ABSTRACT
Labeled cells of various lineages have been used clinically for some years, but the capacity of stem cells for self-renewal, their robust proliferative potential, and their ability to differentiate into varied, disparate tissue phenotypes in response to appropriate biologic cues set them apart. This chapter summarizes the regulatory framework under which labeled stem cells might be used. The opinions are somewhat speculative as although the regulatory authorities have published extensively on the regulation of somatic cell therapies, and some (mainly hematopoietic) stem cell therapies are of considerable vintage, it does not appear that an imageable stem cell Investigational New Drug (IND) application has been formally presented to the Food and Drug Administration (FDA) or other authorities to test the system. As such, a more cautious approach has been taken. Most emphasis is on the regulatory environment in the United States; but as harmonization progresses, there is less difference between the various jurisdictions. Along with the regulatory aspects, this chapter expands on some of the pharmacology/toxicology issues that should be considered.
