Ivosidenib: A Review in Advanced Cholangiocarcinoma.

Ivosidenib (Tibsovo), a first-in-class, oral small molecule, potent and selective inhibitor of mutant isocitrate dehydrogenase 1 (mIDH1), is approved in the EU and USA for the treatment of adults with pretreated, advanced, mIDH1 cholangiocarcinoma (CCA). It is presumed to exert its cytostatic effects in this setting by suppressing 2-hydroxyglutarate, an oncometabolite produced by mIDH1 that impairs cellular differentiation and promotes tumorigenesis. In the multinational phase 3 ClarIDHy study in patients with pretreated, advanced mIDH1 CCA, monotherapy with ivosidenib once daily significantly prolonged progression-free survival (PFS) and almost doubled the disease control rate compared with placebo. Moreover, it had a favourable effect on overall survival (OS), which was also significantly prolonged after correcting for a high rate of crossover from the placebo group (permitted by the trial protocol). Ivosidenib treatment preserved health-related quality of life (HRQOL) relating to physical function, pain and appetite loss/eating and was generally well tolerated, with the most common treatment-emergent adverse events being low-grade diarrhoea, nausea and fatigue. Thus, ivosidenib represents a novel and valuable targeted therapy for the subset of patients with pretreated, advanced CCA tumors harbouring mIDH1.