Derazantinib is primarily used in the treatment of cancers driven by aberrant fibroblast growth factor receptor (FGFR) signaling. It functions as a selective inhibitor of FGFR1, FGFR2, and FGFR3, making it a valuable candidate for tumors with FGFR gene fusions, amplifications, or mutations. It has shown promising activity in cholangiocarcinoma (bile duct cancer), particularly in patients with FGFR2 gene fusions, which are common in this cancer type. Clinical trials have demonstrated tumor shrinkage and disease stabilization in patients who have progressed on standard therapies. Additionally, derazantinib is being investigated in other solid tumors such as urothelial carcinoma and glioblastoma where FGFR pathway dysregulation plays a role. Its oral bioavailability and targeted mechanism support its use in long-term treatment regimens with manageable side effects.