This week, a 9-year old Gordon setter named Trilly became the first dog in the nation to receive an experimental injection that could potentially prevent many types of cancer that dogs encounter. As part of a study involving 800 other dogs, Trilly may be a part of groundbreaking history for both canines and people, as the same vaccination could possibly be used for humans one day.
The study included three veterinary centers across the United States, including the UW School of Veterinary Medicine, where Trilly was treated, making it the largest clinical trial of veterinary medicine in history. Undoubtedly, taking on finding and testing a way to prevent (but not cure, since this is a vaccine) cancer would require and deserve a monumental effort. And for many reasons, dogs are a perfect group to pursue such a treatment for, as it’s expected that nearly 50 percent of all dogs 10 years and older are expected to develop some kind of cancer in their life, making them more susceptible to its different diseases than even humans. It’s the number one killer of aging dogs and would also be the top killer of aging humans if it weren’t for heart disease.
The vaccine was originally created by Stephen Johnston, a professor at Arizona State University and director of the Center for Innovation in Medicine. It is theorized to work by training the immune system to recognize a group of unusual proteins that are common across many types of cancer, giving the body a chance to fight the disease off and destroy any cancerous cells. If this trial with Trilly is successful, a company by the name of Calviri Inc, which Johnston owns, is expected to develop the vaccine for humans. According to Johnston himself, Calviri Inc. has the technology to make that human vaccine now, but it would take at least five to 10 years for that to be ready. Again, all of this is dependent on whether or not Trilly’s trial is a success.
“I don’t know if this is going to work, and I don’t know what the odds are. It could be 10%, it could be zero percent,” said Johnston, a graduate of UW-Madison where Trilly was injected with the experimental vaccine. “But I would say that, if it did work in a dog, it will probably work in people. I would almost count on it.”
Currently, there are known vaccines for cancer, but they are developed to protect against specific types of the disease and very difficult to access, costing upwards of $100,000. Johnston’s vaccine is designed to protect against a number of different forms of the disease as well as being affordable enough for access and treatment in impoverished parts of the world.
Next up, a randomized selection of the 800 dogs in Trilly’s study will be selected to receive the same treatment will the other half will be receiving a placebo. About 280 of the dogs in the study will be treated at UW-Madison along with Trilly. All of the dogs are currently cancer-free and between the ages of six and 10, and their results will be examined to see if the vaccine results in lower instances of cancer.
In fact, one interesting factor in Trilly’s case is that there’s a chance she may have actually received the placebo and not the true vaccine. Over a six week period she’ll be receiving three more shots to complete the initial administering period, but not even the researchers giving her injections know if she’s been given a placebo or the vaccine itself as she gets cancer screenings throughout the study.
“This vaccine is essentially putting out wanted posters to the immune system saying, ‘When you start seeing those cells, go ahead and kill them,’” said UW Veterinary Care oncologist David Vail. According to Vail, the vaccine will train the dog’s immune system to recognize and attend to cancerous cells even before an MRI can. Johnston worked for 12 years to identify 30 different abnormal proteins that are present in different types of cancerous tumors. His vaccine introduces those 30 proteins to the recipient by injecting them into the body and allows the immune system to recognize them before they could naturally come back as cancerous cells in the future. According to Johnston, a given tumor has about a 95 percent chance of carrying 50 percent of those proteins. He says that should be enough for the immune system to build up a memory of those abnormal proteins and equip itself to destroy them. The interesting part is that the type of cancer isn’t dependent on whether or not it’s been familiarized through the vaccine. Vail says this strategy of preventing multiple types of cancer is a “paradigm shift” in how researchers approach fighting it.
As much optimism as Johnston’s creation can instill in us, his vaccine has its doubters. Johnston says his method sidesteps the common teaching in the cancer research field that tumors are individualized to each person. In the past, vaccines have been created to target specific mutations in the DNA of cancerous tumors.
“Everybody assumed that the important mutations were occurring at the DNA level,” Johnston said. “They didn’t look under the right lamppost.”
He explains that the vaccine may not necessarily work in identifying and attacking cancerous cells, with tumors “tricking” the immune system into thinking there are healthy cells present when in fact there are cancerous ones. But even if the vaccine doesn’t work in preventing a tumor from developing, he says it should prevent cancer from spreading, which is ultimately how cancer tends to kill its victims.
In dogs, the most common types of cancer are mast cell tumors, which are a form of skin cancer, melanoma, which is the most common malignant tumor of a dog’s mouth, lymphoma, which is a cancer of a type of blood cell, bone cancer, or Osteosarcoma, which can affect any type of dog, and Hemangiosarcoma, which can spread very fast anywhere in the body.