2H-pyrazolo[3,4-d]pyrimidin-4-amine derivatives as novel selective fibroblast growth factor receptor 2 (FGFR2) inhibitors

Although FGFR2 is a well-validated oncogenic target, no selective FGFR2 inhibitors have been approved for clinical use. In this study, we report the discovery of 2H-pyrazolo[3,4-d]pyrimidin-4-amine derivative as novel, irreversible FGFR2 inhibitors. The optimal compound, PLW559, potently inhibited FGFR2 with an IC(50) value of 13.59 nM and demonstrated exceptional selectivity over FGFR1, FGFR3, and FGFR4. Covalent binding to the target was confirmed by mass spectrometry. In cellular models, PLW559 exhibited potent and selective antiproliferative effects against FGFR2-driven cancer cells, effectively suppressed downstream FGFR2 signalling and induced cancer cell apoptosis. Notably, it showed minimal activity in non-FGFR2-dependent cells. This work presents a new class of selective FGFR2 inhibitors based on a novel scaffold, offering promising lead compounds for the development of FGFR2-target therapies.