Jelly bean continues defying expectations. The 5-year-old Labrador retriever mix jumps up and down from her favorite spot on the couch and paces around the living room with such ease that it looks like she’s never had metastatic cancer. Her owners, Patricia and Zach Mendonca, still can’t quite believe the miracle. “She has a little more jerk to her gait,” says Patricia.
Jellybean was diagnosed with bone cancer in her back leg nearly three years ago. Despite amputation and chemotherapy, the cancer cells quickly spread through her blood to her lungs, as they do in 90 percent of cases in dogs. The 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 in the US. Jellybean received a trio of pills for free that the Mendoncas put in her favorite chicken-flavored treats every day. By Christmas, Jellybean’s tumors began to shrink and have not returned since. The reaction surprised even the vets who treated Jellybean and raised hopes that these drugs could help not only other dogs, but humans as well.
Jellybean’s bone cancer, osteosarcoma, also affects people, especially children and teens. Fortunately, it’s 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 treatments available aren’t very effective. Osteosarcoma patients have a survival rate of only about 30 percent if cancer cells spread to other parts of the body.
Dog studies, such as Jellybean’s trial, could change all this. Cancers that occur in 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 tissue sample from a dog and a human tissue sample from a tumor are indistinguishable. But while it’s thankfully rare in humans, osteosarcoma is at least 10 times more common in dogs, meaning there are huge numbers of canine cancer patients helping with research and drug testing. “The families and dogs that are participating 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 treats Jellybean.
Importantly, dogs are not subject to the same federal regulations that limit treatment options for humans; veterinarians are much freer to use existing drugs off-label against diseases for which there are currently no good treatments. All in all, this makes for faster and cheaper clinical trials.
Such tests are part of the Cancer Moon shot initiative that US President Joe Biden relaunched last year and for which he has asked Congress to supplement $2.8 billion in the 2024 budget. “They are designed to fill a knowledge gap that is not adequately filled by traditional studies in mice or by data that are not yet easily collected 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, which are conducted by Bosjes and 21 other veterinary universities in the US and Canada.