Veterinary Stem Cell Therapies Discussed at Fully Vetted Blog

A prominent veterinary blogger, Dr. Patty Khuly of Fully Vetted, has written about the issue of veterinary stem cell therapies. The inspiration for her post appears to have been the recent article in JAVMA News, the news service of the Journal of the American Veterinary Medical Association, which discussed stem cell therapies in veterinary medicine. Dr. Khuly’s post was a pretty fair summary of some issues associated with stem cell therapies, which I have discussed numerous times in the past (for example). She seemed to imply pretty clearly in her conclusion that, though the evidence is not there to prove safety or efficacy, owners who are desperate and whose pets don’t have any other treatment options should have this therapy available to them. I don’t entirely disagree, but I think there may be some unjustified assumptions and a bit of a false dichotomy in her  conclusion:

Given the reality that the pets most affected by this are those with conditions that are untreatable by any conventional means, and that time-consuming clinical trials would require onerous delays in treatment, is it wrong to keep this therapy out of owners’ hands? Or is it worse to fail to live up to the oath that exhorts us to act as scientists first?

This question is a bit like “Have you stopped beating your wife?” in that there it contains assumption that may not be true and makes any answer imply something other than what is really meant. I certainly don’t disagree that for pets with severe arthritis and no other treatment options that stem cell therapy is worth trying, but I doubt that constitutes the bulk of the market for these treatments. And I think the objections I and others have raised to the aggressive marketing of stem cell treatments have a bit more to them than an intellectual desire to “act as scientists first.”

Here is the reply I posted to Dr. Khuly’s blog. Anyone interested should take a look at her post and consider participating in the discussion. Dr. Khuly likely reaches a much larger audience than I do, so it would be useful to have a variety of perspectives in the discussion there.

Dr. Khuly,

I’m happy to offer my take on the stem cell question, especially since this seems to be a subject on which I am all too easily misinterpreted. I certainly wouldn’t call myself a “naysayer,” for example. As I’ve said repeatedly, I see great promise in stem cell therapies, and I am cautiously optimistic that they will eventually be a useful tool.

My concerns have more to do with the widespread and aggressive marketing of a therapy in advance of adequate evidence to demonstrate safety and effectiveness. We are all familiar with drugs that had great promise, and that passed far more extensive pre-market testing than stem cells have undergone, and which later turned out to have less benefit than hoped or unexpected hazards (e.g. Vioxx, thalidomide). There have also been many procedural treatments like stem cell therapy which have come on the scene, enjoyed great popularity, and then turned out to be less useful or more dangerous than hoped (e.g. internal mammary artery ligation). The lesson is that the way things seem isn’t always the way things are, and good quality research isn’t just a nice extra, it is critical to making the best choices for our patients.

Given the reality that the pets most affected by this are those with conditions that are untreatable by any conventional means, and that time-consuming clinical trials would require nerous delays in treatment, is it wrong to keep this therapy out of owners’ hands?

I think you may be unintentionally setting up a bit of a false dichotomy here. You seem to be assuming that all the pet owners clamoring for this new treatment are those whose pets have serious arthritis symptoms that do not respond to currently available treatments. (The vast majority of stem cell treatments in small animals, which is my field, are marketed and used for arthritis, so that is what I will address here. As you point out, other applications are primarily still only available in the context of academic research). I am not aware of any objective statistics, but I suspect this isn’t true and that the market for stem cell therapies would be very small if it were limited to such cases. I frequently field inquiries about this therapy from people who have not taken full advantage of existing available treatments for arthritis, the most popular application for autologous stem cell treatments.

There are many therapies for arthritis which are well-established to be effective. Weight loss, physical therapy, non-steroidal anti-inflammatory medications (NSAIDs) are the most common examples. The majority of patients with arthritis respond well to these therapies. However, there is no free lunch in medicine, so anything with a benefit is going to have a downside.

Meaningful weight loss requires restricting a pet’s calorie intake significantly. The pet is going to be noticeably hungry and likely to beg or scrounge for food, and this is understandably hard for many owners. I spend a lot of time counseling owners on nutrition trying to prevent and treat obesity, but the reality is that many owners are not able to stick to a serious weight loss regime for their pets, particularly for older and relatively inactive pets.

Physical therapy is a great intervention, but it has its costs as well. Some are financial, and there is a significant investment in time and energy as well as money for owners seeking this kind of care. We are fortunate to have dedicated physical therapy facilities nearby, but not all veterinarians can easily offer or refer for this treatment, and not all owners readily take advantage of it.

And then, of course, there are NSAIDs. I would never consider denying that they have potentially serious side effects, but the evidence is very clear that, when properly used and monitored, they are very effective and very safe for the overwhelming majority of patients with severe arthritis (e.g. http://skeptvet.com/Blog/2010/12/safety-and-efficacy-of-nsaids-for-canine-arthritis/). Unfortunately, appropriate concern about potential side effects easily becomes irrational fear, and some pet owners avoid NSAIDs unnecessarily.

There is definitely a balance to be achieved between the need to act and the uncertainty about whether our actions will help or harm. For those patients who cannot maintain an acceptable quality of life using existing treatments with well-established benefits and risks, I have no objection at all to offering stem cell treatment as an experimental approach. Ideally, this would include some kind of objective, structured assessment of outcomes, both beneficial and unintended. Casual assessment by owners and individual veterinarians, or uncontrolled research by companies selling the therapy, will always show a benefit and miss all but the most dramatic side-effects for any therapy, so this can’t be our only form of assessment.

I think it is instructive to look at how differently stem cell therapies are being handled in human medicine. The major organization representing stem cell researchers, the International Society for Stem Cell Research, has said:

We have all heard about the extraordinary promise that stem cell research holds for the treatment of a wide range of diseases and conditions. However, there is a lot of work still needed to take this research and turn it into safe and effective treatments.

The International Society for Stem Cell Research (ISSCR) is very concerned that stem cell therapies are being sold around the world before they have been proven safe and effective.

Stem cell therapies are nearly all new and experimental. In these early stages, they may not work, and there may be downsides. Make sure you understand what to look out for before considering a stem cell therapy.

Remember, most medical discoveries are based on years of research performed at universities and companies. There is a long process that shows first in laboratory studies and then in clinical research that something is safe and will work. Like a new drug, stem cell therapies must be assessed and meet certain standards before receiving approval from national regulatory bodies to be used to treat people.

(http://skeptvet.com/Blog/2010/06/stem-cell-therapy-still-an-uncontrolled-experiment-on-our-pets/).

These people have devoted their careers to studying stem cell therapies, so they can’t simply dismissed as “naysayers” as so often happens when skeptics such as myself raise concerns. Stem cell therapies are moving forward much faster in veterinary medicine than in human medicine not because we have better data or a more serious problem to be addressed, but because we have more lax regulation and fewer concerns about lawsuits if something goes wrong. Hopefully, in the end this will turn out to be a good thing because these therapies will be proven safe and effective. However, we cannot totally ignore the possibility that proceeding without rigorous pre-market testing and post-market surveillance will lead us to doing harm unintentionally, or wasting time and resources on an ultimately ineffective therapy.

Just to be completely clear:

1. Stem cell therapy is indeed a promising, though as yet unproven, new therapy. However, only clinical trials can truly show it to be safe and effective, or not, so our current headlong rush into this field based on preclinical findings and individual patient anecdotes is not without risks.

2. Given the uncertainties about the safety and efficacy of this expensive and invasive procedure, all other treatments with established risks and benefits should be utilized fully before we turn to stem cell therapy. This includes NSAIDs which, though not without risks, are very effective and generally much safer than most of my clients seem to think.

3. For those patients who cannot achieve a good quality of life with established treatments, it is perfectly appropriate to offer stem cell therapy as an option. In human medicine, such treatments are generally available through clinical trials or special “compassionate use” provisions. This may not always be practical in veterinary medicine, but we should make our best effort to objectively and systematically assess the outcomes of patients treated with stem cells.

Think about how long it took for us to make the connection between certain vaccines and cancers that developed rarely and many years later. If a similar unanticipated risk exists with stem cell treatment, we’re going to miss it if we are looking carefully, and that would be irresponsible. I would like to see less aggressive, more fact-based marketing and more effort given to evaluating objectively the benefits and unintended effects or complications of these procedures.

You ask if we have the right to keep a potentially beneficial therapy with uncertain risks and benefits from owners who want it. I would phrase the question differently. Do we have a right to sell owners a potentially beneficial therapy with uncertain risks and benefits, often through misleading and unjustifiably positive marketing? Don’t we have a responsibility to ensure as best we realistically can the safety and effectiveness of any therapy we offer our patients?

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