CK-101 is an orally available third-generation and selective inhibitor of certain epidermal growth factor receptor (EGFR) activating mutations, including the resistance mutation T790M, with potential antineoplastic activity. Activating mutations in the tyrosine kinase domain of EGFR are found in approximately 20% of patients with advanced Non-Small Cell Lung Cancer (NSCLC). Compared to chemotherapy, first-generation EGFR inhibitors significantly improved ORR and progression-free survival in previously untreated NSCLC patients carrying EGFR mutations. However, tumor progression could develop due to resistance mutations, often within months of treatment with first-generation EGFR inhibitors. CK-101 designed to be highly selective against the T790M mutation while sparing wild-type EGFR, thereby improving tolerability and safety profiles. Compared to some other EGFR inhibitors, CK-101 may have therapeutic benefits in tumors with T790M-mediated drug resistance. This agent shows minimal activity against wild-type EGFR (WT EGFR) and does not cause dose-limiting toxicities that occur during the use of non-selective EGFR inhibitors, which also inhibit WT EGFR.