Fourteen months. That’s the median life expectancy of someone diagnosed with high-grade glioma, the most common primary brain tumor in adults, even with the current standard of treatment. Providence Cancer Center researchers and a Providence Brain and Spine Institute neurosurgeon believe immunotherapy might change that statistic. They already have enrolled three patients in a trial of a new drug that relies on a genetically-modified version of a common bacterium.

The project originated in the laboratory of Providence researcher Keith Bahjat. He has worked with Listeria monocytogenes, a bacterium that in its native form can cause serious illness in individuals with compromised immune systems. Bahjat collaborated with scientists at Aduro BioTech, who have engineered a version of the Listeria bacterium for use as a cancer vaccine. The team added two cancer-specific genes to the Listeria strain, transforming a once harmful bacterium into a vaccine that has the potential to fight cancer. The vaccine can help immune cells recognize cancer cells as dangerous.

“By putting the two together, the bacteria and the tumor, we teach the immune cells that this target is bad and needs to be destroyed,” says Dr. Marka Crittenden, who is leading the trial.