Prospective phase II study of gefitinib for chemotherapy-naive patients with advanced non-small-cell lung cancer with epidermal growth factor receptor gene mutations

Epidermal growth factor receptor in relation to tumor development: EGFR-targeted anticancer therapy

The discovery that signaling by the epidermal growth factor receptor (EGFR) plays a key role in tumorigenesis prompted efforts to target this receptor in anticancer therapy. Two different types of EGFR-targeted therapeutic agents were subsequently developed: mAbs, such as cetuximab and panitumumab, which target the extracellular domain of the receptor, thereby inhibiting ligand-dependent EGFR signal transduction; and small-molecule tyrosine kinase inhibitors, such as gefitinib and erlotinib, which target the intracellular tyrosine kinase domain of the EGFR. Furthermore, recent clinical and laboratory studies have identified molecular markers that have the potential to improve the clinical effectiveness of EGFR-targeted therapies. This minireview summarizes the emerging role of molecular profiling in guiding the clinical use of anti-EGFR therapeutic agents.

Chemotherapy for lung cancer: the state of the art in 2009

Lung cancer remains the most common cause of cancer-related death among men and women worldwide. Incremental and significant advances in available systemic treatments, however, have taken place in the last decade to provide improved survival rates and better palliation for patients with non-small-cell and small-cell lung cancer. Superior imaging techniques have enabled the detection of early-stage disease and adjuvant chemotherapy has earned a place for select patients following resection of their tumors. Perhaps the largest growth has been in the area of advanced non-small-cell lung cancer, in which multiple new combination and single-agent systemic therapies have become standard where previously only 'best supportive care' was thought appropriate. In concert with broader applicability of chemotherapy, translational studies have provided the rationale for using molecular markers to identify the patients most likely to benefit from biological and targeted therapies. This review will discuss the current role of chemotherapy in both early and advanced non-small-cell and small-cell lung cancer. Novel targeted systemic therapies and the appropriate selection of treatments for patients based on their tumors' molecular phenotypes and histologies will also be reviewed.

American Society of Clinical Oncology Clinical Practice Guideline update on chemotherapy for stage IV non-small-cell lung cancer

The purpose of this article is to provide updated recommendations for the treatment of patients with stage IV non-small-cell lung cancer. A literature search identified relevant randomized trials published since 2002. The scope of the guideline was narrowed to chemotherapy and biologic therapy. An Update Committee reviewed the literature and made updated recommendations. One hundred sixty-two publications met the inclusion criteria. Recommendations were based on treatment strategies that improve overall survival. Treatments that improve only progression-free survival prompted scrutiny of toxicity and quality of life. For first-line therapy in patients with performance status of 0 or 1, a platinum-based two-drug combination of cytotoxic drugs is recommended. Nonplatinum cytotoxic doublets are acceptable for patients with contraindications to platinum therapy. For patients with performance status of 2, a single cytotoxic drug is sufficient. Stop first-line cytotoxic chemotherapy at disease progression or after four cycles in patients who are not responding to treatment. Stop two-drug cytotoxic chemotherapy at six cycles even in patients who are responding to therapy. The first-line use of gefitinib may be recommended for patients with known epidermal growth factor receptor (EGFR) mutation; for negative or unknown EGFR mutation status, cytotoxic chemotherapy is preferred. Bevacizumab is recommended with carboplatin-paclitaxel, except for patients with certain clinical characteristics. Cetuximab is recommended with cisplatin-vinorelbine for patients with EGFR-positive tumors by immunohistochemistry. Docetaxel, erlotinib, gefitinib, or pemetrexed is recommended as second-line therapy. Erlotinib is recommended as third-line therapy for patients who have not received prior erlotinib or gefitinib. Data are insufficient to recommend the routine third-line use of cytotoxic drugs. Data are insufficient to recommend routine use of molecular markers to select chemotherapy.

Molecular analysis-based treatment strategies for the management of non-small cell lung cancer

Even with the introduction of targeted agents and the establishment of multiple lines of therapy, the median survival for patients with advanced non-small cell lung cancer (NSCLC) does not considerably extend beyond 1 year. Emerging research suggests that clinical characteristics alone are insufficient for selecting patients for therapies that may confer significant survival benefit. The discovery of predictive and prognostic molecular markers such as gene mutations in EGFR and KRAS as well as high tumor expression levels of DNA repair pathway components ribonucleotide reductase subunit 1 and excision repair cross-complementing group 1 has sparked an interest in the development of individualized therapy as a strategy for increasing survival in patients with NSCLC. Techniques to analyze molecular biomarkers, such as immunohistochemistry, fluorescence in situ hybridization, polymerase chain reaction, and, more recently, gene microarray techniques, are being investigated for their potential to accurately predict an individual patient's response to therapy. Many prospective trials are still needed to clarify and confirm the utility of molecular biomarkers for guiding treatment selection, and continued participation in clinical trials is critical for the development of tools to provide customized treatment plans for patients with NSCLC.

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.

Crosstalk to stromal fibroblasts induces resistance of lung cancer to epidermal growth factor receptor tyrosine kinase inhibitors

PURPOSE

Lung cancers with epidermal growth factor receptor (EGFR)-activating mutations show good clinical response to gefitinib and erlotinib, selective tyrosine kinase inhibitors (TKI) to EGFR, but these tumors invariably develop drug resistance. Host stromal cells have been found to have a considerable effect on the behavior of cancer cells. Little is known, however, about the role of host cells on the sensitivity of cancer cells to receptor TKIs. We have therefore assessed the effect of crosstalk between stromal cells and lung cancer cells harboring EGFR mutations on susceptibility to EGFR-TKIs.

EXPERIMENTAL DESIGN

We evaluated the gefitinib sensitivity of lung cancer cells with EGFR-activating mutations, PC-9 and HCC827, when cocultured with fibroblasts and coinjected into severe combined immunodeficient mice. We also examined the effect of lung cancer cells to fibroblast recruitment.

RESULTS

Both human fibroblast cell lines and primary cultured fibroblasts produced various levels of hepatocyte growth factor (HGF). Lung cancer cells markedly recruited fibroblasts. The lung cancer cells became resistant to EGFR-TKIs when cocultured in vitro with HGF-producing fibroblasts and coinjected into severe combined immunodeficient mice. Importantly, combined use of gefitinib plus anti-HGF antibody or the HGF antagonist, NK4, successfully overcame the fibroblast-induced EGFR-TKI resistance both in vitro and in vivo. Colocalization of fibroblasts and HGF was detected in both xenograft tumors in mouse model and lung cancer patient specimens.

CONCLUSIONS

These findings indicate that crosstalk to stromal fibroblasts plays a critical role in lung cancer resistance to EGFR-TKIs and may be an ideal therapeutic target in lung cancer with EGFR-activating mutations.

Gefitinib or carboplatin-paclitaxel in pulmonary adenocarcinoma

BACKGROUND

Previous, uncontrolled studies have suggested that first-line treatment with gefitinib would be efficacious in selected patients with non-small-cell lung cancer.

METHODS

In this phase 3, open-label study, we randomly assigned previously untreated patients in East Asia who had advanced pulmonary adenocarcinoma and who were nonsmokers or former light smokers to receive gefitinib (250 mg per day) (609 patients) or carboplatin (at a dose calculated to produce an area under the curve of 5 or 6 mg per milliliter per minute) plus paclitaxel (200 mg per square meter of body-surface area) (608 patients). The primary end point was progression-free survival.

RESULTS

The 12-month rates of progression-free survival were 24.9% with gefitinib and 6.7% with carboplatin-paclitaxel. The study met its primary objective of showing the noninferiority of gefitinib and also showed its superiority, as compared with carboplatin-paclitaxel, with respect to progression-free survival in the intention-to-treat population (hazard ratio for progression or death, 0.74; 95% confidence interval [CI], 0.65 to 0.85; P<0.001). In the subgroup of 261 patients who were positive for the epidermal growth factor receptor gene (EGFR) mutation, progression-free survival was significantly longer among those who received gefitinib than among those who received carboplatin-paclitaxel (hazard ratio for progression or death, 0.48; 95% CI, 0.36 to 0.64; P<0.001), whereas in the subgroup of 176 patients who were negative for the mutation, progression-free survival was significantly longer among those who received carboplatin-paclitaxel (hazard ratio for progression or death with gefitinib, 2.85; 95% CI, 2.05 to 3.98; P<0.001). The most common adverse events were rash or acne (in 66.2% of patients) and diarrhea (46.6%) in the gefitinib group and neurotoxic effects (69.9%), neutropenia (67.1%), and alopecia (58.4%) in the carboplatin-paclitaxel group.

CONCLUSIONS

Gefitinib is superior to carboplatin-paclitaxel as an initial treatment for pulmonary adenocarcinoma among nonsmokers or former light smokers in East Asia. The presence in the tumor of a mutation of the EGFR gene is a strong predictor of a better outcome with gefitinib. (ClinicalTrials.gov number, NCT00322452.)

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.

Impact of epidermal growth factor receptor and KRAS mutations on clinical outcomes in previously untreated non-small cell lung cancer patients: results of an online tumor registry of clinical trials

PURPOSE

The impact of epidermal growth factor receptor (EGFR) and KRAS genotypes on outcomes with erlotinib or gefitinib therapy continues to be debated. This study combines patient data from five trials in predominantly Western populations to assess the impact of EGFR and KRAS mutations on first-line therapy with an EGFR-tyrosine kinase inhibitor (TKI) and compare clinical versus molecular predictors of sensitivity.

EXPERIMENTAL DESIGN

Chemotherapy-naïve patients with advanced non-small cell lung cancer and known EGFR mutation status treated with erlotinib or gefitinib monotherapy as part of a clinical trial were eligible for inclusion. Patients received daily erlotinib (150 mg) or gefitinib (250 mg) until disease progression or unacceptable toxicity. Data were collected in a password-protected web database. Clinical outcomes were analyzed to look for differences based on EGFR and KRAS genotypes, as well as clinical characteristics.

RESULTS

Patients (223) from five clinical trials were included. Sensitizing EGFR mutations were associated with a 67% response rate, time to progression (TTP) of 11.8 months, and overall survival of 23.9 months. Exon 19 deletions were associated with longer median TTP and overall survival compared with L858R mutations. Wild-type EGFR was associated with poorer outcomes (response rate, 3%; TTP, 3.2 months) irrespective of KRAS status. No difference in outcome was seen between patients harboring KRAS transition versus transversion mutations. EGFR genotype was more effective than clinical characteristics at selecting appropriate patients for consideration of first-line therapy with an EGFR-TKI.

CONCLUSION

EGFR mutation status is associated with sensitivity to treatment with an EGFR-TKI in patients with advanced non-small cell lung cancer. Patients harboring sensitizing EGFR mutations should be considered for first-line erlotinib or gefitinib.

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.

Reasons for response differences seen in the V15-32, INTEREST and IPASS trials

The first phase III study to assess the effect of gefitinib and docetaxel on the survival of Japanese patients with non-small-cell lung cancer who received previous treatment with platinum doublets, the V15-32 trial, did not establish noninferiority of gefitinib over docetaxel in terms of the effect on overall survival, despite the results showing a twofold higher response rate to gefitinib. The overall survival favored docetaxel for the first 18 months and gefitinib thereafter. The INTEREST trial, which compared docetaxel and gefitinib, demonstrated noninferiority of gefitinib, and the survival curves were completely superimposed. In this trial, patients had been recruited from 24 countries from Europe, Asia, and North and South America. Results of the IPASS trial showed superior progression-free survival for gefitinib compared with the combination of carboplatin and paclitaxel as first-line treatment in Asian patients who were nonsmokers and had adenocarcinoma histology. In this Review, we discuss the reasons for the differences in the effects of molecular-targeted drugs and cytotoxic antineoplastic agents observed in these trials. We also highlight the magnitude of the antitumor activity of these two different categories of drugs, and discuss how this could affect future clinical trial design and analysis.

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.

Functional analysis of epidermal growth factor receptor (EGFR) mutations and potential implications for EGFR targeted therapy

PURPOSE

Epidermal growth factor receptor (EGFR) mutations in non-small cell lung cancer (NSCLC) might be predictive for clinical response to EGFR inhibitor treatment. However, retrospective analyses of EGFR mutations in clinical trials have shown inconclusive results and the effect of EGFR sequencing in NSCLC is still controversial. Because the vast majority of EGFR mutations described have not been functionally characterized, simple correlation of mutational status and treatment response may not provide reliable information about the predictive value of EGFR mutations. Thus, we aimed to characterize a comprehensive panel of clinically observed EGFR mutations.

EXPERIMENTAL DESIGN AND RESULTS

A panel of 30 EGFR mutations was cloned and characterized for kinase activity and the ability to confer growth factor independence. Interestingly, 4 of 30 EGFR mutations showed no kinase activity even after ligand stimulation and were not able to confer growth factor independence. Ba/F3 cells expressing activating EGFR mutants were then used to test the efficacy of EGFR inhibitors in a cell proliferation assay. IC(50) values were calculated for gefitinib, erlotinib, and AEE788. We show that the sensitivity of EGFR mutations toward different inhibitors varies significantly, thus establishing a comprehensive sensitivity profile for each inhibitor.

CONCLUSIONS

EGFR mutations identified in NSCLC patients display distinct biological features. The variability in kinase activity, transforming potential, and sensitivity to EGFR inhibitors has to be considered in clinical studies aiming to correlate mutational status and drug response. The identification of comprehensive drug resistance profiles opens the opportunity to test alternative EGFR inhibitors in vitro.

Gefitinib in the treatment of advanced non-small-cell lung cancer

Most patients with non-small-cell lung cancer (NSCLC) present with advanced disease and their long-term prognosis remains poor, even after platinum-based chemotherapy. EGF receptor (EGFR)-targeted therapies, such as gefitinib, have been subject to comprehensive clinical development. Several Phase II and III trials have evaluated the clinical efficacy of gefitinib as monotherapy in pretreated patients with advanced NSCLC, as well as both monotherapy and combined with chemotherapy in chemo-naive patients. A Phase III trial in heavily pretreated advanced NSCLC patients, 90% of whom were refractory, demonstrated some improvement in survival with gefitinib compared with placebo; however, the difference was not statistically significant in the overall population. A second large Phase III trial in patients with pretreated advanced NSCLC (INTEREST) demonstrated the noninferiority of gefitinib in comparison with docetaxel for overall survival together with an improved quality of life and tolerability profiles. As a result, gefitinib is expected to have a large impact in the management of pretreated patients with NSCLC.

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.

Effects of vandetanib on lung adenocarcinoma cells harboring epidermal growth factor receptor T790M mutation in vivo

Vandetanib is a novel multitarget tyrosine kinase inhibitor (TKI) that inhibits vascular endothelial growth factor receptor-2 (VEGFR-2), with additional inhibition of epidermal growth factor receptor (EGFR) and rearranged during transfection receptor signaling, which has shown promising results in clinical trials for advanced non-small cell lung cancer. However, the mechanisms of acquired resistance to vandetanib remain unclear. Therefore, we established in vitro vandetanib-resistant PC-9/VanR cells from PC-9, a vandetanib-sensitive lung adenocarcinoma cell line, by chronic exposure to this agent. PC-9/VanR cells were 50-fold more resistant to vandetanib than PC-9 cells in vitro. Compared with PC-9 cells, PC-9/VanR cells showed emergence of an EGFR T790M mutation, moderately elevated MET amplification, and similar VEGFR-2 inhibition by vandetanib. Note that phospho-MET in PC-9/VanR was suppressed following EGFR inhibition by an irreversible EGFR-TKI, indicating that MET signaling of PC-9/VanR was dependent on EGFR signaling and that MET amplification was not the primary mechanism of resistance to vandetanib. In contrast to the in vitro experiment, vandetanib effectively inhibited the growth of PC-9/VanR tumors in an in vivo xenograft model through the antiangiogenesis effects of VEGFR-2 inhibition. In conclusion, the multitarget TKI vandetanib induced or selected for the EGFR T790M mutation as observed previously with highly selective EGFR-TKIs. However, vandetanib retained significant efficacy in vivo against xenografts harboring the T790M mutation, providing a strong scientific rationale for investigating vandetanib in clinical settings where acquired resistance through emergence of EGFR T790M mutations limits the effectiveness of highly selective EGFR-TKIs.

Brain metastases: current management and new developments

PURPOSE OF REVIEW

To review the state-of-the-art and new developments in the management of patients with brain metastases.

RECENT FINDINGS

Treatment decisions are based on prognostic factors to maximize neurologic function and survival, while avoiding unnecessary therapies. Whole-brain radiotherapy (WBRT) is the treatment of choice for patients with unfavorable prognostic factors. Stereotactic radiosurgery (SRS) or surgery is indicated for patients with favorable prognostic factors and limited brain disease. In single brain metastasis, the addition of either stereotactic radiosurgery or surgery to WBRT improves survival. The omission of WBRT after surgery or radiosurgery results in a worse local and distant control, though it does not affect survival. The incidence of neurocognitive deficits in long-term survivors after WBRT remains to be defined. New approaches to avoid cognitive deficits following WBRT are being investigated. The role of chemotherapy is limited. Molecularly targeted therapies are increasingly employed. Prophylaxis with WBRT is the standard in small-cell lung cancer.

SUMMARY

Many questions need future trials: the usefulness of new radiosensitizers; the role of local treatments after surgery; and the impact of molecularly targeted therapies on subgroups of patients with specific molecular profiles. Quality of life and cognitive functions are recognized as major endpoints in clinical trials.

PET monitoring of therapy response in head and neck squamous cell carcinoma

In the Western world, more than 90% of head and neck cancers are head and neck squamous cell carcinomas (HNSCCs). The most appropriate treatment approach for HNSCC varies with the disease stage and disease site in the head and neck. Concurrent chemoradiotherapy has become a widely used means for the definitive treatment of locoregionally advanced HNSCC. Although this multimodality treatment provides higher response rates than radiotherapy alone, the detection of residual viable tumor after the end of therapy remains an important issue and is one of the major applications of (18)F-FDG PET. Studies have shown that negative (18)F-FDG PET or PET/CT results after concurrent chemoradiotherapy have a high negative predictive value (>95%), whereas the positive predictive value is only about 50%. However, when applied properly, FDG PET/CT can exclude residual disease in most patients, particularly patients with residual enlarged lymph nodes who would otherwise undergo neck dissection. In contrast to other malignancies, data are limited on the utility of (18)F-FDG PET for monitoring the response to induction chemotherapy in HNSCC or for assessing treatment response early during the course of definitive chemoradiotherapy. The proliferation marker (18)F-3'-deoxy-3'fluorothymidine is currently under study for this purpose. Beyond standard chemotherapy, newer treatment regimens in HNSCC take advantage of our improved understanding of tumor biology. Two molecules important in the progression of HNSCC are the epidermal growth factor receptor and the vascular endothelial growth factor (VEGF) and its receptor VEGF-R. Drugs attacking these molecules are now under study for HNSCC. PET probes have been developed for imaging the presence of these molecules in HNSCC and their inhibition by specific drug interaction; the relevance of these probes for response assessment in HNSCC will be discussed. Hypoxia is a common phenomenon in HNSCC and renders cancers resistant to chemo- and radiotherapy. Imaging and quantification of hypoxia with PET probes is under study and may become a prerequisite for overcoming chemo- and radioresistance using radiosensitizing drugs or hypoxia-directed irradiation techniques and for monitoring the response to these techniques in selected groups of patients. Although (18)F-FDG PET/CT will remain the major clinical tool for monitoring treatment in HNSCC, other PET probes may have a role in identifying patients who are likely to benefit from treatment strategies that include biologic agents such as epidermal growth factor receptor inhibitors or VEGF inhibitors.

Mutation-specific antibodies for the detection of EGFR mutations in non-small-cell lung cancer

PURPOSE

Activating mutations within the tyrosine kinase domain of epidermal growth factor receptor (EGFR) are found in approximately 10% to 20% of non-small-cell lung cancer (NSCLC) patients and are associated with response to EGFR inhibitors. The most common NSCLC-associated EGFR mutations are deletions in exon 19 and L858R mutation in exon 21, together accounting for 90% of EGFR mutations. To develop a simple, sensitive, and reliable clinical assay for the identification of EGFR mutations in NSCLC patients, we generated mutation-specific rabbit monoclonal antibodies against each of these two most common EGFR mutations and aimed to evaluate the detection of EGFR mutations in NSCLC patients by immunohistochemistry.

EXPERIMENTAL DESIGN

We tested mutation-specific antibodies by Western blot, immunofluorescence, and immunohistochemistry. In addition, we stained 40 EGFR genotyped NSCLC tumor samples by immunohistochemistry with these antibodies. Finally, with a panel of four antibodies, we screened a large set of NSCLC patient samples with unknown genotype and confirmed the immunohistochemistry results by DNA sequencing.

RESULTS

These two antibodies specifically detect the corresponding mutant form of EGFR by Western blotting, immunofluorescence, and immunohistochemistry. Screening a panel of 340 paraffin-embedded NSCLC tumor samples with these antibodies showed that the sensitivity of the immunohistochemistry assay is 92%, with a specificity of 99% as compared with direct and mass spectrometry-based DNA sequencing.

CONCLUSIONS

This simple assay for detection of EGFR mutations in diagnostic human tissues provides a rapid, sensitive, specific, and cost-effective method to identify lung cancer patients responsive to EGFR-based therapies.

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 and K-ras mutations along the spectrum of pulmonary epithelial tumors of the lung and elaboration of a combined clinicopathologic and molecular scoring system to predict clinical responsiveness to EGFR inhibitors

We tested 418 neoplasms along the whole spectrum of primary lung tumor histotypes for epidermal growth factor receptor (EGFR) and K-ras mutations. Clinicopathologic data from 154 patients undergoing treatment with EGFR tyrosine kinase inhibitors (TKIs) were retrospectively studied. A scoring system assigning a score for each positive or negative characteristic (+1, female sex, nonsmoking status, adenocarcinoma histotype, Asian ethnicity, and EGFR mutation; -1, current smoker and K-ras mutation; and 0, male sex, ex-smoker, nonadenocarcinoma histotype, and no mutations) was elaborated and tested with EGFR-TKI response. Salivary gland-type, mucin-rich, and neuroendocrine tumors do not harbor EGFR mutations. A subset of nonmucinous adenocarcinomas, not necessarily of the bronchioloalveolar type, is related to EGFR mutations. Three probability groups significantly correlating with response to EGFR-TKIs were identified. Of note, the addition of molecular results did not significantly change the predictive value obtained by the combination of clinicopathologic characteristics alone in this scoring system. K-ras mutations, significantly associated with the mucin-secreting type of adenocarcinoma, consistently predict lack of response in white patients.

Mutations and response to epidermal growth factor receptor inhibitors

Novel therapeutic agents targeting the epidermal growth factor receptor (EGFR) have improved outcomes for a subgroup of patients with colorectal, lung, head and neck, and pancreatic cancers. In these tumors, the EGFR activation turns on at least five different signaling pathways (RAS/mitogen-activated protein kinase, phospholipase C, phosphatidylinositol 3-kinase/AKT, signal transducer and activator of transcription, and SRC/FAK pathways), which are intimately interconnected, and frequent mutations involving either the receptor itself or downstream effectors have been found. Up to now, it seems that alterations at the EGFR level has major importance in EGFR tyrosine kinase inhibitor response, whereas modifications of downstream effectors could lead to treatment resistance. Furthermore, our understanding of the mechanism of the EGFR network activation provides new hypotheses on potential new anticancer drugs that may be effective.

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.

A phase II trial of gefitinib monotherapy in chemotherapy-naïve patients of 75 years or older with advanced non-small cell lung cancer

BACKGROUND

Gefitinib has shown modest activity in patients with recurrent non-small cell lung cancer (NSCLC) after platinum-based chemotherapy. However, the activity of gefitinib as first-line chemotherapy remains unclear, especially unknown in elderly patients. A multicenter phase II trial was conducted to evaluate the efficacy and tolerability of gefitinib for elderly patients with chemotherapy-naïve NSCLC.

METHODS

Elderly chemotherapy-naïve patients with advanced NSCLC, ECOG PS of 0-2, and adequate organ functions received 250 mg/day of gefitinib. The primary objective of this study was to determine the objective response rate (RR). Secondary endpoints were tolerability, disease-related symptom using lung cancer subscale (LCS) in FACT-L, progression free survival (PFS) and overall survival (OS). We investigated mutation status of the epidermal growth factor receptor (EGFR) gene in cases with available tumor samples.

RESULTS

Fifty patients were enrolled, of whom 49 were eligible. Median age (range) was 80 (75-90) years. Thirty-two patients were female (65%) and 40 patients had adenocarcinoma (82%). The objective RR was 25% (CI 95%, 13-39). Median survival time was 10 months (CI 95%, 7-20) and 1-year survival rate was 50%. The most frequent adverse events were skin disorders (76%). Fifteen patients (30%) experienced toxicities >/=grade 3. There were four patients with possible interstitial lung disease including two treatment-related deaths. Symptom improvement rate using LCS was 49% at 4 weeks of gefitinib therapy. Tumor samples from 17 patients were analyzed for EGFR mutation status. EGFR mutations were detected in tumor tissues from 7 patients, of which 5 had partial responses (71%).

CONCLUSIONS

Gefitinib monotherapy is effective and relatively well tolerated in chemotherapy-naïve elderly patients with advanced NSCLC. Gefitinib has potential as a first-line therapeutic option in elderly patients with advanced NSCLC.

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.

Epidermal growth factor receptor tyrosine kinase inhibitors as a first-line therapy for never-smokers with adenocarcinoma of the lung having asymptomatic synchronous brain metastasis

Considering whole-brain radiotherapy (WBRT) for asymptomatic brain metastases can reduce performance status and delay systemic treatment, primary chemotherapy can be a feasible alternative treatment. Good and rapid response to epidermal growth factor tyrosine kinase inhibitor (EGFR TKI) treatment makes this an attractive option for never-smokers with adenocarcinoma of the lung. Between January 2005 and August 2007, 23 Korean never-smoking patients with adenocarcinoma of the lung who had synchronous asymptomatic brain metastasis were consecutively treated with EGFR TKI therapy, either gefitinib 250 mg or erlotinib 150 mg once daily, as first-line treatment after giving informed consent, until disease progression, unacceptable toxicity or patient's refusal. They have not received either any prior chemotherapy or any radiotherapy including stereotactic radiosurgery. Objective tumor responses were assessed 1 month after treatment and then every 2 months or when clinically indicated. Out of the 23 patients treated, 16 achieved a PR and 3 experienced stable disease (SD) while 4 experienced progressive disease (PD), resulting in a response rate of 69.6% and a disease control rate of 82.6%. Intracranial tumor responses were observed in 17 patients (73.9%). After a median follow-up of 21.8 months, the median progression-free and overall survival (OS) time was 7.1 and 18.8 months, respectively. Eleven patients received WBRT with a median time-to-local-treatment for intracranial tumors of 19.3 months. In conclusion, EGFR TKI treatment showed promising antitumor activity against both intracranial and extracranial tumors in chemotherapy-naïve never-smokers with adenocarcinoma of the lung. Therefore, these agents should be considered as the treatment of choice in this clinical setting.

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.

Autocrine production of amphiregulin predicts sensitivity to both gefitinib and cetuximab in EGFR wild-type cancers

PURPOSE

Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors, gefitinib and erlotinib, lead to significant tumor regressions in 10% to 15% of non-small cell lung cancer (NSCLC) patients with EGFR activating mutations. However, 30% to 40% of NSCLC patients, majority of whom are EGFR wild-type, develop stable disease following EGFR tyrosine kinase inhibitor therapy. EGFR-directed antibodies (cetuximab) are effective treatments for head and neck squamous cell carcinomas, which seldom contain EGFR mutations. The determinant(s) of efficacy of EGFR-targeted therapies in EGFR wild-type cancers is not well defined.

EXPERIMENTAL DESIGN

We examined the relationship of EGFR ligands, EGF, transforming growth factor-alpha,and amphiregulin and the efficacy of gefitinib and cetuximab in EGFR wild-type NSCLC (n=10) and head and neck squamous cell carcinoma (n=4) cell lines. We compared amphiregulin expression using immunohistochemistry in EGFR wild-type NSCLC patients (n=24) that developed either stable or progressive disease following erlotinib or gefitinib treatment.

RESULTS

Cell lines which produced >or=20 pmol/L amphiregulin, as detected by an ELISA, were significantly more likely to be growth inhibited by both gefitinib and cetuximab than those that produced minimal or no amphiregulin. In these cell lines, both cetuximab and gefitinib led to cell cycle arrest at the G(1)-S boundary and was associated with preferential inhibition of extracellular signal-regulated kinase 1/2 but not Akt signaling. Amphiregulin expression was significantly higher in NSCLC patients that developed stable disease compared with those that developed disease progression following gefitinib or erlotinib treatment.

CONCLUSIONS

Amphiregulin expression may help select EGFR wild-type patients who are likely to develop stable disease from EGFR-targeted therapies.

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.