The Comparative Oncology Program at the National Institutes of Health is celebrating its 20th anniversary of advancing the study of cancer in dogs to help canine and human patients. AVMA News spoke with the founding and current directors of the program and two other veterinarians in the field of canine comparative oncology about their work and the importance of the program. This is the third article in a three-part series.

By Katie Burns

March 20, 2023

The Comparative Oncology Program at the National Institutes of Health has transformed canine comparative oncology since the program’s founding 20 years ago, according to Dr. Deborah W. Knapp at Purdue University and Dr. Steven Dow at Colorado State University, two of many veterinarians working in the field.

Helping pets and people

Dr. Knapp directs the Werling Comparative Oncology Research Center at Purdue University College of Veterinary Medicine and serves on the steering committee for the NIH-funded Integrated Canine Data Commons. Purdue’s program in canine comparative oncology was formed back in 1979 and has participated in the Comparative Oncology Program at the NIH since the start.

Dr. Knapp began her career working in a small animal practice, where she observed anti-cancer effects in dogs on piroxicam, a nonsteroidal anti-inflammatory drug. She studied the topic during her residency in veterinary oncology at Purdue. She later joined the Purdue veterinary faculty, and her research has focused on bladder cancer in dogs—which responds strongly to piroxicam.

Furthermore, bladder cancer in dogs is similar to muscle-invasive bladder cancer in humans. Now piroxicam is widely used in canine oncology, and there have been studies in human medicine of drugs in that class.

“I love the opportunity to help people with their pets when I know how incredibly important that is, and you form those bonds with the owners, and you’re helping their animals,” Dr. Knapp said. “And then at the same time, you’re generating information that can help human cancer patients. And for me, that’s a very special opportunity to have.”

Dr. Knapp said the Comparative Oncology Program at the NIH catalyzed the whole field—giving legitimacy to it, bringing in funding, and coordinating efforts.

Recently, Dr. Knapp and her team finished a study on early detection of bladder cancer in Scottish Terriers, with the results published by Frontiers in Oncology in November 2022. She said, “By the time we see animals with cancer, which is very similar to when physicians see people with cancer, the cancer can be pretty advanced before the diagnosis is even made.”

Scottish Terriers are at high risk of bladder cancer. The team followed 120 dogs that were at least 6 years old at the start of the study, screening them every six months for three years, and found bladder cancer in 32 of the dogs before any outward evidence of cancer. Treatment with deracoxib, another NSAID, was much more effective after finding the cancer early.

Old and new

Dr. Dow, a professor of clinical sciences at Colorado State University College of Veterinary Medicine & Biomedical Sciences, got involved with the Comparative Oncology Program at the NIH years ago when CSU was one of the sites running immunological assays in support of several studies through the program’s Comparative Oncology Trials Consortium.

Dr. Dow’s focus is developing immunotherapies for dogs with cancer. He participated in the first round of the PRE-medical Cancer Immunotherapy Network Canine Trials. The NIH funded PRECINCT first in 2017 and again at the end of 2022. Dr. Dow’s laboratory repurposes older drugs designed for other diseases, such as medications for hypertension that have immunological properties that make them promising for cancer treatment.

A recent study out of the laboratory found that using losartan, a medication for hypertension, combined with toceranib, a cancer drug, resulted in tumor stabilization or regression in half of dogs with advanced relapsed metastatic osteosarcoma to the lungs. The results of the osteosarcoma research were published in Clinical Cancer Research in February 2022.

The laboratory also studies other drug combinations that could be used in veterinary clinics now. Dr. Dow said: “These drugs, they’ve been around for a long time. They’re generic, the cost is affordable, and they have good safety margins.”

Malignant gliomas are aggressive brain tumors that share similarities between dogs and humans. A second study from Dr. Dow’s laboratory, published in Cancer Research Communications in December 2022, found that the combination of losartan and propranolol, a beta blocker, along with a cancer vaccine induced durable tumor responses in eight of 10 dogs with gliomas.

Dr. Dow said he thinks the biggest impact of the Comparative Oncology Program over the past two decades has been to increase the visibility of dogs with cancer as a translational model for humans with cancer, benefiting researchers whether or not they work directly with the program.

The role of the program has been not only creating networks, he said, “but also stimulating these interest groups that really begin to think deeply about cancer in dogs and how it applies to similar cancers in humans.”