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THE first monoclonal antibody approved for veterinary use in the European Union, Cytopoint, was launched this week.
A single injection of Cytopoint treats the clinical signs of atopic dermatitis in dogs, including itch and inflammation, for up to one month.
The monoclonal antibody (MAb) treatment works by mimicking the activity of natural antibodies to selectively bind to and neutralise interleukin 31 (IL-31), a key protein involved in cell communication which triggers itching associated with atopic dermatitis in dogs. Because it neutralises IL-31, it has been demonstrated not to interfere with the immune response, meaning that it does not induce unintended immunosuppression or enhancement.
Manufacturer Zoetis says treatment provides long-lasting relief from itching and inflammation within eight hours, allowing damaged skin to heal, in this way it improves the long-term quality of life for atopic dogs and their owners.
In clinical studies submitted to the European Medicines Agency, the efficacy of cytopoint was evaluated and showed that treatment reduced itching and the severity of skin disease. As well as improved efficacy, no adverse effects were reported and it was not found to interact with other drugs.
How do monoclonal antibodies work?
All mammals produce antibodies to protect against foreign proteins or antigens introduced in to the body.
The production of therapeutic MAbs begins with mice being immunised with a specific target antigen. The antibodies harvested in this process are highly specific to the antigen of interest. Recombinant DNA techniques are then used to fuse the antigen binding sites of the murine MAbs with DNA from the target species, in this case dogs, to create caninised MAbs with the selected antigen binding sites.
When the new MAbs are injected into the animal the antigen-binding fragment on the antibody interacts with specific targets on proteins (like cytokines) in the blood and tissue, this prevents these molecules from binding to their receptors and subsequently activating an immune response. Alternatively, a MAb can bind to a target receptor on a cell surface to block its activation (antagonistic MAbs).
The nature of monoclonal antibodies means that they have three main safety advantages over traditional pharmaceuticals: they have very specific targets; they don't have any intracellular activity so there are fewer anticipated side effects; they are not metabolised by the kidney or liver but are catabolised within the cells resulting in amino acids which are recycled within the body.
Speaking at the launch in the UK this week, Andy Hillier, Veterinary Specialty Operations and Medical Lead Allergy, Dermatology at Zoetis said ‘Monoclonal antibody therapy is the fastest growing therapeutic area in human medicine, and Zoetis has focused on how these therapies can be translated to animal health. MAbs mimic the activity of the naturally produced antibodies without provoking an immune response from the host.’
Canine atopic dermatitis is a genetically predisposed inflammatory and itchy allergic skin disease associated with exposure to environmental allergens, such as pollen, mites and mould spores. One in every six dogs is treated by a vet for itch and 15 to 20 per cent of those dogs are diagnosed with atopic dermatitis.
Traditionally, glucocorticoids, cyclosporine and immunotherapy have been the main treatments for atopic dermatitis. Though effective in some instances, these treatments have limitations, including their potential for adverse events.
Cytopoint was launched in the US over a year ago and cases, including those that have not responded to previous treatment, have shown rapid improvement of signs even after just one injection.
Cytopoint is licensed for dogs of any age, even those with concomitant diseases and can be used with many common medications, including vaccines. It also functions as a normally occurring antibody and is eliminated via normal protein degradation pathways in the same way, with minimal involvement of the liver or kidneys. These benefits make MAbs a good candidate for treating a broad range of dogs.
What is the potential for other veterinary treatments?
Monoclonal antibodies have been used to treat many conditions in people over the last 20 years, including cancer, arthritis and asthma.
Cytopoint is the first monoclonal antibody to be licensed for veterinary use in the EU. Pharmaceutical company Aratana also has full US approval for a MAb treatment for B-cell and T-cell lymphoma in veterinary use.
It is expected that, as in human medicine, improved understanding of the pathophysiology of veterinary diseases could also lead to the identification of new targets for the development of MAbs for many other conditions, including osteoarthritis pain, chronic kidney disease, oncologic conditions and cardiac disease.
Sarah Warren, a referral dermatologist for CVS, who will be one of the first vets to use this new treatment in practice as part of the early experience programme, said she would regard cytopoint as a major anchor therapy for treating atopic dermatitis in dogs ‘there's no question that dealing with flares in atopic dermatitis is one of the biggest challenges, whether they're caused by seasonal peaks in allergen load or time of year, managing those flare factors can be the biggest challenge in veterinary practice and this therapy has a key role to play in that.’
She said atopic dermatitis was an incredibly common, debilitating condition and it would be good to have a treatment available for seasonal flare ups over the lifetime of patients. She said having a non-drug option to treat dogs was particularly appealing ‘without question there are a definite body of pet owners for whom drugs are seen as a negative, whether that's perception or experience or a bit of both, there will be a lot of positivity at being able to offer a non-drug therapy.’
The price is yet to be determined but it is expected by be less than £2000 per treatment.
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