Americans seeking stem cell replacement therapy hope the process can heal them of myriad diseases, and a 2011 report by the Baker Institute estimated the industry could bring in $16 billion in revenue by 2020.

But the Food and Drug Administration has expressed concerns. The agency sued to stop treatments at a Regenerative Sciences clinic in Colorado and closed the lab of another company, Celltex Therapeutics, in Texas.

While patients in dire situations are willing to try the therapy (and pay the hefty costs), there's concern the research doesn't support broad practice just yet.

Running Out Of Options

SammyJo Wilkinson remembers the day 18 years ago when she suddenly couldn't stand. She was a young, ambitious computer programmer, launching an Internet startup.

Her doctor told her it was secondary progressive multiple sclerosis.

Now, at 48, Wilkinson is in a wheelchair. She's tried every available FDA-approved drug and two experimental therapies, including a two-year course of chemotherapy. Nothing worked.

Over time, she started researching adult stem cell replacement, but it was available only abroad. The U.S. opened its doors to the treatment two years ago.

Wilkinson had to see a doctor first, but then she paid Celltex $28,000 for stem cell replacement. In a nutshell, the company promises to remove good, healthy stem cells; store them; make more; and put them back into her body where they can help her heal.

Wilkinson tells NPR's Laura Sullivan she got better immediately — 11 of her 25 MS-related symptoms have either improved or completely disappeared.

Last October, she was scheduled to have her second round of treatment, but then the FDA shut down the Celltex lab.

The Dispute

Journalist Susan Berfield investigated the FDA's case against Celltex for Bloomberg Businessweek.

"What the FDA said is what Celltex does to the stem cells is more than 'minimally manipulated,' which means that when they put the stem cells in that medium, they're doing something to it, and that process needs to be regulated," she tells Sullivan.

She says that what Celltex argues is that what it offers should be considered a medical procedure, rather than a product or drug (which would have to be approved and regulated by the FDA).

"But the FDA wasn't satisfied that what Celltex was promising the patients is what the patients were getting," Berfield says.

Andrea Ferrenz, executive vice president and legal counsel for Celltex, says the company is not selling a cure to sick people. She says the company provides treatment only when doctors request the company's services for their patients.

One of the doctors who refers patients is Celltex co-founder Stanley Jones. Ferrenz says this is not a conflict and that Jones is one of many doctors who want their patients to undergo adult stem cell replacement. He is also a patient himself for his arthritis.

The company is keeping a research arm open in the United States, but the profit-making part of the company is headed to Mexico, Ferrenz says, where it's opening a new clinic to expand the growing business.

"COFEPRIS, Mexico's equivalent of the FDA, is as concerned with safety for the people in its country as the U.S. FDA," she says.

Analyzing The Data

Ferrenz cites studies the company has done and some independent research that suggests the treatments are effective. But many scientists disagree. Among the skeptics is Dr. George Daley, who works at Boston Children's Hospital and is a founder of the Harvard Stem Cell Institute.

"There's a lot of promise, but we are still in the earliest experimental stages. The data, even in animals, has been highly variable," he says. "Certainly, we don't have convincing, compelling evidence that these cells work in humans, certainly not for the vast array of diseases that seem to be being treated at this time."

Daley says the therapy does have a lot of promise, though. It's even used at Children's Hospital, but only with certain cancers and diseases doctors are sure it treats.

Daley says stem cell therapy could become an everyday practice in a few decades.

"We need decades to learn how to harness the healing power of stem cells," he says.

No Time Left

For MS patients like Wilkinson, the future may be too far away.

"I don't have time," she says. "I'm completely out of time."

Wilkinson recognizes that the FDA has to do its job and that Celltex has to protect itself as well. But, she says, in the end, there will only be one loser in this fight over stem cells.

"[My husband and I have] decided ... through endless hours of discussion that this is the best investment we can make to improve both our lives," she says. "We're always just waiting in hope."

That's exactly what critics of these companies are worried about.

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