Targeting of Mutant Isocitrate Dehydrogenase in Glioma: A Systematic Review

Background/Objectives: Mutant isocitrate dehydrogenase (IDH) inhibitors represent a major advance in precision oncology. The recent Food and Drug Administration approval of vorasidenib for IDH-mutant glioma highlights its therapeutic potential in this setting. As this and other mutant IDH inhibitors enter the clinical setting, providers are tasked with staying informed of the evolving therapeutic landscape as more is learned about this unique class of medications. We aimed to summarize insights from preclinical studies and clinical trials exploring their use in IDH-mutant glioma. Methods: We reviewed notable preclinical studies establishing the rationale for targeting mutant IDH. We performed a systematic review of clincaltrials.gov to identify both completed and ongoing interventional IDH-directed trials in patients with IDH-mutant glioma. Results: We identified 8 published and 15 ongoing clinical trials evaluating IDH-directed therapies. IDH inhibitors have been shown to slow and, in some cases, reverse glioma tumor growth, with activity that may extend beyond their currently approved indications. The presence of contrast enhancement is consistently a negative predictor of response for ivosidenib and vorasidenib, although safusidenib and olutasidenib preliminarily may retain efficacy in these cases. Novel approaches such as IDH-directed vaccines and combination therapy using mutant IDH inhibitors with immunotherapy are currently under active investigation. Conclusions: Mutant IDH inhibition is a promising, well-tolerated, and evolving approach for many patients with IDH-mutant glioma. Ongoing research will clarify its optimal clinical utility and potentially expand its indication.