“…The T790M mutation is the predominant mechanism of acquired resistance to afatinib in primary tumors, with osimertinib demonstrating significant efficacy against this mutation [ 78 , 83 ]. In primary malignancies, the T790M mutation is the most common route of acquired resistance to afatinib; osimertinib has shown notable effectiveness against this mutation [119] , [120] , [121] . However, previous studies [122] indicate that the EGFR L718Q mutation, with or without the T790M mutation, accounts for about 10% of all patients exhibiting osimertinib resistance.…”