IDH1 and cholangiocarcinoma: In particular, the Phase 3 ClarIDHy trial demonstrated a significant improvement in progression‐free survival (PFS, primary endpoint of the study) for patients with IDH1 mutant CCA treated with the IDH1 inhibitor ivosidenib in second or third line, as compared to placebo [2.7 months (95% CI, 1.6–4.2) vs. 1.4 months (95% CI, 1.4–1.6); hazard ratio (HR) 0.37, 95% CI, 0.25–0.54; p < 0.0001] [17].