"In almost every state now, people can go locally to get stem-cell 'treatments,' " said Paul Knoepfler, a stem-cell scientist at the University of California at Davis School of Medicine and one of the authors of the study, published Thursday in the journal Cell Stem Cell. "That's different from what we typically think about when we think of stem-cell tourism."
Knoepfler and his co-author, Leigh Turner, associate professor at the Center for Bioethics at the University of Minnesota, didn't accuse the clinics of operating illegally but called on federal officials to step up their oversight. "What worries us is the possibility of serious harm to patients," Turner said.
Stem cells are a source of keen interest because they can be coaxed into becoming almost any type of cell and thus might offer remedies for many medical problems. But they also carry risk: They can form tumors and migrate to parts of the body where they don't belong.
For the study, the researchers scoured the Internet for businesses engaged in direct-to-consumer marketing of stem-cell procedures. Many of the clinics were in California (113), Florida (104) and Texas (71). Certain cities, including Beverly Hills, New York and San Antonio, were "hot spots." Almost two-thirds of the businesses offered procedures involving stem cells derived from a patient's own fat; almost half performed treatments using bone marrow.
The Food and Drug Administration has approved only a few stem-cell treatments. In the vast majority of cases, the procedures being conducted in the clinics are not approved, are outside clinical trials and can cost patients thousands of dollars.
The new analysis comes as the debate over regulating stem-cell clinics is intensifying. While some critics say the FDA should crack down on the industry, others say the clinics shouldn't face new restrictions because what they are doing is part of the "practice of medicine."
Michael Werner, executive director of the Alliance for Regenerative Medicine, which represents companies, patient advocates and researchers, said his group thinks FDA oversight is critical. He said "the proliferation of the so-called stem-cell clinics is potentially harmful because the treatments may not undergo, or have not undergone, the appropriate scientific rigor that takes place in evaluating new technologies and new medical treatments."
But Marc Scheineson, a former top FDA official who advises the Bipartisan Policy Center on medical innovation, said the current FDA regulatory regime is "archaic" and is stifling medical innovation.
Some Republicans in Congress are pushing a bill that would allow the FDA to approve stem-cell treatments for five years without advanced clinical trials.
As the issue heats up, the FDA has scheduled two public meetings in September to get public comment on draft guidance language on stem cells.
In a statement, the agency said, "In theory, stem cells may advance the treatment of many other diseases or conditions; however, at this time, the value of stem cells as a treatment for most conditions is largely unproven and more information is needed about their potential benefits."
The agency added that it is "concerned that the hope patients have for treatments not yet proven to be safe and effective may leave them vulnerable to unscrupulous providers of stem cell treatments that are illegal and potentially harmful."