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.

     

Emergence of Preexisting MET Y1230C Mutation as a Resistance Mechanism to Crizotinib in NSCLC with MET Exon 14 Skipping

IntroductionMET proto-oncogene, receptor tyrosine kinase gene exon 14 skipping (METex14) alterations represent a unique subset of oncogenic drivers in NSCLC. Preliminary clinical activity of crizotinib against METex14-positive NSCLC has been reported. The full spectrum of resistance mechanisms to crizotinib in METex14-positive NSCLC remains to be identified.MethodsHybrid capture–based comprehensive genomic profiling performed on a tumor specimen obtained at diagnosis, and a hybrid capture–based assay of circulating tumor DNA (ctDNA) at the time of progression during crizotinib treatment was assessed in a pairwise fashion.ResultsA METex14 alteration (D1010H) was detected in the pretreatment tumor biopsy specimen, as was MET proto-oncogene, receptor tyrosine kinase (MET) Y1230C, retrospectively, at very low frequency (0.3%). After a confirmed response during crizotinib treatment for 13 months followed by progression, both MET proto-oncogene, receptor tyrosine kinase gene Y1230C and D1010H were detected prospectively in the ctDNA.ConclusionEmergence of the preexisting MET Y1230C likely confers resistance to crizotinib in this case of METex14-positive NSCLC. Existence of pretreatment MET Y1230C may eventually modulate the response of METex14-positive NSCLC to type I MET tyrosine kinase inhibitors. Noninvasive plasma-based ctDNA assays can provide a convenient method to detect resistance mutations in patients with previously known driver mutations.     

Identification of a Novel EHBP1-MET Fusion in an Intrahepatic Cholangiocarcinoma Responding to Crizotinib

As an aggressive tumor, intrahepatic cholangiocarcinoma (ICC) originates in the epithelium of the bile duct and has a poor prognosis. The therapeutic options for ICC are challenging and limited because of poor response to chemotherapy and the lack of targeted therapy. Here we report on a 41‐year‐old female patient with ICC with EHBP1‐MET fusion and multiple intrahepatic metastases responding to crizotinib. Next‐generation sequencing–based tumor mutation profiling was performed on the tumor biopsy and circulating tumor DNA from plasma. A novel EHBP1‐MET fusion was identified and confirmed by Sanger sequencing. Immunohistochemistry of biopsy sample also revealed c‐MET positivity. Subsequently, the patient started treatment with MET inhibitor crizotinib. Magnetic resonance imaging scan demonstrated a partial response for 8 months. To the best of our knowledge, this is the first clinical case report of a patient with MET‐rearranged ICC successfully treated with crizotinib. This case suggests that crizotinib may be a promising treatment option for patients with ICC with MET fusion, warranting further clinical investigation.Key Points

• To the authors'' knowledge, this is the first reported case of EHBP1‐MET fusion.
• This is also the first clinical case report of clinical benefit from crizotinib treatment in an intrahepatic cholangiocarcinoma (ICC) with MET fusion.
• MET fusion is rare in ICC, and inhibition of MET could be a viable option for ICC that warrants further clinical investigation.

     

Safety of MET Tyrosine Kinase Inhibitors in Patients With MET Exon 14 Skipping Non-small Cell Lung Cancer: A Clinical Review

MET exon 14 (METex14) skipping mutations occur in 3% to 4% of non-small cell lung cancer (NSCLC) cases. Currently, four oral MET tyrosine kinase inhibitors (TKIs) are in use for the treatment of patients with METex14 skipping NSCLC (tepotinib, capmatinib, savolitinib, and crizotinib). To support optimal management of METex14 skipping NSCLC in this typically older patient population, the safety profiles of these treatment options are reviewed here. Published safety data from prospective clinical trials with MET TKIs in patients with METex14 skipping NSCLC were reviewed. Treatment-related adverse events (TRAEs) occurring in ≥ 10% of patients were reported where feasible. Guidance on clinical monitoring and management of key MET TKI TRAEs and drug-drug interactions is provided. Across the clinical trials, safety data for MET TKIs were reported for 442 patients with METex14 skipping. Peripheral edema was the most reported TRAE (50%-63% of patients; grade ≥ 3: 1%-11%), followed by nausea (26%-46% of patients; grade ≥ 3: 0%-1%). TRAEs led to dose reductions in 33% to 38% of patients and to discontinuation in 7% to 14% of patients, across the MET TKIs. Considerations on interpreting available safety data are provided, along with insights into monitoring and managing specific MET TKI TRAEs of interest and drug-drug interactions. Overall, MET TKIs are tolerable treatment options for patients with METex14 skipping NSCLC, an older population for whom chemo- or immuno-therapy may not be an effective nor tolerable option. More data regarding the effectiveness of safety interventions and management strategies are needed.     

The emerging role of MET/HGF inhibitors in oncology

The N-methyl-N′-nitroso-guanidine human osteosarcoma transforming gene (MET) receptor tyrosine kinase and its ligand hepatocyte growth factor (HGF) control cellular signaling cascades that direct cell growth, proliferation, survival, and motility. Aberrant MET/HGF activation has been observed in many tumor types, can occur by multiple mechanisms, and promotes cellular proliferation and metastasis via growth factor receptors and other oncogenic receptor pathways. Thus, MET/HGF inhibition has emerged as targeted anticancer therapies. Preclinically, neoplastic and metastatic phenotypes of several tumor cells, including non-small cell lung cancer, hepatocellular carcinoma, and gastric cancer, were abrogated by MET inhibition. Ongoing clinical development with tivantinib, cabozantinib, onartuzumab, crizotinib, rilotumumab, and ficlatuzumab has shown encouraging results. These trials have established a key role for MET in a variety of tumor types. Evidence is emerging for identification of aberrant MET activity biomarkers and selection of patient subpopulations that may benefit from targeted MET and HGF inhibitor treatment.     

Sensitivity and Resistance of MET Exon 14 Mutations in Lung Cancer to Eight MET Tyrosine Kinase Inhibitors In Vitro

BackgroundMNNG HOS transforming gene (MET) exon 14 mutations in lung cancer, including exon 14 skipping and point mutations, have been attracting the attention of thoracic oncologists as new therapeutic targets. Tumors with these mutations almost always acquire resistance, which also occurs in other oncogene-addicted lung cancers. However, the resistance mechanisms and treatment strategies are not fully understood.MethodsWe generated Ba/F3 cells expressing MET exon 14 mutations by retroviral gene transfer. The sensitivities of these cells to eight MET-tyrosine kinase inhibitors (TKIs) were determined using a colorimetric assay. In addition, using N-ethyl-N-nitrosourea mutagenesis, we generated resistant clones, searched for secondary MET mutations, and then examined the sensitivities of these resistant cells to different TKIs.ResultsBa/F3 cells transfected with MET mutations grew in the absence of interleukin-3, indicating their oncogenic activity. These cells were sensitive to all MET-TKIs except tivantinib. We identified a variety of secondary mutations. D1228 and Y1230 were common sites for resistance mutations for type I TKIs, which bind the active form of MET, whereas L1195 and F1200 were common sites for type II TKIs, which bind the inactive form. In general, resistance mutations against type I were sensitive to type II, and vice versa.ConclusionsMET-TKIs inhibited the growth of cells with MET exon 14 mutations. We also identified mutation sites specific for TKI types as resistance mechanisms and complementary activities between type I and type II inhibitors against those mutations. These finding should provide relevant clinical implication for treating patients with lung cancer harboring MET exon 14 mutations.     

A Phase 2 Study of Capmatinib in Patients With MET-Altered Lung Cancer Previously Treated With a MET Inhibitor

IntroductionCapmatinib is approved for MET exon 14–altered NSCLC on the basis of activity in targeted therapy–naive patients. We conducted a phase 2 study to assess the efficacy of capmatinib in patients previously treated with a MET inhibitor.MethodsPatients with advanced NSCLC harboring MET amplification or MET exon 14 skipping alterations received capmatinib 400 mg twice daily. The primary end point was the objective response rate. Secondary end points included progression-free survival, disease control rate (DCR), intracranial response rate, and overall survival. Circulating tumor DNA was analyzed to identify capmatinib resistance mechanisms.ResultsA total of 20 patients were enrolled between May 2016 and November 2019, including 15 patients with MET skipping alterations and five patients with MET amplification. All patients had received crizotinib; three had also received other MET-directed therapies. The median interval between crizotinib and capmatinib was 22 days (range: 4–374). Two patients (10%) achieved an objective response to capmatinib and 14 had stable disease, yielding a DCR of 80%. Among five patients who discontinued crizotinib for intolerance, the DCR was 83%, including two patients with the best tumor shrinkage of −25% and −28%. Intracranial DCR among four patients with measurable brain metastases was 100%, with no observed intracranial objective responses. Overall, the median progression-free survival and overall survival were 5.5 (95% confidence interval: 1.3–11.0) and 11.3 (95% confidence interval: 5.5–not reached) months, respectively. MET D1228 and Y1230 mutations and MAPK alterations were recurrently detected in postcrizotinib, precapmatinib plasma. New and persistent MET mutations and MAPK pathway alterations were detected in plasma at progression on capmatinib.ConclusionsCapmatinib has modest activity in crizotinib-pretreated MET-altered NSCLC, potentially owing to overlapping resistance mechanisms.     

Mechanistic Support for Combined MET and AR Blockade in Castration-Resistant Prostate Cancer

A recent phase III trial of the MET kinase inhibitor cabozantinib in men with castration-resistant prostate cancer (CRPC) failed to meet its primary survival end point; however, most men with CRPC have intact androgen receptor (AR) signaling. As previous work supports negative regulation of MET by AR signaling, we hypothesized that intact AR signaling may have limited the efficacy of cabozantinib in some of these patients. To assess the role of AR signaling on MET inhibition, we first performed an in silico analysis of human CRPC tissue samples stratified by AR signaling status (⁺ or ⁻), which identified MET expression as markedly increased in AR⁻ samples. In vitro, AR signaling inhibition in AR⁺ CRPC models increased MET expression and resulted in susceptibility to ligand (HGF) activation. Likewise, MET inhibition was only effective in blocking cancer phenotypes in cells with MET overexpression. Using multiple AR⁺ CRPC in vitro and in vivo models, we showed that combined cabozantinib and enzalutamide (AR antagonist) treatment was more efficacious than either inhibitor alone. These data provide a compelling rationale to combine AR and MET inhibition in CRPC and may explain the negative results of the phase III cabozantinib study in CRPC. Similarly, the expression of MET in AR⁻ disease, whether due to AR inhibition or loss of AR signaling, suggests potential utility for MET inhibition in select patients with AR therapy resistance and in AR⁻ prostate cancer.     

High MET Overexpression Does Not Predict the presence of MET exon 14 Splice Mutations in NSCLC: Results From the IFCT PREDICT.amm study

IntroductionMET proto-oncogene (MET) exon 14 splice site (METex14) mutations were recently described in NSCLC and has been reported to correlate with efficacy of MET tyrosine kinase inhibitors. High diversity of these alterations makes them hard to detect by DNA sequencing in clinical practice. Because METex14 mutations induce increased stabilization of the MET receptor, it is anticipated that these mutations are associated with MET overexpression. We aim to determine whether NSCLC with high MET overexpression could define a subset of patients with a high rate of METex14 mutations.MethodsFrom The French Cooperative Thoracic Intergroup PREDICT.amm cohort of 843 consecutive patients with a treatment-naive advanced NSCLC who were eligible for a first-line therapy, 108 NSCLC samples with high MET overexpression defined by an immunochemistry score 3+ were tested for METex14 mutations using fragment length analysis combined with optimized targeted next-generation sequencing. MET copy number analysis was also derived from the sequencing data.ResultsMETex14 mutations were detected in two patients (2.2%) who also displayed a TP53 mutation and a PIK3CA mutation, respectively. An MET gene copy number increase was observed in seven additional patients (7.7%). Next-generation sequencing analysis revealed inactivating mutations in TP53 (52.7%) and PTEN (1.1%), and oncogenic mutations in KRAS (28.6%), EGFR (7.7%), PIK3CA (4.4%), BRAF (4.4%), NRAS (2.2%), GNAS (1.1%), and IDH1 (1.1%).ConclusionsThe rate of METex14 mutations in NSCLC with high MET overexpression was similar to that found in unselected NSCLC. Moreover, we observed a high frequency of driver alterations in other oncogenes. Consequently these findings do not support the use of MET immunohistochemistry as a surrogate marker for METex14 mutations.     

De Novo MET Amplification in Chinese Patients With Non–Small-Cell Lung Cancer and Treatment Efficacy With Crizotinib: A Multicenter Retrospective Study

BackgroundDe novo mesenchymal–epithelial transition (MET) amplification represents an uncommon oncogenic event in patients with non–small-cell lung cancer, and little is known about the clinicopathologic characteristics, treatment, and prognosis of these patients.Patients and MethodsPatient data were retrospectively collected in 5 hospitals in China from 2014 to 2016. All MET amplification was identified with fluorescence in-situ hybridization. A MET/centromere ratio (MET/CEN) of ≥ 1.8 was defined as positive for MET amplification.ResultsAmplification of the de novo MET gene was identified in 47 patients with lung cancer. Thirty-two patients had a MET/CEN > 5, while 12 patients had intermediate-level amplification and only 3 had low-level amplification. Nine of 40 patients with advanced stage disease had brain metastases, and 15 had a solid predominant subtype of adenocarcinoma. Fifteen patients were treated with crizotinib. Of these, 11 patients (73.3%) had a partial response, 3 (20%) stable disease, and 1 (6.7%) progressive disease. The median progression-free survival of the 15 patients treated with crizotinib was 6.5 months (95% confidence interval, 2.7–10.3). Notably, treatment efficacy was more pronounced in patients with high-level MET amplification than in those with intermediate-level amplification (8.6 vs. 4.4 months, P = .008). The overall survival of patients with and without crizotinib treatment was 31.0 and 13.7 months, respectively (P = .001).ConclusionWe observed a trend toward a high prevalence of the solid predominant subtype of adenocarcinoma and of brain metastases in this group of patients. Patients with de novo MET amplification benefit from crizotinib treatment, especially those with high-level amplification.     

Distinct MET Protein Localization Associated With MET Exon 14 Mutation Types in Patients With Non–small-cell Lung Cancer

Background

The MET gene has been recognized as a potential important therapeutic target in non–small-cell lung cancer (NSCLC). We sought to investigate the MET exon 14 mutations in a cohort of Chinese patients with NSCLC.

Intra-tumor and Inter-tumor Heterogeneity in MET Exon 14 Skipping Mutations and Co-mutations in Pulmonary Pleomorphic Carcinomas

BackgroundMET exon 14 skipping mutation is a driver mutation in lung cancer and is highly enriched in pulmonary pleomorphic carcinomas (PPCs). Whether there is intratumor or intertumor heterogeneity in MET exon 14 skipping status or in co-occurring genetic alterations in lung cancers driven by MET exon 14 skipping is unknown.MethodsWe analyzed tumor specimens obtained from 23 PPC patients (10 autopsied and 13 surgically resected). MET exon 14 skipping was detected by RT-PCR. For patients with MET exon 14 skipping mutation, further analyses were performed. Genomic DNA (gDNA) was extracted from various histological components for each patient who underwent surgical resection (to assess intratumor heterogeneity). In autopsied patients, gDNA and total RNA were extracted from all metastatic lesions (to assess intertumor heterogeneity).ResultsMET exon 14 skipping mutation was detected in 4 patients (4/23, 17.4%): two surgically resected and two autopsied patients. We found no intratumor or intertumor heterogeneity in MET exon 14 skipping mutation status in these patients. We observed intratumor and intertumor heterogeneity in the copy number variations and/or mutational status of cancer-related genes; some of these differences may have an impact on MET tyrosine kinase inhibitor (TKI) efficacy.ConclusionIn our exploratory analysis of four cases, we observed that MET exon 14 skipping mutations are distributed homogeneously throughout histological components and between metastatic lesions. Our results also suggest that there is marked intertumor and intratumor heterogeneity in co-occurring genetic alterations, and therapeutic implications of such heterogeneity should be evaluated in future studies.     

MET Exon 14 Skipping in NSCLC: A Systematic Literature Review of Epidemiology,Clinical Characteristics,and Outcomes

IntroductionMET exon 14 (METex14) skipping is a rare oncogenic driver in non–small-cell lung cancer (NSCLC) for which targeted therapy with MET tyrosine kinase inhibitors (TKIs) was recently approved. Given the heterogeneity in published data of METex14 skipping NSCLC, we conducted a systematic literature review to evaluate its frequency, patient characteristics, and outcomes.MethodsOn June 13, 2022 we conducted a systematic literature review of publications and conference abstracts reporting frequency, patient characteristics, or outcomes of patients with METex14 skipping NSCLC.ResultsWe included 139 studies reporting frequency or patient characteristics (350,997 patients), and 39 studies reporting clinical outcomes (3989 patients). Median METex14 skipping frequency was 2.0% in unselected patients with NSCLC, with minimal geographic variation. Median frequency was 2.4% in adenocarcinoma or nonsquamous subgroups, 12.0% in sarcomatoid, and 1.3% in squamous histology. Patients with METex14 skipping NSCLC were more likely to be elderly, have adenocarcinoma histology; there was no marked sex or smoking status distribution. In first line of treatment, median objective response rate ranged from 50.7% to 68.8% with targeted therapies (both values correspond to MET TKIs), was 33.3% with immunotherapy, and ranged from 23.1% to 27.0% with chemotherapy.ConclusionsPatients with METex14 skipping are more likely to have certain characteristics, but no patient subgroup can be ruled out; thus, it is crucial to test all patients with NSCLC to identify suitable candidates for MET inhibitor therapy. MET TKIs appeared to result in higher efficacy outcomes, although no direct comparison with chemotherapy or immunotherapy regimens was found.     

Potent antitumor activity of cabozantinib,a c‐MET and VEGFR2 inhibitor,in a colorectal cancer patient‐derived tumor explant model

Antiangiogenic therapy is commonly used for the treatment of colorectal cancer (CRC). Although patients derive some clinical benefit, treatment resistance inevitably occurs. The MET signaling pathway has been proposed to be a major contributor of resistance to antiangiogenic therapy. MET is upregulated in response to vascular endothelial growth factor pathway inhibition and plays an essential role in tumorigenesis and progression of tumors. In this study, we set out to determine the efficacy of cabozantinib in a preclinical CRC patient‐derived tumor xenograft model. We demonstrate potent inhibitory effects on tumor growth in 80% of tumors treated. The greatest antitumor effects were observed in tumors that possess a mutation in the PIK3CA gene. The underlying antitumor mechanisms of cabozantinib consisted of inhibition of angiogenesis and Akt activation and significantly decreased expression of genes involved in the PI3K pathway. These findings support further evaluation of cabozantinib in patients with CRC. PIK3CA mutation as a predictive biomarker of sensitivity is intriguing and warrants further elucidation. A clinical trial of cabozantinib in refractory metastatic CRC is being activated.     

MET IHC Is a Poor Screen for MET Amplification or MET Exon 14 Mutations in Lung Adenocarcinomas: Data from a Tri-Institutional Cohort of the Lung Cancer Mutation Consortium

IntroductionMNNG HOS Transforming gene (MET) amplification and MET exon 14 (METex14) alterations in lung cancers affect sensitivity to MET proto-oncogene, receptor tyrosine kinase (MET [also known by the alias hepatocyte growth factor receptor]) inhibitors. Fluorescence in situ hybridization (FISH), next-generation sequencing (NGS), and immunohistochemistry (IHC) have been used to evaluate MET dependency. Here, we have determined the association of MET IHC with METex14 mutations and MET amplification.MethodsWe collected data on a tri-institutional cohort from the Lung Cancer Mutation Consortium. All patients had metastatic lung adenocarcinomas and no prior targeted therapies. MET IHC positivity was defined by an H-score of 200 or higher using SP44 antibody. MET amplification was defined by copy number fold change of 1.8x or more with use of NGS or a MET-to–centromere of chromosome 7 ratio greater than 2.2 with use of FISH.ResultsWe tested tissue from 181 patients for MET IHC, MET amplification, and METex14 mutations. Overall, 71 of 181 patients (39%) were MET IHC–positive, three of 181 (2%) were MET-amplified, and two of 181 (1%) harbored METex14 mutations. Of the MET-amplified cases, two were FISH positive with MET-to–centromere of chromosome 7 ratios of 3.1 and 3.3, one case was NGS positive with a fold change of 4.4x, and one of the three cases was MET IHC–positive. Of the 71 IHC-positive cases, one (1%) was MET-amplified and two (3%) were METex14-mutated. Of the MET IHC–negative cases, two of 110 (2%) were MET-amplified.ConclusionsIn this study, nearly all MET IHC–positive cases were negative for MET amplification or METex14 mutations. MET IHC can also miss patients with MET amplification. The limited number of MET-amplified cases in this cohort makes it challenging to demonstrate an association between MET IHC and MET amplification. Nevertheless, IHC appears to be an inefficient screen for these genomic changes. MET amplification or METex14 mutations can best be detected by FISH and a multiplex NGS panel.     

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.

Activity of Crizotinib (PF02341066), a Dual Mesenchymal-Epithelial Transition (MET) and Anaplastic Lymphoma Kinase (ALK) Inhibitor,in a Non-small Cell Lung Cancer Patient with De Novo MET Amplification

Crizotinib is a dual MET and ALK inhibitor. Currently, clinical development of crizotinib is focused primarily on ALK rearranged non-small cell lung cancer (NSCLC). Here we report an NSCLC patient with de novo MET amplification but no ALK rearrangement who achieved a rapid and durable response to crizotinib indicating is also a bona fide MET inhibitor.