For grade 3 gliomas, a phase 1 study (NCT02481154) of vorasidenib in recurrent IDH-mutant gliomas, including a small grade 3 subset, reported a median PFS of 36.8 months for non-enhancing tumors but only 3.6 months for enhancing tumors—common in grade 3—suggesting limited efficacy in aggressive cases (5). Here, IDH1 is linked to glioma.