The much-anticipated Vaccine Against Canine Cancer Study enrolled its first patients in May 2019. To date, 274 dogs have entered the study at the three participating sites (Colorado State University, the University of Wisconsin-Madison, and the University of California, Davis). VACCS investigators seek to recruit 800 healthy, middle-aged pet dogs to evaluate the effectiveness of the cancer prevention vaccine.

The clinical trial is led by Colorado State University’s Dr. Douglas Thamm, director of clinical research at the Flint Animal Cancer Center at the James L. Voss Veterinary Teaching Hospital.

“This is a critical study in the evaluation of this vaccine,” Thamm said.

“While effectiveness and safety have been shown in the lab, moving immediately to an expensive and time-consuming human study is a leap that is hard to justify. Testing this approach in dogs will serve as the perfect bridge to human studies. Additionally, if it is successful, we will have a new tool for cancer prevention in our pets, potentially decades before it is available for humans.”

The protocol requires visits every other week for the first four visits to receive a series of vaccinations. After that, patients will visit every six months for the remainder of the study (five years) and receive a vaccine booster once per year. Nearly half of the enrolled patients have completed the initial six-week vaccine protocol.

Even if the vaccine doesn’t turn out to be the answer, Thamm believes the team will still learn valuable information related to early detection and other relevant health data.

“While we all want the vaccine to work, the fact that we can closely follow 800 patients over five years will no doubt provide a wealth of beneficial information,” said Thamm.

Study leaders expect to have preliminary data in two to three years.

The vaccine was developed by Stephen Johnston, a professor and director of the Center for Innovations in Medicine at Arizona State University. Johnston and his team discovered a way to identify commonalities among cancerous tumors and used that information to develop what they believe is a potential one-size-fits-all cancer prevention vaccine. The study is funded by the Open Philanthropy Project.

Seeking Participants

All three sites are continuing to recruit and enroll patients. Owners must live within 150 miles of one of the participating trial sites. Other qualifications include:  dogs must be between 6 and 10 years of age, weigh at least 12 pounds, and have no history of cancer. Dogs must also be among one of 45 eligible breeds or mixed breeds. Complete qualifying information as well as an enrollment form is available online at