Phase II study investigating the efficacy and safety of glesatinib (MGCD265) in patients with advanced NSCLC containing MET activating alterations

OBJECTIVES

Dysregulated signaling by mesenchymal epithelial transition factor (MET) and heightened AXL activation are implicated in the pathogenesis of non-small cell lung cancer (NSCLC). Glesatinib (MGCD265) is an investigational, oral inhibitor of MET and AXL.

MATERIALS AND METHODS

This open-label, Phase II study investigated glesatinib (free-base suspension [FBS] capsule 1050 mg BID or spray-dried dispersion [SDD] tablet 750 mg BID) in patients with advanced, previously treated NSCLC across four cohorts grouped according to presence of MET activating mutations or amplification in tumor or ctDNA. The primary endpoint was objective response rate (ORR).

RESULTS

Sixty-eight patients were enrolled: n = 28 and n = 8 with MET exon 14 skipping mutations in tumor tissue and ctDNA, respectively, and n = 20 and n = 12 with MET gene amplification in tumor tissue and ctDNA, respectively. Overall, ORR was 11.8 %, median progression-free survival was 4.0 months, and median overall survival was 7.0 months. Among patients with MET activating mutations, ORR was 10.7 % with tumor testing and 25.0 % with ctDNA testing. For MET amplification, responses were observed only in patients enrolled by tumor testing (ORR 15.0 %). Diarrhea (82.4 %), nausea (50.0 %), increased alanine aminotransferase (41.2 %), fatigue (38.2 %), and increased aspartate aminotransferase (36.8 %) were the most frequent adverse events assessed as related to study medication. Glesatinib exposure was similar with the SDD tablet and FBS capsule formulations. The study was terminated early by the sponsor due to modest clinical activity.

CONCLUSIONS

Glesatinib had an acceptable safety profile in patients with advanced, pre-treated NSCLC with MET activating alterations. Modest clinical activity was observed, which likely reflects suboptimal drug bioavailability suggested by previously reported Phase I data, and pharmacodynamic findings of lower than anticipated increases in circulating soluble shed MET ectodomain (s-MET).

Durable response to amivantamab in treatment refractory NSCLC harboring EGFR and complex MET mutations: A case report

Targeted therapies have revolutionized treatment for metastatic non-small cell lung cancer (NSCLC) with oncogenic driver mutations. However, challenges arise in managing concurrent mutations and overcoming resistance. We present the case of a patient with epidermal growth factor receptor (EGFR) (L747_A750delinsP exon19 deletion) and mesenchymal-epithelial transition factor (MET) mutations (D1228H, D1228N, D1228Y, Y1230H, MET amplification) who achieved a durable response to amivantamab (14 months ongoing) after progression on multiple lines of therapy including platinum-based chemotherapy, EGFR tyrosine kinase inhibitors (TKI) and combination TKI and MET inhibitors. This case highlights the utility of longitudinal next-generation sequencing (NGS) testing to identify acquired resistance and the need for continued research into understanding mechanisms of resistance to help develop future treatment strategies.

Targeting the hedgehog pathway in MET mutation cancers and its effects on cells associated with cancer development

The mutation of MET plays a crucial role in the initiation of cancer, while the Hedgehog (Hh) pathway also plays a significant role in cell differentiation and the maintenance of tumor stem cells. Conventional chemotherapy drugs are primarily designed to target the majority of cell populations within tumors rather than tumor stem cells. Consequently, after a brief period of remission, tumors often relapse. Moreover, the exclusive targeting of tumor stemness cell disregards the potential for other tumor cells to regain stemness and acquire drug resistance. As a result, current drugs that solely target the HGF/c-MET axis and the Hh pathway demonstrate only moderate efficacy in specific types of cancer. Mounting evidence indicates that these two pathways not only play important roles in cancer but also exert significant influence on the development of resistance to single-target therapies through the secretion of their own ligands. In this comprehensive review, we analyze and compare the potential impact of the Hh pathway on the tumor microenvironment (TME) in HGF/c-MET-driven tumor models, as well as the interplay between different cell types. Additionally, we further substantiate the potential and necessity of dual-pathway combination therapy as a critical target in MET addicted cancer treatment. Video Abstract.

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

Background

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

Methods

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

Findings

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

Interpretation

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

Funding

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

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

Background:

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

Methods:

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

Results:

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

Conclusions:

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

A lung adenocarcinoma patient with co-mutations of MET and EGFR exon20 insertion responded to crizotinib

Background

Targeted therapy has revolutionized the treatment of patients with malignancies harboring mutations in driver genes and has brought a favorable survival benefit to the population with actionable oncogenic mutations. In recent years, the MET exon14 skipping mutation has been recognized as a potentially promising therapeutic target in non-small cell lung cancer (NSCLC). These changes are mutually exclusive with molecular drivers such as EGFR, KRAS, HER-2, BRAF, ALK and ROS1. The prevalence rate of coexisting MET exon 14 mutations and EGFR sensitive mutations (L858R, exon 19 deletions) in Chinese population was reported to be 0.2% (3/1590). However, the coexistence of MET exon 14 mutations with EGFR exon 20 insertion mutations has never been reported and the management of this subtype is not identified.

Case presentation

A 69-year-old male with a right lung adenocarcinoma (T4N2M0, IIIB) was confirmed to be positive for MET exon 14 skipping (c.3028_3028+1delGGinsTT, 44.4%), MET amplification (copy number 4.4), and EGFR exon 20 insertion (p. N771_H773dup, 22.1%) mutations. After the progression of one cycle of chemotherapy (Pemetrexed 0.8 g d1), the patient was subsequently accepted treatment with Crizotinib (250 mg twice a day) and achieved an important clinical remission for six months until the development of brain metastases. Then, he was submitted to a cycle of anti-programmed cell death-1 (PD-1) therapy after failure of Crizotinib and eventually acquired resistance despite of the high expression of programmed death ligand-1 (PD-L1) and tumor mutational burden (TMB) status.

Conclusion

This case report provides treatment strategies for epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs)-untreated lung adenocarcinoma patients simultaneously carrying MET alterations and EGFR exon 20 insertion mutations. In addition, the signatures of PD-L1 or TMB expression were not the candidate for predicting the efficacy of immunotherapy in this context.

MET Mutation Is a Potential Therapeutic Target for Advanced Endometrial Cancer

Simple Summary

Endometrial cancer is the most common gynecological cancer in developed countries. At initial diagnosis, extra-uterine spread is observed in about 25% of patients. Chemotherapy is the suggested mode of treatment for patients with extra-uterine metastasis; however, the 5-year overall survival rate of these patients remains poor. The development of new therapeutic strategies to improve the poor clinical outcome of patients with advanced endometrial cancer is still in great demand. In this study, we aim to understand the genomic landscape of advanced endometrial cancer and identify new therapeutic targets. Integrated genomic, pathological, and clinical data are analyzed to identify the survival-associated genomic alterations. In addition, the impacts of the genomic alterations are examined in silico, in vitro, and in vivo. The results of this study may aid in developing biomarker-guided treatments for patients with advanced endometrial cancer.

Abstract

An optimal therapeutic regimen for endometrial cancer with extra-uterine metastasis is unavailable. This study aims to improve our understanding of the genomic landscape of advanced endometrial cancer and identify potential therapeutic targets. The clinical and genomic profiles of 81 patients with stage III or IV endometrial cancer were integrated. To identify genomic aberrations associated with clinical outcomes, Cox proportional hazard regression was used. The impacts of the genomic aberrations were validated in vitro and in vivo. The mutation status of MET, U2AF1, BCL9, PPP2R1A, IDH2, CBL, BTK, and CHEK2 were positively correlated with poor clinical outcomes. MET mutations occurred in 30% of the patients who presented with poor overall survival (hazard ratio, 2.606; 95% confidence interval, 1.167~5.819; adjusted p-value, 0.067). Concurrent MET and KRAS mutations presented with the worst outcomes. MET mutations in hepatocyte growth factor (HGF)-binding (58.1%) or kinase (16.2%) domains resulted in differential HGF-induced c-MET phosphorylation. Different types of MET mutations differentially affected tumor growth and displayed different sensitivities to cisplatin and tyrosine kinase inhibitors. MET N375S mutation is a germline variant that causes chemoresistance to cisplatin, with a high incidence in Eastern Asia. This study highlights the ethnic differences in the biology of the disease, which can influence treatment recommendations and the genome-guided clinical trials of advanced endometrial cancer.

Development of metastatic poorly differentiated thyroid cancer from a sub-centimeter papillary thyroid carcinoma in a young patient with a germline MET mutation - association or random chance?

Background

Thyroid cancer dedifferentiation is an unusual observation among young patients and is poorly understood, although a recent correlation to DICER1 gene mutations has been proposed.

Case presentation

A 28-year old patient presented with a sub-centimeter cytology-verified primary papillary thyroid carcinoma (PTC) and a synchronous lateral lymph node metastasis. Following surgery, histopathology confirmed a 9 mm oxyphilic PTC and a synchronous metastasis of poorly differentiated thyroid carcinoma (PDTC). Extensive molecular examinations of both lesions revealed wildtype DICER1 sequences, but identified a somatic ETV6-NTRK3 gene fusion and a MET germline variant (c.1076G > A, p.Arg359Gln). MET is an established oncogene known to be overexpressed in thyroid cancer, and this specific alteration was not reported as a single nucleotide polymorphism (SNP), suggestive of a mutation. Both the primary PTC and the metastatic PDTC displayed strong MET immunoreactivity. A validation cohort of 50 PTCs from young patients were analyzed using quantitative real-time PCR, revealing significantly higher MET gene expression in tumors than normal thyroid controls, a finding which was particularly pronounced in BRAF V600E mutated cases. No additional tumors apart from the index case harbored the p.Arg359Gln MET mutation. Transfecting PTC cell lines MDA-T32 and MDA-T41 with a p.Arg359Gln MET plasmid construct revealed no obvious effects on cellular migratory or invasive properties, whereas overexpression of wildtype MET stimulated invasion.

Conclusions

The question of whether the observed MET mutation in any way influenced the dedifferentiation of a primary PTC into a PDTC metastasis remains to be established. Moreover, our data corroborate earlier studies, indicating that MET is aberrantly expressed in PTC and may influence the invasive behavior of these tumors.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13044-021-00110-4.

Budget impact of capmatinib for adults with metastatic non-small cell lung cancer harboring a MET exon 14 skipping mutation in the United States

AIMS

To estimate the budget impact of adding capmatinib, the first FDA approved MET inhibitor, to a US commercial or Medicare health plan for patients with metastatic non-small cell lung cancer (mNSCLC) whose tumors have a mutation that leads to MET exon 14 (METex14) skipping.

METHODS

Target population size was estimated using published epidemiology data. Clinical data were obtained from the GEOMETRY mono-1 capmatinib trial and published trials. Treatments in the market mix included crizotinib, pembrolizumab, ramucirumab, and chemotherapy. Uptake of capmatinib and testing rates were based on market research. All costs (drug acquisition and administration, pre-progression, progression, terminal care, adverse event, and testing) were estimated based on public sources (2020 USD).

RESULTS

The number of patients eligible for capmatinib in the first three years was estimated to be 2-3 in a hypothetical 1 million member commercial plan and 34-44 in a hypothetical 1 million member Medicare plan each year. The estimated total budget impact ranged from $9,695 to $67,725 for a commercial plan and $141,350 to $985,695 for Medicare. With capmatinib included, a marginal per member per month budget impact was estimated (commercial: $0.0008 to $0.0056; Medicare: $0.0118 to $0.0821). Capmatinib inclusion resulted in lower medical costs (commercial: -$0.0003 to -$0.0007; Medicare: -$0.0037 to -$0.0106), partially offsetting increased drug costs ($0.0011 to $0.0064; $0.0154 to $0.0928, respectively), and were primarily driven by reductions in progression and terminal care costs (-$0.0003 to -$0.0009; -$0.0037 to -$0.0125, respectively). The results were most sensitive to capmatinib market share, capmatinib price, and treatment duration.

LIMITATIONS

Certain assumptions were applied to the model to account for inputs with limited evidence.

CONCLUSIONS

The estimated budget impact of including capmatinib for mNSCLC with a METex14 skipping mutation is minimal, and the increased drug costs were partially offset by savings in AEs, and progression-related and terminal care costs.

Acquired MET D1228N Mutations Mediate Crizotinib Resistance in Lung Adenocarcinoma with ROS1 Fusion: A Case Report

Patients with non-small cell lung cancer (NSCLC) containing ROS1 fusions can have a marked response to the ROS1-targeted tyrosine kinase inhibitors (TKIs), such as crizotinib. Common resistance mechanisms of ROS1-fusion targeted therapy are acquired mutations in ROS1. Along with the use of next-generation sequencing in the clinical management of patients with NSCLC during sequential targeted therapy, many mechanisms of acquired resistance have been discovered in patients with activated tyrosine kinase receptors. Besides acquired resistance mutations, bypass mechanisms of resistance to epidermal growth factor receptor (EGFR)-TKI treatment are common in patients with EGFR mutations. Here we describe a patient with metastatic lung adenocarcinoma with CD74-ROS1 fusion who initially responded to crizotinib and then developed resistance by the acquired mutation of D1228N in the MET kinase domain, which showed short-term disease control for cabozantinib. KEY POINTS: The D1228N point mutation of MET is an acquired mutation for crizotinib resistance. The patient obtained short-term clinical benefit from cabozantinib therapy after resistance to crizotinib. The clinical use of next-generation sequencing could maximize the benefits of precision medicine in patients with cancer.

MET somatic activating mutations are responsible for lymphovenous malformation and can be identified using cell-free DNA next generation sequencing liquid biopsy

OBJECTIVE

Germline mutations of either the endothelial cell-specific tyrosine kinase receptor TIE2 or the glomulin (GLMN) gene are responsible for rare inherited venous malformations. Both genes affect the hepatocyte growth factor receptor c-Met, inducing vascular smooth muscle cell migration. Germline mutations of hepatocyte growth factor are responsible for lymphatic malformations, leading to lymphedema. The molecular alteration leading to the abnormal mixed vascular anomaly defined as lymphovenous malformation has remained unknown.

METHODS

A group of 4 patients with lymphovenous malformations were selected. Plasma was obtained from both peripheral and efferent vein samples at the vascular malformation site for cell-free DNA extraction. When possible, we analyzed tissue biopsy samples from the vascular lesion.

RESULTS

We have demonstrated that in all four patients, an activating MET mutation was present. In three of the four patients, the same pathogenic activating mutation, T1010I, was identified. The mutation was found at the tissue level for the patient with tissue samples available, confirming its causative role in the lymphovenous malformations.

CONCLUSIONS

In the present study, we have demonstrated that cell-free DNA next generation sequencing liquid biopsy is able to identify the MET mutations in affected tissues. Although a wider cohort of patients is necessary to confirm its causative role in lymphovenous malformations, these data suggest that lymphovenous malformations could result from postzygotic somatic mutations in genes that are key regulators of lymphatic development. The noninvasiveness of the method avoids any risk of bleeding and can be easily performed in children. We are confident that the present pioneering results have provided a viable alternative in the future for lymphovenous malformation diagnosis, allowing for subsequent therapy tailored to the genetic defect.

Crizotinib inhibits activation of MET pathway caused by MET extracellular SEMA domain duplication

OBJECTIVE

Aberrant MET activation, which promotes cell proliferation and tumor metastasis, occurs in many types of cancer and results from multiple mechanisms. A novel MET duplication mutation was found in a non-small cell lung cancer (NSCLC) patient. The clinical response to crizotinib was investigated and the functional relevance was characterized in cellular models.

MATERIALS AND METHODS

Next-generation sequencing (NGS) was performed on the tumor tissue and circulating tumor DNA (ctDNA) of a patient with advanced NSCLC. In vitro studies including western blot, proliferation assays and colony formation assays were used to confirm the clinical observations.

RESULTS

The patient was identified to harbor a duplication of the MET SEMA domain. After a month of treatment, the patient showed a marked response to crizotinib, a multikinase inhibitor with potent activity against MET. Functional in vitro studies demonstrated that expression of MET SEMA duplication in NIH-3T3 cells stimulated the activation of MET signaling. Crizotinib treatment obviously repressed cell proliferation, colony formation, and MET signaling pathway.

CONCLUSION

Crizotinib treatment resulted in a clinical response in a patient with MET SEMA duplication. Results of cellular analyses together with the clinical data suggest that this novel alteration may represent an actionable target in NSCLC patients.

Molecular correlates of response to capmatinib in advanced non-small-cell lung cancer: clinical and biomarker results from a phase I trial

BACKGROUND

Dysregulation of receptor tyrosine kinase MET by various mechanisms occurs in 3%-4% of non-small-cell lung cancer (NSCLC) and is associated with unfavorable prognosis. While MET is a validated drug target in lung cancer, the best biomarker strategy for the enrichment of a susceptible patient population still remains to be defined. Towards this end we analyze here primary data from a phase I dose expansion study of the MET inhibitor capmatinib in patients with advanced MET-dysregulated NSCLC.

PATIENTS AND METHODS

Eligible patients [≥18 years; Eastern Cooperative Oncology Group (ECOG) performance status ≤2] with MET-dysregulated advanced NSCLC, defined as either (i) MET status by immunohistochemistry (MET IHC) 2+ or 3+ or H-score ≥150, or MET/centromere ratio ≥2.0 or gene copy number (GCN) ≥5, or (ii) epidermal growth factor receptor wild-type (EGFRwt) and centrally assessed MET IHC 3+, received capmatinib at the recommended dose of 400 mg (tablets) or 600 mg (capsules) b.i.d. The primary objective was to determine safety and tolerability; the key secondary objective was to explore antitumor activity. The exploratory end point was the correlation of clinical activity with different biomarker formats.

RESULTS

Of 55 patients with advanced MET-dysregulated NSCLC, 40/55 (73%) had received two or more prior systemic therapies. All patients discontinued treatment, primarily due to disease progression (69.1%). The median treatment duration was 10.4 weeks. The overall response rate per RECIST was 20% (95% confidence interval, 10.4-33.0). In patients with MET GCN ≥6 (n = 15), the overall response rate by both the investigator and central assessments was 47%. The median progression-free survival per investigator for patients with MET GCN ≥6 was 9.3 months (95% confidence interval, 3.8-11.9). Tumor responses were observed in all four patients with METex14. The most common toxicities were nausea (42%), peripheral edema (33%), and vomiting (31%).

CONCLUSIONS

MET GCN ≥6 and/or METex14 are suited to predict clinical activity of capmatinib in patients with NSCLC (NCT01324479).

MET Expression in Advanced Non-Small-Cell Lung Cancer: Effect on Clinical Outcomes of Chemotherapy, Targeted Therapy, and Immunotherapy

BACKGROUND

The receptor tyrosine kinase MET is implicated in malignant transformation, tumor progression, metastasis, and acquired treatment resistance. We conducted an analysis of the effect of MET expression and MET genomic aberrations on the outcome of patients with advanced or metastatic pulmonary adenocarcinomas prospectively enrolled in an institutional precision oncology program.

PATIENTS AND METHODS

Standardized immunohistochemistry (IHC) analyses of MET and markers of pathway activation were available in 384 patients, and next-generation sequencing-based MET hotspot mutation analyses were available from 892 patients. Clinical data were retrieved with a median follow-up from initial diagnosis of 37 months.

RESULTS

High MET expression, defined as MET IHC 3+ or MET H-Score in the upper quartile, was observed in 102 of 384 patients (26.6%). MET exon 14 mutations were only detected in 7 of 892 patients (0.78%). High MET expression correlated with activation markers of the mitogen-activated protein kinase (MAPK) and phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT) pathways only in cases without Kirsten rat sarcoma viral oncogene homolog (KRAS), epidermal growth factor receptor (EGFR), v-Raf murine sarcoma viral oncogene homolog B (BRAF), anaplastic lymphoma kinase (ALK) and proto-oncogene tyrosine-protein kinase ROS (ROS1) aberrations. There was no association of MET expression with outcome during chemotherapy. High MET expression negatively affected the outcome during EGFR-targeting therapy but was associated with more favorable results with programmed death 1/programmed death ligand 1 (PD-L1)-directed therapy, independent of smoking history, PD-L1 expression or KRAS mutation. Two patients with MET exon 14 mutation and high PD-L1 expression failed to respond to pembrolizumab.

CONCLUSION

MET expression affects the outcomes of targeted therapies in non-small-cell lung cancer, thus supporting the development of biomarker-informed combination strategies. The interaction of MET expression and MET mutation with immune checkpoint inhibitor therapy is novel and merits further investigation.

Cabozantinib inhibits tumor growth and metastasis of a patient-derived xenograft model of papillary renal cell carcinoma with MET mutation

MET plays an important role in the development and progression of papillary renal cell carcinoma (pRCC). Evaluation of efficacy of MET inhibitors against pRCC has been hampered by limited preclinical models depicting MET abnormalities. We established a new patient-derived xenograft (PDX) model of pRCC carrying an activating mutation of MET and tested the ability of cabozantinib, an inhibitor of receptor tyrosine kinases including MET, to inhibit tumor growth and metastasis. Precision-cut, thin tissue slices from a pRCC specimen obtained by nephrectomy were implanted under the renal capsule of RAG2^-/-γC^-/- mice to establish first generation TSG-RCC-030. Histologic and genetic fidelity and metastatic potential of this model were characterized by immunohistochemistry, direct DNA sequencing and quantitative polymerase chain reaction (qPCR). The effect of cabozantinib on tumor growth and metastasis was evaluated. Whether measurements of circulating tumor DNA (ctDNA) by allele-specific qPCR could be used as a biomarker of tumor growth and response to therapy was determined. Subrenal and subcutaneous tumor grafts showed high take rates and metastasized to the lung. Both primary tumors and metastases expressed typical markers of pRCC and carried the same activating MET mutation as the parental tumor. Cabozantinib treatment caused striking tumor regression and inhibited lung metastasis in TSG-RCC-030. Plasma ctDNA levels correlated with tumor volume in control mice and changed in response to cabozantinib treatment. TSG-RCC-030 provides a realistic preclinical model to better understand the development and progression of pRCC with MET mutation and accelerate the development of new therapies for pRCC.

MET abnormalities in patients with genitourinary malignancies and outcomes with c-MET inhibitors

BACKGROUND

The purpose of this study was to determine the prevalence of MET amplification and mutation among GU malignancies and its association with clinical factors and responses to c-MET inhibitors.

PATIENTS AND METHODS

Patients with GU malignancies referred to our Phase I Clinical Trials Program were evaluated for MET mutation and amplification and outcomes using protocols with c-MET inhibitors.

RESULTS

MET amplification was found in 7 of 97 (7.2%) patients (4/27 renal [all clear cell], 1/18 urothelial, and 2/12 adrenocortical carcinoma), with MET mutation/variant in 3 of 54 (5.6%) (2/20 renal cell carcinoma [RCC] [1 clear cell and 1 papillary] and 1/16 prostate cancer). No demographic characteristics were associated with specific MET abnormalities, but patients who tested positive for mutation or amplification had more metastatic sites (median, 4 vs. 3 for wild type MET). Median overall survival after phase I consultation was 6.1 and 11.5 months for patients with and without a MET alteration, respectively (hazard ratio, 2.8; 95% confidence interval, 1.1 to 6.9; P = .034). Twenty-nine (25%) patients were treated according to a c-MET inhibitor protocol. Six (21%) had a partial response (prostate and RCC) and 10 (34%) had stable disease as best response. Median time to tumor progression was 2.3 months (range, 0.4-19.7) for all treated patients with no responses in patients with a MET abnormality or single-agent c-MET inhibitor treatment.

CONCLUSION

MET genetic abnormalities occur in diverse GU malignancies and are associated with a worse prognosis in a phase I setting. Efficacy of c-MET inhibitors was more pronounced in patients without MET abnormalities and when combined with other targets/drugs.

Analysis of MET genetic aberrations in patients with breast cancer at MD Anderson Phase I unit

BACKGROUND

c-MET is a receptor tyrosine kinase whose phosphorylation activates important proliferation pathways. MET amplification and mutation have been described in various malignancies, including breast cancer (BC), and c-MET overexpression is associated with worse survival outcomes in patients with BC. We describe MET mutation and amplification rates in a BC cohort of patients referred to a Phase I Unit.

METHODS

We reviewed the electronic medical records of all patients with advanced BC tested for MET amplification, mutation, or both who were referred to the Department of Investigational Cancer Therapeutics at MD Anderson.

RESULTS

A total of 107 patients with advanced BC were analyzed for MET mutation/variant (88 patients) or amplification (63 patients). Of these, 49 were tested for both genetic abnormalities. Three of 63 patients (4.7%) demonstrated MET gene amplification by fluorescence in situ hybridization (2 in primary tissue; 1 in metastatic site). MET mutation/variant was detected in 8 of 88 patients (9%). High-grade tumors were characteristic of all patients harboring MET amplification and were present in 7 of 8 (87.5%) of those with MET mutation. Metastatic sites were greater in MET-amplified compared with wild-type patients (median of 7 vs. 3 sites). Five of 8 patients (62.5%) with MET mutations had triple negative BC compared with 46% in controls. In addition, patients with positive test results for MET aberrations (n = 11) had inferior overall survival (OS) from Phase I consult compared with wild-type patients (n = 37), although this was not statistically significant (median OS = 9 vs. 15 months, P = .43).

CONCLUSIONS

In this cohort of patients with BC who were referred to our Phase I Department, MET aberrations were associated with higher metastatic burden and high-grade histology. We could not demonstrate differences in survival outcomes because of a small sample size.