MET Tyrosine Kinase Inhibitors Research Articles

In vitro effectiveness of CB469, a MET tyrosine kinase inhibitor in MET-activated cancer cells

Gene alterations in receptor tyrosine kinases can result in oncogenic driver mutation in non-small cell lung cancer (NSCLC) including in genes like EGFR, ALK and MET. MET amplifications and MET exon14 skipping are the primary genetic changes in MET-altered cancers. Acquired MET mutations mediate resistance to clinical MET-targeted therapy in NSCLC. MET kinase domain secondary mutations (D1228X, Y1230X) confer resistance to type I MET tyrosine kinase inhibitors (TKIs) in METexon14-altered or MET amplified NSCLC. Here, we investigated the preclinical activity of a novel MET inhibitor, CB469, with cell growth, signaling pathway and colony formation. We confirmed that CB469 inhibited the activity of MET wild and secondary mutant kinases, D1228N and Y1230H, as a type II inhibitor. CB469 also inhibited cell growth and cell signaling proteins in MET-activated or MET exon14 skipping-mutated cancer cell lines and NIH/3T3 cells expressing an engineered MET mutant. CB469 exhibited the inhibitory efficacy comparable with that of capmatinib in migration of EBC-1(METwt) and Hs746T(METΔex14) cells. Finally, CB469 showed selective and potent inhibition in MET-activated cancer cells among MET TKIs leading to enhanced selectivity for MET-mutant versus wild type MET with inhibition of cell growth in NIH/3T3 cells expressing an engineered MET mutant variant.

Functional interaction between receptor tyrosine kinase MET and ETS transcription factors promotes prostate cancer progression.

Prostate cancer, the most common malignancy in men, has a relatively favourable prognosis. However, when it spreads to the bone, the survival rate drops dramatically. The development of bone metastases leaves patients with aggressive prostate cancer, the leading cause of death in men. Moreover, bone metastases are incurable and very painful. Hepatocyte growth factor receptor (MET) and fusion of genes encoding E26 transformation-specific (ETS) transcription factors are both involved in the progression of the disease. ETS gene fusions, in particular, have the ability to induce the migratory and invasive properties of prostate cancer cells, whereas MET receptor, through its signalling cascades, is able to activate transcription factor expression. MET signalling and ETS gene fusions are intimately linked to high-grade prostate cancer. However, the collaboration of these factors in prostate cancer progression has not yet been investigated. Here, we show, using cell models of advanced prostate cancer, that ETS translocation variant 1 (ETV1) and transcriptional regulator ERG (ERG) transcription factors (members of the ETS family) promote tumour properties, and that activation of MET signalling enhances these effects. By using a specific MET tyrosine kinase inhibitor in a humanised hepatocyte growth factor (HGF) mouse model, we also establish that MET activity is required for ETV1/ERG-mediated tumour growth. Finally, by performing a comparative transcriptomic analysis, we identify target genes that could play a relevant role in these cellular processes. Thus, our results demonstrate for the first time in prostate cancer models a functional interaction between ETS transcription factors (ETV1 and ERG) and MET signalling that confers more aggressive properties and highlight a molecular signature characteristic of this combined action.

The Treatment of a New Entity in Advanced Non-small Cell Lung Cancer: MET Exon 14 Skipping Mutation.

MET (MET Proto-Oncogene, Receptor Tyrosine Kinase) exon 14 skipping mutation represents one of the most common MET alterations, accounting for approximately 1-3% of all mutations in advanced lung adenocarcinomas. While until 2020 no specific treatment was available for this subset of patients, as of today, three MET Tyrosine Kinase Inhibitors (TKIs) are currently approved in this setting, namely capmatinib, tepotinib and savolitinib. This article aims to provide an extensive overview of the current therapeutic standard of care for exon 14 skipped advanced Non-small Cell Lung Cancer (NSCLC) patients, alongside with mentions of the main future challenges and opportunities. FDA-approved MET-TKIs currently represent the best option for treating exon 14 skipped advanced NSCLC patients, thanks to their excellent efficacy profile, alongside their manageable safety and tolerability. However, we currently lack specific agents to treat patients progressing on capmatinib or tepotinib, due to a limited understanding of the mechanisms underlying both on- and off-target resistance. In this respect, on-target mutations presently constitute the most explored ones from a mechanistic point of view, and type II MET-TKIs are currently under investigation as the most promising agents capable of overcoming the acquired resistance.

MET exon 14 skipping in NSCLC: An unMET Indian need.

e13537 Background: The approval of capmatinib and tepotinib, selective MET tyrosine kinase inhibitors (TKI), has further shifted the therapeutic paradigm of advanced NSCLC. MET exon 14 skipping (MET ex14) alteration is a complex mechanism, reported in ~3-4% cases of NSCLC. Controlled trials have reported remarkable outcomes of selective MET TKIs, however real world outcomes from this part of the world are currently lacking. Methods: This is a non-interventional study reporting real world outcomes of NSCLC with MET ex14 from two apex cancer centers of India. 49 eligible patients were recovered from the electronic medical record archives. All cases with MET ex14 were included irrespective of clinicopathologic characteristics and therapy offered. Statistical analysis was performed using R studio. Results: Clinical characteristics are shown (Table). Treatment patterns were heterogeneous across therapy lines and included chemotherapy, MET TKIs and immune checkpoint inhibitors. 42/49 patients opted for treatment; rest dropped out owing to economic restraints. 1st line TKI was offered to 14 patients, and chemotherapy to 28 patients. 1st line PFS of TKI treated was 11.9 months (95%CI:5.8-17.8) vs. 5.9months (95%CI: 3.9-16.8) (p<0.002*) for the chemotherapy treated cases (HR for TKI: 0.3295 (95%CI: 0.1630 to 0.6663). Presence of TP53 co-mutation and male gender and were factors affecting 1st line PFS (p<0.06) on multivariate analysis. 2nd line treatment was opted by 13/14 patients in TKI treated group of which 5 received sequential TKI, and 8 received chemotherapy and 22/28 in chemotherapy treated group (TKI: 14, chemotherapy: 8). PFS for 2nd line TKI was 7.7 months (95%CI: 2.8-14.8) vs 4.6 months (95%CI:2.1-9.8) for chemotherapy {HR for TKI: 0.3641 (95%CI: 0.1378 to 0.9616)} (p<0.04*). The dropout rate from 1st to 2nd line was 36% and 44% in subsequent line. 28 (57%) received MET TKI at any given point in disease course. Median OS for patients treated with 1st line TKI was not reached at study end (95%CI: 9.2-NR) and was 20.7 months (95%CI:18.1-36.1) for chemotherapy (p=0.3). One year and 2 year survival rates for 1st line TKI and Chemotherapy were 86%vs 73% and 47% vs 45%, respectively. Conclusions: This is the largest cohort from India reporting real world uptake of TKI therapy in MET ex14 altered NSCLC. There is a blaring disparity with respect to accessibility of drugs, as well as prevailing socioeconomic restraints. This study clearly depicts an unmet need for more global clinical trials for rare genomic alterations as well as patient access programs in this part of the world. [Table: see text]

PAI-1 mediates acquired resistance to MET-targeted therapy in non-small cell lung cancer.

Mechanisms underlying primary and acquired resistance to MET tyrosine kinase inhibitors (TKIs) in managing non-small cell lung cancer remain unclear. In this study, we investigated the possible mechanisms acquired for crizotinib in MET-amplified lung carcinoma cell lines. Two MET-amplified lung cancer cell lines, EBC-1 and H1993, were established for acquired resistance to MET-TKI crizotinib and were functionally elucidated. Genomic and transcriptomic data were used to assess the factors contributing to the resistance mechanism, and the alterations hypothesized to confer resistance were validated. Multiple mechanisms underlie acquired resistance to crizotinib in MET-amplified lung cancer cell lines. In EBC-1-derived resistant cells, the overexpression of SERPINE1, the gene encoding plasminogen activator inhibitor-1 (PAI-1), mediated the drug resistance mechanism. Crizotinib resistance was addressed by combination therapy with a PAI-1 inhibitor and PAI-1 knockdown. Another mechanism of resistance in different subline cells of EBC-1 was evaluated as epithelial-to-mesenchymal transition with the upregulation of antiapoptotic proteins. In H1993-derived resistant cells, MEK inhibitors could be a potential therapeutic strategy for overcoming resistance with downstream mitogen-activated protein kinase pathway activation. In this study, we revealed the different mechanisms of acquired resistance to the MET inhibitor crizotinib with potential therapeutic application in patients with MET-amplified lung carcinoma.

Advances in MET tyrosine kinase inhibitors in gastric cancer.

Gastric cancer is among the most frequently occurring cancers and a leading cause of cancer-related deaths globally. Because gastric cancer is highly heterogenous and comprised of different subtypes with distinct molecular and clinical characteristics, the management of gastric cancer calls for better-defined, biomarker-guided, molecular-based treatment strategies. MET is a receptor tyrosine kinase mediating important physiologic processes, such as embryogenesis, tissue regeneration, and wound healing. However, mounting evidence suggests that aberrant MET pathway activation contributes to tumour proliferation and metastasis in multiple cancer types, including gastric cancer, and is associated with poor patient outcomes. As such, MET-targeting therapies are being actively developed and promising progress has been demonstrated, especially with MET tyrosine kinase inhibitors. This review aims to briefly introduce the role of MET alterations in gastric cancer and summarize in detail the current progress of MET tyrosine kinase inhibitors in this disease area with a focus on savolitinib, tepotinib, capmatinib, and crizotinib. Building on current knowledge, this review further discusses existing challenges in MET alterations testing, possible resistance mechanisms to MET inhibitors, and future directions of MET-targeting therapies.

Current issues of increasing the availability of innovative therapy for the treatment of patients with non-small cell lung cancer within the Russian healthcare system

The advisory board was held to discuss he current situation with diagnosis and treatment of advanced non — small cell lung cancer with a mutation in the MET gene (aNSCLC with METex14). Lung cancer takes a leading place in the structure of oncological diseases in Russia. The frequency of molecular abnormalities in the MET gene patients with advanced lung cancer is 3%, the NGS method is the most effective in identifying this alteration.The effectiveness of capmatinib, a MET tyrosine kinase inhibitor was confirmed in the GEOMETRY mono-1 registry trial: the objective response rate in the patients with aNSCLC with METex14 who had previously received 1–2 lines of therapy was 41%, among those who had not previously received treatment — 68%. Median duration of response was 9.7 month in previously treated patients with aNSCLC with METex14 and 12.6 months in the treatment — naïve patients with aNSCLC with METex14. Intracranial response was observed in 54% of cases among patients with aNSCLC with METex14. In addition, the efficacy of capmatinib was confirmed when it is administered to the patients with aNSCLC with METex14 in real-world clinical practice. Other therapeutic options (immune-oncology therapy, chemotherapy) are less effective in case of this disease variant.Based on the data on effectiveness and tolerability of capmatinib, the expert group made a decision to recommend inclusion of capmatinib in the Russian Clinical Guidelines for the treatment of lung cancer and into the Essential Drug list.

Activating Point Mutations in the MET Kinase Domain Represent a Unique Molecular Subset of Lung Cancer and Other Malignancies Targetable with MET Inhibitors.

Activating point mutations in the MET tyrosine kinase domain (TKD) are oncogenic in a subset of papillary renal cell carcinomas. Here, using comprehensive genomic profiling among >600,000 patients, we identify activating MET TKD point mutations as putative oncogenic driver across diverse cancers, with a frequency of ∼0.5%. The most common mutations in the MET TKD defined as oncogenic or likely oncogenic according to OncoKB resulted in amino acid substitutions at positions H1094, L1195, F1200, D1228, Y1230, M1250, and others. Preclinical modeling of these alterations confirmed their oncogenic potential and also demonstrated differential patterns of sensitivity to type I and type II MET inhibitors. Two patients with metastatic lung adenocarcinoma harboring MET TKD mutations (H1094Y, F1200I) and no other known oncogenic drivers achieved confirmed partial responses to a type I MET inhibitor. Activating MET TKD mutations occur in multiple malignancies and may confer clinical sensitivity to currently available MET inhibitors. Significance: The identification of targetable genomic subsets of cancer has revolutionized precision oncology and offers patients treatments with more selective and effective agents. Here, we demonstrate that activating, oncogenic MET tyrosine kinase domain mutations are found across a diversity of cancer types and are responsive to MET tyrosine kinase inhibitors.

Abstract 4743: Targeting a novel TWIST1-Hexokinase II pathway to overcome MET TKI resistance in NSCLC

Abstract Non-small cell lung cancer (NSCLC) is the most common primary tumor to metastasize to the brain, with up to 40% of NSCLC patients developing brain metastases (BM). These BM portend a poor prognosis, even when extracranial disease is well-controlled. While targeted therapy and immunotherapy have improved lung cancer survival, there are no therapies specifically targeting NSCLC BM. Our lab identified a significant enrichment of MET amplification in lung adenocarcinoma (LUAD) BM (16%) compared to primary NSCLC (3%) and liver metastases (5%). MET, a receptor tyrosine kinase, and its ligand, hepatocyte growth factor (HGF), promote proliferation, epithelial-mesenchymal transition (EMT), angiogenesis, and metastasis. Although MET tyrosine kinase inhibitors (TKIs) are approved for use in METaltered NSCLC, half of patients with MET alterations fail to respond or inevitably acquire TKI resistance. We have found that MET pathway activation by MET alterations leads to increased expression of TWIST1, an EMT transcription factor required for tumorigenesis in MET-dependent NSCLC. Together, the HGF/MET/TWIST1 axis promotes cancer survival and metastasis. We found that MET amplified BM had distinct transcriptional signatures reflecting increased glycolysis. A similar shift toward glycolysis was observed in the MET amplified metastatic LUAD cell line (H1993) compared to the MET wild type primary LUAD line (H2073) derived from the same patient. Furthermore, LUAD cell lines with high MET expression demonstrated increased expression and activity of glycolytic enzymes, as well as increased susceptibility to glucose deprivation and glycolytic inhibitors (2DG, PFK158, AT-101, V-9302). Conversely, treatment of MET amplified cells with MET TKI, capmatinib, reduced glycolysis and oxidation phosphorylation to the levels observed in MET wild type LUAD lines. Activation of the MET pathway with HGF or TWIST1 overexpression specifically increased the mRNA and protein expression of the key glycolytic enzyme, Hexokinase II (HK2), compared to other glycolytic pathway proteins. Conversely, inhibition of the MET pathway with capmatinib or the TWIST1 inhibitor, harmine, decreased HK2 protein expression through a MYC-independent pathway. However, TWIST1 was required for MET-dependent transcriptional upregulation of HK2. Remarkably, in two novel MET altered models (cell line and patient derived xenograft) of acquired MET TKI resistance, TWIST1 and HK2 expression were increased at the time of resistance. Both models remained sensitive to pharmacologic inhibition of either TWIST1 or glycolysis at the time of acquired resistance to MET TKIs. These findings suggest that continued upregulation of the TWIST1-HK2 axis is required for acquired MET TKI resistance. In summary, these studies suggest a targetable, metabolic reprogramming in MET altered LUAD BM mediated through a novel TWIST1-HK2 pathway. Citation Format: Purva H. Rumde, Kasey R. Cargill, Vinod Kumar, Princey Devadassan, Jason Chen, Leviticus McGraw-Sapp, Xiaxuan Wu, Sanja Dacic, Riyue Bao, Bharathri Sivakama, Eric S. Goetzman, Sameer Agnihotri, Steven J. Mullett, Stacey G. Wendell, Laura P. Stabile, Timothy F. Burns. Targeting a novel TWIST1-Hexokinase II pathway to overcome MET TKI resistance in NSCLC [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4743.

Abstract 5867: Early activation of HGF-cMET serves as a bypass pathway to ALK and RET tyrosine kinase inhibitors in non-small cell lung cancer

Abstract Introduction: Alterations of the HGF-cMET axis, often through MET gene amplification, can act as resistance mechanism to tyrosine kinase inhibitors (TKIs) in patients with ALK and RET rearranged non-small cell lung cancer (NSCLC). The efficacy of targeting the cMET pathway through use of MET tyrosine kinase inhibitors continues to evolve. An unresolved question is whether the HGF-cMET pathway is activated early in cancer cells after ALK and RET TKI exposure. Here, we evaluate novel pre-clinical models to better characterize the onset of MET pathway-mediated resistance using murine cell lines and orthotopic murine models. Methods: Murine Eml4-Alk (EA1 and EA3) and Trim24-Ret (TR.1) cell lines were cultured with increasing doses of alectinib (EA1 and EA3) or pralestinib or selpercatinib (TR.1) until resistance was acquired. A cell line was established from an orthotopic TR.1 tumor that progressed on selpercatinib (TR.1-1092). Passage control cells and the TKI-resistant cultures were submitted to clonogenic growth assays in targeting TKI or crizotinib (MET TKI). Control and TKI-resistant cell lines were submitted to HGF ELISA, MET immunoblotting and RNAseq. Orthotopic TR.1 tumors were established in C57BL/6 mice and after ~2 weeks, daily treatment with selpercatinib was performed for 21 days with weekly mCT to monitor tumor size. At 21 days when the tumors were beginning to progress, half the mice were treated with selpercatinib and crizotinib (a MET TKI) while the other half continued on selpercatinib alone. Results: HGF levels (pg/μg) were significantly higher in alectinib-resistant EA1 cells vs. EA3 cells and was associated with retained sensitivity to crizotinib in alectinib-resistant EA1, but not EA3 cells. MET mRNA (but not gene copy number) and HGF mRNA/protein levels in pralsetinib and selpercatinib resistant TR.1 lines were significantly higher than controls and accompanied by acquired sensitivity to crizotinib. In C57BL/6 mice bearing orthotopic TR.1 tumors, the progression on selpercatinib occurring after 2-3 weeks of treatment was reversed in a durable manner by co-treatment with crizotinib. Conclusions: The HGF-cMET axis is activated early in response to ALK and RET TKI exposure through transcriptional mechanisms without evidence of MET gene amplification. These findings unveil a potential therapeutic window to disrupt the MET bypass pathway in ALK and RET rearranged NSCLC prior to overt clinical progression. Citation Format: Tejas Patil, Trista Hinz, Sharon Pine, Hatim Saabawy, Paul Bunn, Erin L. Schenk, Ross Camidge, Lynn Heasley. Early activation of HGF-cMET serves as a bypass pathway to ALK and RET tyrosine kinase inhibitors in non-small cell lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5867.

Abstract 3277: PAI-1 mediates resistance to MET-targeted therapy in non-small cell lung cancer

Abstract [Purpose] The mesenchymal epithelial transition factor receptor (MET) is a potential therapeutic target in various cancers, including non-small cell lung cancer (NSCLC). In NSCLC, the activation of MET pathway is thought to occur through diverse mechanisms that influence properties affecting cancer cell survival, growth, and invasiveness. These tumors show oncogene addiction to MET and exhibit remarkable responses to MET-Tyrosine Kinase Inhibitors (TKIs). However, the long-term effectiveness of MET-TKIs is usually limited due to acquired drug resistance. The mechanisms underlying primary and acquired resistance to MET-TKIs in the management of NSCLC remain unclear. In this study, we investigated the mechanisms acquired for crizotinib in MET-amplified lung carcinoma cell lines. [Experimental Designs] Two MET-amplified lung cancer cell lines, EBC-1 and H1993, were established for acquired resistance to MET-TKI crizotinib and were functionally elucidated. The factors contributing to the resistance mechanism were assessed by genomic and transcriptomic data, and the alterations hypothesized to confer resistance were validated. [Results] Multiple mechanisms underlay acquired resistance to crizotinib in MET-amplified lung cancer cell lines. In EBC-1-derived resistant cells, the drug resistance mechanism was mediated by the overexpression of SERPINE1, the gene encoding plasminogen activator inhibitor-1 (PAI-1). Crizotinib resistance was overcome by combination therapy with PAI-1 inhibitor and PAI-1 knockdown. Another mechanism of resistance in different subline cells of EBC-1 was evaluated as epithelial to mesenchymal transition (EMT) with the upregulation of antiapoptotic proteins. In the H1993-derived resistant cells, the phosphorylated forms of MEK and ERK were observed to be upregulated and MEK inhibitors could be a potential therapeutic strategy for overcoming the resistance. [Conclusions] In this study, we revealed the different mechanisms of drug resistance to MET-TKI treatment and presented some possible strategies to overcome the resistance. Citation Format: Tomoaki Higashihara, Yin Min Thu, Ken Suzawa, Keiichi Date, Atsushi Matsuoka, Daisuke Mizuno, Ryo Yoshichika, Naohiro Hayashi, Fumiaki Mukohara, Mao Yoshikawa, Kazuhiko Shien, Hiromasa Yamamoto, Shinichi Toyooka. PAI-1 mediates resistance to MET-targeted therapy in non-small cell lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3277.

TWIST1 is a critical downstream target of the HGF/MET pathway and is required for MET driven acquired resistance in oncogene driven lung cancer.

MET amplification/mutations are important targetable oncogenic drivers in NSCLC, however, acquired resistance is inevitable and the majority of patients with targetable MET alterations fail to respond to MET tyrosine kinase inhibitors (TKIs). Furthermore, MET amplification is among the most common mediators of TKI resistance. As such, novel therapies to target MET pathway and overcome MET TKI resistance are clearly needed. Here we show that the epithelial-mesenchymal transition (EMT) transcription factor, TWIST1 is a key downstream mediator of HGF/MET induced resistance through suppression of p27 and targeting TWIST1 can overcome resistance. We found that TWIST1 is overexpressed at the time of TKI resistance in multiple MET-dependent TKI acquired resistance PDX models. We have shown for the first time that MET directly stabilized the TWIST protein leading to TKI resistance and that TWIST1 was required for MET-driven lung tumorigenesis as well as could induce MET TKI resistance when overexpressed. TWIST1 mediated MET TKI resistance through suppression of p27 expression and genetic or pharmacologic inhibition of TWIST1 overcame TKI resistance in vitro and in vivo. Our findings suggest that targeting TWIST1 may be an effective therapeutic strategy to overcome resistance in MET-driven NSCLC as well as in other oncogene driven subtypes in which MET amplification is the resistance mechanism.

Targeting the MET gene: unveiling therapeutic opportunities in immunotherapy within the tumor immune microenvironment of non-small cell lung cancer.

Non-small cell lung cancer (NSCLC) represents the most prevalent histological subtype of lung cancer. Within this disease, the MET gene emerges as a critical therapeutic target, exhibiting various forms of dysregulation. Although MET tyrosine kinase inhibitors, HGF/c-MET targeting antibodies, and antibody-drug conjugates constitute the primary treatment modalities for patients with MET-altered NSCLC, numerous questions remain regarding their optimal application. The advent of immunotherapy holds promise for enhancing therapeutic outcomes in patients with MET-altered NSCLC. MET mutations can reshape the tumor immune microenvironment of NSCLC by reducing tumor immunogenicity, inducing exhaustion in immune-activated cells, and promoting immune evasion, which are crucial for modulating treatment responses. Furthermore, we emphasize the promising synergy of immunotherapy with emerging treatments and the challenges and opportunities in refining these approaches to improve patient outcomes.

Abstract PR005: Tepotinib + osimertinib in EGFR-mutant NSCLC with MET amplification following first-line osimertinib: INSIGHT 2 primary analysis

Abstract Introduction: Tepotinib (a MET tyrosine kinase inhibitor) + osimertinib has shown promising efficacy in patients (pts) with EGFR-mutant (EGFRm) MET amplification (METamp) non-small cell lung cancer (NSCLC), who have a high unmet need after progression on first-line (1L) osimertinib. We report the primary analysis of tepotinib + osimertinib from INSIGHT 2 (NCT03940703) in pts with ≥9 months’ follow-up (data-cut: March 28, 2023). Given the higher incidence of EGFRm NSCLC in Asia, outcomes among pts enrolled in Asia are also reported. Methods: In this open-label Phase II study, pts with advanced EGFRm METamp NSCLC following progression on 1L osimertinib received tepotinib 500 mg (450 mg active moiety) + osimertinib 80 mg once daily. METamp was centrally detected by tissue biopsy (TBx) FISH (MET gene copy number [GCN] ≥5 and/or MET/CEP7 ≥2) and/or by liquid biopsy (LBx) next generation sequencing (NGS; MET plasma GCN ≥2.3; Archer®). Primary endpoint was objective response by IRC in pts with central FISH+ METamp. Secondary endpoints included duration of response (DOR), progression-free survival (PFS), and overall survival (OS). Safety is reported for all pts who received ≥1 dose of the combination. Results: Of 481 pts prescreened, 128 received tepotinib + osimertinib (median age 61 years [range 20–84], 57.8% female, 61.7% Asian, 67.2% never smoker, 72.7% ECOG PS 1). In 98 pts with FISH+ METamp, objective response rate (ORR) was 50.0% (95% confidence interval [CI]: 39.7, 60.3). Median (m) DOR was 8.5 months (95% CI: 6.1, not evaluable [ne]) and mPFS was 5.6 months (95% CI: 4.2, 8.1). 76 pts receiving tepotinib + osimertinib were enrolled in Asia. In 52 pts with FISH+ METamp, ORR was 59.6% (95% CI: 45.1, 73.0), mDOR was 7.3 months (95% CI: 4.7, ne), and mPFS was 6.9 months (95% CI: 5.4, 8.4). Outcomes were also meaningful in pts with LBx NGS+ METamp. In the overall population with LBx NGS+ METamp (n=31), ORR was 54.8% (95% CI: 36.0, 72.7), mDOR was 5.7 months (95% CI: 2.9, 15.4) and mPFS was 5.5 months (95% CI: 2.7, 7.2). In pts enrolled in Asia with LBx NGS+ METamp (n=14), ORR was 71.4% (95% CI: 41.9, 91.6), mDOR was 5.6 months (95% CI: 2.9, ne) and mPFS was 5.5 months (95% CI: 4.2, 8.4). In 128 pts treated with tepotinib + osimertinib, the most common treatment-related adverse events (TRAEs) were diarrhea in 63 (49.2%; Grade ≥3, 1 [0.8%]) and peripheral edema in 52 (40.6%; Grade ≥3, 6 [4.7%]) pts. Tepotinib dose was reduced in 27 (21.1%) and osimertinib in four (3.1%) pts. Thirteen pts (10.2%) discontinued treatment due to TRAEs, most often due to pneumonitis (6 [4.7%]). The safety profile of the combination was similar in pts enrolled in Asia. Conclusions: Tepotinib + osimertinib demonstrated durable responses and a manageable safety profile in pts with EGFRm METamp NSCLC following 1L osimertinib, especially in Asian pts. Tepotinib + osimertinib provides a potential chemotherapy-sparing oral targeted therapy option in this population with high unmet need. Citation Format: Xiuning Le, Tae Min Kim, Valentina Guarneri, Pei Jye Voon, Boon Khaw Lim, Jinji Yang, Marie Wislez, Cheng Huang, Chong Kim Liam, Julien Mazieres, Lye Mun Tho, Hidetoshi Hayashi, Nguyen Nhung, Puey Ling Chia, Fillippo De Marinis, Jo Raskin, Qinghua Zhou, Giovanna Finochhiaro, Daniel Tan, Sabine Brutlach, Aurora O'Brate, Svenja Adrian, Karin Berghoff, Barbara Ellers-Lenz, Niki Karachaliou, Yi-Long Wu. Tepotinib + osimertinib in EGFR-mutant NSCLC with MET amplification following first-line osimertinib: INSIGHT 2 primary analysis [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr PR005.

Exploring the interaction of tepotinib with calf thymus DNA using molecular dynamics simulation and multispectroscopic techniques

In recent times, there has been a surge in the discovery of drugs that directly interact with DNA, influencing gene expression. As a result, understanding how biomolecules interact with DNA has become a major area of research. One such drug is Tepotinib (TPT), an FDA-approved anti-cancer medication known as a MET tyrosine kinase inhibitor, used in chemotherapy for metastatic non-small cell lung cancer (NSCLC) with MET exon 14 skipping alterations. In our study, we adopted both biophysical and in-silico methods to investigate the binding relationship of TPT and ctDNA. The absorption spectra of ctDNA exhibited a hypochromic effect when titrated with TPT and the binding constant of TPT–ctDNA complex was calculated, Ka = 9.91 × 104 M−1. By computing bimolecular enhancement constant (KB) and thermodynamic enhancement constant (KD) in fluorometric investigations, it was found that the fluorescence enhancement is a result of a static process involving the ctDNA-TPT complex formation in the ground state, as opposed to a dynamic process. The displacement assay results further supported this finding, showing that TPT exhibits a binding preference for minor groove of ct-DNA and was also demonstrated by KI quenching and CD spectroscopy. The molecular docking and molecular dynamic simulations validated TPT's groove binding nature and binding pattern with ctDNA, respectively. Thus, the results of our present investigation offer valuable insights into the interaction between TPT and ctDNA. It is evident that TPT, as an anti-cancer medication, binds to the minor groove of ctDNA.

Drug Resistance Mechanism and Therapeutic Strategy of Targeted Therapy of Non-small Cell Lung Cancer with MET Alterations

Mesenchymal to epithelial transition factor (MET) gene alterations involve in the proliferation, invasion, and metastasis of non-small cell lung cancer. MET-tyrosine kinase inhibitors (TKIs) have been approved to treat non-small cell lung cancer with MET alterations, and resistance to these TKIs is inevitable. Molecular mechanisms of resistance to MET-TKIs are completely unclear. The review focused on potential mechanisms of MET-TKIs resistance and therapeutics strategies to delay and prevent resistance. .

Programmed Cell Death Protein 1 Inhibitors and MET Targeted Therapies in NSCLC With MET Exon 14 Skipping Mutations: Efficacy and Toxicity as Sequential Therapies

IntroductionNSCLC with MET exon 14 skipping mutation (METex14) is associated with poor outcomes. Integration of novel targeted therapies is challenging because of barriers in testing and drug access. We, therefore, sought to characterize the treatment patterns, outcomes, and emerging issues of treatment sequencing in patients with METex14-mutant NSCLC. MethodsWe reviewed all NSCLC cases with METex14 alterations between 2014 and 2020 across four Canadian cancer centers. Demographics, disease characteristics, systemic therapy, overall response rates (ORRs), survival, and toxicity were summarized. ResultsAmong 64 patients with METex14-mutant NSCLC, the median overall survival was 23.1 months: 127.0 months in stage 1, 27.3 months in resected stage 2 and 3, and 16.6 months in unresectable stage 3 or 4 disease, respectively. In patients with advanced disease, 22% were too unwell for systemic treatment. MET tyrosine kinase inhibitors (TKIs) were administered to 28 patients with an ORR of 33%, median progression-free survival of 2.7 months, and 3.8 months for selective TKIs. Programmed cell death protein-1 (PD-1) inhibitors were given to 25 patients—the ORR was 44% and progression-free survival was 10.6 months. No responses were seen with subsequent MET TKIs after initial TKI treatment. Grade 3 or higher toxicities occurred in 64% of patients who received MET TKI after PD-1 inhibitors versus 8% in those who did not receive PD-1 inhibitors. ConclusionsMany patients with advanced METex14 NSCLC were too unwell to receive treatment. PD-1 inhibitors seem effective as an initial treatment, although greater toxicity was seen with subsequent MET TKIs. Thus, timely testing for METex14 skipping and initial therapy are imperative to improving patient survival.

MET exon 14 skipping mutation is a hepatocyte growth factor (HGF)-dependent oncogenic driver in vitro and in humanized HGF knock-in mice.

Exon skipping mutations of the MET receptor tyrosine kinase (METex14), increasingly reported in cancers, occur in 3-4% of non-small cell lung cancer (NSCLC). Only 50% of patients have a beneficial response to treatment with MET-tyrosine kinase inhibitors (TKIs), underlying the need to understand the mechanism of METex14 oncogenicity and sensitivity to TKIs. Whether METex14 is a driver mutation and whether it requires hepatocyte growth factor (HGF) for its oncogenicity in a range of in vitro functions and in vivo has not been fully elucidated from previous preclinical models. Using CRISPR/Cas9, we developed a METex14/WT isogenic model in non-transformed human lung cells, and report that the METex14 single alteration was sufficient to drive MET-dependent in vitro anchorage-independent survival and motility and in vivo tumorigenesis, sensitising tumours to MET-TKIs. However, we also show that human HGF (hHGF) is required, as demonstrated in vivo using a humanized HGF knock-in strain of mice and further detected in tumor cells of METex14 NSCLC patient samples. Our results also suggest that METex14 oncogenicity is not a consequence of an escape from degradation in our cell model. Thus, we developed a valuable model for preclinical studies and present results that have potential clinical implication.

MET Fusions in NSCLC: Clinicopathologic Features and Response to MET Inhibition

IntroductionMET fusions have been described only rarely in NSCLC. Thus, data on patient characteristics and treatment response are limited. We here report histopathologic data, patient demographics, and treatment outcome including response to MET tyrosine kinase inhibitor (TKI) therapy in MET fusion-positive NSCLC. MethodsPatients with NSCLC and MET fusions were identified mostly by RNA sequencing within the routine molecular screening program of the national Network Genomic Medicine, Germany. ResultsWe describe a cohort of nine patients harboring MET fusions. Among these nine patients, two patients had been reported earlier. The overall frequency was 0.29% (95% confidence interval: 0.15–0.55). The tumors were exclusively adenocarcinoma. The cohort was heterogeneous in terms of age, sex, or smoking status. We saw five different fusion partner genes (KIF5B, TRIM4, ST7, PRKAR2B, and CAPZA2) and several different breakpoints. Four patients were treated with a MET TKI leading to two partial responses, one stable disease, and one progressive disease. One patient had a BRAF V600E mutation as acquired resistance mechanism. ConclusionsMET fusions are very rare oncogenic driver events in NSCLC and predominantly seem in adenocarcinomas. They are heterogeneous in terms of fusion partners and breakpoints. Patients with MET fusion can benefit from MET TKI therapy.

MET Receptor Tyrosine Kinase Inhibition Reduces Interferon-Gamma (IFN-γ)-Stimulated PD-L1 Expression through the STAT3 Pathway in Melanoma Cells.

Melanoma is the leading cause of death from cutaneous malignancy. While targeted therapy and immunotherapy with checkpoint inhibitors have significantly decreased the mortality rate of this disease, advanced melanoma remains a therapeutic challenge. Here, we confirmed that interferon-gamma (IFN-γ)-induced PD-L1 expression in melanoma cell lines. This increased expression was down-regulated by the reduction in phosphorylated STAT3 signaling via MET tyrosine kinase inhibitor treatment. Furthermore, immunoprecipitation and confocal immunofluorescence microscopy analysis reveals MET and PD-L1 protein-protein interaction and colocalization on the cell surface membrane of melanoma cells. Together, these findings demonstrate that the IFN-γ-induced PD-L1 expression in melanoma cells is negatively regulated by MET inhibition through the JAK/STAT3 signaling pathway and establish the colocalization and interaction between an RTK and a checkpoint protein in melanoma cells.