EGFR tyrosine kinase inhibitors in non-small cell lung cancer: treatment paradigm, current evidence, and challenges.

Therapy with epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) for patients with EGFR-mutated non-small cell lung cancer (NSCLC) has been shown to have superior outcomes when compared to chemotherapy. First-generation EGFR TKI, including gefitinib and erlotinib, and second-generation EGFR TKI, including afatinib and dacomitinib, proved to be effective in patients with NSCLC harboring EGFR-sensitizing mutation. Later, resistance mutations were identified. Consequently, osimertinib, a third-generation EGFR TKI, was studied and demonstrated activity against EGFR-sensitizing and resistant mutations. Osimertinib moved recently to the first-line setting with the positive results of the FLAURA (AZD9291 Versus Gefitinib or Erlotinib in Patients With Locally Advanced or Metastatic Non-small Cell Lung Cancer) trial. The use of these drugs is limited by their cost and availability mainly in middle- to low-income countries.