Effective response to crizotinib of concurrent KIF5B-MET and MET-CDR2-rearranged non-small cell lung cancer: A case report

A novel HLA-DQB2::MET gene fusion variant in lung adenocarcinoma with prolonged response to tepotinib: a case report

Background

MET rearrangements are infrequently observed in non-small cell lung cancer (NSCLC). Advanced genomic detection techniques have unveiled such infrequent genomic variations, particularly MET fusions in approximately 0.5% of NSCLC patients. Tyrosine kinase inhibitors (TKIs) have revolutionized the standard of care in lung cancer and more recently a second generation MET TKI tepotinib received Food and Drug Administration (FDA) approval for MET exon 14 alterations in metastatic NSCLC. Despite this, the therapeutic landscape for MET-rearranged NSCLC patients remains significantly unexplored. The aim of our report is to detail a unique case of a patient with metastatic lung adenocarcinoma with a novel HLA-DQB2::MET fusion detected by next-generation sequencing (NGS) following previous treatment resistance.

Case Description

A 73-year-old female was initially started on carboplatin, pemetrexed and pembrolizumab with maintenance, but eventually had progression in the left upper lobe (LUL). Upon progression she was enrolled in a clinical trial of a monoclonal antibody with or without a PD-1 inhibitor, but brain metastasis progression was eventually detected by magnetic resonance imaging (MRI) requiring stereotactic radiosurgery (SRS) and a craniotomy. The trial drug was eventually discontinued due to progression and toxicity and NGS on bronchoscopy tissue revealed HLA-DQB2::MET fusion. The patient was initiated on tepotinib and continues with clinical and radiological stable disease for over 12 months. The patient's response to a MET inhibitor, tepotinib, underscores the potential efficacy of selective MET inhibitors for individuals with previously unexplored MET fusions.

Conclusions

The positive response to tepotinib of a patient with NSCLC harboring a novel MET-Fusion underscores the importance of the use of comprehensive next-generational sequencing-based panels and highlights the necessity for additional research and clinical exploration of selective MET inhibitors for managing NSCLC with MET rearrangements.

Case report: Acquired resistance to crizotinib from a MET Y1230H mutation in a patient with non-small cell lung cancer and KIF5B-MET fusion

Background

The c-met proto-oncogene (MET) serves as a significant primary oncogenic driver in non-small cell lung cancer (NSCLC) and has the potential to fuse with other genes, such as KIF5B, although it occurs infrequently. Only a limited number of reported cases have examined the clinical efficacy of crizotinib in patients with KIF5B-MET gene fusion, with no known data regarding acquired resistance to crizotinib and its potential mechanisms. In this report, we present the clinical progression of a female patient diagnosed with NSCLC and harboring a KIF5B-MET gene fusion.

Case description

The patient initially exhibited partial response to first-line crizotinib treatment, albeit for a short duration and with limited efficacy. Subsequent disease progression revealed the emergence of a secondary MET mutation, specifically MET Y1230H, leading to acquired resistance to crizotinib.

Conclusion

The reporting of this case is imperative for informing clinical practice, given the uncommon occurrence of NSCLC with MET fusion, displaying responsiveness to MET tyrosine kinase inhibitor therapy, as well as the emergence of the secondary Y1230H alteration as a potential resistance mechanism.

Lung cancer in patients who have never smoked - an emerging disease

Lung cancer is the most common cause of cancer-related deaths globally. Although smoking-related lung cancers continue to account for the majority of diagnoses, smoking rates have been decreasing for several decades. Lung cancer in individuals who have never smoked (LCINS) is estimated to be the fifth most common cause of cancer-related deaths worldwide in 2023, preferentially occurring in women and Asian populations. As smoking rates continue to decline, understanding the aetiology and features of this disease, which necessitate unique diagnostic and treatment paradigms, will be imperative. New data have provided important insights into the molecular and genomic characteristics of LCINS, which are distinct from those of smoking-associated lung cancers and directly affect treatment decisions and outcomes. Herein, we review the emerging data regarding the aetiology and features of LCINS, particularly the genetic and environmental underpinnings of this disease as well as their implications for treatment. In addition, we outline the unique diagnostic and therapeutic paradigms of LCINS and discuss future directions in identifying individuals at high risk of this disease for potential screening efforts.

MET fusions are targetable genomic variants in the treatment of advanced malignancies

Targeted therapy for malignancies has developed rapidly in recent years, benefiting patients harboring genetic mutations sensitive to relevant tyrosine kinase inhibitors (TKIs). With the development of targeted sequencing techniques, an increasing number of detectable genomic alterations in malignancies, including MET fusions, have been revealed. MET fusions, although rare among malignancies, might be functional driver genes that participate in activating downstream signaling pathways and promoting cell proliferation. Therefore, it is believed that MET fusions could be targetable genomic variants of MET, and inhibition of MET is considered an optionable therapeutic choice for patients harboring MET fusions. According to the summary presented in this review, we recommend MET-TKIs as suitable treatment agents for patients harboring primary MET fusions. For patients harboring acquired MET fusions after the development of resistance to TKIs targeting primary genomic alterations, such as sensitive EGFR mutations, treatment with a MET-TKI alone or in combination with TKIs targeting primary genomic alterations, such as EGFR-TKIs, is hypothesized to be a reasonable option for salvage treatment. In summary, MET fusions, despite their low incidence, should be taken into consideration when developing treatment strategies for cancer patients.

Clinical characteristics and targeted therapy of different gene fusions in non-small cell lung cancer: a narrative review

Background and Objective

Lung cancer is the most fatal malignant tumor in the world. Since the discovery of driver genes, targeted therapy has been demonstrated to be superior to traditional chemotherapy and has revolutionized the therapeutic landscape of non-small cell lung cancer (NSCLC). The remarkable success of tyrosine kinase inhibitors (TKIs) in patients with epidermal growth factor receptor (EGFR) mutations and anaplastic lymphoma kinase (ALK) fusions has shifted the treatment from platinum-based combination chemotherapy to targeted therapy. Although the incidence rate of gene fusion is low in NSCLC, it is of great significance in advanced refractory patients. However, the clinical characteristics and the latest treatment progress of patients with gene fusions in lung cancer have not been thoroughly explored. The objective of this narrative review was to summarize the latest research progress of targeted therapy for gene fusion variants in NSCLC to improve understanding for clinicians.

Methods

We conducted a search of PubMed database and American Society of Clinical Oncology (ASCO), the European Society for Medical Oncology (ESMO), and World Conference on Lung Cancer (WCLC) abstracts meeting proceedings from 1 January 2005 to 31 August 2022 with the following keywords "non-small cell lung cancer", "fusion", "rearrangement", "targeted therapy" and "tyrosine kinase inhibitor".

Key Content and Findings

We comprehensively listed the targeted therapy of various gene fusions in NSCLC. Fusions of ALK, ROS proto-oncogene 1 (ROS1), and rearranged during transfection proto-oncogene (RET) are relatively more common than others (NTRK fusions, NRG1 fusions, FGFR fusions, etc.). Among ALK-rearranged NSCLC patients treated with crizotinib, alectinib, brigatinib, or ensartinib, the Asian population exhibited a slightly better effect than the non-Asian population in first-line therapy. It was revealed that ceritinib may have a slightly better effect in the non-Asian ALK-rearranged population as first-line therapy. The effect of crizotinib might be similar in Asians and non-Asians with ROS1-fusion-positive NSCLC in first-line therapy. The non-Asian population were shown to be more likely to be treated with selpercatinib and pralsetinib for RET-rearranged NSCLC than the Asian population.

Conclusions

The present report summarizes the current state of fusion gene research and the associated therapeutic methods to improve understanding for clinicians, but how to better overcome drug resistance remains a problem that needs to be explored.

Identification of MET fusions as novel therapeutic targets sensitive to MET inhibitors in lung cancer

INTRODUCTION

Alterations in the MET gene, including amplifications and exon 14 skipping mutations, have been identified as actionable oncogenic alterations. However, MET fusions are rarely detected in lung cancer, and their sensitivity to therapeutics has not been systematically analyzed.

METHODS

The data from 30876 lung cancer patients from the LAVA database and 7966 patients from cBioPortal database were screened. Basic demographic and clinical information for the patients harboring MET fusions were collected. A lung squamous cell cancer patient harboring a novel EML4-MET fusion was treated with crizotinib. Additionally, a literature review was performed to summarize the cases of patients harboring MET fusions and their treatment information.

RESULTS

MET fusions were found in only 0.2% to 0.3% of lung cancer patients and appeared in almost all exons of the MET gene. Intragenic MET fusions were found in 52.6% (41/78) of the included patients. Crizotinib was effective for MET fusions, including a novel identified EML4-MET fusion, even after the failure of multiple lines of treatment. This result suggested that acquired MET fusions become more regionally selective, as they usually occurred in exons encoding the extracellular region. Interestingly, the MET-fused genes in primary MET fusions or acquired MET fusions were very different, which indicated the different functions and influences of the disease.

CONCLUSION

MET fusions are rare, and half of the fusion types were intragenic fusions. Lung cancer patients harboring primary or acquired MET fusions could benefit from crizotinib. In addition, EML4-MET was first reported in this study as a novel MET fusion type.