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

Gumarontinib in patients with non-small-cell lung cancer harbouring MET exon 14 skipping mutations: a multicentre, single-arm, open-label, phase 1b/2 trial

Background

Approximately 3-4% of patients with non-small-cell lung cancer (NSCLC) have MET exon 14 (METex14) skipping mutations. We report primary results from the phase 2 stage of a phase 1b/2 study of gumarontinib, a selective, potent, oral MET inhibitor, in patients with METex14 skipping mutation-positive (METex14-positive) NSCLC.

Methods

The single-arm, multicentre, open-label, phase 2 stage of the GLORY study was conducted at 42 centres across China and Japan. Adults with locally advanced or metastatic METex14-positive NSCLC received oral gumarontinib 300 mg once daily in continuous 21-day cycles until disease progression, intolerable toxicity, or withdrawal of consent. Eligible patients had failed one or two prior lines of therapy (not including a MET inhibitor), were ineligible for/refused chemotherapy, and had no genetic alterations targetable with standard therapies. The primary endpoint was objective response rate in patients with a valid baseline tumour assessment, by blinded independent review. The study was registered at ClinicalTrials.gov (NCT04270591).

Findings

Between Aug 2, 2019 and Apr 28, 2021, 84 patients were enrolled and received gumarontinib (median follow-up 13.5 months [IQR 8.7-17.1]), at data cut-off (Apr 28, 2022) five patients whose METex14 status could not be confirmed by a central laboratory were excluded from the efficacy analysis. The objective response rate was 66% (95% CI 54-76) overall (n = 79), 71% (95% CI 55-83) in treatment-naïve patients (n = 44), and 60% (95% CI 42-76) in previously-treated patients (n = 35). The most common treatment-related adverse events (any grade) were oedema (67/84 patients, 80%) and hypoalbuminuria (32/84, 38%). Grade ≥3 treatment-emergent adverse events occurred in 45 (54%) patients. Treatment-related adverse events leading to permanent discontinuation occurred in 8% (7/84) of patients.

Interpretation

Gumarontinib monotherapy had durable antitumour activity with manageable toxicity in patients with locally advanced or metastatic METex14-positive NSCLC when used in first line or later.

Funding

Haihe Biopharma Co., Ltd. Supported in part by grants from the National Science and Technology Major Project of China for "Clinical Research of Gumarontinib, a highly selective MET inhibitor" (2018ZX09711002-011-003); the National Natural Science Foundation of China (82030045 to S.L. and 82172633 to YF.Y); Shanghai Municipal Science & Technology Commission Research Project (19411950500 to S.L.); Shanghai Shenkang Action Plan (16CR3005A to S.L.) and Shanghai Chest Hospital Project of Collaborative Innovation (YJXT20190105 to S.L.).

Clinical Relevance of Targeted Therapy and Immune-Checkpoint Inhibition in Lung Cancer

Lung cancer (LC) represents the second most diagnosed tumor and the malignancy with the highest mortality rate. In recent years, tremendous progress has been made in the treatment of this tumor thanks to the discovery, testing, and clinical approval of novel therapeutic approaches. Firstly, targeted therapies aimed at inhibiting specific mutated tyrosine kinases or downstream factors were approved in clinical practice. Secondly, immunotherapy inducing the reactivation of the immune system to efficiently eliminate LC cells has been approved. This review describes in depth both current and ongoing clinical studies, which allowed the approval of targeted therapies and immune-checkpoint inhibitors as standard of care for LC. Moreover, the present advantages and pitfalls of new therapeutic approaches will be discussed. Finally, the acquired importance of human microbiota as a novel source of LC biomarkers, as well as therapeutic targets to improve the efficacy of available therapies, was analyzed. Therapy against LC is increasingly becoming holistic, taking into consideration not only the genetic landscape of the tumor, but also the immune background and other individual variables, such as patient-specific gut microbial composition. On these bases, in the future, the research milestones reached will allow clinicians to treat LC patients with tailored approaches.

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.

Predicting response to immune checkpoint blockade in NSCLC with tumour-only RNA-seq

BACKGROUND

Targeted RNA sequencing (RNA-seq) from FFPE specimens is used clinically in cancer for its ability to estimate gene expression and to detect fusions. Using a cohort of NSCLC patients, we sought to determine whether targeted RNA-seq could be used to measure tumour mutational burden (TMB) and the expression of immune-cell-restricted genes from FFPE specimens and whether these could predict response to immune checkpoint blockade.

METHODS

Using The Cancer Genome Atlas LUAD dataset, we developed a method for determining TMB from tumour-only RNA-seq and showed a correlation with DNA sequencing derived TMB calculated from tumour/normal sample pairs (Spearman correlation = 0.79, 95% CI [0.73, 0.83]. We applied this method to targeted sequencing data from our patient cohort and validated these results against TMB estimates obtained using an orthogonal assay (Spearman correlation = 0.49, 95% CI [0.24, 0.68]).

RESULTS

We observed that the RNA measure of TMB was significantly higher in responders to immune blockade treatment (P = 0.028) and that it was predictive of response (AUC = 0.640 with 95% CI [0.493, 0.786]). By contrast, the expression of immune-cell-restricted genes was uncorrelated with patient outcome.

CONCLUSION

TMB calculated from targeted RNA sequencing has a similar diagnostic ability to TMB generated from targeted DNA sequencing.

Rare molecular subtypes of lung cancer

Oncogenes that occur in ≤5% of non-small-cell lung cancers have been defined as 'rare'; nonetheless, this frequency can correspond to a substantial number of patients diagnosed annually. Within rare oncogenes, less commonly identified alterations (such as HRAS, NRAS, RIT1, ARAF, RAF1 and MAP2K1 mutations, or ERBB family, LTK and RASGRF1 fusions) can share certain structural or oncogenic features with more commonly recognized alterations (such as KRAS, BRAF, MET and ERBB family mutations, or ALK, RET and ROS1 fusions). Over the past 5 years, a surge in the identification of rare-oncogene-driven lung cancers has challenged the boundaries of traditional clinical grade diagnostic assays and profiling algorithms. In tandem, the number of approved targeted therapies for patients with rare molecular subtypes of lung cancer has risen dramatically. Rational drug design has iteratively improved the quality of small-molecule therapeutic agents and introduced a wave of antibody-based therapeutics, expanding the list of actionable de novo and resistance alterations in lung cancer. Getting additional molecularly tailored therapeutics approved for rare-oncogene-driven lung cancers in a larger range of countries will require ongoing stakeholder cooperation. Patient advocates, health-care agencies, investigators and companies with an interest in diagnostics, therapeutics and real-world evidence have already taken steps to surmount the challenges associated with research into low-frequency drivers.

Potent antitumor activity of ensartinib in MET exon 14 skipping-mutated non-small cell lung cancer

Met proto-oncogene exon 14 skipping (METex14) mutations are targetable driver genes in approximately 3% of non-small-cell lung cancers (NSCLCs). Ensartinib, a type Ia MET inhibitor, is a multi-kinase inhibitor that has been approved for ALK-positive NSCLCs. Ensartinib was administered for compassionate use (cohort 1) and in a phase II clinical trial (cohort 2) to patients with METex14 mutant NSCLCs, with ORR as a primary endpoint. Molecular simulation was conducted to evaluate ensartinib c-MET interaction, and cell lines, patient-derived organoids (PDOs), and xenograft models were used to test the effectiveness of ensartinib. Among 29 evaluable patients, the ORR and DCR of ensartinib were 67% and 94% in cohort 1, and 73% and 91% in cohort 2. The median DoR was 6.8 months and median PFS was 6.1 months in the total population. Rash was the most common drug-related adverse event, and peripheral edema of any grade was reported in only 9% patients. Molecular simulations indicated favorable binding of ensartinib to c-MET. The kinase assay demonstrated an IC₅₀ of 7.9 nM of ensartinib against METex14 protein. In vitro, Hs746T (METex14 mutation) and EBC-1 (MET amplification) cells were sensitive to ensartinib, with IC₅₀ of 31 and 44 nM, respectively. Ensartinib exhibited comparable inhibitory effects on cell migration as crizotinib and tepotinib in both cell types. In vivo, ensartinib suppressed the growth of Hs746T cells. Ensartinib also potently inhibited the viability of PDOs. Overall, Ensartinib exhibited substantial antitumor effects against METex14 mutant NSCLCs in preclinical and clinical trials, with relatively low peripheral edema rates.

At the crossroads of immunotherapy for oncogene-addicted subsets of NSCLC

Non-small-cell lung cancer (NSCLC) has become a paradigm of precision medicine, with the discovery of numerous disease subtypes defined by specific oncogenic driver mutations leading to the development of a range of molecularly targeted therapies. Over the past decade, rapid progress has also been made in the development of immune-checkpoint inhibitors (ICIs), especially antagonistic antibodies targeting the PD-L1-PD-1 axis, for the treatment of NSCLC. Although many of the major oncogenic drivers of NSCLC are associated with intrinsic resistance to ICIs, patients with certain oncogene-driven subtypes of the disease that are highly responsive to specific targeted therapies might also derive benefit from immunotherapy. However, the development of effective immunotherapy approaches for oncogene-addicted NSCLC has been challenged by a lack of predictive biomarkers for patient selection and limited knowledge of how ICIs and oncogene-directed targeted therapies should be combined. Therefore, whether ICIs alone or with chemotherapy or even in combination with molecularly targeted agents would offer comparable benefit in the context of selected oncogenic driver alterations to that observed in the general unselected NSCLC population remains an open question. In this Review, we discuss the effects of oncogenic driver mutations on the efficacy of ICIs and the immune tumour microenvironment as well as the potential vulnerabilities that could be exploited to overcome the challenges of immunotherapy for oncogene-addicted NSCLC.

MET alterations in advanced non-small cell lung cancer

Targeting the MET pathway in advanced NSCLC has been of particular interest due to its role as both a primary oncogenic driver and secondary oncogenic driver of acquired resistance. Activation of the MET pathway can occur through several mechanisms, which can complicate the diagnostic and treatment approach. Recently, several MET-directed therapies have been developed with promising results. In this narrative review, we summarize the biology and mechanism of MET as a clinically relevant driver mutation, distinct MET alterations including diagnostic challenges, significance in the setting of acquired resistance, and novel treatment strategies in advanced NSCLC.

Optimized Detection of Unknown MET Exon 14 Skipping Mutations in Routine Testing for Patients With Non-Small-Cell Lung Cancer

PURPOSE

MET exon 14 (METex14) skipping is an actionable biomarker in non-small-cell lung cancer. However, MET variants are highly complex and diverse, and not all variants lead to exon 14 skipping. Assessing the skipping effect of unknown variants is still a key issue in molecular diagnosis.

MATERIALS AND METHODS

We retrospectively collected MET variants around exon 14 from 4,233 patients with non-small-cell lung cancer who underwent next-generation sequencing testing using DNA, as well as two published data sets.

RESULTS

Among the 4,233 patients, 44 unique variants including 29 novel variants (65.9%) were discovered from 53 patients. Notably, 31 samples (58.5%) failed RNA verification. Using RNA verification, nine novel skipping variants and five nonskipping variants were confirmed. We further used SpliceAI with the delta score cutoff of 0.315 to aid the classification of novel variants (sensitivity = 98.88% and specificity = 100%). When applied to the reported variants, we also found three wrongly classified nonskipping variants. Finally, an optimized knowledge-based interpretation procedure for clinical routine was built according to the mutation type and location, and five more skipping mutations from the 13 unknown variants were determined, which improved the population determination rate to 0.92%.

CONCLUSION

This study discovered more METex14 skipping variants and optimized an innovative approach that could be adapted for the interpretation of infrequent or novel METex14 variants timely without experimental validation.

Differences in Sustained Cellular Effects of MET inhibitors Are Driven by Prolonged Target Engagement and Lysosomal Retention

Intracellular distribution of drug compounds is dependent on physicochemical characteristics and may have a significant bearing on the extent of target occupancy and, ultimately, drug efficacy. We assessed differences in the physicochemical profiles of MET inhibitors capmatinib, crizotinib, savolitinib, and tepotinib and their effects on cell viability and MET phosphorylation under steady-state and washout conditions (to mimic an open organic system) in a human lung cancer cell line. To examine the differences of the underlying molecular mechanisms at the receptor level, we investigated the residence time at the kinase domain and the cellular target engagement. We found that the ranking of the drugs for cell viability was different under steady-state and washout conditions and that under washout conditions, tepotinib displayed the most potent inhibition of phosphorylated MET. Postwashout effects were correlated with the partitioning of the drug into acidic subcellular compartments such as lysosomes, and the tested MET inhibitors were grouped according to their ability to access lysosomes (crizotinib and tepotinib) or not (capmatinib and savolitinib). Reversible lysosomal retention may represent a valuable intracellular storage mechanism for MET inhibitors, enabling prolonged receptor occupancy in dynamic, open-physiologic systems and may act as a local drug reservoir. The use of washout conditions to simulate open systems and investigate intracellular drug distribution is a useful characterization step that deserves further investigation. SIGNIFICANCE STATEMENT: Generally, determination of potency and receptor occupancy is performed under steady-state conditions. In vivo conditions are more complex due to concentration differences between compartments and equilibrium processes. Experiments under steady state cannot explore effects such as sustained target inhibition. This study has shown that differences between MET inhibitors are observable by applying washout conditions to in vitro assays. This important finding applies to most compound classes and may inspire readers to rethink their assay designs in the future.

Updated Views in Targeted Therapy in the Patient with Non-Small Cell Lung Cancer

Non-small cell lung cancer (NSCLC) is the most frequent form of lung cancer and represents a set of histological entities that have an ominous long-term prognosis, for example, adenocarcinoma, squamous carcinoma and large cell carcinoma. Both small cell and non-small cell lung cancer are the main causes of oncological death and the oncological diseases with the highest incidence worldwide. With regard to clinical approaches for NSCLC, several advances have been achieved in diagnosis and treatment; the analysis of different molecular markers has led to the development of new targeted therapies that have improved the prognosis for selected patients. Despite this, most patients are diagnosed in an advanced stage, presenting a limited life expectancy with an ominous short-term prognosis. Numerous molecular alterations have been described in recent years, allowing for the development of therapies directed against specific therapeutic targets. The correct identification of the expression of different molecular markers has allowed for the individualization of treatment throughout the disease course, expanding the available therapeutic arsenal. The purpose of this article is to summarize the main characteristics of NSCLC and the advances that have occurred in the use of targeted therapies, thus explaining the limitations that have been observed in the management of this disease.

New Targeted Therapy for Non-Small Cell Lung Cancer

Lung cancer ranks first in cancer mortality in Korea and cancer incidence in Korean men. More than half of Korean lung cancer patients undergo chemotherapy, including adjuvant therapy. Cytotoxic agents, targeted therapy, and immune checkpoint inhibitors are used in chemotherapy according to the biopsy and genetic test results. Among chemotherapy, the one that has developed rapidly is targeted therapy. The National Comprehensive Cancer Network (NCCN) guidelines have been updated recently for targeted therapy of multiple gene mutations, and targeted therapy is used not only for chemotherapy but also for adjuvant therapy. While previously targeted therapies have been developed for common genetic mutations, recently targeted therapies have been developed to overcome uncommon mutations or drug resistance that have occurred since previous targeted therapy. Therefore, this study describes recent, rapidly developing targeted therapies.

Pulmonary embolism and bradycardia in a NSCLC patient treated with crizotinib for a rare mutation

INTRODUCTION

Lung cancer is a major global health problem because of its high incidence and mortality. Targeted therapies have transformed treatment of driver-mutated metastatic non-small cell lung cancer (NSCLC). Nevertheless, recent studies demonstrated that cardiovascular disease (CVD) was the second leading cause of mortality in cancer survivors now, management of patients' cardiovascular health during the course of anticancer therapy has become a great challenge faced by the oncologists. Anticancer related cardiovascular (CV) complications are not limited to traditional chemotherapy, but are also increasingly recognized in targeted therapy.

CASE REPORT

We present a case of pulmonary embolism (PE) and bradycardia in a 91-year-old NSCLC patient treated with crizotinib for a rare MET Y1003S mutation. To our knowledge, this is the second report to show antitumor response of crizotinib in lung cancer patients with such a rare mutation. However, the patient complained chest tightness and shortness of breath after a month of standard dose crizotinib therapy. Non-invasive examination revealed new onset bradycardia and PE.

MANAGEMENT & OUTCOME

Such clinical manifestations were associated with targeted therapy-related CV toxicity, on which the emerging discipline cardio-oncology focused, and a multidisciplinary investigation and treatment was conducted.

DISCUSSION

This case highlights the CV adverse events of novel therapies and the current challenges to be tackled in cardio-oncology.

[Research Progresses in the Treatment of NSCLC with MET Gene Variants: A Riview]

Mesenchymal-epithelial transition factor (MET) has long been considered as the most crucial and promising driver gene in the occurrence and development of non-small cell lung cancer (NSCLC), except for epidermal growth factor receptor (EGFR), anaplastic lymphoma kinase (ALK), and c-ROS oncogene 1 receptor tyrosine kinase (ROS1). In recent years, therapeutic drugs targeting MET have been continuously developed and applied in clinical practice. First, the curative effect of NSCLC patients with MET exon 14 skipping mutations has been further improved. In addition, when MET amplification occurs after resistance to EGFR tyrosine kinase inhibitors (EGFR-TKIs) in patients with advanced EGFR-mutant NSCLC, the combination of MET-TKIs and EGFR-TKIs has brought significant survival benefits and many other advances. This article reviews the treatment progress of NSCLC patients with different types of MET variants under different circumstances, which provides reference for the selection of clinical treatment strategies.
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Oncogenic KRAS alters splicing factor phosphorylation and alternative splicing in lung cancer

BACKGROUND

Alternative RNA splicing is widely dysregulated in cancers including lung adenocarcinoma, where aberrant splicing events are frequently caused by somatic splice site mutations or somatic mutations of splicing factor genes. However, the majority of mis-splicing in cancers is unexplained by these known mechanisms. We hypothesize that the aberrant Ras signaling characteristic of lung cancers plays a role in promoting the alternative splicing observed in tumors.

METHODS

We recently performed transcriptome and proteome profiling of human lung epithelial cells ectopically expressing oncogenic KRAS and another cancer-associated Ras GTPase, RIT1. Unbiased analysis of phosphoproteome data identified altered splicing factor phosphorylation in KRAS-mutant cells, so we performed differential alternative splicing analysis using rMATS to identify significantly altered isoforms in lung epithelial cells. To determine whether these isoforms were uniquely regulated by KRAS, we performed a large-scale splicing screen in which we generated over 300 unique RNA sequencing profiles of isogenic A549 lung adenocarcinoma cells ectopically expressing 75 different wild-type or variant alleles across 28 genes implicated in lung cancer.

RESULTS

Mass spectrometry data showed widespread downregulation of splicing factor phosphorylation in lung epithelial cells expressing mutant KRAS compared to cells expressing wild-type KRAS. We observed alternative splicing in the same cells, with 2196 and 2416 skipped exon events in KRASG12V and KRASQ61H cells, respectively, 997 of which were shared (p < 0.001 by hypergeometric test). In the high-throughput splicing screen, mutant KRAS induced the greatest number of differential alternative splicing events, second only to the RNA binding protein RBM45 and its variant RBM45M126I. We identified ten high confidence cassette exon events across multiple KRAS variants and cell lines. These included differential splicing of the Myc Associated Zinc Finger (MAZ). As MAZ regulates expression of KRAS, this splice variant may be a mechanism for the cell to modulate wild-type KRAS levels in the presence of oncogenic KRAS.

CONCLUSION

Proteomic and transcriptomic profiling of lung epithelial cells uncovered splicing factor phosphorylation and mRNA splicing events regulated by oncogenic KRAS. These data suggest that in addition to widespread transcriptional changes, the Ras signaling pathway can promote post-transcriptional splicing changes that may contribute to oncogenic processes.

Crizotinib efficacy and safety in patients with advanced NSCLC harboring MET alterations: A real-life data of Turkish Oncology Group

Crizotinib is a multikinase inhibitor, effective in non-small cell lung cancer (NSCLC) harboring mesenchymal-epidermal transition (MET) alterations. Although small prospective studies showed efficacy and safety of crizotinib in NSCLC with MET alterations, there is limited real-life data. Aim of this study is to investigate real-life efficacy and safety of crizotinib in patients with advanced NSCLC harboring MET alterations. This was a retrospective, multicenter (17 centers) study of Turkish Oncology Group. Patients' demographic, histological data, treatment, response rates, survival outcomes, and toxicity data were collected. Outcomes were presented for the study population and compared between MET alteration types. Total of 62 patients were included with a median age of 58.5 (range, 26-78). Major histological type was adenocarcinoma, and 3 patients (4.8%) had sarcomatoid component. The most common MET analyzing method was next generation sequencing (90.3%). MET amplification and mutation frequencies were 53.2% (n = 33) and 46.8% (n = 29), respectively. Overall response rate and disease control rate were 56.5% and 74.2% in whole study population, respectively. Median progression free survival (PFS) was 7.2 months (95% confidence interval [CI]: 3.8-10.5), and median overall survival (OS) was 18.7 months (95% CI: 13.7-23.7), regardless of treatment line. Median PFS was 6.1 months (95% CI: 5.6-6.4) for patients with MET amplification, whereas 14.3 months (95% CI: 6.7-21.7) for patients with MET mutation (P = .217). Median PFS was significantly longer in patients who have never smoked (P = .040), have good performance score (P < .001), and responded to the treatment (P < .001). OS was significantly longer in patients with MET mutation (25.6 months, 95% CI: 15.9-35.3) compared to the patients with MET amplification (11.0 months; 95% CI: 5.2-16.8) (P = .049). In never-smokers, median OS was longer than smoker patients (25.6 months [95% CI: 11.8-39.3] vs 16.5 months [95% CI: 9.3-23.6]; P = .049). The most common adverse effects were fatigue (50%), peripheral edema (21%), nausea (29%) and diarrhea (19.4%). Grade 3 or 4 adverse effects were observed in 6.5% of the patients. This real-life data confirms efficacy and safety of crizotinib in the treatment of advanced NSCLC harboring MET alteration.

Molecular pathways, resistance mechanisms and targeted interventions in non-small-cell lung cancer

Lung cancer is the leading cause of cancer-related mortality worldwide. The discovery of tyrosine kinase inhibitors effectively targeting EGFR mutations in lung cancer patients in 2004 represented the beginning of the precision medicine era for this refractory disease. This great progress benefits from the identification of driver gene mutations, and after that, conventional and new technologies such as NGS further illustrated part of the complex molecular pathways of NSCLC. More targetable driver gene mutation identification in NSCLC patients greatly promoted the development of targeted therapy and provided great help for patient outcomes including significantly improved survival time and quality of life. Herein, we review the literature and ongoing clinical trials of NSCLC targeted therapy to address the molecular pathways and targeted intervention progress in NSCLC. In addition, the mutations in EGFR gene, ALK rearrangements, and KRAS mutations in the main sections, and the less common molecular alterations in MET, HER2, BRAF, ROS1, RET, and NTRK are discussed. The main resistance mechanisms of each targeted oncogene are highlighted to demonstrate the current dilemma of targeted therapy in NSCLC. Moreover, we discuss potential therapies to overcome the challenges of drug resistance. In this review, we manage to display the current landscape of targetable therapeutic patterns in NSCLC in this era of precision medicine.

Landscape of Savolitinib Development for the Treatment of Non-Small Cell Lung Cancer with MET Alteration-A Narrative Review

Non-small cell lung cancer (NSCLC) is increasingly being treated with targeted therapies. Savolitinib (Orpathys^®) is highly selective mesenchymal epithelial transition (MET)-tyrosine kinase inhibitor (TKI), which is conditionally approved in China for advanced NSCLC with MET exon 14 skipping mutations (METex14). This article summarizes the clinical development of savolitinib, as a monotherapy in NSCLC with METex14 mutation and in combination with epidermal growth factor receptor (EGFR) inhibitor in post EGFR-TKI resistance NSCLC due to MET-based acquired resistance. Preclinical models demonstrated anti-tumor activities in MET-driven cancer cell line and xenograft tumor models. The Phase Ia/Ib study established an optimized, recommended phase II dose in Chinese NSCLC patients, while TATTON study of savolitinib plus osimertinib in patients with EGFR mutant, MET-amplified and TKI-progressed NSCLC showed beneficial efficacy with acceptable safety profile. In a pivotal phase II study, Chinese patients with pulmonary sarcomatoid carcinoma, brain metastasis and other NSCLC subtype positive for METex14 mutation showed notable responses and acceptable safety profile with savolitinib. Currently, results from ongoing clinical trials are eagerly anticipated to confirm the efficacious and safety benefits of savolitinib as monotherapy and in combination with EGFR-TKI in acquired resistance setting in advanced NSCLC and its subtypes with MET alterations.

Management and Treatment of Non-small Cell Lung Cancer with MET Alteration and Mechanisms of Resistance

OPINION STATEMENT

MET-driven tumors are a heterogenous group of non-small cell lung cancers (NSCLC) with activating mutations. Pathologic activation of MET can be achieved with increased number of gene copies overexpression, or decreased protein degradation through several mechanisms, including mutations, amplifications, or fusions. Besides its role as primary driver, MET activation might also mediate resistance to kinase inhibitors in NSCLC with various other actionable alterations. While checkpoint inhibitors have modest efficacy in MET-driven tumors, several approaches of targeted blockade are available. Among them the most promising are small tyrosine kinase inhibitors, antibody-drug conjugates, and bispecific antibodies. Unfortunately, resistance is virtually inevitable. Resistance to small kinase inhibitors might be mediated by kinase domain mutations or activation of shunting cascades. Various resistance mechanisms might be present in one patient, making it overcoming an unresolved problem.

Asian Thoracic Oncology Research Group (ATORG) Expert Consensus Statement on MET Alterations in NSCLC: Diagnostic and Therapeutic Considerations

Non-small cell lung cancer (NSCLC) is a heterogeneous disease, with many oncogenic driver mutations, including de novo mutations in the Mesenchymal Epithelial Transition (MET) gene (specifically in Exon 14 [ex14]), that lead to tumourigenesis. Acquired alterations in the MET gene, specifically MET amplification is also associated with the development of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) resistance in patients with EGFR-mutant NSCLC. Although MET has become an actionable biomarker with the availability of MET-specific inhibitors in selected countries, there is differential accessibility to diagnostic platforms and targeted therapies across countries in Asia-Pacific (APAC). The Asian Thoracic Oncology Research Group (ATORG), an interdisciplinary group of experts from Australia, Hong Kong, Japan, Korea, Mainland China, Malaysia, the Philippines, Singapore, Taiwan, Thailand and Vietnam, discussed testing for MET alterations and considerations for using MET-specific inhibitors at a consensus meeting in January 2022, and in subsequent offline consultation. Consensus recommendations are provided by the ATORG group to address the unmet need for standardised approaches to diagnosing MET alterations in NSCLC and for using these therapies. MET inhibitors may be considered for first-line or second or subsequent lines of treatment for patients with advanced and metastatic NSCLC harbouring MET ex14 skipping mutations; MET ex14 testing is preferred within multi-gene panels for detecting targetable driver mutations in NSCLC. For patients with EGFR-mutant NSCLC and MET amplification leading to EGFR TKI resistance, enrolment in combination trials of EGFR TKIs and MET inhibitors is encouraged.

PD-1/PD-L1 inhibitor activity in patients with gene-rearrangement positive non-small cell lung cancer-an IMMUNOTARGET case series

Background

Prior IMMUNOTARGET registry data had suggested that responses to immune [anti PD(L)1] monotherapy in gene-arranged non-small cell lung cancer (NSCLC) were rare or absent, depending on the specific oncogene.

Methods

IMMUNOTARGET sites reporting prior registry data or new individual cases of gene rearranged NSCLC seeming to benefit from immune monotherapy were explored in detail looking to both validate their diagnosis of a functional gene rearrangement and to look for features potentially differentiating them from other such cases associated with low response rates.

Results

Five cases of NSCLC with a gene rearrangement with reported responses or prolonged stabilization from immune monotherapy were identified in total. All had little or no prior smoking history and had programmed death-ligand 1 (PD-L1) values ranging from zero to 100%. A confirmed rearrangement partner was reported in only 2 of the cases (CD74-ROS1 and KIF5B-RET), however in one of the other three cases [analplastic lymophoma kinase (ALK)], significant benefit from a relevant prior targeted therapy was noted, also consistent with the rearrangement status being correctly assigned.

Conclusions

Not all driver oncogene subtypes of NSCLC are equally responsive to immune monotherapy, however even among patients with well-validated gene rearranged NSCLC which has traditionally been considered immune hyporesponsive, objective responses can occur. Additional explorations of the features associated with and underlying the immune hypo-responsiveness of most, but not all, cases of gene-rearranged NSCLC are required.

Malignant neoplasm of the bronchi and lung: Russian clinical guidelines

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MET Signaling Pathways, Resistance Mechanisms, and Opportunities for Target Therapies

The MET gene, known as MET proto-oncogene receptor tyrosine kinase, was first identified to induce tumor cell migration, invasion, and proliferation/survival through canonical RAS-CDC42-PAK-Rho kinase, RAS-MAPK, PI3K-AKT-mTOR, and β-catenin signaling pathways, and its driver mutations, such as MET gene amplification (METamp) and the exon 14 skipping alterations (METex14), activate cell transformation, cancer progression, and worse patient prognosis, principally in lung cancer through the overactivation of their own oncogenic and MET parallel signaling pathways. Because of this, MET driver alterations have become of interest in lung adenocarcinomas since the FDA approval of target therapies for METamp and METex14 in 2020. However, after using MET target therapies, tumor cells develop adaptative changes, favoring tumor resistance to drugs, the main current challenge to precision medicine. Here, we review a link between the resistance mechanism and MET signaling pathways, which is not only limited to MET. The resistance impacts MET parallel tyrosine kinase receptors and signals shared hubs. Therefore, this information could be relevant in the patient's mutational profile evaluation before the first target therapy prescription and follow-up to reduce the risk of drug resistance. However, to develop a resistance mechanism to a MET inhibitor, patients must have access to the drugs. For instance, none of the FDA approved MET inhibitors are registered as such in Chile and other developing countries. Constant cross-feeding between basic and clinical research will thus be required to meet future challenges imposed by the acquired resistance to targeted therapies.

Refining patient selection of MET-activated non-small cell lung cancer through biomarker precision

Dysregulated MET signaling plays an important role in lung oncogenesis, tumor growth and invasiveness. It may occur through various mechanisms, such as MET overexpression or gene amplification or mutation, all of which can be detected by specific methods. The utility of MET overexpression as a biomarker remains unclear due to discrepancies in its occurrence and non-standardized cut-off thresholds. MET exon 14 skipping mutation (METex14) was established as a strong predictor of response to selective MET tyrosine kinase inhibitors (TKIs), and clinical trial results in patients with non-small cell lung cancer (NSCLC) harboring METex14 led to the approval of capmatinib and tepotinib by regulatory agencies worldwide. MET amplification is an emerging biomarker, with clinical data indicating an association between MET gene copy number and response to MET-TKIs. Additionally, MET amplification represents an important mechanism of resistance to TKIs in oncogene-driven NSCLC. The identification of molecular alterations for which targeted therapies are available is important, and high-throughput next-generation sequencing techniques can provide information on multiple genes at the same time, helping to provide valuable predictive information for oncogene-driven cancers. This review summarizes the current methods used for the detection of METex14, MET amplification and MET overexpression, and discusses the evidence for the use of MET-TKIs in patients with NSCLC with MET dysregulation. We discuss the practical challenges that impact the use of METex14 in the clinic and the evidence gaps that need to be addressed to validate additional genomic markers for MET-dependent cancers.

Patient attrition in Molecular Tumour Boards: a systematic review

BACKGROUND

Molecular Tumour Boards (MTBs) were created with the purpose of supporting clinical decision-making within precision medicine. Though in use globally, reporting on these meetings often focuses on the small percentages of patients that receive treatment via this process and are less likely to report on, and assess, patients who do not receive treatment.

METHODS

A literature review was performed to understand patient attrition within MTBs and barriers to patients receiving treatment. A total of 51 papers were reviewed spanning a 6-year period from 11 different countries.

RESULTS

In total, 20% of patients received treatment through the MTB process. Of those that did not receive treatment, the main reasons were no mutations identified (27%), no actionable mutations (22%) and clinical deterioration (15%). However, data were often incomplete due to inconsistent reporting of MTBs with only 55% reporting on patients having no mutations, 55% reporting on the presence of actionable mutations with no treatment options and 59% reporting on clinical deterioration.

DISCUSSION

As patient attrition in MTBs is an issue which is very rarely alluded to in reporting, more transparent reporting is needed to understand barriers to treatment and integration of new technologies is required to process increasing omic and treatment data.

Circulating tumour DNA biomarkers in savolitinib-treated patients with non-small cell lung cancer harbouring MET exon 14 skipping alterations: a post hoc analysis of a pivotal phase 2 study

Background

Savolitinib, a selective MET inhibitor, showed efficacy in patients with non-small cell lung cancer (NSCLC), including pulmonary sarcomatoid carcinoma (PSC), harbouring MET exon 14 skipping alteration (METex14).

Objective

To analyse post hoc, the association between circulating tumour DNA (ctDNA) biomarkers and clinical outcomes, including resistance, with savolitinib.

Design

A multicentre, single-arm, open-label phase 2 study.

Methods

All enrolled patients with baseline plasma samples were included. Outcomes were objective response rate (ORR), progression-free survival (PFS) and overall survival (OS) by baseline METex14 and post-treatment clearance, coexisting gene alterations at baseline and disease progression.

Results

Among 66 patients with baseline ctDNA sequencing, 46 (70%) had detectable METex14. Frequent coexisting baseline gene alterations included TP53 and POT1 mutations. Patients with detectable baseline METex14 exhibited worse PFS [hazard ratio (HR), 1.77; 95% confidence interval (CI), 0.88-3.57; p = 0.108] and OS (HR, 3.26; 95% CI, 1.35-7.89; p = 0.006) than those without, despite showing a numerically higher ORR. Among 24 patients with baseline detectable METex14 and evaluable postbaseline samples, 13 achieved METex14 clearance post-treatment. Median time to first clearance was 1.3 months (range, 0.7-1.5). METex14 post-treatment clearance was associated with better ORR (92.3%; 95% CI, 64.0-99.8 versus 36.4%; 95% CI, 10.9-69.2; p = 0.0078), PFS (HR, 0.44; 95% CI, 0.2-1.3; p = 0.1225) and OS (HR, 0.31; 95% CI, 0.1-1.0; p = 0.0397) versus non-clearance. Among 22 patients with disease progression, 10 acquired pathway alterations (e.g. in RAS/RAF and PI3K/PTEN) alone or with secondary MET mutations (D1228H/N and Y1230C/H/S).

Conclusion

ctDNA biomarkers may allow for longitudinal monitoring of clinical outcomes with savolitinib in patients with METex14-positive PSC and other NSCLC subtypes. Specifically, undetectable baseline METex14 or post-treatment clearance may predict favourable clinical outcomes, while secondary MET mutations and other acquired gene alterations may explain resistance to savolitinib.

Registration

The trial was registered with ClinicalTrials.gov (NCT02897479) on 13 September 2016.

MET-targeted therapies for the treatment of non-small-cell lung cancer: A systematic review and meta-analysis

BACKGROUND

Dysregulation of the mesenchymal epithelial transition (MET) pathway contributes to poor clinical outcomes in patients with non-small cell lung cancer (NSCLC). Numerous clinical trials are currently investigating several therapies based on modulation of the MET pathway.

OBJECTIVES

This study aimed to systematically evaluate the activity and safety of MET inhibitors in patients with NSCLC.

METHODS

We searched PubMed, Embase, and the Cochrane Library from inception to June 02, 2022. The objective response rate (ORR) and disease control rate (DCR) were extracted as the main outcomes and pooled using the weighted mean proportion with fixed- or random-effects models in cases of significant heterogeneity (I 2>50%). Safety analysis was performed based on adverse events reported in all studies.

RESULTS

Eleven studies (882 patients) were included in the meta-analysis. The pooled ORR was 28.1% (95% confidence interval [CI], 0.223-0.354), while the pooled DCR was 69.1% (95% CI, 0.631-0.756). ORRs were higher for tepotinib (44.7% [95% CI, 0.365-0.530]) and savolitinib (42.9% [95% CI, 0.311-0.553]) than for other types of MET inhibitors. Patients with NSCLC with exon 14 skipping exhibited higher ORRs (39.3% (95% CI, 0.296-0.522)) and DCRs (77.8% (95% CI, 0.714-0.847)) than those with MET protein overexpression or amplification. Intracranial response rate and intracranial disease control rates were 40.1% (95% CI, 0.289-0.556) and 95.4% (95% CI, 0.892-0.100), respectively. Adverse events were mild (grade 1 to 2) in 87.2% of patients. Common adverse events above grade 3 included lower extremity edema (3.5% [95% CI, 0.027-0.044]), alanine aminotransferase (ALT) elevation (2.4% [95% CI, 0.014-0.033]), and lipase elevation (2.2% [95% CI, 0.016-0.031]).

CONCLUSION

MET inhibitors, which exhibited a satisfactory safety profile in the current study, may become a new standard of care for addressing MET dysregulation in patients with advanced or metastatic NSCLC, and even in those with brain metastases, particularly tepotinib, savolitinib and capmatinib. Further randomized trials are required to establish standard predictive biomarkers for MET therapies and to compare the effects of different MET inhibitors in NSCLC with MET dysregulation.

Meeting an un-MET need: Targeting MET in non-small cell lung cancer

The MET pathway can be activated by MET exon 14 skipping mutations, gene amplification, or overexpression. Mutations within this pathway carry a poor prognosis for patients with non-small cell lung cancer (NSCLC). MET exon 14 skipping mutations occur in 3-4% of patients with NSCLC, while MET amplifications are found in 1-6% of patients. The most effective method for detection of MET amplification is fluorescent in situ hybridization (FISH) and of MET exon 14 skipping mutations is RNA-based next generation sequencing (NGS). Immunohistochemistry (IHC) is an alternative method of diagnosis but is not as reliable. Early studies of MET tyrosine kinase inhibitors (TKIs) demonstrated limited clinical benefit. However, newer selective MET TKIs, such as capmatinib and tepotinib, have improved efficacy. Both drugs have an acceptable safety profile with the most common treatment-related adverse event being peripheral edema. One of the most frequent resistance mechanisms to EGFR inhibition with osimertinib is MET amplification. There is interest in combining EGFR inhibition plus MET inhibition in an attempt to target this resistance mechanism. Additional ways of targeting MET alterations are currently under investigation, including the bi-specific antibody amivantamab. Additional research is needed to further understand resistance mechanisms to MET inhibition. There is limited research into the efficacy of immune checkpoint inhibition for MET-altered NSCLC, though some data suggests decreased efficacy compared with wild-type patients and increased toxicity associated with the combination of immunotherapy and MET TKIs. Future directions for research will include combination clinical trials and understanding rational combinations for MET alterations.

Integrative genomic analysis of drug resistance in MET exon 14 skipping lung cancer using patient-derived xenograft models

Background

Non-small cell lung cancer (NSCLC) driven by MET exon 14 skipping (METex14) occurs in 3-4% of NSCLC cases and defines a subset of patients with distinct characteristics. While MET targeted therapy has led to strong clinical results in METex14 patients, acquired drug resistance seemed to be unavoidable during treatment. Limited information is available regarding acquired resistance during MET targeted therapy, nor has there been any report on such patient-derived xenografts (PDXs) model facilitating the research.

Methods

We describe a patient case harboring METex14 who exhibited drug resistance after treatment with crizotinib. Subcutaneous xenografts were generated from pretreatment and post-resistance patient specimens. PDX mice were then treated with MET inhibitors (crizotinib and tepotinib) and EGFR-MET bispecific antibodies (EMB-01 and amivantamab) to evaluate their drug response in vivo. DNA and RNA sequencing analysis was performed on patient tumor specimens and matching xenografts.

Results

PDXs preserved most of the histological and molecular profiles of the parental tumors. Drug resistance to MET targeted therapy was confirmed in PDX models through in vivo drug analysis. Newly acquired MET D1228H mutations and EGFR amplificated were detected in patient-resistant tumor specimens. Although the mutations were not detected in the PDX, EGFR overexpression was observed in RNA sequencing analysis indicating possible off-target resistance through the EGFR bypass signaling pathway. As expected, EGFR-MET bispecific antibodies overcome drug resistant in the PDX model.

Conclusions

We detected a novel MET splice site deletion mutation that could lead to METex14. We also established and characterized a pair of METex14 NSCLC PDXs, including the first crizotinib resistant METex14 PDX. And dual inhibition of MET and EGFR might be a therapeutic strategy for EGFR-driven drug resistance METex14 lung cancer.

Non-small cell lung cancer in China

In China, lung cancer is a primary cancer type with high incidence and mortality. Risk factors for lung cancer include tobacco use, family history, radiation exposure, and the presence of chronic lung diseases. Most early-stage non-small cell lung cancer (NSCLC) patients miss the optimal timing for treatment due to the lack of clinical presentations. Population-based nationwide screening programs are of significant help in increasing the early detection and survival rates of NSCLC in China. The understanding of molecular carcinogenesis and the identification of oncogenic drivers dramatically facilitate the development of targeted therapy for NSCLC, thus prolonging survival in patients with positive drivers. In the exploration of immune escape mechanisms, programmed cell death protein 1 (PD-1)/programmed death-ligand 1 (PD-L1) inhibitor monotherapy and PD-1/PD-L1 inhibitor plus chemotherapy have become a standard of care for advanced NSCLC in China. In the Chinese Society of Clinical Oncology's guidelines for NSCLC, maintenance immunotherapy is recommended for locally advanced NSCLC after chemoradiotherapy. Adjuvant immunotherapy and neoadjuvant chemoimmunotherapy will be approved for resectable NSCLC. In this review, we summarized recent advances in NSCLC in China in terms of epidemiology, biology, molecular pathology, pathogenesis, screening, diagnosis, targeted therapy, and immunotherapy.

MET alterations in NSCLC—Current Perspectives and Future Challenges

Targeted therapies have revolutionized the treatment and improved the outcome for oncogene-driven NSCLC and an increasing number of oncogenic driver therapies have become available. For MET-dysregulated NSCLC (especially MET exon 14 skipping mutations and MET-amplifications, which is one of the most common bypass mechanisms of resistance in oncogene-addicted NSCLC), several anti-MET-targeted therapies have been approved recently (MET exon 14 skipping mutation) and multiple others are in development. In this narrative review, we summarize the role of MET as an oncogenic driver in NSCLC, discuss the different testing methods for exon 14 skipping mutations, gene amplification, and protein overexpression, and review the existing data and ongoing clinical trials regarding targeted therapies in MET-altered NSCLC. As immunotherapy with or without chemotherapy has become the standard of care for advanced NSCLC, immunotherapy data for MET-dysregulated NSCLC are put into perspective. Finally, we discuss future challenges in this rapidly evolving landscape.

MET alterations in advanced pulmonary sarcomatoid carcinoma

Pulmonary sarcomatoid carcinoma (PSC) is a rare subset of NSCLC that accounts for about 0.5-1% of all primary lung carcinoma, and its malignant biological behavior is more aggressive than other pathological types of lung cancer. Recent studies have reported a variety of gene mutations associated with the occurrence, development and treatment of PSC, especially the mesenchymal-epithelial transition (MET) proto-oncogene alterations, including the exon 14 (METex14) skipping mutations as well as the amplification and overexpression of MET gene, which are associated with molecularly targeted therapy for PSC. METex14 skipping mutation is the most common and well-studied mutation type, occurring in about 22-31.8% of PSC patients, while the prevalence of MET amplification is reported as 4.8-13.6% and MET ovexpression is about 20.2%. Molecular pathology tests, including IHC and NGS, are valuable in determining the prognosis of patients with PSC and helping to determine the treatment. The existing clinical data have confirmed the efficacy of MET-TKI in PSC patients with MET alteration, among which the clinical study of Savolitinib has enrolled the largest proportion of PSC patients and achieved relatively good efficacy, but more clinical researches are still needed. The multi-disciplinary team may maximize the optimal treatment options for patients with the advanced PSC.

Mutational Landscape and Expression of PD-L1 in Patients with Non-Small Cell Lung Cancer Harboring Genomic Alterations of the MET gene

Background

Mesenchymal-to-epithelial transition (MET) exon 14 skipping mutations and MET gene amplification occur in 3–5% of non-small cell lung cancer (NSCLC) patients. Tyrosine kinase inhibitors (TKIs) targeting MET alterations have shown promising results in these patients.

Objective

The aim of this study was to describe the genomic profile, PD-L1 expression and clinicopathological features of MET dysregulated NSCLC.

Patients and Methods

We identified 188 patients with advanced-stage NSCLC with data on MET expression by immunohistochemistry (IHC). IHC for PD-L1 expression was performed in 131 patient samples, and next-generation sequencing (NGS) analysis was performed in 109 patient samples.

Results

MET exon 14 skipping alterations were identified in 16 (14.7%) samples, MET amplifications with cut-off ≥4 copy number variations were identified in 11 (10.1%) samples, and an oncogenic MET mutation (MET p.D1228N) was identified in 1 (0.9%) sample. 12/15 tumors (80.0%) harboring MET exon 14 alterations and 7/11 (63.6%) MET-amplified tumors expressed PD-L1 in ≥1% of tumor cells. Tumors harboring MET exon 14 skipping alterations expressed PD-L1 more frequently than MET wild-type IHC-positive tumors (p = 0.045). Twenty-five percent of MET exon 14-altered cases and 33% of MET-amplified cases harbored potentially targetable oncogenic co-mutations in KRAS, BRAF, and EGFR. The most frequent co-occurring mutations in all MET-altered tumors were TP53, KRAS, BRAF, and CDK4.

Conclusions

We demonstrated that MET exon 14 skipping alterations and MET amplification are not mutually exclusive to other oncogenic co-mutations, and report the association of genomic MET alterations with PD-L1 expression. Since genomic MET alterations are emerging targets requiring upfront treatment, optimal understanding of the co-mutational landscape for this patient population is needed.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11523-022-00918-6.

Liquid Biopsy Analysis as a Tool for TKI-Based Treatment in Non-Small Cell Lung Cancer

The treatment of non-small cell lung cancer (NSCLC) has recently evolved with the introduction of targeted therapy based on the use of tyrosine kinase inhibitors (TKIs) in patients with certain gene alterations, including EGFR, ALK, ROS1, BRAF, and MET genes. Molecular targeted therapy based on TKIs has improved clinical outcomes in a large number of NSCLC patients with advanced disease, enabling significantly longer progression-free survival (PFS). Liquid biopsy is an increasingly popular diagnostic tool for treating TKI-based NSCLC. The studies presented in this article show that detection and analysis based on liquid biopsy elements such as circulating tumor cells (CTCs), cell-free DNA (cfDNA), exosomes, and/or tumor-educated platelets (TEPs) can contribute to the appropriate selection and monitoring of targeted therapy in NSCLC patients as complementary to invasive tissue biopsy. The detection of these elements, combined with their molecular analysis (using, e.g., digital PCR (dPCR), next generation sequencing (NGS), shallow whole genome sequencing (sWGS)), enables the detection of mutations, which are required for the TKI treatment. Despite such promising results obtained by many research teams, it is still necessary to carry out prospective studies on a larger group of patients in order to validate these methods before their application in clinical practice.

Management of Peripheral Edema in Patients with MET Exon 14-Mutated Non-small Cell Lung Cancer Treated with Small Molecule MET Inhibitors

Small molecule mesenchymal-epithelial transition (MET) inhibitors, such as crizotinib, capmatinib, and tepotinib, are treatment options for metastatic non-small cell lung cancer (NSCLC) in adult patients whose tumors have a mutation that leads to MET exon 14 skipping. In clinical trials, these MET inhibitors were associated with a high incidence of peripheral edema, although this was generally mild-to-moderate in severity. There is limited information about the mechanism involved in MET inhibitor-induced peripheral edema. Perturbation of hepatocyte growth factor (HGF)/MET signaling may disrupt the permeability balance in the vascular endothelium and thus promote edema development. Another potential mechanism is through effects on renal function, although this is unlikely to be the primary mechanism. Because edema is common in cancer patients and may not necessarily be caused by the cancer treatment, or other conditions that have similar symptoms to peripheral edema, a thorough assessment is required to ascertain the underlying cause. Before starting MET-inhibitor therapy, patients should be educated about the possibility of developing peripheral edema. Patient limb volume should be measured before initiating treatment, to aid assessment if symptoms develop. Since the exact mechanism of MET inhibitor-induced edema is unknown, management is empiric, with common approaches including compression stockings, specific exercises, massage, limb elevation, and/or diuretic treatment. Although not usually required, discontinuation of MET inhibitor treatment generally resolves peripheral edema. Early diagnosis and management, as well as patient information and education, are vital to decrease the clinical burden associated with edema, and to reinforce capmatinib treatment adherence.

Case report: Prompt response to radiotherapy and chemotherapy combined with crizotinib in gingival sarcomatoid squamous cell carcinoma with MET 14 mutation

Background

As a kind of squamous cell carcinoma of head and neck (HNSCC), gingival sarcomatoid squamous cell carcinoma (GSSCC) is a rare biphasic malignant neoplasm. To date, surgical resection was often utilized for gingival squamous cell carcinoma (GSCC), while for patients with advanced gingival carcinoma who cannot tolerate surgery, radiotherapy and chemotherapy can be regarded as a treatment strategy. Many molecular-targeted drugs were investigated and approved for the treatment of malignant diseases, including hematologic diseases and solid tumors. Although targeted therapies such as EGFR inhibitors have shown therapeutic efficacy in HNSCC, there are still some patients who cannot benefit from it. New therapeutic targets and strategies should be further explored.

Case presentation

An 83-year-old woman was referred to our hospital with left lower gingival mass for more than 1 month in June 2021. Pathologic diagnosis is sarcomatoid squamous cell carcinoma. Due to the large tumor at the time of diagnosis and poor quality of life, the patient was intolerant to surgery, so she was given radiotherapy (RT) combined with concurrent chemotherapy (CT) with albumin bound paclitaxel. According to next-generation sequencing (NGS) results (MET exon 14 skipping mutation-positive), she was treated with crizotinib, a tyrosine kinase inhibitor that targets MET. Through the comprehensive treatment, the patient’s condition promptly improved, clinical complete remission (CR) was achieved in 2 months, and 9-month progression-free survival (PFS) was obtained. She finally died from non-cancer-related diseases.

Conclusion

Here we report the treatment of a GSSCC patient with MET mutation, who responded to crizotinib promptly and positively. It provides a new reference for understanding MET abnormalities in GSSCC and offers a new idea for the targeted treatment of gingival carcinoma.

Targeted therapy in lung cancer: Are we closing the gap in years of life lost?

PURPOSE

Patients with non-small cell lung cancer (NSCLC) that harbor driver mutations are associated with a cancer diagnosis at a younger age. While targeted therapies provide deep remissions and durable benefit in a subset of patients, it is unclear whether targeted therapies bridge the gap in years of life lost (YLL) in these younger NSCLC patients with targetable mutations in comparison to generally older NSCLC patients without actionable driver mutations.

MATERIALS AND METHODS

Retrospective cross-sectional study using landmark trials leading to the approval of targeted therapies in NSCLC with actionable mutations. We evaluated all targeted therapies as well as chemotherapy and IO regimens for the treatment of NSCLC through FDA Oncology Announcements and NCCN Guidelines for NSCLC (version 4.2021).

RESULTS

We estimated the YLL for each driver mutation, cumulative median duration of response (DOR) with targeted therapies by mutation type, and percentage of estimated improvement in YLL from NSCLC targeted therapies. The median ages at diagnosis (in years) for patients whose tumors express targetable mutations were: 47.6 (NTRK); 52.0 (ALK); 62.0 (HER2); 57.0 (ROS1); 61.4 (RET); 63.0 (BRAF); 69.0 (EGFR); and 72.0 (MET). For comparison, the median age at diagnosis for patients without driver mutations, regardless of PD-L1 status was 71 years. The median DOR (in years) for patients whose tumors express the same mutations include: 0.9 (NTRK); 3.9 (ALK); 0.6 (HER2); 6.2 (ROS1); 2.2 (RET); 1.5 (BRAF); 3.1 (EGFR); and 2.4 (MET). The median DOR for patients without driver mutations was 1.2 years. The cumulative estimated survival time (years; median age at diagnosis plus the median DOR or OS) for patients whose tumors express targetable mutations were: 48.5 (NTRK); 55.9 (ALK); 62.6 (HER2); 63.2 (ROS1); 63.6 (RET); 64.5 (BRAF); 72.1 (EGFR); and 74.4 (MET). The cumulative estimated survival time for patients without driver mutations, regardless of PD-L1 status, was 72.2 years of age. We calculated the number of years NSCLC is diagnosed earlier in patients with targetable mutations as follows: 23.4 (NTRK), 19 (ALK), 14 (ROS1), 11 (EGFR), 9.6 (RET), 9 (HER2), and 8 (BRAF). The percent difference (%) ameliorated in YLL by mutation type is as follows: 44.3 (ROS1), 28.2 (EGFR), 22.9 (RET), 20.5 (ALK), 18.8 (BRAF), 6.4 (HER2), and 3.7 (NTRK).

CONCLUSION

Although targeted therapies have paved the way for significant progress toward providing a survival benefit to many young patients with advanced NSCLC with actionable mutations, it is evident that these therapies still leave a wide gap in the YLL in these younger patients compared to generally older individuals with advanced NSCLC without targetable mutations.

Characterization of MET Exon 14 Skipping Alterations (in NSCLC) and Identification of Potential Therapeutic Targets Using Whole Transcriptome Sequencing

Introduction

Genomic alterations in the juxtamembrane exon 14 splice sites in NSCLC lead to increased MET stability and oncogenesis. We present the largest cohort study of MET Exon 14 (METex14) using whole transcriptome sequencing.

Methods

A total of 21,582 NSCLC tumor samples underwent complete genomic profiling with next-generation sequencing of DNA (592 Gene Panel, NextSeq, whole exome sequencing, NovaSeq) and RNA (NovaSeq, whole transcriptome sequencing). Clinicopathologic information including programmed death-ligand 1 and tumor mutational burden were collected and RNA expression for mutation subtypes and MET amplification were quantified. Immunogenic signatures and potential pathways of invasion were characterized using single-sample gene set enrichment analysis and mRNA gene signatures.

Results

A total of 533tumors (2.47%) with METex14 were identified. The most common alterations were point mutations (49.5%) at donor splice sites. Most alterations translated to increased MET expression, with MET co-amplification resulting in synergistic increase in expression (q < 0.05). Common coalterations were amplifications of MDM2 (19.0% versus 1.8% wild-type [WT]), HMGA2 (13.2% versus 0.98% WT), and CDK4 (10.0% versus 1.5% WT) (q < 0.05). High programmed death-ligand 1 > 50% (52.5% versus 27.3% WT, q < 0.0001) and lower proportion of high tumor mutational burden (>10 mutations per megabase, 8.3% versus 36.7% WT, p < 0.0001) were associated with METex14, which were also enriched in both immunogenic signatures and immunosuppressive checkpoints. Pathways associated with METex14 included angiogenesis and apical junction pathways (q < 0.05).

Conclusions

METex14 splicing alterations and MET co-amplification translated to higher and synergistic MET expression at the transcriptomic level. High frequencies of MDM2 and CDK4 co-amplifications and association with multiple immunosuppressive checkpoints and angiogenic pathways provide insight into potential actionable targets for combination strategies in METex14 NSCLC.

Comprehensive analysis of MET mutations in NSCLC patients in a real-world setting

Background:

Aberrant mesenchymal–epithelial transition/hepatocyte growth factor (MET/HGF) regulation presented in a wide variety of human cancers. MET exon 14 skipping, copy number gain (CNG), and kinase domain mutations/arrangements were associated with increased MET activity, and considered to be oncogenic drivers of non-small cell lung cancers (NSCLCs).

Methods:

We retrospectively analyzed 564 patients with MET alterations. MET alterations were classified into structural mutations or small mutations. MET CNG, exon 14 skipping, gain of function (GOF) mutations, and kinase domain rearrangement were defined as actionable mutations.

Results:

Six hundred thirty-two MET mutations were identified including 199 CNG, 117 exon 14 skipping, 12 GOF mutations, and 2 actionable fusions. Higher percentage of MET structural alterations (CNG + fusion) were detected in advanced NSCLC patients. Moreover, MET CNG was enriched while exon 14 skipping was rare in epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKI)-treated advanced NSCLC patients. Ten of the 12 MET GOF mutations were also in EGFR-TKI-treated patients. Fifteen (68.1%) of the 22 patients treated with crizotinib or savolitinib had a partial response. Interestingly, one patient had a great response to savolitinib with a novel MET exon 14 skipping mutation identified after failure of immune-checkpoint inhibitor.

Conclusions:

Half of the MET alterations were actionable mutations. MET CNG, exon 14 skipping and GOF mutations had different distribution in different clinical scenario but all defined a molecular subgroup of NSCLCs for which MET inhibition was active.

Targeting molecular alterations in non-small-cell lung cancer: what's next?

In recent years, major advances have been achieved in our understanding of non-small-cell lung cancer (NSCLC) with oncogenic driver alterations and in the specific treatment of these with tyrosine kinase inhibitors. Currently, state-of-the-art management of patients with NSCLC (particularly adenocarcinoma or non-adenocarcinoma but with mild tobacco exposure) consists of the determination of EGFR, ALK, ROS1 and BRAF status, as they have US FDA and EMA approved targeted therapies. The increase in molecular knowledge of NSCLC and the development of drugs against other targets has settled new therapeutic indications. In this review we have incorporated the development around MET, KRAS and NTRK in the diagnosis of NSCLC given the therapeutic potential that they represent, as well as the drugs approved for these indications.

Biomarkers for Systemic Therapy in Metastatic Breast Cancer: ASCO Guideline Update

PURPOSE

To update the ASCO biomarkers to guide systemic therapy for metastatic breast cancer (MBC) guideline.

METHODS

An Expert Panel conducted a systematic review to identify randomized clinical trials and prospective-retrospective studies from January 2015 to January 2022.

RESULTS

The search identified 19 studies informing the evidence base.

RECOMMENDATIONS

Candidates for a regimen with a phosphatidylinositol 3-kinase inhibitor and hormonal therapy should undergo testing for PIK3CA mutations using next-generation sequencing of tumor tissue or circulating tumor DNA (ctDNA) in plasma to determine eligibility for alpelisib plus fulvestrant. If no mutation is found in ctDNA, testing in tumor tissue, if available, should be used. Patients who are candidates for poly (ADP-ribose) polymerase (PARP) inhibitor therapy should undergo testing for germline BRCA1 and BRCA2 pathogenic or likely pathogenic mutations to determine eligibility for a PARP inhibitor. There is insufficient evidence for or against testing for a germline PALB2 pathogenic variant to determine eligibility for PARP inhibitor therapy in the metastatic setting. Candidates for immune checkpoint inhibitor therapy should undergo testing for expression of programmed cell death ligand-1 in the tumor and immune cells to determine eligibility for treatment with pembrolizumab plus chemotherapy. Candidates for an immune checkpoint inhibitor should also undergo testing for deficient mismatch repair/microsatellite instability-high to determine eligibility for dostarlimab-gxly or pembrolizumab, as well as testing for tumor mutational burden. Clinicians may test for NTRK fusions to determine eligibility for TRK inhibitors. There are insufficient data to recommend routine testing of tumors for ESR1 mutations, for homologous recombination deficiency, or for TROP2 expression to guide MBC therapy selection. There are insufficient data to recommend routine use of ctDNA or circulating tumor cells to monitor response to therapy among patients with MBC.Additional information can be found at www.asco.org/breast-cancer-guidelines.

ESMO recommendations on the use of circulating tumour DNA assays for patients with cancer: a report from the ESMO Precision Medicine Working Group

Circulating tumour DNA (ctDNA) assays conducted on plasma are rapidly developing a strong evidence base for use in patients with cancer. The European Society for Medical Oncology convened an expert working group to review the analytical and clinical validity and utility of ctDNA assays. For patients with advanced cancer, validated and adequately sensitive ctDNA assays have utility in identifying actionable mutations to direct targeted therapy, and may be used in routine clinical practice, provided the limitations of the assays are taken into account. Tissue based testing remains the preferred test for many cancer patients, due to limitations of ctDNA assays detecting fusion events and copy number changes, although ctDNA assays may be routinely used when faster results will be clinically important, or when tissue biopsies are not possible or inappropriate. Reflex tumour testing should be considered following a non-informative ctDNA result, due to false negative results with ctDNA testing. In patients treated for early-stage cancers, detection of molecular residual disease (MRD) or molecular relapse (MR), has high evidence of clinical validity in anticipating future relapse in many cancers. MRD/MR detection cannot be recommended in routine clinical practice, as currently there is no evidence for clinical utility in directing treatment. Additional potential applications of ctDNA assays, under research development and not recommended for routine practice, include identifying patients not responding to therapy with early dynamic changes in ctDNA levels, monitoring therapy for the development of resistance mutations prior to clinical progression, and in screening asymptomatic people for cancer. Recommendation for reporting of results, future development of ctDNA assays, and future clinical research are made.

Novel targeted therapies for advanced non-small lung cancer

Non-small cell lung cancer (NSCLC) is the most common type of lung cancer accounting for almost 80%-85% of all lung cancer cases. Unfortunately, more than half of the patients will be diagnosed with advanced disease at the time of presentation, which makes their disease incurable. Historically, the 5 year overall survival for advanced NSCLC was 5%. However, there has been a significant increase in our understanding of the genetic basis of NSCLC, which has led to development of both immunotherapy and targeted therapy agents. This has improved the 5 year overall survival to become within the range of 15%-50% depending on certain mutations and biomarkers. Over the last decade the United States Food and Drug Administration (FDA) has approved almost 20 new targeted therapies and clinical trials are still undergoing to evaluate more novel agents. In this review, we will present recent updates on novel targeted therapies.

MET∆14 promotes a ligand-dependent, AKT-driven invasive growth

MET is an oncogene encoding the tyrosine kinase receptor for hepatocyte growth factor (HGF). Upon ligand binding, MET activates multiple signal transducers, including PI3K/AKT, STAT3, and MAPK. When mutated or amplified, MET becomes a "driver" for the onset and progression of cancer. The most frequent mutations in the MET gene affect the splicing sites of exon 14, leading to the deletion of the receptor's juxtamembrane domain (MET∆14). It is currently believed that, as in gene amplification, MET∆14 kinase is constitutively active. Our analysis of MET in carcinoma cell lines showed that MET∆14 strictly depends on HGF for kinase activation. Compared with wt MET, ∆14 is sensitive to lower HGF concentrations, with more sustained kinase response. Using three different models, we have demonstrated that MET∆14 activation leads to robust phosphorylation of AKT, leading to a distinctive transcriptomic signature. Functional studies revealed that ∆14 activation is predominantly responsible for enhanced protection from apoptosis and cellular migration. Thus, the unique HGF-dependent ∆14 oncogenic activity suggests consideration of HGF in the tumour microenvironment to select patients for clinical trials.

Correlation of Immunological and Molecular Profiles with Response to Crizotinib in Alveolar Soft Part Sarcoma: An Exploratory Study Related to the EORTC 90101 "CREATE" Trial

Alveolar soft part sarcoma (ASPS) is a rare subtype of soft tissue sarcoma characterized by an unbalanced translocation, resulting in ASPSCR1-TFE3 fusion that transcriptionally upregulates MET expression. The European Organization for Research and Treatment of Cancer (EORTC) 90101 “CREATE” phase II trial evaluated the MET inhibitor crizotinib in ASPS patients, achieving only limited antitumor activity. We performed a comprehensive molecular analysis of ASPS tissue samples collected in this trial to identify potential biomarkers correlating with treatment outcome. A tissue microarray containing 47 ASPS cases was used for the characterization of the tumor microenvironment using multiplex immunofluorescence. DNA isolated from 34 available tumor samples was analyzed to detect recurrent gene copy number alterations (CNAs) and mutations by low-coverage whole-genome sequencing and whole-exome sequencing. Pathway enrichment analysis was used to identify diseased-associated pathways in ASPS sarcomagenesis. Kaplan–Meier estimates, Cox regression, and the Fisher’s exact test were used to correlate histopathological and molecular findings with clinical data related to crizotinib treatment, aiming to identify potential factors associated with patient outcome. Tumor microenvironment characterization showed the presence of PD-L1 and CTLA-4 in 10 and 2 tumors, respectively, and the absence of PD-1 in all specimens. Apart from CD68, other immunological markers were rarely expressed, suggesting a low level of tumor-infiltrating lymphocytes in ASPS. By CNA analysis, we detected a number of broad and focal alterations. The most common alteration was the loss of chromosomal region 1p36.32 in 44% of cases. The loss of chromosomal regions 1p36.32, 1p33, 1p22.2, and 8p was associated with shorter progression-free survival. Using whole-exome sequencing, 13 cancer-associated genes were found to be mutated in at least three cases. Pathway enrichment analysis identified genetic alterations in NOTCH signaling, chromatin organization, and SUMOylation pathways. NOTCH4 intracellular domain dysregulation was associated with poor outcome, while inactivation of the beta-catenin/TCF complex correlated with improved outcome in patients receiving crizotinib. ASPS is characterized by molecular heterogeneity. We identify genetic aberrations potentially predictive of treatment outcome during crizotinib therapy and provide additional insights into the biology of ASPS, paving the way to improve treatment approaches for this extremely rare malignancy.

FFPE-Based NGS Approaches into Clinical Practice: The Limits of Glory from a Pathologist Viewpoint

The introduction of next-generation sequencing (NGS) in the molecular diagnostic armamentarium is deeply changing pathology practice and laboratory frameworks. NGS allows for the comprehensive molecular characterization of neoplasms, in order to provide the best treatment to oncologic patients. On the other hand, NGS raises technical issues and poses several challenges in terms of education, infrastructures and costs. The aim of this review is to give an overview of the main NGS sequencing platforms that can be used in current molecular diagnostics and gain insights into the clinical applications of NGS in precision oncology. Hence, we also focus on the preanalytical, analytical and interpretative issues raised by the incorporation of NGS in routine pathology diagnostics.