A phase III study including 185 patients with advanced IDH1-mutant cholangiocarcinoma caused significant improvement in progression-free survival (median 2.7 months vs. 1.4 months; HR: 0.37, P < 0.001) when treated with an IDH1 inhibitor named ivosidenib compared to placebo (52). The gene discussed is IDH1; the disease is cholangiocarcinoma.