Scientists at Johns Hopkins University say they’ve developed a gel-based treatment that might be incredibly effective at treating an often-fatal brain cancer. In a study of mice released this week, the gel in combination with surgery was found to eradicate 100% of glioblastoma tumours. It will take more research and safety testing before we can think of trying out this method in humans, however.
Glioblastoma is the most common form of brain cancer, accounting for around half of all primary tumours. While rare overall, it’s one of the deadliest cancers. According to the National Brain Tumour Society, the five-year survival rate for diagnosed glioblastoma patients is 6.8%, while the average length of survival is only eight months. More than 13,000 Americans are expected to be diagnosed with glioblastoma annually, and over 10,000 die from it every year.
These cancers are difficult to treat for many reasons. They tend to be very aggressive and fast-growing, for one. The natural defences of the brain, including the blood-brain barrier, also make it hard for treatments to effectively reach the tumour site. And it’s often impossible to completely remove tumours surgically, given the delicate nature of the brain.
In the last few years, scientists have found novel drugs that could possibly better treat brain cancers than the current standard. But researchers at Johns Hopkins and elsewhere, led by chemical and biomolecular engineer Honggang Cui, wanted to try a different approach. They theorised that they could find an improved way to deliver existing drugs to the brain.
To do this, they converted the drug paclitaxel, an FDA-approved treatment for many cancers, into a solution that turns itself into a hydrogel once inside the brain. They then mixed in an antibody that attacks a protein called CD47. CD47 is normally found on the surface of many cells, but some cancers use CD47 to protect themselves from being eaten by immune cells called macrophages. So the antibody is intended to turn off this protection. Alone, neither drug taken as usual would have much effect on glioblastoma tumours. But the researchers envision that the gel could be delivered to the brain alongside surgery, with the gel filling up the crevices of the remaining tumour and finishing it off for good.
In their new study, published Monday in PNAS, the team detailed the results of their work with mice. Amazingly, 100% of the mice treated with surgery and the gel survived. The gel also seemed to prime their immune system and their macrophages against glioblastoma. When the researchers introduced new tumours into the surviving mice, the mice were able to fend off the cancer on their own.
Few experimental treatments show this kind of success, even in early animal testing. And given the poor track record of current options for glioblastoma, the results are certainly tantalising. But Cui and his colleagues caution that their research is still in the very early stages of development, and there are many questions left to be answered — including whether their gel will behave the same way it does in a human brain that has glioblastoma as it seems to in a mouse brain.
“Mice have very tiny brains, but we still have to figure out if this can safely work with larger human brains,” Cui told Gizmodo by phone.
For now, human clinical research is still a bit away. The team next plans to test out their method in other animal models.