IDH1 and cholangiocarcinoma: For example, the IDH1-specific small-molecule inhibitor ivosidenib (p.Arg132 missense mutation), an approved drug for acute myeloid leukemias and cholangiocarcinomas, and vorasidenib were associated with a reduced tumor 2-hydroxyglutarate concentration, decreased tumor cell proliferation and immune activation in a phase 1 trial of low-grade glioma [25].