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Melanoma Vaccine Success

SC-MelanomaVacAn excellent example of comparative oncology is the clinical trials that commenced in 2000 for a therapeutic DNA-based vaccine aimed at treating canine melanoma (the trials in which Puccini participated). The vaccine was developed through a partnership between veterinarians at New York’s Animal Medical Center (AMC), researchers at Memorial Sloan-Kettering Cancer Center (MSKCC), and Merial (a leading producer of pharmaceutical products for animals). While MSKCC was testing a human melanoma vaccine, they received an inquiry from Dr. Philip Bergman (who at the time was with The Animal Medical Center) seeking novel treatments for canine melanoma. The discussions resulted in collaborative clinical trials of the MSKCC vaccine.

The lead investigators were Dr. Bergman, then head of the Donaldson-Atwood Cancer Clinic and Comparative Oncology Laboratory at The AMC, and Dr. Jedd Wolchok, medical oncologist and specialist in metastatic melanoma at MSKCC. Dr. Bergman is now the director of Clinical Studies for VCA Antech, Inc.

Dr. Bergman calls the vaccine a “critical advance in veterinary medicine that also offers hope for human patients with melanoma.” It works like this: the vaccine is xenogeneic, meaning it takes biological material from one species – in this case human DNA (targeting tyrosinase, an enzyme which is found in melanoma cells) – and injects it into another species to trigger the immune system to attack the cancer. Vaccine tests administered to humans at MSKCC contained mouse and human tyrosinase DNA.

The vaccine, Dr. Bergman explains, “tricks the body into recognizing cancer as a foreign entity, then the immune system acts to eliminate it. The same strategy we have used in dogs is now being investigated in people.” The cancers are similar, he says, and metastasize in roughly the same places – local lymph nodes, lungs, lining of the brain, and adrenal glands – which have proven chemotherapy resistant.

The clinical trials conducted between 2000 and 2007 in dogs with malignant melanoma, including Puccini, involved administering the vaccine four times over eight weeks with radiation treatment, followed by boosters at six-month intervals for the remainder of the animal’s life.

As a result of the clinical trial success, the vaccine (marketed as ONCEPT™) received conditional USDA approval in 2007 and became the first therapeutic cancer treatment approved by the USDA for either animals or humans. ONCEPT was granted full USDA-approval in 2009.

Dogs get cancer for the same reasons humans do, explains Dr. Jedd Wolchok of Memorial Sloan Kettering Cancer Center, and both live in the same environment. Thus, by conducting tests on both species, he says, “there can be a synergy that we hope will result in improved cancer treatment for all.”

Dr. Bergman claims the fast-developing friendship between he and Dr. Wolchok, their mutual frustration treating human and canine melanoma patients, the vaccine’s quick advancement through bureaucracy, and logistics (the two facilities are only four blocks apart) combined to play a key role in the vaccine’s release to veterinary oncologists nationwide in June, 2007.

“It’s all about teamwork and rapport,” Dr. Bergman emphasizes. “In scientific research, sometimes it’s the smallest things behind the scenes that keep projects moving forward. Human dynamics are a critical part of the big picture, but usually aren’t recognized.”

Bob Nordgren, Merial vice president of biologics research, technology and product acquisition was tightly involved with Drs. Bergman and Wolchok throughout the developmental process. Merial estimates more than 7,500 dogs have been given the vaccine to date.

All information from the canine clinical trials was shared with Memorial Sloan-Kettering Cancer Center and is being used in ongoing research to investigate the potential implications for the vaccine in humans.

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