Efficacy is most consistently demonstrated in FGFR2 fusion–positive intrahepatic cholangiocarcinoma and FGFR3-mutant urothelial cancer (Borad et al. 2023, Meric-Bernstam et al. 2022, Rodon et al. 2023). The gene discussed is FGFR2; the disease is intrahepatic cholangiocarcinoma.