“In less than 48 hours, we could see these tumours shifting from what we refer to as ‘cold’,” said Elias Sayour, a children’s cancer specialist at the University of Florida. Cold means silent. Few immune cells, hardly any response. Two days after the vaccine went in, the tumors in four people with glioblastoma had gone the other way, to what he calls “hot”.
For families facing this diagnosis, that is the kind of sentence that stops you. Glioblastoma is the most common form of brain cancer and one of the most lethal. Average survival is around 15 months, and the standard care is surgery and radiation with chemotherapy in some mix. Researchers have thrown targeted drugs and immunotherapies at it, and the tumor has mostly shrugged them off.
A vaccine built from the patient’s own tumor
The work, from Sayour’s group at UF Health, appeared in the journal Cell in May 2024. It uses mRNA, the same family of technology behind two of the approved Covid vaccines, but it is personalized. RNA was pulled from each patient’s own tumor, and the messenger RNA was amplified and wrapped in a newly designed package before being injected into the bloodstream. The aim was to make the tumor cells look to the immune system like a dangerous virus.
The package itself is the clever part. Ordinary mRNA vaccine particles have a spherical core and hold only a little cargo. Sayour’s team built a particle with layers of fat running through it, like the buttery sheets of a flaky French pastry, and sandwiched many mRNA molecules into each layer. More blueprints per particle meant more abnormal proteins to draw the immune system’s attention.
“We felt like we needed [to try] new approaches that really shock the [immune] system,” Sayour said.
What four patients can and cannot tell us
Four patients. The researchers say plainly that this is not enough to know whether the vaccine helps anyone live longer. The trial was a first-in-human test, and its main job was to show the approach was feasible and to look for signs that the immune system noticed the tumors. On both counts it largely succeeded. The immune response was strong in all four participants.
All four also had side effects. Some were serious, but in each case they were managed, Sayour said. The Independent reported that the patients lived longer than predicted, some free of disease, though it is too early to judge clinical effects. Results in 10 pet dogs with brain tumors that arose on their own pointed the same direction.
Sayour himself is careful. “We’ve only treated four patients with a few [vaccine] doses,” he warned, adding that much remains unknown. More small trials are already in the works, one of them in children with brain cancers, and 24 people are to be recruited for the next part of the current study.
Sources
- mRNA Vaccine Boosts Immune Response Against Glioblastoma (NCI Cancer Currents)
- New mRNA cancer vaccine triggers immune system to fight aggressive brain tumour (The Independent)
