Triple therapy reduces tumor burden and improves survival in glioblastoma models

A new research paper was published in Oncotarget, Volume 16, on March 27, 2025, titled "Imipridones ONC201/ONC206 + RT/TMZ triple (IRT) therapy reduces intracranial tumor burden, prolongs survival in orthotopic IDH-WT GBM mouse model, and suppresses MGMT."

Researchers from Brown University, led by first author Lanlan Zhou and corresponding author Wafik S. El-Deiry, have shown that combining a new class of drugs called imipridones with standard glioblastoma treatments significantly improves outcomes in mice. The study tested ONC201 and its analog ONC206 in combination with radiation therapy and the chemotherapy drug temozolomide (TMZ), a regimen referred to as IRT. This triple therapy slowed tumor growth and extended survival in a mouse model of glioblastoma, offering a potential new strategy for one of the most aggressive and treatment-resistant brain cancers.

Glioblastoma is a fast-growing brain tumor with a poor prognosis and limited treatment options. Standard care typically includes surgery, radiation, and TMZ, but most patients still face a short life expectancy. While ONC201 and ONC206 are currently being studied in clinical trials as single agents, there has been limited information on how they interact with standard therapies. This study is the first to show that both drugs work synergistically with radiation and TMZ, strengthening their overall effects.

The results showed that in both laboratory-grown tumor cells and mice, the triple therapy significantly slowed cancer cell growth, reduced tumor size, and prolonged survival compared to using any single or double treatment. Mice treated with IRT lived an average of 123 days, with some surviving more than 200 days-far longer than the 44 to 103 days observed with other treatment combinations. In addition to directly killing tumor cells, ONC201 and ONC206 lowered the expression of MGMT, a protein that helps tumors resist chemotherapy, making the treatment more effective.

The researchers also found that the triple therapy reshaped the tumor environment. It decreased levels of harmful molecules that promote tumor growth and immune evasion while increasing signals that activate the immune system. This dual action-directly attacking tumors and boosting immune responses-adds to the potential impact of this treatment approach.

"Overall, our preclinical findings support further exploration of the ONC201 and ONC206 IRT regimen as a potential treatment for GBM and diffuse gliomas with H3K27M mutations."

While these findings are based on preclinical mouse models, they offer strong support for advancing this triple therapy to clinical trials. ONC201 and ONC206 are promising due to their ability to cross the blood-brain barrier and enhance the effects of standard treatment. This combination could lead to more effective therapies for glioblastoma and other hard-to-treat brain tumors.