Ontario Vet College cancer treatment breakthrough spurs human clinical trials

A cancer treatment breakthrough that worked for mice and cats and was developed by researchers at the Ontario Veterinary College is now getting human trials.

"It's revolutionized the way we conduct the research in mice," pathobiology professor Byram Bridle said. "We've gone from cancers we could not ever cure to being able to cure them using this strategy."

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The key to the treatment is injecting oncolytic viruses viruses that target cancer cells into a patient's veins and the virus makes its way to the spleen, an organ that filters blood. It turns out, the spleen is a unique spot in the body which is the perfect location for a second booster vaccine.

"We found this location in the spleen where the memory cells are separated from the killer cells, and this is very, very important," Bridle said.

Faster, 'unprecedented' response

Usually when people are given vaccines with a booster shot, the booster has to wait until the immune response to the vaccine is past its peak because the booster may fight with the original vaccine.

But by being able to target the memory cells in the spleen, the cancer-fighting virus can be injected as a booster at that peak time to amp up the fight by the vaccine, which creates an "unprecedented" immune response. Bridle said.

So faster and much higher magnitude response, and that's the key when you're battling something like cancer.- Byram Bridle, Ontario Veterinary College researcher

This new therapy not only keeps the pressure on the cancer cells, it increases the attack on them to take them down when the cancer cells are weak, he said.

"So faster and much higher magnitude response, and that's the key when you're battling something like cancer where it's a race against time. You have cancer growing, the number of targets are ever increasing, so the faster that we can get that killer response amplified, the better we're able to control that cancer growth," he said.

Human clinical trials have started

Bridle has already used the treatment on mice and cats with great results and the findings were published in the Journal of Immunology in April. How these animals get cancer is very similar to humans.

Now, researchers from Ottawa, Hamilton and Toronto have started clinical trials in people.

Bridle said often the cancer that kills people are those cells that migrate in the body to other areas where they go undetected.

By putting the vaccine in intravenously, "if there's any tumour cells throughout the body, the idea is that it can find them and infect them and kill them. We don't even need to know where they are."

He said the treatment could potentially be used to fight any cancer as well as other serious infectious diseases, such as dengue fever or Ebola, where you want a maximum immune response as quickly as possible.