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• Posted May 2, 2024

MRNA Vaccine Fights Deadly Brain Tumor in Small Trial

An experimental cancer vaccine can quickly reprogram a person's immune system to attack glioblastoma, the most aggressive and lethal form of brain cancer, a small, preliminary study has found.

The cancer vaccine is based on mRNA technology similar to that used in COVID vaccines, but in this case a patient's own tumor cells are used to create a personalized vaccine, researchers said.

The vaccine teaches the immune system to see tumor cells as a dangerous virus, prompting a vigorous immune response against the cancer, researchers said.

One of the most impressive results was how quickly the injectable vaccine turns the immune system against a brain tumor, said senior researcher Dr. Elias Sayour, a pediatric oncologist with University of Florida Health who pioneered the new vaccine.

In a first-ever human clinical trial with four adult patients, the vaccine prompted a quick and apparently effective immune attack on cancer.

"In less than 48 hours, we could see these tumors shifting from what we refer to as 'cold' -- immune cold, very few immune cells, very silenced immune response -- to 'hot,' very active immune response,"Sayour said in a university news release.

"That was very surprising given how quick this happened, and what that told us is we were able to activate the early part of the immune system very rapidly against these cancers, and that's critical to unlock the later effects of the immune response,"Sayour added.

The results mirror those seen in 10 pet dogs with brain tumors who served as early test subjects, as well as lab mice. Dogs offer a natural opportunity to test brain cancer therapies because they're the only other species that regularly develops brain tumors, the researchers explained.

The vaccine now will be tested in a phase 1 pediatric clinical trial for brain cancer, researchers said.

The trial will include up to 24 adult and child patients to validate the findings of this early study.

Glioblastoma is a very deadly cancer, with an average survival of around 15 months. Currently, doctors use surgery, radiation and chemotherapy to fight the tumor.

The four patients either lived disease-free longer than expected or survived longer than expected, although it's too early to draw firm conclusions about the vaccine's effectiveness, researchers said.

The pet dogs lived an average of 139 days, compared with the typical average survival of 30 to 60 days for dogs with brain tumors.

The new study was published May 1 in the journal Cell.

The new vaccine is made specially for each patient, using genetic material extracted from their own surgically removed tumor.

The vaccine also boasts a complex delivery system that's been newly engineered to make it more effective, researchers said.

"Instead of us injecting single particles, we're injecting clusters of particles that are wrapping around each other like onions, like a bag full of onions,"Sayour said. "And the reason we've done that in the context of cancer is these clusters alert the immune system in a much more profound way than single particles would."

As a result, the vaccine generates "these really significant and rapid immune responses that we're seeing across animals and humans,"said researcher Dr. Duane Mitchell, director of the University of Florida's Brain Tumor Immunology Program.

If the vaccine proves successful, it could offer a new way to fight cancer, Sayour said.

"I am hopeful for how this could now synergize with other immunotherapies and perhaps unlock those immunotherapies,"Sayour said. "We showed in this paper that you actually can have synergy with other types of immunotherapies, so maybe now we can have a combination approach of immunotherapy."

More information

The National Cancer Institute has more about cancer treatment vaccines.

SOURCE: University of Florida, news release, May 1, 2024