Scientist are turning to a surprising chemical to treat a deadly form of brain cancer.

A team from the Northwestern University Feinberg School of Medicine and the Translational Genomics Research Institute (TGen) have turned to ultra-low dosages of arsenic as a potential treatment against glioblastoma multiforme (GBM)—the most common and aggressive type of deadly brain tumor.

“Our findings show that, for some patients, arsenic trioxide could be a powerful therapy that could extend the lives of certain glioblastoma patients by as much as three to four times the median expectation,” Harshil Dhruv, Ph.D., an assistant professor in TGen's Cancer and Cell Biology Division and one of the study's authors, said in a statement.

The researchers identified arsenic trioxide from 650 compounds that could be potentially used against glioblastoma.

After a pair of clinical studies testing the efficacy of arsenic trioxide in combination with temozolomide and radiation in treatment of GBM, they discovered a specific subtype of GBM cells were more responsive to the arsenic trioxide treatment.

“We were then able to identify these particular patients as having the same genomic signatures as those we had tentatively identified in our computer and laboratory screenings of potential therapies,” Dhruv said.

Researchers reassessed the earlier clinical trials and zeroed in on mesenchymal (MES) and proneural (PN) glioma subtypes, whose genomic signatures differ according to distinct underlying misbehaving genes.

“Arsenic trioxide was found to be the most potent compound in non-MES GBM cells,” Dr. Jonathan Bell, Ph.D., the study’s lead author, said in a statement. “We found that PN GBM patients responded better to ATO [arsenic trioxide] than any other subtypes as demonstrated by longer overall and progression-free survival.”

The researchers also identified two other benefits of using arsenic trioxide. They found it is able to penetrate the network of ultra-small capillaries—the blood-brain barrier—that surrounds the brain and spinal fluid and protects the central nervous system from most toxins and spikes in hormones. They also found that costs are minimal because arsenic is abundant in nature.

“Rather than treat all patients, we want to design a prospective clinical trial that we can enrich for those patients whose genomic signatures indicate they would be the best candidates for success," Dhruv said. “This would be a biomarker-driven, precision-medicine clinical trial for glioblastoma -- a way to match the right drug to the right patient.”

The researchers will now validate the findings by initiating a new clinical trial aimed at matching arsenic trioxide with glioblastoma patients that have a specific genomic signature.

“We sought to identify compounds that specifically disrupt the growth of different GBM molecular subtypes,” Dr. Leonidas Platanias, Ph.D., director of the Robert H. Lurie Comprehensive Cancer Center at Northwestern's Feinberg School of Medicine and the study's senior author, said in a statement.

The median survival of glioblastoma patients is only 15 months, with an estimated 17,000 succumbing to brain and other nervous system cancers annually.