SUMMARYStem cell-based therapies hold tremendous promise for the treatment of serious diseases and injuries. Although hematopoietic stem cell transplantation is routinely used as part of the treatment regime for some malignancies and genetic diseases, most stem cell-based therapeutic products are investigational and still require preclinical and clinical studies to support their many novel therapeutic uses. Because of the multiple sources of stem cells, the plethora of potential applications, and the novel mechanism of action of stem cell-based therapies, there is no single set of universal guidance documents that can be used to inform the preclinical development path for these therapeutics. Specific technical issues relating to the transplantation of human cells in animals, new delivery procedures, and laborious methods to characterize transplanted cells can present further challenges in the design and execution of preclinical animal studies for stem cell-based therapeutic products. In this article, we outline important parameters to guide the design of preclinical studies for stem cell-based therapeutics. In addition, we review the types of preclinical studies that should be considered depending on the nature and specific use of the intended stem cell therapeutic product. Finally, we describe important considerations in the design and execution of specific studies to monitor the efficacy, toxicity, biodistribution, and tumorigenicity of stem cell-based therapeutics. STEM CELLS TRANSLATIONAL MEDICINE 2012;1:353-358

A workshop addressing regulation of clinical implementation of stem cell therapies preceded the ISSCR 8th Annual Meeting, cosponsored by the International Society for Stem Cell Research, the California Institute for Regenerative Medicine and the International Society for Cellular Therapy.

Cell therapies derived from pluripotent stem cells are entering the preclinical and early clinical development phase, but eventual translation faces many challenges. We describe a new approach by California to form global public-private "disease team" partnerships to enable new clinical opportunities to be evaluated in the complex regulatory environment.

production of cells that are to be used clinically will have to be provided when organizations seek regulatory approval. By contrast, patents provide transparency and thus facilitate competition and progress. The judgment refers only to ESCs, and a great deal of research is being carried out with other types of stem cells. A stated objective of Greenpeace UK is to bring pressure to increase research with alternatives to hESCs. There is no doubt that researchers do consider alternatives and that great interest is placed upon iPSCs. Patent applications made in the future can encompass both sources of pluripotent cells, but iPSCs are a relatively new invention, so early applications such as that made by Oliver Brü stle did not. It would be wasteful and it would delay treatment of patients if existing protocols for use of hESC derivatives are not taken to the clinic because the procedure cannot be patented. Finally, there is a real concern that Europe will be perceived as reactionary and resistant to progress in light of this regulation and that as a result, companies will choose to invest in other regions of the world. It is certainly to be hoped that this is not the case, because Europe has a fine record of research with both embryonic and tissue stem cells.

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