Validation of the Diagnostic and Predictive Tool, D2HGlo, for the Quantification of the Oncometabolite D-2-Hydroxyglutarate (D-2-HG) in Glioma

About This Grant

Summary This proposal describes a collaborative effort between Northern Michigan University (NMU), Johns Hopkins University (JHU), and the F.M. Kirby Research Center for Functional Brain Imaging at the Kennedy Kreiger Institute for the analytical and clinical validation of the novel, genetically encoded FRET-based probe, D2HGlo. The intended use for this diagnostic and predictive tool includes preoperative and post-operative characterization of mutant IDH (isocitrate dehydrogenase) glioma through detection of the surrogate biomarker and oncometabolite, D-2-hydroxyglutarate (D-2-HG), which is the product of the mutant IDH enzyme. D2HGlo has the potential to modify current mutant IDH glioma treatment modalities as this diagnostic tool is anticipated to predict patient response to therapeutic strategies months earlier than standard MRI analysis of disease progression. The 2021 World Health Organization (WHO) classification of central nervous system (CNS) tumors identifies mutant IDH gliomas as a biologically and clinically distinct group, adding emphasis on the development of an assay to characterize this category of tumors. The absence of an assay utilizing a liquid biomarker has been a significant hurdle for diagnostic and prognostic care of mutant IDH glioma patients and this shortcoming can be remedied as D2HGlo specifically detects D-2-HG from non-invasive clinical specimens. Here, we propose to characterize the first liquid biomarker assay allowing for the specific, inexpensive, and non-invasive detection of D-2-HG in urine, serum, and plasma, as well as cerebrospinal fluid. Of significance to this proposal is the success of the mutant IDH inhibitor, vorasidenib, a mutant IDH 1/2 inhibitor. A phase III clinical trial for this therapeutic agent recently (September, 2023) demonstrated clinical utility by maintaining disease stability and providing a delay in the need for additional therapeutic interventions. The success of vorasidenib caused the trial to be halted permitting patients from the placebo group to be placed on the therapy as well. With few side effects identified, the scientific and healthcare communities expect FDA approval of vorasidenib and its use in treating patients with mutant IDH glioma. With the significant advent of this mutant IDH therapy, D2HGlo is perfectly positioned to address the clinical laboratory need for a liquid biomarker assay to determine if and when a patient is failing therapy. By monitoring D-2-HG production in patients with mutant IDH glioma utilizing D2HGlo, cycles of chemotherapy are more likely to be attenuated, resulting in both physical and fiscal relief to the patient. In addition, D2HGlo is highly amenable for implementation in locations where treatment resources are limited, thereby increasing patient access to needed healthcare. This proposal offers validation of a fluid-based test for D-2-HG and has the potential to become a cost-effective integrated biomarker to predict tumor treatment response and tumor recurrence, thereby guiding clinical decision-making beyond that achievable using current imaging tools. In summary, validation of D2HGlo has the potential to drastically transform current mutant IDH glioma treatment regimens while significantly reducing the financial and physical burdens of the disease.