Osimertinib for pretreated EGFR Thr790Met-positive advanced non-small-cell lung cancer (AURA2): a multicentre, open-label, single-arm, phase 2 study

EGFR TKI as first-line treatment for patients with advanced EGFR mutation-positive non-small-cell lung cancer

After the discovery of activating mutations in EGFR, EGFR tyrosine kinase inhibitors (TKIs) have been introduced into the first-line treatment of non-small-cell lung cancer (NSCLC). A series of studies have shown that EGFR TKI monotherapy as first-line treatment can benefit NSCLC patients harbouring EGFR mutations. Besides, combination strategies based on EGFR TKIs in the first line treatment have also been proved to delay the occurrence of resistance. In this review, we summarize the scientific literature and evidence of EGFR TKIs as first-line therapy from the first-generation EGFR TKIs to conceptually proposed fourth-generation EGFR TKI, and also recommend the application of monotherapy and combination therapies of the EGFR-based targeted therapy with other agents such as chemotherapy, anti-angiogenic drugs and immunecheckpoint inhibitors.

Scientific Advances in Thoracic Oncology 2016

Lung cancer care is rapidly changing with advances in genomic testing, the development of next-generation targeted kinase inhibitors, and the continued broad study of immunotherapy in new settings and potential combinations. The International Association for the Study of Lung Cancer and the Journal of Thoracic Oncology publish this annual update to help readers keep pace with these important developments. Experts in thoracic cancer and care provide focused updates across multiple areas, including prevention and early detection, molecular diagnostics, pathology and staging, surgery, adjuvant therapy, radiotherapy, molecular targeted therapy, and immunotherapy for NSCLC, SCLC, and mesothelioma. Quality and value of care and perspectives on the future of lung cancer research and treatment have also been included in this concise review.

Evaluation of digital PCR for detecting low-level EGFR mutations in advanced lung adenocarcinoma patients: a cross-platform comparison study

Emerging evidence has indicated that circulating tumor DNA (ctDNA) from plasma could be used to analyze EGFR mutation status for NSCLC patients; however, due to the low level of ctDNA in plasma, highly sensitive approaches are required to detect low frequency mutations. In addition, the cutoff for the mutation abundance that can be detected in tumor tissue but cannot be detected in matched ctDNA is still unknown. To assess a highly sensitive method, we evaluated the use of digital PCR in the detection of EGFR mutations in tumor tissue from 47 advanced lung adenocarcinoma patients through comparison with NGS and ARMS. We determined the degree of concordance between tumor tissue DNA and paired ctDNA and analyzed the mutation abundance relationship between them. Digital PCR and Proton had a high sensitivity (96.00% vs. 100%) compared with that of ARMS in the detection of mutations in tumor tissue. Digital PCR outperformed Proton in identifying more low abundance mutations. The ctDNA detection rate of digital PCR was 87.50% in paired tumor tissue with a mutation abundance above 5% and 7.59% in paired tumor tissue with a mutation abundance below 5%. When the DNA mutation abundance of tumor tissue was above 3.81%, it could identify mutations in paired ctDNA with a high sensitivity. Digital PCR will help identify alternative methods for detecting low abundance mutations in tumor tissue DNA and plasma ctDNA.

Osimertinib in patients with advanced epidermal growth factor receptor T790M mutation-positive non-small cell lung cancer: rationale, evidence and place in therapy

The identification of epidermal growth factor receptor (EGFR) mutations represented a fundamental step forward in the treatment of advanced non-small cell lung cancer (NSCLC) as they define a subset of patients who benefit from the administration of specifically designed targeted therapies. The inhibition of mutant EGFR through EGFR-tyrosine kinase inhibitors (TKIs), either reversible, first-generation gefitinib and erlotinib, or irreversible, second-generation afatinib, has dramatically improved the prognosis of patients harboring this specific genetic alteration, leading to unexpected clinical benefit. Unfortunately, virtually all patients who initially respond to treatment develop acquired resistance to EGFR-TKIs within 9-14 months. The EGFR T790M secondary mutation has emerged as a cause of treatment failure in approximately 60% of resistant cases. To date, several compounds designed with the aim to overcome T790M-mediated resistance are under clinical investigation. The aim of this review is to discuss emerging data regarding the third-generation EGFR-TKI, osimertinib, for the treatment of EGFR T790M mutant advanced NSCLC.

Third-Generation Tyrosine Kinase Inhibitors Targeting Epidermal Growth Factor Receptor Mutations in Non-Small Cell Lung Cancer

Sensitizing mutations in the epidermal growth factor receptor (EGFR) predict response to EGFR tyrosine kinase inhibitors (TKIs) and both first- and second-generation TKIs are available as first-line treatment options in patients with advanced EGFR-mutant non-small cell lung cancer. Eventual resistance develops with multiple mechanisms identifiable both upon repeat biopsy and in plasma circulating tumor DNA. The T790M gatekeeper mutation is responsible for almost 60% of cases. A number of third-generation TKIs are in clinical development, and osimertinib has been approved by the US Food and Drug Administration for the treatment of patients with EGFR T790M mutant lung cancer after failure of initial EGFR kinase therapy. Resistance mechanisms are being identified to these novel agents, and the treatment landscape of EGFR-mutant lung cancer continues to evolve. The sequence of EGFR TKIs may change in the future and combination therapies targeting resistance appear highly promising.

Osimertinib: A third-generation tyrosine kinase inhibitor for treatment of epidermal growth factor receptor-mutated non-small cell lung cancer with the acquired Thr790Met mutation

Osimertinib is a third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) approved for the treatment of metastatic EGFR T790M mutation-positive non-small cell lung cancer (NSCLC) in patients failing previous TKI therapy. The T790M mutation is an acquired resistance mechanism found in over half of patients with NSCLC progressing on first-generation TKIs. First- and second-generation TKIs do not inhibit the T790M mutation at clinically relevant concentrations. Osimertinib is selective for mutated forms of EGFR, including the TKI-sensitizing mutations L858R and exon 19 deletions, as well as the acquired T790M resistance mutation. In a trial comparing osimertinib to platinum doublet therapy among patients with the T790M mutation progressing on first-line TKI therapy, median progression-free survival was significantly longer in patients receiving osimertinib. Osimertinib has a favorable safety profile compared to platinum-doublet chemotherapy. Common adverse events include diarrhea, skin rash, dry skin, and paronychia; however, because it spares wild-type EGFR, these toxicities appear to occur with less frequency and severity compared to other TKIs. Serious, but rare, adverse events include pneumonitis, interstitial lung disease-like events, QT interval prolongation, and reduced ejection fraction. Osimertinib has the unique ability to distribute readily into brain tissue compared with other TKIs, giving it a potential role in the treatment and/or prevention of CNS metastases; future studies are warranted in this area. An ongoing study evaluating osimertinib versus first-generation TKIs as first-line treatment for patients with EGFR mutation-positive NSCLC may help to define the role of osimertinib as front-line therapy.

EGFR Mutation Analysis for Prospective Patient Selection in Two Phase II Registration Studies of Osimertinib

INTRODUCTION

Osimertinib is an oral, central nervous system-active, EGFR tyrosine kinase inhibitor (TKI) for the treatment of EGFR T790M-positive advanced NSCLC. Here we have evaluated EGFR mutation frequencies in two phase II studies of osimertinib (AURA extension and AURA2).

METHODS

After progression while receiving their latest line of therapy, patients with EGFR mutation-positive advanced NSCLC provided tumor samples for mandatory central T790M testing for the study selection criteria. Tumor tissue mutation analysis for patient selection was performed with the Roche cobas EGFR Mutation Test (European Conformity-in vitro diagnostic, labeled investigational use only) (Roche Molecular Systems, Pleasanton, CA). Patients should not have been prescreened for T790M mutation status. The cobas test results were compared with those of the MiSeq next-generation sequencing system (Illumina, San Diego, CA), which was used as a reference method.

RESULTS

Samples from 324 and 373 patients screened for AURA extension and AURA2, respectively, produced valid cobas test results. The T790M detection rates were similar between AURA extension and AURA2 (64% and 63%, respectively). The pooled T790M rate was 63%, with no difference by ethnicity (63% for Asian and non-Asian patients alike) or immediately prior treatment with an EGFR TKI (afatinib, 69%; erlotinib, 69%; and gefitinib, 63%). A higher proportion of patients had T790M detected against a background of exon 19 deletions versus L858R mutation (73% versus 58% [p = 0.0002]). In both trials the cobas test demonstrated high sensitivity (positive percent agreement) and specificity (negative percent agreement) for T790M detection when compared with the next-generation sequencing reference method: positive percent agreement of 91% versus 89% and negative percent agreement of 97% versus 98%.

CONCLUSIONS

In both trials, the rate of detection of T790M mutation in patients with advanced NSCLC was approximately 63% and was unaffected by immediately prior treatment with an EGFR TKI or ethnicity.

Optimal management of EGFR-mutant non-small cell lung cancer with disease progression on first-line tyrosine kinase inhibitor therapy

The first-generation epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs), gefitinib and erlotinib, and the second-generation EGFR-TKI, afatinib, have all been approved as standard first-line treatments for advanced EGFR-mutant non-small cell lung cancer (NSCLC) based on superior progression-free survival results compared to platinum doublet chemotherapy regimens. Acquired resistance to an EGFR-TKI inevitably develops after a period of effective drug treatment. After tumor progression, many combination therapy regimens that include an EGFR-TKI, or EGFR-TKI monotherapy, have been tested in prospective trials with the aim of extending survival. Third-generation EGFR-TKIs such as osimertinib have been developed with the aim of overcoming the effects of EGFR T790M resistance mutation, which occurs in half of the patients with disease progression on EGFR-TKI therapy. Osimertinib has become the standard treatment in patients for whom tumor re-biopsy reveals an acquired EGFR T790M mutation following EGFR-TKI therapy. Other third-generation EGFR-TKIs, such as olmutinib, EGF816, and ASP8273, are still in the trial phase.

Plasma ctDNA Analysis for Detection of the EGFR T790M Mutation in Patients with Advanced Non-Small Cell Lung Cancer

INTRODUCTION

Tumor biopsies for detecting EGFR mutations in advanced NSCLC are invasive, costly, and not always feasible for patients with late-stage disease. The clinical utility of the cobas EGFR Mutation Test v2 (Roche Molecular Systems, Inc., Pleasanton, CA) with plasma samples from patients with NSCLC at disease progression after previous EGFR tyrosine kinase inhibitor therapy was investigated to determine eligibility for osimertinib treatment.

METHODS

Matched tumor tissue and plasma samples from patients screened for the AURA extension and AURA2 phase II studies were tested for EGFR mutations by using tissue- and plasma-based cobas EGFR mutation tests. Plasma test performance was assessed by using the cobas tissue test and a next-generation sequencing method (MiSeq [Illumina Inc., San Diego, CA]) as references. The objective response rate, measured by blinded independent central review, was assessed in patients receiving osimertinib with a plasma T790M mutation-positive status.

RESULTS

During screening, 551 patients provided matched tumor tissue and plasma samples. Pooled analysis of the positive and negative percent agreements between the cobas plasma and tissue tests for detection of T790M mutation were 61% and 79%, respectively. Comparing cobas plasma test with next-generation sequencing demonstrated positive and negative percent agreements of 90% or higher. The objective response rate was 64% (95% confidence interval: 57-70) in T790M mutation-positive patients by both cobas tissue and plasma tests (evaluable for response).

CONCLUSIONS

The cobas plasma test detected the T790M mutation in 61% of tumor tissue T790M mutation-positive patients. To mitigate the risk of false-negative plasma results, patients with a negative plasma result should undergo a tissue test where feasible.

[Research Progress of Targeted Therapy for EGFR Gene in Non-small Cell Lung Cancer]

人表皮生长因子受体酪氨酸激酶抑制剂（epidermal growth factor receptor tyrosine kinase inhibitors, EGFR-TKIs）给EGFR基因敏感突变患者带来巨大的临床获益。随着临床和基础研究的不断深入，EGFR-TKI已经越来越受到关注。本综述旨在将2016年EGFR-TKI药物研究进展进行概述。

[Current Status and Prospect of T790M Mutation in Non-small Cell Lung Cancer]

目前，针对表皮生长因子受体（epidermal growth factor receptor, EGFR）突变的非小细胞肺癌（non-small cell lung cancer, NSCLC）公认的一线治疗方案是以EGFR酪氨酸激酶抑制剂（tyrosine kinase inhibitors, TKIs）为主的靶向治疗，尽管一代、二代TKIs带来的靶向治疗可为患者带来更长的无进展生存（progression-free survival, PFS），及更好的耐受，但其远期治疗不可避免会出现耐药。其中，50%以上的获得性耐药与T790M突变有关，因此美国国立综合癌症网络（National Comprehensive Cancer Network, NCCN）推出的最新指南已经提出三代TKI（Osimertinib，奥西替尼）可用于一线TKI治疗进展同时检出T790M突变的患者。但就在三代TKI为我们带来令人鼓舞的可长达13个月的中位PFS及延续着后EGFR-TKIs治疗时代的同时，也面临着严峻的挑战，如怎样实现T790M的检测及动态监测、对已有三代TKI的研究进展、出现三代TKI耐药的机制及后续治疗等，本文将围绕以上各热点问题展开综述。

Current Treatment Algorithms for Patients with Metastatic Non-Small Cell, Non-Squamous Lung Cancer

The treatment paradigm for metastatic non-small cell, non-squamous lung cancer is continuously evolving due to new treatment options and our increasing knowledge of molecular signal pathways. As a result of treatments becoming more efficacious and more personalized, survival for selected groups of non-small cell lung cancer (NSCLC) patients is increasing. In this paper, three algorithms will be presented for treating patients with metastatic non-squamous, NSCLC. These include treatment algorithms for NSCLC patients whose tumors have EGFR mutations, ALK rearrangements, or wild-type/wild-type tumors. As the world of immunotherapy continues to evolve quickly, a future algorithm will also be presented.

Developments in pharmacotherapy for treating metastatic non-small cell lung cancer

INTRODUCTION

Most patients with non-small cell lung (NSCLC), including squamous cell carcinoma, adenocarcinoma and large cell carcinoma, have advanced disease at diagnosis and systemic therapy is the standard-of-care. About 20% of Caucasian patients are affected by an oncogene-addicted advanced NSCLC for which correspondent inhibitors are available. Areas covered: The main state-of-the-art synthetic anticancer drugs in the groups of chemotherapeutics, epidermal growth factor receptor and anaplastic lymphoma kinase tyrosine kinase inhibitors for NSCLC treatment, are reviewed and discussed from phase III randomized practice-changing trials onwards. A structured search of bibliographic databases for peer-reviewed research literature and of main meetings using a focused review question was undertaken. Expert opinion: The survival of NSCLC patients is increasing, regardless of the presence or not of a specific target, due to the availability of new generation drugs. The continuous deep knowledge of the mechanisms of NSCLC development and the constant research into new drugs should lead to the discovery of new potential targets and the synthesis of corresponding inhibitors to improve the outcomes of each subgroup of patients in order to control the disease in a constantly growing percentage of patients.

Treatment in EGFR-mutated Non-small Cell Lung Cancer: How to Block the Receptor and overcome Resistance Mechanisms

In non-small cell lung cancer (NSCLC), the identification of epidermal growth factor receptor (EGFR) mutations and the parallel development of EGFR tyrosine kinase inhibitors (TKIs) have radically changed the therapeutic management strategies. Currently, erlotinib, gefitinib, and afatinib are all approved as standard first-line treatment in EGFR-mutated NSCLC. However, despite the proven efficacy, some EGFR-mutated NSCLCs do not respond to EGFR TKIs, while some patients, after a favorable and prolonged response to EGFR TKIs, inevitably progress within about 10-14 months. Epidermal growth factor receptor-dependent mechanisms, activation of alternative pathways, or phenotypic transformation can cause the resistance to EGFR TKIs. The exon 20 p.Thr790Met point mutation (T790M) is responsible for about 60% of cases of resistance when progression occurs. A third-generation TKI, osimertinib, improved outcome in patients harboring T790M after first- and second-generation TKI treatment. However, resistance develops even after treatment with third-generation drugs. To date, the Cys797Ser (C797S) mutation in exon 20 of EGFR is the most well-known resistance mutation after osimertinib. Fourth-generation TKIs are already under development. Nevertheless, additional information is needed to better understand and effectively overcome resistance. The aim of this review is to report recent advances and future perspectives in the treatment of EGFR-mutated NSCLC, highlighting the resistance mechanisms that underlie disease progression.

Mechanisms of Resistance to Target Therapies in Non-small Cell Lung Cancer

Targeted therapies are revolutionizing the treatment of advanced non-small cell lung cancer (NSCLC). The discovery of key oncogenic events mainly in lung adenocarcinoma, like EGFR mutations or ALK rearrangements, has changed the treatment landscape while improving the prognosis of lung cancer patients. Inevitably, virtually all patients initially treated with targeted therapies develop resistance because of the emergence of an insensitive cellular population, selected by pharmacologic pressure. Diverse mechanisms of resistance, in particular to EGFR, ALK and ROS1 tyrosine-kinase inhibitors (TKIs), have now been discovered and may be classified in three different groups: (1) alterations in the target (such as EGFR T790M and ALK or ROS1 mutations); (2) activation of alternative pathways (i.e. MET amplification, KRAS mutations); (3) phenotype transformation (to small cell lung cancer, epithelial-mesenchymal transition). These basic mechanisms are informing the development of novel therapeutic strategies to overcome resistance in the clinic. Novel-generation molecules include osimertinib, for EGFR-T790M-positive patients, and new ALK-TKIs. Nevertheless, the possible concomitant presence of multiple resistance mechanisms, as well as their heterogeneity among cells and disease localizations, makes research in this field particularly arduous. In this chapter, available evidence and perspectives concerning precise mechanisms of escape to pharmacological inhibition in oncogene-addicted NSCLC are reported for single targets, including but not limited to EGFR and ALK.

Concomitant T790M mutation and small-cell lung cancer transformation after acquired resistance to epidermal growth factor receptor-tyrosine kinase inhibitor

A 70‐year‐old man was admitted to our hospital with an abnormal chest X‐ray shadow. Bronchoscopy revealed an adenocarcinoma tumour with an epidermal growth factor receptor (EGFR) exon 19 deletion. Positron emission tomography–computed tomography scanning and magnetic resonance imaging showed advanced stage IV lung cancer. He was treated with erlotinib as a first‐line drug, which maintained a clinical response for 16 months. After disease progression, a re‐biopsy was done from the tumour in the right lower lobe. The obtained specimen harboured both small‐cell lung cancer (SCLC) transformation with retention of the EGFR 19 deletion and the development of an EGFR T790M mutation. We came across a very rare condition of concomitant T790M mutation and SCLC transformation after acquired resistance to EGFR‐tyrosine kinase inhibitor.