Discovery of Novel 2,4,5-Trisubstituted Pyrimidine Derivatives as Potent and Selective FGFR Inhibitors against Gatekeeper Mutants for the Treatment of NSCLC

Fibroblast growth factor receptors (FGFRs) play a critical role in the regulation of cancer cell proliferation, differentiation, and migration. However, the development of acquired resistance to FGFR inhibitors remains a major challenge in treating non-small cell lung cancer (NSCLC), particularly due to mutations at the gatekeeper residue. In this study, we report the discovery of a series of irreversible FGFR inhibitors targeting gatekeeper mutations in FGFR1–3, utilizing a 2,4,5-trisubstituted pyrimidine scaffold. Through rational design, structure–activity relationship optimization, and pharmacokinetic evaluation, compound ng 12l emerged as a promising candidate. It demonstrated potent inhibition of FGFR1–3 gatekeeper mutations in vitro along with favorable pharmacokinetic properties. The efficacy of 12l in targeting FGFR1 gatekeeper mutations was confirmed in assays using L6-FGFR1^V561M/F cells. Furthermore, in xenograft models using both H1581 and L6-FGFR1^V561M cells, 12l exhibited robust anti-tumor activity with minimal toxicity. These findings position 12l as a promising therapeutic agent for overcoming gatekeeper-mediated resistance in NSCLC.