Oakham Veterinary Hospital is now able to offer treatment of equine melanoma with Oncept® vaccine.
Melanomas are tumours most commonly seen in mature grey horses on the skin, primarily of the head, prepuce and perineal region, but growths can also develop in internal organs. The majority of melanomas grow slowly causing few problems however in cases where they do become large they can interfere with vital body functions. Surgery to remove melanomas can sometimes be an option but to the proximity to many vital structures.
The Oncept® vaccine was developed to treat melanoma in dogs and offers an effective treatment for melanoma in horses. It is a DNA-based vaccine that stimulates the body to produce an immune response to a protein found in melanoma cells (tyrosinase). It will target all melanoma cells, both internal and external and those not accessible with other treatments. The drug is licensed in the USA for use in dogs, so treatment of horses in the UK is carried out under the veterinary cascade and is only available under the supervision of specially qualified veterinarians. Preliminary results from use of the vaccine suggest that response to the vaccine is positive in some cases but unpredictable; some horses showed cessation of melanoma growth or even tumour shrinkage, however not all horses responded to treatment. Treatment with the vaccine involves an initial assessment followed by administration of the vaccination at two week intervals for four treatments and then six-monthly boosters.