Evaluation of early metabolic changes following vorasidenib using FET PET in patients with IDH-mutant gliomas

The phase-3 INDIGO trial demonstrated that the isocitrate dehydrogenase (IDH) inhibitor vorasidenib significantly prolonged progression-free survival and delayed intervention in patients with CNS WHO grade 2 gliomas. However, conventional MRI showed limited response, with only 11% of patients having objective responses. Studies suggest that serial PET imaging with radiolabeled amino acids, such as O -(2-[¹⁸ F]-fluoroethyl)-L-tyrosine (FET) PET, may provide earlier and more informative assessments of treatment response than MRI. In an initial experience with FET PET, 3 out of 5 patients showed metabolic response to vorasidenib. This highlights FET PET's potential to guide decision-making, though further trials are needed to confirm outcome benefits.