Taking A Shot At Treating Equine Melanomas

Studies show that 80 percent of grey horses over the age of 15 will develop melanoma—some lesions are simply cosmetic issues while others are aggressive tumors that can harm internal organs. Cancer cells are aberrations of normal cells in an animal’s body that are not recognized as foreign, therefore escaping immune system detection and allowing them to divide and spread over normal tissue.Treatment for melanoma has evolved over the years and there are currently two vaccines up for USDA approval.

Morphogenesis Inc. researchers have identified a bacterial gene that can trigger the immune system to recognize and attack tumor cells. Called IFx-VETDirect Immunotherapy, a veterinarian injects the DNA from the gene directly into the melanoma, which results in significant tumor remission, reports The Horse.

The injections need to be administered biweekly then twice more monthly. Once the DNA is present, it will kill the tumor as well as cause a systemic response to kill cancer found elsewhere in the body.

In one study, 77 percent of the horses given IFx-VETDirect Immunotherapy had tumors that regressed over 35 weeks. There were no issues with bloodwork during that time. All 22 horses vaccinated for the study showed control of the tumors or at least a 30 percent decrease in lesion size.

The second vaccine that awaits USDA approval in horses is already in use in canines for oral melanomas. Called Oncept, it does not cure oral melanomas in dogs, but does extend the life expectancy of the affected animal.

The DNA in the vaccine stimulates the production of human tyrosinase; tyrosinase controls the production of melanin pigment in many species and is also produced by cancerous melanoma cells. By using a human tyrosinase, the animal’s body recognizes it as a foreign body and works to remove it, along with the cancerous melanoma cells. The immune response to tyrosinase is similar in both dogs and horses.

Vaccination administration is typically four injections every two weeks into the pectoral muscle. A booster is then given every 6 months, most likely for the entirety of the horse’s life. Of the 15 horses used in the study, 80 percent experienced a positive response, with 12 that had at least a 30 percent reduction in tumor size.

Great success has been found when using the Oncept vaccine when melanoma lesions first appear; many horses have resolution of the tumors and the remain tumor-free.

Learn more about the melanoma vaccination options at The Horse.

The post Taking A Shot At Treating Equine Melanomas appeared first on Horse Racing News | Paulick Report.

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