IIB-5

IIB-5 is a novel aminopyrimidine-based small molecule inhibitor of the epidermal growth factor receptor (EGFR), specifically designed to overcome acquired resistance in non-small cell lung cancer (NSCLC). It targets the EGFR L858R/T790M/C797S triple mutation, which frequently arises as a resistance mechanism following treatment with third-generation EGFR inhibitors such as osimertinib. Developed using the inhibitor brigatinib as a structural reference, IIB-5 has demonstrated potent biochemical inhibition of the triple-mutant kinase (IC50 of 18.81 nM) and significant antiproliferative activity against resistant Ba/F3 cell lines. Its design aims to provide a therapeutic option for patients who have exhausted current standard-of-care EGFR-targeted therapies.