title: AAV liver expression of FIX-Padua prevents and eradicates FIX inhibitor without increasing thrombogenicity in hemophilia B dogs and mice.
abstract: Emerging successful clinical data on gene therapy using adeno-associated viral (AAV) vector for hemophilia B (HB) showed that the risk of cellular immune response to vector capsid is clearly dose dependent. To decrease the vector dose, we explored AAV-8 (1-3 × 10(12) vg/kg) encoding a hyperfunctional factor IX (FIX-Padua, arginine 338 to leucine) in FIX inhibitor-prone HB dogs. Two naïve HB dogs showed sustained expression of FIX-Padua with an 8- to 12-fold increased specific activity reaching 25% to 40% activity without antibody formation to FIX. A third dog with preexisting FIX inhibitors exhibited a transient anamnestic response (5 Bethesda units) at 2 weeks after vector delivery following by spontaneous eradication of the antibody to FIX by day 70. In this dog, sustained FIX expression reached ∼200% and 30% of activity and antigen levels, respectively. Immune tolerance was confirmed in all dogs after challenges with plasma-derived FIX concentrate. Shortening of the clotting times and lack of bleeding episodes support the phenotypic correction of the severe phenotype, with no clinical or laboratory evidence of risk of thrombosis. Provocative studies in mice showed that FIX-Padua exhibits similar immunogenicity and thrombogenicity compared with FIX wild type. Collectively, these data support the potential translation of gene-based strategies using FIX-Padua for HB.
authors.affiliation: Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA;
authors.forename: Julie M
authors.initials: JM
authors.lastname: Crudele
authors.affiliation: Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA;
authors.forename: Jonathan D
authors.initials: JD
authors.lastname: Finn
authors.affiliation: Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA;
authors.forename: Joshua I
authors.initials: JI
authors.lastname: Siner
authors.affiliation: Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA;
authors.forename: Nicholas B
authors.initials: NB
authors.lastname: Martin
authors.affiliation: Department of Biochemistry, University of Alabama at Birmingham, Birmingham, AL; and.
authors.forename: Glenn P
authors.initials: GP
authors.lastname: Niemeyer
authors.affiliation: Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA;
authors.forename: Shangzhen
authors.initials: S
authors.lastname: Zhou
authors.affiliation: Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA;
authors.forename: Federico
authors.initials: F
authors.lastname: Mingozzi
authors.affiliation: Department of Biochemistry, University of Alabama at Birmingham, Birmingham, AL; and.
authors.forename: Clinton D
authors.initials: CD
authors.lastname: Lothrop
authors.affiliation: Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA; Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA.
authors.forename: Valder R
authors.initials: VR
authors.lastname: Arruda
mesh_terms: D019943:Amino Acid Substitution; D000818:Animals; D002213:Capsid / Q000276:immunology; D016207:Cytokines / Q000097:blood; D000229:Dependovirus / Q000235:genetics / Q000276:immunology; D004195:Disease Models, Animal; D004285:Dogs; D005164:Factor IX / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000276:immunology / Q000627:therapeutic use; D015870:Gene Expression; D015316:Genetic Therapy / Q000379:methods*; D005822:Genetic Vectors / Q000009:adverse effects / Q000276:immunology; D002836:Hemophilia B / Q000235:genetics* / Q000628:therapy*; D006801:Humans; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008817:Mice, Mutant Strains; D050505:Mutant Proteins / Q000235:genetics / Q000276:immunology / Q000627:therapeutic use; D011994:Recombinant Proteins / Q000235:genetics / Q000276:immunology / Q000627:therapeutic use; D013927:Thrombosis / Q000517:prevention & control; D057170:Translational Research, Biomedical
chemical_list: D016207:Cytokines; D050505:Mutant Proteins; D011994:Recombinant Proteins; C000592235:factor IX-Padua; D005164:Factor IX