April 18, 2003
DVM Newsmagazine

Vaccine promising for dogs with skin cancer

New York-Treatment with a new DNA-based vaccine more than tripled the median survival of dogs with canine malignant melanoma from 90 days to an average of 389 days, a new study shows.

Because the cancer is virtually resistant to chemotherapy and radiation in late stages, new approaches, such as DNA-based vaccines, which harness the immune system, are being tested.

The study, which involved nine dogs, is collaboration between veterinarians at The Animal Medical Center (AMC) in New York and researchers at Memorial Sloan-Kettering Cancer Center (MSKCC). Results are reported in the April issue of Clinical Cancer Research.

"Most medicines that we use to treat animals are the same as those given to humans," says Philip J. Bergman DVM, MS, Ph.D., head of the Donaldson-Atwood Cancer Clinic and the Flaherty Comparative Oncology Laboratory at AMC. Bergman was the study's first author.

"This vaccine was first tested in the laboratory at MSKCC and then given to dogs with melanoma after receiving approval from the United States Department of Agriculture and AMC's own Institutional Review Board," he says. "We felt it was useful to see if immunotherapy might help these very sick dogs with advanced melanoma since the response rates for standard chemotherapy were extremely poor with no evidence of improved survival."

Canine malignant melanoma (CMM) is the most common oral cancer in dogs, accounting for one out of 20 cancer diagnoses. CMM is most successfully treated in its early stage by surgery. In advanced stages, the median survival is two to three months.

Four dogs survived for more than 400 days with the longest survivor still alive after more than 615 days. The median survival was 389 days.

Other study contributors from AMC are: Josephine McKnight, DVM, Andrew Novosad, DVM, Sarah Charney, DVM, John Farelly, DVM, Ann E. Hohenhaus, DVM, and Diane Craft, BS.

The study was supported in part by the National Institutes of Health, Bioject, Inc. and Merial Ltd.