Vaccine Shows Promise in Treating Aggressive Brain Cancer, in People and Dogs

Vaccines are an emerging cancer treatment option that uses the immune system to help fight tumors. They can include cancer cell components and may involve removing some of a patients’ immune cells to see how they react. There aren’t many approved for usage just yet, but a recent small trial shows they may be a promising option for patients with especially deadly brain tumors.

Researchers at the University of Florida recently conducted a vaccine trial with four adults with glioblastoma, a form of brain cancer with a poor prognosis. Even with surgery, chemo, and radiation options, the median survival time after diagnosis is only 15 months.

To see if these patients may have other options to prolong their lives, the Florida researchers have been working on mRNA vaccines to treat these brain tumors for seven years. The vaccines use RNA from a patient’s own tumor to build a personalized dose with amplified messenger RNA. It’s wrapped into a new delivery method with biocompatible lipid nanoparticles that makes them appear dangerous to the immune system. These sorts of treatments help teach the immune system that the tumor is foreign and needs to be fought.

According to the trial’s findings, published in Cell, promising results came fairly quickly.

Dr. Elias Sayour, senior author and UF Health pediatric oncologist who helped develop the new vaccine, explains, “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. 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.”

Though it was a small trial and it’s still too early to say how effective this treatment may be, the four participants either had a longer disease-free time than expected or lived longer than expected.

The findings mirror that of a past study in mice, as well as a trial with 10 pet dogs who had developed brain tumors. In the second study, the pups’ median survival time was 139 days, compared with 30 to 60 days for the average dog diagnosed with this form of cancer.

Dr. Duane Mitchell, study co-author and director of the UF Brain Tumor Immunotherapy Program, says, “The demonstration that making an mRNA cancer vaccine in this fashion generates similar and strong responses across mice, pet dogs that have developed cancer spontaneously and human patients with brain cancer is a really important finding, because oftentimes we don’t know how well the preclinical studies in animals are going to translate into similar responses in patients. And while mRNA vaccines and therapeutics are certainly a hot topic since the COVID pandemic, this is a novel and unique way of delivering the mRNA to generate these really significant and rapid immune responses that we’re seeing across animals and humans.”

One concern the team has is how to use the immune system in cancer treatments without spurring too many side effects. As they work on that and figure out the right dosage, the next step is a clinical trial with up to 24 adult and pediatric glioblastoma patients. From there, they hope to do a pediatric trial with 25 patients.

Their research is supported in part by the U.S. Food and Drug Administration.