Fred, a 6-year-old male shepherd cross, was diagnosed by his referring veterinarian with cancer in his left forelimb in April 2016. Due to preexisting orthopedic issues, he was not a candidate for the traditional amputation and chemotherapy treatment. Faced with only being offered palliative care for Fred, his dedicated owners, Rob and Linda, continued to hope and sought out other options. They discovered a new clinical trial at the UC Davis veterinary hospital that offered a cutting-edge approach to treating dogs with osteosarcoma.
“From the first meeting, we knew Dr. Michael Kent, Teri Guerrero (oncology clinical trials coordinator), and the entire UC Davis team would take great care of Fred,” Rob said.
The trial, sponsored by the National Cancer Institute (NCI) and being run in conjunction with the UC Davis School of Medicine’s NCI-designated Comprehensive Cancer Center due to a special interest in its future applications to human medicine, investigates the potential of a dog’s immune system to be manipulated to fight off its own cancer. After irradiating the tumor, veterinarians collect a particular type of the dog’s white blood cells, known as Natural Killer (NK) cells, then stimulate and grow the cells in a laboratory before injecting them back into the dog’s tumor. Ideally, the lung metastasis, or the spread of the tumor to the dog’s lungs (which occurs in more than 90 percent of osteosarcoma cases), will be slowed or stopped entirely by these NK cells.
Fred’s treatment started with palliative radiation to help control the local disease and reduce pain as well as to create a signal to the immune system that the NK cells could react to. He also began receiving monthly injections of zoledronate, a drug used to help prevent fractures in bones stricken with cancer. The following three weeks of radiotherapy ran seamlessly, and Fred’s sweet demeanor and fuzzy, lovable appearance quickly made him popular amongst the team of veterinarians, technicians, and students in the Oncology Service who cared for him.
Following radiation therapy, Fred received the first of two intratumoral NK cell injections without any complications. During the appointment for his second NK cell injection, Dr. Kent, the lead investigator on the trial, noticed Fred’s hesitation to bear weight on his left front leg. He consulted with the Orthopedic Surgery Service, and with the help of the Diagnostic Imaging Service, the team of veterinarians discovered fractures to both the radius (where the tumor was located) and the ulna, which is typical given the nature of Fred’s disease. A temporary splint was put in place and the second NK cell injection was given as planned. Several days later, orthopedist Dr. Po-Yen Chou surgically repaired Fred’s fractures.
By August, a CT scan revealed exciting news for both Fred and the osteosarcoma trial – there was no evidence of tumor spread or metastasis. Fred continued to receive zoledronate injections for two more months, and concluded his participation in the clinical trial at the end of October. His owners are thankful for the extension to Fred’s life that this trial has provided.
“No matter the long-term outcome, we feel he has received the very best of care, and that’s why we will always be grateful that UC Davis is able to offer clinical trials,” Linda said. “Making decisions in the treatment for pets that have cancer is never easy, but we have absolutely no regrets, and, as pet parents, that’s as good as it gets.”
This trial will have wide-reaching applications in both veterinary and human medicine. Over the last few years, immunotherapy has become the fourth arm in treating cancer, along with more traditional treatments such as surgery, radiation therapy and chemotherapy. By learning how to overcome immune tolerance and immunosuppression caused by the tumor, this study and other research UC Davis is conducting on immunotherapy hopes to provide oncologists more options for treating cancer in both pets and their owners.
About the Veterinary Medical Teaching Hospital
The William R. Pritchard Veterinary Medical Teaching Hospital at the University of California, Davis—a unit of the #1 world ranked School of Veterinary Medicine—provides state-of-the-art clinical care while serving as the primary clinical teaching experience for DVM students and post graduate veterinarian residents. The VMTH treats more than 50,000 animals a year, ranging from cats and dogs to horses, cows and exotic species. To learn more about the VMTH, please go to www.vetmed.ucdavis.edu/vmth. Timely news updates can be received on its Facebook (www.facebook.com/ucdavisvetmed) and Twitter (www.twitter.com/ucdavisvetmed) pages.
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