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.     

Asian Thoracic Oncology Research Group (ATORG) Expert Consensus Statement on MET Alterations in NSCLC: Diagnostic and Therapeutic Considerations

Non-small cell lung cancer (NSCLC) is a heterogeneous disease, with many oncogenic driver mutations, including de novo mutations in the Mesenchymal Epithelial Transition (MET) gene (specifically in Exon 14 [ex14]), that lead to tumourigenesis. Acquired alterations in the MET gene, specifically MET amplification is also associated with the development of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) resistance in patients with EGFR-mutant NSCLC. Although MET has become an actionable biomarker with the availability of MET-specific inhibitors in selected countries, there is differential accessibility to diagnostic platforms and targeted therapies across countries in Asia-Pacific (APAC).The Asian Thoracic Oncology Research Group (ATORG), an interdisciplinary group of experts from Australia, Hong Kong, Japan, Korea, Mainland China, Malaysia, the Philippines, Singapore, Taiwan, Thailand and Vietnam, discussed testing for MET alterations and considerations for using MET-specific inhibitors at a consensus meeting in January 2022, and in subsequent offline consultation.Consensus recommendations are provided by the ATORG group to address the unmet need for standardised approaches to diagnosing MET alterations in NSCLC and for using these therapies. MET inhibitors may be considered for first-line or second or subsequent lines of treatment for patients with advanced and metastatic NSCLC harbouring MET ex14 skipping mutations; MET ex14 testing is preferred within multi-gene panels for detecting targetable driver mutations in NSCLC. For patients with EGFR-mutant NSCLC and MET amplification leading to EGFR TKI resistance, enrolment in combination trials of EGFR TKIs and MET inhibitors is encouraged.     

Alterations in the PI3K Pathway Drive Resistance to MET Inhibitors in NSCLC Harboring MET Exon 14 Skipping Mutations

Hepatocyte growth factor receptor (MET) tyrosine kinase inhibitors (MET TKIs) have been found to have efficacy against advanced NSCLC with mutations causing MET exon 14 skipping (METex14 mutations), but primary resistance seems frequent, as response rates are lower than those for targeted TKIs of other oncogene-addicted NSCLCs. Given the known interplay between MET and phosphoinositide 3-kinases (PI3K), we hypothesized that in METex14 NSCLC, PI3K pathway alterations might contribute to primary resistance to MET TKIs. We reviewed clinical data from 65 patients with METex14 NSCLC, assessing PI3K pathway alterations by targeted next-generation sequencing (mutations) and immunohistochemistry (loss of phosphatase and tensin homolog [PTEN]). Using a cell line derived from a patient with primary resistance to a MET TKI and cell lines harboring both a METex14 mutation and a PI3K pathway alteration, we assessed sensitivity to MET TKIs used alone or with a PI3K inhibitor and investigated relevant signaling pathways. We found a phosphatidylinositol 3-kinase catalytic subunit alpha (PIK3CA) mutation in two of 65 samples (3%) and loss of PTEN in six of 26 samples (23%). All three of the MET TKI–treated patients with a PI3K pathway alteration had been found to have progressive disease at first assessment. Likewise, MET TKIs had no effect on the proliferation of METex14-mutated cell lines with a PI3K pathway alteration, including the PTEN-lacking patient-derived cell line. Treatment combining a MET TKI with a PI3K inhibitor caused inhibition of both PI3K and MAPK signaling and restored sensitivity to MET TKIs. PI3K pathway alterations are common in METex14 NSCLC and may confer primary resistance to MET TKIs. In preclinical models, PI3K inhibition restores sensitivity to MET TKIs.     

Long-term experience with tepotinib in Japanese patients with MET exon 14 skipping NSCLC from the Phase II VISION study

Tepotinib is a highly selective MET tyrosine kinase inhibitor (TKI) that has demonstrated robust and durable clinical activity in patients with MET exon 14 (METex14) skipping non–small-cell lung cancer (NSCLC). In the Phase II VISION study, patients received oral tepotinib 500 mg once daily. The primary endpoint was an objective response by an independent review committee (IRC) according to RECIST v1.1 criteria. The secondary endpoints included duration of response (DOR), progression-free survival (PFS), overall survival (OS), and safety. Here we report the analysis of the efficacy and safety of tepotinib in all Japanese patients with advanced METex14 skipping NSCLC from VISION (n = 38) with >18 months' follow-up. The median age of the Japanese patients was 73 years (range 63–88), 39.5% of patients were ≥75 years old, 68.4% were male, 55.3% had a history of smoking, 76.3% had adenocarcinoma, and 10.5% of patients had known brain metastases at baseline. Overall, the objective response rate (ORR) was 60.5% (95% confidence interval (CI): 43.4, 76.0) with a median DOR of 18.5 months (95% CI: 8.3, not estimable). ORR in treatment-naïve patients (n = 18) was 77.8% (95% CI: 52.4, 93.6), and in patients aged ≥75 years (n = 15), ORR was 73.3% (95% CI: 44.9, 92.2). The most common treatment-related adverse event (AE) with any grade was blood creatinine increase (65.8%), which resolved following tepotinib discontinuation. Other common treatment-related AEs were peripheral edema (60.5%), hypoalbuminemia (34.2%), diarrhea (28.9%), and nausea (15.8%). In summary, tepotinib demonstrated robust and durable clinical activity irrespective of age or therapy line, with a manageable safety profile in Japanese patients with METex14 skipping NSCLC enrolled in VISION.     

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.     

Safety of Tepotinib in Patients With MET Exon 14 Skipping NSCLC and Recommendations for Management

IntroductionThe MET inhibitor tepotinib demonstrated durable clinical activity in patients with advanced MET exon 14 (METex14) skipping NSCLC. We report detailed analyses of adverse events of clinical interest (AECIs) in VISION, including edema, a class effect of MET inhibitors.Patients and MethodsIncidence, management, and time to first onset/resolution were analyzed for all-cause AECIs, according to composite categories (edema, hypoalbuminemia, creatinine increase, and ALT/AST increase) or individual preferred terms (pleural effusion, nausea, diarrhea, and vomiting), for patients with METex14 skipping NSCLC in the phase II VISION trial.ResultsOf 255 patients analyzed (median age: 72 years), edema, the most common AECI, was reported in 69.8% (grade 3, 9.4%; grade 4, 0%). Median time to first edema onset was 7.9 weeks (range: 0.1-58.3). Edema was manageable with supportive measures, dose reduction (18.8%), and/or treatment interruption (23.1%), and rarely prompted discontinuation (4.3%). Other AECIs were also manageable and predominantly mild/moderate: hypoalbuminemia, 23.9% (grade 3, 5.5%); pleural effusion, 13.3% (grade ≥ 3, 5.1%); creatinine increase, 25.9% (grade 3, 0.4%); nausea, 26.7% (grade 3, 0.8%), diarrhea, 26.3% (grade 3, 0.4%), vomiting 12.9% (grade 3, 1.2%), and ALT/AST increase, 12.2% (grade ≥ 3, 3.1%). GI AEs typically occurred early and resolved in the first weeks.ConclusionTepotinib was well tolerated in the largest trial of a MET inhibitor in METex14 skipping NSCLC. The most frequent AEs were largely mild/moderate and manageable with supportive measures and/or dose reduction/interruption, and caused few withdrawals in this elderly population.     

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.     

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.     

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 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.     

Capmatinib in Japanese patients with MET exon 14 skipping–mutated or MET-amplified advanced NSCLC: GEOMETRY mono-1 study

MET mutations leading to exon 14 skipping (METΔex14) are strong molecular drivers for non–small-cell lung cancer (NSCLC). Capmatinib is a highly potent, selective oral MET inhibitor that showed clinically meaningful efficacy and a manageable safety profile in a global phase II study (GEOMETRY mono-1, NCT02414139) in patients with advanced METΔex14-mutated/MET-amplified NSCLC. We report results of preplanned analyses of 45 Japanese patients according to MET status (METΔex14-mutated or MET-amplified) and line of therapy (first- [1L] or second-/third-line [2/3L]). The starting dose was 400 mg twice daily. The primary endpoint was the objective response rate (ORR) assessed by a blinded independent review committee. A key secondary endpoint was duration of response (DOR). Among METΔex14-mutated patients, in the 1L group, one patient achieved partial response (DOR of 4.24 months) and the other had stable disease. In the 2/3L group, the ORR was 36.4% (95% confidence interval [CI] 10.9%-69.2%), median DOR was not evaluable, and progression-free survival was 4.70 months. One patient (2/3L group) showed partial resolution of brain lesions per independent neuroradiologist review. In MET-amplified patients with a MET gene copy number of ≥10, the ORR was 100% (2/2 patients) in the 1L group and 45.5% (5/11 patients) in the 2/3L group, with DOR of 8.2 and 8.3 months, respectively. Common treatment-related adverse events among the 45 Japanese patients were blood creatinine increased (53.3%), nausea (35.6%), and oedema peripheral (31.1%); most were grade 1/2 severity. In conclusion, capmatinib was effective and well tolerated by Japanese patients with METΔex14/MET-amplified NSCLC, consistent with the overall population.     

The promise of selective MET inhibitors in non-small cell lung cancer with MET exon 14 skipping

Dysregulated activation of the MET tyrosine kinase receptor is implicated in the development of solid tumors and can arise through several mechanisms, including gene amplification, overexpression of the receptor and/or its ligand hepatocyte growth factor (HGF), and the acquisition of activating mutations. The most common activating mutations cause exon 14 to be skipped during MET mRNA splicing. This in-frame deletion, known as MET exon 14, results in production of a shortened receptor that lacks a juxtamembrane domain but retains affinity for HGF. However, the negative regulatory function located within this protein sequence is lost, leading to receptor accumulation on the cell surface and prolonged activation by HGF. MET mutations causing exon 14 skipping appear to be true oncogenic drivers and occur in patients and tumors with distinct characteristics.Increasing evidence suggests that tumors carrying such mutations are sensitive to MET inhibition, raising the hope that selective MET inhibitors will provide patients with optimal anticancer activity with minimal toxicity.We discuss the prospects for selective MET inhibitors in the treatment of non-small cell lung cancer harboring MET exon 14 skipping.     

MET alterations in NSCLC—Current Perspectives and Future Challenges

Targeted therapies have revolutionized the treatment and improved the outcome for oncogene-driven NSCLC and an increasing number of oncogenic driver therapies have become available. For MET-dysregulated NSCLC (especially MET exon 14 skipping mutations and MET-amplifications, which is one of the most common bypass mechanisms of resistance in oncogene-addicted NSCLC), several anti–MET-targeted therapies have been approved recently (MET exon 14 skipping mutation) and multiple others are in development. In this narrative review, we summarize the role of MET as an oncogenic driver in NSCLC, discuss the different testing methods for exon 14 skipping mutations, gene amplification, and protein overexpression, and review the existing data and ongoing clinical trials regarding targeted therapies in MET-altered NSCLC. As immunotherapy with or without chemotherapy has become the standard of care for advanced NSCLC, immunotherapy data for MET-dysregulated NSCLC are put into perspective. Finally, we discuss future challenges in this rapidly evolving landscape.     

DNA-Based versus RNA-Based Detection of MET Exon 14 Skipping Events in Lung Cancer

Introduction

Genomic variants that lead to MET proto-oncogenem receptor tyrosine kinase (MET) exon 14 skipping represent a potential targetable molecular abnormality in NSCLC. Consequently, reliable molecular diagnostic approaches that detect these variants are vital for patient care.

MET gene amplification or EGFR mutation activate MET in lung cancers untreated with EGFR tyrosine kinase inhibitors

We analyzed MET protein and copy number in NSCLC with or without EGFR mutations untreated with EGFR tyrosine kinase inhibitors (TKIs). MET copy number was examined in 28 NSCLC and 4 human bronchial epithelial cell lines (HBEC) and 100 primary tumors using quantitative real‐time PCR. Positive results were confirmed by array comparative genomic hybridization and fluorescence in‐situ hybridization. Total and phospho‐MET protein expression was determined in 24 NSCLC and 2 HBEC cell lines using Western blot. EGFR mutations were examined for exon 19 deletions, T790M, and L858R. Knockdown of EGFR with siRNA was performed to examine the relation between EGFR and MET activation. High‐level MET amplification was observed in 3 of 28 NSCLC cell lines and in 2 of 100 primary lung tumors that had not been treated with EGFR‐TKIs. MET protein was highly expressed and phosphorylated in all the 3 cell lines with high MET amplification. In contrast, 6 NSCLC cell lines showed phospho‐MET among 21 NSCLC cell lines without MET amplification (p = 0.042). Furthermore, those 6 cell lines harboring phospho‐MET expression without MET amplification were all EGFR mutant (p = 0.0039). siRNA‐mediated knockdown of EGFR abolished phospho‐MET expression in examined 3 EGFR mutant cell lines of which MET gene copy number was not amplified. By contrast, phospho‐MET expression in 2 cell lines with amplified MET gene was not down‐regulated by knockdown of EGFR. Our results indicated that MET amplification was present in untreated NSCLC and EGFR mutation or MET amplification activated MET protein in NSCLC. © 2008 Wiley‐Liss, Inc.     

Optimization of patient selection for EGFR-TKIs in advanced non-small cell lung cancer by combined analysis of KRAS, PIK3CA, MET, and non-sensitizing EGFR mutations

Background

We present a comprehensive analysis of KRAS, PIK3CA, MET, and non-sensitizing EGFR mutations in advanced non-small cell lung cancer (NSCLC) patients treated with tyrosine kinase inhibitors (TKIs), with the aim of clarifying the relative contribution of these molecular alterations to resistance.

Patients and methods

One hundred and sixty-six patients with advanced NSCLC treated with EGFR-TKIs with available archival tissue specimens were included. EGFR (exons 18–21), KRAS (exons 2, 3), PIK3CA (exons 9, 20), and MET (exons 14, 15) mutations were analyzed using PCR-based sequencing. Among all the mutations evaluated, only KRAS, PIK3CA, MET, and non-sensitizing EGFR mutations, defined as “TKI non-sensitizing mutations” were used for response, time to progression (TTP), and overall survival (OS) analysis.

Results

TKI non-sensitizing mutations were associated with disease progression (p?=?0.001), shorter TTP (p?p?=?0.03). Cox’s multivariate analysis including histology and performance status showed that TKI non-sensitizing mutations were independent factors for shorter TTP (p?p?=?0.01).

Conclusions

When KRAS, PIK3CA, MET, and non-sensitizing EGFR mutations are concomitant, up to 96.0% of NSCLC patients unlikely to respond to TKIs can be identified, and they represented independent negative prognostic factors. Comprehensive molecular dissection of EGFR signaling pathways should be considered to select advanced NSCLC patients for TKIs therapies.     

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.