Receptor tyrosine kinase gene expression profiling of orbital rhabdomyosarcoma unveils MET as a potential biomarker and therapeutic target

Receptor tyrosine kinases (RTKs) serve as molecular targets for the development of novel personalized therapies in many malignancies. In the present study, expression pattern of receptor tyrosine kinases and its clinical significance in orbital RMS has been explored. Eighteen patients with histopathologically confirmed orbital RMS formed part of this study. Comprehensive q-PCR gene expression profiles of 19 RTKs were generated in the cases and controls. The patients were followed up for 59.53 ± 20.93 years. Clustering and statistical analysis tools were applied to identify the significant combination of RTKs associated with orbital rhabdomyosarcoma patients. mRNA overexpression of RTKs which included MET, AXL, EGFR was seen in 60-80% of cases; EGFR3, IGFR2, FGFR1, RET, PDGFR1, VEGFR2, PDGFR2 in 30-60% of cases; and EGFR4, FGFR3,VEGFR3 and ROS,IGFR1, EGFR1, FGFR2, VEGFR1 in 10-30% of cases. Immunoexpression of MET was seen in 89% of cases. A significant association was seen between MET mRNA and its protein expression. In all the cases MET gene expression was associated with worst overall survival (P = 0.03).There was a significant correlation of MET mRNA expression with RET, ROS, AXL, FGFR1, FGFR3, PDGFR1, IGFR1, VEGFR2, and EGFR3 genes. Association between MET gene and collective expression of RTKs was further evaluated by semi-supervised gene cluster analysis and Principal component analysis, which showed well-separated tumor clusters. MET gene overexpression could be a useful biomarker for identifying high risk orbital rhabdomyosarcoma patients. Well-separated tumor clusters confirmed the association between MET gene and collective expression of RTK genes. Therefore, the therapeutic potential of multi-kinase inhibitors targeting MET and the 9 other significant RTKs needs to be explored.

Liquid Biopsy in NSCLC: An Investigation with Multiple Clinical Implications

Tissue biopsy is essential for NSCLC diagnosis and treatment management. Over the past decades, liquid biopsy has proven to be a powerful tool in clinical oncology, isolating tumor-derived entities from the blood. Liquid biopsy permits several advantages over tissue biopsy: it is non-invasive, and it should provide a better view of tumor heterogeneity, gene alterations, and clonal evolution. Consequentially, liquid biopsy has gained attention as a cancer biomarker tool, with growing clinical applications in NSCLC. In the era of precision medicine based on molecular typing, non-invasive genotyping methods became increasingly important due to the great number of oncogene drivers and the small tissue specimen often available. In our work, we comprehensively reviewed established and emerging applications of liquid biopsy in NSCLC. We made an excursus on laboratory analysis methods and the applications of liquid biopsy either in early or metastatic NSCLC disease settings. We deeply reviewed current data and future perspectives regarding screening, minimal residual disease, micrometastasis detection, and their implication in adjuvant and neoadjuvant therapy management. Moreover, we reviewed liquid biopsy diagnostic utility in the absence of tissue biopsy and its role in monitoring treatment response and emerging resistance in metastatic NSCLC treated with target therapy and immuno-therapy.

Targeted Therapy for Non–Small Cell Lung Cancer

This article provides an updated review of the management of oncogene-driven non-small cell lung cancer. The use of targeted therapies for lung cancer driven by EGFR, ALK, ROS1, RET, NTRK, HER2, BRAF, MET, and KRAS are discussed, both in the first-line setting and in the setting of acquired resistance.

Liquid biopsy and non-small cell lung cancer: are we looking at the tip of the iceberg?

The possibility to analyse the tumour genetic material shed in the blood is undoubtedly one of the main achievements of translational research in the latest years. In the modern clinical management of advanced non-small cell lung cancer, molecular characterisation plays an essential role. In parallel, immunotherapy is widely employed, but reliable predictive markers are not available yet. Liquid biopsy has the potential to face the two issues and to increase its role in advanced NSCLC in the next future. The aim of this review is to summarise the main clinical applications of liquid biopsy in advanced non-small cell lung cancer, underlining both its potential and limitations from a clinically driven perspective.

Recent advances in lung cancer genomics: Application in targeted therapy

Genomic characterization of lung cancer has not only improved our understanding of disease biology and carcinogenesis but also revealed several therapeutic opportunities. Targeting tumor dependencies on specific genomic alterations (oncogene addiction) has accelerated the therapeutic developments and significantly improved the outcomes even in advanced stage of disease. Identification of genomic alterations predicting response to specific targeted treatment is the key to success for this "personalized treatment" approach. Availability of multiple choices of therapeutic options for specific genomic alterations highlight the importance of optimum sequencing of drugs. Multiplex gene testing has become mandatory in view of constantly increasing number of therapeutic targets and effective treatment options. Influence of genomic characteristics on response to immunotherapy further makes comprehensive genomic profiling necessary before therapeutic decision making. A comprehensive elucidation of resistance mechanisms and directed treatments have made the continuum of care possible and transformed this deadly disease into a chronic condition. Liquid biopsy-based approach has made the dynamic monitoring of disease possible and enabled treatment optimizations accordingly. Current lung cancer management is the perfect example of "precision-medicine" in clinical oncology.

MET alterations and their impact on the future of non-small cell lung cancer (NSCLC) targeted therapies

Introduction: The MET gene and its pathway normally plays a crucial role in cell homeostasis, motility, and apoptosis. However, when the MET gene is altered, there is an imbalance toward cell proliferation and invasion commonly seen in numerous different types of cancers. The heterogeneous group of MET alterations that includes MET amplification, MET exon 14 skipping mutation, and MET fusions has been difficult to diagnose and treat. Currently, treatments are focused on tyrosine kinase inhibitors but now there is emerging data on novel MET-targeted therapies including monoclonal antibodies and antibody-drug conjugates that have emerged.Areas covered: We introduce new emerging data on MET alterations in non-small cell lung cancer (NSCLC) that has contributed to advances in MET targeted therapeutics. We offer our perspective and examine new information on the mechanisms of the MET alterations in this review.Expert opinion: Given the trends currently involving the targeting of MET altered malignancies, there will most likely be a continued rapid expansion of testing, novel tyrosine kinase inhibitors and potent antibody approaches. Combination treatments will be necessary to optimize management of advanced and early disease.

Detection of MET exon 14 skipping mutations in non-small cell lung cancer: overview and community perspective

Introduction: Non-small cell lung cancer (NSCLC), which accounts for the majority of lung cancer diagnoses in the United States, has many known driver mutations, including MET exon 14 skipping mutation (METex14). The detection of oncogenic driver mutations in NSCLC and the development of drugs to target these alterations, including METex14, has created the need for accurate and reliable testing, of which next-generation sequencing (NGS) is the gold standard. However, detection of METex14 in patients with NSCLC can be challenging due to the complex biology of METex14 and the abilities of different NGS platforms to detect METex14.Areas covered: This review provides an overview of METex14 biology, discusses the optimal platforms for the detection of METex14 in NSCLC, and provides an overview of the use of NGS in the community setting.Expert opinion: Broad molecular testing is crucial for identifying actionable oncogenic drivers in NSCLC. METex14 is a complex oncogenic driver mutation requiring carefully optimized platforms for proper detection. To identify patients eligible for targeted therapies - including therapies targeting novel oncogenic drivers, such as MET inhibitors - community oncologists need to be aware of both the use of NGS platforms and the differences in their capabilities to detect certain oncogenic drivers.

Translational pharmacokinetic-pharmacodynamic modeling of preclinical and clinical data of the oral MET inhibitor tepotinib to determine the recommended phase II dose

Tepotinib is a highly selective and potent MET inhibitor in development for the treatment of patients with solid tumors. Given the favorable tolerability and safety profiles up to the maximum tested dose in the first‐in‐human (FIH) trial, an efficacy‐driven translational modeling approach was proposed to establish the recommended phase II dose (RP2D). To study the in vivo pharmacokinetics (PKs)/target inhibition/tumor growth inhibition relationship, a subcutaneous KP‐4 pancreatic cell‐line xenograft model in mice with sensitivity to MET pathway inhibition was selected as a surrogate tumor model. Further clinical PK and target inhibition data (derived from predose and postdose paired tumor biopsies) from a FIH study were integrated with the longitudinal PKs and target inhibition profiles from the mouse xenograft study to establish a translational PK/pharmacodynamic (PD) model. Preclinical data showed that tumor regression with tepotinib treatment in KP‐4 xenograft tumors corresponded to 95% target inhibition. We therefore concluded that a PD criterion of sustained, near‐to‐complete (>95%) phospho‐MET inhibition in tumors should be targeted for tepotinib to be effective. Simulations of dose‐dependent target inhibition profiles in human tumors that exceeded the PD threshold in more than 90% of patients established an RP2D of tepotinib 500 mg once daily. This translational mathematical modeling approach supports an efficacy‐driven rationale for tepotinib phase II dose selection of 500 mg once daily. Tepotinib at this dose has obtained regulatory approval for the treatment of patients with non‐small cell lung cancer harboring MET exon 14 skipping.

Uncommon targets in non-small cell lung cancer: Everyone wants a slice of cake

Target therapies completely changed the clinical approach in EGFR mutated and ALK rearranged non-small cell lung cancer, ensuring these patients exceptional outcomes with a better toxicity profile compared to conventional chemotherapy. In recent years, beyond EGFR and ALK alterations, new data are emerging about less common alterations, new drugs have been already approved and others agents have been recently investigated or are currently under investigation. In this review we will discuss some uncommon alterations in non-small cell lung cancer such as ROS1, BRAF, RET, HER2, NTRK, MET and other targets that are in an early evaluation phase. We will summarize the characteristics of patients harboring these alterations, the already approved or under investigation therapies and the related resistance mechanisms.

Novel Emerging Molecular Targets in Non-Small Cell Lung Cancer

In the scenario of systemic treatment for advanced non-small cell lung cancer (NSCLC) patients, one of the most relevant breakthroughs is represented by targeted therapies. Throughout the last years, inhibitors of the epidermal growth factor receptor (EGFR), anaplastic lymphoma kinase (ALK), c-Ros oncogene 1 (ROS1), and V-raf murine sarcoma viral oncogene homolog B (BRAF) have been approved and are currently used in clinical practice. However, other promising molecular drivers are rapidly emerging as therapeutic targets. This review aims to cover the molecular alterations with a potential clinical impact in NSCLC, including amplifications or mutations of the mesenchymal–epithelial transition factor (MET), fusions of rearranged during transfection (RET), rearrangements of the neurotrophic tyrosine kinase (NTRK) genes, mutations of the Kirsten rat sarcoma viral oncogene (KRAS) and phosphatidylinositol-4,5-bisphosphate 3-kinase, catalytic subunit alpha (PIK3CA), as well as amplifications or mutations of human epidermal growth factor receptor 2 (HER2). Additionally, we summarized the current status of targeted agents under investigation for such alterations. This revision of the current literature on emerging molecular targets is needed as the evolving knowledge on novel actionable oncogenic drivers and targeted agents is expected to increase the proportion of patients who will benefit from tailored therapeutic approaches.

Responses to crizotinib and cabozantinib in patient with lung adenocarcinoma harboring mesenchymal-epithelial transition factor exon 14 skipping mutation: A case report

RATIONALE

Lung cancer is a leading cause of cancer-related mortality worldwide. Currently, targeted therapy has proved highly efficient in the treatment of advanced non-small cell lung cancer (NSCLC). Mesenchymal-epithelial transition factor (MET) is considered a validated molecular target in NSCLC. Given the low incidence of MET exon 14 skipping mutation, the planning of precision treatment for patients is a clinical problem that needs to be solved. In this report, we present a MET-positive case that benefited from crizotinib and cabozantinib treatment.

PATIENT CONCERNS

A 77-year-old patient was diagnosed with lung adenocarcinoma in our hospital. Positron emission tomography-computed tomography (PET-CT) showed a right upper lobe mass (58 × 56 mm, SUVmax 15.6), right hilar enlarged lymph nodes, and multiple bone and left adrenal metastases (c-T3N1M1c).

DIAGNOSES

MET exon 14 mutation (exon14, c.2888-1G>C) was examined using the lung puncture sample by next generation sequencing. Therefore, the patient was diagnosed with late-stage lung adenocarcinoma with MET exon14 skipping gene mutation.

INTERVENTIONS

Crizotinib was given as the first-line treatment from August 2019. Considering the resistance of crizotinib, cabozantinib was given for second-line treatment.

OUTCOMES

Crizotinib was administered (250 mg bid) for 8 months, and her disease achieved partial regression (PR) and progression-free survival (PFS), which lasted for 8 months. The patient also reached PR after the second-line treatment with cabozantinib, and is currently under follow-up, with an overall survival (OS) of >12 months.

LESSONS

As MET exon 14 skipping mutation is rare in clinical practices, MET-TKIs (tyrosine kinase inhibitors) treatment can boost curative effects and improve prognosis of patients with advanced lung adenocarcinoma. This case report supports a rationale for the treatment of lung adenocarcinoma patients with a MET exon 14 skipping mutation and provides alternative treatment options for these types of NSCLC patients.

Treatment of Non-Small-Cell Lung Cancer Based on Circulating Cell-Free DNA and Impact of Variation Allele Frequency

BACKGROUND

Next-generation sequencing of circulating cell-free DNA (cfDNA) can identify sensitizing and resistance mutations in non-small-cell lung cancer (NSCLC). cfDNA is helpful when tissue is insufficient for genomic testing or repeat biopsy is not feasible or poses unacceptable risk. Here we report the experience of cfDNA testing at the time of diagnosis and how this intervention can help avoid further invasive interventions, how it can be used to determine initiation of therapy, and how variation allele frequency of the somatic alteration affects response to subsequent treatment.

PATIENTS AND METHODS

This is a single-institution retrospective study of patients with advanced NSCLC who had cfDNA from plasma tested using the Guardant360 panel, which identifies somatic genomic alterations by massive parallel sequencing of target genes. An institutional Clinical Laboratory Improvement Amendments tissue panel using fluorescence in situ hybridization (for MET, RET, ROS1, and ALK) and next-generation sequencing for selected genes was used for tissue analysis. Actionable mutations are those with US Food and Drug Administration-approved targeted therapies (EGFR, ALK, ROS, BRAF, NTRK fusions) or therapies soon to be approved (RET fusions and MET amplifications, or MET exon 14 skipping mutation).

RESULTS

A total of 163 blood samples from 143 patients were evaluated, 82 at diagnosis and 81 at disease progression. A total of 94 cases had tissue and cfDNA testing performed within 12 weeks of each other. Seventy-six (81%) of 94 cases were concordant, of which 22 cases were concordantly positive and 54 concordantly negative. Eighteen (19%) of 94 cases were discordant, of which 11 had negative blood and positive tissue results, and 7 had positive blood and negative tissue results. cfDNA testing had a sensitivity of 67% (95% confidence interval [CI], 51%, 83%), specificity of 89% (95% CI, 81%, 97%), negative predictive value of 83% (95% CI, 74%, 92%), and positive predictive value of 76% (95% CI, 60%, 91%). Nineteen (21%) of 82 cfDNA samples analyzed at diagnosis had actionable mutations identified (4 EGFR exon 19 deletion, 2 EGFR exon 21 L858R, 2 EGFR L861Q, 1 L861R, 4 EML4-ALK fusion, 2 CD74-ROS1 fusion, 2 MET exon 14 skipping mutation, 2 KIF5B-RET fusion). Of the 82 patients with cfDNA testing performed at the time of diagnosis, 8 patients (10%) initiated targeted therapy on the basis of cfDNA results only, with 6 patients experiencing partial response, 1 patient complete response, and 1 patient stable disease. The response rate for patients who initiated targeted therapies on the basis of cfDNA only at diagnosis was 88%. Variant allele frequency had no impact on response.

CONCLUSIONS

Initiation of targeted therapy for advanced NSCLC was feasible based only on identification of actionable mutations by cfDNA testing in 9% of the cases for which tissue diagnosis could not be obtained. Actionable targets were identified by cfDNA in 20% of the samples sent at diagnosis. A substantial number of patients benefited from cfDNA testing at initial diagnosis because it identified actionable mutations that led to appropriate targeted treatments.

Prolonged survival and response to tepotinib in a non-small-cell lung cancer patient with brain metastases harboring MET exon 14 mutation: a research report

Tyrosine kinase inhibitors (TKIs) have transformed the standard of care in lung cancer. A number of TKIs have been discovered that specifically target oncogenes, including MET receptor tyrosine kinase. Second-generation MET TKIs are showing improved efficacy over first-generation TKIs. Herein, we report a case of a patient with metastatic lung adenocarcinoma harboring a MET exon 14 splice site mutation who has had prolonged disease control by a second-generation MET-TKI tepotinib. A 66-yr-old man was diagnosed with stage IV lung adenocarcinoma. He was started on carboplatin, paclitaxel, and bevacizumab, but had severe toxicity. He was switched to pembrolizumab as his tumor was PD-L1 70%, and molecular testing was not yet performed because of insufficient tissue. A bronchoscopy with endobronchial ultrasound was performed and a MET exon 14 splice site mutation was detected by next-generation sequencing. Upon progression, he was then enrolled in a clinical trial of tepotinib and continues with stable disease for more than 45 cycles and 31 mo. The MET receptor tyrosine kinase and the ligand hepatocyte growth factor (HGF) have been implicated as oncogenes and drivers of non-small-cell lung cancer (NSCLC). Newer MET TKIs including capmatinib and tepotinib more recently showed not only improved localized control and response, but early data suggests intracranial activity as compared to first-generation MET TKIs, both in the front-line and the refractory setting. This is a case report demonstrating an effective duration of response in a patient with widely metastatic lung adenocarcinoma harboring a MET exon 14 mutation.

Identification of Iminium Intermediates Generation in the Metabolism of Tepotinib Using LC-MS/MS: In Silico and Practical Approaches to Bioactivation Pathway Elucidation

Tepotinib (Tepmetko™, Merck) is a potent inhibitor of c-Met (mesenchymal-epithelial transition factor). In March 2020, tepotinib (TEP) was approved for use in Japan for the treatment of patients who suffered from non-small cell lung cancers (NSCLC) harboring an MET exon 14 skipping alteration and have progressed after platinum-based therapy. Practical and in silico experiments were used to screen for the metabolic profile and reactive intermediates of TEP. Knowing the bioactive center and structural alerts in the TEP structure helped in making targeted modifications to improve its safety. First, the prediction of metabolism vulnerable sites and reactivity metabolic pathways was performed using the StarDrop WhichP450™ module and the online Xenosite reactivity predictor tool, respectively. Subsequently, in silico data were used as a guide for the in vitro practical work. Second, in vitro phase I metabolites of TEP were generated from human liver microsome (HLM) incubations. Testing for the generation of unstable reactive intermediates was performed using potassium cyanide as a capturing agent forming stable cyano adduct that can be characterized and identified using liquid chromatography tandem mass spectrometry (LC-MS/MS). Third, in silico toxicity assessment of TEP metabolites was performed, and structural modification was proposed to decrease their side effects and to validate the proposed bioactivation pathway using the DEREK software. Four TEP phase I metabolites and four cyano adducts were characterized. The reactive intermediate generation mechanism of TEP may provide an explanation of its adverse reactions. The piperidine ring is considered a structural alert for toxicity as proposed by the DEREK software and a Xenosite reactivity model, which was confirmed by practical experiments. Steric hindrance or isosteric replacement at α-carbon of the piperidine ring stop the bioactivation sequence that was confirmed using the DEREK software. More drug discovery studies can be performed using this perception permitting the design of new drugs with an increased safety profile. To our knowledge, this is the first study for the identification of in vitro phase I metabolites and reactive intermediates in addition to toxicological properties of the metabolites for TEP that will be helpful for the evaluation of TEP side effects and drug-drug interactions in TEP-treated patients.

Tyrosine kinase inhibitors for solid tumors in the past 20 years (2001-2020)

Tyrosine kinases are implicated in tumorigenesis and progression, and have emerged as major targets for drug discovery. Tyrosine kinase inhibitors (TKIs) inhibit corresponding kinases from phosphorylating tyrosine residues of their substrates and then block the activation of downstream signaling pathways. Over the past 20 years, multiple robust and well-tolerated TKIs with single or multiple targets including EGFR, ALK, ROS1, HER2, NTRK, VEGFR, RET, MET, MEK, FGFR, PDGFR, and KIT have been developed, contributing to the realization of precision cancer medicine based on individual patient's genetic alteration features. TKIs have dramatically improved patients' survival and quality of life, and shifted treatment paradigm of various solid tumors. In this article, we summarized the developing history of TKIs for treatment of solid tumors, aiming to provide up-to-date evidence for clinical decision-making and insight for future studies.

Optimizing therapy sequence to prevent patient attrition in EGFR mutation-positive advanced or metastatic NSCLC

Clinical trial and real-world data in non-small-cell lung cancer indicate that 10-60% of patients that progressed on first- or second-generation EGFR-targeting tyrosine kinase inhibitors (TKI) do not receive systemic second-line therapy. In our article, we discuss efficacy, safety and treatment duration with different EGFR-TKIs and stress the need for delivery of the most efficacious therapy in the first-line. We also provide our perspective on analysis of circulating tumor DNA and the role of EGFR-TKI in combined therapies. Finally, we review new therapeutic options to overcome resistance to EGFR-TKI. We believe that overall treatment duration and access to different medications in subsequent lines of therapy should be considered when planning the optimal treatment strategy.

Tepotinib Efficacy in a Patient with Non-Small Cell Lung Cancer with Brain Metastasis Harboring an HLA-DRB1-MET Gene Fusion

Alterations in c-MET, a tyrosine kinase receptor encoded by the MET gene, have been reported in approximately 3% of non-small cell lung cancer (NSCLC) cases and carry important treatment implications. The best studied genetic alterations are exon 14 skipping and gene amplification; however, gene rearrangement has also been described, and multiple fusion partners have been reported. Recently, in METex14-mutated NSCLC, multitarget tyrosine kinase inhibitors (TKIs), such as crizotinib and cabozantinib, as well as MET-selective TKIs, such as tepotinib and capmatinib, have demonstrated durable responses. In this study, we present the case of a 41-year-old woman with advanced NSCLC harboring an HLA-DRB1-MET gene fusion. The patient was offered successively two different MET multikinase inhibitors, crizotinib and cabozantinib, and the selective inhibitor tepotinib. Each time, including under tepotinib, the patient experienced rapid and complete responses associated with a tremendous improvement in her physical function. KEY POINTS: To our knowledge, this is the first report of a patient with non-small cell lung cancer harboring an HLA-DRB1-MET gene fusion demonstrating a clinical response to multiple MET inhibitors, including tepotinib. This finding illustrates the efficacy and rationale to targeting MET regardless of fusion partner and gives insight to pooling of patients with different MET fusion products in trials assessing safety and efficacy of novel molecules.

The METeoric rise of MET in lung cancer

Over the years, there has been a continuous increase in clinically relevant driver mutations in patients with non-small cell lung cancer (NSCLC). Among these, dysregulated activation of the MET tyrosine kinase receptor has gained importance due to the recent development of quite effective treatments. MET dysregulation encompasses a heterogeneous array of alterations leading to the prolonged activation of the cellular MET (c-MET or MET) receptor and downstream proliferation pathways. It can arise through several mechanisms, including gene amplification, overexpression of the receptor and/or its ligand hepatocyte growth factor, and the acquisition of activating mutations. MET mutations are found in approximately 3% to 5% of patients with NSCLC, mainly adenocarcinoma, and are overrepresented in the sarcomatoid subtype. De novo MET amplifications are found in 1% to 5% of NSCLC cases, also predominantly in adenocarcinoma. In the current review, the authors discussed the biology of MET, how to diagnose clinically relevant alterations, and the rising clinical importance of these alterations in light of the emergence of multiple targeted therapies, both within the context of MET as a driver of resistance and in its own right.

Retrospective analysis of real-world data to determine clinical outcomes of patients with advanced non-small cell lung cancer following cell-free circulating tumor DNA genomic profiling

OBJECTIVES

Liquid biopsy and comprehensive genomic profiling (CGP) of circulating tumor DNA (ctDNA) are increasingly used for detection of targetable genomic alterations (GA) in non-small cell lung cancer (NSCLC). To examine the clinical outcomes for patients following CGP using liquid biopsy versus tissue biopsy, receipt of matched targeted therapy post-CGP and associated outcomes were evaluated in the real-world setting.

METHODS

6491 patients with NSCLC and liquid biopsy (N = 937 tests) and/or tissue (N = 5582 tests) CGP were included in a de-identified commercial clinico-genomic database. Targetable GAs included National Comprehensive Cancer Network NSCLC guideline biomarkers. Clinical characteristics, real-world progression, and real-world response (rwR) were obtained via technology-enabled abstraction of clinician notes and radiology/pathology reports.

RESULTS

At the time of liquid biopsy CGP, 53% (496/937) of patients were documented to have received ≥1 line of prior therapy (tissue CGP: 13%, 735/5582). 90% (832/928) of liquid biopsy cases had evidence of ctDNA. A targetable GA was detected in 20% (188/937) of liquid biopsy and 22% (1215/5582) of tissue CGP cases. Use of matched targeted therapy overall was similar post-liquid biopsy or post-tissue CGP but varied considerably across emerging (25%, 79/317) versus standard of care (SOC) (74%, 475/640) GA. Real-world-progression free survival for patients receiving SOC first line matched targeted therapy administered following liquid biopsy (n = 33) and tissue (n = 229) CGP were similar (13.8 vs 10.6 months; aHR = 0.68 [0.36-1.26]). Among patients evaluated for rwR, overall response rate (partial/complete response) to matched targeted therapy post-liquid biopsy CGP was 75% (39/52) versus 66% post-tissue CGP (254/385, P = 0.51).

CONCLUSION

Retrospective analysis of real-world clinico-genomic data demonstrated that clinical outcomes on matched targeted therapy were similar following liquid biopsy and tissue CGP in NSCLC, which suggests routine clinical use of liquid biopsy CGP can reliably guide therapy selection.

Leptomeningeal Metastases in Non-small Cell Lung Cancer: Optimal Systemic Management in NSCLC With and Without Driver Mutations

OPINION STATEMENT

As a devastating complication of non-small cell lung cancer (NSCLC), the incidence of leptomeningeal metastasis (LM) is rising, largely due to overall longer survival of NSCLC, especially in patients with targetable molecular driver mutations. There is no clear consensus on the optimal management of LM. This review will cover recent advances in diagnosis, monitoring, and treatment of LM in NSCLC. In LM without oncogene drivers, systemic chemotherapy, intrathecal therapy, and radiation have modestly improved the clinical outcomes. Emerging data have also suggested encouraging activity of immunotherapy. At the same time, in LM with sensitizing EGFR mutations, osimertinib should be considered regardless of T790M status. Pulse erlotinib, afatinib, and newer agents with improved CNS penetration have also shown benefits. Moreover, accumulating evidences support potential benefits of molecularly targeted therapy in ALK-rearranged and other oncogene-driven NSCLC with LM. Future studies are warranted to better define the underlying mechanism, to optimize the clinical management, and to improve patient outcomes.

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.

Targeting MET Dysregulation in Cancer

Aberrant MET signaling can drive tumorigenesis in several cancer types through a variety of molecular mechanisms including MET gene amplification, mutation, rearrangement, and overexpression. Improvements in biomarker discovery and testing have more recently enabled the selection of patients with MET-dependent cancers for treatment with potent, specific, and novel MET-targeting therapies. We review the known oncologic processes that activate MET, discuss therapeutic strategies for MET-dependent malignancies, and highlight emerging challenges in acquired drug resistance in these cancers. SIGNIFICANCE: Increasing evidence supports the use of MET-targeting therapies in biomarker-selected cancers that harbor molecular alterations in MET. Diverse mechanisms of resistance to MET inhibitors will require the development of novel strategies to delay and overcome drug resistance.

Optimal Management of Patients with Advanced NSCLC Harboring High PD-L1 Expression and Driver Mutations

OPINION STATEMENT

Patients with stage IV or recurrent/metastatic non-small cell lung cancer (NSCLC) whose tumors harbor high PD-L1 expression and driver mutations with approved targeted treatments (EGFR, ALK, BRAF^V600E, ROS1) should receive initial therapy with targeted therapy based on impressive clinical activity. PD-(L)1 inhibitors have demonstrated minimal activity in many driver mutation subsets including EGFR and ALK and appears to have more benefit in smoking-associated oncogenic drivers (KRAS, BRAF). For KRAS-driven tumors, co-mutations such as STK11/LKB1 are negative predictive markers of immunotherapy with or without chemotherapy. Therefore, driver mutations need to be evaluated before pursuing immunotherapy independent of PD-L1 expression level. Caution should be used with TKIs following or concurrent with immunotherapy owing to potentially increased toxicity. New immunotherapy combinations are needed especially for oncogene-driven tumors associated with never or light smoking history.

Targeting the MET-Signaling Pathway in Non-Small-Cell Lung Cancer: Evidence to Date

The c-MET proto-oncogene (MET) plays an important role in lung oncogenesis, affecting cancer-cell survival, growth and invasiveness. The MET receptor in non-small-cell lung cancer (NSCLC) is a potential therapeutic target. The development of high-output next-generation sequencing techniques has enabled better identification of anomalies in the MET pathway, like the MET exon-14 (METex14) mutation. Moreover, analyses of epidermal growth factor-receptor (EGFR) and mechanisms of resistance to tyrosine-kinase inhibitors (TKIs) demonstrated the importance of MET amplification as an escape mechanism in patients with TKI-treated EGFR-mutated NSCLCs. This review summarizes the laboratory findings on MET and its anomalies, trial results on METex14 alterations and MET amplification in non-EGFR mutated NSCLCs, and acquired resistance to TKI in EGFR-mutated NSCLCs. The outcomes of the first trials with anti-MET agents on non-selected NSCLC patients or those selected for MET overexpression were disappointing. Two situations seem the most promising today for the use of anti-MET agents to treat these patients: tumors harboring METex14 and those EGFR-sensitive mutation mutated under TKI-EGFR with a MET-amplification mechanism of resistance or EGFR-resistance mutation.

MET receptor in oncology: From biomarker to therapeutic target

First discovered in the 1984, the MET receptor tyrosine kinase (RTK) and its ligand hepatocyte growth factor or HGF (also known as scatter factor or SF) are implicated as key players in tumor cell migration, proliferation, and invasion in a variety of cancers. This pathway also plays a key role during embryogenesis in the development of muscular and nervous structures. High expression of the MET receptor has been shown to correlate with poor prognosis and resistance to therapy. MET exon 14 splicing variants, initially identified by us in lung cancer, is actionable through various tyrosine kinase inhibitors (TKIs). For this reason, this pathway is of interest as a therapeutic target. In this chapter we will be discussing the history of MET, the genetics of this RTK, and give some background on the receptor biology. Furthermore, we will discuss directed therapeutics, mechanisms of resistance, and the future of MET as a therapeutic target.

Complex Oncological Decision-Making Utilizing Fast-and-Frugal Trees in a Community Setting-Role of Academic and Hybrid Modeling

Non-small cell lung cancer is a devastating disease and with the advent of targeted therapies and molecular testing, the decision-making process has become complex. While established guidelines and pathways offer some guidance, they are difficult to utilize in a busy community practice and are not always implemented in the community. The rationale of the study was to identify a cohort of patients with lung adenocarcinoma at a City of Hope community site (n = 11) and utilize their case studies to develop a decision-making framework utilizing fast-and-frugal tree (FFT) heuristics. Most patients had stage IV (N = 9, 81.8%) disease at the time of the first consultation. The most common symptoms at initial presentation were cough (N = 5, 45.5%), shortness of breath (N = 3, 27.2%), and weight loss (N = 3, 27.2%). The Eastern Cooperative Oncology Group (ECOG) performance status ranged from 0-1 in all patients in this study. Distribution of molecular drivers among the patients were as follows: EGFR (N = 5, 45.5%), KRAS (N = 2, 18.2%), ALK (N = 2, 18.2%), MET (N = 2, 18.2%), and RET (N = 1, 9.1%). Seven initial FFTs were developed for the various case scenarios, but ultimately the decisions were condensed into one FFT, a molecular stage IV FFT, that arrived at accurate decisions without sacrificing initial information. While these FFT decision trees may seem arbitrary to an experienced oncologist at an academic site, the simplicity of their utility is essential for community practice where patients often do not get molecular testing and are not assigned proper therapy.

MET-dependent solid tumours - molecular diagnosis and targeted therapy

Attempts to develop MET-targeted therapies have historically focused on MET-expressing cancers, with limited success. Thus, MET expression in the absence of a genomic marker of MET dependence is a poor predictor of benefit from MET-targeted therapy. However, owing to the development of more sensitive methods of detecting genomic alterations, high-level MET amplification and activating MET mutations or fusions are all now known to be drivers of oncogenesis. MET mutations include those affecting the kinase or extracellular domains and those that result in exon 14 skipping. The activity of MET tyrosine kinase inhibitors varies by MET alteration category. The likelihood of benefit from MET-targeted therapies increases with increasing levels of MET amplification, although no consensus exists on the optimal diagnostic cut-off point for MET copy number gains identified using fluorescence in situ hybridization and, in particular, next-generation sequencing. Several agents targeting exon 14 skipping alterations are currently in clinical development, with promising data available from early-phase trials. By contrast, the therapeutic implications of MET fusions remain underexplored. Here we summarize and evaluate the utility of various diagnostic techniques and the roles of different classes of MET-targeted therapies in cancers with MET amplification, mutation and fusion, and MET overexpression.

Emerging therapeutic agents for advanced non-small cell lung cancer

Advanced non-small cell lung cancer (NSCLC) is the most common type of lung cancer, with a poor prognosis and no known cure. Survival time is often short because of limited treatment options. Recent advances in targeted therapy and immunotherapy have changed the landscape for the treatment of advanced NSCLC. In the last 10 years, the US Food and Drug Administration (FDA) has approved more than 17 new medications for this devastating disease and more are coming. Molecular and immunogenic testing makes personalized medicine possible for patients with advanced NSCLC. The new medications provide promising efficacy and safety resulting in improved long-term survival for a significant number of patients. In this review, we summarize the recent advances in advanced/metastatic NSCLC therapeutics with a specific focus on first in-human or early-phase I/II clinical trials. These drugs either offer better alternatives to current standard drugs in the same class or are a completely new class of drugs with novel mechanisms of action. Advances are divided into (1) targeted agents, (2) antibody-drug conjugates, and (3) immunotherapies. Finally, we present a brief review of the emerging agents and ongoing clinical studies.

Oncogene-Addicted Non-Small-Cell Lung Cancer: Treatment Opportunities and Future Perspectives

Before the introduction of tyrosine kinase inhibitors (TKIs) for a particular subgroup of patients, despite platinum-based combination chemotherapy, the majority of patients affected by non-small-cell lung cancer (NSCLC) did not live longer than one year. With deeper understanding of tumor molecular biology, treatment of NSCLC has progressively entered the era of treatment customization according to tumor molecular characteristics, as well as histology. All this information allowed the development of personalized molecular targeted therapies. A series of studies have shown that, in some cases, cancer cells can grow and survive as result of the presence of a single driver genomic abnormality. This phenomenon, called oncogene-addiction, more often occurs in adenocarcinoma histology, in non-smokers (except BRAF mutations, also frequent in smoking patients), young, and female patients. Several different driver mutations have been identified and many studies have clearly shown that upfront TKI monotherapy may improve the overall outcome of these patients. The greater efficacy of these drugs is also associated with a better tolerability and safety than chemotherapy, with fewer side effects and an extremely good compliance to treatment. The most frequent oncogene-addicted disease is represented by those tumors carrying a mutation of the epidermal growth factor receptor (EGFR). The development of first, second and third generation TKIs against EGFR mutations have dramatically changed the prognosis of these patients. Currently, osimertinib (which demonstrated to improve efficacy with a better tolerability in comparison with first-generation TKIs) is considered the best treatment option for patients affected by NSCLC harboring a common EGFR mutation. EML4-ALK-driven disease (which gene re-arrangement occurs in 3-7% of NSCLC), has demonstrated to be significantly targeted by specific TKIs, which have improved outcome in comparison with chemotherapy. To date, alectinib is considered the best treatment option for these patients, with other newer agents upcoming. Other additional driver abnormalities, such as ROS1, BRAF, MET, RET and NTRK, have been identified as a target mirroring peculiar vulnerability to specific agents. Oncogene-addicted disease typically has a low early resistance rate, but late acquired resistance always develops and therefore therapy needs to be changed when progression occurs. In this narrative review, the state of art of scientific literature about targeted therapy options in oncogene-addicted disease is summarized and critically discussed. We also aim to analyze future perspectives to maximize benefits for this subgroup of patients.

Management of Non-small Cell Lung Cancer Patients with MET Exon 14 Skipping Mutations

OPINION STATEMENT

The MET exon 14 skipping mutation is found in approximately 3% of lung adenocarcinomas and slightly more than 2% of lung squamous cell carcinomas. In recent years, more and more evidence has shown that MET inhibitors have achieved good anti-tumor effect in patients with MET exon 14 skipping mutation, suggesting that MET exon 14 skipping mutation may be a new target for NSCLC patients. Patients with positive MET exon 14 skipping mutation are recommended to be administered MET inhibitors, and crizotinib is recommended by the NCCN guideline. Due to the presence of gene amplification, second site mutation, bypass activation, and pathological type transformation, one of the inevitable problems of targeted therapy is drug resistance. If type I MET inhibitors (crizotinib, capmatinib, tepotinib, savolitinib) drug resistance is developed, type II MET inhibitors (cabozantinib, glesatinib, merestinib) can be considered.

New Targets in Lung Cancer (Excluding EGFR, ALK, ROS1)

PURPOSE OF REVIEW

Over the last two decades, the identification of targetable oncogene drivers has revolutionized the therapeutic landscape of non-small cell lung cancer (NSCLC). The extraordinary progresses made in molecular biology prompted the identification of several rare molecularly defined subgroups. In this review, we will focus on the novel and emerging actionable oncogenic drivers in NSCLC.

RECENT FINDINGS

Recently, novel oncogene drivers emerged as promising therapeutic targets besides the well-established EGFR mutations, and ALK/ROS1 rearrangements, considerably expanding the list of potential exploitable genetic aberrations. However, the therapeutic algorithm in these patients is far less defined. The identification of uncommon oncogene drivers is reshaping the diagnostic and therapeutic approach to NSCLC. The introduction of novel highly selective inhibitors is expanding the use of targeted therapies to rare and ultra-rare subsets of patients, further increasing the therapeutic armamentarium of advanced NSCLC.

Molecular Targets Beyond the Big 3

Lung cancer is a heterogeneous genomic disease. Smoking remains the primary cause. Genetic susceptibility and environmental exposures are responsible for 10% to 15% of cases. Targeted therapies improve survival in patients with tumors with oncogenic drivers. It is critical to expand our understanding of genetic alterations in non-small cell lung cancer to increase the available targeted therapies. Alterations beyond epidermal growth factor receptor (EGFR), ALK, and ROS1 exemplify lung cancer's complexity and the need for investments in precision therapy to extend patient survival and improve outcomes. This article covers genetic targets beyond EGFR, ALK and ROS1, their novel agents, challenges, and future directions.

Molecular Mechanisms of Acquired Resistance to MET Tyrosine Kinase Inhibitors in Patients with MET Exon 14-Mutant NSCLC

PURPOSE

Molecular mechanisms of acquired resistance to MET tyrosine kinase inhibitors (TKI) are poorly understood. We aimed to characterize the genomic mechanisms of resistance to type I and type II MET TKIs and their impact on sequential MET TKI therapy outcomes in patients with metastatic MET exon 14-mutant NSCLC.

EXPERIMENTAL DESIGN

Genomic alterations occurring at the time of progression on MET TKIs were studied using plasma and tissue next-generation sequencing (NGS).

RESULTS

A total of 20 patients had tissue or plasma available for analysis at the time of acquired resistance to a MET TKI. Genomic alterations known or suspected to be mechanisms of resistance were detected in 15 patients (75%). On-target acquired mechanisms of resistance, including single and polyclonal MET kinase domain mutations in codons H1094, G1163, L1195, D1228, Y1230, and high levels of amplification of the MET exon 14-mutant allele, were observed in 7 patients (35%). A number of off-target mechanisms of resistance were detected in 9 patients (45%), including KRAS mutations and amplifications in KRAS, EGFR, HER3, and BRAF; one case displayed both on- and off-target mechanisms of resistance. In 2 patients with on-target resistant mutations, switching between type I and type II MET TKIs resulted in second partial responses.

CONCLUSIONS

On-target secondary mutations and activation of bypass signaling drive resistance to MET TKIs. A deeper understanding of these molecular mechanisms can support the development of sequential or combinatorial therapeutic strategies to overcome resistance.

Antitumor activity of crizotinib in lung cancers harboring a MET exon 14 alteration

MET exon 14 alterations are oncogenic drivers of non-small-cell lung cancers (NSCLCs)1. These alterations are associated with increased MET activity and preclinical sensitivity to MET inhibition2. Crizotinib is a multikinase inhibitor with potent activity against MET3. The antitumor activity and safety of crizotinib were assessed in 69 patients with advanced NSCLCs harboring MET exon 14 alterations. Objective response rate was 32% (95% confidence interval (CI), 21-45) among 65 response-evaluable patients. Objective responses were observed independent of the molecular heterogeneity that characterizes these cancers and did not vary by splice-site region and mutation type of the MET exon 14 alteration, concurrent increased MET copy number or the detection of a MET exon 14 alteration in circulating tumor DNA. The median duration of response was 9.1 months (95% CI, 6.4-12.7). The median progression-free survival was 7.3 months (95% CI, 5.4-9.1). MET exon 14 alteration defines a molecular subgroup of NSCLCs for which MET inhibition with crizotinib is active. These results address an unmet need for targeted therapy in people with lung cancers with MET exon 14 alterations and adds to an expanding list of genomically driven therapies for oncogenic subsets of NSCLC.

First-in-Man Phase I Trial of the Selective MET Inhibitor Tepotinib in Patients with Advanced Solid Tumors

PURPOSE

Tepotinib is an oral, potent, highly selective MET inhibitor. This first-in-man phase I trial investigated the MTD of tepotinib to determine the recommended phase II dose (RP2D).

PATIENTS AND METHODS

Patients received tepotinib orally according to one of three dose escalation regimens (R) on a 21-day cycle: R1, 30-400 mg once daily for 14 days; R2, 30-315 mg once daily 3 times/week; or R3, 300-1,400 mg once daily. After two cycles, treatment could continue in patients with stable disease until disease progression or unacceptable toxicity. The primary endpoint was incidence of dose-limiting toxicity (DLT) and treatment-emergent adverse events (TEAE). Secondary endpoints included safety, tolerability, pharmacokinetics, pharmacodynamics, and antitumor effects.

RESULTS

One hundred and forty-nine patients received tepotinib (R1: n = 42; R2: n = 45; R3: n = 62). Although six patients reported DLTs [one patient in R1 (115 mg), three patients in R2 (60, 100, 130 mg), two patients in R3 (1,000, 1,400 mg)], the MTD was not reached at the highest tested dose of 1,400 mg daily. The RP2D of tepotinib was established as 500 mg once daily, supported by translational modeling data as sufficient to achieve ≥95% MET inhibition in ≥90% of patients. Treatment-related TEAEs were mostly grade 1 or 2 fatigue, peripheral edema, decreased appetite, nausea, vomiting, and lipase increase. The best overall response in R3 was partial response in two patients, both with MET overexpression.

CONCLUSIONS

Tepotinib was well tolerated with clinical activity in MET-dysregulated tumors. The RP2D of tepotinib was established as 500 mg once daily. MET abnormalities can drive tumorigenesis. This first-in-man trial demonstrated that the potent, highly selective MET inhibitor tepotinib can reduce or stabilize tumor burden and is well tolerated at doses up to 1,400 mg once daily. An RP2D of 500 mg once daily, as determined from translational modeling and simulation integrating human population pharmacokinetic and pharmacodynamic data in tumor biopsies, is being used in ongoing clinical trials.

Co-occurring Alterations in the RAS-MAPK Pathway Limit Response to MET Inhibitor Treatment in MET Exon 14 Skipping Mutation-Positive Lung Cancer

PURPOSE

Although patients with advanced-stage non-small cell lung cancers (NSCLC) harboring MET exon 14 skipping mutations (METex14) often benefit from MET tyrosine kinase inhibitor (TKI) treatment, clinical benefit is limited by primary and acquired drug resistance. The molecular basis for this resistance remains incompletely understood.

EXPERIMENTAL DESIGN

Targeted sequencing analysis was performed on cell-free circulating tumor DNA obtained from 289 patients with advanced-stage METex14-mutated NSCLC.

RESULTS

Prominent co-occurring RAS-MAPK pathway gene alterations (e.g., in KRAS, NF1) were detected in NSCLCs with METex14 skipping alterations as compared with EGFR-mutated NSCLCs. There was an association between decreased MET TKI treatment response and RAS-MAPK pathway co-occurring alterations. In a preclinical model expressing a canonical METex14 mutation, KRAS overexpression or NF1 downregulation hyperactivated MAPK signaling to promote MET TKI resistance. This resistance was overcome by cotreatment with crizotinib and the MEK inhibitor trametinib.

CONCLUSIONS

Our study provides a genomic landscape of co-occurring alterations in advanced-stage METex14-mutated NSCLC and suggests a potential combination therapy strategy targeting MAPK pathway signaling to enhance clinical outcomes.