Tennis star Rafael Nadal, who crashed out of the Australian Open this week, was reported in late 2013 and again late last year as having received stem cells for his joint and back problems.
This sort of free publicity involving celebrities can only boost business for stem cell clinics, which are already operating in China, Ukraine, Italy, Panama and Mexico, among others. But stem cell science is unsettled and stem cells are not ready for therapeutic use. If so, it is very reasonable to call them rogue clinics that one should keep well away from.
No Singapore-registered doctor may use stem cells except in a formally approved clinical trial. Those who do otherwise, whether they do it here or elsewhere, risk disciplinary action.
Surprisingly, rogue stem cell clinics are flourishing in the United States, and there are now even chains of such clinics on both coasts of the country. If seriously ill Singaporeans reason that medical practice must be regulated stringently in the US, they may well seek stem cell treatment there. Given how much more needs to be done before we can be sure stem cells work safely and for which ailments, these clinics are clearly not as well regulated as one might imagine.
Priced up to US$20,000 a pop just seven years ago, market competition seems to have driven prices down. On its website, one US clinic posts a flat fee of US$7,600 (S$10,300) for treatment of various conditions with stromal vascular fraction (SVF), the stem cell product commonly used in these clinics.
Made from a patient's body fat extracted by liposuction, SVF has not been proven safe or effective. In fact, neither that nor any other stem cell product offered by these clinics has been licensed by the Food and Drug Administration (FDA), the country's drug and medical devices regulator.
Only one type of stem cell has been available for hospital use in Singapore for over two decades - blood stem cells used to treat blood cancers, mainly. This apart, any other stem cell treatment ought to be regarded as little more than quackery.
So, how do the clinics justify their promotion of stem cell treatments?
First, they say their stem cell products are not drugs. Technically, they claim that these products are "less than minimally manipulated", which refers to an FDA requirement that if a biological product is "more than minimally manipulated", it is, by definition, a drug that must secure a licence from the regulator for use. These clinics say their stem cells are not even minimally manipulated. Indeed, they are just extracted from a patient's tissues, so how can they be drugs at all? Since they are not drugs, they need no FDA licence, the clinics argue.
Second, the clinics claim that the risks are minimal because the patient is both source and recipient of the stem cells used in a process that is even completed in a same-day surgical procedure.
Take SVF, made from the patient's fat which is first treated with enzymes to break it down before being centrifuged to isolate the cells found within. The end product is SVF, which is administered to the same patient as her very own fat-derived stem cells.
The risks are minimal, these practitioners reason.
A December 2013 study published in Plastic And Reconstructive Surgery, comparing four commercially available SVF machines, found their outputs to vary greatly in the types, quantity and identity of stem cells. This means that what one clinic calls SVF could be quite different from what another clinic calls SVF. Whether such differences matter is not known since they have not been subjected to clinical trials.
But even if it could be produced with a consistent quality, SVF is not risk-free just because it is made from a patient's own fat. In fact, its use carries at least two risks. The first is that of pulmonary embolism. This is when some ingredient in SVF enters the blood stream and becomes lodged in an artery in the lungs, blocking it. This is frequently fatal.
The second is the growth of inappropriate tissues because the stem cells found in SVF, if any, can develop into not just fat tissue but hypothetically also blood vessels, bone and cartilage. Imagine if some bone grew in the eyes from the use of SVF.
By contrast, the use of blood stem cells in treating blood cancers is safe because their use is consistent with the source tissue's properties. Sourced from blood, these blood stem cells are used to treat only blood cancers.
SVF, however, is used to "treat" everything from heart attacks to strokes and brain trauma. It has also been injected into knees, hips and shoulders ostensibly to repair cartilage and ligaments, as well as to try restoring hair and a youthful face. But these conditions have little to do with fat tissues from which SVF was extracted. In China, there have been anecdotes of teeth being found in the brains of stem cell patients.
Nevertheless, some stem cell clinics try to allay such fears by claiming that what they do is actually an "approved" clinical trial. Indeed, they may even be able to show you that they have stem cell trials listed on ClinicalTrials.gov, a public database of both non- profit and for-profit trials going on inside and outside the US. For example, a US chain of stem cell clinics has a trial listed on this database with the stated aim of enrolling 3,000 subjects.
But what most patients and even many doctors may not know is that ClinicalTrials.gov is an "honour system". In such a system, you are bound only by your honour to act ethically: No one scrutinises or monitors you.
So trials listed on this database are not vetted or monitored for compliance with FDA requirements, ethics committee guidelines or other key indicators of an ethical trial. Thus, patients are not protected just because their stem cell clinic has a trial listed on the ClinicalTrials.gov site.
Nevertheless, such a listing does give the clinic a patina of legitimacy, which it may exploit for marketing purposes. Why, then, has neither the FDA nor any of the physician licensing boards that cover each state of the US come down on such clinics?
To cut a long story short, this is a function of politics in "the land of the free and home of the brave". Perhaps, only a bunch of disastrous cases will force the authorities into action. Meanwhile, one should avoid stem cell clinics anywhere they may be found.