XL647--a multitargeted tyrosine kinase inhibitor: results of a phase II study in subjects with non-small cell lung cancer who have progressed after responding to treatment with either gefitinib or erlotinib. J Thorac Oncol. 2012;7:219-226. [PMID: 22011666 DOI: 10.1097/jto.0b013e31822eebf9]

Diastereoselective Formal 1,3-Dipolar Cycloaddition of Trifluoroethyl Amine-Derived Ketimines Enables the Desymmetrization of Cyclopentenediones

In this research, a metal-free diastereoselective formal 1,3-dipolar cycloaddition of N-2,2,2-trifluoroethylisatin ketimines and cyclopentene-1,3-diones which can efficiently lead to the desymmetrization of cyclopentene-1,3-diones is developed. With the developed protocol, a series of tetracyclic spirooxindoles containing pyrrolidine and cyclopentane subunits can be smoothly obtained with good results (up to 99% yield and 91:9 dr). Furthermore, the methodology can be extended to trifluoromethyl-substituted iminomalonate, and the corresponding formal [3+2] cycloaddition reaction affords bicyclic heterocycles containing fused pyrrolidine and cyclopentane moieties in moderate yields with >20:1 dr. The synthetic potential of the methodology is demonstrated by the scale-up experiment and by versatile transformations of the products.

Discovery of new thieno[2,3-d]pyrimidines as EGFR tyrosine kinase inhibitors for cancer treatment

Background: EGFR has been considered a vital molecular target in cancer management. Aim: The discovery of new thieno[2,3-d]pyrimidine derivatives as EGFR tyrosine kinase inhibitors. Methods: Nine derivatives were designed, synthesized and subjected to in vitro and in silico studies. Results: Compound 7a significantly inhibited the growth of HepG2 and PC3 cells for both EGFR wild-type and EGFRT790M. Compound 7a caused a significant apoptotic effect, arresting HepG2 cells' growth in the S and G2/M phases. Docking and molecular dynamics simulation studies confirmed the correct and stable binding modes of the synthesized compounds against the active sites. Conclusion: Compound 7a is a promising dual EGFR inhibitor for cancer treatment.

Hit Identification of a Novel Quinazoline Sulfonamide as a Promising EphB3 Inhibitor: Design, Virtual Combinatorial Library, Synthesis, Biological Evaluation, and Docking Simulation Studies

EphB3 is a major key player in a variety of cellular activities, including cell migration, proliferation, and apoptosis. However, the exact role of EphB3 in cancer remains ambiguous. Accordingly, new EphB3 inhibitors can increase the understanding of the exact roles of the receptor and may act as promising therapeutic candidates. Herein, a hybrid approach of structure-based design and virtual combinatorial library generated 34 quinazoline sulfonamides as potential selective EphB3 inhibitors. A molecular docking study over EphB3 predicted the binding affinities of the generated library, and the top seven hit compounds (3a and 4a–f), with GlideScore ≥ −6.20 Kcal/mol, were chosen for further MM-GBSA calculations. Out of the seven top hits, compound 4c showed the highest MM-GBSA binding free energy (−74.13 Kcal/mol). To validate these predicted results, compounds 3a and 4a–f were synthesized and characterized using NMR, HRMS, and HPLC. The biological evaluation revealed compound 4c as a potent EphB3 inhibitory lead (IC₅₀ = 1.04 µM). The screening of 4c over a mini-panel of kinases consisting of EGFR, Aurora A, Aurora B, CDK2/cyclin A, EphB1, EphB2, EphB4, ERBB2/HER2, and KDR/VEGFR2, showed a promising selective profile against EphB3 isoform. A dose-dependent assay of compound 4c and a molecular docking study over the different forms of EphB provided insights into the elicited biological activities and highlighted reasonable explanations of the selectivity.

The critical role of the interplays of EphrinB2/EphB4 and VEGF in the induction of angiogenesis

The significant role of VEGF (vascular endothelial growth factor) as an angiogenesis inducer is well recognized. Besides VEGF, EphrinB2/EphB4 also plays essential roles in vascular development and postnatal angiogenesis. Compared with classical proangiogenic factors, not only does EphrinB2/EphB4 promote sprouting of new vessels, it is also involved in the vessel maturation. Given their involvement in many physiologic and pathological conditions, EphB4 and EphrinB2 are increasingly recognized as attractive therapeutic targets for angiogenesis-related diseases through modulating their expression and function. Previous works mainly focused on the individual role of VEGF and EphrinB2/EphB4 in angiogenesis, respectively, but the correlation between EphrinB2/EphB4 and VEGF in angiogenesis has not been fully disclosed. Here, we summarize the structure and bidirectional signaling of EphrinB2/EphB4, provide an overview on the relationship between EphrinB2/EphB4 signaling and VEGF pathway in angiogenesis and highlight the associated potential usefulness in anti-angiogenetic therapy.

Secondary Resistant Mutations to Small Molecule Inhibitors in Cancer Cells

Secondary resistant mutations in cancer cells arise in response to certain small molecule inhibitors. These mutations inevitably cause recurrence and often progression to a more aggressive form. Resistant mutations may manifest in various forms. For example, some mutations decrease or abrogate the affinity of the drug for the protein. Others restore the function of the enzyme even in the presence of the inhibitor. In some cases, resistance is acquired through activation of a parallel pathway which bypasses the function of the drug targeted pathway. The Catalogue of Somatic Mutations in Cancer (COSMIC) produced a compendium of resistant mutations to small molecule inhibitors reported in the literature. Here, we build on these data and provide a comprehensive review of resistant mutations in cancers. We also discuss mechanistic parallels of resistance.

Targeting Neovasculature with Multitargeted Antiangiogenesis Tyrosine Kinase Inhibitors in Non-small Cell Lung Cancer

Chemotherapy has reached a plateau in the efforts for survival improvement in non-small cell lung cancer (NSCLC). The growing knowledge of NSCLC molecular pathobiology has led to the development of new treatments that target specific tumor functions. Angiogenesis is a tumor function leading to the formation of new tumor vessels that are crucial for its survival. Although vascular endothelial growth factor (VEGF) plays a primary role in angiogenesis, the inhibition of the VEGF pathway with VEGF-receptor (VEGFR) tyrosine kinase inhibitors (TKIs) is associated with a modest survival benefit due to the development of resistance by the tumor that has been mainly attributed to the up-regulation of other stimulators of angiogenesis. Thus, the use of multitargeted antiangiogenesis TKIs (MATKIs) for simultaneous inhibition of multiple angiogenic pathways has been proposed. This review summarizes data about novel treatment strategies incorporating the inhibition of angiogenesis with MATKIs in NSCLC. The data from all relevant studies shows that MATKIs do not offer additional survival benefit to currently available chemotherapeutic options in unselected NSCLC patients. However, the diversity in disease response to MATKI-containing regimens implies that specific patient subgroups may benefit from or be harmed by these agents. In this context, most studies agree that the VEGFR-targeting MATKIs are harmful in squamous NSCLC while specific MATKIs (i.e., motesanib, vandetanib and nintedanib) are associated with improved progression free survival in non-squamous NSCLC. However, overall survival benefit was found only in adenocarcinoma and Asian non-squamous NSCLC patients with the use of nintedanib and motesanib, respectively.

Afatinib increases sensitivity to radiation in non-small cell lung cancer cells with acquired EGFR T790M mutation

Afatinib is a second-generation of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor and has shown a significant clinical benefit in non-small cell lung cancer (NSCLC) patients with EGFR-activating mutations. However, the potential therapeutic effects of afatinib combining with other modalities, including ionizing radiation (IR), are not well understood. In this study, we developed a gefitinib-resistant cell subline (PC-9-GR) with a secondary EGFR mutation (T790M) from NSCLC PC-9 cells after chronic exposures to increasing doses of gefitinib. The presence of afatinib significantly increases the cell killing effect of radiation in PC-9-GR cells harboring acquired T790M, but not in H1975 cells with de novo T790M or in H460 cells that express wild-type EGFR. In PC-9-GR cells, afatinib remarkable blocks baseline of EGFR and ERK phosphorylations, and causes delay of IR-induced AKT phosphorylation. Afatinib treatment also leads to increased apoptosis and suppressed DNA damage repair in irradiated PC-9-GR cells, and enhanced tumor growth inhibition when combined with IR in PC-9-GR xenografts. Our findings suggest a potential therapeutic impact of afatinib as a radiation sensitizer in lung cancer cells harboring acquired T790M mutation, providing a rationale for a clinical trial with combination of afatinib and radiation in NSCLCs with EGFR T790M mutation.

Safety and efficacy of targeted agents monotherapy in advanced NSCLC

The emergence of targetted therapy has revolutionised the treatment of advanced NSCLC. Increasing numbers of driver genes and related targetted agents have supplied more powerful weapons for conquering NSCLC. Depending on whether there are clear targets and therapeutic effects, we can now rank targetted agents into three categories: agents with explicit targets and pure effects, agents with theoretical targets but with no effective biomarkers, agents with vague targets and lower effects. The latest clinical data on the safety and efficacy of monotherapy with three kinds of agents will be reviewed respectively in this article.

Inhibition of β-Catenin enhances the anticancer effect of irreversible EGFR-TKI in EGFR-mutated non-small-cell lung cancer with a T790M mutation

INTRODUCTION

Patients with non-small-cell lung cancer (NSCLC) with somatic activating mutations of the epidermal growth factor receptor gene (EGFR mutations) generally respond to EGFR tyrosine kinase inhibitors (EGFR-TKIs). β-Catenin is a key component of the Wnt/β-Catenin signal and is an important oncogene that is involved in the pathogenesis and progression of malignant tumors, especially cancer stem cells.

METHODS AND RESULTS

We found that EGFR-mutated NSCLC cell lines exhibited a high expression level of β-Catenin, compared with cell lines with the wild-type EGFR gene, and XAV939 (a β-Catenin inhibitor) enhanced the sensitivities to EGFR-TKI in EGFR-mutated NSCLC cell lines. In EGFR-mutated NSCLC cell lines with the acquired resistance threonine-to-methionine mutation in codon 790 (T790M) mutation, XAV939 enhanced the sensitivity of the cells to an irreversible EGFR-TKI but not a reversible EGFR-TKI. The combination of XAV939 and EGFR-TKIs strongly inhibited the β-Catenin signal and strongly decreased the phosphorylation of EGFR, compared with the use of EGFR-TKIs alone, suggesting an interaction between EGFR and the β-Catenin signal. The stem cell-like properties of the EGFR-mutated cell line carrying the T790M mutation were inhibited by XAV939 and BIBW2992 (an irreversible EGFR-TKI). Furthermore, the stem cell-like properties were strongly inhibited by a combination of both the agents. A xenograft study demonstrated that β-Catenin knockdown enhanced the antitumor effect of BIBW2992 in the EGFR-mutated NSCLC cell line carrying the T790M mutation.

CONCLUSION

Our findings indicate that β-Catenin might be a novel therapeutic target in EGFR-mutated NSCLC carrying the T790M mutation.

Differential protein expression and oncogenic gene network link tyrosine kinase ephrin B4 receptor to aggressive gastric and gastroesophageal junction cancers

Transmembrane tyrosine-kinase Ephrin receptors promote tumor progression and/or metastasis of several malignancies including leukemia, follicular lymphoma, glioma, malignant pleural mesothelioma, papillary thyroid carcinoma, sarcomas and ovarian, breast, bladder and non-small cell lung cancers. They also drive intestinal stem cell proliferation and positioning, control intestinal tissue boundaries and are involved in liver, pancreatic and colorectal cancers, indicating involvement in additional digestive system malignancies. We investigated the role of Ephrin-B4 receptor (EPHB4), and its ligand EFNB2, in gastric and gastroesophageal junction cancers in patient cohorts through computational, mathematical, molecular and immunohistochemical analyses. We show that EPHB4 is upregulated in preneoplastic gastroesophageal lesions and its expression further increased in gastroesophageal cancers in several independent cohorts. The closely related EPHB6 receptor, which also binds EFNB2, was downregulated in all tested cohorts, consistent with its tumor-suppressive properties in other cancers. EFNB2 expression is induced in esophageal cells by acidity, suggesting that gastroesophageal reflux disease (GERD) may constitute an early triggering event in activating EFNB2-EPHB4 signaling. Association of EPHB4 to both Barrett's esophagus and to advanced tumor stages, and its overexpression at the tumor invasion front and vascular endothelial cells intimate the notion that EPHB4 may be associated with multiple steps of gastroesophageal tumorigenesis. Analysis of oncogenomic signatures uncovered the first EPHB4-associated gene network (false discovery rate: 7 × 10(-90) ) composed of a five-transcription factor interconnected gene network that drives proliferation, angiogenesis and invasiveness. The EPHB4 oncogenomic network provides a molecular basis for its role in tumor progression and points to EPHB4 as a potential tumor aggressiveness biomarker and drug target in gastroesophageal cancers.

Treating acquired resistance to EGFR-tyrosine kinase inhibitors:still a work in progress

While most patients with metastatic non-small cell lung cancer (NSCLC) containing sensitizing mutations in the epidermal growth factor receptor (EGFR) gene will achieve an objective response to EGFR tyrosine kinase inhibitors (TKIs) such as erlotinib or gefitinib, patients inevitably develop resistance to these agents. One of the strategies being tested to overcome acquired resistance to EGFR TKIs is the use of irreversible EGFR inhibitors such as afatinib. In the randomized phase 2b/3 LUX-Lung 1 trial in advanced NSCLC patients who progressed after at least 12 weeks of benefit from EGFR TKIs, afatinib failed to improve overall survival compared to placebo. Although the liberal entry criteria likely allowed the inclusion of some patients without true acquired resistance, the failure of this study calls into question the viability of irreversible EGFR inhibitors in this patient population.

Therapeutic strategies utilized in the setting of acquired resistance to EGFR tyrosine kinase inhibitors

Patients with EGFR-mutant lung cancer derive significant therapeutic benefit from treatment with EGFR tyrosine kinase inhibitors (TKI). Unfortunately, acquired resistance is an inevitable consequence of this treatment strategy, with a broad variety of resistance mechanisms including acquired EGFR mutations (e.g., T790M) and activation of bypass signaling pathways, such as MET and HER2. Several therapeutic strategies hypothesized to delay or overcome resistance have been tested in clinical trials, including "next-generation" EGFR TKIs and rational combinations of targeted agents. However, to date, there are no FDA-approved therapies for patients with acquired resistance to first-line EGFR TKI therapy. There remains a critical need for more effective and better tailored treatments in this setting to match treatments to the individual patient and specific resistance mechanism at hand. In this review, we discuss known mechanisms of resistance to first-line EGFR TKI therapy and describe previous and ongoing strategies to overcome resistance.

Review of the current targeted therapies for non-small-cell lung cancer

The last decade has witnessed the development of oncogene-directed targeted therapies that have significantly changed the treatment of non-small-cell lung cancer (NSCLC). In this paper we review the data demonstrating efficacy of gefitinib, erlotinib, and afatinib, which target the epidermal growth factor receptor (EGFR), and crizotinib which targets anaplastic lymphoma kinase (ALK). We discuss the challenge of acquired resistance to these small-molecular tyrosine kinase inhibitors and review promising agents which may overcome resistance, including the EGFR T790M-targeted agents CO-1686 and AZD9291, and the ALK-targeted agents ceritinib (LDK378), AP26113, alectinib (CH/RO5424802), and others. Emerging therapies directed against other driver oncogenes in NSCLC including ROS1, HER2, and BRAF are covered as well. The identification of specific molecular targets in a significant fraction of NSCLC has led to the personalized deployment of many effective targeted therapies, with more to come.

Moving from histological subtyping to molecular characterization: new treatment opportunities in advanced non-small-cell lung cancer

Over the last 10 years, the systemic treatment of advanced non-small-cell lung cancer has progressively moved away from the 'one-size-fits-all' approach to histological subtyping. Currently, there is a progressive implementation of targeted therapies based on specific molecular characteristics such as the EGF receptor sensitizing mutations and the anaplastic lymphoma kinase rearrangements. Despite the availability of effective agents against these abnormalities, acquired resistance is still a major issue. A new generation of tyrosine kinase inhibitors for EGF receptor and anaplastic lymphoma kinase targeting acquired resistance mechanisms have been recently investigated. Several promising tyrosine kinase inhibitors that hit other targets are also in clinical development, including: rat sarcoma gene/MEK, BRAF1, PIK3A, c-mesenchymal-epithelial transition, c-ros oncogene 1, rearranged during transfection, human EGFR 2, FGFR, VEGFR, PDGFR and discoidin death receptor 2. Furthermore, new advances in immunology have been achieved through the discovery of vaccines and immune checkpoint pathways such as the cytotoxic T-lymphocyte-associated antigen-4, programmed cell death protein 1 and its ligands.

Dual inhibition of EGFR with afatinib and cetuximab in kinase inhibitor-resistant EGFR-mutant lung cancer with and without T790M mutations

EGFR-mutant lung cancers responsive to reversible EGFR inhibitors (gefitinib/erlotinib) develop acquired resistance, mediated by second-site EGFR T790M mutation in >50% of cases. Preclinically, afatinib (irreversible ErbB family blocker) plus cetuximab (anti-EGFR monoclonal antibody) overcomes T790M-mediated resistance. This phase Ib study combining afatinib and cetuximab enrolled heavily pretreated patients with advanced EGFR-mutant lung cancer and acquired resistance to erlotinib/gefitinib. Patients provided post-acquired-resistance tumor samples for profiling EGFR mutations. Among 126 patients, objective response rate (overall 29%) was comparable in T790M-positive and T790M-negative tumors (32% vs. 25%; P = 0.341). Median progression-free survival was 4.7 months (95% confidence interval, 4.3-6.4), and the median duration of confirmed objective response was 5.7 months (range, 1.8-24.4). Therapy-related grade 3/4 adverse events occurred in 44%/2% of patients. Afatinib-cetuximab demonstrated robust clinical activity and a manageable safety profile in EGFR-mutant lung cancers with acquired resistance to gefitinib or erlotinib, both with and without T790M mutations, warranting further investigation.

SIGNIFICANCE

This article reports the results of a trial combining afatinib and cetuximab in patients with acquired resistance and details the first clinical proof-of-concept for the preclinical hypothesis that a significant proportion of tumors in patients with acquired resistance to gefitinib/erlotinib remain dependent on EGFR signaling for survival.

Management of EGFR-mutant non-small-cell lung cancer patients after first-line reversible EGF receptor-tyrosine kinase inhibitors

SUMMARY Lung cancers harboring mutations in the EGFR respond to EGF receptor-tyrosine kinase inhibitor, which at present represent the most appropriate treatment for EGFR mutation-positive advanced non-small-cell lung cancer. Unfortunately drug resistance invariably emerges with different known mechanisms, including the EGFR T790M mutation, MET gene amplification, EGFR amplification, mutations in the PIK3CA gene, mutations in the HER2 gene, IGF1R amplification, transformation of non-small-cell lung cancer into small-cell lung cancer and moreover epithelial-to-mesenchymal transition. Various strategies to manage secondary resistance have been explored and in this review we will analyze scientific data in support of these different strategies to assess the most adequate to use in relation to the progression disease.

Second generation tyrosine kinase inhibitors for the treatment of metastatic non-small-cell lung cancer

Backgruond

Since their first description, activating epidermal growth factor receptor (EGFR) mutations identify a distinct clinical entity of patients with non-small-cell lung cancer (NSCLC).

Findings

New targeted therapies for molecularly selected NSCLC are changing the natural history of the disease, with results superior to standard chemotherapy as demonstrated in large phase III studies with first generation EGFR tyrosine kinase inhibitors (TKIs) erlotinib and gefitinib. However, after an initial response, all patients inevitably progress and several mechanisms including a secondary mutation in exon 20 of the EGFR gene (T790M) or MET or HER2 amplifications are responsible for acquired resistance (AR). In clinical practice few options are available for patients with AR, and several new agents or strategies are currently under investigation, including second generation TKIs.

Conclusions

Aim of the present review is to present available data on new EGFR-TKIs and to discuss how these agents could overcome AR to erlotinib or gefitinib.

Preclinical and clinical development of afatinib: a focus on breast cancer and squamous cell carcinoma of the head and neck

ABSTRACT: Aberrant signaling of the ErbB family of receptors plays an integral role in the tumorigenesis of many cancer types, including head and neck squamous cell carcinoma (HNSCC) and breast cancer (BC). Significant research efforts have focused on developing new treatments that target ErbB family members, with the last decade seeing the approval of small-molecule tyrosine kinase inhibitors and monoclonal antibodies that inhibit ErbB signaling. However, treatment resistance is an ever-growing problem and, therefore, new therapies are being investigated to overcome this hurdle. Afatinib is an irreversible ErbB family blocker that has demonstrated potent anti-tumor activity in preclinical models and has displayed clinical efficacy in patients with non-small-cell lung cancer, and activity in HNSCC and BC. Here, the preclinical and clinical development of afatinib in the treatment of non-small-cell lung cancer, HNSCC and BC is described in the context of currently approved agents.

Targeted therapies in development for non-small cell lung cancer

The iterative discovery in various malignancies during the past decades that a number of aberrant tumorigenic processes and signal transduction pathways are mediated by "druggable" protein kinases has led to a revolutionary change in drug development. In non-small cell lung cancer (NSCLC), the ErbB family of receptors (e.g., EGFR [epidermal growth factor receptor], HER2 [human epidermal growth factor receptor 2]), RAS (rat sarcoma gene), BRAF (v-raf murine sarcoma viral oncogene homolog B1), MAPK (mitogen-activated protein kinase) c-MET (c-mesenchymal-epithelial transition), FGFR (fibroblast growth factor receptor), DDR2 (discoidin domain receptor 2), PIK3CA (phosphatidylinositol-4,5-bisphosphate3-kinase, catalytic subunit alpha)), PTEN (phosphatase and tensin homolog), AKT (protein kinase B), ALK (anaplastic lym phoma kinase), RET (rearranged during transfection), ROS1 (reactive oxygen species 1) and EPH (erythropoietin-producing hepatoma) are key targets of various agents currently in clinical development. These oncogenic targets exert their selective growth advantage through various intercommunicating pathways, such as through RAS/RAF/MEK, phosphoinositide 3-kinase/AKT/mammalian target of rapamycin and SRC-signal transduction and transcription signaling. The recent clinical studies, EGFR tyrosine kinase inhibitors and crizotinib were considered as strongly effective targeted therapies in metastatic NSCLC. Currently, five molecular targeted agents were approved for treatment of advanced NSCLC: Gefitinib, erlotinib and afatinib for positive EGFR mutation, crizotinib for positive echinoderm microtubule-associated protein-like 4 (EML4)-ALK translocation and bevacizumab. Moreover, oncogenic mutant proteins are subject to regulation by protein trafficking pathways, specifically through the heat shock protein 90 system. Drug combinations affecting various nodes in these signaling and intracellular processes are predicted and demonstrated to be synergistic and advantageous in overcoming treatment resistance compared with monotherapy approaches. Understanding the role of the tumor microenvironment in the development and maintenance of the malignant phenotype provided additional therapeutic approaches as well. More recently, improved knowledge on tumor immunology has set the stage for promising immunotherapies in NSCLC. This review will focus on the rationale for the development of targeted therapies in NSCLC and the various strategies employed in preventing or overcoming the inevitable occurrence of treatment resistance.

Therapeutic perspectives of Eph-ephrin system modulation

Eph receptors are the largest class of kinase receptors and, together with their ligands ephrins, they have a primary role in embryogenesis. Their expression has been found deregulated in several cancer tissues and, in many cases, abnormal levels of these proteins have been correlated to a poor prognosis. Recently, the Eph-ephrin system was found to be deregulated in other pathological processes, involving the nervous and cardiovascular systems. The increasing body of evidence supports the Eph-ephrin system as a target not only for the treatment of solid tumors, but also to face other critical diseases such as amyotrophic lateral sclerosis and diabetes driving current efforts toward the development of pharmacological tools potentially able to treat these pathologies.

Circulating cell-free DNA: a potential biomarker in lung cancer

SUMMARY Cell-free DNA (cfDNA) is a promising, noninvasive tumor ‘liquid biopsy’ with quantitative and qualitative significance. Circulating cfDNA levels are raised in cancer patients and cfDNA exhibits genetic and epigenetic changes found in the underlying tumor. In lung cancer patients, cfDNA levels and tumor-associated genetic and epigenetic changes have been assessed as diagnostic, prognostic and predictive biomarkers. To date, many small studies have been reported with contradictory results. Their interpretation is hampered by differences in methodology and the selection of patients and controls. The treatment of lung cancer is increasingly guided by molecular subtyping, but access to tumor tissue is limited and cfDNA represents an attractive alternative. Moreover, repeated sampling of cfDNA is feasible and cfDNA may be more representative of tumor heterogeneity than a small biopsy sample. However, the establishment of robust and standardized protocols for blood sampling, processing, storage, DNA extraction and analysis are required before cfDNA biomarkers can be utilized in clinical practice.

Lung Cancer Biomarkers: Present Status and Future Developments

The publication of the “Molecular Testing Guideline for Selection of Lung Cancer Patients for EGFR and ALK Tyrosine Kinase Inhibitors: Guideline From the College of American Pathologists, International Association for the Study of Lung Cancer, and Association for Molecular Pathology” has now provided a guideline for biomarker testing for first-generation lung cancer tyrosine kinase inhibitors. Biomarker testing has forever altered the role of pathologists in the management of patients with lung cancer. Current, unresolved issues in the precision medicine of lung cancer will be addressed by the development of new biomarker tests, new drugs, and new test technologies and by improvement in the cost to benefit ratio of biomarker testing.

LUX-Lung 4: a phase II trial of afatinib in patients with advanced non-small-cell lung cancer who progressed during prior treatment with erlotinib, gefitinib, or both

PURPOSE

New molecular targeted agents are needed for patients with non-small-cell lung cancer (NSCLC) who progress while receiving erlotinib, gefitinib, or both. Afatinib, an oral irreversible ErbB family blocker, has preclinical activity in epidermal growth factor receptor (EGFR [ErbB1]) mutant models with EGFR-activating mutations, including T790M.

PATIENTS AND METHODS

This was a Japanese single-arm phase II trial conducted in patients with stage IIIB to IV pulmonary adenocarcinoma who progressed after ≥ 12 weeks of prior erlotinib and/or gefitinib. Patients received afatinib 50 mg per day. The primary end point was objective response rate (complete response or partial response) by independent review. Secondary end points included progression-free survival (PFS), overall survival (OS), and safety.

RESULTS

Of 62 treated patients, 45 (72.6%) were EGFR mutation positive in their primary tumor according to local and/or central laboratory analyses. Fifty-one patients (82.3%) fulfilled the criteria of acquired resistance to erlotinib and/or gefitinib. Of 61 evaluable patients, five (8.2%; 95% CI, 2.7% to 18.1%) had a confirmed objective response rate (partial response). Median PFS was 4.4 months (95% CI, 2.8 to 4.6 months), and median OS was 19.0 months (95% CI, 14.9 months to not achieved). Two patients had acquired T790M mutations: L858R + T790M, and deletion in exon 19 + T790M; they had stable disease for 9 months and 1 month, respectively. The most common afatinib-related adverse events (AEs) were diarrhea (100%) and rash/acne (91.9%). Treatment-related AEs leading to afatinib discontinuation were experienced by 18 patients (29%), of whom four also had progressive disease.

CONCLUSION

Afatinib demonstrated modest but noteworthy efficacy in patients with NSCLC who had received third- or fourth-line treatment and who progressed while receiving erlotinib and/or gefitinib, including those with acquired resistance to erlotinib, gefitinib, or both.

Nonsmall cell lung cancer therapy: insight into multitargeted small-molecule growth factor receptor inhibitors

To date, lung cancer is the leading cause of cancer-related death worldwide, among which nonsmall cell lung cancer (NSCLC) comprises about 85%. Taking into account the side effects of surgery, radiation, platinum-based doublet chemotherapy, and the growth self-sufficiency characteristic of cancer cells, drugs have been discovered toward growth factor receptor (GFR) to treat NSCLC. As expected, these drugs provide a greater benefit. To increase the efficacy of such growth factor receptor tyrosine kinase inhibitors (RTKIs), coinhibition of GFR signaling pathways and combination of inhibitors along with radiation or chemotherapy have drew intense insight. Although clinical trials about single-agent RTKIs or their combination strategies suggest their increase potency against cancer, they are not beyond adverse effects, and sometimes the effects are more deadly than chemotherapy. Nevertheless the hope for RTKIs may be proved true by further researches and digging deep into cancer therapeutics.

[Advanced research on T790M mutation in non-small cell lung cancer]

携带表皮生长因子受体（epidermal growth factor receptor, EGFR）基因活性突变的非小细胞肺癌（non-small cell lung cancer, NSCLC）晚期患者使用EGFR-受体酪氨酸激酶抑制剂（tyrosine kinase inhibitor, TKI）治疗后具有较好的临床获益，但大部分患者在使用该药治疗10个月后出现耐药现象。研究发现EGFR基因20号外显子T790M基因突变是导致EGFR-TKI耐药的最主要因素，但其作用机制至今未明。目前的研究结果显示T790M基因突变是一个独立的、好的预后因素，但其能否作为EGFR-TKI的疗效预测因子仍存在争议。近年来，针对NSCLC肿瘤中T790M基因突变的检测技术不断更新，针对T790M耐药的新的治疗策略也不断涌现。本文就NSCLC中T790M基因突变的耐药机制、临床意义、检测方法及应对策略等方面的最新研究进展进行综述。

Genomics of squamous cell lung cancer

Approximately 30% of patients with non-small cell lung cancer have the squamous cell carcinoma (SQCC) histological subtype. Although targeted therapies have improved outcomes in patients with adenocarcinoma, no agents are currently approved specifically for use in SQCC. The Cancer Genome Atlas (TCGA) recently published the results of comprehensive genomic analyses of tumor samples from 178 patients with SQCC of the lung. In this review, we briefly discuss key molecular aberrations reported by TCGA and other investigators and their potential therapeutic implications. Carefully designed preclinical and clinical studies based on these large-scale genomic analyses are critical to improve the outcomes of patients with SQCC of lung in the near future.

Novel small molecule EGFR inhibitors as candidate drugs in non-small cell lung cancer

In the last decade, better understanding of the role of epidermal growth factor receptor in the pathogenesis and progression of non-small cell lung cancer has led to a revolution in the work-up of these neoplasms. Tyrosine kinase inhibitors, such as erlotinib and gefitinib, have been approved for the treatment of non-small cell lung cancer, demonstrating an improvement in progression-free and overall survival, particularly in patients harboring activating EGFR mutations. Nevertheless, despite initial responses and long-lasting remissions, resistance to tyrosine kinase inhibitors invariably develops, most commonly due to the emergence of secondary T790M mutations or to the amplification of mesenchymal-epithelial transition factor (c-Met), which inevitably leads to treatment failure. Several clinical studies are ongoing (http://www.clinicaltrials.gov), aimed to evaluate the efficacy and toxicity of combined approaches and to develop novel irreversible or multitargeted tyrosine kinase inhibitors and mutant-selective inhibitors to overcome such resistance. This review is an overview of ongoing Phase I, II, and III trials of novel small molecule epidermal growth factor receptor inhibitors and combinations in non-small cell lung cancer patients.

Afatinib: emerging next-generation tyrosine kinase inhibitor for NSCLC

The discovery of epidermal growth-factor receptor (EGFR)-activating mutations and the introduction of oral EGFR tyrosine kinase inhibitors (EGFR-TKIs) have expanded the treatment options for patients with non-small cell lung cancer. The first two reversible EGFR-TKIs, erlotinib and gefitinib, are approved for use in the first-line setting in patients with known EGFR-activating mutations and in the second- and third-line settings for all NSCLC patients. These first-generation EGFR-TKIs improve progression-free survival when compared to chemotherapy in patients with EGFR-activating mutations in the first-line setting. However, nearly all patients develop resistance to EGFR-directed agents. There is a need for further therapy options for patients with disease progression after treatment with reversible EGFR-TKIs. Afatinib is an irreversible ErbB family blocker that inhibits EGFR, HER2, and HER4. In vitro and in vivo, afatinib have shown increased inhibition of the common EGFR-activating mutations as well as the T790M resistance mutation when compared to erlotinib and gefitinib. Clinically, afatinib has been evaluated in the LUX-Lung series of trials, with improvement in progression-free survival reported in patients with EGFR-activating mutations in both first- and second-/third-line settings when compared to chemotherapy. Further investigation is needed to determine the precise role that afatinib will play in the treatment of patients with non-small cell lung cancer and EGFR-activating mutations.

Second-generation epidermal growth factor receptor tyrosine kinase inhibitors in lung cancers

EGFR mutations identify patients who are more likely to respond to treatment with epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) than cytotoxic chemotherapy. The distinct success of the first-generation EGFR TKIs erlotinib and gefitinib has been accompanied by the observation that acquired resistance to these treatments develops after a median of 1 year of treatment. Newer, second-generation EGFR TKIs have been developed with the intent to delay or overcome acquired resistance by the broader inhibition of kinases (eg, HER2 and vascular endothelial growth factor receptor) and/or altering the interactions with EGFR through irreversibly binding to the kinase domain. This article discusses many of these agents (including afatinib, dacomitinib, XL647, AP26113, and CO-1686) which have the potential for greater efficacy compared with first-generation EGFR TKIs, and may also have clinical activity against other oncogenic mutations within the EGFR family, including HER2.

Lung cancer genotype-based therapy and predictive biomarkers: present and future

CONTEXT

The advent of genotype-based therapy and predictive biomarkers for lung cancer has thrust the pathologist into the front lines of precision medicine for this deadly disease.

OBJECTIVE

To provide the clinical background, current status, and future perspectives of molecular targeted therapy for lung cancer patients, including the pivotal participation of the pathologist.

DATA SOURCES

Data were obtained from review of the pertinent peer-reviewed literature.

CONCLUSIONS

First-generation tyrosine kinase inhibitors have produced clinical response in a limited number of non-small cell lung cancers demonstrated to have activating mutations of epidermal growth factor receptor or anaplastic lymphoma kinase rearrangements with fusion partners. Patients treated with first-generation tyrosine kinase inhibitors develop acquired resistance to their therapy. Ongoing investigations of second-generation tyrosine kinase inhibitors and new druggable targets as well as the development of next-generation genotyping and new antibodies for immunohistochemistry promise to significantly expand the pathologist's already crucial role in precision medicine of lung cancer.

MicroRNA-133b inhibits the growth of non-small-cell lung cancer by targeting the epidermal growth factor receptor

Both the deregulation of microRNAs and epidermal growth factor receptor (EGFR) are emerging as important factors in non-small-cell lung cancer (NSCLC). Here, miR-133b was found to be associated with tumor stage, the extent of regional lymph node involvement, stage, visceral pleura or vessel invasion and EGFR mRNA expression in Chinese patients with NSCLC. Bioinformatic analysis and luciferase reporter assay revealed that miR-133b can interact specifically with the 3'-UTR of EGFR mRNA. Functionally, miR-133b transfection showed regulatory activity in translationally repressing EGFR mRNA. Moreover, miR-133b transfection may modulate apoptosis, invasion and sensitivity to EGFR-TKI through the EGFR signaling pathways, especially in EGFR-addicted NSCLC cells. Taken together, our findings show that miR-133b can inhibit cell growth of NSCLC through targeting EGFR and regulating its downstream signaling pathway. This finding has important implications for the development of targeted therapeutics for a number of EGFR-addicted cancers.

EGFR-mutant lung adenocarcinomas treated first-line with the novel EGFR inhibitor, XL647, can subsequently retain moderate sensitivity to erlotinib

INTRODUCTION

EGFR-mutant lung cancers are sensitive to EGFR tyrosine kinase inhibitors (TKIs). Unfortunately, they develop resistance, often due to acquisition of a second-site mutation (T790M). Current EGFR TKIs select for T790M in preclinical models of acquired resistance. We explored whether all EGFR TKIs similarly select for the T790M mutation using data from early clinical trials and established in vitro models of acquired resistance.

METHODS

We analyzed the clinical characteristics of eight patients with metastatic EGFR-mutant lung adenocarcinoma who were treated first-line with XL647 and then progressed. XL647 is an ATP-competitive inhibitor of EGFR, HER2, KDR, and EPHB4. Additional molecular preclinical studies were performed to characterize resistance.

RESULTS

Four patients displayed confirmed partial responses (PRs), three patients had unconfirmed PRs, and one patient displayed stable disease. Only one of five patients' tumor samples available for analysis after disease progression harbored the T790M mutation. Eight patients subsequently received erlotinib, with (n = 3) or without (n = 5) chemotherapy. Three of five patients treated with single-agent erlotinib derived additional benefit, staying on drug up to 9 months. EGFR-mutant PC-9 cells with acquired resistance to XL647 did not harbor the T790M mutation, displayed a distinct mRNA profile from PC-9 cells with T790M-mediated resistance, and were moderately sensitive to erlotinib in growth inhibition assays. Crystal structure analyses of XL647/EGFR T790M did not reveal a different binding mode from that of erlotinib.

CONCLUSIONS

The findings of this exploratory study suggest that different EGFR TKIs may select for distinct mechanisms of resistance. These results raise the possibility that different EGFR TKIs could be sequentially used to improve outcomes in patients with EGFR-mutant lung cancer. Further work investigating this hypothesis is warranted.

Afatinib versus placebo for patients with advanced, metastatic non-small-cell lung cancer after failure of erlotinib, gefitinib, or both, and one or two lines of chemotherapy (LUX-Lung 1): a phase 2b/3 randomised trial

BACKGROUND

Afatinib, an irreversible ErbB-family blocker, has shown preclinical activity when tested in EGFR mutant models with mutations that confer resistance to EGFR tyrosine-kinase inhibitors. We aimed to assess its efficacy in patients with advanced lung adenocarcinoma with previous treatment failure on EGFR tyrosine-kinase inhibitors.

METHODS

In this phase 2b/3 trial, we enrolled patients with stage IIIB or IV adenocarcinoma and an Eastern Cooperative Oncology Group performance (ECOG) performance score of 0-2 who had received one or two previous chemotherapy regimens and had disease progression after at least 12 weeks of treatment with erlotinib or gefitinib. We used a computer-generated sequence to randomly allocate patients (2:1) to either afatinib (50 mg per day) or placebo; all patients received best supportive care. Randomisation was done in blocks of three and was stratified by sex and baseline ECOG performance status (0-1 vs 2). Investigators, patients, and the trial sponsor were masked to treatment assignment. The primary endpoint was overall survival (from date of randomisation to death), analysed on an intention-to-treat basis. This study is registered with ClinicalTrials.gov, number NCT00656136.

FINDINGS

Between May 26, 2008, and Sept 21, 2009, we identified 697 patients, 585 of whom were randomly allocated to treatment (390 to afatinib, 195 to placebo). Median overall survival was 10·8 months (95% CI 10·0-12·0) in the afatinib group and 12·0 months (10·2-14·3) in the placebo group (hazard ratio 1·08, 95% CI 0·86-1·35; p=0·74). Median progression-free survival was longer in the afatinib group (3·3 months, 95% CI 2·79-4·40) than it was in the placebo group (1·1 months, 0·95-1·68; hazard ratio 0·38, 95% CI 0·31-0·48; p<0·0001). No complete responses to treatment were noted; 29 (7%) patients had a partial response in the afatinib group, as did one patient in the placebo group. Subsequent cancer treatment was given to 257 (68%) patients in the afatinib group and 153 (79%) patients in the placebo group. The most common adverse events in the afatinib group were diarrhoea (339 [87%] of 390 patients; 66 [17%] were grade 3) and rash or acne (305 [78%] patients; 56 [14%] were grade 3). These events occurred less often in the placebo group (18 [9%] of 195 patients had diarrhoea; 31 [16%] had rash or acne), all being grade 1 or 2. Drug-related serious adverse events occurred in 39 (10%) patients in the afatinib group and one (<1%) patient in the placebo group. We recorded two possibly treatment-related deaths in the afatinib group.

INTERPRETATION

Although we recorded no benefit in terms of overall survival with afatinib (which might have been affected by cancer treatments given after progression in both groups), our findings for progression-free survival and response to treatment suggest that afatinib could be of some benefit to patients with advanced lung adenocarcinoma who have failed at least 12 weeks of previous EGFR tyrosine-kinase inhibitor treatment.

FUNDING

Boehringer Ingelheim Inc.

EGFR exon 19 insertions: a new family of sensitizing EGFR mutations in lung adenocarcinoma

PURPOSE

Epidermal growth factor receptor (EGFR) genotyping is now standard in the management of advanced lung adenocarcinoma, as this biomarker predicts marked benefit from treatment with EGFR tyrosine kinase inhibitors (TKI). EGFR exon 19 insertions are a poorly described family of EGFR mutations, and their association with EGFR-TKI sensitivity in lung adenocarcinoma is uncertain.

EXPERIMENTAL DESIGN

Patients with lung cancers harboring EGFR exon 19 insertions were studied. The predicted effects of the insertions on the structure of the EGFR protein were examined, and EGFR exon 19 insertions were introduced into Ba/F3 cells to assess oncogenicity and in vitro sensitivity to EGFR-TKIs. In patients receiving TKI, response magnitude was assessed with serial computed tomographic (CT) measurement.

RESULTS

Twelve tumors harboring EGFR exon 19 insertions were identified; patients were predominately female (92%) and never-smokers (75%). The 11 specimens available for full sequencing all showed an 18-bp insertion that resulted in the substitution of a Pro for Leu at residue 747. The mutant EGFR transformed the Ba/F3 cells, which were then sensitive to EGFR-TKI. Six patients with measurable disease received TKI and five had a response on serial CT.

CONCLUSIONS

EGFR exon 19 insertions are a newly appreciated family of EGFR-TKI-sensitizing mutations, and patients with tumors harboring these mutations should be treated with EGFR-TKI. While these mutations may be missed through the use of some mutation-specific assays, the addition of PCR product size analysis to multigene assays allows sensitive detection of both exon 19 insertion and deletion mutations.

EGFR exon 19 insertions: a new family of sensitizing EGFR mutations in lung adenocarcinoma

PURPOSE

Epidermal growth factor receptor (EGFR) genotyping is now standard in the management of advanced lung adenocarcinoma, as this biomarker predicts marked benefit from treatment with EGFR tyrosine kinase inhibitors (TKI). EGFR exon 19 insertions are a poorly described family of EGFR mutations, and their association with EGFR-TKI sensitivity in lung adenocarcinoma is uncertain.

EXPERIMENTAL DESIGN

Patients with lung cancers harboring EGFR exon 19 insertions were studied. The predicted effects of the insertions on the structure of the EGFR protein were examined, and EGFR exon 19 insertions were introduced into Ba/F3 cells to assess oncogenicity and in vitro sensitivity to EGFR-TKIs. In patients receiving TKI, response magnitude was assessed with serial computed tomographic (CT) measurement.

RESULTS

Twelve tumors harboring EGFR exon 19 insertions were identified; patients were predominately female (92%) and never-smokers (75%). The 11 specimens available for full sequencing all showed an 18-bp insertion that resulted in the substitution of a Pro for Leu at residue 747. The mutant EGFR transformed the Ba/F3 cells, which were then sensitive to EGFR-TKI. Six patients with measurable disease received TKI and five had a response on serial CT.

CONCLUSIONS

EGFR exon 19 insertions are a newly appreciated family of EGFR-TKI-sensitizing mutations, and patients with tumors harboring these mutations should be treated with EGFR-TKI. While these mutations may be missed through the use of some mutation-specific assays, the addition of PCR product size analysis to multigene assays allows sensitive detection of both exon 19 insertion and deletion mutations.