Overcoming Resistance to EGFR Inhibitors in NSCLC

Background: The clarification of several molecular pathways underlying the tumorigenesis has led to the development of several targeted drugs that have substantially improved the treatment of Non-Small-Cell Lung Cancer (NSCLC). The Epidermal Growth Factor Receptor (EGFR) is the target of several Tyrosine-Kinase Inhibitors (TKIs), some of them approved for treatment and others currently in clinical development. EGFR-TKIs markedly improve progression-free survival of patients with advanced NSCLC with EGFR mutations compared with chemotherapy. Methods: We undertook a structured search of bibliographic databases for peer-reviewed research literature using a focused review question. Results: Although first-and second-generation agents offer in target population (with EGFR mutations) a substantial improvement of outcomes compared with standard chemotherapy, unfortunately, drug resistance develops after initial benefit, through a variety of mechanisms. Novel-(third) generation EGFR inhibitors have a selective mechanism of action and are currently in advanced clinical development, producing encouraging results in patients with acquired resistance to previous generation agents. Conclusion: The search for new drugs or strategies to overcome the TKI resistance in patients with EGFR mutations is to be considered a priority for the improvement of outcomes in the treatment of advanced NSCLC, and third-generation EGFR inhibitors are the most promising approach to the issue.