Case Report: Durable partial response to icotinib plus crizotinib in a lung adenocarcinoma patient with double uncommon EGFR G719D/L861Q mutations and an acquired novel CUX1-MET fusion

Icotinib in a lung adenocarcinoma patient with acquired EGFR 19del/C797S mutation-mediated resistance to osimertinib: a case report

Based on the FLAURA and AURA III trials, compared to first- and second-generation epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKIs), osimertinib provides a longer overall survival benefit for patients with untreated EGFR mutated non-small cell lung cancer. Similar to other EGFR-TKIs, drug resistance is, however, inevitable. The most common mechanism of acquired resistance to first-line osimertinib therapy is the C797S mutation, which accounts for 6% of cases. In view of the current challenges of the development of the next generation of EGFR inhibitors, the mechanism of third-generation targeted drug resistances and targeted strategies are key for further exploration. Our case report discusses a female patient with advanced lung adenocarcinoma carrying the EGFR exon19 E746_A750delinsIP mutation who received osimertinib as first-line therapy and acquired C797S resistance during treatment. The patient was then treated with icotinib for 8 months until the disease progressed. Icotinib may be effective in patients with the EGFR 19del-C797S resistant mutation acquired after osimertinib treatment.

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.

MET alterations detection platforms and clinical implications in solid tumors: a comprehensive review of literature

MET alterations, including MET exon 14 skipping variants, MET amplification, MET overexpression, and MET fusion, play pivotal roles in primary tumorigenesis and acquired resistance to targeted therapies, especially EGFR tyrosine kinase inhibitors. They represent important diagnostic, prognostic, and predictive biomarkers in many solid tumor types. However, the detection of MET alterations is challenging due to the complexity of MET alterations and the diversity of platform technologies. Therefore, techniques with high sensitivity, specificity, and reliable molecular detection accuracy are needed to overcome such hindrances and aid in biomarker-guided therapies. The current review emphasizes the role of MET alterations as oncogenic drivers in a variety of cancers and their involvement in the development of resistance to targeted therapies. Moreover, our review provides an overview of and recommendations on the selection of various cross-platform technologies for the detection of MET exon 14 skipping variants, MET amplification, MET overexpression, and MET fusion. Furthermore, challenges and hurdles underlying these common detection platforms are discussed.

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.

Analysis of rare fusions in NSCLC: Genomic architecture and clinical implications

OBJECTIVES

Molecular diagnosis for targeted therapies has been improved significantly in non-small-cell lung cancer (NSCLC) patients in recent years. Here we report on the prevalence of rare fusions in NSCLC and dissect their genomic architecture and potential clinical implications.

MATERIALS AND METHODS

Overall, n = 5554 NSCLC patients underwent next-generation sequencing (NGS) for combined detection of oncogenic mutations and fusions either at primary diagnosis (n = 5246) or after therapy resistance (n = 308). Panels of different sizes were employed with closed amplicon-based, or open assays, i.e. anchored multiplex PCR (AMP) and hybrid capture-based, for detection of translocations, including "rare" fusions, defined as those beyond ALK, ROS1, RET and <0.5 % frequency in NSCLC.

RESULTS

Rare fusions involving EGFR, MET, HER2, BRAF and other potentially actionable oncogenes were detected in 0.5% (n = 26) of therapy-naive and 2% (n = 6) TKI-treated tumors. Detection was increased using open assays and/or larger panels, especially those covering >25 genes, by approximately 1-2% (p = 0.001 for both). Patient characteristics (age, gender, smoking, TP53 co-mutations (56%), or mean tumor mutational burden (TMB) (4.8 mut/Mb)) showed no association with presence of rare fusions. Non-functional alterations, i.e. out-of-frame or lacking kinase domains, comprised one-third of detected rare fusions and were significantly associated with simultaneous presence of classical oncogenic drivers, e.g. EGFR or KRAS mutations (p < 0.001), or use of larger panels (frequency of non-functional among the detected rare fusions 57% for 25+ gene- vs. 12% for smaller panels, p < 0.001). As many rare fusions were identified before availability of targeted therapy, mean survival for therapy-naïve patients was 23.8 months, comparable with wild-type tumors.

CONCLUSION

Approximately 1-2% of advanced NSCLC harbor rare fusions, which are potentially actionable and may support diagnosis. Routine adoption of broad NGS assays capable to identify exact fusion points and potentially retained protein domains can increase the yield of therapeutically relevant molecular information in advanced NSCLC.

The novel EGFR mutations (p.E746_S752delinsI, p.T751_I759delinsG, p.L747_S752delinsAA) in patients with non-small cell lung cancer and the clinical treatment strategy: three case reports

Epidermal growth factor receptor (EGFR) is an established driver gene in non-small cell lung cancer (NSCLC) and the common Exon 19 del mutation (p.E746_A750 del) has exhibited remarkable responses for EGFR tyrosine kinase inhibitors (TKIs). However, there is even less comprehension of the treatment strategy in NSCLC patients harboring uncommon Exon 19 delins mutation. Here, we identified three novel EGFR Exon 19 mutations (p.E746_S752delinsI, p.T751_I759delinsG, p.L747_S752delinsAA), and described the clinical treatment process. To our knowledge, the EGFR p.E746_S752delinsI mutation of the patient with advanced NSCLC could benefit from the treatment with Icotinib. Otherwise, for the NSCLC patients with early-stage, one harboring p.T751_I759delinsG mutation had an excellent recovery and the other harboring p.L747_S752delinsAA experienced a relapse after receiving horacoscopic radical resection, which means the patients with different Exon 19 delins mutation might have different prognosis. Our study also demonstrated that next-generation sequencing (NGS) is a crucial tool in guiding clinical treatment decisions in NSCLC. Furthermore, the real incidence of these mutation is not known, the routinely use of NGS surely will increase the detection of EGFR del-ins respect to the old tools used to screen for EGFR mutations.

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.