A New Vaccine May Be Able to Reduce the Risk of Cancer in Dogs · The Wildest

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A New Vaccine May Be Able to Reduce the Risk of Cancer in Dogs

The Vaccination Against Canine Cancer Study (VACCS trial) is showing promising results. 

by Sio Hornbuckle
January 23, 2024
a dog receiving a vaccination
hobo_018 / iStock

Canine cancer is a nightmare that most pet parents would do anything to avoid. Unfortunately, it’s a reality that many pups and their guardians have to endure. According to the American Veterinary Medical Association, approximately half of all dogs over the age of 10 will develop cancer; the risk is even higher for purebred dogs. But a new vaccine is showing promising results when it comes to preventing cancer in dogs. 

A new vaccine against canine cancer 

Dr. Stephen A. Johnston, the director for the Center for Innovations in Medicine at The Biodesign Institute and a professor in the School of Life Sciences at Arizona State University, began working on a vaccine against dog cancer over a decade ago. In 2018, The Open Philanthropy Project awarded Dr. Johnston a 6.4 million dollar grant to begin putting his vaccine to the test. The Vaccination Against Canine Cancer Study (VACCS trial), a five-year study that is currently underway, is the largest ever clinical trial on canine cancer.  

The vaccine is preventative; rather than curing cancer, it aims to keep dogs cancer-free. “We believe cancer preventative vaccines have a higher expected value than curative cancer therapies, since an effective vaccine would likely be a less expensive way to provide decades of healthy life compared to current cancer therapies, which often only extend life for a few months or years,” the Open Philanthropy Project grant announcement said

The trial participants are healthy dogs who live at home and receive biannual exams. Some of the dogs receive the real vaccine, while others receive a placebo. Dogs receiving the placebo should develop cancer at typical rates; the researchers can then measure those numbers against the vaccinated pups. All dogs participating in the study, whether they receive the vaccine or not, will be given a credit toward cancer-related medical expenses. 

Promising early results

So far, “results show a reduction in the number of tumors for about 65 percent of dogs vaccinated,” Daily Paws reported. Researchers originally aimed to prevent eight types of canine cancer (mast cell tumors, osteosarcoma, lymphoma, melanoma, mammary cancer, lung cancer, soft tissue carcinomas, and hemangiosarcoma), but the results have not shown a reduction in all eight.

Mast cell tumors and adrenal tumors were reduced, but others, including hemangiosarcoma (a very common and rapidly-spreading canine cancer), were not. Dr. Johnston feels confident that they can improve results with what they have learned so far. “We now know why — we just didn’t put the right components in. So, the next version will have components for hemangiosarcoma,” Dr. Johnston told Daily Paws. 

In addition to cancer, the vaccine has reduced arthritis and other chronic diseases by over 50 percent. Dr. Johnston thinks this may be because the vaccine is triggering an immune response against senescent cells. According to Nature Reviews Drug Discovery, senescent cells contribute to many “diseases of late life, including cancer, atherosclerosis and osteoarthritis.” 

The larger implications of a new canine cancer vaccine

The vaccine still needs to gain USDA approval before becoming available to the public. Dr. Johnston is sure that, once available to the public, the vaccine will be much less expensive than non-preventative cancer treatments. “If the vaccine works it should be inexpensive enough that everyone in the world could get it,” Dr. Johnston told Arizona State University

Dr. Johnston hopes that this research will have implications for preventing human cancers as well as canine cancers. Many dog cancers are very similar to human cancers, and our immune systems respond similarly. However, dog tumors develop much more quickly than human tumors.

That means a vaccine can be tested in a much shorter amount of time — Dr. Johnston estimates that its efficacy can be measured in five years or less, while it would take 15 to 20 years to see results in humans. “If we show that [the vaccine] is successful in dogs, it’s really hard to argue why you wouldn’t try to do this in people,” Dr. Johnston told

Sio Hornbuckle

Sio Hornbuckle is a writer living in New York City with their cat, Toni Collette.

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