Jellybean continues contrary to expectations. The 5-year-old Labrador retriever mix hops up from his favorite spot on the couch and walks around the living room with ease, as if he never had metastatic cancer. His owners, Patricia and Zach Mendonca, still can’t believe the miracle. “He still has a little pull in his step,” Patricia said.
Jellybean was diagnosed with bone cancer in her back leg almost three years ago. Despite the amputation and chemotherapy, the cancer cells quickly spread through his blood to his lungs, as happens in 90 percent of cases in dogs. The survival time of this stage averages two months. “We have no hope that he will recover,” said Patricia. “We were 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 in the US. Jellybean was given three pills, free of charge, that the Mendoncas took every day of his favorite chicken flavor. By Christmas, Jellybean’s tumors had started to shrink, and they haven’t come back since. The answer surprised even the veterinarians who treated Jellybean, and raised the hope that these drugs can help not only other dogs, but also people.
Jellybean’s bone cancer, osteosarcoma, also affects humans—especially children and teenagers. Fortunately, this is relatively rare: About 26,000 new cases are diagnosed worldwide each year. The problem is that 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. Osteosarcoma patients have a survival rate of only about 30 percent if the cancer cells have spread to other parts of the body.
Canine studies, like Jellybean’s trial, could change all this. Cancers that arise in pet dogs are molecularly and microscopically similar to cancers in humans—in the case of osteosarcoma, the similarities are striking. When compared under the microscope, a smoke tissue sample and a human tissue sample of a tumor are indistinguishable. But while it’s rare in humans, osteosarcoma is at least 10 times more common in dogs — meaning there are plenty of canine cancer patients out there to help with research and drug testing. “The families and dogs that participate are an important piece of the puzzle in moving this research forward,” said Cheryl London, the veterinary oncologist at Tufts University’s Cummings School of Veterinary Medicine who treated Jellybean.
Importantly, dogs are not subject to the same federal regulations that limit treatment options for humans; Veterinarians are freer to use existing off-label drugs against diseases for which there is no good treatment. All told, this makes for faster and cheaper clinical trials.
Such tests are part of the Cancer Moonshot initiative that was relaunched by US president Joe Biden last year and for which he asked Congress to provide an additional $2.8 billion in the 2024 budget. “This is designed to fill a knowledge gap that is not adequately filled by traditional studies in mice or by data that is not yet readily available in humans,” said LeBlanc, who directs the Comparative Oncology Program. at the US National Cancer Institute. The program oversees clinical trials on dogs with cancer, conducted at Tufts and 21 other veterinary universities in the US and Canada.