A Case Report of Successful Treatment With Crizotinib to Overcome Resistance to Osimertinib in an EGFR Mutated Non-Small-Cell Lung Cancer Patient Harboring an Acquired MET Exon 14 Mutation

Unfavorable response to capmatinib for MET exon14 skipping after first-line osimertinib in a patient with EGFR-mutated lung adenocarcinoma: A case report and literature review

MET exon14 skipping mutations (METex14s) are rarely reported as a potential resistance mechanism to EGFR tyrosine kinase inhibitors (TKIs). The efficacy of targeted therapy against METex14s emerging after osimertinib resistance is uncertain. Herein, we report a case of EGFR-mutated metastatic lung adenocarcinoma in which METex14 was detected in a re-biopsy upon first-line osimertinib resistance. The patient received capmatinib monotherapy as third-line therapy, which was ineffective, followed by an exceptional response to salvage therapy with afatinib. This report highlights the heterogeneity of EGFR-TKI resistance and that targeting rare resistance mechanisms remains challenging.

Acquired resistance mechanisms to osimertinib: The constant battle

Lung cancer is the leading cause of cancer-related mortality worldwide. Detectable driver mutations have now changed the course of lung cancer treatment with the emergence of targeted therapy as a novel strategy that widely improved lung cancer prognosis, especially in metastatic patients. Osimertinib (AZD9291) is an irreversible third-generation epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) used to treat stage IV EGFR-mutated non-small-cell lung cancer. It was initially designed to target both EGFR-activating mutations and the EGFR T790M mutation as well, which is the most common resistance mechanism to first- and second-generation EGFR-TKIs. Following the FLAURA trial, osimertinib is now widely used in the first-line setting. However, resistance to osimertinib inevitably develops, with numerous mechanisms leading to its resistance, classified into two main categories: EGFR-dependent and EGFR-independent mechanisms. While EGFR-dependent mechanisms consist mainly of the C797S EGFR mutation, EGFR-independent mechanisms include bypass pathways, oncogenic fusions, and phenotypic transformation, among others. This review summarizes the molecular resistance mechanisms to osimertinib, with the aim of identifying novel therapeutic approaches to overcome osimertinib resistance and improve patient outcome.

New Strategies and Novel Combinations in EGFR TKI-Resistant Non-small Cell Lung Cancer

OPINION STATEMENT

Osimertinib is the current standard-of-care for the first-line treatment of Epidermal Growth Factor Receptor (EGFR)-mutant non-small cell lung cancer (NSCLC). Progression after osimertinib ineluctably occurs, and standard of care treatment options beyond progression have mainly included next-line platinum doublet chemotherapy. With better understanding of the varied molecular mechanisms of resistance to osimertinib, several opportunities for the use of targeted agents are emerging that include MET amplification, observed in 15% of patients, and resistant EGFR mutations, including C797S in 7% of patients. Evidence for the use of targeted therapies in such situations is mostly based on case reports, but clinical trials are being conducted with MET inhibitors, such as amivantamab, an EGFR-MET bispecific antibody, or next-generation EGFR inhibitors, such as patritumab-deruxtecan, a HER3 antibody drug conjugate. In this review, we outline our proposed approach to current clinical practice for patients with EGFR mutant, osimertinib-resistant NSCLC which includes the following potential strategies: - Continuation of osimertinib beyond progression following local ablative treatment of oligoprogressive disease, - Tissue rebiopsy of progressive site and possibly concurrent liquid biopsy to evaluate for mechanism of resistance utilizing comprehensive genomic profiling, -Discussion at a molecular tumor board for assessment for enrollment in clinical trials/expanded access program if available with innovative drugs or possible off-label use of available targeted agents, based on the results of molecular profiling, -If no mechanism of resistance identified, administration of platinum-based chemotherapy with antiangiogenic agents. The role of immunotherapy will also be addressed given the uncertain benefit.

Case report: Success of tepotinib therapy in overcoming resistance to osimertinib in a patient with EGFR-mutant lung adenocarcinoma with a potential acquired MET exon 14 skipping mutation

Osimertinib is a standard therapy for the treatment of advanced non-small cell lung cancer (NSCLC) harboring epidermal growth factor receptor gene (EGFR) mutations, but most patients with EGFR-mutant NSCLC develop secondary resistance to osimertinib. Mesenchymal-epithelial transition gene (MET) alterations and oncogene fusions have been identified as the most common mechanisms of resistance to osimertinib. However, MET exon 14 skipping mutation (METex14del) as an acquired resistance to osimertinib has rarely been reported. A non-smoking 76-year-old woman was diagnosed with lung adenocarcinoma in the right lower lobe (cT2bN2M1c [pulmonary and bone metastases], cStage IVB). The primary tumor was submitted to cobas^® EGFR Mutation Test v2 (Roche Diagnostics Ltd.), next generation sequencing (Oncomine Comprehensive Assay v3; Thermo Fisher Scientific), the AmoyDx^® Essential NGS panel (Amoy Diagnostics, Xiamen, China), all of which were positive for EGFR L858R and de novo T790M. We administered daily osimertinib (80 mg/day), and achieved a partial response. However, after 14.0 months, computed tomography showed progression of the primary tumor and lung metastases. Re-biopsy of the primary tumor was conducted, and the specimen was submitted to Archer^®MET companion diagnostic for detection of METex14del. Although the primary tumor was negative for METex14del, the re-biopsy specimen was positive for METex14del. We validated that the biopsy specimen of the primary tumor at diagnosis before osimertinib administration was negative for METex14del using local reverse transcription PCR. We administered daily tepotinib (500 mg/day) to the patient as a further-line treatment, and achieved a partial response (tumor shrinkage rate: 34.5%) after 2.0 months, who responded to tepotinib therapy for 8.0 months. We described a patient with lung adenocarcinoma harboring METex14del as a potential acquired resistance to osimertinib, who responded to subsequent tepotinib therapy. Re-biopsy and re-analysis of genetic profiles should be considered in NSCLC patients who develop osimertinib resistance.

EGFR-mutant NSCLC: monitoring the molecular evolution of tumors in 2022

INTRODUCTION

Epidermal growth factor receptor (EGFR) activating mutations define a subset of advanced, metastatic non-small cell lung cancers (NSCLCs), that was historically identified along with the clinical development of specific EGFR tyrosine kinase inhibitors (TKIs), opening the era of precision medicine in thoracic oncology.

AREAS COVERED

Progression after EGFR TKIs is a major challenge for patients, as it occurs ineluctably along with disease evolution. Osimertinib is the current standard-of-care for the first-line treatment of EGFR-mutant NSCLC. Mechanisms of resistance to osimertinib are challenging to identify, and are dominated by MET pathway activation, and acquired EGFR mutations.

EXPERT OPINION

The current vision for clinical practice in patients with EGFR-mutant NSCLC developing disease progression after osimertinib includes the following 5 steps:- continuation of osimertinib beyond progression, and local treatment of oligoprogressive disease, - comprehensive genomic profiling based on tissue rebiopsy of progressing sites, - access to new treatment agents through clinical trials, - molecular tumor board to discuss the off-label use of targeted agents, depending on the availability of drugs and/or expanded access programs - chemotherapy may be the best choice, based on combination of platinum-based regimen and antiangiogenic agents and possibly immune checkpoint inhibitors.

Resistance to TKIs in EGFR-Mutated Non-Small Cell Lung Cancer: From Mechanisms to New Therapeutic Strategies

Simple Summary

Resistance to tyrosine kinase inhibitors (TKIs) of the epidermal growth factor receptor (EGFR) in advanced mutant non-small cell lung cancer (NSCLC) constitutes a therapeutic challenge. Resistance may occur as a result of EGFR-dependent and independent molecular pathways. The first commonly includes T790M, C797S, L792X and L718X mutations, while the latter pertains to HER2 and MET amplifications, gene rearrangements, disruption in PIK3CA, MAPK signaling and SCLC and epithelial–mesenchymal cells transformation. Liquid biopsies detecting mutant cell-free DNA (cfDNA) have a major potential in the detection of mutant clones before they become clinically apparent. Newer-generation TKIs, bispecific antibodies and antibody-drug conjugates or combinations of TKIs with other TKIs or chemotherapy, immunotherapy and anti-vascular endothelial growth factors (anti-VEGFs) are currently in use or under investigation in EGFR mutant NSCLC. In EGFR mutant NSCLC metastatic to the brain, the blood–brain barrier (BBB) decreases the ability of TKIs to reach the central nervous system (CNS), acting as an additional resistance factor, which can presently be addressed with osimertinib. The potential of rechallenging EFGR TKIs after chemotherapy and combining it with anti-PD-1 immunotherapeutics remains ambivalent. Harnessing nanocarriers to improve drug delivery in EGFR TKIs-resistant NSCLC has been promising in preclinical settings, but it is yet to be determined in a clinical context.

Abstract

Resistance to tyrosine kinase inhibitors (TKIs) of the epidermal growth factor receptor (EGFR) in advanced mutant Non-Small Cell Lung Cancer (NSCLC) constitutes a therapeutic challenge. This review intends to summarize the existing knowledge about the mechanisms of resistance to TKIs in the context of EGFR mutant NSCLC and discuss its clinical and therapeutic implications. EGFR-dependent and independent molecular pathways have the potential to overcome or circumvent the activity of EGFR-targeted agents including the third-generation TKI, osimertinib, negatively impacting clinical outcomes. CNS metastases occur frequently in patients on EGFR-TKIs, due to the inability of first and second-generation agents to overcome both the BBB and the acquired resistance of cancer cells in the CNS. Newer-generation TKIs, TKIs targeting EGFR-independent resistance mechanisms, bispecific antibodies and antibody-drug conjugates or combinations of TKIs with other TKIs or chemotherapy, immunotherapy and Anti-Vascular Endothelial Growth Factors (anti-VEGFs) are currently in use or under investigation in EGFR mutant NSCLC. Liquid biopsies detecting mutant cell-free DNA (cfDNA) provide a window of opportunity to attack mutant clones before they become clinically apparent. Overall, EGFR TKIs-resistant NSCLC constitutes a multifaceted therapeutic challenge. Mapping its underlying mutational landscape, accelerating the detection of resistance mechanisms and diversifying treatment strategies are essential for the management of the disease.