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.

Refining patient selection of MET-activated non-small cell lung cancer through biomarker precision

Dysregulated MET signaling plays an important role in lung oncogenesis, tumor growth and invasiveness. It may occur through various mechanisms, such as MET overexpression or gene amplification or mutation, all of which can be detected by specific methods. The utility of MET overexpression as a biomarker remains unclear due to discrepancies in its occurrence and non-standardized cut-off thresholds. MET exon 14 skipping mutation (METex14) was established as a strong predictor of response to selective MET tyrosine kinase inhibitors (TKIs), and clinical trial results in patients with non-small cell lung cancer (NSCLC) harboring METex14 led to the approval of capmatinib and tepotinib by regulatory agencies worldwide. MET amplification is an emerging biomarker, with clinical data indicating an association between MET gene copy number and response to MET-TKIs. Additionally, MET amplification represents an important mechanism of resistance to TKIs in oncogene-driven NSCLC. The identification of molecular alterations for which targeted therapies are available is important, and high-throughput next-generation sequencing techniques can provide information on multiple genes at the same time, helping to provide valuable predictive information for oncogene-driven cancers. This review summarizes the current methods used for the detection of METex14, MET amplification and MET overexpression, and discusses the evidence for the use of MET-TKIs in patients with NSCLC with MET dysregulation. We discuss the practical challenges that impact the use of METex14 in the clinic and the evidence gaps that need to be addressed to validate additional genomic markers for MET-dependent cancers.

Managing Central Nervous System Spread of Lung Cancer: The State of the Art

Brain metastases (BrM) are common in both non-small-cell lung cancer and small-cell lung cancer. Substantial progress in BrM management has occurred in the past decade related to advances in both radiation and medical oncology. Recent and ongoing radiation trials have focused on increasing the candidacy for focal therapy of BrM with stereotactic radiosurgery; reducing the toxicity and improving patient selection for whole brain radiotherapy; and, in small-cell lung cancer, evaluating brain magnetic resonance imaging surveillance without prophylactic cranial irradiation, hippocampal avoidance in prophylactic cranial irradiation and whole brain radiotherapy, and the role of upfront stereotactic radiosurgery for BrM. In medical oncology, the development of multiple tyrosine kinase inhibitors with encouraging CNS activity and emerging data on the CNS activity of immune checkpoint inhibitors in some patients have opened the door to novel systemic and multidisciplinary treatment strategies for the management of BrM. Future research will focus on more robust characterizations of the CNS activity of targeted therapy and immunotherapies, as well as optimal integration and patient selection for multidisciplinary strategies involving CNS-active drugs, radiation therapy, and CNS surveillance.

A Need for More Molecular Profiling in Brain Metastases

As local disease control improves, the public health impact of brain metastases (BrM) continues to grow. Molecular features are frequently different between primary and metastatic tumors as a result of clonal evolution during neoplasm migration, selective pressures imposed by systemic treatments, and differences in the local microenvironment. However, biomarker information in BrM is not routinely obtained despite emerging evidence of its clinical value. We review evidence of discordance in clinically actionable biomarkers between primary tumors, extracranial metastases, and BrM. Although BrM biopsy/resection imposes clinical risks, these risks must be weighed against the potential benefits of assessing biomarkers in BrM. First, new treatment targets unique to a patient's BrM may be identified. Second, as BrM may occur late in a patient's disease course, resistance to initial targeted therapies and/or loss of previously identified biomarkers can occur by the time of occult BrM, rendering initial and other targeted therapies ineffective. Thus, current biomarker data can inform real-time treatment options. Third, biomarker information in BrM may provide useful prognostic information for patients. Appreciating the importance of biomarker analyses in BrM tissue, including how it may identify specific drivers of BrM, is critical for the development of more effective treatment strategies to improve outcomes for this growing patient population.

Targeting un-MET needs in advanced non-small cell lung cancer

Lung cancer classification has been radically transformed in recent years as genomic profiling has identified multiple novel therapeutic targets including MET exon 14 (METex14) alterations and MET amplification. Utilizing targeted therapies in patients with molecularly-defined NSCLC leads to remarkable objective response rates and improved progression-free survival. However, acquired resistance is inevitable. Several recent phase II trials have confirmed that METex14 NSCLC can be treated effectively with MET kinase inhibitors, such as crizotinib, capmatinib, tepotinib, and savolitinib. However, response rates for many MET TKIs are modest relative to the activity of targeted therapy in other oncogene-driven lung cancers, where ORRs are more consistently greater than 60%. In spite of significant gains in the field of MET inhibition in NSCLC, challenges remain: the landscape of resistance mechanisms to MET TKIs is not yet well characterized, and there may be intrinsic and acquired resistance mechanisms that require further characterization to enable increased MET TKI activity. In this review, we overview MET pathway dysregulation in lung cancer, methods of detection in the clinic, recent clinical trial data, and discuss current mechanisms of TKI resistance, exploring emerging strategies to overcome resistance.

Canadian Consensus Recommendations on the Management of MET-Altered NSCLC

In Canada, the therapeutic management of patients with advanced non-small cell lung cancer (NSCLC) with rare actionable mutations differs between provinces, territories, and individual centres based on access to molecular testing and funded treatments. These variations, together with the emergence of several novel mesenchymal-epithelial transition (MET) factor-targeted therapies for the treatment of NSCLC, warrant the development of evidence-based consensus recommendations for the use of these agents. A Canadian expert panel was convened to define key clinical questions, review evidence, discuss practice recommendations and reach consensus on the treatment of advanced MET-altered NSCLC. Questions addressed by the panel include: 1. How should the patients most likely to benefit from MET-targeted therapies be identified? 2. What are the preferred first-line and subsequent therapies for patients with MET exon 14 skipping mutations? 3. What are the preferred first-line and subsequent therapies for advanced NSCLC patients with de novo MET amplification? 4. What is the preferred therapy for patients with advanced epidermal growth factor receptor (EGFR)-mutated NSCLC with acquired MET amplification progressing on EGFR inhibitors? 5. What are the potential strategies for overcoming resistance to MET inhibitors? Answers to these questions, along with the consensus recommendations herein, will help streamline the management of MET-altered NSCLC in routine practice, assist clinicians in therapeutic decision-making, and help ensure optimal outcomes for NSCLC patients with MET alterations.

Targeted therapy in advanced non-small cell lung cancer: current advances and future trends

Lung cancer remains the leading cause of cancer-related mortality in both men and women in the US and worldwide. Non-small cell lung cancer is the most common variety accounting for 84% of the cases. For a subset of patients with actionable mutations, targeted therapy continues to provide durable responses. Advances in molecular and immunohistochemical techniques have made it possible to usher lung cancer into the era of personalized medicine, with the patient getting individualized treatment based on these markers. This review summarizes the recent advances in advanced NSCLC targeted therapy, focusing on first-in-human and early phase I/II clinical trials in patients with advanced disease. We have divided our discussion into different topics based on these agents' mechanisms of action. This article is aimed to be the most current review of available and upcoming targeted NSCLC treatment options. We will also summarize the currently available phase I/II clinical trial for NSCLC patients at the end of each section.