Setting the benchmark for tailoring treatment with EGFR tyrosine kinase inhibitors

Drug resistance analysis of gefitinib-targeted therapy in non-small cell lung cancer

The aim of the study was to examine the drug resistance analysis of gefitinib-targeted therapy in non-small cell lung cancer (NSCLC). In total, 156 NSCLC patients without surgical treatment were selected, including 117 cases of adenocarcinoma (75%), to receive single gefitinib 0.25 g/day or combined with platinum chemotherapy. Computed tomography was used to evaluate tumor growth for the response and non-response groups. The chemotherapy regimen was changed or combined with radiotherapy in the non-response group. Tumor progression or metastasis in the response group was considered as the generation of drug resistance. The chemotherapy regimen was altered in the response group. Eleven cases had tumor response in the non-response group after the chemotherapy regimen was adjusted (20%), 33 cases had complete response (CR) (32.7%), 44 cases had partial response (PR) (43.6%), and 24 cases had stable disease (SD) (23.8%) in the response group. The drug resistance rates of CR, PR, and SD showed no significant difference (P>0.05). However, the drug-resistant time of CR was significantly delayed and the difference was statistically significant (P<0.05). The response rates of CR, PR, and SD patients regaining the response rate showed no statistical significance after the chemotherapy regimen was adjusted, and the difference was not statistically significant (P>0.05). In conclusion, gefitinib-targeted therapy in NSCLC showed certain drug resistance, which may not be related to the response.

Role of gefitinib in the targeted treatment of non-small-cell lung cancer in Chinese patients

Non-small-cell lung cancer (NSCLC) is the most common type of lung cancer. Conventional treatment options have limited efficacy because most cases are in the advanced stage at the time of diagnosis. In recent years, gefitinib, an epidermal growth factor receptor tyrosine kinase inhibitor, has shown its good antitumor activities in treating NSCLC in a number of studies. This paper reviews its role in the targeted treatment of NSCLC in Chinese patients.

A view on EGFR-targeted therapies from the oncogene-addiction perspective

Tumor cell growth and survival can often be impaired by inactivating a single oncogen– a phenomenon that has been called as “oncogene addiction.” It is in such scenarios that molecular targeted therapies may succeed. among known oncogenes, the epidermal growth factor receptor (EGFR) has become the target of different cancer therapies. So far, however, the clinical benefit from EGFR-targeted therapies has been rather limited. a critical review of the large amount of clinical data obtained with anti-EGFR agents, carried out from the perspective of the oncogene addiction concept, may help to understand the causes of the unsatisfactory results. In this article we intend to do such an exercise taking as basis for the analysis a few case studies of anti-EGFR agents that are currently in the clinic. There, the “EGFR addiction” phenomenon becomes apparent in high-responder patients. We further discuss how the concept of oncogene addiction needs to be interpreted on the light of emerging experimental evidences and ideas; in particular, that EGFR addiction may reflect the interconnection of several cellular pathways. In this regard we set forth several hypotheses; namely, that requirement of higher glucose uptake by hypoxic tumor cells may reinforce EGFR addiction; and that chronic use of EGFR-targeted antibodies in EGFR-addicted tumors would induce stable disease by reversing the malignant phenotype of cancer stem cells and also by sustaining an anti-tumor T cell response. Finally, we discuss possible reasons for the failure of certain combinatorial therapies involving anti-EGFR agents, arguing that some of these agents might produce either a negative or a positive trans-modulation effect on other oncogenes. It becomes evident that we need operational definitions of EGFR addiction in order to determine which patient populations may benefit from treatment with anti-EGFR drugs, and to improve the design of these therapies.

Recursive partitioning analysis classification and graded prognostic assessment for non-small cell lung cancer patients with brain metastasis: a retrospective cohort study

OBJECTIVE

To assess prognostic factors and validate the effectiveness of recursive partitioning analysis (RPA) classes and graded prognostic assessment (GPA) in 290 non-small cell lung cancer (NSCLC) patients with brain metastasis (BM).

METHODS

From Jan 2008 to Dec 2009, the clinical data of 290 NSCLC cases with BM treated with multiple modalities including brain irradiation, systemic chemotherapy and tyrosine kinase inhibitors (TKIs) in two institutes were analyzed. Survival was estimated by Kaplan-Meier method. The differences of survival rates in subgroups were assayed using log-rank test. Multivariate Cox's regression method was used to analyze the impact of prognostic factors on survival. Two prognostic indexes models (RPA and GPA) were validated respectively.

RESULTS

All patients were followed up for 1-44 months, the median survival time after brain irradiation and its corresponding 95% confidence interval (95% CI) was 14 (12.3-15.8) months. 1-, 2- and 3-year survival rates in the whole group were 56.0%, 28.3%, and 12.0%, respectively. The survival curves of subgroups, stratified by both RPA and GPA, were significantly different (P<0.001). In the multivariate analysis as RPA and GPA entered Cox's regression model, Karnofsky performance status (KPS) ≥ 70, adenocarcinoma subtype, longer administration of TKIs remained their prognostic significance, RPA classes and GPA also appeared in the prognostic model.

CONCLUSION

KPS ≥70, adenocarcinoma subtype, longer treatment of molecular targeted drug, and RPA classes and GPA are the independent prognostic factors affecting the survival rates of NSCLC patients with BM.

Integrin beta1 over-expression associates with resistance to tyrosine kinase inhibitor gefitinib in non-small cell lung cancer

The epidermal growth factor receptor tyrosine kinase inhibitors (EGFR TKIs) such as gefitinib and erlotinib have been widely used in treating patients with advanced non-small cell lung cancer (NSCLC). However, acquired resistance to EGFR TKI almost occurs in every patient eventually. To identify its potential mechanism, we established a human NSCLC cell line PC9/AB2 which was 576-fold decrease in gefitinib sensitivity compared with its parental PC9 cell lines. No EGFR-T790M mutation or abnormal expression of c-Met protein was found in PC9/AB2 cells. Over-expression of integrin β1 was found, accompanied with increase of the cells' adhesion and migration. To further confirm the role of integrin β1 in gefitinib acquired resistance, we transferred its siRNA-expressing plasmid and its whole cDNA expressing plasmid into PC9/AB2 and into PC9 cells, respectively. The sensitivity of NSCLC cells to gefitinib was negatively correlated with integrin β1 expression levels. All these data suggest that up-regulation of integrin β1 might be an important factor for gefitinib resistance in NSCLC cell line PC9/AB2.

Randomized clinical trials with biomarkers: design issues

Clinical biomarker tests that aid in making treatment decisions will play an important role in achieving personalized medicine for cancer patients. Definitive evaluation of the clinical utility of these biomarkers requires conducting large randomized clinical trials (RCTs). Efficient RCT design is therefore crucial for timely introduction of these medical advances into clinical practice, and a variety of designs have been proposed for this purpose. To guide design and interpretation of RCTs evaluating biomarkers, we present an in-depth comparison of advantages and disadvantages of the commonly used designs. Key aspects of the discussion include efficiency comparisons and special interim monitoring issues that arise because of the complexity of these RCTs. Important ongoing and completed trials are used as examples. We conclude that, in most settings, randomized biomarker-stratified designs (ie, designs that use the biomarker to guide analysis but not treatment assignment) should be used to obtain a rigorous assessment of biomarker clinical utility.

Gene expression profiling and non-small-cell lung cancer: where are we now?

Despite new developments in molecular techniques and better knowledge on lung cancer tumor biology, many genetic alterations associated with the development and progression of lung carcinogenesis still remain unclear. Although the development of targeted agents has improved response rates and survival, lung cancer has a very high mortality rate, even for early stages. Thus, there is a greater need for other mechanisms or technologies that may help us diagnose, predict, and treat patients with lung cancer in a more effective way. One of these technologies has been the use of genomics. Some of the available genomic technologies include single-nucleotide polymorphism analysis, high-throughput capillary sequencing, serial analysis of gene expression, and gene expression arrays. DNA microarray analysis is capable of discovering changes in DNA expression within the neoplastic tumor. Thus, gene expression array could help us to decipher the complexity and interaction of different oncogenic pathways and, hence, could contribute to the selection of better targeted agents on an individual basis rather than a general and nonspecific approach as it has been done for many decades. Several studies initiated a few years ago have started to produce fruitful results. Herein, we review the role of gene expression profiling in lung cancer as a diagnostic tool, predictive and prognostic biomarker, and its potential use for a "personalized" medicine in the years to come.

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.

Epidermal growth factor receptor-related tumor markers and clinical outcomes with erlotinib in non-small cell lung cancer: an analysis of patients from german centers in the TRUST study

INTRODUCTION

Relationships between clinical outcomes and epidermal growth factor receptor (EGFR)-related tumor markers were investigated in patients with advanced non-small cell lung cancer.

METHODS

Patients with stage IIIB/IV non-small cell lung cancer (0-2 prior regimens) received erlotinib (150 mg PO per day). Response and survival were evaluated, and tumor samples were assessed by immunohistochemistry (EGFR, phosphorylated mitogen-activated protein kinase, and phosphorylated AKT protein expression), fluorescence in situ hybridization (FISH; EGFR gene copy number), and DNA sequencing (EGFR, KRAS gene mutations).

RESULTS

Among 311 patients, 8% had a complete/partial response; the disease control rate was 66%. Median Overall survival (OS) was 6.1 months; 1-year survival rate was 27.2%. Two of 4 patients with EGFR mutations had tumor responses, versus 2/68 with wild-type EGFR (p = 0.014). Progression-free survival (PFS) (HR = 0.31) and OS (HR = 0.33) were significantly prolonged in patients with EGFR mutations. Response rate was significantly higher in patients with EGFR FISH-positive (17%) than FISH-negative tumors (6%), and both PFS (HR = 0.58) and OS (HR = 0.63) significantly favored patients with EGFR FISH-positive tumors; median OS was 8.6 months in the EGFR FISH-positive group. None of 17 patients with a KRAS mutation had a tumor response, but the impact of KRAS mutation status on survival outcomes was of borderline statistical significance. Neither phosphorylated mitogen-activated protein kinase nor phosphorylated AKT immunohistochemistry status had a significant effect on PFS and OS with erlotinib.

CONCLUSIONS

The presence of EGFR mutations and EGFR FISH-positive tumors may predispose patients to achieving better outcomes on erlotinib, but may have a beneficial impact on prognosis (irrespective of treatment). Prospective, placebo-controlled studies are needed to determine the predictive value of the putative biomarkers.

A sensitive method for detecting EGFR mutations in non-small cell lung cancer samples with few tumor cells

BACKGROUND

Detection of epidermal growth factor receptor (EGFR) mutations in advanced non-small cell lung cancer (NSCLC) patients has relied on DNA purification from biopsies, amplification, and sequencing. However, the number of tumor cells in a sample is often insufficient for EGFR assessment.

METHODS

We prospectively screened 1380 NSCLC patients for EGFR mutations but found that 268 were not evaluable because of insufficient tumor tissue. We therefore developed and validated a method of detecting EGFR mutations in these samples. Tumor cells were microdissected into polymerase chain reaction buffer and amplified. EGFR mutations were detected by length analysis of fluorescently labeled polymerase chain reaction products and TaqMan assay.

RESULTS

We determined EGFR status in 217 (81%) of the 268 primary NSCLC samples not evaluable in our original study-fresh and paraffin-embedded with less than 150 cells. Exon 19 deletions were detected in 11.5% of patients and exon 21 L858R mutations in 5.5%. In addition, the exon 20 T790M mutation was detected in 6 of 15 (40%) patients at the time of progression to erlotinib. The primary, sensitive mutation was present in all tumor cells, whereas the T790M mutation was absent in some groups.

CONCLUSIONS

The method presented here eliminates the need for DNA purification and allows for detection of EGFR mutations in samples containing as few as eight cancer cells.

Therapeutic Strategy for Treatment of Metastatic Non-Small Cell Lung Cancer

Objective:

To review the current practices for metastatic non–small cell lung cancer (NSCLC) management and highlight the latest progress.

Data Sources:

A literature review using HighWire Press (1960–May 2008) was conducted using the following key words: non–small cell lung cancer, chemotherapy. supportive care, therapeutic strategy, quality of life (QOL), and targeted therapies.

Study Selection and Data Extraction:

Review articles, clinical trials, and case reports, as well as the references of those articles, were reviewed. Statistical significance and number of patients included in the studies were some of the aspects that were considered seriously. Response rates, overall survival, and progression-free survival were the major data considered.

Data Synthesis:

The therapeutic management of metastatic NSCLC has undergone a profound evolution over the past 10 years. The positive impact of chemotherapy on survival compared with supportive care atone has been demonstrated by several meta-analyses. The development of third-generation agents with better efficacy/toxicity ratios, such as vinorelbine, paclitaxel, docetaxel, gemcitabine, and pemetrexed, has led to improved therapeutic management of NSCLC, especially when tailored to patients' comorbidities and performance status. First-line platinum-based combinations remain the standard of care, with median survival 8 months and 1-year survival 35%, but no particular combination has yet shown superiority. First-line platinum regimens in combination with bevacizumab, a targeted inhibitor of vascular endothelial growth factor, have further improved NSCLC median survival. Moreover, second- and third-line treatments have evolved. The addition of small-molecule epidermal growth factor inhibitors and other targeted therapies has modified the pattern of NSCLC treatment. Specific management of the elderly and patients with poor performance status should be applied.

Conclusions:

Although there has been progress in the treatment of NSCLC, the gain in terms of clinical response and survival is still modest. Maintaining QOL and tailoring therapy for patients based on age, performance status, comorbidities, and toxicities, remain the first priority for clinicians.

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.

Erlotinib therapy in a patient with non-small-cell lung cancer and brain metastases

Brain metastases are a common occurrence and a major cause of mortality in non-small-cell lung cancer, with few systemic treatment options. Although targeting epidermal growth factor receptor-associated tyrosine kinase with erlotinib and gefitinib results in durable responses in some patients, the activity of these drugs against brain metastases has been poorly documented. In particular, few reports have so far reported the activity of erlotinib in this setting. Here we report the case of a male Italian smoker with an adeno-carcinoma of the lung whose lung cancer and brain metastases have both responded to erlotinib.

Advances in targeting the Ras/Raf/MEK/Erk mitogen-activated protein kinase cascade with MEK inhibitors for cancer therapy

The identification of intracellular signaling cascades important for the growth and survival of cancer cells has led to the development of targeted cancer therapeutics aimed at blocking these signals. The mitogen-activated protein kinase (MAPK) pathway has a well-defined role in cancer biology and has been an important target in the development of targeted therapies. Recently, several small-molecule inhibitors of MAPK/extracellular signal-regulated kinase kinase (MEK), a key intermediary of MAPK signaling, have been developed and are currently being tested in clinical trials. Herein, we review the MAPK pathway, the development of small-molecule MEK inhibitors, and the results obtained to date with MEK inhibitors in human cancer trials.

Integrating pharmacogenomics into oncology clinical practice

Oncology pharmacogenomics has seen a great deal of progress in the past 10 years. The release of the Human Genome Project data and the availability of fast, affordable genotyping platforms has allowed the field to expand and has provided invaluable data for pharmacogenomics research. The introduction of US FDA-approved targeted therapy (trastuzumab), package insert changes (irinotecan and tamoxifen) and the initiation of a genotype-guided clinical trial for cancer therapy (TYMS TSER in rectal cancer), along with panels of DNA and expression markers (Roche AmpliChip(®) and Oncotype Dx™ panel) are paving the way towards the integration of pharmacogenomics into clinical practice.

Resistance to an irreversible epidermal growth factor receptor (EGFR) inhibitor in EGFR-mutant lung cancer reveals novel treatment strategies

Patients with epidermal growth factor receptor (EGFR)-mutant non-small cell lung cancer derive significant clinical benefit from treatment with the EGFR tyrosine kinase inhibitors gefitinib and erlotinib. Secondary EGFR mutations such as EGFR T790M commonly lead to resistance to these agents, limiting their long-term efficacy. Irreversible EGFR inhibitors such as CL-387,785 can overcome resistance and are in clinical development, yet acquired resistance against these agents is anticipated. We carried out a cell-based, in vitro random mutagenesis screen to identify EGFR mutations that confer resistance to CL-387,785 using T790M-mutant H1975 lung adenocarcinoma cells. Mutations at several residues occurred repeatedly leading to functional resistance to CL-387,785. These variants showed uninhibited cell growth, reduced apoptosis, and persistent EGFR activation in the presence of CL-387,785 as compared with parental H1975 cells, thus confirming their role in resistance. A screen of alternative agents showed that both an alternative EGFR inhibitor and a cyclin-dependent kinase 4 inhibitor led to significant inhibition of cell growth of the resistant mutants, suggestive of potential alternative treatment strategies. These results identify novel mutations mediating resistance to irreversible EGFR inhibitors and reveal alternative strategies to overcome or prevent the development of resistance in EGFR-mutant non-small cell lung cancers.