title: Therapeutic factor VIII levels and negligible toxicity in mouse and dog models of hemophilia A following gene therapy with high-capacity adenoviral vectors.
abstract: High-capacity adenoviral (HC-Ad) vectors expressing B-domain-deleted human or canine factor VIII from different liver-specific promoters were evaluated for gene therapy of hemophilia A. Intravenous administration of these vectors into hemophilic FVIII-deficient immunodeficient SCID mice (FVIIIKO-SCID) at a dose of 5 x 10(9) infectious units (IU) resulted in efficient hepatic gene delivery and long-term expression of supraphysiologic FVIII levels (exceeding 15 000 mU/mL), correcting the bleeding diathesis. Injection of only 5 x 10(7) IU still resulted in therapeutic FVIII levels. In immunocompetent hemophilic FVIII-deficient mice (FVIIIKO), FVIII expression levels peaked at 75 000 mU/mL but declined thereafter because of neutralizing anti-FVIII antibodies and a cellular immune response. Vector administration did not result in thrombocytopenia, anemia, or elevation of the proinflammatory cytokine interleukin-6 (IL-6) and caused no or only transient elevations in serum transaminases. Following transient in vivo depletion of macrophages before gene transfer, significantly higher and stable FVIII expression levels were observed. Injection of only 5 x 10(6) HC-Ad vectors after macrophage depletion resulted in long-term therapeutic FVIII levels in the FVIIIKO and FVIIIKO-SCID mice. Intravenous injection of an HC-Ad vector into a hemophilia A dog at a dose of 4.3 x 10(9) IU/kg led to transient therapeutic canine FVIII levels that partially corrected whole-blood clotting time. Inhibitory antibodies to canine FVIII could not be detected, and there were no signs of hepatotoxicity or of hematologic abnormalities. These results contribute to a better understanding of the safety and efficacy of HC-Ad vectors and suggest that the therapeutic window of HC-Ad vectors could be improved by minimizing the interaction between HC-Ad vectors and the innate immune system.
authors.affiliation: Center for Transgene Technology and Gene Therapy, Flanders Interuniversity Institute for Biotechnology, University of Leuven, Belgium.
authors.forename: Marinee K L
authors.initials: MK
authors.lastname: Chuah
authors.forename: Gudrun
authors.initials: G
authors.lastname: Schiedner
authors.forename: Lieven
authors.initials: L
authors.lastname: Thorrez
authors.forename: Brian
authors.initials: B
authors.lastname: Brown
authors.forename: Marion
authors.initials: M
authors.lastname: Johnston
authors.forename: Veerle
authors.initials: V
authors.lastname: Gillijns
authors.forename: Sabine
authors.initials: S
authors.lastname: Hertel
authors.forename: Nico
authors.initials: N
authors.lastname: Van Rooijen
authors.forename: David
authors.initials: D
authors.lastname: Lillicrap
authors.forename: Désiré
authors.initials: D
authors.lastname: Collen
authors.forename: Thierry
authors.initials: T
authors.lastname: VandenDriessche
authors.forename: Stefan
authors.initials: S
authors.lastname: Kochanek
mesh_terms: D000260:Adenoviruses, Human / Q000235:genetics*; D000818:Animals; D000910:Antibodies, Heterophile / Q000096:biosynthesis / Q000276:immunology; D053304:Apolipoprotein C-II; D001056:Apolipoproteins C / Q000235:genetics; D001057:Apolipoproteins E / Q000235:genetics; D004002:Clodronic Acid / Q000494:pharmacology; D004274:DNA, Recombinant / Q000032:analysis / Q000235:genetics; D004283:Dog Diseases / Q000235:genetics / Q000628:therapy; D004285:Dogs; D005169:Factor VIII / Q000032:analysis* / Q000235:genetics / Q000276:immunology; D005813:Genes, Synthetic; D015316:Genetic Therapy; D005822:Genetic Vectors / Q000008:administration & dosage / Q000235:genetics / Q000627:therapeutic use*; D006467:Hemophilia A / Q000097:blood / Q000235:genetics / Q000628:therapy* / Q000662:veterinary; D006470:Hemorrhage / Q000517:prevention & control; D007275:Injections, Intravenous; D008099:Liver / Q000378:metabolism; D008111:Liver Function Tests; D008264:Macrophages / Q000187:drug effects / Q000502:physiology; D051379:Mice; D016688:Mice, Inbred NOD; D018345:Mice, Knockout; D016513:Mice, SCID; D023421:Models, Animal; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000096:biosynthesis; D013045:Species Specificity
chemical_list: D000910:Antibodies, Heterophile; D053304:Apolipoprotein C-II; D001056:Apolipoproteins C; D001057:Apolipoproteins E; D004274:DNA, Recombinant; D012333:RNA, Messenger; D004002:Clodronic Acid; D005169:Factor VIII