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Blood, 16 July 2009, Vol. 114, No. 3, pp. 526-534. Prepublished online as a Blood First Edition Paper on May 21, 2009; DOI 10.1182/blood-2009-01-199653. This Article Full Text Full Text (PDF) Supplemental Methods and Figures All Versions of this Article: blood-2009-01-199653v1 114/3/526    most recent Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Rights and Permissions Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Google Scholar Articles by Ramezani, A. Articles by Hawley, R. G. PubMed PubMed Citation Articles by Ramezani, A. Articles by Hawley, R. G. Related Collections Transplantation Thrombosis and Hemostasis Gene Therapy Social Bookmarking                   What's this?  Previous Article  |  Table of Contents  |  Next Article  GENE THERAPY Correction of murine hemophilia A following nonmyeloablative transplantation of hematopoietic stem cells engineered to encode an enhanced human factor VIII variant using a safety-augmented retroviral vector Ali Ramezani1, and Robert G. Hawley1 1 Department of Anatomy and Regenerative Biology, The George Washington University Medical Center, Washington, DC Insertional mutagenesis by retroviral vectors is a major impediment to the clinical application of hematopoietic stem cell gene transfer for the treatment of hematologic disorders. We recently developed an insulated self-inactivating gammaretroviral vector, RMSinOFB, which uses a novel enhancer-blocking element that significantly decreases genotoxicity of retroviral integration. In this study, we used the RMSinOFB vector to evaluate the efficacy of a newly bioengineered factor VIII (fVIII) variant (efVIII)—containing a combination of A1 domain point mutations (L303E/F309S) and an extended partial B domain for improved secretion plus A2 domain mutations (R484A/R489A/P492A) for reduced immunogenicity—toward successful treatment of murine hemophilia A. In cell lines, efVIII was secreted at up to 6-fold higher levels than an L303E/F309S A1 domain–only fVIII variant (sfVIIIB). Most important, when compared with a conventional gammaretroviral vector expressing sfVIIIB, lower doses of RMSin-efVIII-OFB–transduced hematopoietic stem cells were needed to generate comparable curative fVIII levels in hemophilia A BALB/c mice after reduced-intensity total body irradiation or nonmyeloablative chemotherapy conditioning regimens. These data suggest that the safety-augmented RMSin-efVIII-OFB platform represents an encouraging step in the development of a clinically appropriate gene addition therapy for hemophilia A. CiteULike    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this? This article has been cited by other articles: D. W. Scott T regulatory cells turn on T regulatory cells Blood, November 5, 2009; 114(19): 3975 - 3976. [Full Text] [PDF]

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