Lin Zhang, Xueru Liu, Wuqing Deng, Tanyuxuan Yang, Ke Gui, Yuepiao Cai, Yongheng Chen, Xiaojuan Chen,
Biochemical Pharmacology, 2026, 118560,
https://doi.org/10.1016/j.bcp.2026.118560.
Fibroblast growth factor receptors FGFR2 and FGFR4 are oncogenic drivers in multiple cancers, yet most approved FGFR inhibitors lack subtype selectivity and are prone to acquired resistance. Here we identify F-30 as, to our knowledge, the first covalent inhibitor with preferential activity toward both FGFR2 and FGFR4 through covalent targeting of a conserved P-loop cysteine. Structural analyses reveal that differential engagement of the P-loop and surrounding binding environment contributes to paralog discrimination. Consistent with these structural observations, F-30 showed an approximately 12-fold lower KI and 13-fold higher kinact/KI for FGFR2 than for FGFR1, whereas their kinact values were comparable. These results indicate that the preference for FGFR2 over FGFR1 is primarily established during pre-covalent recognition. F-30 retained strong activity against multiple clinically relevant FGFR2 resistance-associated mutations but showed reduced potency against gatekeeper mutations. In cellular models, F-30 preferentially inhibited the proliferation of FGFR2/4–driven cancer cells, while substantially weaker pathway inhibition was observed in FGFR1- and FGFR3-driven models than in FGFR2-dependent cells. Taken together, these findings identify structural and kinetic features that contribute to the subtype-selective profile of F-30 and may guide the design of covalent FGFR inhibitors targeting the conserved P-loop cysteine.
