Amputation and traditional chemotherapy did not stop the insidious progression of the disease towards his chest. Typically, dogs with bone cancer only live eight to ten weeks once the cancer has spread to their lungs, even with treatment. It is estimated that 15,000 dogs a year are diagnosed with bone cancer.
Determined not to give up, Patti and Zachary Mendonca enrolled their beloved pet in a trial at Cummings that explored different drug combinations for dogs with advanced osteosarcoma, the type of cancer Jellybean had.
“You can’t give up,” said Zachary Mendonca. “Life is full of hurdles, obstacles and inconveniences. But if there is any hope…you have to go for it.
Jellybean’s treatments began in November 2020, and by late December the tumors on his chest began to shrink. By February, they had disappeared. She is still taking the experimental drug.
Now, researchers are digging deeper to understand how Jellybean’s extraordinary remission may prove helpful for people, especially children, who develop similar bone cancer.
None of the others 50 dogs in the trial stayed in remission almost as long as Jellybean. They have all since died. Their median survival time was about five months, compared to two to three months for dogs receiving traditional chemotherapy.
“When we better understand why some dogs [like Jellybean] are doing well and others are not, this will allow us to layer additional treatments to improve the response we have seen,” said Dr Cheryl London, associate dean for research and higher education at the Cummings School, who oversees clinical trials.
Unlike mice and other rodents typically used in research, dogs live in our same environment. And their immune system is similar to that of humans.
“So it’s good to use dogs as a model system to ask and answer questions about treatment approaches that may have human value,” London said.
Dogs are diagnosed with many of the same or very similar cancers found in humans, including breast, bladder, and bone cancer, as well as lymphoma. And, as with humans, researchers are increasingly researching or designing drugs that can stimulate a dog’s immune system to recognize and attack cancer cells, rather than using chemotherapy, which often does havoc on many healthy cells.
“Chemotherapy is like taking a fire hose to water a houseplant; it attacks all fast-growing cells and in areas other than the tumor,” said Dr. Laura Venner, an oncology intern at Tufts who is working on the bone cancer trial.
Immunotherapy is much more targeted. The drugs are designed to wake up a patient’s immune system and teach it to specifically recognize and destroy cancer cells, while leaving other cells intact.
The trial in which Jellybean used a combination of three drugs, including a blood pressure drug used in humans that showed anticancer properties and an experimental drug, not yet approved for people or pets, which is being studied in diabetes trials.
For more than two years now, the Mendoncas have been driving more than an hour each month from their North Kingstown, RI, home of the Cummings School in Grafton, so researchers can monitor Jellybean’s progress and take X-rays and samples. of blood.
About a year ago, researchers launched a new trial. Instead of enrolling dogs like Jellybean, who had had amputations and then failed chemotherapy, they are now enrolling dogs with bone cancers that have not yet spread and giving them the three-drug combination. for two weeks before the amputation.
“Doing this before the tumor is removed is probably very important in reconditioning the immune system” to recognize cancer cells, London said.
Then the dogs stay on the meds. But for how long ?
“That’s the question of the day,” London said. “At first we were like, ‘Oh, we’ll stop at six months. And then the dogs, some of the dogs, kept going. So we were like, ‘Oh, we’ll stop at a year. And now , we’re like, “We’re not stopping.”
At the same time, scientists across the country are studying other immunotherapy approaches to bring cancer treatments from dogs to humans.
Dr. Nicola Mason, professor of medicine at the University of Pennsylvania School of Veterinary Medicine, uses listeria, a bacteria often associated with food poisoning, in his research on dogs.
“We learned that listeria is really good at waking up the immune system,” she said.
Researchers have genetically engineered listeria into a weakened form that won’t make patients sick. Next, they identified a protein associated with bone cancer and added it to the weakened listeria.
When this immunotherapy enters a patient’s body, it wakes up the immune system and tricks it into believing that the cancerous protein is listeria that it has to fight, and it attacks the cancer in the patient’s body.
Researchers only work with dogs that have been diagnosed with cancer and whose owners consent to treatments.
The knowledge gained by Mason and other researchers is now being used in a listeria trial involving children and young adults with bone cancer.
Similar to the listeria treatment, the three-drug therapy still given to Jellybean produced few side effects other than turning his once black and tan fur to predominantly gray. She eagerly chugs the pills, wrapped in treats, morning and night.
“If we miss her by a minute, she’s on top of me,” Zachary Mendonca said.
When Jellybean was first diagnosed in 2020, COVID-19 closures meant families weren’t allowed into hospitals to say goodbye to people or pets. Given the grim prognosis for Jellybean at the time, the Mendoncas feared the worst.
“I saw a lot of people saying goodbye on the phone” at the Rhode Island hospital where Jellybean was initially treated, Patti Mendonca said.
Then, when they entered Jellybean into the Tufts trial this fall, the Mendoncas realized his chances of survival were limited.
“At the time, we were just thinking, maybe she’ll just help another dog for the future,” Patti Mendonca said.
Suzanne Kreiter/Globe Staff
Now, researchers believe Jellybean’s amazing odyssey holds important clues.
“Jellybean continues to exceed our expectations and remains cancer-free after her check-up appointment in December,” said Tufts lead researcher London. “We are delighted that her success continues, and we will continue to monitor her and use what we learn from her response to the trial to inform future treatments.”
The translation of Zachary Mendonca?
“I don’t think I can go to Vegas,” he said, “because all my luck is tied to this dog.”
Kay Lazar can be reached at kay.lazar@globe.com Follow her on Twitter @GlobeKayLazar.
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