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

INTRODUCTION

MET 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.

METHODS

On 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.

RESULTS

We 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.

CONCLUSIONS

Patients 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.

The race to target MET exon 14 skipping alterations in non-small cell lung cancer: The Why, the How, the Who, the Unknown, and the Inevitable

A number of small molecule tyrosine kinase inhibitors (TKIs) have now been approved for the treatment of non-small cell lung cancers (NSCLC), including those targeted against epidermal growth factor receptor, anaplastic lymphoma kinase, and ROS1. Despite a wealth of agents developed to target the receptor tyrosine kinase, MET, clinical outcomes have as yet been disappointing, leading to pessimism about the role of MET in the pathogenesis of NSCLC. However, in recent years, there has been a renewed interest in MET exon 14 alterations as potential drivers of lung cancer. MET exon 14 alterations, which result in increased MET protein levels due to disrupted ubiquitin-mediated degradation, occur at a prevalence of around 3% in adenocarcinomas and around 2% in other lung neoplasms, making them attractive targets for the treatment of lung cancer. At least five MET-targeted TKIs, including crizotinib, cabozantinib, capmatinib, tepotinib, and glesatinib, are being investigated clinically for patients with MET exon 14 altered-NSCLC. A further two compounds have shown activity in preclinical models. In this article, we review the current clinical and preclinical data available for these TKIs, along with a number of other potential therapeutic options, including antibodies and immunotherapy. A number of questions remain unanswered regarding the future of MET TKIs, but unfortunately, the development of resistance to targeted therapies is inevitable. Resistance is expected to arise as a result of receptor tyrosine kinase mutation or from upregulation of MET ligand expression; potential strategies to overcome resistance are proposed.