MET Tyrosine Kinase Inhibitors Research Articles

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.

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.

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.

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.

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.

Tepotinib + osimertinib for EGFR mutant (EGFRm) NSCLC with MET amplification (METamp) after first-line (1L) osimertinib.

9021 Background: METamp is a common resistance mechanism developed in patients (pts) with EGFRm NSCLC treated with osimertinib. MET tyrosine kinase inhibitors (TKIs) such as tepotinib may be effective in treating these pts after osimertinib. Here we report interim data from the INSIGHT 2 study evaluating tepotinib + osimertinib in EGFRm NSCLC with METamp previously treated with osimertinib. Methods: In this open-label Phase II study (INSIGHT 2, NCT03940703), pts with advanced EGFRm NSCLC with METamp after progression on 1L osimertinib received tepotinib 500 mg (450 mg active moiety) + osimertinib 80 mg once daily. METamp was centrally detected in tissue biopsy (TBx) by FISH ( MET gene copy number [GCN] ≥5 and/or MET/ CEP7 ≥2) and/or in liquid biopsy (LBx) by NGS ( MET plasma GCN ≥2.3; Archer). The primary endpoint was objective response by Independent Review Committee in tepotinib + osimertinib treated pts with centrally detected METamp by FISH (FISH+). Efficacy data are reported for pts with ≥3 months’ follow-up, and safety for all pts who received one dose of tepotinib + osimertinib by Sep 26, 2022 (data cut-off). Results: Among 472 pts prescreened, 451 pts had METamp results by either TBx FISH and/or LBx NGS, of which 175 (38.8%) were positive for METamp. 122 pts received tepotinib + osimertinib (median age 61 years [range 20–84], 59.8% female, 59.8% Asian, 68.0% never smoker, 72.1% ECOG PS 1). In 98 pts with FISH METamp (29.6% had < 12 months on 1L osimertinib; median GCN 11 [range 5.0–50.6]; mean ± SD sum of target lesion diameters [SOLD] 73.2 ± 47.1 mm), objective response rate (ORR) was 43.9% (95% CI 33.9, 54.3), median (m) DOR was 9.7 months (95% CI 5.6, ne), mPFS was 5.4 months (95% CI 4.2, 7.1), and mOS was not reached (95% CI 11.1, ne). Of the 98 pts, treatment is ongoing in 42 pts. In 31 pts with METamp detected by LBx NGS, of which 24 were also FISH+ (mean ± SD SOLD 93.9 ± 51.4 mm), ORR was 51.6% (95% CI 33.1, 69.8), mDOR was 5.6 months (95% CI 2.9, ne), mPFS was 4.6 months (95% CI 2.7, 6.9), and mOS was not reached (95% CI 6.8, ne). Of 122 pts treated with tepotinib + osimertinib, any grade treatment-related AEs were reported by 99 (81.1%) pts including 34 (27.9%) Grade ≥3. Most common ( > 15% pts) treatment-related AEs included diarrhea 46.7% (0% Grade ≥3), peripheral edema 34.4% (4.1% Grade ≥3), paronychia 20.5% (0.8% Grade ≥3), decreased appetite 18.0% (3.3% Grade ≥3), and nausea 16.4% (1.6% Grade ≥3). Treatment-related AEs led to a dose reduction in 21 (17.2%) pts, following either or both treatments and led to treatment discontinuation in 7 pts (5.7%). Conclusions: In this interim analysis of INSIGHT 2, tepotinib + osimertinib was highly active with durable responses, and was well tolerated in pts with EGFRm NSCLC with METamp after progression on 1L osimertinib. Tepotinib + osimertinib provides a potential chemotherapy-sparing oral targeted therapy option in this population with a high unmet need. Clinical trial information: NCT03940703 .

Biomarker testing and treatment patterns in US patients (pts) with advanced/metastatic non-small cell lung cancer (NSCLC) harboring MET amplification.

e21057 Background: Limited published evidence exists on pts with advanced stage NSCLC harboring MET amplification ( METamp), a rare oncogenic driver. We report here real-world biomarker testing and treatment patterns for these patients. Methods: This was a non-interventional, descriptive cohort study using ConcertAI electronic medical record data derived from US community oncology centers and linked with ASCO/CancerLinQ data. Eligible pts had stage IIIB–IV NSCLC and METamp. Study period: Jan 1, 2004 – Oct 31, 2021. Results: Of 8,454 lung cancer pts with minimum 1 molecular test including MET, 164 had METamp (1.9%). Pts were mainly identified from 2015 onwards and primarily in oncology in the Southern and Midwest regions (86.6%). Majority of pts were tested by tissue biopsy (67.1%), 20.7% by liquid biopsy and 12.2% not specified. At least 64.5% of pts were highly MET amplified (either gene copy number ≥8 or by liquid biopsy ++, +++). Other mutations screened for were ALK, ROS1 and EGFR (99.4%, 98.2% and 97.6%), with oncogenic ALK, ROS1 fusions and activating EGFR mutations in 0.6% and 13.1%, respectively. BRAF and KRAS were less frequently screened for (90.2% and 87.2%), with potential oncogenic alterations in 2.0% and 12.6%. Of 127 pts tested for PD-L1 (by immunohistochemistry), 63.0% were positive, and 72.5% had tumor proportion score ≥50. Eighteen pts had METamp detected after receiving an EGFR tyrosine kinase inhibitor (TKI), indicating METamp as a secondary oncogenic driver. RB1 loss and MYC amplification, as potential mechanisms of MET inhibition resistance, were not frequently screened for (30.5% and 46.3%). RB1 loss was identified in 2.0% and MYC amplification in 15.8%. Next generation sequencing was the most frequent diagnostic used overall. A total of 144 pts (87.8% of 164 pts) received first-line (1L) anticancer therapy; platinum-based chemotherapy 57/144 (39.6%), immune-checkpoint inhibitors 50/144 (34.7%) or EGFR TKI monotherapy 24/144 (16.7%), other 2/144 (1.4%) and MET TKIs (mainly crizotinib) were used in 11/144 pts (7.6%) in 1L, 14/78 (17.9) in second line and 7/42 (16.7%) in third line. Conclusions: In this cohort of pts identified in a US community oncology setting, biomarker screening even for rarer genetic alterations occurred. Concomitant genetic alterations to METamp were infrequent except for alterations of EGFR and KRAS. The frequency of pts with high level of METamp in the cohort may explain the lower frequency of other biomarkers, as high level of amplification indicates a cleaner MET profile. Overall MET inhibitor treatment was not common. Screening for novel and rare biomarkers such as METamp as a primary or secondary oncogenic driver is becoming increasingly important to enable efficacious targeted treatment.

Phase 1 multicenter dose escalation and dose expansion study of antibody-drug conjugate (ADC) MYTX-011 in subjects with non-small cell lung cancer.

TPS9147 Background: cMET is a receptor tyrosine kinase and proto-oncogene whose activity is upregulated across a wide range of cancers. In NSCLC, expression of cMET is upregulated by DNA amplification (2% to 5%), exon 14 skipping mutations (2% to 4%), and overexpression (30% to 60%). In NSCLC, cMET upregulation has also been demonstrated to be a resistance mechanism for several approved EGFR-targeted kinase inhibitors, and this may limit their effectiveness. Despite the approval of MET tyrosine kinase inhibitors, almost half of patients do not respond to these inhibitors and resistance is inevitable. MYTX-011 is an ADC incorporating the clinically validated vcMMAE linker-payload conjugated to a novel, pH-dependent anti-cMET antibody. In preclinical studies, MYTX-011, compared to a surrogate of an advanced clinical stage cMET ADC, showed markedly higher ( > 3 fold) internalization and increased cytotoxicity in cMET+ tumor cells in vitro, which translates to greater (≥3 fold) efficacy in high or moderate c-Met+ xenograft models in vivo. PK and toxicity studies revealed that MYTX-011 exhibited favorable PK characteristics, and a toxicity profile similar to previously described MMAE-based ADCs. Methods: MYTX-011-01 (ClinicalTrials.gov Identifier: NCT05652868) is a first-in-human Phase 1 dose escalation and dose expansion study. MYTX-011 will be administered intravenously every 21 days for a maximum of 2 years. Part 1 (dose escalation) will assess the safety and tolerability of MYTX-011 in patients with advanced NSCLC and identify the recommended Phase 2 dose (RP2D). Part 2 (dose expansion) will include subjects with NSCLC with cMET overexpression or MET amplification/exon 14 skipping mutations. In Part 1, subjects will be enrolled to evaluate the safety of escalating doses of MYTX-011 as a single-agent and to establish the RP2D and/or MTD. The dose escalation scheme is based on a 3-subject cohort minimum Bayesian Optimal Interval (BOIN) design. The RP2D will be selected as a biologically active dose at or below the MTD (or the highest dose tested if an MTD is not identified during the study) and will be informed by safety, tolerability, pharmacokinetic data, and preliminary anti-tumor activity of MYTX-011 based on RECIST 1.1. Part 2 of the study will be initiated once the RP2D has been determined and will enroll subjects into different cohorts based on cMET IHC positivity cutoff and/or presence of MET genetic alterations ( MET amplification or exon 14 skipping). All cohorts are defined to explore preliminary antitumor activity in populations with different thresholds of cMET positivity that were selected based on data for cMET expression and efficacy observed with MYTX-011 in preclinical models, published data for responses to cMET targeting agents, and on the prevalence of subject tumors with different expression levels. Enrollment in the MYTX-011-01 study is ongoing. Clinical trial information: NCT05652868 .

Phase II study of crizotinib in patients with MET amplification and MET exon 14 deletion: Results from NCI-MATCH ECOG-ACRIN trial (EAY131) subprotocols C1 and C2.

3108 Background: The NCI-Molecular Analysis for Therapy Choice (MATCH) platform trial enrolled patients with solid tumors, lymphomas, or multiple myeloma to trials of targeted therapies based on matching genomic alterations. Subprotocols C1 and C2 evaluated MET tyrosine kinase inhibitor crizotinib in pts with MET amplification ( METamp; C1) or MET Exon 14 mutation/deletion ( METex14; C2). Methods: Pts whose tumors had METamp or METex14 were eligible for C1 and C2, respectively. Results were confirmed by MATCH Oncomine assay if possible; C2 explored METex14 quantification at DNA level retrospectively using cases with sufficient tissue for analysis of DNA mutations surrounding MET exon 14 and control samples with a variable amount of MET exon 14 counts using Anchored Multiplex PCR. Pts in C1 and C2 received crizotinib orally BD daily in 28-day cycles until progression or unacceptable toxicity. Tumor assessment occurred every 2 cycles. Primary endpoint was ORR; PFS; secondary endpoints: 6-month PFS, OS, and predictive biomarkers. Results: C1 enrolled 44 pts, of which 28, representing a variety of histologies, were eligible, received treatment, and included in the primary efficacy analysis as prespecified by protocol; GI (n=17) and lung (n=7) were most common. Median age: 67 (range 28- 82), 9 pts were women. Median MET copy number was 16.8 (min 7.1, max 78.0). Of 28 pts, 4 had PR; 10 had SD, 13 had PD as best response; disease control rate (DCR) 50% (14/28); one pt was unevaluable. ORR was 14% (4/28, 90% CI: 5.0%-29.8%). Median PFS was 3.4 mo (90% CI: 1.8–3.7); median OS 7.1 mo (90% CI: 5.0–11.5). 4 pts with confirmed PR were lung (n=2), GI (n=1), melanoma (n=1); 1 pt had SD >6 mo (NSCLC). Most pts had ≥1 co-occurring gene alteration (n=27; 96%), TP53 co-mutation most frequently (n=23, 82%); 21 pts had ≥3 co-occurring mutations. C2 enrolled 20 pts, 14 evaluable received treatment: GI (n=5); lung (n=6); other (n=3). Median age for the 14 pts was 68 (range 57-78); 6 pts were women, 9 (64%) had ≥3 lines of prior therapy. Most pts had ≥1 co-occurring gene alteration (n=13; 93%, range 1-4); TP53 co-mutations were frequent (n=7, 50%). Of 14 pts, 2 had PR (both NSCLC); 4 had SD, 4 had PD as best response, and DCR was 43% (6/14). 2 pts had SD >6 mo (1 lung, 1 bladder). ORR was 14% (2/14, 90% CI: 2.6%-38.5%). Median PFS 2.0 mo (90% CI: 1.4–4.1). On quantification by Met count ≥50,000 mPFS 8.8 months (90% CI: 2.1–NA), MET count <50,000 mPFS 1.7 mo (90% CI: 1.1–3.7). All lung cancer pts with confirmed PR/SD >6 mo had documented MET count >50,000. Most common reason for permanent treatment discontinuation was disease progression. No new toxicity signals were identified. Conclusions: We demonstrate clinical activity using crizotinib across tumors in patients with METampand METex14. In METex14, differentiating true pathogenic variants from low-level splice variant transcripts may be clinically meaningful. Clinical trial information: NCT02465060 .

Chinese multidisciplinary expert consensus on the management of adverse drug reactions associated with savolitinib

MET gene is a proto-oncogene, which encodes MET protein with tyrosine kinase activity. After binding to its ligand, hepatocyte growth factor, MET protein can induce MET dimerization and activate downstream signaling pathways, which plays a crucial role in tumor formation and metastasis. Savolitinib, as a specific tyrosine kinase inhibitor (TKI) targeting MET, selectively inhibits the phosphorylation of MET kinase with a significant inhibitory effect on tumors with MET abnormalities. Based on its significant efficacy shown in the registration studies, savolitinib was approved for marketing in China on June 22, 2021 for the treatment of advanced non-small cell lung cancer with MET 14 exon skipping mutations. In addition, many studies have shown that MET TKIs are equally effective in patients with advanced solid tumors with MET gene amplification or MET protein overexpression, and relevant registration clinical studies are ongoing. The most common adverse reactions during treatment with savolitinib include nausea, vomiting, peripheral edema, pyrexia, and hepatotoxicity. Based on two rounds of extensive nationwide investigations to guide clinicians, the consensus is compiled to use savolitinib rationally, prevent and treat various adverse reactions scientifically, and improve the clinical benefits and quality of life of patients. This consensus was prepared under the guidance of multidisciplinary experts, especially including the whole-process participation and valuable suggestions of experts in Traditional Chinese Medicine, thus reflecting the clinical treatment concept of integrated Chinese and western medicines.

Abstract 3918: Kinase domain duplications of FGFR1 and MET are potential therapeutic targets

Abstract Background: Kinase domain duplication (KDD) is recently recognized as an oncogenic driver. Therapeutic potential has been established in EGFR-KDDs in non-small cell lung cancer, and our group recently showed resistance mechanism in lung cancers harboring EGFR-KDDs treated with EGFR tyrosine kinase inhibitors (TKIs). However, the frequency and oncogenic role of KDDs in other receptor tyrosine kinases has been elusive. Methods: To investigate the frequency of KDDs in advanced cancer patients, we developed in-house algorithm to detect KDDs in high-depth panel sequencing dataset and evaluated its performance using large-scale panel sequencing data from Seoul National University Hospital (SNUH). In short, the algorithm collects reads with soft clips from a modified GATK best practice pipeline for clinical NGS data processing. The collected reads are then grouped according to their matched position and insert size, and evidences of each group (number of splitting and spanning reads) are collected to yield a set of initial candidates. Finally, the initial candidates were manually inspected after quality control by removing false-positive candidates, such as non-target genes or consistent findings. Then, we established cell lines transfected with KDDs of FGFR1 and MET to validate oncogenic role of identified KDDs in the cohort. Using these transformed cell lines, we investigated carcinogenicity with cell viability assay, immunoblot assay and colony formation assay. FGFR TKIs and MET TKIs were used to uncover the possibility of therapeutic targets in the KDDs. Results: Using the in-house algorithm, we identified FGFR1-KDDs from brain tumors (n=4), EGFR-KDDs from lung (n=1) and brain (n=2) tumors, and MET-KDD from a lung tumor (n=1) in a total of 3,932 cancer samples, with 0.2% frequency. All three kinds of KDDs contained full-length of kinase domains of each gene. Ba/F3 cells transfected with the FGFR1-KDD constructs proliferated well without IL-3 (1239- and 1019-fold higer than wild-type FGFR1), while wild-type FGFR1 Ba/F3 cells did not. This growth potential was diminished by FGFR TKIs BGJ398 (IC50, 0.063 ± 0.065nM), PD173074 (IC50, 1.498 ± 1.021nM), and ponatinib (IC50, 5.69 ± 3.05nM). Reduced expressions of downstream pathway proteins including phospho-FGFR1, phospho-Akt, and phospho-Erk were confirmed by immunoblot assays. NIH-3T3 cells transfected with MET-KDD construct also showed growth advantage compared to wild-type MET NIH-3T3 cells. Capmatinib, a MET TKI, inhibited colony formation of MET-KDD NIH-3T3 cells with reduced phospho-MET expression. Conclusion: In this study, we validated newly developed KDD-detection computational methods using targeted DNA sequencing data. Using this algorithm, we found 0.2% of KDDs in 3,932 cancer samples, including EGFR, FGFR1, and MET. In addition to EGFR-KDDs, our study reveals that both FGFR1- and MET-KDD can be oncogenic and therapeutic targets in brain and lung cancer patients. Citation Format: Chaelin Lee, Sungyoung Lee, Hongseok Yun, Jeonghwan Youk, Tae Min Kim, Soyeon Kim, Bhumsuk Keam, Miso Kim, Dong-Wan Kim. Kinase domain duplications of FGFR1 and MET are potential therapeutic targets. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3918.