Prognosis and Concurrent Genomic Alterations in Patients With Advanced NSCLC Harboring MET Amplification or MET Exon 14 Skipping Mutation Treated With MET Inhibitor: A Retrospective Study

Non-small cell lung cancer with MET amplification: review of epidemiology, associated disease characteristics, testing procedures, burden, and treatments

Introduction

Mesenchymal-epidermal transition factor gene amplification (METamp) is being investigated as a therapeutic target in advanced non-small cell lung cancer (NSCLC). We reviewed the epidemiology and disease characteristics associated with primary and secondary METamp, as well as the testing procedures used to identify METamp, in advanced NSCLC. Economic and humanistic burdens, and the practice patterns and treatments under investigation for METamp were also examined.

Methods

Embase and Medline (via ProQuest), ClinicalTrials.gov, and Cochrane Controlled Register of Trials (2015-2022) were systematically searched. Conference abstracts were searched via Embase and conference proceedings websites (2020-2022). The review focused on evidence from the United States; global evidence was included for identified evidence gaps.

Results

The median rate of primary METamp in NSCLC across the references was 4.8% (n=4 studies) and of secondary METamp (epidermal growth factor receptor [EGFR]-mutant NSCLC) was 15% (n=10). Next-generation sequencing (NGS; n=12) and/or fluorescence in situ hybridization (FISH; n=11) were most frequently used in real-world studies and FISH testing most frequently used in clinical trials (n=9/10). METamp definitions varied among clinical trials using ISH/FISH testing (MET to chromosome 7 centromere ratio of ≥1.8 to ≥3.0; or gene copy number [GCN] ≥5 to ≥10) and among trials using NGS (tissue testing: GCN ≥6; liquid biopsy: MET copy number ≥2.1 to >5). Limited to no data were identified on the economic and humanistic burdens, and real-world treatment of METamp NSCLC. Promising preliminary results from trials enrolling patients with EGFR-mutated, METamp advanced NSCLC progressing on an EGFR-tyrosine kinase inhibitor (TKI) were observed with MET-TKIs (i.e., tepotinib, savolitinib, and capmatinib) in combination with EGFR-TKIs (i.e., gefitinib and osimertinib). For metastatic NSCLC and high-level METamp, monotherapy with capmatinib, crizotinib, and tepotinib are recommended in the 2022 published NSCLC NCCN Guidelines.

Conclusion

Primary METamp occurs in approximately 5% of NSCLC cases, and secondary METamp in approximately 15% of cases previously treated with an EGFR inhibitor. Variability in testing methods (including ISH/FISH and NGS) and definitions were observed. Several treatments are promising in treating METamp NSCLC. Additional studies evaluating the clinical, economic, and humanistic burdens are needed.

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

BACKGROUND

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.

OBJECTIVE

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.

CONCLUSION

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.

Targeting MET Amplification: Opportunities and Obstacles in Therapeutic Approaches

The MET gene plays a vital role in cellular proliferation, earning it recognition as a principal oncogene. Therapies that target MET amplification have demonstrated promising results both in preclinical models and in specific clinical cases. A significant obstacle to these therapies is the ability to distinguish between focal amplification and polysomy, a task for which simple MET copy number measurement proves insufficient. To effectively differentiate between the two, it is crucial to utilize comparative measures, including in situ hybridization (ISH) with the centromere or next generation sequencing (NGS) with adjacent genes. Despite the promising potential of MET amplification treatment, the judicious selection of patients is paramount to maximize therapeutic efficacy. The effectiveness of MET inhibitors can fluctuate depending on the extent of MET amplification. Future research must seek to establish the ideal threshold value for MET amplification, identify the most efficacious combination therapies, and innovate new targeted treatments for patients exhibiting MET amplification.

Consensus Recommendations for the Diagnosis, Biomarker Testing, and Clinical Management of Advanced or Metastatic Non-small Cell Lung Cancer With Mesenchymal-Epithelial Transition Exon 14 Skipping Mutations in the Middle East, Africa, and Russia

Mesenchymal-epithelial transition exon 14 (METex14) skipping mutations occur in about 3%-4% of patients with non-small cell lung cancer (NSCLC). This is an aggressive subtype associated with poor prognosis. METex14 skipping is a potentially targetable mutation. Targeted therapy is a promising treatment modality for patients with advanced/metastatic METex14-mutant NSCLC. Performing systematic molecular testing to detect the driver mutation is essential for initiating targeted therapy. However, there is a lack of guidelines on molecular testing for assessing the eligibility of patients for targeted therapy. Therefore, a multidisciplinary panel consisting of experts from the Middle East, Africa, and Russia convened via a virtual advisory board meeting to provide their insights on various molecular testing techniques for the diagnosis of METex14 skipping mutation, management of patients with targeted therapies, and developing consensus recommendations for improving the processes. The expert panel emphasized performing molecular testing and liquid biopsy before treatment initiation and tissue re-biopsy for patients with failed molecular testing. Liquid biopsy was recommended as complementary to tissue biopsy for disease monitoring and prognosis. Selective MET inhibitors were recommended as the first and subsequent lines of therapy. These consensus recommendations will facilitate the management of METex14 skipping NSCLC in routine practice and warrant optimum outcomes for these patients.

Savolitinib versus crizotinib for treating MET positive non-small cell lung cancer

BACKGROUND

The c-MET protein, encoded by the mesenchymal-epithelial transition factor (MET) gene, can regulate cell proliferation, migration and invasion. Studies have shown that it is one of the essential driver genes for non-small cell lung cancer (NSCLC). Currently, several clinical studies have carried out objective assessments on the efficacy and safety of different types of MET tyrosine kinase inhibitors (TKIs). However, direct cross-sectional comparisons between different agents are still not available.

METHODS

Our study was a single-center retrospective clinical study, which collected the data from MET positive NSCLC patients treated with MET TKIs at the Lung Cancer Center of Peking Union Medical College Hospital. We explored the efficacy and safety of crizotinib versus savolitinib in patients with METex14 skipping and MET amplification, separately.

RESULTS

Patients with METex14 skipping (median PFS = 10.7 months) had a better clinical response to MET TKIs than MET amplification patients (median PFS = 4.1 months). In the METex14 skipping subgroup, savolitinib did not show better survival benefit with significance than crizotinib (p > 0.05). In the MET amplification subgroup, savolitinib (median PFS = 7.1 months) demonstrated a better progression-free survival benefit than crizotinib (median PFS = 1.4 months), p = 0.05. The most common adverse effects of both MET TKIs were peripheral edema (41.2%), gastrointestinal reactions (23.5%), and liver injury (14.7%). The incidence rate of peripheral edema was higher in savolitinib than crizotinib.

CONCLUSION

In METex14 skipping NSCLC patients, the efficacy of savolitinib and crizotinib did not show significant difference. In MET amplification patients, savolitinib showed better efficacy than crizotinib.

Crizotinib efficacy and safety in patients with advanced NSCLC harboring MET alterations: A real-life data of Turkish Oncology Group

Crizotinib is a multikinase inhibitor, effective in non-small cell lung cancer (NSCLC) harboring mesenchymal-epidermal transition (MET) alterations. Although small prospective studies showed efficacy and safety of crizotinib in NSCLC with MET alterations, there is limited real-life data. Aim of this study is to investigate real-life efficacy and safety of crizotinib in patients with advanced NSCLC harboring MET alterations. This was a retrospective, multicenter (17 centers) study of Turkish Oncology Group. Patients' demographic, histological data, treatment, response rates, survival outcomes, and toxicity data were collected. Outcomes were presented for the study population and compared between MET alteration types. Total of 62 patients were included with a median age of 58.5 (range, 26-78). Major histological type was adenocarcinoma, and 3 patients (4.8%) had sarcomatoid component. The most common MET analyzing method was next generation sequencing (90.3%). MET amplification and mutation frequencies were 53.2% (n = 33) and 46.8% (n = 29), respectively. Overall response rate and disease control rate were 56.5% and 74.2% in whole study population, respectively. Median progression free survival (PFS) was 7.2 months (95% confidence interval [CI]: 3.8-10.5), and median overall survival (OS) was 18.7 months (95% CI: 13.7-23.7), regardless of treatment line. Median PFS was 6.1 months (95% CI: 5.6-6.4) for patients with MET amplification, whereas 14.3 months (95% CI: 6.7-21.7) for patients with MET mutation (P = .217). Median PFS was significantly longer in patients who have never smoked (P = .040), have good performance score (P < .001), and responded to the treatment (P < .001). OS was significantly longer in patients with MET mutation (25.6 months, 95% CI: 15.9-35.3) compared to the patients with MET amplification (11.0 months; 95% CI: 5.2-16.8) (P = .049). In never-smokers, median OS was longer than smoker patients (25.6 months [95% CI: 11.8-39.3] vs 16.5 months [95% CI: 9.3-23.6]; P = .049). The most common adverse effects were fatigue (50%), peripheral edema (21%), nausea (29%) and diarrhea (19.4%). Grade 3 or 4 adverse effects were observed in 6.5% of the patients. This real-life data confirms efficacy and safety of crizotinib in the treatment of advanced NSCLC harboring MET alteration.