In a message posted on Facebook in early May, a startup company in San Diego tried to sell a big batch of futuristic hope to those infected by COVID-19.

“Did you know that STEM CELLS can be administered intravenously and by inhalation through a nebulizer to treat lung damage caused by COVID-19 and other non-related lung conditions,” said the post from Brexo Bio.

The company supported this claim with a short video saying the treatment had succeeded with 73 coronavirus patients in the United Arab Emirates. For those interested in learning how to get even better treatments than those foreign therapies, Brexo Bio provided its phone number.

There’s only one catch: So far, no proven therapies exist for COVID-19.

Stem cell treatments offer tantalizing hope for the future. But such lofty claims are not out of character in the world of stem cell marketing, where hundreds of U.S. businesses offer remedies for various ailments, virtually all unproven by American scientific standards.

Since March, enforcement against stem cell-related firms has increased.

The U.S. Food and Drug Administration, which oversees the safety and effectiveness of new medicine, has sent at least five of them letters involving questionable coronavirus-related claims. The Federal Trade Commission, charged with protecting consumers from misleading advertising, also has issued at least eight warning letters about unsubstantiated stem-cell therapies for the virus.  

One FTC letter went to Brexo Bio on May 27. In it, the agency accused the company of unlawfully advertising that its services and products prevent or treat COVID-19. Those claims since have been removed from the website, which continues to offer access to other stem cell treatments in Mexico, where there are fewer legal restrictions for stem cell injections.

Brexo Bio has been run by BJ Retuya, a former sales director for another San Diego stem cell company, StemGenex, that filed for bankruptcy last year after the FDA accused it of illegally marketing an unapproved product to treat incurable diseases ranging from Alzheimer’s to rheumatoid arthritis.

The financial motive is powerful. Before it went bust amid legal trouble, StemGenex took in $4.4 million in gross revenue in 2017 and charged $14,900 per treatment, according to court records.

Retuya didn’t return messages seeking comment. In a YouTube video promoting Brexo Bio’s other stem cell services in March, he says, “we’re just trying to provide something else for the patient to give them hope and to give them better results.”

Without more oversight, opportunity looms large

Stem cell businesses are trying to take advantage of coronavirus fear by marketing unproven treatments, according to a peer-reviewed article earlier this month.

Author Leigh Turner, a bioethicist at the University of Minnesota, describes an anti-aging center near Los Angeles called Novus that was promoting “stem cell exosome” products it said might help with coronavirus pneumonia.

Novus CEO Stephanie Wolff, a physician’s assistant, said in a YouTube video dated March 29 that a study in China supported the firm’s claims.

To make it easy on the consumer, the product could be shipped to a client’s home delivered on dry ice with a vaporizer.

“It can only help,” said Wolff’s son, Austin, an actor who is also the firm’s director of research. He added a caveat: “There’s a chance that it won’t do anything for you.”

Exosomes – extracellular vesicles released from cells – also have been marketed as treatments for various health concerns, although no exosome products have been approved by the FDA. But no FDA or FTC enforcement action could be found against Novus and neither agency would comment, saying they typically don’t discuss possible enforcement cases. 

An employee who answered the phone last week said the company still offers the product and that it is “around $10,000 because you’re getting two vials of the stem cells.”

The marketing of stem cell exosome treatments for COVID-19 also was a focus of a warning letter from the FDA to EUCYT Laboratories in Las Vegas this month. 

On its website, EUCYT said its product “harnesses the power of the immune system to augment the body’s natural response to invading pathogens such as severe acute respiratory distress coronavirus.”

The company didn’t return a message seeking comment and was still marketing the product as of Monday. After an email inquiry from USA TODAY that same day, the product disappeared from the company’s website.

In April, the FDA put a New Jersey stem cell company on notice about questionable claims about cellular products on its Facebook page.

“With COVID-19 dominating the headlines, preventative measures are essential to maintaining a healthy immune system,” said the page of Regenerative Solutions of New Jersey. “MSC Exosomes have been shown to modulate the immune system to protect against coronavirus and other viruses.”

The Facebook post has been taken down from public view. A woman answering the phone at the company’s listed number on said the business no longer exists.

Stem cell treatment: `A different world than taking a pill’

The recent spate of FDA warning letters may be the most ever in such a short period of time, according to biologist Paul Knoepfler – and just a fraction of the companies he believes are not complying with the law by marketing unapproved treatments.

Knoepfler tracks the stem cell industry and conducts stem cell research at the University of California, Davis School of Medicine. He estimates there are about 1,000 stem cell clinics in the U.S., up from about 200 five years ago.

The FDA has not approved any stem-cell based products for use, except for cord-blood-derived blood-forming stem cells for certain indications, such as blood disorders.

“This is a different world than taking a pill, because if you take a pill, you can stop taking a pill,” Knoepfler told USA TODAY. “But if someone injects you with a billion living cells, some of those cells are never going away and you don’t really have control over them.” 

Experts say the FDA has taken a light approach to the direct-to-consumer stem cell industry, using its discretion to go after firms perceived to pose the biggest risks to patients in a game of enforcement whack-a-mole.

Last year, for example, the FDA won a court injunction against a Florida firm, U.S. Stem Cell, some of whose clients went blind after receiving fat-derived stem cell injections in their eyes to treat macular degeneration.

But the FDA said it has stepped up its enforcement in this relatively young field as it exploded in growth. The agency also has signaled it will get tougher after November, the end of a three-year period to comply with guidance it issued in 2017. Even stem cells that come from a patient’s own body will continue to be regulated by the FDA as experimental drugs if they are more than “minimally manipulated.”

“Once the enforcement discretion period has ended, for those marketing or offering for sale (a cellular product) that requires but lacks pre-market approval, they will do so at their own risk,” the FDA said in a statement. “In the meantime, the FDA will not shy away from taking action when we see bad actors taking advantage of patients, and putting them at risk, for their own financial profit.”

‘Easy to scam patients’

Stem cell business owners generally believe that the U.S. is too restrictive about experimental medicine that shows promise. They also often cite positive results, such as anecdotal examples of clients who believed the treatments worked.

Without more scientific testing – randomized, double-blind testing that controls for the placebo effect or other standards – nobody really knows how well they worked.

Turner, the bioethicist, said he doesn’t think U.S. regulatory standards are too high because “businesses ought to have convincing evidence of safety and efficacy before they advertise and administer stem cell treatments.”

“Selling such products on the basis of anecdotes isn’t enough,” Turner said.

He noted that many diseases are simply difficult to treat, adding that stem cell treatments are “a marketplace where it’s very easy to scam patients.”

Clinical studies involving stem cell treatments are underway in the U.S., but likely are several years and millions of dollars away from approval.

To make money in the meantime, some U.S. firms have created business models that involve sending patients to clinics in other countries, including Mexico, where some of the more aggressive experimental injections are allowed.

Retuya, who is not a doctor or scientist, apparently started Brexo Bio with this in mind after departing StemGenex, which sold fat-derived stem cell injections for patients in the U.S. StemGenex still faces a class-action lawsuit from consumers who said the company made dubious marketing claims.

“I felt that with this new business model (at Brexo Bio), we could remain a US based company but break free from the regulatory framework and restrictions here in the US,” Retuya said in a post on Instagram.

In the YouTube video from March, he that he’s seen “hundreds” of clients get results from these treatments but was careful to say they are not guaranteed or FDA-approved.

Follow reporter Brent Schrotenboer @Schrotenboer. E-mail: bschrotenb@usatoday.com