Early seizure freedom with [¹⁸F]fluorodopa positron emission tomography response after isocitrate dehydrogenase inhibition with vorasidenib: First case report

Vorasidenib, a dual isocitrate dehydrogenase 1/2 (IDH1/2) inhibitor, showed superior efficacy in prolonging progression‐free survival and time to next intervention in IDH ‐mutant grade 2 gliomas. This case is part of an ongoing institutional study exploring the impact of vorasidenib on seizure control and the potential of [ 18 F]fluorodopa (F‐DOPA) positron emission tomography (PET) to detect treatment response earlier than magnetic resonance imaging (MRI). A 52‐year‐old patient with grade 2 IDH ‐mutant 1p19q‐codeleted oligodendroglioma and persistent postoperative seizures received vorasidenib. He achieved early seizure freedom from the first month of therapy without any change of antiseizure medication (ASM). At 3 and 6 months after treatment, MRI showed stable disease (with a slight progressive reduction in tumor volume), whereas F‐DOPA PET revealed a significant decrease in tracer uptake starting from the third month, which was confirmed at 6 months, corresponding to a partial response according to PET Response Assessment in Neuro‐Oncology 1.0 criteria. This is the first report of an IDH ‐mutant grade 2 glioma patient achieving early seizure control and metabolic response on F‐DOPA PET after vorasidenib. It highlights the potential of vorasidenib for seizure management and the value of F‐DOPA PET for early treatment assessment. Further studies are required to evaluate long‐term seizure control and potential reduction of ASM in IDH ‐mutant low‐grade gliomas treated with vorasidenib.