Primitive hematopoietic progenitor and stem cells have been pursued as
highly desirable targets for genetic therapy, Retroviral vectors have
been used for the majority of preclinical and clinical studies direct
ed at these cells; however, both preclinical and early clinical studie
s indicate that the gene transfer efficiency of the current generation
of vectors using known transduction conditions into primate and human
repopulating stem cells is too low to be of clinical utility in most
situations. In this presentation I will summarize the status of our co
mpleted and ongoing clinical genetic marking trials, and describe our
efforts in the laboratory and use of primate transplantation models to
improve on these results.