Technology evaluation: Stem-cell therapy, Aastrom Biosciences Inc.

The expansion of human stem cells and their genetic manipulation represent areas of increasing interest in the field of stem cell transplantation. Previously, stem cell transplantation has been accomplished by using cellular products obtained by large volume bone marrow or peripheral blood harvest. Difficulties with this approach include inadequate cell numbers and tumor cell contamination. Furthermore, for gene transfer modalities requiring proliferating progenitor cells, low gene expression would be expected in these products. To address these difficulties, the AastromReplicell System has been developed as a fully closed and automated system for expanding hematopoietic cells. Investigators at Aastrom have evaluated the conditions needed for optimal growth including the need for unpurified bone marrow or cord blood mononuclear cells, high cell densities, serum-containing medium and certain types of plastic surfaces. Studies have now been initiated to demonstrate the feasibility of generating enough cells to fully reconstitute hematopoiesis from small volumes of cellular progenitors. It has also been demonstrated that tumor cell contamination passively decreases during the culture period. It now remains to be shown in a direct comparison that this approach yields greater efficacy and a lower cost than transplantation with unmanipulated large volume marrow or peripheral blood stem cell products.