EGFR exon 20 insertions in advanced non-small cell lung cancer: A new history begins

Although targeted therapy is standard of care in a large subset of oncogenic addicted non-small cell lung cancers (NSCLC), until recently, this therapeutic approach has not been feasible for all genomic alterations such as for those tumors harboring Epidermal Growth Factor Receptor (EGFR) exon 20 insertion (ex20ins) mutations. Despite being the third most common EGFR mutation, a limited efficacy of first- and second-generation EGFR tyrosine kinase inhibitors (TKI) exists. This is related to the heterogeneity at the molecular level in EGFR ex20ins mutation variants and the finding that this mutation promotes active kinase conformation but does not increase the affinity for EGFR TKI. As a result, the prognosis of this population is diminished. Therefore, chemotherapy remained the most suitable strategy in this subset of EGFR mutant NSCLC patients. Recently, new treatment strategies have been reported in this landscape, either with new EGFR TKI or bispecific antibodies, which may establish a new standard of care in the coming future for these patients. Future research should focus on elucidating the oncogenic degree of all EGFR ex20ins variants, the potential role of combination strategies either with chemotherapy or immune checkpoint inhibitors, and the most appropriate first-line treatment strategy in this subgroup. Finally, the knowledge of mechanisms of acquired resistance to these new agents upon progression is a priority for personalising treatment at that time. It is in this framework, that we provide a thorough overview on this subject.     

第三代EGFR-TKIs治疗晚期非小细胞肺癌的耐药机制及应对策略研究进展

表皮生长因子受体（EGFR）酪氨酸激酶抑制剂（TKIs）是具有EGFR基因敏感突变的晚期非小细胞肺癌（NSCLC）患者的一线治疗药物。第一、二代EGFR-TKIs可有效治疗EGFR敏感突变的NSCLC,EGFR第20号外显子的T790M突变是第一、二代EGFR-TKIs的主要耐药机制。以奥西替尼为代表的第三代EGFR-TKIs治疗耐药后出现T790M突变的患者疗效显著,给晚期肺癌患者带来更多的生存获益。然而第三代EGFR-TKIs仍不可避免地出现耐药。本文对第三代EGFR-TKIs治疗晚期NSCLC耐药机制及应对策略的研究进展进行综述。     

Transient Asymptomatic Pulmonary Opacities During Osimertinib Treatment and its Clinical Implication

Introduction

Osimertinib is an oral, potent, irreversible third-generation EGFR tyrosine kinase inhibitor approved for the treatment of T790M-positive NSCLC patients who failed first- or second-generation EGFR tyrosine kinase inhibitors. Interstitial lung disease (ILD) is a rare complication with osimertinib, occurring in 1% to 3% of patients. Recently, a relatively high incidence of transient asymptomatic pulmonary opacities (TAPOs), which are different from ILD, has been described. However, its clinical implication has not been fully determined yet.

EGFR L792H and G796R: Two Novel Mutations Mediating Resistance to the Third-Generation EGFR Tyrosine Kinase Inhibitor Osimertinib

Background

The third-generation EGFR tyrosine kinase inhibitor osimertinib has been approved in many countries to treat advanced NSCLC in patients with the EGFR T790M mutation. As the development of acquired resistance is inevitable, it is urgent that the mechanisms of such resistance be clarified.

Dynamic Changes and Drug-Induced Selection of Resistant Clones in a Patient With EGFR-Mutated Adenocarcinoma That Acquired T790M Mutation and Transformed to Small-Cell Lung Cancer

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Osimertinib Plus Durvalumab versus Osimertinib Monotherapy in EGFR T790M–Positive NSCLC following Previous EGFR TKI Therapy: CAURAL Brief Report

Introduction

Osimertinib is a third-generation EGFR-tyrosine kinase inhibitor (TKI). Durvalumab is an anti–programmed death ligand 1 monoclonal antibody. The phase III open-label CAURAL trial (NCT02454933) investigated osimertinib plus durvalumab versus osimertinib monotherapy in patients with EGFR-TKI sensitizing and EGFR T790M mutation–positive advanced NSCLC and disease progression after EGFR-TKI therapy.

Osimertinib for EGFR T790M mutation-positive non-small cell lung cancer

Introduction: Significant advances have been made since the development of epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) targeting EGFR mutations in non-small-cell lung cancer (NSCLC), however, lung cancer cells eventually acquire resistance to those agents. Osimertinib (AZD9291) has been developed as 3^rd generation EGFR-TKI with activities against sensitizing mutations and T790 M resistance mutation, which account for about 50% of the mechanisms of acquired resistance to 1^st or 2^nd generation EGFR-TKIs. A recent phase I/II clinical trial with osimertinib for advanced NSCLC patients with known sensitizing EGFR mutations and documented disease progression on prior EGFR-TKIs revealed promising effect with acceptable toxicities.

Areas covered: This article summarizes current understanding and available preclinical and clinical data on osimertinib and also discusses future directions. The literature search included PubMed and the latest articles from international conferences.

Expert commentary: The development of osimertinib has provided new therapeutic options for NSCLC patients harboring T790 M. Compared with other EGFR-TKIs including rociletinib, osimertinib seems to possess an advantage with respect to the effect and safety profile among existing EGFR-TKIs. However, tumor progression still occurs even when treating with osimertinib. A further understanding of the mechanisms of resistance is eagerly anticipated in order to develop next generation EGFR-TKIs.