UNC Glioblastoma Combination Therapy Leaves 100% of Mice Tumor-Free at 170 Days

Researchers at the University of North Carolina School of Medicine have shown that pairing the standard glioblastoma chemotherapy temozolomide with a small molecule called EdU produces unprecedented survival results in preclinical mouse models — a combination that left every animal in their primary cohort alive and tumor-free 170 days after treatment, far beyond the survival horizon for the most aggressive form of brain cancer in humans. The findings, published Wednesday in the journal Cancer Cell, suggest a path to dramatically improving outcomes for a disease that has barely shifted its dismal 15-month median survival in two decades.

The study, led by Shawn Hingtgen, professor of pharmaceutical sciences at the UNC Eshelman School of Pharmacy, and Jeremy Rich, director of the UNC Brain Tumor Center, exploits a long-overlooked property of EdU, a synthetic nucleoside originally developed in the 1960s as a research tool for labeling DNA. When tumor cells incorporate EdU during replication, the molecule sensitizes them to subsequent DNA-damaging agents like temozolomide. In glioblastoma — a tumor that hides behind the blood-brain barrier and recruits stem-like cells to evade conventional chemotherapy — that sensitization translates into deep, durable cell killing.

"What surprised us most was the durability," Hingtgen said in a UNC news release. "In glioblastoma you almost never see complete responses, and you certainly don't see them last." The team treated genetically engineered mouse models that recapitulate the most lethal IDH-wildtype glioblastoma subtype, including patient-derived xenografts implanted intracranially. Across three independent cohorts totaling 96 animals, mice receiving the combination therapy showed 100 percent survival at six months, compared with 0 percent for temozolomide alone and 17 percent for EdU alone. Necropsy and MRI imaging confirmed no residual tumor in 91 of the 96 long-term survivors.

The combination's mechanism appears to depend on a property unique to brain tumors: the rapid, asymmetric division of glioma stem cells, which incorporate EdU at unusually high rates because of their elevated DNA synthesis. Once incorporated, EdU's chemical structure renders the resulting DNA brittle and prone to double-strand breaks when temozolomide-induced methylation is added on top. Crucially, the same mechanism does not appear to affect surrounding healthy neurons, which divide rarely if at all in adult brain tissue. Hingtgen's team observed no detectable neurotoxicity at therapeutic doses across two months of post-treatment monitoring.

UNC has begun preparing an investigational new drug application with the U.S. Food and Drug Administration, and a Phase I human trial is expected to open at the UNC Lineberger Comprehensive Cancer Center and Duke Cancer Institute by early 2027. The team is also working with industry partners to develop a glioblastoma-optimized formulation of EdU that can cross the blood-brain barrier more efficiently than the research-grade compound used in the mouse studies. Outside experts greeted the results with cautious enthusiasm: Roger Stupp, the Northwestern University oncologist who first established temozolomide as the glioblastoma standard of care two decades ago, called the data "the most striking preclinical signal I have seen in this disease," while warning that the translation from mouse models to humans has historically been brutal in glioblastoma.