first-line chemotherapy. All the tumors were classified according to the new histologic classification proposed by the International Association for the Study of Lung Cancer (IASLC), American Thoracic Society (ATS), and European Respiratory Society (ERS) into the following subtypes: lepidic, papillary, acinar, micropapillary, or solid predominant subtype. We evaluated the correlation between the histologic subtype and the clinical efficacy of EGFR-TKIs., Results: In overall response rate, adenocarcinoma with solid predominant subtype is significantly worse than with non-solid predominant subtype (61 vs. 88 %, P = 0.03). The median progression-free survival (PFS) and overall survival after EGFR-TKI treatment were significantly shorter for the patients with solid predominant subtype than for those with non-solid predominant subtype (median PFS of 7.7 vs. 13.5 months, P = 0.002, and median OS of 21.5 vs. 31.0 months, P = 0.028)., Conclusions: This study indicated that among patients with lung adenocarcinoma harboring activating EGFR mutations treated with EGFR-TKIs, solid predominant subtype according to IASLC/ATS/ERS classification is a response predictor for EGFR-TKI.

Adenosquamous carcinoma of the lung (Ad-Sq) is an uncommon subtype with poor prognosis. We analyzed the clinicopathological characteristics of Ad-Sq, focusing the correlation between Epidermal Growth Factor Receptor (EGFR) mutation and clinicopathological factors. A total of 67 cases were selected from September 1992 to May 2011. EGFR mutational analysis (n = 59) was performed by direct sequence. We also performed immunohistochemical staining for EGFR mutated cases using the two mutation-specific antibodies for deletion and L858R. Postoperative 3-year survival rate of Ad-Sq was 58.7%, statistically worse in comparison with adenocarcinoma (58.7% vs. 78.1%, P = 0.038). Twenty-four percent (14/59) were positive for EGFR mutations. Patients who had never been smokers and who were lymphatic permeation positive were seen more frequently in the mutation positive group (P = 0.035, 0.027, respectively). Moreover, the EGFR mutated group tended to have a more positive prognosis than negative. Focusing on the pathological features, the lepidic growth pattern was more frequently seen in the positive group (P = 0.018). Immunoreactivity for the DEL-specific and L858-specific antibody were observed in both adenocarcinoma and squamous cell carcinoma components. Our study demonstrated that EGFR mutated Ad-Sq had similar clinicopathological features as EGFR mutated adenocarcinoma., (© 2013 The Authors. Pathology International © 2013 Japanese Society of Pathology and Wiley Publishing Asia Pty Ltd.)

Introduction: In IPASS (IRESSA Pan-Asia Study), clinically selected patients with pulmonary adenocarcinoma received first-line gefitinib or carboplatin/paclitaxel. This preplanned, exploratory analysis was conducted to increase understanding of the use of surrogate samples, such as serum, versus tumor biopsy samples for determining EGFR mutation status in the Japanese cohort (n = 233)., Methods: EGFR mutations were assessed using tumor tissue-derived DNA (n = 91) and circulating free (cf) DNA from pretreatment serum samples (n = 194)., Results: Fewer patients were EGFR mutation positive when assessed using pretreatment cfDNA (23.7%) versus tumor tissue-derived DNA (61.5%). cfDNA results identified no false positives but a high rate of false negatives (56.9%). There was a significant interaction between cfDNA EGFR mutation status and treatment for progression-free survival (PFS) (p = 0.045). PFS was significantly longer and objective response rate (ORR) higher with gefitinib than carboplatin/paclitaxel in the cfDNA EGFR mutation-positive subgroup (PFS: hazard ratio [HR], 0.29; 95% confidence interval [CI], 0.14-0.60; p < 0.001; ORR: odds ratio [OR], 1.71; 95% CI, 0.48-6.09; 75.0% versus 63.6%; p = 0.40). There was a slight numerical advantage in PFS and ORR for gefitinib over carboplatin/paclitaxel in the cfDNA EGFR mutation-negative subgroup, likely due to the high rate of false negatives within this subgroup., Conclusions: These results merit further investigation to determine whether alternative sources of tumor DNA, such as cfDNA in serum, could be used for determining EGFR mutation status in future; currently, where a sample is available, analysis of tumor material is recommended.

Introduction: This study was performed to determine the incidence rates of resistance factors, i.e., high-level hepatocyte growth factor (HGF) expression, epidermal growth factor receptor (EGFR) T790M secondary mutation, and MET amplification, in tumors with intrinsic and acquired EGFR tyrosine kinase inhibitor (TKI) resistance in EGFR mutant lung cancer., Methods: Ninety-seven specimens from 93 EGFR mutant lung cancer patients (23 tumors with acquired resistance from 20 patients, 45 tumors with intrinsic resistance from 44 patients [nonresponders], 29 sensitive tumors from 29 patients) from 11 institutes in Japan were analyzed. HGF expression, EGFR T790M secondary mutation, and MET amplification were determined by immunohistochemistry, cycleave real-time polymerase chain reaction, and fluorescence in situ hybridization, respectively., Results: High-level HGF expression, EGFR T790M secondary mutation, and MET amplification were detected in 61, 52, and 9% of tumors with acquired resistance, respectively. High-level HGF expression was detected in 29% of tumors with intrinsic resistance (nonresponders), whereas EGFR T790M secondary mutation and MET amplification were detected in 0 and 4%, respectively. HGF expression was significantly higher in tumors with acquired resistance than in sensitive tumors (p < 0.001, Student's t test). Fifty percent of tumors with acquired resistance showed simultaneous HGF expression with EGFR T790M secondary mutation and MET amplification., Conclusions: High-level HGF expression was detected more frequently than EGFR T790M secondary mutation or MET amplification in tumors with intrinsic and acquired EGFR-TKI resistance in EGFR mutant lung cancer in Japanese patients. These observations provide a rationale for targeting HGF in EGFR-TKI resistance in EGFR mutant lung cancer.

We examined the diagnostic accuracy of the cumulative smoking dose for identifying the epidermal growth factor receptor (EGFR) exon 19 deletion and L858R mutation among Japanese patients with non-small-cell lung cancer (NSCLC). EGFR mutations in exon 19 and exon 21 were determined in 1001 NSCLC patients. A receiver-operating characteristic (ROC) curve methodology was applied to estimate the diagnostic accuracy. EGFR mutations were detected in 314 patients (31.4%). A cumulative smoking dose of less than 13 pack-years (PY) was the optimal cut-off point for predicting a positive EGFR mutation status, producing a balance between the sensitivity (73.5%) and the specificity (77%). The area under the ROC curve was 0.77, indicating that the smoking dose had a moderate diagnostic accuracy. The median survival time or the median progression-free survival time of patients who had smoked less than 13 pack-years (PY) were 18.6 and 6.3 months, respectively, while those of patients with equal to or more than 13 PY were 9.6 and 2.4 months, respectively. The overall survival (OS) and progression-free survival (PFS) rates were significantly different between the two groups (OS: hazard ratio [HR] = 0.64, 95% confidence interval [CI] = 0.51-0.80, P = 0.0001) (PFS: HR = 0.58, 95% CI = 0.47-0.71, P < 0.0001). Our study indicated that the smoking dose predicted EGFR mutations with a moderate diagnostic accuracy. Thus, patients who have smoked less than 13 PY might be candidates for gefitinib treatment when EGFR mutation status cannot be determined.

Background: Previous, uncontrolled studies have suggested that first-line treatment with gefitinib would be efficacious in selected patients with non-small-cell lung cancer., Methods: In this phase 3, open-label study, we randomly assigned previously untreated patients in East Asia who had advanced pulmonary adenocarcinoma and who were nonsmokers or former light smokers to receive gefitinib (250 mg per day) (609 patients) or carboplatin (at a dose calculated to produce an area under the curve of 5 or 6 mg per milliliter per minute) plus paclitaxel (200 mg per square meter of body-surface area) (608 patients). The primary end point was progression-free survival., Results: The 12-month rates of progression-free survival were 24.9% with gefitinib and 6.7% with carboplatin-paclitaxel. The study met its primary objective of showing the noninferiority of gefitinib and also showed its superiority, as compared with carboplatin-paclitaxel, with respect to progression-free survival in the intention-to-treat population (hazard ratio for progression or death, 0.74; 95% confidence interval [CI], 0.65 to 0.85; P<0.001). In the subgroup of 261 patients who were positive for the epidermal growth factor receptor gene (EGFR) mutation, progression-free survival was significantly longer among those who received gefitinib than among those who received carboplatin-paclitaxel (hazard ratio for progression or death, 0.48; 95% CI, 0.36 to 0.64; P<0.001), whereas in the subgroup of 176 patients who were negative for the mutation, progression-free survival was significantly longer among those who received carboplatin-paclitaxel (hazard ratio for progression or death with gefitinib, 2.85; 95% CI, 2.05 to 3.98; P<0.001). The most common adverse events were rash or acne (in 66.2% of patients) and diarrhea (46.6%) in the gefitinib group and neurotoxic effects (69.9%), neutropenia (67.1%), and alopecia (58.4%) in the carboplatin-paclitaxel group., Conclusions: Gefitinib is superior to carboplatin-paclitaxel as an initial treatment for pulmonary adenocarcinoma among nonsmokers or former light smokers in East Asia. The presence in the tumor of a mutation of the EGFR gene is a strong predictor of a better outcome with gefitinib. (ClinicalTrials.gov number, NCT00322452.), (2009 Massachusetts Medical Society)

Purpose: This study evaluated whether the presence of epidermal growth factor receptor (EGFR) mutations is a predictive marker for survival benefit from gefitinib and/or a prognostic marker in patients with advanced lung adenocarcinoma., Patients and Methods: Overall survival (OS) was compared between patients with advanced lung adenocarcinoma who began first-line systemic therapy before and after gefitinib approval in Japan (January 1999 to July 2001 and July 2002 to December 2004, respectively). Deletional mutations in exon 19 or the L858R mutation in exon 21 of EGFR were evaluated using high-resolution melting analysis., Results: EGFR mutations were detected in 136 (41%) of the 330 patients included in this study. OS was significantly longer among the EGFR-mutant patients treated after gefitinib approval compared with the OS of patients treated before gefitinib approval (median survival time [MST], 27.2 v 13.6 months, respectively; P < .001), whereas no significant survival improvement was observed in patients without EGFR mutations (MST, 13.2 v 10.4 months, respectively; P = .13). A significant interaction between the presence of EGFR mutations and a survival improvement was seen (P = .045). Among patients treated before gefitinib approval, those with EGFR mutations lived longer than those without EGFR mutations (MST, 13.6 v 10.4 months, respectively; P = .034). The response rates to first-line cytotoxic chemotherapy were not significantly different between patients with and without EGFR mutations (31% v 28%, respectively; P = .50)., Conclusion: EGFR mutations significantly predict both a survival benefit from gefitinib and a favorable prognosis in patients with advanced lung adenocarcinoma.

Purpose: Epidermal growth factor receptor (EGFR) mutations, especially in-frame deletions in exon 19 (DEL) and a point mutation in exon 21 (L858R), predict gefitinib sensitivity in patients with non-small cell lung cancer (NSCLC). In this study, we verified the accuracy of EGFR mutation analysis in small samples by high-resolution melting analysis (HRMA), which is a rapid method using PCR amplification with a dye to analyze the melting curves in NSCLC., Experimental Design: We designed a prospective study to compare the sensitivity and specificity of HRMA and DNA sequencing with laser capture microdissection. Eligible patients with lung lesions were screened by bronchoscopy or percutaneous needle biopsy to histologically confirm the diagnosis, followed by surgical resection of the NSCLC. Small diagnostic specimens were analyzed for EGFR mutations by HRMA, and the surgically resected specimens were examined for mutations by HRMA and DNA sequencing., Results: The analyses for EGFR mutations were conducted in 52 eligible cases of the 92 enrolled patients. EGFR mutations were detected in 18 (34.6%) patients. The results of HRMA from surgically resected specimens as well as DNA sequencing revealed 100% sensitivity and specificity. On the other hand, the sensitivity and specificity of HRMA from the small diagnostic specimens were 83.3% and 100%, respectively., Conclusions: In this study, we showed that HRMA is a highly accurate method for detecting DEL and L858R mutations in patients with NSCLC, although it is necessary to consider the identification of patients with a false-negative result when the analysis is conducted using small samples.

Epidermal growth factor receptor (EGFR) mutations have been reported as a predictive factor for favorable prognosis of gefitinib-treated patients with lung adenocarcinoma. However, its confounding with sex and smoking makes it unclear whether the EGFR mutation is independently associated with prolonged patient survival. In this study, we analyzed a large-scale database to discriminate the survival impact of EGFR mutations against those of sex and smoking after gefitinib therapy. EGFR mutations in exon19 and exon21 named drug-sensitive EGFR mutations were examined to investigate the impact of EGFR mutation, sex, and smoking status on survival of 362 gefitinib-treated patients with lung adenocarcinoma. Drug-sensitive EGFR mutations were detected in 169 patients (46.7%). The multivariate analysis including EGFR, sex, and smoking status showed that drug-sensitive EGFR mutations were significantly related to longer overall survival (OS) (P < 0.001) and progression-free survival (PFS) (P < 0.001). In addition, we investigated the impact of sex and smoking status according to EGFR mutation status, and the impact of EGFR mutation status according to sex and smoking status on survival. Sex and smoking status were not significantly associated with longer OS and PFS according to EGFR mutation status. Drug-sensitive EGFR mutations were significantly associated with longer OS and PFS according to sex or smoking status. Our results indicated that drug-sensitive EGFR mutations were the only independent factor for longer survival of patients treated with gefitinib, suggesting that patient selection based on EGFR mutation status for gefitinib therapy will lead to a better outcome for patients with lung adenocarcinoma.

In lung cancer, somatic mutations of epidermal growth factor receptor (EGFR) are concentrated in exons 18-21, especially in adenocarcinoma (Ad), but these mutations have rarely been reported in small cell lung carcinoma (SCLC). Combined SCLC is rare, and the EGFR mutation status and its relationship to the clinicopathological features of this tumor type have not yet been elucidated. We retrospectively studied six patients with combined SCLC with Ad components among 64 consecutive patients who underwent resection of SCLC. The clinicopathological features of each patient were reviewed, especially for the distribution pattern of the Ad component and lymph node metastases. EGFR mutations were screened by high-resolution melting analysis in each case, and were confirmed by sequencing of each mutation in the microdissected SCLC or Ad components. Regarding EGFR, no specific mutation was detected in five of the six patients, whereas one female patient who had never smoked had a missense mutation. In this case, both the SCLC and Ad components shared the same mutation in exon 21 (L858R). We identified a patient with combined SCLC with Ad sharing an identical EGFR mutation in both the SCLC and Ad components. In addition to the clinicopathological characteristics of this rare histological type of lung cancer, these findings provide useful information for better understanding the biology, natural history and clinical management of SCLC.

Purpose: Epidermal growth factor receptor (EGFR) mutations, especially deletional mutations in exon 19 (DEL) and L858R, predict gefitinib sensitivity in patients with non-small cell lung cancer (NSCLC). In this study, we validated EGFR mutation detection using high-resolution melting analysis (HRMA) and evaluated the associations between EGFR mutations and clinical outcomes in advanced NSCLC patients treated with gefitinib on a larger scale., Experimental Design: The presence of DEL or L858R was evaluated using HRMA and paraffin-embedded tissues and/or cytologic slides from 212 patients. In 66 patients, the results were compared with direct sequencing data., Results: HRMA using formalin-fixed tissues had a 92% sensitivity and a 100% specificity. The analysis was successfully completed in 207 patients, and DEL or L858R mutations were detected in 85 (41%) patients. The response rate (78% versus 8%), time-to-progression (median, 9.2 versus 1.6 months), and overall survival (median, 21.7 versus 8.7 months) were significantly better in patients with EGFR mutations (P < 0.001). Even among the 34 patients with stable diseases, the time-to-progression was significantly longer in patients with EGFR mutations. Patients with DEL (n = 49) tended to have better outcomes than those with L858R (n = 36); the response rates were 86% and 67%, respectively (P = 0.037), and the median time-to-progression was 10.5 and 7.4 months, respectively (P = 0.11)., Conclusions: HRMA is a precise method for detecting DEL and L858R mutations and is useful for predicting clinical outcomes in patients with advanced NSCLC treated with gefitinib.

Purpose: We aimed to identify candidate proteins for tumor markers to predict the response to gefitinib treatment., Experimental Design: We did two-dimensional difference gel electrophoresis to create the protein expression profile of lung adenocarcinoma tissues from patients who showed a different response to gefitinib treatment. We used a support vector machine algorithm to select the proteins that best distinguished 31 responders from 16 nonresponders. The prediction performance of the selected spots was validated by an external sample set, including six responders and eight nonresponders. The results were validated using specific antibodies., Results: We selected nine proteins that distinguish responders from nonresponders. The predictive performance of the nine proteins was validated examining an additional six responders and eight nonresponders, resulting in positive and negative predictive values of 100% (six of six) and 87.5% (seven of eight), respectively. The differential expression of one of the nine proteins, heart-type fatty acid-binding protein, was successfully validated by ELISA. We also identified 12 proteins as a signature to distinguish tumors based on their epidermal growth factor receptor gene mutation status., Conclusions: Study of these proteins may contribute to the development of personalized therapy for lung cancer patients.

Mutations of the epidermal growth factor receptor (EGFR), particularly deletional mutations (DEL) in exon 19 and L858R in exon 21, are reportedly correlated with clinical outcome in patients with non-small cell lung cancer (NSCLC) receiving the EGFR tyrosine kinase inhibitors gefitinib and erlotinib, suggesting that detection of EGFR mutations would have an important role in clinical decision making. We established and validated an easy, inexpensive, and rapid method for detecting DEL and L858R from cytologic material by high-resolution melting analysis (HRMA). Dilution for sensitivity studies revealed that DEL and L858R were detectable in the presence of at least 10% and 0.1% EGFR-mutant cells, respectively. We analyzed 37 archived cytological slides of specimens from 29 patients with advanced NSCLC and compared the results with direct sequencing data obtained previously. Of 37 samples, 34 (92%) yielded consistent results with direct sequencing, 2 were false negative, and 1 was indeterminate. The sensitivity of this analysis was 90% (19/21) and specificity, 100% (15/15). These results suggest that HRMA of archived cytologic specimens of advanced NSCLC is useful for detecting EGFR mutations in clinical practice.

Purpose: To evaluate epidermal growth factor receptor (EGFR) mutations and copy number as predictors of clinical outcome in patients with non-small-cell lung cancer (NSCLC) receiving gefitinib., Patients and Methods: Sixty-six patients with NSCLC who experienced relapse after surgery and received gefitinib were included. Direct sequencing of exons 18 to 24 of EGFR and exons 18 to 24 of ERBB2 was performed using DNA extracted from surgical specimens. Pyrosequencing and quantitative real-time polymerase chain reaction were performed to analyze the allelic pattern and copy number of EGFR., Results: Thirty-nine patients (59%) had EGFR mutations; 20 patients had deletional mutations in exon 19, 17 patients had missense mutations (L858R) in exon 21, and two patients had missense mutations (G719S or G719C) in exon 18. No mutations were identified in ERBB2. Response rate (82% [32 of 39 patients] v 11% [three of 27 patients]; P < .0001), time to progression (TTP; median, 12.6 v 1.7 months; P < .0001), and overall survival (median, 20.4 v 6.9 months; P = .0001) were significantly better in patients with EGFR mutations than in patients with wild-type EGFR. Increased EGFR copy numbers (> or = 3/cell) were observed in 29 patients (44%) and were significantly associated with a higher response rate (72% [21 of 29 patients] v 38% [14 of 37 patients]; P = .005) and a longer TTP (median, 9.4 v 2.6 months; P = .038). High EGFR copy numbers (> or = 6/cell) were caused by selective amplification of mutant alleles., Conclusion: EGFR mutations and increased copy numbers were significantly associated with better clinical outcome in gefitinib-treated NSCLC patients.