FGF23 and hyperphosphatemia: Table 1 summarizes the key clinical studies on FGFR inhibitors in FGFR2 fusion/rearrangement-positive iCCA patients (Javle et al., 2021; Goyal et al., 2023; Park et al., 2024; Javle et al., 2020). These studies indicated that pemigatinib, futibatinib, erdafitinib, derazantinib, and infigratinib all showed favorable efficacy in these patients. The most common AEs reported in these trials was hyperphosphatemia, occurring in 60%–80% of cases, which was related to the FGF23/FGFR signaling axis in phosphate homeostasis (Kommalapati et al., 2021).