Researchers have demonstrated in mice a new approach for delivering medication across the blood-brain barrier to treat tumors that cause aggressive, lethal brain cancer.

In a new study, the researchers show how a modified peptide, in mice, helps a cancer drug pass through the blood-brain barrier, which is known to be extremely difficult to penetrate and thus serves as a massive hindrance to treating brain tumors. The study was published online in the Journal of Controlled Release.

“We were not only able to get a drug into the brain, but to deliver it at a concentration that should be able to kill tumor cells,” says Sean Lawler, PhD, the senior author and an associate professor of pathology and laboratory medicine.

Brain malignancies are some of the most lethal forms of cancer, as well as the hardest to treat. Glioblastoma is the most common malignant brain cancer—it’s highly aggressive, and most patients live for only around 15 months after diagnosis. Lawler says there has been frustratingly little progress in treating glioblastoma and improving the chances of survival over the past 20 years.

“We think this is a significant finding that could ultimately inform new approaches to treating people who face some of the most severe brain cancer diagnoses,” he says.

The blood-brain barrier protects the brain from harmful substances—but when it comes to anti-cancer drugs, it does its job almost too well: they can’t penetrate the barrier in sufficient amounts to have a therapeutic effect on tumors.

The researchers modified a type of peptide that has an intrinsic ability to cross membranes and penetrate tissues. “We had this enhanced peptide that was not only better at getting through the blood-brain barrier, but could also last longer in the body,” Lawler says. “And then we were able to hook it up to a cancer drug and test it in mouse models of glioblastoma. That was our major step forward.”

Then, using mice with brain tumors, the team assessed the concentration of drugs needed to kill the tumor cells, as well as to understand how to deliver the drug in a way that would not harm the murine patients. According to the study, the survival rate of the mice treated with the enhanced peptide increased by 50 percent.

“This is only the first attempt,” Lawler says. “We think that with some further optimization and tweaking of the drug and the delivery system, we should be able to improve the treatment, and the survival rate, quite significantly.”