Use, access, and initial outcomes of off-label ivosidenib in patients with IDH1 mutant glioma.

Background: Isocitrate dehydrogenase (IDH) is commonly mutated (mIDH) in gliomas, and this mutant enzyme produces the oncometabolite 2-hydroxyglutarate (2HG). 2HG promotes gliomagenesis and is implicated in epileptogenesis. Ivosidenib (IVO), a small molecule oral mIDH1 inhibitor, is FDA-approved for mIDH1 newly diagnosed and relapsed/refractory acute myeloid leukemia.