Your dog is a secret weapon in the fight against cancer

jellybean continues defy expectations. The 5-year-old Labrador retriever mix jumps up and down his favorite spot on the couch and walks around the living room with such ease that it’s as if he never had metastatic cancer. Its owners, Patricia and Zach Mendonca, still can’t believe the miracle. “She has a little more kick to her step,” says Patricia.

Jellybean was diagnosed with bone cancer in her hind leg almost three years ago. Despite the amputation and chemotherapy, the cancer cells spread rapidly through his blood to his lungs, as they do in 90 percent of cases in dogs. Survival time at this stage averages two months. “We had no hope of curing her,” says Patricia. “We were pretty devastated.”

So, in November 2020, the Mendoncas enrolled Jellybean in a clinical trial at Tufts University, about an hour’s drive from their home in Rhode Island, USA. Jellybean was given a trio of pills, free of charge, that the mendoncas put daily in their favorite candies flavored with chicken. By Christmas, Jellybean’s tumors had begun to shrink and have not returned since. The response surprised even veterinarians treating Jellybean and raised hopes that these drugs could help not only other dogs, but humans as well.

Jellybean bone cancer, osteosarcoma, also affects people, especially children and adolescents. Fortunately, it is relatively rare: about 26,000 new cases are diagnosed worldwide each year. The problem is, there haven’t been any new treatments for more than 35 years, says veterinary oncologist Amy LeBlanc, and the ones that are available aren’t very effective. Patients with osteosarcoma have a survival rate of only about 30 percent if cancer cells spread to other parts of the body.

Canine studies, like the Jellybean trial, could change all this. Cancers that arise in domestic dogs are molecularly and microscopically similar to cancers in people; in the case of osteosarcoma, the similarities are striking. When compared under the microscope, a canine tissue sample and a human tissue sample from a tumor are indistinguishable. But while thankfully rare in humans, osteosarcoma is at least 10 times more common in dogs, which means there are plenty of canine cancer patients to help with research and drug testing. “The families and dogs involved are an important piece of the puzzle in moving this research forward,” says Cheryl London, a veterinary oncologist at Tufts University Cummings School of Veterinary Medicine who is treating Jellybean.

It is important to note that dogs are not subject to the same federal regulations that limit treatment options for humans; veterinarians have much more freedom to use existing off-label drugs against diseases for which there are currently no good treatments. Altogether, this makes clinical trials faster and cheaper.

Such judgments are part of the Cancer Moon Launch initiative that US President Joe Biden relaunched last year and for which he has asked Congress to provide a $2.8 billion in the 2024 budget. “They are designed to fill a knowledge gap that is not sufficiently covered by traditional mouse studies or by data that cannot yet be easily collected in humans,” says LeBlanc, who directs the Comparative Oncology Program at the US National Cancer Institute. The program oversees clinical trials in dogs with cancer, conducted by Tufts and 21 other veterinary colleges in the US and Canada.


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