Tissue and Plasma EGFR Mutation Analysis in the FLAURA Trial: Osimertinib versus Comparator EGFR Tyrosine Kinase Inhibitor as First-Line Treatment in Patients with EGFR-Mutated Advanced Non-Small Cell Lung Cancer

Clinical Validity of Plasma-Based Genotyping for Microsatellite Instability Assessment in Advanced GI Cancers: SCRUM-Japan GOZILA Substudy

PURPOSE

Circulating tumor DNA (ctDNA) genotyping may guide targeted therapy for patients with advanced GI cancers. However, no studies have validated ctDNA genotyping for microsatellite instability (MSI) assessment in comparison with a tissue-based standard.

PATIENTS AND METHODS

The performance of plasma-based MSI assessment using Guardant360, a next-generation sequencing–based ctDNA assay, was compared with that of tissue-based MSI assessment using a validated polymerase chain reaction–based method in patients with advanced GI cancers enrolled in GOZILA study, a nationwide ctDNA profiling study. The primary end points were overall percent agreement, positive percent agreement (PPA), and negative percent agreement. The efficacy of immune checkpoint inhibitor therapy was also evaluated.

RESULTS

In 658 patients with advanced GI cancers who underwent both plasma and tissue testing for MSI, the overall percent agreement, PPA, and negative percent agreement were 98.2% (95% CI, 96.8 to 99.1), 71.4% (95% CI, 47.8 to 88.7), and 99.1% (95% CI, 98.0 to 99.7), respectively. In patients whose plasma samples had a ctDNA fraction ≥ 1.0%, the PPA was 100.0% (15/15; 95% CI, 78.2 to 100.0). Three patients with MSI-high (MSI-H) tumors detected only by ctDNA genotyping achieved clinical benefits after receiving anti–programmed cell death 1 therapy with the progression-free survival ranging from 4.3 to 16.7 months. One patient with an aggressive cancer of an unknown primary site benefited from pembrolizumab after rapid detection of MSI-H by ctDNA genotyping.

CONCLUSION

ctDNA genotyping was able to detect MSI with high concordance to validated tissue-based MSI testing, especially in patients with tumors that have sufficient ctDNA shedding. Furthermore, ctDNA genotyping enabled identification of patients with MSI-H tumors who benefited from immune checkpoint inhibitor treatment.

Monitoring of the presence of EGFR-mutated DNA during EGFR-targeted therapy may assist in the prediction of treatment outcome

The aim of our trial was to evaluate the prognostic significance of qualitative ctDNA analysis on different stages of EGFR mutated non-small cell lung cancer (NSCLC) treatment. We included 99 patients amendable for the first line treatment with either gefitinib/erlotinib (n = 87), afatinib (n = 10) or osimertinib (n = 2). Sequential qualitative analysis of ctDNA with cobas® EGFR Mutation Test v2 were performed before first dose, after 2 and 4 months of treatment, and on progression. Our analysis showed clinically significant heterogeneity of EGFR-mutated NSCLC treated with 1st line tyrosine kinase inhibitors (TKIs) in terms of progression-free and overall survival. When treated with conventional approach, i.e. monotherapy with TKIs, the patients falls into three subgroups based on ctDNA analysis before and after 2 months of treatment. Patients without detectable ctDNA at baseline (N = 32) possess the best prognosis on duration of treatment (PFS: 24.07 [16.8-31.3] and OS: 56.2 [21.8-90.7] months). Those who achieve clearance after two months of TKI (N = 42) have indistinguishably good PFS (19.0 [13.7 - 24.2]). Individuals who retain ctDNA after 2 months (N = 25) have the worst prognosis (PFS: 10.3 [7.0 - 13.5], p = 0.000). 9/25 patients did not develop ctDNA clearance at 4 months with no statistical difference in PFS from those without clearance at 2 months. Prognostic heterogeneity of EGFR-mutated NSCLC should be taken into consideration in planning further clinical trials and optimizing the outcome of patients.

Classification and regression tree for estimating predictive markers to detect T790M mutations after acquired resistance to first line EGFR-TKI: HOPE-002

BACKGROUND AND OBJECTIVE

Osimertinib as first-line treatment for patients with non-small cell lung cancer (NSCLC) harboring epidermal growth factor (EGFR) mutations remains controversial. Sequential EGFR-tyrosine kinase inhibitor (TKI) might be superior to the first line osimertinib in patients at risk of developing acquired T790M mutations.

METHODS

We enrolled consecutive patients with EGFR-mutated (deletion 19 or L858R) advanced NSCLC treated with first-line drugs and evaluated predictive markers using classification and regression tree (CART) for the detection of T790M mutations based on patient backgrounds prior to initial treatment.

RESULTS

Patients without acquired T790M mutations had worse outcomes than those with T790M mutations (median OS: 798 days vs. not reached; HR: 2.70; P < 0.001). CART identified three distinct groups based on variables associated with acquired T790M mutations (age, CYF, WBC, liver metastasis, and LDH; AUROC: 0.77). Based on certain variables, CART identified three distinct groups in deletion 19 (albumin, LDH, bone metastasis, pleural effusion, and WBC; AUROC: 0.81) and two distinct groups in L858R (age, CEA, and ALP; AUROC: 0.80). The T790M detection frequencies after TKI resistance of afatinib and first-generation EGFR-TKIs were similar (35.3% vs. 37.4%, P = 0.933). Afatinib demonstrated longer PFS (398 vs. 279 days; HR: 0.67; P = 0.004) and OS (1053 vs. 956 days; HR: 0.68; P = 0.051) than first-generation EGFR-TKIs.

CONCLUSION

Identification of patients at risk of acquiring T790M mutations after EGFR-TKI failure may aid in choice of first-line EGFR-TKI. Furthermore, afatinib may be the more effective 1st-line EGFR-TKI treatment for patients at risk of developing T790M as initial EGFR-TKI resistance.

Use of Circulating Tumour DNA (ctDNA) for Measurement of Therapy Predictive Biomarkers in Patients with Cancer

Biomarkers that predict likely response or resistance to specific therapies are critical in personalising treatment for cancer patients. Such biomarkers are now available for an increasing number of anti-cancer therapies, especially targeted therapy and immunotherapy. The gold-standard method for determining predictive biomarkers requires tumour tissue. Obtaining tissue, however, is not always possible and even if possible, the amount or quality of tissue obtained may be inadequate for biomarker analysis. Tumour DNA, however, can be released into the bloodstream, giving rise to what is referred to as circulating tumour DNA (ctDNA). In contrast to tissue, blood can be obtained from effectively all patients in a minimally invasive and safe manner. Other advantages of blood over tissue for biomarker testing include a shorter turn-around time and an ability to perform serial measurements. Furthermore, blood should provide a more complete profile of mutations present in heterogeneous tumours than a single-needle tissue biopsy. A limitation of blood vis-à-vis tissue, however, is lower sensitivity and, thus, the possibility of missing an actionable mutation. Despite this limitation, blood-based predictive biomarkers, such as mutant EGFR for predicting response to EGFR tyrosine kinase inhibitors in advanced non-small-cell lung cancer and mutant PIK3CA for predicting response to alpelisib in combination with fulvestrant in advanced breast cancer, may be used when tissue is unavailable. Although tissue remains the gold standard for detecting predictive biomarkers, it is likely that several further blood-based assays will soon be validated and used when tissue is unavailable or unsuitable for analysis.

Prognostic Role of Soluble Programmed Death Ligand 1 in Non-Small Cell Lung Cancer: A Systematic Review and Meta-Analysis

OBJECTIVE

The objective of this study was to explore whether soluble programmed death ligand 1 (sPD-L1) is a potential prognostic biomarker in patients with non-small cell lung cancer (NSCLC).

METHODS

A comprehensive search of electronic databases was carried out. Original studies with inclusion of sPD-L1, progression-free survival, and overall survival in NSCLC were eligible. The primary endpoints were overall survival and progression-free survival. Hazard ratios (HRs) and 95% confidence intervals (CIs) were applied for data analysis.

RESULTS

Eight studies involving 710 patients with NSCLC were included in the analysis. A pooled data analysis revealed that high levels of sPD-L1 were correlated with poorer overall survival (HR = 2.34; 95% CI = 1.82-3.00; P < 0.001) and progression-free survival (HR = 2.35; 95% CI = 1.62-3.40, P < 0.001). A subgroup analysis revealed that high levels of sPD-L1 were correlated with poor overall survival in patients treated with immunotherapy (HR = 2.40; 95% CI = 1.79-3.22; P < 0.001).

CONCLUSION

This pooled analysis of published data suggests that sPD-L1 may serve as a readily available biomarker for survival in NSCLC patients treated with ICI based treatment. Prospective studies with well-designed standard assessment methods should be conducted to validate the prognostic role of sPD-L1 in NSCLC.

SYSTEMATIC REVIEW REGISTRATION

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021283177.

The value of cell-free circulating tumour DNA profiling in advanced non-small cell lung cancer (NSCLC) management

Liquid biopsy (LB) has boosted a remarkable change in the management of cancer patients by contributing to tumour genomic profiling. Plasma circulating cell-free tumour DNA (ctDNA) is the most widely searched tumour-related element for clinical application. Specifically, for patients with lung cancer, LB has revealed valuable to detect the diversity of targetable genomic alterations and to detect and monitor the emergence of resistance mechanisms. Furthermore, its non-invasive nature helps to overcome the difficulty in obtaining tissue samples, offering a comprehensive view about tumour diversity. However, the use of the LB to support diagnostic and therapeutic decisions still needs further clarification. In this sense, this review aims to provide a critical view of the clinical importance of plasma ctDNA analysis, the most widely applied LB, and its limitations while anticipating concepts that will intersect the present and future of LB in non-small cell lung cancer patients.

Graphical Abstract

Comparison of solid tissue sequencing and liquid biopsy accuracy in identification of clinically relevant gene mutations and rearrangements in lung adenocarcinomas

Screening for therapeutic targets is standard of care in the management of advanced non-small cell lung cancer. However, most molecular assays utilize tumor tissue, which may not always be available. "Liquid biopsies" are plasma-based next generation sequencing (NGS) assays that use circulating tumor DNA to identify relevant targets. To compare the sensitivity, specificity, and accuracy of a plasma-based NGS assay to solid-tumor-based NGS we retrospectively analyzed sequencing results of 100 sequential patients with lung adenocarcinoma at our institution who had received concurrent testing with both a solid-tissue-based NGS assay and a commercially available plasma-based NGS assay. Patients represented both new diagnoses (79%) and disease progression on treatment (21%); the majority (83%) had stage IV disease. Tissue-NGS identified 74 clinically relevant mutations, including 52 therapeutic targets, a sensitivity of 94.8%, while plasma-NGS identified 41 clinically relevant mutations, a sensitivity of 52.6% (p < 0.001). Tissue-NGS showed significantly higher sensitivity and accuracy across multiple patient subgroups, both in newly diagnosed and treated patients, as well as in metastatic and nonmetastatic disease. Discrepant cases involved hotspot mutations and actionable fusions including those in EGFR, ALK, and NTRK1. In summary, tissue-NGS detects significantly more clinically relevant alterations and therapeutic targets compared to plasma-NGS, suggesting that tissue-NGS should be the preferred method for molecular testing of lung adenocarcinoma when tissue is available. Plasma-NGS can still play an important role when tissue testing is not possible. However, given its low sensitivity, a negative result should be confirmed with a tissue-based assay.

Liquid Biopsy for Advanced NSCLC: A Consensus Statement From the International Association for the Study of Lung Cancer

Although precision medicine has had a mixed impact on the clinical management of patients with advanced-stage cancer overall, for NSCLC, and more specifically for lung adenocarcinoma, the advances have been dramatic, largely owing to the genomic complexity and growing number of druggable oncogene drivers. Furthermore, although tumor tissue is historically the "accepted standard" biospecimen for these molecular analyses, there are considerable innate limitations. Thus, liquid biopsy represents a practical alternative source for investigating tumor-derived somatic alterations. Although data are most robust in NSCLC, patients with other cancer types may also benefit from this minimally invasive approach to facilitate selection of targeted therapies. The liquid biopsy approach includes a variety of methodologies for circulating analytes. From a clinical point of view, plasma circulating tumor DNA is the most extensively studied and widely adopted alternative to tissue tumor genotyping in solid tumors, including NSCLC, first entering clinical practice for detection of EGFR mutations in NSCLC. Since the publication of the first International Association for the Study of Lung Cancer (IASLC) liquid biopsy statement in 2018, several additional advances have been made in this field, leading to changes in the therapeutic decision-making algorithm for advanced NSCLC and prompting this 2021 update. In view of the novel and impressive technological advances made in the past few years, the growing clinical application of plasma-based, next-generation sequencing, and the recent Food and Drug and Administration approval in the United States of two different assays for circulating tumor DNA analysis, IASLC revisited the role of liquid biopsy in therapeutic decision-making in a recent workshop in October 2020 and the question of "plasma first" versus "tissue first" approach toward molecular testing for advanced NSCLC. Moreover, evidence-based recommendations from IASLC provide an international perspective on when to order which test and how to interpret the results. Here, we present updates and additional considerations to the previous statement article as a consensus from a multidisciplinary and international team of experts selected by IASLC.

Molecular Mechanism of EGFR-TKI Resistance in EGFR-Mutated Non-Small Cell Lung Cancer: Application to Biological Diagnostic and Monitoring

Non-small cell lung cancer (NSCLC) is the most common cancer in the world. Activating epidermal growth factor receptor (EGFR) gene mutations are a positive predictive factor for EGFR tyrosine kinase inhibitors (TKIs). For common EGFR mutations (Del19, L858R), the standard first-line treatment is actually third-generation TKI, osimertinib. In the case of first-line treatment by first (erlotinib, gefitinib)- or second-generation (afatinib) TKIs, osimertinib is approved in second-line treatment for patients with T790M EGFR mutation. Despite the excellent disease control results with EGFR TKIs, acquired resistance inevitably occurs and remains a biological challenge. This leads to the discovery of novel biomarkers and possible drug targets, which vary among the generation/line of EGFR TKIs. Besides EGFR second/third mutations, alternative mechanisms could be involved, such as gene amplification or gene fusion, which could be detected by different molecular techniques on different types of biological samples. Histological transformation is another mechanism of resistance with some biological predictive factors that needs tumor biopsy. The place of liquid biopsy also depends on the generation/line of EGFR TKIs and should be a good candidate for molecular monitoring. This article is based on the literature and proposes actual and future directions in clinical and translational research.

Osimertinib: A Review in Previously Untreated, EGFR Mutation-Positive, Advanced NSCLC

Activating mutations in the epidermal growth factor receptor (EGFR) gene have been identified as key oncogenic drivers of non-small cell lung cancer (NSCLC). Osimertinib (Tagrisso^®) is an orally administered, third-generation EGFR tyrosine kinase inhibitor (EGFR-TKI) that is widely approved for the first-line treatment of advanced NSCLC with activating EGFR mutations. In the pivotal phase III FLAURA trial, osimertinib significantly prolonged progression-free survival (PFS) and overall survival (OS) relative to first-generation EGFR-TKIs in patients with previously untreated, EGFR mutation-positive, advanced NSCLC. Osimertinib also significantly prolonged central nervous system (CNS) PFS in patients with CNS metastases at trial entry. Osimertinib had a generally manageable tolerability profile; the majority of adverse events considered to be possibly related to treatment were of mild to moderate severity. Osimertinib represents a valuable targeted therapeutic for use in adults with previously untreated, EGFR mutation-positive, advanced NSCLC.

The Combiome Hypothesis: Selecting Optimal Treatment for Cancer Patients

Existing approaches for cancer diagnosis are inefficient in the use of diagnostic tissue, and decision-making is often sequential, typically resulting in delayed treatment initiation. Future diagnostic testing needs to be faster and optimize increasingly complex treatment decisions. We envision a future where comprehensive testing is routine. Our approach, termed the "combiome," combines holistic information from the tumor, and the patient's immune system. The combiome model proposed here advocates synchronized up-front testing with a panel of sensitive assays, revealing a more complete understanding of the patient phenotype and improved targeting and sequencing of treatments. Development and eventual adoption of the combiome model for diagnostic testing may provide better outcomes for all cancer patients, but will require significant changes in workflows, technology, regulations, and administration. In this review, we discuss the current and future testing landscape, targeting of personalized treatments, and technological and regulatory advances necessary to achieve the combiome.

EGFR-plasma mutations in prognosis for non-small cell lung cancer treated with EGFR TKIs: A meta-analysis

BACKGROUND

The plasma-based epidermal growth factor receptor (EGFR) mutation testing is approved recently to use in clinical practice. However, it has not been used as a prognostic marker yet because of contradictory results.

AIM

This meta-analysis aims to clarify the role of the EGFR-plasma test in prognosis for non-small cell lung cancer (NSCLC) who have mutant tumors and receive EGFR tyrosine kinase inhibitors (TKIs).

METHODS AND RESULTS

The PubMed/MEDLINE, Web of Science, Cochrane Library, and Google Scholar databases were searched for relevant studies by April 10, 2021. The hazard ratio (HR) from reports was extracted and used to assess the correlation of EGFR-plasma status with progression-free survival (PFS) and overall survival (OS). A total of 35 eligible studies with 4106 patients were enrolled in the final analysis. Patients with concurrent EGFR mutations in pretreatment plasma have shorter PFS (HR = 2.00, 95% confidence interval [CI]: 1.73-2.31, p < .001) and OS time (HR = 2.31, 95% CI: 1.89-2.83, p < .001) compared to the tumor-only mutation cases. Besides, the persistence of EGFR-activating mutations in post-treatment plasma is associated with worse PFS (HR = 3.84, 95% CI: 2.96-4.99, p < .001) and OS outcome (HR = 3.22, 95% CI: 2.35-4.42, p < .001) compared to others. Notably, the prognostic value of the EGFR-plasma test is also validated in treatment with third-generation EGFR TKI and significance regardless of different detection methods.

CONCLUSION

The presence of EGFR-plasma mutations at pretreatment and after EGFR TKI initiation is the worse prognostic factor for PFS and OS in NSCLC.

Highly sensitive fusion detection using plasma cell-free RNA in non-small-cell lung cancers

ALK, ROS1, and RET kinase fusions are important predictive biomarkers of tyrosine kinase inhibitors (TKIs) in non‐small‐cell lung cancer (NSCLC). Analysis of cell‐free DNA (cfDNA) provides a noninvasive method to identify gene changes in tumor cells. The present study sought to use cfRNA and cfDNA for identifying fusion genes. A reliable protocol was established to detect fusion genes using cfRNA and assessed the analytical validity and clinical usefulness in 30 samples from 20 cases of fusion‐positive NSCLC. The results of cfRNA‐based assays were compared with tissue biopsy and cfDNA‐based liquid biopsy (Guardant360 plasma next‐generation sequencing [NGS] assay). The overall sensitivity of the cfRNA‐based assay was 26.7% (8/30) and that of cfDNA‐based assay was 16.7% (3/18). When analysis was limited to the samples collected at chemo‐naïve or progressive disease status and available for both assays, the sensitivity of the cfRNA‐based assay was 77.8% (7/9) and that of cfDNA‐based assay was 33.3% (3/9). Fusion gene identification in cfRNA was correlated with treatment response. These results suggest that the proposed cfRNA assay is a useful diagnostic test for patients with insufficient tissues to facilitate effective administration of first‐line treatment and is a useful tool to monitor the progression of NSCLC for consideration of second‐line treatments.

LungBEAM: A prospective multicenter study to monitor stage IV NSCLC patients with EGFR mutations using BEAMing technology

OBJECTIVES

The aim of LungBEAM was to determine the value of a novel epidermal growth factor receptor (EGFR) mutation test in blood based on BEAMing technology to predict disease progression in advanced non-small cell lung cancer (NSCLC) patients treated with first- or second-generation EGFR-tyrosine kinase inhibitors (EGFR-TKIs). Another goal was to monitor the dynamics of EGFR mutations, as well as to track EGFR exon 20 p.T790M (p.T790M) resistance during treatment, as critical indicators of therapeutic efficacy and patient survival.

METHODS

Stage IV NSCLC patients with locally confirmed EGFR-TKI sensitizing mutations (ex19del and/or L858R) in biopsy tissue who were candidates to receive first- or second-generation EGFR-TKI as first-line therapy were included. Plasma samples were obtained at baseline and every 4 weeks during treatment until a progression-free survival (PFS) event or until study completion (72-week follow-up). The mutant allele fraction (MAF) was determined for each identified mutation using BEAMing.

RESULTS

A total of 68 of the 110 (61.8%) patients experienced a PFS event. Twenty-six patients (23.6%) presented with an emergent p.T790M mutation in plasma at some point during follow-up, preceding radiologic progression with a median of 76 (interquartile ratio: 54-111) days. Disease progression correlated with the appearance of p.T790M in plasma with a hazard ratio (HR) of 1.94 (95% confidence interval [CI], 1.48-2.54; p < 0.001). The HR for progression in patients showing increasing plasma sensitizing mutation levels (positive MAF slope) versus patients showing either decreasing or unchanged plasma mutation levels (negative or null MAF slopes) was 3.85 (95% CI, 2.01-7.36; p < 0.001).

CONCLUSION

Detection and quantification of EGFR mutations in circulating tumor DNA using the highly sensitive BEAMing method should greatly assist in optimizing treatment decisions for advanced NSCLC patients.

Update on molecular pathology and role of liquid biopsy in nonsmall cell lung cancer

Personalised medicine, an essential component of modern thoracic oncology, has been evolving continuously ever since the discovery of the epidermal growth factor receptor and its tyrosine kinase inhibitors. Today, screening for driver alterations in patients with advanced lung adenocarcinoma as well as those with squamous cell carcinoma and no/little history of smoking is mandatory. Multiplex molecular platforms are preferred to sequential molecular testing since they are less time- and tissue-consuming. In this review, we present the latest updates on the nine most common actionable driver alterations in nonsmall cell lung cancer. Liquid biopsy, a simple noninvasive technique that uses different analytes, mostly circulating tumour DNA, is an appealing tool that is used in thoracic oncology to identify driver alterations including resistance mutations. Additional roles are being evaluated in clinical trials and include monitoring the response to treatment, screening for lung cancer in high-risk patients and early detection of relapse in the adjuvant setting. In addition, liquid biopsy is being tested in immune-oncology as a prognostic, predictive and pharmacodynamic tool. The major limitation of plasma-based assays remains their low sensitivity when compared to tissue-based assays. Ensuring the clinical validity and utility of liquid biopsy will definitely optimise cancer care.

Screening for driver alterations in patients with advanced lung adenocarcinoma and those with squamous cell carcinoma and no/little smoking history is mandatory. Liquid biopsy is evolving constantly and will definitely improve outcomes in thoracic oncology.https://bit.ly/2XjuQrD

Performance Characteristics of a Real-Time Polymerase Chain Reaction Assay for the Detection of Epidermal Growth Factor Receptor (EGFR) Mutations in Plasma Samples of Non-Small Cell Lung Cancer (NSCLC) Patients

BACKGROUND

Circulating free DNA in plasma is an alternative source of tumor-derived DNA that can be a surrogate for tissue epidermal growth factor receptor (EGFR) testing.

OBJECTIVE

We evaluated the analytical performance of the cobas^® EGFR Mutation Test v2 (cobas test), a real-time polymerase chain reaction assay designed to detect defined EGFR gene mutations in plasma from patients with advanced non-small cell lung cancer (NSCLC).

METHODS

We used K2-ethylenediaminetetraacetic acid plasma samples from NSCLC patients and healthy donors (HDs), along with cell line DNA. Results from a complete technical performance evaluation are described, including a comparison between NSCLC and HD plasma to support the use of surrogate samples and an independent confirmation of the limit of detection (LoD).

RESULTS

The cobas test reported an overall percent agreement of approximately 88% for plasma samples when compared with a next-generation sequencing method. The LoD for all EGFR mutations was ≤ 100 copies/mL for plasma samples. An external study confirmed the LoD for exon 19 deletion, L858R, and T790M at ≤ 100 copies/mL using samples derived from NSCLC patient specimens. The cobas test showed linearity between at least 50 and 10,000 copies/mL for plasma samples. An internal repeatability study reported a correct call accuracy of 99.2% for plasma samples. The performance of the cobas test is equivalent when using sheared or intact cell line DNA diluted into either HD plasma or NSCLC patient plasma.

CONCLUSIONS

The cobas test is a sensitive, robust, and accurate assay that delivers reproducible results.

Longitudinal Circulating Tumor DNA Analysis in Blood and Saliva for Prediction of Response to Osimertinib and Disease Progression in EGFR-Mutant Lung Adenocarcinoma

Background: We assessed whether serial ctDNA monitoring of plasma and saliva predicts response and resistance to osimertinib in EGFR-mutant lung adenocarcinoma. Three ctDNA technologies-blood-based droplet-digital PCR (ddPCR), next-generation sequencing (NGS), and saliva-based EFIRM liquid biopsy (eLB)-were employed to investigate their complementary roles. Methods: Plasma and saliva samples were collected from patients enrolled in a prospective clinical trial of osimertinib and local ablative therapy upon progression (NCT02759835). Plasma was analyzed by ddPCR and NGS. Saliva was analyzed by eLB. Results: A total of 25 patients were included. We analyzed 534 samples by ddPCR (n = 25), 256 samples by NGS (n = 24) and 371 samples by eLB (n = 22). Among 20 patients who progressed, ctDNA progression predated RECIST 1.1 progression by a median of 118 days (range: 61-272 days) in 11 (55%) patients. Of nine patients without ctDNA progression by ddPCR, two patients had an increase in mutant EGFR by eLB and two patients were found to have ctDNA progression by NGS. Levels of ctDNA measured by ddPCR and NGS at early time points, but not volumetric tumor burden, were associated with PFS. EGFR/ERBB2/MET/KRAS amplifications, EGFR C797S, PIK3CA E545K, PTEN V9del, and CTNNB1 S45P were key resistance mechanisms identified by NGS. Conclusion: Serial assessment of ctDNA in plasma and saliva predicts response and resistance to osimertinib, with each assay having supplementary roles.

The evolving paradigm of precision medicine in lung cancer

PURPOSE OF REVIEW

In this review, we report a complete and updated summary of the most recent treatment advances in the fields of oncogene-addicted disease and provide expert perspectives on the evolving paradigm of precision medicine in lung cancer patients.

RECENT FINDINGS

The advent of innovative genome sequencing technologies is rapidly increasing the number of targetable molecular alterations in advanced nonsmall cell lung cancer (NSCLC), leading to the introduction of novel selective inhibitors into the clinical arena, showing unprecedent tumor responses against rare and elusive NSCLC targets. The results of the ADAURA trial suggested that targeting EGFR pathway in the adjuvant setting is a feasible and effective strategy. The routine use of next-generation sequencing (NGS) is currently recommended as new standard approach to profile advanced NSCLC samples while recent findings suggest the potential application of a plasma-based first approach for tumor genotyping. Innovative umbrella trials provide the right infrastructure to investigate the role of precision medicine in advanced NSCLC, but failed to show clinical benefit.

SUMMARY

Implementing NGS-based molecular screening, increasing patients' access to biomarker driven-clinical trials, ensuring equal access to molecular testing and innovative treatments, overcoming disparities and preserve health systems' financial sustainability represents the main challenges of precision medicine worldwide.

Non-Small Cell Lung Cancer Harboring Concurrent EGFR Genomic Alterations: A Systematic Review and Critical Appraisal of the Double Dilemma

The molecular pathways which promote lung cancer cell features have been broadly explored, leading to significant improvement in prognostic and diagnostic strategies. Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) have dramatically altered the treatment approach for patients with metastatic non-small cell lung cancer (NSCLC). Latest investigations by using next-generation sequencing (NGS) have shown that other oncogenic driver mutations, believed mutually exclusive for decades, could coexist in EGFR-mutated NSCLC patients. However, the exact clinical and pathological role of concomitant genomic aberrations needs to be investigated. In this systematic review, we aimed to summarize the recent data on the oncogenic role of concurrent genomic alterations, by specifically evaluating the characteristics, the pathological significance, and their potential impact on the treatment approach.

High Sensitivity of Plasma Cell-Free DNA Genotyping in Cases With Evidence of Adequate Tumor Content

Plasma cell-free DNA (cfDNA) sequencing is a compelling diagnostic tool in solid tumors and has been shown to have high positive predictive value. However, limited assay sensitivity means that negative plasma genotyping, or the absence of detection of mutation of interest, still requires reflex tumor biopsy.

METHODS

We analyzed two independent cohorts of patients with advanced non-small-cell lung cancer (NSCLC) with known canonical driver and resistance mutations who underwent plasma cfDNA genotyping. We measured quantitative features, such as maximum allelic frequency (mAF), as clinically available measures of cfDNA tumor content, and studied their relationship with assay sensitivity.

RESULTS

In patients with EGFR-mutant NSCLC harboring EGFR T790M, detection of driver mutation at > 1% AF conferred a sensitivity of 97% (368/380) for detection of T790M across three cfDNA genotyping platforms. Similarly, in a second cohort of patients with EGFR or KRAS driver mutations, when the mAF of nontarget mutations was > 1%, sensitivity for driver mutation detection was 100% (43/43). Combining the two NSCLC patient cohorts, the presence of nontarget mutations at mAF > 1% predicts for high sensitivity (> 95%) for identifying the presence of the known driver mutation, whereas mAF of ≤ 1% confers sensitivity of only 26%-54% across platforms. Focusing on 21 false-negative cases where the driver mutation was not detected on plasma next-generation sequencing, other mutations (presumably clonal hematopoiesis) were detected at ≤ 1% AF in 14 (67%).

CONCLUSION

Plasma cfDNA genotyping is highly sensitive when adequate tumor DNA content is present. The likelihood of a false-negative cfDNA genotyping result is low in a sample with evidence of > 1% tumor content. Bioinformatic approaches are needed to further optimize the assessment of cfDNA tumor content in plasma genotyping assays.

Collagen modifying enzyme P4HA1 is overexpressed and plays a role in lung adenocarcinoma

Lung cancer is the leading cause of cancer-related deaths globally and is histologically defined as either small cell lung cancer (SCLC) or non-small cell lung cancer (NSCLC), with the latter accounting for 80% of all lung cancers. The 5-year overall survival rate for lung cancer patients is low as it is often discovered at advanced stages when potential cure by surgical resection is no longer an option. To identify a biomarker and target for lung cancer, we performed analysis of multiple datasets of lung cancer gene expression data. Our analyses indicated that the collagen-modifying enzyme Prolyl 4-Hydroxylase Subunit Alpha 1 (P4HA1) is overexpressed in NSCLC. Furthermore, our investigation found that overexpression of enzymes involved in this pathway predicts poor outcome for patients with lung adenocarcinoma. Our functional studies using knockdown strategies in lung cancer cell lines in vitro indicated that P4HA1 is critical for lung cancer growth, migration, and invasion. Additionally, diethyl pythiDC (PythiDC), a small molecule inhibitor, decreased the malignant phenotypes of lung cancer cells. Moreover, we found that miR-124 regulates and targets P4HA1 in lung cancer cells. Thus, our study suggests that collagen-modifying enzymes play an important role in lung cancer aggressiveness. Furthermore, our studies showed that P4HA1 is required for lung cancer cell growth and invasion, suggesting its potential as a valid therapeutic target in lung adenocarcinoma.

Earlier extracranial progression and shorter survival in ALK-rearranged lung cancer with positive liquid rebiopsies

Background

Liquid rebiopsies can detect resistance mutations to guide therapy of anaplastic lymphoma kinase-rearranged (ALK⁺) non-small-cell lung cancer (NSCLC) failing tyrosine kinase inhibitors (TKI). Here, we analyze how their results relate to the anatomical pattern of disease progression and patient outcome.

Methods

Clinical, molecular, and radiologic characteristics of consecutive TKI-treated ALK⁺ NSCLC patients were analyzed using prospectively collected plasma samples and the 17-gene targeted AVENIO kit, which covers oncogenic drivers and all TP53 exons.

Results

In 56 patients, 139 instances of radiologic changes were analyzed, of which 133 corresponded to disease progression. Circulating tumor DNA (ctDNA) alterations were identified in most instances of extracranial progression (58/94 or 62%), especially if concomitant intracranial progression was also present (89%, P<0.001), but rarely in case of isolated central nervous system (CNS) progression (8/39 or 21%, P<0.001). ctDNA detectability correlated with presence of “short” echinoderm microtubule-associated protein-like 4 (EML4)-ALK fusion variants (mainly V3, E6:A20) and/or TP53 mutations (P<0.05), and presented therapeutic opportunities in <50% of cases. Patients with extracranial progression and positive liquid biopsies had shorter survival from the start of palliative treatment (mean 52 vs. 69 months, P=0.002), regardless of previous and subsequent therapy and initial ECOG performance status. Furthermore, for patients with extracranial progression, ctDNA detectability was associated with shorter next-line progression-free survival (PFS) (3 vs. 13 months, P=0.003) if they were switched to another systemic therapy (49/86 samples), and with shorter time-to-next-treatment (TNT) (3 vs. 8 months, P=0.004) if they were continued on the same treatment due to oligoprogression (37/86). In contrast, ctDNA detectability was not associated with the outcome of patients showing CNS-only progression. In 6/6 cases with suspicion of non-neoplastic radiologic lung changes (mainly infection or pneumonitis), ctDNA results remained negative.

Conclusions

Positive blood-based liquid rebiopsies in ALK⁺ NSCLC characterize biologically more aggressive disease and are common with extracranial, but rare with CNS-only progression or benign radiologic changes. These results reconcile the increased detection of ALK resistance mutations with other features of the high-risk EML4-ALK V3-associated phenotype. Conversely, most oligoprogressive patients with negative liquid biopsies have a more indolent course without need for early change of systemic treatment.

Circulating Biomarkers for Early Stage Non-Small Cell Lung Carcinoma Detection: Supplementation to Low-Dose Computed Tomography

Lung cancer is currently the leading cause of cancer death in both developing and developed countries. Given that lung cancer has poor prognosis in later stages, it is essential to achieve an early diagnosis to maximize patients’ overall survival. Non-small cell lung cancer (NSCLC) is the most common form of primary lung cancer in both smokers and non-smokers. The current standard screening method, low‐dose computed tomography (LDCT), is the only radiological method that demonstrates to have mortality benefits across multiple large randomized clinical trials (RCT). However, these RCTs also found LDCT to have a significant false positive rate that results in unnecessary invasive biopsies being performed. Due to the lack of both sensitive and specific screening methods for the early detection of lung cancer, there is an urgent need for alternative minimally or non-invasive biomarkers that may provide diagnostic, and/or prognostic information. This has led to the identification of circulating biomarkers that can be readily detectable in blood and have been extensively studied as prognosis markers. Circulating microRNA (miRNA) in particular has been investigated for these purposes as an augmentation to LDCT, or as direct diagnosis of lung cancer. There is, however, a lack of consensus across the studies on which miRNAs are the most clinically useful. Besides miRNA, other potential circulating biomarkers include circulating tumor cells (CTCs), circulating tumor DNA (ctDNAs) and non-coding RNAs (ncRNAs). In this review, we provide the current outlook of several of these biomarkers for the early diagnosis of NSCLC.

The Promise of Liquid Biopsy to Predict Response to Immunotherapy in Metastatic Melanoma

Metastatic melanoma is the deadliest form of skin cancer whose incidence has been rising dramatically over the last few decades. Nowadays, the most successful approach in treating advanced melanoma is immunotherapy which encompasses the use of immune checkpoint blockers able to unleash the immune system's activity against tumor cells. Immunotherapy has dramatically changed clinical practice by contributing to increasing long term overall survival. Despite these striking therapeutic effects, the clinical benefits are strongly mitigated by innate or acquired resistance. In this context, it is of utmost importance to develop methods capable of predicting patient response to immunotherapy. To this purpose, one major step forward may be provided by measuring non-invasive biomarkers in human fluids, namely Liquid Biopsies (LBs). Several LB approaches have been developed over the last few years thanks to technological breakthroughs that have allowed to evaluate circulating components also when they are present in low abundance. The elements of this so-called "circulome" mostly encompass: tumor DNA, tumor and immune cells, soluble factors and non-coding RNAs. Here, we review the current knowledge of these molecules as predictors of response to immunotherapy in metastatic melanoma and predict that LB will soon enter into routine practice in order to guide clinical decisions for cancer immunotherapy.

Development and Analytical Validation of a Reverse Transcription Droplet Digital PCR (RT-ddPCR) Assay for PD-L1 Transcripts in Circulating Tumor Cells

BACKGROUND

PD-L1, an immune checkpoint protein, is an important biomarker for monitoring cancer patients during the administration of cancer immunotherapy. Droplet digital PCR (ddPCR), is a highly sensitive and accurate tool for the quantification of cancer biomarkers in liquid biopsy. We report the development and analytical validation of a novel duplex RT-ddPCR assay for the simultaneous quantification of PD-L1 and hypoxanthine phosphoribosyltransferase (HPRT) (used as reference gene) transcripts in circulating tumor cells (CTCs).

METHODS

RT-ddPCR experimental conditions were first optimized and the assay was analytically validated using synthetic standards and the BB49 and SCC47 cancer cell lines. The developed assay was further applied in 71 peripheral blood (PB) samples from head and neck squamous cell carcinoma (HNSCC) patients and 20 PB samples from healthy donors. PD-L1 and HPRT transcripts were quantified in cDNAs derived from CTCs isolated by a size-dependent microfluidic device. The developed RT-ddPCR assay was directly compared to RT-qPCR using 71 identical patient cDNA samples.

RESULTS

Analytical sensitivity was 0.64 copies/μL, while estimation of intra- and interassay variation revealed a high reproducibility (within-run CV%:4.7-23%; between-run CV%:13%). Using the developed RT-ddPCR assay 33/71(46.5%) HNSCC patients' samples were found positive for PD-L1 expression in CTCs, while by using RT-qPCR fewer samples (23/71, 32.4%) were positive (concordance: 55/71, 77.5%).

CONCLUSIONS

The developed RT-ddPCR assay for PD-L1 in CTCs is highly sensitive, specific, and reproducible; additionally, it offers improved diagnostic sensitivity over RT-qPCR. The clinical utility of the assay should be prospectively evaluated for the real-time monitoring of CTCs of cancer patients under immunotherapy.

Treatment of Brain Metastases of Non-Small Cell Lung Carcinoma

Lung cancer is one of the most common malignant neoplasms. As a result of the disease's progression, patients may develop metastases to the central nervous system. The prognosis in this location is unfavorable; untreated metastatic lesions may lead to death within one to two months. Existing therapies-neurosurgery and radiation therapy-do not improve the prognosis for every patient. The discovery of Epidermal Growth Factor Receptor (EGFR)-activating mutations and Anaplastic Lymphoma Kinase (ALK) rearrangements in patients with non-small cell lung adenocarcinoma has allowed for the introduction of small-molecule tyrosine kinase inhibitors to the treatment of advanced-stage patients. The Epidermal Growth Factor Receptor (EGFR) is a transmembrane protein with tyrosine kinase-dependent activity. EGFR is present in membranes of all epithelial cells. In physiological conditions, it plays an important role in the process of cell growth and proliferation. Binding the ligand to the EGFR causes its dimerization and the activation of the intracellular signaling cascade. Signal transduction involves the activation of MAPK, AKT, and JNK, resulting in DNA synthesis and cell proliferation. In cancer cells, binding the ligand to the EGFR also leads to its dimerization and transduction of the signal to the cell interior. It has been demonstrated that activating mutations in the gene for EGFR-exon19 (deletion), L858R point mutation in exon 21, and mutation in exon 20 results in cancer cell proliferation. Continuous stimulation of the receptor inhibits apoptosis, stimulates invasion, intensifies angiogenesis, and facilitates the formation of distant metastases. As a consequence, the cancer progresses. These activating gene mutations for the EGFR are present in 10-20% of lung adenocarcinomas. Approximately 3-7% of patients with lung adenocarcinoma have the echinoderm microtubule-associated protein-like 4 (EML4)/ALK fusion gene. The fusion of the two genes EML4 and ALK results in a fusion gene that activates the intracellular signaling pathway, stimulates the proliferation of tumor cells, and inhibits apoptosis. A new group of drugs-small-molecule tyrosine kinase inhibitors-has been developed; the first generation includes gefitinib and erlotinib and the ALK inhibitor crizotinib. These drugs reversibly block the EGFR by stopping the signal transmission to the cell. The second-generation tyrosine kinase inhibitor (TKI) afatinib or ALK inhibitor alectinib block the receptor irreversibly. Clinical trials with TKI in patients with non-small cell lung adenocarcinoma with central nervous system (CNS) metastases have shown prolonged, progression-free survival, a high percentage of objective responses, and improved quality of life. Resistance to treatment with this group of drugs emerging during TKI therapy is the basis for the detection of resistance mutations. The T790M mutation, present in exon 20 of the EGFR gene, is detected in patients treated with first- and second-generation TKI and is overcome by Osimertinib, a third-generation TKI. The I117N resistance mutation in patients with the ALK mutation treated with alectinib is overcome by ceritinib. In this way, sequential therapy ensures the continuity of treatment. In patients with CNS metastases, attempts are made to simultaneously administer radiation therapy and tyrosine kinase inhibitors. Patients with lung adenocarcinoma with CNS metastases, without activating EGFR mutation and without ALK rearrangement, benefit from immunotherapy. This therapeutic option blocks the PD-1 receptor on the surface of T or B lymphocytes or PD-L1 located on cancer cells with an applicable antibody. Based on clinical trials, pembrolizumab and all antibodies are included in the treatment of non-small cell lung carcinoma with CNS metastases.

Next Generation Sequencing-Based Profiling of Cell Free DNA in Patients with Advanced Non-Small Cell Lung Cancer: Advantages and Pitfalls

Lung cancer (LC) is the main cause of death for cancer worldwide and non-small cell lung cancer (NSCLC) represents the most common histology. The discovery of genomic alterations in driver genes that offer the possibility of therapeutic intervention has completely changed the approach to the diagnosis and therapy of advanced NSCLC patients, and tumor molecular profiling has become mandatory for the choice of the most appropriate therapeutic strategy. However, in approximately 30% of NSCLC patients tumor tissue is inadequate for biomarker analysis. The development of highly sensitive next generation sequencing (NGS) technologies for the analysis of circulating cell-free DNA (cfDNA) is emerging as a valuable alternative to assess tumor molecular landscape in case of tissue unavailability. Additionally, cfDNA NGS testing can better recapitulate NSCLC heterogeneity as compared with tissue testing. In this review we describe the main advantages and limits of using NGS-based cfDNA analysis to guide the therapeutic decision-making process in advanced NSCLC patients, to monitor the response to therapy and to identify mechanisms of resistance early. Therefore, we provide evidence that the implementation of cfDNA NGS testing in clinical research and in the clinical practice can significantly improve precision medicine approaches in patients with advanced NSCLC.

The Role of the Liquid Biopsy in Decision-Making for Patients with Non-Small Cell Lung Cancer

Liquid biopsy is a rapidly emerging tool of precision oncology enabling minimally invasive molecular diagnostics and longitudinal monitoring of treatment response. For the clinical management of advanced stage lung cancer patients, detection and quantification of circulating tumor DNA (ctDNA) is now widely adopted into clinical practice. Still, interpretation of results and validation of ctDNA-based treatment decisions remain challenging. We report here our experience implementing liquid biopsies into the clinical management of lung cancer. We discuss advantages and limitations of distinct ctDNA assay techniques and highlight our approach to the analysis of recurrent molecular alterations found in lung cancer. Moreover, we report three exemplary clinical cases illustrating the complexity of interpreting liquid biopsy results in clinical practice. These cases underscore the potential and current limitations of liquid biopsy, focusing on the difficulty of interpreting discordant findings. In our view, despite all current limitations, the analysis of ctDNA in lung cancer patients is an essential and highly versatile complementary diagnostic tool for the clinical management of lung cancer patients in the era of precision oncology.

Implementing ctDNA Analysis in the Clinic: Challenges and Opportunities in Non-Small Cell Lung Cancer

Tumor genomic profiling has a dramatic impact on the selection of targeted treatment and for the identification of resistance mechanisms at the time of progression. Solid tissue biopsies are sometimes challenging, and liquid biopsies are used as a non-invasive alternative when tissue is limiting. The clinical relevance of tumor genotyping through analysis of ctDNA is now widely recognized at all steps of the clinical evaluation process in metastatic non-small cell lung cancer (NSCLC) patients. ctDNA analysis through liquid biopsy has recently gained increasing attention as well in the management of early and locally advanced, not oncogene-addicted, NSCLC. Its potential applications in early disease detection and the response evaluation to radical treatments are promising. The aim of this review is to summarize the landscape of liquid biopsies in clinical practice and also to provide an overview of the potential perspectives of development focusing on early detection and screening, the assessment of minimal residual disease, and its potential role in predicting response to immunotherapy. In addition to available studies demonstrating the clinical relevance of liquid biopsies, there is a need for standardization and well-designed clinical trials to demonstrate its clinical utility.

Mass Spectrometry as a Highly Sensitive Method for Specific Circulating Tumor DNA Analysis in NSCLC: A Comparison Study

Simple Summary

We compared the UltraSEEK™ Lung Panel on the MassARRAY^® System (Agena Bioscience) with the FDA-approved Cobas^® EGFR Mutation Test v2 for the detection of EGFR mutations in liquid biopsies of NSCLC patients, accompanied with preanalytical sample assessment using the novel Liquid IQ^® Panel. For the detection of relevant predictive mutations using the UltraSEEK™ Lung Panel, an input of over 10 ng showed 100% concordance with Cobas^® EGFR Mutation Test v2 and detection of all tissue confirmed mutations. In case of lower ccfDNA input, the risk of missing clinically relevant mutations should be considered. The use of a preanalytical ccfDNA quality control assay such as the Liquid IQ^® Panel is recommended to confidently interpret results, avoiding bias induced by non-specific genomic DNA and low input of specific tumoral ccfDNA fragments.

Abstract

Plasma-based tumor mutational profiling is arising as a reliable approach to detect primary and therapy-induced resistance mutations required for accurate treatment decision making. Here, we compared the FDA-approved Cobas^® EGFR Mutation Test v2 with the UltraSEEK™ Lung Panel on the MassARRAY^® System on detection of EGFR mutations, accompanied with preanalytical sample assessment using the novel Liquid IQ^® Panel. 137 cancer patient-derived cell-free plasma samples were analyzed with the Cobas^® and UltraSEEK™ tests. Liquid IQ^® analysis was initially validated (n = 84) and used to determine ccfDNA input for all samples. Subsequently, Liquid IQ^® results were applied to harmonize ccfDNA input for the Cobas^® and UltraSEEK™ tests for 63 NSCLC patients. The overall concordance between the Cobas^® and UltraSEEK™ tests was 86%. The Cobas^® test detected more EGFR exon19 deletions and L858R mutations, while the UltraSEEK™ test detected more T790M mutations. A 100% concordance in both the clinical (n = 137) and harmonized (n = 63) cohorts was observed when >10 ng of ccfDNA was used as determined by the Liquid IQ^® Panel. The Cobas^® and UltraSEEK™ tests showed similar sensitivity in EGFR mutation detection, particularly when ccfDNA input was sufficient. It is recommended to preanalytically determine the ccfDNA concentration accurately to ensure sufficient input for reliable interpretation and treatment decision making.

S6K1 blockade overcomes acquired resistance to EGFR-TKIs in non-small cell lung cancer

The development of resistance to EGFR Tyrosine kinase inhibitors (TKIs) in NSCLC with activating EGFR mutations is a critical limitation of this therapy. In addition to genetic alterations such as EGFR secondary mutation causing EGFR-TKI resistance, compensatory activation of signaling pathways without interruption of genome integrity remains to be defined. In this study, we identified S6K1/MDM2 signaling axis as a novel bypass mechanism for the development of EGFR-TKI resistance. The observation of S6K1 as a candidate mechanism for resistance to EGFR TKI therapy was investigated by interrogation of public databases and a clinical cohort to establish S6K1 expression as a prognostic/predictive biomarker. The role of S6K1 in TKI resistance was determined in in vitro gain-and-loss of function studies and confirmed in subcutaneous and orthotopic mouse lung cancer models. Blockade of S6K1 by a specific inhibitor PF-4708671 synergistically enhanced the efficacy of TKI without showing toxicity. The mechanistic study showed the inhibition of EGFR caused nuclear translocation of S6K1 for binding with MDM2 in resistant cells. MDM2 is a downstream effector of S6K1-mediated TKI resistance. Taken together, we present evidence for the reversal of resistance to EGFR TKI by the addition of small molecule S6K1/MDM2 antagonists that could have clinical benefit.

A Phase II Trial of Osimertinib as the First-Line Treatment of Non-Small Cell Lung Cancer Harboring Activating EGFR Mutations in Circulating Tumor DNA: LiquidLung-O-Cohort 1

Purpose

Osimertinib is a potent, irreversible third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor for both EGFR-activating and T790M resistant mutation. The treatment efficacy of osimertinib was assessed in previously untreated patients with metastatic non–small cell lung carcinoma (NSCLC) harboring activating EGFR mutations in circulating tumor DNA (ctDNA) as well as tumor DNA.

Materials and Methods

Patients with activating EGFR mutations in their tumor DNA underwent screening with ctDNA analysis using Mutyper and Cobas v2 assays. Enrolled subjects received osimertinib 80 mg, once daily. Primary endpoint was objective response rate (ORR) and secondary endpoints were ctDNA test sensitivity, progression-free survival (PFS), duration of response (DoR), and safety.

Results

Among 39 screened patients, 29 were ctDNA positive for activating EGFR mutations and 19 were enrolled (ex19del, n=11; L858R/L861Q, n=7; G719A, n=1). Median age was 70 and most patients had brain metastases (15/19, 79%). ctDNA test sensitivity for activating EGFR mutations was 74% using both methods and 62% (Mutyper) or 64% (Cobas v2) for individual methods. ORR was 68% (13/19), median PFS was 11.1 months (95% confidence interval [CI], 0.0 to 26.7), and median DoR was 17.6 months (95% CI, 3.5 to 31.7). ORR and median PFS were significantly superior with ex19del (91%; 21.9 months; 95% CI, 5.5 to 38.3) than with L858R/L861Q (43%; 5.1 months; 95% CI, 2.3 to 7.9). One patient discontinued the drug because of drug-related interstitial pneumonitis.

Conclusion

Osimertinib had favorable efficacy in the first-line treatment of metastatic NSCLC harboring activating EGFR mutations in ctDNA as well as tumor DNA.

Strategies for the successful implementation of plasma-based NSCLC genotyping in clinical practice

Upfront tumour genotyping is now considered an essential step in guiding treatment decision-making in the management of patients with advanced-stage non-small-cell lung cancer (NSCLC) in light of the ever-expanding toolbox of targeted therapies and immune-checkpoint inhibitors. However, genotyping of tumour biopsy samples is not feasible for all patients and, therefore, genomic analysis of circulating tumour DNA (ctDNA) has emerged as a compelling non-invasive option. Current guidelines universally recommend genotyping and support the use of ctDNA testing in certain settings, although they often omit the detail necessary for integrating these tests into clinical care on an individual basis. In this Perspective, we describe the rationale, promise and challenges associated with ctDNA-based NSCLC genotyping and suggest a framework for the implementation of these assays into routine clinical practice. We also offer considerations for the interpretation of ctDNA genotyping results, which, particularly when using next-generation sequencing panels, can be nuanced. Through the addition of this new approach to clinical practice, we propose that oncologists might finally be able to utilize effective genotyping in nearly all patients with advanced-stage NSCLC.

The efficacy and safety of osimertinib in treating nonsmall cell lung cancer: A PRISMA-compliant systematic review and meta-analysis

BACKGROUND

Epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) is the primary treatment in treating with EGFR mutant nonsmall cell lung cancer (NSCLC). This systematic review and meta-analysis aimed to evaluate the efficacy and safety of the third-generation EGFR-TKI, osimertinib, and summarize the risk factors associating with outcome after osimertinib treatment.

METHOD

The Ovid Medline, Embase, Cochrane Library, and Pubmed were systematically searched due to December 10, 2019. All the studies that mentioned the overall survival (OS), progression-free survival (PFS), treatment response, and adverse events (AEs) of osimertinib were involved in our study. Hazard ratio (HR) with 95% confidence intervals was used for comparing OS and PFS.

RESULT

A total of 47 studies were included in the systematic review, of which 14 studies were used to compare the efficacy between osimertinib and other EGFR-TKI or chemotherapy. Patients treating with osimertinib favors a higher OS and PFS in all the patients (HR = 0.56 and 0.38, P < .001, respectively), and in subgroup analysis, compared with other treatments. Median 55% T790 mutant NSCLC patients might experience partial response, and 25% of patients remained as stable disease. The incidence of severe AE ranged from 0% to 5%, and the most common severe AE was pneumonia (3%). Patients with the T858R mutation may have a better OS than Del 19 mutation (HR = 0.55, P = .037), while patients who have a smoking history may have a higher risk of progression than never-smoker patients (HR = 1.47, P = .028).

CONCLUSION

Osimertinib has an impressive antitumor activity compared with prior EGFR-TKI and chemotherapy with an acceptable response and tolerable AEs. EGFR mutation type and smoking status were the risk factors for mortality and progression in NSCLC patients.

Real-world osimertinib for EGFR mutation-positive non-small-cell lung cancer with acquired T790M mutation

Aim: Osimertinib is a key drug for EGFR mutation-positive non-small-cell lung cancer (NSCLC). As the hazards ratio of overall survival in comparison with first-generation EGFR-tyrosine kinase inhibitors was almost similar between FLAURA and ARCHER 1050, salvage use of osimertinib is still a treatment option. Patients & methods: We retrospectively analyzed the clinical courses of EGFR mutation-positive NSCLC patients who were potential candidates for salvage osimertinib. Results: Among 524 patients enrolled from five hospitals, 302 patients underwent biopsy, with 52.6% detection rate of T790M. Osimertinib was administered in 93.6% of the T790M-positive patients. The overall response rate and median progression-free survival time of osimertinib were calculated with 147 patients, to be 55.6% and 17.2 months, respectively. Conclusion: Osimertinib is active for T790M-driven acquired resistance in EGFR-mutant NSCLC, but the detection of T790M was unsatisfactory. Clinical Trial Registration: UMIN000028989 (UMIN Clinical Trials Registry).

Molecular therapeutic targets in non-small cell lung cancer

INTRODUCTION

Several targetable genetic alterations have been identified in non-small cell lung cancers (NSCLC) and drugs targeting these alterations have been approved for the management of advanced NSCLC patients. Driver mutations with emerging clinical trial data include EGFR exon 20 insertion mutations, MET amplification, KRAS G12 C point mutations, RET rearrangements, HER2 amplification and mutations, and FGFR amplification and translocations.

AREAS COVERED

We reviewed English-language articles indexed in Medline and PubMed up to the 1^st of June 2020. In addition, the proceedings of major conferences were reviewed for relevant abstracts. We report data published regarding targeted therapies which are currently approved and for those which are emerging in advanced or metastatic NSCLC.

EXPERT REVIEW

While these drugs have been shown to be efficacious and tolerable, resistance almost always develops. Though next-generation tyrosine kinase inhibitors (TKIs) have been developed, the appropriate sequencing of these drugs is not clear. Evaluating combination therapies to prevent or delay the onset of resistance and understanding mechanisms of resistance are critical areas of emerging research.

Evaluation of plasma EGFR mutation as an early predictor of response of erlotinib plus bevacizumab treatment in the NEJ026 study

Background

The NEJ026 Phase 3 study demonstrated that erlotinib and bevacizumab (BE)-treated NSCLC patients with EGFR mutations had significantly better progression-free survival (PFS) than those treated with erlotinib alone (E). This study included a prospective analysis of the relationship between the mutational status of EGFR in plasma circulating tumor DNA (ctDNA) and the efficacy of TKI monotherapy or combination therapy. We describe these results herein.

Methods

Plasma samples were collected from patients enrolled in NEJ026 at the start of treatment (P0), 6 weeks after the start of treatment (P1), and upon confirmation of progressive disease (P2). Plasma ctDNA was analyzed using a modified PNA-LNA PCR clamp method. PFS and OS according to EGFR status at the time of plasma collection were evaluated.

Findings

Plasma activating EGFR mutation (aEGFR) at P0 was detected in 68% of cases; patients without plasma aEGFR had longer PFS. The frequency of T790M mutation at P2 was similar in both arms: 8 (19.0%) in BE and 11 (20.8%) in E. Based on the aEGFR profiles, PFS was evaluated among three groups: type A [P0(-), P1(-)], type B [P0(+), P1(-)], and type C [P0(+), P1(+)]. This revealed that BE was more efficacious than E, and that BE was associated with improved PFS in all types.

Interpretation

Pre-treatment plasma aEGFR status have a potential of early predictor of response of TKI efficacy. Monitoring plasma aEGFR mutation will contribute to selection and continuation of treatment with BE or E.

Funding

Chugai Pharmaceutical.

Early prediction of resistance to tyrosine kinase inhibitors by plasma monitoring of EGFR mutations in NSCLC: a new algorithm for patient selection and personalized treatment

In Non-Small-Cell Lung Cancer (NSCLC) patients treated with Tyrosine Kinase-Inhibitors (TKIs) therapy, the emergence of acquired resistance can be investigated by plasma monitoring of circulating tumor DNA (ctDNA). A series of 116 patients with EGFR-positive lung adenocarcinomas were treated with first/second generation EGFR TKIs. At clinical progression, 64 (55%) EGFR T790M plasma positive patients were subjected to second line-treatment with osimertinib and strictly monitored during the first month of therapy. Plasma analysis by the EGFR Cobas test showed in 57 (89%) cases a substantial decrease in the levels of the sensitizing EGFR mutant allele (sEGFRma), down to a not detectable value. These patients were defined as plasmatic good responders (PGR). In 7 (11%) patients, the sEGFRma did not drop to zero (plasmatic poor responders, PPR). In these latter cases, Massive Parallel Sequencing (MPS) analysis at the end of the first month and at clinical progression showed the presence of resistant-inducing mutations, including MET and HER2 gene amplification, KRAS and PIK3CA gene mutations. PPR showed disease progression in 5 (71%) cases, stable disease in 2 (29%) cases, and a shorter median Progression-free survival (PFS) (4.3 ± 1.1 months) than that observed in PGR (13.3 ± 1.2 months) (P < 0.0001). Our data indicate that plasma monitoring by a simple RT-PCR-based EGFR mutation test in the first month of treatment may be useful for a rapid identification of patients to be subjected to further characterization by MPS. A diagnostic algorithm for an early detection of resistance-inducing mutations and patient management is reported.