A groundbreaking experimental cancer vaccine developed by researchers at Yale University is showing remarkable success in canine clinical trials, potentially transforming treatment options for dogs diagnosed with aggressive and typically fatal cancers.
The vaccine, created by Dr. Mark Mamula at Yale, is currently being tested at 11 sites across the United States and one in Canada. Among the success stories are Lola, a 9-year-old golden retriever who overcame metastatic oral melanoma, and Rainier, an Akita who survived both bone cancer and lung metastasis.
Lola's Journey: From Terminal Diagnosis to Cancer-Free
In February 2023, Lola was diagnosed with oral melanoma that had already metastasized to her lungs. Her owner, Allison Roth, was initially told that Lola had less than six months to live.
"When Lola was a puppy, I was treated for a brain tumor at the Mayo Clinic," said Roth. "Through my multiple brain surgeries, she was always by my side. When it came time for her cancer treatments, I was thrilled that she would be treated at UC Davis – what I would call the 'Mayo Clinic for dogs.'"
Faced with limited options, Roth enrolled Lola in a clinical trial at UC Davis' Veterinary Center for Clinical Trials. The study, "Intravenous Doxorubicin and Inhaled IL-15 Immunotherapy for Treatment of Lung Metastases," was investigating a novel immunotherapy approach for treating lung metastases.
Dr. Robert Rebhun, co-principal investigator of the study, explained: "The previous trials we conducted found that inhaled IL-15 is well tolerated and resulted in durable responses in a subset of dogs with metastatic melanoma or osteosarcoma. We were excited to see if modulating the immune system with chemotherapy might improve response rates in patients with metastatic tumors to the lung."
Lola's initial response to the treatment was discouraging. She did not tolerate the chemotherapy well, and subsequent X-rays showed tumor growth rather than regression. After failing the trial twice, Roth opted for palliative radiation treatments.
In a surprising turn of events, an X-ray in September 2023 revealed that all of Lola's tumors had disappeared. Researchers believe she experienced "pseudoprogression," a phenomenon where tumors appear larger due to inflammation before eventually shrinking in response to immunotherapy.
Two years after her initial diagnosis, Lola remains cancer-free with no recurrence of tumors.
Rainier's Story: Beating the Odds Twice
Kasey Bentz's Akita, Rainier, was diagnosed with bone cancer in 2023, just before his 10th birthday. The prognosis was grim, with veterinarians estimating he had only about two months to live.
"The urgent care told us that we should anticipate about two months of time with him," Bentz recalled.
Refusing to give up, Bentz consulted an oncologist at Blue Pearl in Tacoma, who recommended amputation of Rainier's front leg followed by four rounds of chemotherapy. While at the clinic, Bentz learned about Dr. Mamula's experimental cancer vaccine and immediately enrolled Rainier in the trial.
The vaccine protocol involved two shots administered several weeks apart. For eight months, Rainier showed no signs of cancer. However, in July, scans revealed metastasis to his lungs.
After a failed attempt with another form of chemotherapy that made Rainier severely ill, Bentz reached out directly to Dr. Mamula at Yale as a last resort.
"I didn't think I'd ever hear back," she said. "I figured he's a very busy person, but he contacted me the same day."
Dr. Mamula reviewed Rainier's records and determined he was eligible for a booster of the vaccine. The results were astonishing – recent X-rays showed the mass in Rainier's lungs had completely disappeared.
"There are no signs of cancer right now with Rainier and I'm shocked but super excited," Bentz said. "He runs and plays just like he's a puppy."
Expanding Access to Canine Cancer Immunotherapy
The promising results from these and other cases have generated significant interest in the experimental vaccine. Currently, the treatment is being tested at 13 sites across North America, including two in Washington state: Bridge Animal Referral Center (BARC) in Edmonds and Washington State University's Veterinary Teaching Hospital in Pullman.
The trials continue to accept eligible dogs, offering hope to pet owners facing devastating cancer diagnoses. The Canine Cancer Alliance is supporting these efforts through fundraising events like the annual "Wag Love Life Walk and Run" in Redmond, which helps fund research and enroll pets in clinical trials.
Scientific Significance and Future Directions
The success of these immunotherapy approaches in canine patients has important implications for both veterinary and human medicine. Cancer is the leading cause of death in dogs, and traditional treatments often come with significant side effects and limited efficacy against metastatic disease.
The inhaled IL-15 immunotherapy studied at UC Davis and the Yale vaccine represent novel approaches that harness the body's immune system to fight cancer. The observation of pseudoprogression in Lola's case mirrors phenomena seen in human immunotherapy patients, highlighting the value of these canine studies for comparative oncology research.
As these trials continue to enroll patients and gather data, researchers hope to refine protocols and expand access to these promising treatments, potentially changing the standard of care for canine cancer patients and providing valuable insights for human cancer research.
