Osimertinib for Advanced EGFR-positive NSCLC Patients

Lung cancer is the leading cause of cancer incidence (11.6%) and mortality (18.4%) globally\[1\]. Development of targeted therapies in the context of precision medicine changed the way lung cancer was diagnosed and treated. Small molecule inhibitors, like tyrosine kinase inhibitors (TKIs), are now standard first-line therapy for EGFR-positive non-small cell lung cancer (NSCLC). First-generation EGFR-TKIs gefitinib and erlotinib bind competitively to the ATP-binding site of EGFR TK domain. This binding in second-generation TKI afatinib is irreversible. These drugs have improved better outcome compared to standard conventional chemotherapy In spite of this, more than half of the patients with an EGFR TKI treatment develop resistance. Deletion in exon 19 and single point substitution L858R in exon 21 accounting for 44% and 41% of all EGFR mutations, respectively are the most common mutations in EGFR gene which cause this resistance in the patients. Asia has the highest prevalence of EGFR mutations (38.4%), followed by America (24.4%) and Europe (14.1%). Median progression-free survival of EGFR mutated NSCLC patients under erlotinib or gefitinib has been around 12 months and 5-year survival was 15%