Those working in veterinary medicine are on the brink of having a new treatment option for combatting one of the most painful and debilitating of diseases in cats – feline chronic gingivostomatitis (FCGS). This disease affects approximately 10% of the feline population (upwards to 25% of cats in some parts of the world) and approximately one third of those cats don’t respond to conventional treatment approaches.
Sonruvetcel looks to be the first FDA approved off-the-shelf mesenchymal stromal/stem cell (MSC) therapy in veterinary medicine (pending conditional FDA-approval which is anticipated late Spring 2026). Additional research is underway to evaluate MSCs for a variety of other diseases including osteoarthritis in dogs and cats, atopic dermatitis in dogs, chronic kidney disease and asthma in cats, chronic inflammatory enteropathy (IBD), as well as inflammatory diseases of the brain (encephalitis).
Rebecca Windsor, DVM, DACVIM (Neurology) – Director of Veterinary Affairs at Gallant – recently spoke with us about stem cell therapy and helped to clarify how it works, the evidence pointing to its effectiveness, as well as misconceptions about this form of treatment. This is an excerpt from some Q&A with Dr. Windsor regarding her discussion of stem cell therapy:
Question: You talked about a number of different conditions and mentioned doses of stem cells that have been used during clinical trials. Do you anticipate, or should we expect, that the dosing and/or dosing intervals are going to be the same for treating all of these different diseases?
Dr. Windsor: That is such a great question. The literature we have shows a wide variability in stem cell dose, frequency, and routes of administration. This makes it difficult to compare the results and make conclusions because a dose of stem cells given by one route – intravenously, as an example, versus subcutaneously - isn’t necessarily going to have the same end effect. We also need to learn more about how many doses are necessary and at what interval.
In our clinical trials at Gallant, we are dosing patients in a very controlled manner. We have evaluated a consistent dose, for example 20 million stem cells IV given in 2 doses 2-4 weeks apart, as a starting point to demonstrate safety and efficacy. Over time we may see that lower doses could produce a similar clinical response. We will learn more as more studies are designed to specifically evaluate different doses and frequencies.
Question: You talked about stem cells being used to treat feline asthma and encephalitis in dogs. There was such a difference in the time it took to see an effect from stem cell therapy between those diseases. You indicated it could take five to nine months to see an effect in cats with asthma, yet the Pugs with necrotizing meningoencephalitis showed initial improvement within 24 hours of administration. Is there a reason why there is such a difference?
Dr. Windsor: Another great question and, honestly, I do not really know the answer. However, I do think it has a lot to do with how the cells work within individuals for a particular condition. As we discussed, stem cells have a lot of effects. Their anti-inflammatory effects can be seen pretty quickly. I mentioned that for most inflammatory conditions, these patients are living in a systemic pro-inflammatory state. In these conditions with a high degree of systemic inflammation, IV stem cells may demonstrate a rapid effect - as the anti-inflammatory effects are thought to be almost immediate after IV administration. Encephalitis is likely one of these conditions. Contrary to what most people believe, inflammation in encephalitis patients starts outside of the brain, and reducing this systemic inflammatory response may result in more rapid improvement. Asthma is a chronic condition in cats characterized by chronic airway pathology. For diseases with chronic, severe pathology, I suspect stem cells are less likely to have an immediate effect. We suspect the stem cells do reach the diseased tissue, but it’s going to take them longer to actually repair damaged tissue.
Cats with refractory FCGS treated more than 6 months after extraction, indicating a more chronic disease burden, did not respond as well to MSC therapy as those treated within 6 months. Chronicity may contribute to the degree of tissue damage and that leads to individual variability in response for certain diseases.
There are several factors that affect response to treatment and, at this stage, we don’t have all the answers as to why some patients show dramatic improvement after stem cell therapy and others don’t.
Question: You talked about a lot of common diseases. Is Gallant currently conducting clinical trials to evaluate stem cell therapy in all of them? How can I refer a patient?
Dr. Windsor: We have several ongoing clinical trials at various stages of enrollment. We recently completed enrollment for this stage of canine osteoarthritis, canine atopic dermatitis and feline chronic kidney disease and are currently evaluating that data as patients come off trial. We are still enrolling for this stage of feline osteoarthritis. The whole process is very dynamic, so I would invite veterinarians to check the website at www.gallant.com or email us to inquire about trial enrollment.
Question: Do we know if pet health insurance is going to cover this type of treatment?
Dr. Windsor: Another great question and, from our research thus far, we suspect it will be covered. There are many different insurance companies and they can vary widely in what they cover. However, Gallant’s stem cell therapies will all be FDA-approved drugs and there is no reason that they shouldn’t be covered like any other drug. This is not a fringe or “alternative” therapy. Stem cells have a broader and different mechanism of action than any other drug we currently have available, but our therapies are not “experimental.” They have the assurance of safety, efficacy, and manufacturing consistency that is mandated by the FDA.
As I mentioned in the talk, it’s been an incredibly rigorous process to complete these clinical trials and move through the FDA approval process. All of us at Gallant are so excited to bring the first conditionally FDA-approved stem cell product to veterinary medicine. We also want people to feel comfortable using it. Off-the-shelf stem cell therapy will be new or foreign to many. We’re committed to helping people learn as much as they can about regenerative medicine – specifically stem cells – and that is going to come from programs like what we’re doing together. Pet owners are going to ask their veterinarians questions about this form of therapy, and we want our colleagues to feel comfortable answering their questions. I welcome any individual questions from veterinarians about stem cell therapy. They can email me here.
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