Paul Knoepfler, PhD, is an associate professor at UC Davis School of Medicine with a special research interest in stem cells and cancer. In addition to his research, Dr. Knoepfler is the creator of the Knoepfler Lab Stem Cell Blog, through which he tries to inform people about legitimate stem cell research, and warn them about the rise of stem cell clinics offering unproven and sometimes risky stem cell treatments. Knoepfler is also the author of the book Stem Cells: An Insider's Guide, that examines the ethical issues and regulations surrounding stem cell transplants.
You are a stem cell researcher, yet you publicly warn patients to beware of this therapy. Why?
Frankly, there's a lot of stem cell snake oil out there. We’ve seen a rise in stem cell tourism—clinics worldwide selling treatments that are not proven safe and effective. I don't think the average patient can easily navigate the wild universe of stem cells and be confident they know whether a particular treatment would be safe and effective. Many clinics forgo the usual, accepted path of FDA pre-approval of an experimental therapy such as stem cells.
Are there conditions for which it makes sense to get a stem cell transplant today?
Not many. Bone marrow transplantation and hematopoietic stem cell transplants are the most established. Otherwise things are experimental and risky.
Which conditions are being treated with stem cells without evidence that they work?
Many predatory stem cell clinics offer a whole menu of dozens of conditions for which they sell "treatments." For example, a single clinic may sell an adipose (fat) stem cell therapy for 15 conditions, none of which have anything to do with fat. The conditions may range from musculoskeletal disorders to neurological diseases to pulmonary conditions—and the doctor providing the stem cell treatment may have no expertise in those conditions.
What are the key problems with stem cell therapies offered at these clinics?
There are many issues of concern. Some I mentioned earlier, including the lack of FDA approval, the lack of physician expertise in the area of the patient's disease, the lack of logical reason why a fat stem cell therapy would help a given condition, the lack of proper informed consent, and the lack of compelling data backing up the treatment.
Stem cells are also often administered in ways that don't make a whole lot of sense, such as intravenously (IV) for a brain condition. Stem cells can cause abnormal tissue growth that—even if benign—can be destructive to surrounding tissues. Stem cells can also cause cancer, pulmonary emboli, and immune reactions.
Does the FDA regulate these procedures in any way?
The FDA regulates biological drugs and products, including stem cell therapies. But the FDA does not regulate the doctors directly, as that is the responsibility of state medical boards. And the doctors at stem cell clinics are using the drugs and devices "off label" in ways that were not FDA approved. Is this illegal? We don't have a clear answer, particularly because the FDA has not taken any clear action in the last couple of years on this. (Previously the FDA had issued warnings to stem cell clinics.) The lack of FDA action has created a gray zone in which hundreds of clinics are now operating. That gray zone could suddenly collapse or instead things could stay murky for quite some time. Stuck in the middle are patients.
What precautions should patients take when offered stem cell therapy by a doctor?
I recommend that patients talk to their primary care doctor about whether a stem cell therapy might be advisable or not. Patients should weigh the potential risks versus possible benefits, ideally using actual data. They should consider other options, and do as much homework as they can. Unfortunately many patients are understandably desperate for hope; predatory clinics take advantage of such patients. For many patients, cost is also an issue. A single stem cell treatment can cost $10,000, and many patients get more than one transplant. I strongly recommend against letting celebrity patients such as sports stars be the inspiration for stem cell therapy.
As a scientist, why did you decide to start blogging about stem cell research?
I noticed in late 2009 that there was a gap in the stem cell world. Social media and the Internet were dominated by the stem-cell clinic industry promoting this therapy, and by activists opposed to using stems cells from embryos for any medical reason at all. There was a need for a rational voice advocating for the stem cell field and evidenced-based medicine. I would also emphasize that there is much to be excited about with regard to stem cells and hundreds of legitimate clinical trials out there. I am hugely optimistic that stem cells will become a major part of mainstream medicine. But it is important not to jump the gun and do more harm than good by going too fast.
This opinion does not necessarily reflect the views of the UC Berkeley School of Public Health or of the Editorial Board at BerkeleyWellness.com.