A phase II trial of gefitinib as first-line therapy for advanced non-small cell lung cancer with epidermal growth factor receptor mutations

Phase II study of preoperative gefitinib in clinical stage I non-small-cell lung cancer

PURPOSE

Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) have proven efficacy in advanced non-small-cell lung cancer (NSCLC). Their role in early-stage NSCLC has not been established. Our purpose was to explore the use of preoperative gefitinib in clinical stage I NSCLC to assess tumor response, toxicity, and clinical and molecular predictors of response.

PATIENTS AND METHODS

Patients received gefitinib 250 mg/d for up to 28 days, followed by mediastinoscopy and surgical resection in an open-label, single-arm study. Tumor response was evaluated by Response Evaluation Criteria in Solid Tumors. Blood samples and tumor biopsies were collected and analyzed for transforming growth factor alpha level, EGFR protein expression, EGFR gene copy number, and EGFR (exon 19 to 21) and KRAS mutations.

RESULTS

Thirty-six patients completed preoperative treatment (median duration, 28 days; range, 27 to 30 days). Median follow-up time is 2.1 years (range, 0.86 to 3.46 years). Three patients experienced grade 3 toxicities (rash, diarrhea, and elevated ALT). Tumors demonstrated EGFR-positive protein expression in 83%, high gene copy number in 59%, EGFR mutations in 17%, and KRAS mutations in 17%. Tumor shrinkage was more frequent among women and nonsmokers. Partial response was seen in four patients (11%), and disease progression was seen in three patients (9%). The strongest predictor of response was EGFR mutation.

CONCLUSION

Preoperative window therapy with gefitinib is a safe and feasible regimen in early NSCLC and provides a trial design that may better inform predictors of treatment response or sensitivity.

Targeted therapies in the treatment of advanced/metastatic NSCLC

The treatment of advanced non-small cell lung cancer (NSCLC) has evolved substantially during the last years. Chemotherapy remains the cornerstone of treatment and prolongs survival with a positive impact on quality of life. However, we seem to have reached a plateau of activity in the treatment of NSCLC. Recently, the addition of bevacizumab or cetuximab to chemotherapy doublets has improved the outcome in selected patients with advanced NSCLC. Furthermore, the use of erlotinib and gefitinib is an alternative for second line treatment. Advances in our understanding of molecular biology of cancer and mechanisms of tumourigenesis have further enabled the discovery of several potential molecular targets and development of novel 'targeted therapies'. The purpose of this study is to review current data on the role of targeted therapies in the treatment of advanced NSCLC.

Amphiregulin promotes BAX inhibition and resistance to gefitinib in non-small-cell lung cancers

Molecular resistance mechanisms affecting the efficiency of receptor tyrosine kinase inhibitors such as gefitinib in non-small-cell lung cancer (NSCLC) cells are not fully understood. Amphiregulin (Areg) overexpression has been proposed to predict NSCLC resistance to gefitinib and we have established that Areg-overexpressing H358 NSCLC cells resist apoptosis. Here, we demonstrate that Areg prevents gefitinib-induced apoptosis in NSCLC cells. We show that H358 cells are resistant to gefitinib in contrast to H322 cells, which do not overexpress Areg. Inhibition of Areg expression by small-interfering RNAs (siRNAs) restores gefitinib sensitivity in H358 cells, whereas addition of recombinant Areg confers resistance in H322 cells. Areg knockdown overcomes resistance to gefitinib and induced apoptosis in NSCLC H358 cells in vitro and in vivo. Under gefitinib treatment, Areg decreases the expression of the proapoptotic protein BAX, inhibits its conformational change and its mitochondrial translocation. Thus, in the presence of Areg, gefitinib-mediated apoptosis is reduced because BAX is sequestered in the cytoplasm. This suggests that treatments using epidermal growth factor receptor (EGFR) inhibitors may be poorly efficient in patients with elevated levels of Areg. These findings indicate the need for inhibition of Areg to enhance the efficiency of the EGFR inhibitors in patients suffering NSCLC.

Somatic EGFR mutations and efficacy of tyrosine kinase inhibitors in NSCLC

Early clinical studies of tyrosine kinase inhibitors (TKIs) that target the EGFR in patients with advanced non-small-cell lung cancer (NSCLC) showed that some patients experienced rapid, durable, complete or partial responses. These data were the basis for attempts to identify specific subgroups of patients who would further benefit from these agents. The discovery of somatic mutations in EGFR that correlated with sensitivity to TKIs identified a plausible explanation for these observations. Clinical and pathological factors such as female sex, never having smoked, Asian origin and adenocarcinoma histology correlate with the presence of EGFR mutations and objective responses to TKIs in patients with NSCLC. Recent studies in metastatic colorectal cancer highlighted that somatic mutations in KRAS represent a negative predictor of response to anti-EGFR monoclonal antibodies; KRAS mutations also represent an important mechanism of resistance to TKIs in NSCLC. Many large clinical studies are currently investigating the predictive and prognostic value of EGFR mutational status and other candidate biomarkers. We summarize the literature and present an overview of the field of anti-EGFR therapy in NSCLC, focusing on the influence of somatic EGFR mutations on selection of patients for TKI therapy and the influence of EGFR pathway regulation.

Clinical features and outcome of patients with non-small-cell lung cancer who harbor EML4-ALK

PURPOSE

The EML4-ALK fusion oncogene represents a novel molecular target in a small subset of non-small-cell lung cancers (NSCLC). To aid in identification and treatment of these patients, we examined the clinical characteristics and treatment outcomes of patients who had NSCLC with and without EML4-ALK.

PATIENTS AND METHODS

Patients with NSCLC were selected for genetic screening on the basis of two or more of the following characteristics: female sex, Asian ethnicity, never/light smoking history, and adenocarcinoma histology. EML4-ALK was identified by using fluorescent in situ hybridization for ALK rearrangements and was confirmed by immunohistochemistry for ALK expression. EGFR and KRAS mutations were determined by DNA sequencing.

RESULTS

Of 141 tumors screened, 19 (13%) were EML4-ALK mutant, 31 (22%) were EGFR mutant, and 91 (65%) were wild type (WT/WT) for both ALK and EGFR. Compared with the EGFR mutant and WT/WT cohorts, patients with EML4-ALK mutant tumors were significantly younger (P < .001 and P = .005) and were more likely to be men (P = .036 and P = .039). Patients with EML4-ALK-positive tumors, like patients who harbored EGFR mutations, also were more likely to be never/light smokers compared with patients in the WT/WT cohort (P < .001). Eighteen of the 19 EML4-ALK tumors were adenocarcinomas, predominantly the signet ring cell subtype. Among patients with metastatic disease, EML4-ALK positivity was associated with resistance to EGFR tyrosine kinase inhibitors (TKIs). Patients in the EML4-ALK cohort and the WT/WT cohort showed similar response rates to platinum-based combination chemotherapy and no difference in overall survival.

CONCLUSION

EML4-ALK defines a molecular subset of NSCLC with distinct clinical characteristics. Patients who harbor this mutation do not benefit from EGFR TKIs and should be directed to trials of ALK-targeted agents.

Factors underlying sensitivity of cancers to small-molecule kinase inhibitors

Selective small-molecule kinase inhibitors have emerged over the past decade as an important class of anti-cancer agents, and have demonstrated impressive clinical efficacy in several different diseases, including relatively common malignancies such as breast and lung cancer. However, clinical benefit is typically limited to a fraction of treated patients. Genomic features of individual tumours contribute significantly to such clinical responses, and these seem to vary tremendously across patients. Additional factors, including pharmacogenomics, the tumour microenvironment and rapidly acquired drug resistance, also contribute to the clinical sensitivity of various cancers, and should be considered and applied in the development and use of new kinase inhibitors.

Combined survival analysis of prospective clinical trials of gefitinib for non-small cell lung cancer with EGFR mutations

PURPOSE

Somatic mutations of the epidermal growth factor receptor (EGFR) gene are associated with an increased response to gefitinib in patients with non-small cell lung cancer. We have examined the impact of gefitinib on progression-free survival and overall survival in patients with EGFR mutation-positive non-small cell lung cancer.

EXPERIMENTAL DESIGN

We searched for all clinical trials that prospectively evaluated the efficacy of gefitinib for advanced non-small cell lung cancer with EGFR mutations in Japan. We did a combined analysis based on individual patient data from the identified trials.

RESULTS

Seven eligible trials were identified for a total of 148 non-small cell lung cancer patients with EGFR mutations. The overall response rate to gefitinib was 76.4% [95% confidence interval (95% CI), 69.5-83.2]. The median progression-free survival and overall survival were 9.7 months (95% CI, 8.2-11.1) and 24.3 months (95% CI, 19.8-28.2), respectively. Good performance status and chemotherapy-naïve status were significantly associated with a longer progression-free survival or overall survival. Of the 148 patients, 87 received gefitinib as a first-line therapy, whereas 61 received systemic chemotherapy before gefitinib treatment. The median progression-free survival after the start of first-line therapy was significantly longer in the gefitinib-first group than in the chemotherapy-first group (10.7 versus 6.0 months; P < 0.001), whereas no significant difference in median overall survival was apparent between the two groups (27.7 versus 25.7 months; P = 0.782).

CONCLUSIONS

Gefitinib monotherapy confers substantial clinical benefit in terms of progression-free survival and overall survival in non-small cell lung cancer patients with EGFR mutations. Randomized trials comparing chemotherapy with gefitinib as a first-line treatment are warranted in such patients.

The CTC-chip: an exciting new tool to detect circulating tumor cells in lung cancer patients

Circulating tumor cells (CTCs) are rare cells that originate from a malignancy and circulate freely in the peripheral blood. The ability to capture and study CTCs is an emerging field with implications for early detection, diagnosis, determining prognosis and monitoring of cancer, as well as for understanding the fundamental biology of the process of metastasis. Here, we review the development and initial clinical studies with a novel microfluidic platform for isolating these cells, the CTC-chip, and discuss its potential uses in the study of lung cancer.

Noninvasive detection of EGFR T790M in gefitinib or erlotinib resistant non-small cell lung cancer

PURPOSE

Tumors from 50% of epidermal growth factor receptor (EGFR) mutant non-small cell lung cancer patients that develop resistance to gefitinib or erlotinib will contain a secondary EGFR T790M mutation. As most patients do not undergo repeated tumor biopsies we evaluated whether EGFR T790M could be detected using plasma DNA.

EXPERIMENTAL DESIGN

DNA from plasma of 54 patients with known clinical response to gefitinib or erlotinib was extracted and used to detect both EGFR-activating and EGFR T790M mutations. Forty-three (80%) of patients had tumor EGFR sequencing (EGFR mutant/wild type: 30/13) and seven patients also had EGFR T790M gefitinib/erlotinib-resistant tumors. EGFR mutations were detected using two methods, the Scorpion Amplification Refractory Mutation System and the WAVE/Surveyor, combined with whole genome amplification.

RESULTS

Both EGFR-activating and EGFR T790M were identified in 70% of patients with known tumor EGFR-activating (21 of 30) or T790M (5 of 7) mutations. EGFR T790M was identified from plasma DNA in 54% (15 of 28) of patients with prior clinical response to gefitinib/erlotinib, 29% (4 of 14) with prior stable disease, and in 0% (0 of 12) that had primary progressive disease or were untreated with gefitinib/erlotinib.

CONCLUSIONS

EGFR T790M can be detected using plasma DNA from gefitinib- or erlotinib-resistant patients. This noninvasive method may aid in monitoring drug resistance and in directing the course of subsequent therapy.

Theme: Oncology - Molecular mechanisms determining the efficacy of EGF receptor-specific tyrosine kinase inhibitors help to identify biomarker candidates

Non-small-cell lung cancer is a major subtype of lung cancer, which is the most common and fatal cancer in the world. Gefitinib (Iressa™) and later erlotinib (Tarceva™), specific tyrosine kinase inhibitors for EGF receptors (EGFRs), have been demonstrated to be effective for some non-small-cell lung cancer patients and used in clinics as pioneers of molecule-based targeted drugs for cancer. There has been an urgent need to develop biomarkers and to select appropriate patients who should benefit from treatment with these drugs because of the high sensitivity of target cancer cells. However, problems of acquired resistance after long-term treatment with these drugs have been recognized. Emerging evidence indicates that the efficacy of these drugs is partly dependent on somatic mutations in the EGFR. In this review, we summarize recent understandings of the molecular mechanisms that determine the efficacy of EGFR–tyrosine kinase inhibitors. Towards the end of this article, we discuss recent ongoing projects validating potential biomarkers and future prospects.

Pilot study of gefitinib and fulvestrant in the treatment of post-menopausal women with advanced non-small cell lung cancer

INTRODUCTION

Estrogen receptor beta (ERbeta) has been detected in non-small cell lung cancer (NSCLC) cell lines and tumor specimens. The ER down-regulator, fulvestrant, blocked estradiol-stimulation of tumor growth and gene transcription in NSCLC preclinical models and showed additive effects with the epidermal growth factor receptor (EGFR) inhibitor gefitinib. The safety and tolerability of combination therapy with the EGFR inhibitor, gefitinib, and fulvestrant was explored.

METHODS

Post-menopausal women with advanced NSCLC received gefitinib 250 mg po daily and fulvestrant 250 mg IM monthly.

RESULTS

Twenty-two patients were enrolled. Eight patients had adenocarcinoma, six NSCLC-NOS, four squamous cell, and four BAC. Seven patients were never-smokers. Eight patients received > or =2 lines of prior chemotherapy, six received one prior chemotherapy, and eight were treatment-naïve. One patient experienced grade 4 dyspnea possibly related to treatment; all other grade 3/4 toxicities were unrelated to treatment. Twenty patients were evaluable for response: three partial responses (PRs) were confirmed (response rate of 15%, 95% CI: 5-36%). The median progression-free survival (PFS), overall survival (OS), and estimated 1-year OS were 12 weeks (3-112 weeks), 38.5 weeks (7-135 weeks), and 41% (95% CI: 20-62%), respectively. Survival outcomes did not differ by prior lines of therapy. A subset analysis revealed that OS in the eight patients whose tumors exhibited at least 60% ERbeta nuclear IHC staining measured 65.5 weeks, while that of the five patients with ERbeta staining of less than 60% was 21 weeks. One patient with bronchioalveolar carcinoma (BAC) and a PR had an EGFR L858R mutation in exon 21. There was no correlation between ERbeta IHC expression and histology or smoking history.

CONCLUSIONS

Combination therapy with gefitinib and fulvestrant in this population was well tolerated and demonstrated disease activity.

EGFR-targeted therapies in lung cancer: predictors of response and toxicity

The EGFR pathway has emerged as a key target in non-small-cell lung cancer. EGF receptor (EGFR) inhibition in non-small-cell lung cancer is achieved via small molecular tyrosine kinase inhibitors, such as erlotinib or gefitinib, or monoclonal antibodies such as cetuximab. A growing body of evidence is identifying potential molecular predictors of response and toxicity. This includes tumor-related molecular markers, such as EGFR mutation and copy number, as well as germline markers such as polymorphisms in EGFR or EGFR pathway-related genes. This review focuses on the current state of knowledge of predictors of response and toxicity to EGFR inhibitors in lung cancer.

Gefitinib for the treatment of non-small-cell lung cancer

Gefitinib is an orally bioavailable, EGF receptor tyrosine kinase inhibitor and was the first targeted drug to be approved for non-small-cell lung cancer (NSCLC). Identification of objective tumor regressions with gefitinib in NSCLC patients has resulted in intense, worldwide clinical and basic research directed toward finding the optimal use of gefitinib in NSCLC. A recent large international Phase III study (IRESSA NSCLC Trial Evaluating Response and Survival Against Taxotere [INTEREST]) comparing gefitinib and docetaxel in unselected pretreated patients showed equivalent survival with better tolerability and quality of life. In addition, a Phase III study (WJTOG0203) evaluating gefitinib as sequential therapy after platinum-doublet chemotherapy showed the improved progression-free survival time. Furthermore, a large-scale randomized study (IRESSA Pan-Asia study [IPASS]) comparing gefitinib monotherapy with carboplatin/paclitaxel for previously untreated patients with adenocarcinoma who were never- or light-smokers showed an improved progression-free survival time in the gefitinib arm. A smaller Phase III study of pretreated Japanese patients (V-15-32) also demonstrated no difference in overall survival compared with docetaxel, with a statistically greater overall response rate. Somatic mutations in the EGFR gene, the target of gefitinib, were associated with dramatic and durable regressions in patients with NSCLC. Currently, investigators are trying to determine the optimal approach to select patients for treatment with gefitinib. This article aims to briefly summarize the profile of gefitinib, EGFR mutations, landmark trials with gefitinib and, also, ongoing trials that may herald an era of individualized therapy in at least some NSCLC patients.

First-line gefitinib for patients with advanced non-small-cell lung cancer harboring epidermal growth factor receptor mutations without indication for chemotherapy

PURPOSE

This multicenter phase II study was undertaken to investigate the efficacy and feasibility of gefitinib for patients with advanced non-small-cell lung cancer (NSCLC) harboring epidermal growth factor receptor (EGFR) mutations without indication for chemotherapy as a result of poor performance status (PS).

PATIENTS AND METHODS

Chemotherapy-naïve patients with poor PS (patients 20 to 74 years of age with Eastern Cooperative Oncology Group PS 3 to 4, 75 to 79 years of age with PS 2 to 4, and >or= 80 years of age with PS 1 to 4) who had EGFR mutations examined by the peptide nucleic acid-locked nucleic acid polymerase chain reaction clamp method were enrolled and received gefitinib (250 mg/d) alone.

RESULTS

Between February 2006 and May 2007, 30 patients with NSCLC and poor PS, including 22 patients with PS 3 to 4, were enrolled. The overall response rate was 66% (90% CI, 51% to 80%), and the disease control rate was 90%. PS improvement rate was 79% (P < .00005); in particular, 68% of the 22 patients improved from >or= PS 3 at baseline to <or= PS 1. The median progression-free survival, median survival time, and 1-year survival rate were 6.5 months, 17.8 months, and 63%, respectively. No treatment-related deaths were observed.

CONCLUSION

This is the first report indicating that EGFR mutation-positive patients with extremely poor PS benefit from first-line gefitinib. Because there previously has been no standard treatment for these patients with short life expectancy other than best supportive care, examination of EGFR mutations as a biomarker is recommended in this patient population.

Molecular perspectives on the non-responder phenomenon

With the advent of targeted therapies promising to revolutionise the nature and success of patient care, the field of clinical oncology is facing a highly exciting future. While much of this enthusiasm comes from the hope for improved patient outcomes, a review of clinical response/relapse rates for current therapies provides a more sobering perspective. Given that the majority of patients are intrinsically resistant to the therapeutic potential of these molecules, efforts are now directed at characterising such non-responsive system behaviour and causative molecular insults. Testament to this is an expanding catalogue of target and system-based aberrations, often defined through retrospective analyses of clinical tissue and associated outcome data. What has emerged is a complex picture, where numerous potential sources of cancer-specific aberration can contribute to refractory tumour behaviour. Clinicians, regulators and sponsors must now collaborate to determine how such knowledge should be used to enhance the clinical decision process and associated regulatory guidance.

Genetic heterogeneity of EGFR mutation in pleomorphic carcinoma of the lung: response to gefitinib and clinical outcome

Somatic epidermal growth factor receptor (EGFR) mutations in exons 19 and 21 have been found in non-small cell lung cancer (NSCLC) and are associated with the therapeutic response to gefitinib in patients with advanced NSCLC. We report a case of pleomorphic carcinoma of the lung with different EGFR mutations. Prior to gefitinib treatment, an exon 19 deletion of EGFR mutation was positive in the specimens obtained from pleural effusion and left cervical lymph node, histologically proven to be adenocarcinoma. However, the response to gefitinib was poor and the patient died of progressive disease 4 months after the initiation of gefitinib therapy. Postmortem examination revealed the major histological component to be of the sarcomatoid or pleomorphic type with scant mixed adenocarcinoma, resulting in a histological diagnosis of pleomorphic carcinoma of the lung. Although the adenocarcinomatous tissue was still positive for exon 19 deletion of EGFR mutation alone, sarcomatous components had both the exons 19 deletion and 20 T790M mutation concomitantly, thought to be a gefitinib resistance mutation. Pulmonary pleomorphic carcinoma is a rare NSCLC composed of biphasic and heterogeneous malignant cell populations. The present case suggested that expression of different EGFR mutations is related to the biphasic histological appearance in pulmonary pleomorphic carcinoma.

Correlation of F-18 fluorodeoxyglucose-positron emission tomography maximal standardized uptake value and EGFR mutations in advanced lung adenocarcinoma

OBJECTIVE

Epidermal growth factor receptor (EGFR) mutations in lung adenocarcinoma are involved in the tumorigenesis and regulation of cell metabolism via Akt signaling. F-18 fluorodeoxyglucose-positron emission tomography ([(18)F]FDG PET), a functional imaging modality, can be used to measure tumor cell metabolism. Thus, in this study, we hypothesize that there exist correlations between EGFR mutation status and [(18)F]FDG uptake of advanced lung adenocarcinoma.

METHODS

From May 2004 to April 2008, patients with stage IIIB or IV lung adenocarcinoma who underwent [(18)F]FDG PET and EGFR mutation analysis before receiving any treatment were eligible to participate in this study. The association of EGFR mutation status with patient characteristics and the SUV(MAX) from the [(18)F]FDG PET was evaluated. Multivariate logistic regression analysis was used to analyze predictors of EGFR mutations.

RESULTS

Seventy-seven lung adenocarcinoma patients were included in this study. EGFR mutations were identified in 49 (64%) of the patients. The [(18)F]FDG uptake was significantly higher in EGFR-mutant (mean SUV(MAX) = 10.5 +/- 4.7) than wild-type (8.0 +/- 3.3) lung adenocarcinoma patients (P = 0.008). The median SUV(MAX) was 9.5, and patients with an SUV(MAX) >or= 9.5 were more likely to harbor EGFR mutations (P = 0.009). In the multivariate analysis, an SUV(MAX) >or= 9.5 remained a statistically significant predictor of EGFR mutations (P = 0.005).

CONCLUSIONS

Among Asian patients with advanced lung adenocarcinoma, those with higher SUV(MAX) on the [(18)F]FDG PET are more likely to carry EGFR mutations.

The role of the epidermal growth factor receptor tyrosine kinase inhibitors as therapy for advanced, metastatic, and recurrent non-small-cell lung cancer: a Canadian national consensus statement

PURPOSE

To provide consensus recommendations on the use of epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIS) in patients with advanced or meta-static non-small-cell lung cancer (NSCLC).

METHODS

Using a systematic literature search, phase II trials, randomized phase III trials, and meta-analyses were identified for inclusion.

RESULTS

A total of forty-six trials were included. Clear evidence is available that EGFR-TKIS should not be administered concurrently with platinum-based chemotherapy as first-line therapy in advanced or metastatic nsclc. Evidence is currently insufficient to recommend single-agent EGFR-TKIS as first-line therapy either in unselected populations or in populations selected on the basis of molecular or clinical characteristics. Following failure of platinum-based chemotherapy, the evidence suggests that second-line EGFR-TKIS or second-line chemotherapy result in similar survival. Quality of life and symptom improvement for patients treated with an EGFR-TKI appear better than they do for patients treated with second-line docetaxel. Sequence of therapy may not appear to be important, but if survival is the outcome of interest, the goal should be to optimize the number of patients receiving three lines of therapy. Based on available data, molecular markers and clinical characteristics do not appear to be predictive of a differential survival benefit from an EGFR-TKI and therefore those factors should not be used to select patients for EGFR-TKI therapy.

CONCLUSIONS

The EGFR-TKIS represent an additional therapy in the treatment of advanced or metastatic NSCLC. The results of ongoing clinical trials may define the optimal role for these agents and the effectiveness of combinations of these agents with other targeted agents.

Reduced Erlotinib sensitivity of epidermal growth factor receptor-mutant non-small cell lung cancer following cisplatin exposure: a cell culture model of second-line erlotinib treatment

PURPOSE

Epidermal growth factor receptor (EGFR) kinase inhibitors induce dramatic clinical responses in a subset of non-small cell lung cancer (NSCLC) patients with advanced disease, and such responses are correlated with the presence of somatic activating mutations within the EGFR kinase domain. Consequently, one of these inhibitors, erlotinib, has been Food and Drug Administration-approved as a second- or third-line treatment for chemotherapy-refractory advanced NSCLC. However, responses are typically relatively short-lived due to acquired drug resistance, prompting studies to determine whether first-line treatment with EGFR inhibitors could provide greater clinical benefit. NSCLC-derived cell lines have provided a powerful system for modeling EGFR mutation-correlated sensitivity to EGFR inhibitors and for modeling mechanisms of acquired drug resistance that are observed clinically.

EXPERIMENTAL DESIGN

In a cell culture model of an erlotinib-sensitive EGFR-mutant NSCLC cell line, we tested the hypothesis that prior exposure to platinum agents, a standard component of NSCLC chemotherapy treatment, affects the subsequent response to erlotinib.

RESULTS

Indeed, NSCLC cells initially selected for growth in cisplatin exhibit 5-fold reduced sensitivity to erlotinib, even after propagating the cisplatin-treated cells in the absence of cisplatin for several months. This lingering effect of cisplatin exposure appears to reflect changes in PTEN tumor suppressor activity and persistent EGFR-independent signaling through the phosphatidylinositol 3-kinase/AKT survival pathway.

CONCLUSIONS

These preclinical findings suggest that first-line chemotherapy treatment of EGFR-mutant NSCLCs may reduce the benefit of subsequent treatment with EGFR kinase inhibitors and should prompt further clinical investigation of these inhibitors as a first-line therapy in NSCLC.

Selective targeting of the tumour vasculature

Selective targeting of the tumour vasculature in the treatment of solid organ malignancies is an alternative to conventional chemotherapy treatment. As the tumour progressively increases in size, angiogenesis or the formation of new vasculature is essential to maintain the tumour's continual growth and survival. Therefore disrupting this angiogenic process or targeting the neovasculature can potentially hinder or prevent further tumour expansion. Many anti angiogenic agents have been investigated with many currently in clinical trials and exhibiting varied results. Vascular disrupting agents such as the Combretastatins and OXi 4503 have shown promising preclinical results and are currently being examined in clinical trials.

Overview of gefitinib in non-small cell lung cancer: an Asian perspective

Clinical experience with the EGFR-TKI gefitinib in Asian patients with NSCLC will be reviewed, both in patients who have previously failed chemotherapy and in the first-line setting (gefitinib is currently not licensed for first-line treatment). Tolerability and specific adverse events in patients of Asian origin will be discussed. Differing objective response rates between patients of Asian and non-Asian origin when treated with gefitinib (and standard cytotoxics) will also be discussed along with EGFR mutations and drug resistance. Reports of Phase II/III clinical experience with gefitinib 250 mg/day in Asia were identified by searching in Medline and ASCO databases for publications between 1993 and 2008. Defined search criteria included (gefitinib OR Iressa OR ZD1839) AND NSCLC AND (Asia OR Japan OR China OR Taiwan OR Korea) or 'Clinical trial' type, with additional searches, including AND 'interstitial lung disease (ILD)' or 'EGFR mutation'. Numerous Phase II/III trials including patients of Asian origin with previously treated advanced NSCLC report a consistent clinical benefit of gefitinib. Gefitinib is generally well tolerated by patients with NSCLC although the incidence of ILD in Japanese patients must be noted. Studies analyzing EGFR mutations indicate that these mutations occur at a much higher rate in patients of Asian origin than in non-Asian patients. Data from several studies indicate that EGFR mutation-positive patients of Asian origin have better efficacy outcomes with first-line gefitinib when compared with those who are EGFR mutation-negative. Research is ongoing to evaluate the role of tailoring patients' treatment according to their genetic phenotype.

EGFR Inhibition in the Treatment of Non-Small Cell Lung Cancer

Epidermal growth factor receptor (EGFR) inhibitors have introduced the concept of targeted therapy to the treatment of non-small cell lung cancer (NSCLC). These agents appear most effective in patients with tumors that are highly dependent on EGFR signaling pathways, a population that disproportionately includes females, nonsmokers, individuals of East Asian origin, and patients with adenocarcinoma histology. Currently available EGFR-inhibiting drugs include the tyrosine kinase inhibitors (TKIs) erlotinib, gefitinib, and lapatinib, which are administered orally and interfere with the intracellular tyrosine kinase domain, and the monoclonal antibodies (mAbs) cetuximab and panitumumab, which are administered intravenously and interfere with extracellular ligand binding. While the use of EGFR TKIs as monotherapy prolongs survival in metastatic NSCLC, they have demonstrated no benefit when added to conventional, cytotoxic chemotherapy. In contrast, the anti-EGFR mAb cetuximab appears most effective when combined with chemotherapy or radiation. Despite dramatic initial responses to treatment in some cases, NSCLC eventually becomes resistant to EGFR inhibition. Possible mechanisms include secondary mutations that interfere with drug binding, oncogenic pathways driven by other receptor tyrosine kinases, and independent activity of downstream signaling molecules. Efforts to overcome such resistance include irreversibly binding EGFR TKIs, multi-targeted TKIs, and combinations with chemotherapy, radiation, and other targeted therapies.

Association of epidermal growth factor receptor (EGFR) gene mutations with EGFR amplification in advanced non-small cell lung cancer

Somatic mutations in the epidermal growth factor receptor (EGFR) gene are associated with the response to EGFR tyrosine kinase inhibitors in patients with non-small cell lung cancer (NSCLC). Increased EGFR copy number has also been associated with sensitivity to these drugs. However, given that it is often difficult to obtain sufficient amounts of tumor tissue for genetic analysis from patients with advanced NSCLC, the relationship between these two types of EGFR alterations has remained unclear. We have now evaluated EGFR mutation status both by direct sequencing and with a high-sensitivity assay, the Scorpion-amplification-refractory mutation system, and have determined EGFR copy number by fluorescence in situ hybridization (FISH) analysis in paired tumor specimens obtained from 100 consecutive patients with advanced NSCLC treated with chemotherapy. EGFR mutations or FISH positivity (EGFR amplification or high polysomy) were apparent in 18% (18/100) and 32% (32/100) of patients, respectively. The Scorpion-amplification-refractory mutation system was more sensitive than direct sequencing for the detection of EGFR mutations. Furthermore, EGFR mutations were associated with EGFR amplification (P = 0.009) but not with FISH positivity (P = 0.266). Our results therefore suggest the existence of a significant association between EGFR mutation and EGFR amplification in patients with advanced NSCLC.

EGFR mutations and HER2/3 protein expression and clinical outcome in Chinese advanced non-small cell lung cancer patients treated with gefitinib

BACKGROUND

To assess the role of various epidermal growth factor receptor (EGFR) mutations and HER2/3 protein expression as predictive markers of responsiveness to gefitinib therapy in Chinese patients with advanced non-small cell lung cancer (NSCLC).

METHODS

A total of 106 Chinese NSCLC patients who had failed at least one chemotherapy regimen received gefitinib 250 mg once daily. All the 106 tumors from these patients were screened for mutations in the EGFR exons 18-24, and 84 tumors were studied by immunohistochemistry for HER2/3 expression and correlated with clinical treatment outcome.

RESULTS

Patients with EGFR mutations had a significantly higher overall response rate (ORR), longer time to progression (TTP) and overall survival (OS) compared with those with wild-type receptor. No difference in ORR was observed between patients with exon 19 deletion and patients with other EGFR mutations. ORR in HER2-positive patients was significantly higher than in the HER2-negative group, irrespective of EGFR mutational status, and a trend for better ORR was observed for HER3-positive patients. HER2 and HER3 expression levels were not associated with any difference in terms of TTP and OS. Nevertheless, when considering the subgroups of non-responders to gefitinib, median TTP in patients with mutated EGFR was significantly longer than in those with no mutations (8.0 vs. 3.0 months, P = 0.0065). EGFR-mutated patients had no significant difference in ORR, TTP and OS according to HER2 and/or HER3 expression.

CONCLUSIONS

EGFR mutations are effective predictors for gefitinib efficacy in Chinese patients with advanced NSCLC. HER2 and HER3 expression does not provide any additional information for selecting patients most likely to benefit from gefitinib treatment.

Prospective phase II study of gefitinib in non-small cell lung cancer with epidermal growth factor receptor gene mutations

BACKGROUND

This study prospectively assessed the efficacy of gefitinib and the survival benefit for non-small cell lung cancer (NSCLC) patients with epidermal growth factor receptor (EGFR) mutations.

METHOD

Patients with either recurrent disease after undergoing surgery or advanced NSCLC disease (IIIB or IV) which demonstrated EGFR mutations were eligible for this study. EGFR mutations in exons 19-21 were examined. The patients with EGFR mutations were enrolled in this study after obtaining their informed consent a second time, and they were thereafter treated with gefitinib.

RESULTS

EGFR mutations were detected in 20 of 48 patients with NSCLC, and 19 patients were enrolled onto this study and treated with gefitinib. Seven patients had an exon 19 deletion, 10 had L858R, 1 had both, and 1 had an exon 19 deletion and G796A. The overall response rate was 63.2%, and the disease control rate was 89.5%. In patients with an exon 19 del and L858R, the response rates were 71.4% and 60.0%, respectively. The median progression-free survival time was 7.1 months, and the median survival time was 20.0 months. No life-threatening toxicity was observed. Four of five acquired resistant tumors showed an acquired T790M mutation.

CONCLUSIONS

EGFR mutations in exons 19 or 21 are considered to be a good predictor of the efficacy of gefitinib.

Non-small cell lung cancer-smokers or non-smokers, does it matter?

Besides epidermal growth factor receptor (EGFR) gene mutations, clinical factors such as smoking status have been identified as predictors for survival for NSCLC patients treated with EGFR-tyrosine kinase inhibitors (TKI). However, the biological screening for EGFR gene mutations is not routinely available everywhere. Therefore, the question arises if the decision to treat patients with EGFR-TKI should be based on clinical factors, and in particular smoking status, alone. We illustrate the difficulties faced by clinicians with the case of a 56-year-old man with stage IV lung adenocarcinoma and a smoking history of 30-pack-year. This patient received erlotinib first-line after its enrolment in a clinical trial. After 4 months, he presented with a dramatic clinical and radiological response. The biological analysis of the tumour revealed an EGFR exon 19 deletion. This report emphasizes that smoking status alone appears inappropriate in selecting patients for EGFR-TKI treatment. In addition, the relatively high number of (ex-)smokers retrieved from prospective studies on NSCLC patients with tumours showing an EGFR mutation should be emphasized, as it represents up to 30% of patients. Therefore, a biological rather than a clinical selection for patients' eligibility for EGFR-TKI appears mandatory.

Gefitinib in advanced non-small cell lung cancer: does it deserve a second chance?

There has been intense investigation into the epidermal growth factor receptor (EGFR) as a therapeutic target in the treatment of non-small cell lung cancer (NSCLC). Currently there are two EGFR tyrosine kinase inhibitors, erlotinib and gefitinib, approved for the treatment of advanced NSCLC. In a phase III trial (BR.21), treatment with erlotinib resulted in a statistically significant improvement in overall survival in patients who had experienced progression after one or two previous chemotherapy treatments in comparison with best supportive care (BSC). In contrast, in the Iressa Survival Evaluation in Lung Cancer (ISEL) trial, treatment with gefitinib did not result in a statistically significant improvement in overall survival time in comparison with BSC in patients who had received one or two previous chemotherapy treatments and were refractory to or intolerant of the previous chemotherapy. After the results of the ISEL trial, the U.S. Food and Drug Administration restricted the use of gefitinib, and gefitinib was effectively removed from routine clinical practice within the U.S. However, gefitinib was approved in other countries and clinical trials investigating gefitinib continued. Recently the Iressa Non-small cell lung cancer Trial Evaluating REsponse and Survival against Taxotere (INTEREST) trial met the primary endpoint of demonstrating noninferiority in terms of overall survival for gefitinib (250 mg daily) in comparison with docetaxel (75 mg/m(2) every 3 weeks). Patients treated with gefitinib experienced a lower rate of treatment-related toxicity and higher rate of improvement in quality of life. Results of recent gefitinib trials have been provocative, and suggest a role for gefitinib in the treatment of advanced NSCLC.

Lung cancer with epidermal growth factor receptor exon 20 mutations is associated with poor gefitinib treatment response

PURPOSE

Clinical reports about responsiveness to gefitinib treatment in patients of non-small cell lung cancer (NSCLC) with mutations in exon 20 of epidermal growth factor receptor (EGFR) are limited. To increase understanding of the influence of exon 20 mutations on NSCLC treatment with gefitinib, we investigated the clinical features of lung cancer in patients with exon 20 mutations and analyzed the gefitinib treatment response.

EXPERIMENTAL DESIGN

We surveyed the clinical data and mutational studies of NSCLC patients with EGFR exon 20 mutations in the National Taiwan University Hospital and reviewed the literature reports about EGFR exon 20 mutations and the gefitinib treatment response.

RESULTS

Twenty-three patients with mutations in exon 20 were identified. Nine (39%) had coexisting mutations in EGFR exons other than exon 20. Sixteen patients received gefitinib treatment, and a response was noted in 4 patients. The gefitinib response rate of NSCLC with exon 20 mutations was 25%, far lower than those with deletions in exon 19 and L858R mutations. Interestingly, different exon 20 mutations and coexisting mutations seemed to have a different influence on gefitinib response.

CONCLUSIONS

EGFR exon 20 mutations of NSCLC patients result in poorer responsiveness to gefitinib treatment, but variability exists between different individuals.

Detection of mutations in EGFR in circulating lung-cancer cells

BACKGROUND

The use of tyrosine kinase inhibitors to target the epidermal growth factor receptor gene (EGFR) in patients with non-small-cell lung cancer is effective but limited by the emergence of drug-resistance mutations. Molecular characterization of circulating tumor cells may provide a strategy for noninvasive serial monitoring of tumor genotypes during treatment.

METHODS

We captured highly purified circulating tumor cells from the blood of patients with non-small-cell lung cancer using a microfluidic device containing microposts coated with antibodies against epithelial cells. We performed EGFR mutational analysis on DNA recovered from circulating tumor cells using allele-specific polymerase-chain-reaction amplification and compared the results with those from concurrently isolated free plasma DNA and from the original tumor-biopsy specimens.

RESULTS

We isolated circulating tumor cells from 27 patients with metastatic non-small-cell lung cancer (median number, 74 cells per milliliter). We identified the expected EGFR activating mutation in circulating tumor cells from 11 of 12 patients (92%) and in matched free plasma DNA from 4 of 12 patients (33%) (P=0.009). We detected the T790M mutation, which confers drug resistance, in circulating tumor cells collected from patients with EGFR mutations who had received tyrosine kinase inhibitors. When T790M was detectable in pretreatment tumor-biopsy specimens, the presence of the mutation correlated with reduced progression-free survival (7.7 months vs. 16.5 months, P<0.001). Serial analysis of circulating tumor cells showed that a reduction in the number of captured cells was associated with a radiographic tumor response; an increase in the number of cells was associated with tumor progression, with the emergence of additional EGFR mutations in some cases.

CONCLUSIONS

Molecular analysis of circulating tumor cells from the blood of patients with lung cancer offers the possibility of monitoring changes in epithelial tumor genotypes during the course of treatment.

Current status of biomarkers in head and neck cancer

As our understanding of HNSCC increases so has biomarker development. HPV16 integration is a significant marker of favorable prognosis and response to therapy for HNSCC. EGFR-amplification and overexpression is a poor-prognostic indicator. For premalignant lesions, LOH of 3p&9p21 loci confers an elevated risk of malignant transformation. As molecular targets are identified, these will be candidates for biomarkers for detection, diagnosis, prognosis, and therapy. Validation of these biomarkers requires demonstration of independence of significance beyond known biomarkers.

Molecular predictors of EGFR-TKI sensitivity in advanced non-small cell lung cancer

The epidermal growth factor receptor (EGFR) is overexpressed in the majority of non-small cell lung cancers (NSCLC) and is a major target for new therapies. Specific EGFR tyrosine kinase inhibitors (TKIs) have been developed and used for the treatment of advanced NSCLC. The clinical response, however, varies dramatically among different patient cohorts. Females, East Asians, non-smokers, and patients with adenocarcinoma usually show higher response rates. Meanwhile, a number of biological factors are also associated with EGFR-TKIs responsiveness. In order to better understand the predictive value of these biomarkers and their significance in clinical application we prepared this brief review. Here we mainly focused on EGFR somatic mutations, MET amplification, K-ras mutations, EGFRvIII mutation, EGFR gene dosage and expression, HER2 gene dosage and expression, and Akt phosphorylation. We think EGFR somatic mutation probably is the most effective molecular predictor for EGFR-TKIs responsiveness and efficacy. Mutation screening test can provide the most direct and valuable guidance for clinicians to make decision on EGFR-TKIs therapy.

Specific EGFR mutations predict treatment outcome of stage IIIB/IV patients with chemotherapy-naive non-small-cell lung cancer receiving first-line gefitinib monotherapy

PURPOSE

To explore predictive factors for time to treatment failure (TTF) in chemotherapy-naive non-small-cell lung cancer (NSCLC) patients receiving gefitinib treatment.

PATIENTS AND METHODS

We designed a phase II study to test gefitinib antitumor efficacy in advanced-stage, chemotherapy-naive NSCLC patients. Patients were treated with gefitinib 250 mg/d. Tumor assessments were performed every 2 months. Responding or stable patients were treated until progression or unacceptable toxicity. All scans were reviewed independently. EGFR exons 18-21 sequence, K-ras exon 2 sequence, and MET gene copy numbers were examined in available samples. Clinical or molecular predictors of TTF were examined by multivariate analysis.

RESULTS

One hundred six patients were enrolled. Ninety patients had tumor samples for biomarker tests. Overall response rate was 50.9% (95% CI, 41.4% to 60.4%). Median TTF was 5.5 months, and median overall survival (OS) was 22.4 months. The response rate and median TTF of the patients with exon 19 deletion (n = 20) were 95.0% and 8.9 months, for exon 21 L858R mutation (n = 23) were 73.9% and 9.1 month, and for other types of EGFR mutations (N = 12) were 16.7% and 2.3 months, respectively. In multivariate analysis, the presence of EGFR deletion exon 19 or L858R EGFR mutations in adenocarcinoma patients predicted longer TTF. High copy number of MET seemed to correlate with shorter TTF in patients with gefitinib-sensitive activating EGFR mutations.

CONCLUSION

In this prospective study, EGFR exon 19 deletion or L858R mutations in adenocarcinoma were the best predictors for longer TTF in stage IIIB/IV chemotherapy-naive NSCLC patients receiving first-line gefitinib monotherapy.

Targeting growth factors in lung cancer

Lung cancer causes more deaths than any other malignancy in the developed world. Advances in surgical techniques and chemotherapy/radiotherapy regimes have produced only minimal improvements in long-term survival. New therapeutic interventions are urgently required. Research has indicated that growth factor signaling may be an important novel target in lung cancer therapy. Preclinical studies have demonstrated the role of extracellular growth factors in lung cancer cell proliferation, metastasis, and resistance to cytotoxic therapy, and have elucidated the key molecular components of growth factor-signaling cascades. This has enabled the development of selective growth factor inhibitors, which have been evaluated in clinical trials and are now an accepted component of advanced lung cancer treatment. Further research is underway to improve the efficacy of this growth factor-targeted therapy. This article will outline the important aspects of this translational research indicating the growth factor-signaling pathways identified in lung cancer, clinical trials of anti-growth factor therapy, and potential future research directions.

Structure and clinical relevance of the epidermal growth factor receptor in human cancer

PURPOSE

To review the recent advances in the atomic-level understanding of the epidermal growth factor receptor (EGFR) tyrosine kinase (TK). We aim to highlight the current and future importance of these studies for the understanding and treatment of malignancies where EGFR-TK is improperly activated.

METHODS

The analysis was conducted on published crystal structures deposited in the Protein Data Bank (www.pdb.org) using the program O.

RESULTS

In this review we emphasize how recent EGFR kinase domain crystal structures can explain the mechanisms of activation for L858R and other EGFR-TK mutations, and compare these distinct activating mechanisms with those recently described for the wild-type EGFR. We suggest an atomic-level mechanism for the poor efficacy of lapatinib against tumors with activating EGFR kinase domain point mutations compared with the efficacy of gefitinib and erlotinib, and demonstrate how structural insights help our understanding of acquired resistance to these agents. We also highlight how these new molecular-level structural data are expected to affect the development of EGFR-TK targeted small molecule kinase inhibitors.

CONCLUSION

There are now more crystal structures published for the EGFR-TK domain than for any other TK. This wealth of crystallographic information is beginning to describe the mechanisms by which proper regulation of EGFR-TK is lost in disease. These crystal structures are beginning to show how small molecules inhibit EGFR-TK activity and will aid development of EGFR-TK mutant targeted therapies.

Overview of chemoradiation clinical trials for locally advanced non-small cell lung cancer in Japan

The standard of care for unresectable stage III non-small cell lung cancer (NSCLC) is combined-modality therapy with both chemotherapy and thoracic radiation therapy (TRT). A phase III trial by the West Japan Lung Cancer Group revealed that the combination of mitomycin, vindesine, and cisplatin (MVP) with concurrent TRT yielded a median survival time of 16.6 months and a 5-year survival rate of 16% in patients with unresectable stage III NSCLC. Although evidence indicates that concurrent chemotherapy and TRT (chemoradiation) increases survival to a moderately greater extent than sequential therapeutic approaches, the optimal strategies for such concurrent treatment remain to be defined, and differ between full-dose systemic and low-dose radio-enhancing protocols. Two phase III trials have been initiated in Japan to address these issues and they have recently reported preliminary data. Early results of the Okayama Lung Cancer Study Group (OLCSG) trial, comparing chemoradiation based on divided docetaxel and cisplatin chemotherapy with MVP-based chemoradiation, have been reported. The West Japan Oncology Group (WJOG) is comparing the efficacy and toxicity of TRT and concurrent chemotherapy with either carboplatin-paclitaxel or carboplatin-irinotecan, followed by full-dose consolidation chemotherapy, with the efficacy and toxicity of MVP-based chemoradiation. Several phase I/II studies to test the optimal use of new agents such as S-1 (an oral anticancer drug combining tegafur, 5-chloro-2, 4-dihydroxypyridine, and potassium oxonate) and gefitinib (an inhibitor of the tyrosine kinase activity of the epidermal growth factor receptor) are also ongoing. In addition, radiation dose intensification with three-dimensional planning approaches is currently under evaluation. A phase I clinical trial by WJOG to establish, prospectively, the maximum tolerated dose of three-dimensional hyperfractionated radiotherapy with concurrent weekly chemotherapy (carboplatin-paclitaxel) is thus currently under way. This overview of ongoing trials highlights new directions in the treatment of locally advanced NSCLC.