Epidermal Growth Factor Receptor Tyrosine Kinase Mutations Research Articles

Epidermal growth factor receptor tyrosine kinase (EGFR-TK) mutation testing in adults with locally advanced or metastatic non-small cell lung cancer: a systematic review and cost-effectiveness analysis.

Non-small cell lung cancer (NSCLC) is the most common form of lung cancer. Some epidermal growth factor receptor tyrosine kinase (EGFR-TK) mutations make tumours responsive to treatment with EGFR-TK inhibitors (EGFR-TKIs) but less responsive to treatment with standard chemotherapy. Patients with NSCLC are therefore tested for EGFR-TK tumour gene mutations to inform treatment decisions. There are a variety of tests available to detect these mutations. The different tests vary in the specific mutations that they attempt to detect, the amount of tumour cells needed for the test to work, the time that it takes to give a result, the error rate of the test, and the cost of the test. To compare the performance and cost-effectiveness of EGFR-TK mutation tests used to identify previously untreated adults with locally advanced or metastatic NSCLC, who may benefit from first-line treatment with TKIs. Twelve databases to August 2012 [including MEDLINE, MEDLINE In-Process & Other Non-Indexed Citations and Daily Update (OvidSP), EMBASE, Cochrane Database of Systematic Reviews (CDSR), Cochrane Central Register of Controlled Trials (CENTRAL), Database of Abstracts of Reviews of Effects (DARE), Health Technology Assessment database (HTA), Science Citation Index (SCI), Latin American and Caribbean Health Sciences Literature (LILACS), BIOSIS Previews, NIHR Health Technology Assessment programme, PROSPERO (International Prospective Register of Systematic Reviews)], research registers and conference proceedings. A web-based survey gathered data on technical performance of EGFR-TK mutation tests. Randomised controlled trials were assessed for methodological quality using the Cochrane risk of bias tool. Diagnostic accuracy studies were assessed using QUADAS-2. There were insufficient data for meta-analysis. For accuracy studies, we calculated sensitivity and specificity together with 95% confidence intervals (CIs). Survival data were summarised as hazard ratios and tumour response data as relative risks, with 95% CIs. The health-economic analysis considered the long-term costs and quality-adjusted life-years (QALYs) associated with different tests followed by treatment with either standard chemotherapy or a TKI. Direct sequencing was taken as the comparator. The de novo model consisted of a decision tree and a Markov model. The survey indicated no differences between tests in batch size, turnaround time, number of failed samples or cost. Six studies provided data on the accuracy of EGFR-TK mutation testing for predicting response to treatment with TKIs. Estimates of accuracy were similar across studies. Six analyses provided data on the clinical effectiveness of TKIs compared with standard chemotherapy. There were no clear differences in the treatment effects reported by different studies, regardless of which EGFR mutation test was used to select patients. Cost-effectiveness analysis using 'Evidence on comparative effectiveness available' and 'Linked evidence' approaches: Therascreen(®) EGFR polymerase chain reaction (PCR) Kit (Qiagen, Venlo, the Netherlands) was both less effective and less costly than direct sequencing of all exon 19-21 mutations at an incremental cost-effectiveness ratio of £32,167 (comparative) and £32,190 (linked) per QALY lost. 'Assumption of equal prognostic value' approach: the lowest total strategy cost was [commercial-in-confidence (CiC) information has been removed] [Sanger sequencing or Roche cobas EGFR Mutation Testing Kit(®) (Roche Molecular Systems, Inc., Branchburg, NJ, USA)] compared with (CiC information has been removed) for the most expensive strategy (fragment length analysis combined with pyrosequencing). The cost-effectiveness analysis assumed that the differences in outcomes between the results of the trials were solely attributable to the different mutation tests used to distinguish between patients; this assumption ignores other factors that might explain this variation. There was no strong evidence that any one EGFR mutation test had greater accuracy than any other test. Re-testing of stored samples from previous studies, where patient outcomes are already known, could be used to provide information on the relative effectiveness of TKIs and standard chemotherapy in patients with EGFR mutation-positive and mutation-negative tumours, where mutation status is determined using tests for which adequate data are currently unavailable. PROSPERO CRD42012002828. The National Institute for Health Research Health Technology Assessment programme.

What is the role of maintenance therapy in the treatment of non-small cell lung cancer?

Introduction Non-small cell lung cancer (NSCLC) remains the leading cause of cancer death in both men and women in the United States. The poor prognosis is largely attributed to advanced stage at diagnosis. Over the past decade, palliative chemotherapy has shown survival benefit in patients with advanced disease [Belani et al. 2005; Martoni et al. 2005; Rudd et al. 2005; Sederholm et al. 2005; Fossella et al. 2003; Non-small Cell Lung Cancer Collaborative Group, 1995]. Platinumbased doublet regimens have been established as the current ‘standard of care’ with improvements in both overall survival (OS) and quality of life [Scagliotti et al. 2008; Belani et al. 2005; Martoni et al. 2005; Rudd et al. 2005; Scagliotti et al. 2002]. Recently, with better understanding of the molecular pathogenesis, targeted agents have been introduced in the treatment of NSCLC. The epidermal growth factor receptor (EGFR) inhibitors have advanced to front-line therapy of patients with tumors that harbor the EGFR tyrosine kinase mutations [Mok et al. 2009; Rosell et al. 2009; Kobayashi et al. 2005]. These are usually continued until disease progression. The addition of bevacizumab to chemotherapy [Reck et al. 2009; Sandler et al. 2006] improves the outcome of a select group of patients with NSCLC but has yet to be adopted worldwide. Although these targeted agents are continued indefinitely until progression, cytotoxic chemotherapeutic intervention has been restricted to four to six cycles in treating patients with advanced NSCLC. Continuation of combination chemotherapy beyond four to six cycles only results in added toxicity without a meaningful improvement in response, progression-free survival (PFS) or OS [Pfister et al. 2004]. The current practice guideline entails a ‘treatment holiday’ and introduction of second-line therapy at the time of disease progression [Azzoli et al. 2009; Pfister et al. 2004]. It is imperative to state that patients who are able to receive second-line interventions represent a select subgroup and again have a modest but significant benefit in overall outcome with treatment. Continued chemotherapeutic intervention with single-agent docetaxel [Fidias et al. 2009] or gemcitabine [Brodowicz et al. 2006] has shown improvement in PFS at the expense of side effects in a subset of patients. The concept of maintenance or prolonged therapy has been adopted in other tumor types such as lymphoma, leukemia and colorectal cancer. With the addition of targeted agents, prolonged administration of bevacizumab has been utilized in NSCLC after initial platinum-based chemotherapy. While this is a biologically rational approach, there is no convincing clinical evidence that patient outcomes are improved with such prolonged administration of this targeted therapy. Recently, three randomized phase III studies have documented improvement in outcome with the use of ‘maintenance therapy’ for patients with advanced stage NSCLC (Table 1) [Cappuzzo et al. 2009; Ciuleanu et al. 2009; Miller et al. 2009]. In this article we discuss current data on maintenance therapy and the implications for routine patient care.

Targeted Therapy for Locally Advanced or Metastatic Non-Small Cell Lung Cancer—Patient Selection Changes the Fate of Gefitinib

Non-small cell lung cancer (NSCLC) presents one of the greatest clinical challenges in oncology. The prevalence of cigarette smoking is the major cause for the high incidence that makes NSCLC the commonest cause of cancer-related death in the western world. Patients frequently present late, with locally advanced or metastatic disease. In this often incurable situation, treatment is delivered with the aim of maximising quality and duration of life. The chosen therapy should, therefore, carry the lowest risk of side-effects in order to maximise clinical benefit. Conventional chemotherapy is typically associated with a long list of possible side effects that may be at best inconvenient, and at worst, dangerous. This group of patients, who may be frail from advanced age, advanced disease stage or additional co-morbidities, would clearly benefit from less toxic but equally effective therapies. Targeted therapeutic agents that inhibit key cell signalling pathways such as the epidermal growth factor receptor (EGFR) have been developed over the last 15 years and have demonstrated proof of principle in clinical trials. The small molecule tyrosine kinase (TK) inhibitors, such as gefitinib, are now established as particularly effective first-line therapy in the subgroup of NSCLC patients whose tumours display EGFR TK mutations that confer sensitivity. Gefitinib has been shown to be non-inferior to docetaxel in second-line therapy, and to have a better side effect profile and more rapid improvement in quality of life than chemotherapy, particularly in patients over 70 years. The publication of landmark studies and consequent changes in licensing have made 2009 the most significant year for gefitinib to date, and we describe the most recent data in the context of relevant translational research. gefitinib, lung cancer, metastatic, advanced, tyrosine kinase inhibitor, epidermal growth factor receptor

9LBA A randomized phase III study comparing gefitinib with carboplatin (CBDCA) plus paclitaxel (TXL) for the first-line treatment of non-small cell lung cancer (NSCLC) with sensitive EGFR mutations: NEJ002 study

prognostic/predictive value of several biomarkers (BM): epidermal growth factor receptor (EGFR) immunohistochemistry (IHC), EGFR fluorescence in situ hybridization (FISH), and EGFR and Kras mutation status. Methods: 743 pts with advanced NSCLC whose disease had not progressed following 4 cycles of 1-line chemotherapy with B were randomized by the interim analysis data cut-off to receive B+E or B+P. B dosing was 15mg/kg every 3 weeks; E dosing was 150mg daily. Maintenance therapy continued until unacceptable toxicity or disease progression. Archival tumor tissue was collected for BM analysis. EGFR FISH and IHC analyses were performed using the PathVysion and PharmDx kits from Abbott-Vysis and DAKO. Analyses of EGFR tyrosine kinase mutations in exons 18−21 and Kras mutations in exons 2 and 3 were performed using DHPLC (denaturing high-performance liquid chromatography) and mutations were validated by sequencing. Results: Biomarker assay results were available for 49.4% of randomized patients. Their demographics were similar to the overall trial population. The PFS HRs for the BM defined subgroups are presented in the table.

Determinants of response to epidermal growth factor receptor tyrosine kinase inhibition in squamous cell carcinoma of the head and neck

Dramatic responses to epidermal growth factor receptor (EGFR) tyrosine kinase (TK) inhibitors may be seen in non-small cell lung cancers (NSCLCs) with a sensitizing mutation of the EGFR TK domain. It is not known how to predict response in patients with squamous cell carcinoma of the head and neck (SCCHN), where EGFR TK mutations are less frequent and where response rates in unselected patients are disappointing. We have characterized the intrinsic sensitivity of a panel of 18 SCCHN cell lines to gefitinib, an EGFR TK inhibitor, and have investigated correlations between putative markers of response and intrinsic sensitivity. Induction of G1 arrest was only seen in cell lines with GI(50) < 1 microM. Expression of EGFR, by three techniques, correlated with sensitivity to gefitinib. ERB-B2 expression appeared to influence sensitivity to gefitinib but ERB-B3 expression did not. While EGFR tyrosine kinase mutations were not detected, EGFR gene amplification was confirmed by fluorescence in situ hybridization in the most sensitive cell line. The number of cytosine adenine dinucleotide repeats in intron 1 of the EGFR gene did not correlate with sensitivity. E-cadherin expression was detected in cell lines with a range of sensitivities, whereas amphiregulin was secreted predominantly by sensitive cell lines. MET expression was an independent predictor of sensitivity to gefitinib, although neither expression nor phosphorylation of insulin-like growth factor 1 receptor correlated with intrinsic resistance. Breast receptor kinase (BRK) was more highly expressed in the sensitive cell lines, but siRNA knockdown of neither BRK nor MET affected sensitivity. Our data suggest that overexpression of EGFR and multiple related cell surface receptors may be associated with sensitivity to gefitinib and that differences between our data and the literature highlight that biomarkers of response are tumour type- and cell line-dependent.

Evaluation of [18F]gefitinib as a molecular imaging probe for the assessment of the epidermal growth factor receptor status in malignant tumors

Gefitinib, an inhibitor of the epidermal growth factor receptor-tyrosine kinase (EGFR-TK), has shown potent effects in a subset of patients carrying specific EGFR-TK mutations in advanced non-small-cell lung cancer. In this study, we asked whether PET with [(18)F]gefitinib may be used to study noninvasively the pharmacokinetics of gefitinib in vivo and to image the EGFR status of cancer cells. Synthesis of [(18)F]gefitinib has been previously described. The biodistribution and metabolic stability of [(18)F]gefitinib was assessed in mice and vervet monkeys for up to 2 h post injection by both micropositron emission tomography (PET)/computed tomography (CT) scans and postmortem ex vivo tissue harvesting. Uptake levels of radiolabeled gefitinib in EGFR-expressing human cancer cell lines with various levels of EGFR expression or mutation status were evaluated both in vivo and in vitro. MicroPET/CT scans in two species demonstrated a rapid and predominantly hepatobiliary clearance of [(18)F]gefitinib in vivo. However, uptake levels of radiolabeled gefitinib, both in vivo and in vitro, did not correlate with EGFR expression levels or functional status. This unexpected observation was due to high nonspecific, nonsaturable cellular uptake of gefitinib. The biodistribution of the drug analogue [(18)F]gefitinib suggests that it may be used to assess noninvasively the pharmacokinetics of gefitinib in patients by PET imaging. This is of clinical relevance, as insufficient intratumoral drug concentrations are considered to be a factor for resistance to gefitinib therapy. However, the highly nonspecific cellular binding of [(18)F]gefitinib may preclude the use of this imaging probe for noninvasive assessment of EGFR receptor status in patients.

P53 Enhances Gefitinib-Induced Growth Inhibition and Apoptosis by Regulation of Fas in Non–Small Cell Lung Cancer

Treatment with gefitinib, a specific inhibitor of epidermal growth factor receptor tyrosine kinase (EGFR-TK), has resulted in dramatic responses in some patients with non-small cell lung cancer (NSCLC). Most patients who respond to gefitinib have EGFR-TK mutations; however, >10% of patients with EGFR-TK mutations do not respond. Similarly, some patients without EGFR-TK mutations respond to this drug, suggesting that other factors determine sensitivity to gefitinib. Aberrations of the tumor suppressor gene p53 are frequently associated with drug resistance. In this study, we investigated the role of p53 in growth-inhibitory and apoptotic effects of gefitinib in the human NSCLC cell lines NCI-H1299 and A549, which have no EGFR-TK mutations. NCI-H1299 cells, which had a p53-null genotype, were more resistant to gefitinib compared with A549 cells, which were wild-type p53 (IC(50), 40 micromol/L in NCI-H1299 and 5 micromol/L in A549). Treatment of A549 with gefitinib resulted in the translocation of p53 from cytosol to nucleus and the up-regulation of Fas, which was localized to the plasma membrane. In the stable H1299 cell line with tetracycline-inducible p53 expression, induced p53 enhanced growth inhibition and apoptosis by gefitinib through the up-regulation of Fas and restoration of caspase activation. A caspase inhibitor, Z-VAD-fmk, reduced these effects. Conversely, inhibition of p53 using antisense oligonucleotide in A549 caused a significant decrease in apoptosis by gefitinib and down-regulation of Fas under the same conditions. In conclusion, p53 may play a role in determining gefitinib sensitivity by regulating Fas expression in NSCLC.

Synchronous multiple primary lung cancers with different response to gefitinib

Synchronous bronchiolo-alveolar cell carcinoma (BAC) in both lungs and squamous cell carcinoma in left lung were found in a 66-year-old male smoker. After two courses of chemotherapy with gemcitabine and carboplatin, the left lung mass had partially resolved, however, the extent of BAC had been increased. When gefitinib was used as a second-line chemotherapy, the consolidation lesions of BAC was improved while the mass of squamous cell carcinoma was aggravated. The analysis of epidermal growth factor receptor-tyrosine kinase (EGFR-TK) mutations showed that BAC had the deletion, delE746-A750 in exon 19, however, squamous cell carcinoma had no mutations. These synchronous tumors with different location, histology, status of EGFR-TK mutations and response to chemotherapy might be caused by different molecular pathogenesis.

Epidermal Growth Factor Receptor Messenger RNA Expression, Gene Dosage, and Gefitinib Sensitivity in Non–Small Cell Lung Cancer

Epidermal growth factor receptor (EGFR) mRNA expression and EGFR gene dosage by quantitative PCR in tumor samples obtained from patients with gefitinib-treated non-small cell lung cancer were analyzed in order to determine the association with treatment outcome, clinical, and biological features [EGFR copy number by fluorescent in situ hybridization (FISH), EGFR tyrosine kinase mutations, and EGFR protein expression]. EGFR mRNA expression was measured by real-time quantitative reverse transcription-PCR in 64 patients, and EGFR gene dosage was analyzed by real-time quantitative PCR in 82 patients from paraffin-embedded specimens. EGFR mRNA expression was higher in responders to gefitinib as compared with nonresponders (P = 0.012). Patients with high EGFR mRNA expression (>5.01) had 43% response probability, whereas patients with low EGFR mRNA expression had 8% response probability (P = 0.006). Patients with high EGFR mRNA expression had longer median progression-free (5.3 versus 2.8 months, P = 0.028) but not overall survival (13.8 versus 10.9 months, P = 0.87). EGFR mRNA expression was higher in FISH-positive patients (P = 0.001) and in patients with positive EGFR immunostaining (P < 0.001) but not in patients with EGFR mutations (P = 0.19). EGFR gene dosage did not predict response (P = 0.54), progression-free (P = 0.73), or overall survival (P = 0.89). EGFR gene dosage was not associated with FISH positivity (P = 0.15), relative mRNA expression (P = 0.27), EGFR mutation status (P = 0.39), and EGFR protein expression (P = 0.35). EGFR mRNA expression is a predictive biomarker for response to gefitinib and to progression-free survival after gefitinib treatment. EGFR gene dosage is neither predictive for response nor progression-free nor overall survival.

Mutations of the epidermal growth factor receptor tyrosine kinase domain and associations with clinicopathological features in non-small cell lung cancer patients

Somatic tyrosine kinase (TK) domain mutations of the epidermal growth factor receptor (EGFR) gene are associated with sensitivity of non-small cell lung cancer (NSCLC) to tyrosine kinase inhibitors (TKI's), however their incidence in distinct populations is not clarified. We sequenced exons 18-21 of the EGFR TK domain from 60 Greek and Czech patients, enrolled in an adjuvant chemotherapy trial following total resection for stages I-IIIa disease. Somatic mutations were found in 9/60 patients (15.0%), several being novel. EGFR mutations were more common in Stage I tumors (p = 0.023), they were also more common in women and never smokers; however, no other significant association of clinicopathological features with mutations was found. Median TTP and OS of patients with and without mutations were 13.2 and 40 months compared to 22.9 and 43.2 months, respectively. These differences were not statistically significant. K-ras (5/60, 8%) and EGFR mutations were found to be mutually exclusive. We identified a wide spectrum of somatic EGFR TK mutations reporting a relatively high incidence (15%) in NSCLC patients of Greek and Czech origin. As ethnicity seems to be a factor for the origin of these mutations, further studies in distinct populations are warranted.

Low incidence of mutations in EGFR kinase domain in Caucasian patients with head and neck squamous cell carcinoma

Somatic mutations in the tyrosine kinase domain of the epidermal growth factor receptor ( EGFR) gene are associated with increased sensitivity to tyrosine kinase inhibitors (TKIs) and are present in 10–30% of non-small cell lung carcinoma depending on ethnic origin. EGFR protein is also overexpressed in about 90% of squamous cell carcinoma of head and neck (HNSCC), and treatment with TKIs has shown clinical benefit in a subgroup of these patients. Recently, EGFR mutations were described in three Asian patients with larynx cancer. We screened for EGFR tyrosine kinase mutations in tumour DNA of 100 patients of Caucasian origin with HNSCC by direct sequencing of the hotspot regions. Only one patient with larynx cancer displayed a novel, somatic EGFR missense mutation, K745R, affecting a highly conserved residue within the ATP cleft. Similar to reports in lung cancer, EGFR kinase domain mutations in HNSCC patients seem to show a lower incidence in patients of Caucasian origin.

Epidermal growth factor receptor activating mutations in Spanish gefitinib-treated non-small-cell lung cancer patients

Background:: North American and Japanese non-small-cell lung cancer (NSCLC) patients with epidermal growth factor receptor (EGFR) activation via tyrosine kinase (TK) mutations respond dramatically to gefitinib treatment. To date, however, the frequency and effect of EGFR TK mutations have not been examined in European patients.Patients and methods:: Eighty-three Spanish advanced NSCLC patients who had progressed after chemotherapy, were treated with compassionate use of gefitinib. Patients were selected on the basis of available tumor tissue. Tumor genomic DNA was retrieved from paraffin-embedded tissue obtained by laser capture microdissection. EGFR mutations in exons 19 and 21 were examined by direct sequencing.Results:: EGFR mutations were found in 10 of 83 (12%) of patients. All mutations were found in adenocarcinomas, more frequently in females (P=0.007) and non-smokers (P=0.01). Response was observed in 60% of patients with mutations and 8.8% of patients with wild-type EGFR (P=0.001). Time to progression for patients with mutations was 12.3 months, compared with 3.6 months for patients with wild-type EGFR (P=0.002). Median survival was 13 months for patients with mutations and 4.9 months for those with wild-type EGFR (P=0.02).Conclusions:: EGFR TK mutational analysis is a novel predictive test for selecting lung adenocarcinoma patients for targeted therapy with EGFR TK inhibitors.

Mutation in the Tyrosine Kinase Domain of Epidermal Growth Factor Receptor Is a Predictive and Prognostic Factor for Gefitinib Treatment in Patients with Non–Small Cell Lung Cancer

Mutations in epidermal growth factor receptor (EGFR) can be used to predict the tumor response of patients receiving gefitinib for non-small cell lung cancer (NSCLC). We investigated the association between mutations in EGFR tyrosine kinase domain and tumor response and survival in gefitinib-treated NSCLC patients. EGFR mutations in exons 18 to 21 were analyzed by DNA sequencing of paraffin-embedded tumor tissues from gefitinib-treated NSCLC patients. The results were correlated with clinical variables. EGFR mutations were found in 61.1% (33 of 54) of cases; response rate and disease control rate were 56.8% and 68.5%, respectively. There was no significant difference in mutation rates between adenocarcinoma (29 of 43) and nonadenocarcinoma (4 of 11; P = 0.085). However, all four nonadenocarcinomas with EGFR mutations had no response to gefitinib. Presence of EGFR mutations was the only independent predictor for disease control (P = 0.003) and tumor response (P = 0.017) in multivariate analysis; positive predictive values were 87.9% and 70.8% and negative predictive values were 61.9% and 69.2%, respectively. In comparison with patients whose tumor was negative for EGFR mutations, patients with EGFR mutations had better progression-free survival (median, 7.6 versus 1.7 months; P = 0.011) and overall survival (median, 14.7 versus 4.7 months; P = 0.046). Mutations in EGFR tyrosine kinase correlate with treatment response and survival in gefitinib-treated NSCLC patients and can be used as a predictive and prognostic factor. Thus, analysis of EGFR tyrosine kinase mutations in lung adenocarcinoma is of clinical significance, as it can permit the customization of treatment with EGFR tyrosine kinase inhibitors.