Differing U.S. standards stymie stem-cell research

By Kim Blakeley

NIH, FDA policies appear to make most federally funded embryonic stem cell lines unsuitable for clinical use

Since the discovery of human embryonic stem cells, scientists have had high hopes for their use to treat a wide variety of diseases. In 2009 the National Institutes of Health established funding guidelines for research that dictate that human stem cells be derived only from embryos “created using in vitrofertilization for reproductive purposes… and no longer needed for this purpose.”

By defining which embryos could be involved in research, the NIH also aimed to identify which stem-cell “lines” – propagated collections of genetically identical cells – are suitable for the NIH registry, and for public funding.

Separately, the U.S. Food and Drug Administration issued the “Tissue Donor Guidance” regarding the source of human tissues that could be used in therapeutic products. This guidance applies to embryonic stem cell lines.

It has become clear that the FDA’s guidance, in concert with the NIH stem-cell regulations, stymies scientists who seek to develop marketable products from embryonic stem-cell lines to treat patients with serious diseases.

Erica C. Jonlin, clinical research administrator and regulatory manager for the University of Washington’s Institute for Stem Cell and Regenerative Medicine, addresses this failure in a letter published Feb. 6 in Cell Stem Cell.

She outlines the disconnect:

The FDA regulates the development and marketing of therapeutic products for human use, including embryonic stem-cell‐derived products. The FDA’s mandate states that before human tissue is donated, the would‐be donor must be tested and proven to be negative/non‐reactive for a list of infectious agents/diseases – much in the same way blood donors are screened before their blood is drawn. But patients at fertility clinics are not routinely screened for all of these infectious agents identified by FDA regulations. Moreover, no FDA-licensed, approved or cleared screening tests exist for prions, the agent that causes human transmissible spongiform encephalopathy. Instead, the FDA calls for an extensive interview of would-be donors for possible exposure to prions. Unfortunately, fertility-clinic patients are not interviewed about this possibility.

The unintended consequence, Jonlin said, is that the vast majority of the human embryonic stem-cell lines made to date, and listed on the NIH Stem Cell Registry, do not meet the FDA’s requirements for source material for medical products.

Investigators in academia and industry alike are seeking guidance from U.S. regulatory authorities about how to move past this dilemma so that stem-cell technologies can be developed into products available to patients with serious diseases.