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Background: Capmatinib is a selective MET inhibitor with demonstrated efficacy in a phase II study of non-small cell lung cancer (NSCLC) patients harboring METex14 mutations. However, the real-world outcomes of capmatinib are largely unknown. From June 2019, the French Early Access Program (EAP) provided capmatinib to METex14 NSCLC patients who were ineligible for or for whom first-line standard therapies had failed., Methods: IFCT-2104 CAPMATU was a multicenter study that included all METex14 NSCLC patients who received capmatinib as part of the EAP until August 2021. The primary endpoints were time to treatment failure (TTF), progression-free survival (PFS), overall survival (OS) and objective response rate (ORR)., Results: A total of 146 patients were included. The median age was 74.9 years, 56.6 % were never-smokers, and 32.4 % had brain metastases. The median TTF, median PFS and median OS from capmatinib initiation were 5.1 months (95 % CI 4.2-6.0), 4.8 months (95 % CI 4.0-6.0) and 10.4 months (95 % CI 8.3-13.2), respectively. Evaluation of the best response to capmatinib was available for 134 patients and resulted in an ORR of 55.3 % (95 % CI 46.8 %-63.6 %). The median PFS was 7.7 months for treatment-naïve patients and 6.0 and 4.1 months for patients who had received one or 2 + prior lines of treatment, respectively. For patients with brain metastases, the median PFS was 3.0 months. Capmatinib had a known and manageable safety profile, with grade 3 to 4 adverse events, mostly peripheral edema (8.2 %), occurring in 17.8 % of patients., Conclusion: In this large real-world study of METex14 NSCLC patients, the efficacy of capmatinib was confirmed, with a manageable safety profile, even in patients with brain metastases and in those who received several lines of treatment. This study reinforces the key role of capmatinib for these patients., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: M. Ferreira: Financial Interests, Personal, Other, Travel, Accommodations, Expenses: AstraZeneca, BMS. A. Swalduz: Financial Interests, Personal, Other, honoraria: AstraZeneca, Janssen, Roche, Amgen, BMS; Financial Interests, Personal, Advisory Role: AstraZeneca, Janssen, Roche, Amgen, BMS, Pfizer, Lilly. P. du Rusquec: Financial Interests, Personal, Other, Travel, Accommodations: Roche, Pfizer, Sandoz, Daiichi Sankyo, Merck, Novartis, Lilly, Amgen, Eisai, BMS, Takeda, AstraZeneca, Janssen, Sanofi. Advisory Role: Sanofi, Takeda. A.C. Toffart: Financial Interests, Personal, Advisory Role: AstraZeneca, MSD, BMS, Roche, Amgen, Takeda, Jannsen. J. Raimbourg: Financial Interests, Personal, Other, Travel, Accommodations, Expenses: BMS. V. Gounant: Financial Interests, Personal, Advisory Role: BMS, AstraZeneca, Takeda; Financial Interests, Personal, Other, Travel, Accommodations, Expenses: Sanofi, Pfizer. S. Couraud: Financial Interests, Personal, Other, honoraria: Amgen, AstraZeneca, BMS, MSD, Roche, Sanofi, Fabentech, Boehringer Ingelheim, Takeda; Financial Interests, Institutional, Research Grant: Amgen, AstraZeneca, BMS, MSD, Roche, Sanofi, Chugai, Novartis, Pfizer, Sysmex, Cellgene, Takeda, Janssen; Financial Interests, Personal, Other, Travel, Accommodations, Expenses: AstraZeneca, Roche, Takeda. M. Wislez: Financial Interests, Personal, Advisory Role: AstraZeneca, MSD, Amgen, BMS, Roche; Financial Interests, Personal, Speaker’s Bureau: AstraZeneca, MSD, Amgen, BMS, Roche; Financial Interests, Institutional, Funding, research funding: AstraZeneca; Financial Interests, Personal, Other, Travel, Accommodations, Expenses: AstraZeneca, MSD, Amgen, BMS, Roche. C. Descarpentries reports personal fees and nonfinancial support from AstraZeneca, personal fees and nonfinancial support from Novartis Pharma SAS, nonfinancial support from Roche SAS, nonfinancial support from Boehringer Ingelheim france, nonfinancial support from Pfizer, outside the submitted work; G. Herbreteau reports personal fees and nonfinancial support from Pierre Fabre Oncology. V. Westeel: Financial Interests, Personal, Other, Honoraria: AstraZeneca, BMS, Amgen, Roche; Financial Interests, Personal, Advisory Role: MSD, Takeda; Financial Interests, Personal, Speaker’s Bureau: BMS, AstraZeneca, Roche, MSD, Pfizer, Amgen; Financial Interests, Personal, Other, Travel, Accommodations, Expenses: BMS, AstraZeneca, Sanofi. A. B. Cortot: Financial Interests, Personal, Other, Consulting fees: Roche Novartis; Financial Interests, Personal, Other, Honoraria: Novartis Pfizer Takeda Roche; Financial Interests, Personal, Advisory Board: Roche Novartis Pfizer Takeda. All other authors have declared no conflicts of interest., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Introduction: MET exon 14 (METex14) skipping is a rare oncogenic driver in non-small-cell lung cancer (NSCLC) for which targeted therapy with MET tyrosine kinase inhibitors (TKIs) was recently approved. Given the heterogeneity in published data of METex14 skipping NSCLC, we conducted a systematic literature review to evaluate its frequency, patient characteristics, and outcomes., Methods: On June 13, 2022 we conducted a systematic literature review of publications and conference abstracts reporting frequency, patient characteristics, or outcomes of patients with METex14 skipping NSCLC., Results: We included 139 studies reporting frequency or patient characteristics (350,997 patients), and 39 studies reporting clinical outcomes (3989 patients). Median METex14 skipping frequency was 2.0% in unselected patients with NSCLC, with minimal geographic variation. Median frequency was 2.4% in adenocarcinoma or nonsquamous subgroups, 12.0% in sarcomatoid, and 1.3% in squamous histology. Patients with METex14 skipping NSCLC were more likely to be elderly, have adenocarcinoma histology; there was no marked sex or smoking status distribution. In first line of treatment, median objective response rate ranged from 50.7% to 68.8% with targeted therapies (both values correspond to MET TKIs), was 33.3% with immunotherapy, and ranged from 23.1% to 27.0% with chemotherapy., Conclusions: Patients with METex14 skipping are more likely to have certain characteristics, but no patient subgroup can be ruled out; thus, it is crucial to test all patients with NSCLC to identify suitable candidates for MET inhibitor therapy. MET TKIs appeared to result in higher efficacy outcomes, although no direct comparison with chemotherapy or immunotherapy regimens was found., Competing Interests: Disclosure Julien Mazieres has received grants or contracts from AstraZeneca, Roche and Pierre Fabre and honoraria from the healthcare business of Merck KGaA, Darmstadt, Germany, AstraZeneca, BMS, Merck & Co., Roche, Novartis, Daiichi and Pfizer. Alexis Cortot has received grants or contracts from the healthcare business of Merck KGaA, Darmstadt, Germany and Novartis; consulting fees from AstraZeneca, BMS, Novartis, Pfizer, Takeda and Roche; honoraria from AstraZeneca, BMS, Merck & Co., Novartis, Pfizer, Takeda and Roche and meeting/travel support from AstraZeneca, Merck & Co., Novartis, Pfizer, Takeda and Roche. Rhiannon I. Campden, Nora Zhiyuan Chen, and Bart Heeg are employed by Ingress Health, a Cytel company, contracted by the healthcare business of Merck KGaA, Darmstadt, Germany to support with this study. Boris Pfeiffer and Helene Vioix are employees of the healthcare business of Merck KGaA, Darmstadt, Germany., (Copyright © 2023. Published by Elsevier Inc.)

MET is a receptor tyrosine kinase that is activated in many cancers through various mechanisms. MET exon 14 (Ex14) skipping occurs in 3% of nonsmall cell lung tumors. However, the contribution of the regulatory sites lost upon this skipping, which include a phosphorylated serine (S985) and a binding site for the E3 ubiquitin ligase CBL (Y1003), remains elusive. Sequencing of 2808 lung tumors revealed 71 mutations leading to MET exon 14 skipping and three mutations affecting Y1003 or S985. In addition, MET exon 14 skipping and MET Y1003F induced similar transcriptional programs, increased the activation of downstream signaling pathways, and increased cell mobility. Therefore, the MET Y1003F mutation is able to fully recapitulate responses induced by MET exon 14 skipping, suggesting that loss of the CBL binding site is the main contributor of cell transformation induced by MET Ex14 mutations., (© 2023 Federation of European Biochemical Societies.)

Although targeted therapies have increased the life expectancy of patients with druggable molecular alterations directly involved in tumor development, the efficacy of these therapies is limited by acquired resistances leading to treatment failure. Most targeted therapies, including ones exploiting therapeutic antibodies and kinase inhibitors, are directed against receptor tyrosine kinases (RTKs) or major signaling hubs. Resistances to these therapies arise when inhibition of these targets is bypassed through activation of alternative signaling pathways. In recent years, activation of the receptor tyrosine kinase MET has been shown to promote resistance to various targeted therapies. This casts MET as important actor in resistance. In this review, we describe how the MET receptor triggers resistance to targeted therapies against RTKs such as EGFR, VEGFR, and HER2 and against signaling hubs such as BRAF. We also describe how MET can be its own resistance factor, as illustrated by on-target resistance of lung tumors harboring activating mutations causing MET exon 14 skipping. Interestingly, investigation of all these situations reveals functional physiological relationships between MET and the target of the therapy to which the cancer becomes resistant, suggesting that resistance stems from preexisting mechanisms. Identification of MET as a resistance factor opens the way to co-treatment strategies that are being tested in current clinical trials.

Background: A splice-site mutation that results in a loss of transcription of exon 14 in the oncogenic driver MET occurs in 3 to 4% of patients with non-small-cell lung cancer (NSCLC). We evaluated the efficacy and safety of tepotinib, a highly selective MET inhibitor, in this patient population., Methods: In this open-label, phase 2 study, we administered tepotinib (at a dose of 500 mg) once daily in patients with advanced or metastatic NSCLC with a confirmed MET exon 14 skipping mutation. The primary end point was the objective response by independent review among patients who had undergone at least 9 months of follow-up. The response was also analyzed according to whether the presence of a MET exon 14 skipping mutation was detected on liquid biopsy or tissue biopsy., Results: As of January 1, 2020, a total of 152 patients had received tepotinib, and 99 patients had been followed for at least 9 months. The response rate by independent review was 46% (95% confidence interval [CI], 36 to 57), with a median duration of response of 11.1 months (95% CI, 7.2 to could not be estimated) in the combined-biopsy group. The response rate was 48% (95% CI, 36 to 61) among 66 patients in the liquid-biopsy group and 50% (95% CI, 37 to 63) among 60 patients in the tissue-biopsy group; 27 patients had positive results according to both methods. The investigator-assessed response rate was 56% (95% CI, 45 to 66) and was similar regardless of the previous therapy received for advanced or metastatic disease. Adverse events of grade 3 or higher that were considered by investigators to be related to tepotinib therapy were reported in 28% of the patients, including peripheral edema in 7%. Adverse events led to permanent discontinuation of tepotinib in 11% of the patients. A molecular response, as measured in circulating free DNA, was observed in 67% of the patients with matched liquid-biopsy samples at baseline and during treatment., Conclusions: Among patients with advanced NSCLC with a confirmed MET exon 14 skipping mutation, the use of tepotinib was associated with a partial response in approximately half the patients. Peripheral edema was the main toxic effect of grade 3 or higher. (Funded by Merck [Darmstadt, Germany]; VISION ClinicalTrials.gov number, NCT02864992.)., (Copyright © 2020 Massachusetts Medical Society.)

Introduction: MNNG HOS transforming gene (MET) abnormalities such as amplification and exon 14 mutations may be responsive to targeted therapies. They are prevalent in lung sarcomatoid carcinomas (LSCs) and must be diagnosed as efficiently as possible. Hypothetically, c-MET overexpression by immunohistochemistry (IHC) may prove effective as a screening test for MET abnormalities., Methods: Tissue samples were obtained from consecutive patients with a resected LSC in four oncologic centers. IHC was performed using the SP44 antibody (Ventana, Tucson, Arizona) and evaluated using the MetMab score and H-score. Fluorescence in situ hybridization was applied with the dual color probe set from Zytovision (Clinisciences, Nanterre, France). True MET amplification was diagnosed when MET gene copy number was 5 or greater and the ratio between MET gene copy number and chromosome 7 number was greater than 2. All MET exon 14 alterations including those affecting splice sites occurring within splice donor and acceptor sites were detected in the routine molecular testing on genetic platforms., Results: A total of 81 LSCs were included. Fourteen (17%) exhibited positive IHC using the MetMab score and 15 (18.5%) using the H-score. MET amplification was detected in six tumors (8.5%) and MET exon 14 mutation in five (6%). A weak positive correlation between IHC and fluorescence in situ hybridization was found (r = 0.27, p = 0.0001). IHC sensitivity for MET amplification was 50%, with a specificity of 83%, positive predictive value of 21.4%, and negative predictive value of 94.7%. IHC sensitivity for MET exon 14 mutations was 20%, with a specificity of 83%, positive predictive value of 7%, and negative predictive value of 94%., Conclusion: IHC is not a relevant screening tool for MET abnormalities in LSC., (Copyright © 2018 International Association for the Study of Lung Cancer. Published by Elsevier Inc. All rights reserved.)

Introduction: Genomic alterations affecting splice sites of MNNG HOS transforming gene (MET) exon 14 were recently identified in NSCLC patients. Objective responses to MET tyrosine kinase inhibitors have been reported in these patients. Thus, detection of MET exon 14 splice site mutations represents a major challenge. So far, most of these alterations were found by full-exome sequencing or large capture-based next-generation sequencing (NGS) panels, which are not suitable for routine diagnosis., Methods: Aiming to provide a molecular testing method applicable in routine practice, we first developed a fragment-length analysis for detecting deletions in introns flanking MET exon 14. Second, we designed an optimized targeted NGS panel called CLAPv1, covering the MET exon 14 and flanking regions in addition to the main molecular targets usually covered in genomic testing. In patients with MET exon 14 mutations, MET gene amplification, gene copy number and MET receptor expression were also determined., Results: Among 1514 formalin-fixed paraffin-embedded NSCLC samples, nonoptimized NGS allowed detection of MET exon 14 mutations in only 0.3% of the patients, and fragment length analysis detected deletions in 1.1% of the patients. Combined, the optimized CLAPv1 panel and fragment-length analysis implemented for routine molecular testing revealed MET exon 14 alterations in 2.2% of 365 additional NSCLC patients. MET gene amplification or high gene copy number was observed in 6 of 30 patients (20%) harboring MET exon 14 mutations., Conclusions: These results show that optimized targeted NGS and fragment-length analysis improve detection of MET alterations in routine practice., (Copyright © 2018 International Association for the Study of Lung Cancer. Published by Elsevier Inc. All rights reserved.)

Background: Five to 20% of metastatic EGFR-mutated non-small cell lung cancers (NSCLC) develop acquired resistance to EGFR tyrosine kinase inhibitors (EGFR-TKI) through MET amplification. The effects of MET amplification on tumor and patient phenotype remain unknown., Methods: We investigated,in vitro and in vivo, the impact of MET amplification on the biological properties of the HCC827 cell line, derived from an EGFR-mutated NSCLC. We further evaluated the time to new metastases after EGFR-TKI progression in EGFR-mutated NSCLC, exhibiting MET amplification or high MET overexpression., Results: MET amplification significantly enhanced proliferation, anchorage independent growth, anoikis resistance, migration, and induced an epithelial to mesenchymal transition. In vivo, MET amplification significantly increased the tumor growth and metastatic spread. Treatment with a MET-TKI reversed this aggressive phenotype. We found that EGFR-mutated NSCLC patients exhibiting MET amplification on a re-biopsy, performed after EGFR-TKI progression, displayed a shorter time to new metastases after EGFR-TKI progression than patients with high MET overexpression but no MET amplification., Conclusion: MET amplification increases metastatic spread even in the context of an already pre-existing strong driver mutation such as EGFR mutation. These results prompt development of therapeutic strategies aiming at preventing emergence of MET amplification., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Targeted therapies against receptor tyrosine kinases (RTKs) are currently used with success on a small proportion of patients displaying clear oncogene activation. Lung cancers with a mutated EGFR provide a good illustration. The efficacy of targeted treatments relies on oncogene addiction, a situation in which the growth or survival of the cancer cells depends on a single deregulated oncogene. MET, a member of the RTK family, is a promising target because it displays many deregulations in a broad panel of cancers. Although clinical trials having evaluated MET inhibitors in large populations have yielded disappointing results, many recent case reports suggest that MET inhibition may be effective in a subset of patients with unambiguous MET activation and thus, most probably, oncogene addiction. Interestingly, preclinical studies have revealed a particularity of MET addiction: it can arise through several mechanisms, and the mechanism involved can differ according to the cancer type. The present review describes the different mechanisms of MET addiction and their consequences for diagnosis and therapeutic strategies. Although in each cancer type MET addiction affects a restricted number of patients, pooling of these patients across all cancer types yields a targetable population liable to benefit from addiction-targeting therapies.

Inhibitors of the receptor tyrosine kinase (RTK) MET have been ineffective at treating cancer, possibly because of lack of knowledge that would allow selection of tumors likely to respond to this treatment. In contrast, specific epidermal growth factor receptor (EGFR) inhibitors have been used successfully against lung tumors displaying activating mutations in the kinase domain of EGFR. Recent publications describe a set of mutations causing MET exon 14 skipping, and importantly, several case reports describe objective responses to MET-targeting tyrosine kinase inhibitors in patients with such mutations. These observations suggest a novel therapeutic strategy for fighting cancer, especially in the lung. Exon 14 encodes the MET juxtamembrane domain targeted by mechanisms that negatively regulate receptor stability and activity. In this review, we describe the molecular mechanisms leading first to exon 14 skipping and then to activation of the MET receptor and how this process differs from that triggered by classical RTK-activating mutations in the kinase domain. We detail the clinical characteristics of patients carrying these mutations and the sensitivity of their tumors to MET inhibitors. Lastly, we discuss future challenges related to MET mutations in cancers, including patient screening and anticipating resistance to MET inhibitors., (© The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

The involvement of the HGF/MET pathway in acquisition of an invasive phenotype in non-small cell lung carcinomas (NSCLCs) suggests that MET inhibitors might prove effective against these cancers, but clinical trials have yielded conflicting results. The aim of our study was to evaluate how intratumoral heterogeneity (ITH) of MET staining affects the determination of MET status for therapeutic purposes. We analyzed 64 NSCLC samples, including 33 adenocarcinomas (ADCs) and 31 squamous cell carcinomas (SCCs). We used immunohistochemistry to detect MET and phospho-MET on whole slides and determined the MET SP44 immunoscore and the H-score. A high METMab score (2+/3+) was observed in 34% of NSCLCs and was more prevalent in ADCs (52%) than in SCCs (16%). We found ITH in 73% of ADCs and 77% of SCCs, with higher levels of MET and phospho-MET at the invasion front (in 52% of ADCs and 22% of SCCs) and in tumor cells spreading through air spaces in ADCs. Within-sample ITH was high in 40% of the ADCs and 29% of the SCCs. When different samples from the same tumor were compared, discordant assessments (high MET vs. low MET) were made for 12% of the ADCs and 10% of the SCCs. C-MET and phospho-MET overexpression occurred preferentially in ADCs and in areas involved in tumor progression, in support of the view that MET activation plays a role in the development of an invasive phenotype in NSCLC. To use MET status adequately as a biomarker, one must take the resulting high level of ITH into account.

The receptor tyrosine kinase MET and its ligand, the hepatocyte growth factor, are essential to embryonic development, whereas deregulation of MET signaling is associated with tumorigenesis leading to various cancers, including lung carcinoma. Mutations in the MET kinase domain lead to constitutive kinase activity and are associated with tumorigenesis. In lung cancer, however, some mutations are found in the juxtamembrane domain, and their functional consequences are unknown. Because the juxtamembrane domain of MET is targeted by several proteolytic cleavages, involved in its degradation during cell death or under steady-state conditions, we evaluated the influence of these mutations on the MET proteolytic cleavages. In stably transfected epithelial cells expressing MET, the juxtamembrane mutations R970C, P991S, and T992I were found not to modify the known caspase or presenilin-dependent regulated intramembrane proteolysis. Yet when overexpressed, the R970C variant caused generation of an as yet undescribed 45-kDa fragment (p45 MET). This fragment was found in the confluent lung cancer cell line NCI-H1437 carrying the R970C mutation and at a lesser extent in cell lines expressing WT MET, suggesting that R970C mutation favors this cleavage. Generation of p45 MET required the activity of the calpain proteases, confirming the involvement of proteolysis. Ectopic expression of reconstituted p45 MET in epithelial cell lines favored cell scattering and invasion indicating active role of this fragment in HGF/SF induced responses. Hence, although the juxtamembrane mutations of MET do not affect its known proteolytic cleavages, the R970C MET variant favors calpain dependent proteolytic cleavage in lung cancer cells.

Objectives: The receptor tyrosine kinase MET is essential to embryonic development and organ regeneration. Its deregulation is associated with tumorigenesis. While MET gene amplification and mutations leading to MET self-activation concern only a few patients, a high MET level has been found in about half of the non-small cell lung cancers (NSCLCs) tested. How this affects MET activation in tumors is unclear. Also uncertain is the prognostic value, in cancer, of a phenomenon well described in cell models: MET shedding, i.e. its cleavage by membrane proteases leading to release of a soluble fragment into the medium., Materials and Methods: A prospective cohort of 39 NSCLC patients was constituted at diagnosis or soon after. Normal tissues, tumor tissues, and blood samples were obtained. This allowed, for the same patient, synchronous determination of (i) the MET level in the tumor, (ii) receptor phosphorylation, and (iii) the concentration of soluble MET fragment (sMET) in the serum., Results: After confirming the adequacy of an ELISA for measuring the serum level of sMET, we found no correlation between this level and the concentration of MET in tumors, as evaluated by immunohistochemistry and western blotting. Nevertheless, all but one tumor displaying a high MET level also displayed receptor phosphorylation, restricted to a small number of tumor cells., Conclusion: Our results thus demonstrate that the serum level of sMET is not indicative of the amount of MET present in the tumor cells and cannot be used as a biomarker for therapeutic purposes. However, MET scoring of tumor biopsies could be a first step prior to determination of MET receptor activation in high-MET tumors., (Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.)

Various solid tumors including lung or gastric carcinomas display aberrant activation of the Met receptor which correlates with aggressive phenotypes and poor prognosis. Although downstream signaling of Met is well described, its integration at the transcriptional level is poorly understood. We demonstrate here that in cancer cells harboring met gene amplification, inhibition of Met activity with tyrosine kinase inhibitors or specific siRNA drastically decreased expression of ETV1, ETV4 and ETV5, three transcription factors constituting the PEA3 subgroup of the ETS family, while expression of the other members of the family were less or not affected. Similar link between Met activity and PEA3 factors expression was found in lung cancer cells displaying resistance to EGFR targeted therapy involving met gene amplification. Using silencing experiments, we demonstrate that the PEA3 factors are required for efficient migration and invasion mediated by Met, while other biological responses such as proliferation or unanchored growth remain unaffected. PEA3 overexpression or silencing revealed that they participated in the regulation of the MMP2 target gene involved in extracellular matrix remodeling. Our results demonstrated that PEA3-subgroup transcription factors are key players of the Met signaling integration involved in regulation of migration and invasiveness., (Copyright © 2015 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.)