By Pat Anson, PNN Editor

A new study is warning patients and healthcare providers of possible bacterial contamination and other serious risks in “unproven” stem cell products being marketed as treatments for chronic pain, arthritis and other medical conditions.   

The study findings, published in JAMA Network Open, are the outcome of an investigation that began in 2018 after public health officials began receiving reports of bacterial infections in stem cell patients. At least 20 patients in eight states developed serious infections after receiving stem cells derived from umbilical cord blood.

All of the infections were traced back to a single stem cell manufacturing lab in California, where over half the samples tested by the CDC were found to be infected with E coli and other bacteria. The contaminated products were recalled and the lab was ordered to improve its infection control procedures, but researchers say the risk of another outbreak remains.

“The findings from this outbreak underscore that unapproved and unproven stem cell products can expose patients to serious risks without clear benefit, including the possibility of product contamination,” wrote lead author Kiran Perkins, MD, an epidemiologist at the CDC Division of Healthcare Quality Promotion. “Patients and health care practitioners who are considering the use of unapproved products marketed as stem cell treatment should be aware of their unproven benefits and potential risks, including serious infections.”

The only stem cell products that are currently approved by the Food and Drug Administration are derived from umbilical cord blood, which are used to treat sickle cell disease and some cancers.

Despite FDA threats to crackdown on unproven stem cell treatments, over a thousand clinics have opened around the country, promoting stem cell injections and infusions to treat a wide variety of diseases and injuries. Many use stem cell products derived from a patient’s own body tissue – such as fat or bone marrow -- which clinic operators don’t consider a “drug” that falls under FDA jurisdiction.

Researchers say the clinics are taking advantage of desperate patients who want quick solutions to complex medical problems.

“Hundreds of clinics across the US unlawfully advertise stem cell treatments to patients as a cure for a variety of conditions for which there are currently no effective medical treatments, including certain neurological disorders, autism, and aging. Although some patients may be willing to risk unproven stem cell treatment over surgery for conditions such as chronic pain and degenerative joint diseases, this investigation demonstrates the potential risk associated with the use of these products,” Perkins and her colleagues wrote.

“Manufacturers of unlicensed products, such as those associated with this outbreak, violate the law for profit at the expense of public health. Many create market confusion by erroneously describing their products as novel therapies that do not require FDA premarketing review or approval. That is not the case.”

Of course, just because a treatment is unapproved or unlicensed doesn’t mean it’s ineffective. There are numerous examples of stem cells being used successfully to treat serious neurological conditions such as arachnoiditis and paralysis. Professional athletes have also embraced stem cells and platelet injections as therapies for stubborn muscle and joint injuries, often traveling overseas for treatments they can’t get in the U.S.

The FDA has been slow to take action against stem cell clinics and manufacturers, due in part to a “grace period” the agency adopted in 2017 to give them more time to submit new drug applications for FDA review. The grace period ended in May 2021, with no indication that many stem cell providers took the agency up on its offer.      

A recent report from the Pew Charitable Trust identified 360 patients who had adverse events involving stem cells over a 17-year period. While that pales in comparison to the number of Americans who die every year from medical errors -- over 250,000 --  Pew said it was time for “increased FDA enforcement action” against stem cell clinics.