New Therapy for Low-Grade Glioma

From 1 August 2026, vorasidenib is available on the Pharmaceutical Benefits Scheme (PBS) for eligible patients with grade 2 IDH-mutant astrocytoma or oligodendroglioma. It is the first new treatment in more than 20 years for these rare brain tumours and the first targeted therapy approved in Australia for this patient population.

Vorasidenib is an oral therapy that inhibits mutant isocitrate dehydrogenase (IDH) 1 and IDH2 enzymes. Mutations in these enzymes can promote tumour growth through the production of the oncometabolite 2-hydroxyglutarate (2-HG).

Grade 2 IDH-mutant gliomas are rare, slow-growing brain tumours that typically affect younger adults. Management typically involves surgical resection. This may be followed by radiotherapy and chemotherapy, although active surveillance may be appropriate for low-risk patients.

The double-blind phase III INDIGO trial enrolled patients with residual or recurrent grade 2 IDH-mutant astrocytoma or oligodendroglioma who had undergone surgery as their only previous treatment. Compared with placebo, patients in the vorasidenib group demonstrated significantly prolonged progression-free survival (median 27.7 months vs. 11.1 months) and delayed need for subsequent interventions.

Common adverse effects reported with vorasidenib include fatigue, headache, diarrhoea, nausea, and elevated liver enzymes. Liver function should be monitored regularly during treatment, particularly during the first year of therapy, due to the risk of hepatotoxicity.