Vorasidenib Guided by AGX PET in Recurrent/Low-grade Glioma

The goal of this prospective, single-arm, open-label clinical trial is to evaluate whether 18F-AGX PET imaging can be used to assess early treatment response and metabolic changes in adult patients with recurrent or residual WHO 2021 grade 2-3 IDH-mutant diffuse glioma receiving Vorasidenib therapy. IDH-mutant diffuse gliomas often show slow tumor growth, making early treatment response difficult to evaluate using conventional structural imaging such as magnetic resonance imaging (MRI). Clinical endpoints such as progression-free survival (PFS) and overall survival (OS) typically require long follow-up periods to detect treatment effects. Therefore, the development of sensitive and noninvasive imaging methods for early evaluation of therapeutic response is needed. This study aims to determine whether metabolic changes detected by 18F-AGX PET during Vorasidenib treatment are associated with tumor structural changes and clinical outcomes. The main questions it aims to answer are: * Whether early changes in tumor metabolic activity measured by 18F-AGX PET, including percentage change in maximum tumor-to-background ratio (TBRmax), are associated with changes in tumor growth rate (TGR) measured by MRI during treatment. * Whether early metabolic response detected by 18F-AGX PET imaging after initiation of Vorasidenib treatment can predict subsequent disease progression or tumor growth dynamics. Participants enrolled in this study will receive oral Vorasidenib once daily for 12 treatment cycles (28 days per cycle), with dosing based on body weight. Participants will: * Undergo baseline MRI and 18F-AGX PET imaging following surgery for recurrent or residual disease. * Receive oral Vorasidenib continuously for 12 cycles. * Undergo MRI scans at baseline and during treatment cycles 1, 2, 3, 6, 9, and 12 to assess structural tumor changes. * Undergo 18F-AGX PET/CT scans at baseline and during treatment cycles 1, 2, 3, 6, and 12 to assess metabolic tumor activity. * Provi