Biotherapy research at the OVC receives national attention
Dr. Byram Bridle, a pathobiology professor at the Ontario Veterinary College, has made a breakthrough in cancer treatment by working on a synergistic biotherapy approach to treat cancer in companion animals.
Emerging cancer biotherapies, including cancer vaccines, are designed to educate human immune systems to recognize targets on cancer and evoke an autoimmune response against the cancer and prevent it from coming back.
Generally, vaccines are given in booster shots. To avoid destruction of the first booster shot, one has to wait for substantial interval of time spanning weeks to months for immune response to wane and then inject the second shot. Time waited for the immune response to wane could lead to the resurfacing of the tumour.
Bridle explains that the time interval for administering second vaccine could be dramatically decreased. If the booster oncolytic (cancer killing) virus vaccine is injected intravenously (into the vein) instead of the usual intramuscular procedure, it could generate a much higher overall immune response than using the traditional vaccine method.
This breakthrough research is being developed by the combined efforts of three key research teams working at the University of Guelph, McMaster University, and the Ottawa Hospital Research Institute, and has led to Phase I human clinical trials starting in Toronto, Hamilton, and Ottawa.
“As cancer is fatal and grows rapidly, we are racing with time, and this is a big breakthrough in treating cancer and also a breakthrough because oncolytic virus finds cancer potentially anywhere in the body,” said Bridle in an interview with The Ontarion.
Explaining the therapeutic approach they use to target cancer, Bridle said, “We use two therapeutic approaches: in the first, we try and get the patient’s own immune system to recognize the targets and kill their own tumour; and the second one is the oncolytic virus that takes advantage of defects cancer cells have.”
Upon viral infection, normal cells sends out antiviral alert chemical signals to neighbouring cells and immune system and kills itself to stop virus growth within them, but tumour cells lack cell death property and become the reservoirs of oncolytic viruses. The oncolytic vaccine carrying targets in its genome expresses more target protein, thereby drawing maximum immune response to the cancer region and helping the immune system to clear its own tumour.
Bridle and his team discovered that they were are able to deliver virus to the spleen (an organ that filters blood) when injected intravenously. Since the spleen is a region where only memory cells of the immune system reside—and not the killer cells—they could escape the battle of the peak immune response.
“[For the] first time ever, we can actually deliver the vaccine at the peak of its primary response. This physical separation of this location is what we are trying to target, and as a consequence, we are able to reap the benefit of [the] second booster vaccine immediately.”
In Canada, pediatric oncology patients are given multicolour bravery beads. Each beads represents a procedure that they have undergone as part of cancer treatment. Many children treated for cancer will have necklaces with several hundreds of beads by the time they complete the entire treatment.
“Pediatric cancer patients are important examples as why many of us are interested in fundamentally new cancer therapy. That’s one of the reason why people are open to this new technology,” said Bridle.
“I dream of a future where instead of successful cancer therapy for pediatric oncology patients being represented by 100s of bravery beads I dream of successful cancer therapy represented by bracelet with only couple of beads.”
When asked if this present discovery could be used for treating other diseases, Bridle explained, “We now realize that this is very effective tool for rapidly inducing maximal immune response against any potential target antigens. We see a lot of potential in other areas, particularly very dangerous life-threatening infectious things like the Ebola virus, for example.”
Following the cat trials funded by the University of Guelph, Bridle’s research group are now getting ready to start a number of dog trials at the OVC targeting three types of cancer: osteosarcoma (bone cancer), melanoma (skin cancer), and lymphoma.
Photo by Sushma G. Puttaswamaiah.