Version July 2025
IDH: isocitrate dehydrogenase; MRI: magnetic resonance imaging; PCV: procarbazine, lomustine, vincristine; RT: radiation therapy; TMZ: temozolomide; WHO: World Health Organization.
* Selection is individualized. Both temozolomide regimens are considered appropriate by expert groups for grade 4 IDH-mutant astrocytomas, and comparative evidence in these tumors is not available. There is no evidence to support one regimen as "more aggressive" than another in terms of efficacy, and the risk of hematologic toxicity may be higher with concurrent therapy, particularly in females.
¶ Watchful waiting has traditionally been favored for most patients with a grade 2 IDH-mutant astrocytoma after gross total resection, who are at low risk for early clinical progression and may not require further therapy for many years. IDH-targeted therapy may be an option to prolong progression-free survival, although patients without measurable disease were not included in the INDIGO trial, and safety data for very long-term treatment with vorasidenib are only available for a limited number of patients treated on phase 1 trials.
Δ There is no consensus on size of residual tumor as a criteria for determining next line of therapy, and clinicians must use judgement in selecting patients for vorasidenib who are felt to be candidates for safe postponement of RT plus chemotherapy. Multidisciplinary conversations are encouraged. Refer to UpToDate content on management of IDH-mutant astrocytomas for further details.