Dr. Scott Gottlieb, the FDA commissioner, and Dr. Peter Marks, director of the FDA's Center for Biologics Evaluation and Research, co-authored a new paper detailing the delicate balance between safety and innovation when it comes to the possibilities of using stem cells in medicine.

"However, despite the increasingly widespread use of stem cells in techniques being labeled as regenerative medicine, clinical benefit has not been clearly shown in most instances," Gottlieb and Marks wrote.

The FDA hopes to change that, while continuing efforts to regulate the industry.

"The FDA seems to be saying they want to find a sweet spot of stem cell oversight where they encourage innovation by good citizens and yet also carefully regulate this sphere as well as encouraging those interested in transplanting stem cells into patients to work with the FDA," he said.

Although Gottlieb and Marks didn't mention clinics in their paper, they noted that facilitating the availability of safe and effective therapies was part of the FDA's oversight of regenerative medicine products, including new stem cell therapies.

The FDA will provide tools to encourage individual or small groups of physicians to collaborate in support of the development of a stem cell or other regenerative medicine product, they wrote.

Gottlieb and Marks also said the FDA is encouraging investigators who are involved in such innovative product development to engage in dialogue with the agency early on in the research process.

"It feels like the FDA leadership is in essence telling them, 'Do the right thing, and we'll help you with a trial, even if you aren't a big university or company,' " Knoepfler said. "It's reassuring to see though that the FDA still emphasizes it is crucial to have data and follow the rules."

The ability to make such predictions could be a big step toward getting safe and effective FDA-approved treatments to patients in the future.

For many investigational stem cell-based products, it remains unclear whether the measurements currently used to characterize products will predict their clinical effectiveness, according to the FDA.

As of now, stem cell-based products submitted to the FDA in clinical trial proposals are characterized using a small number of cell surface markers and simple measures of cell product activity -- but is that enough to truly predict clinical outcomes?

"We can use some of this information to help generate standards in this field," he said. "There is a tremendous amount of interest now in developing standards that will facilitate the development of regenerative medicine and products."

All in all, "combined with the publication today of New England Journal of Medicine article, the FDA wants to assure that developers of regenerative medicine therapies understand the regulatory pathways that are available," the agency said in a written statement emailed to CNN by a FDA spokesperson.

"The FDA is committed to ensuring that patients have access to safe and effective regenerative medicine products as efficiently as possible. We are also committed to making sure we take action against products being unlawfully marketed that pose a potential significant risk to their safety," the statement said.

"The agency has adopted a risk-based and science-based approach that builds upon existing regulations to support innovative product development while clarifying the FDA's authorities and enforcement priorities. This risk-based approach allows product developers time to engage with the FDA, to determine if they need to submit a marketing authorization application and, if so, submit their application to the FDA for approval," the statement said.

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Stem cell therapies: FDA sets a new path - CNN