Design and synthesis of an erdafitinib-based selective FGFR2 degrader

This study aimed to develop a novel degrader capable of selectively degrading fibroblast growth factor receptor 2 (FGFR2) to overcome the issues of drug resistance and adverse reactions associated with traditional inhibitors in the treatment of FGFR2-driven tumors. Erdafitinib was employed as the targeting ligand, and its aliphatic amine site was conjugated with a CRBN E3 ligase ligand to design and synthesize a series of PROTAC molecules with different linkers. Screening was performed in KATO III cells with high FGFR2 expression, leading to the identification of LC-JD-6 as a potent degrader. Experimental results demonstrated that LC-JD-6 effectively induced FGFR2 protein degradation with a half-maximal degrading concentration (DC₅₀) of 121.4 nM, and this effect exhibited time- and concentration-dependence. Assessed at the cellular level, LC-JD-6 has a half-maximal inhibitory concentration in the KATO III (IC₅₀) of 96.0 nM and showed low inhibitory activity in normal cells. Selectivity analysis revealed that LC-JD-6 specifically degraded FGFR2 with minimal impact on other FGFR subtypes. Further studies confirmed that LC-JD-6 also efficiently reduced the expression of FGFR2 on the cell membrane surface. In conclusion, this study successfully developed LC-JD-6, a novel FGFR2-selective degrader, and for the first time confirmed its ability to degrade the membrane-bound form of FGFR2. This work provides an innovative targeted protein degradation strategy for the treatment of FGFR2-driven tumors and holds significant potential for clinical application.