title: Sustained correction of FVII deficiency in dogs using AAV-mediated expression of zymogen FVII.
abstract: Factor VII (FVII) deficiency is a rare autosomal recessive bleeding disorder treated by infusion of fresh-frozen plasma, plasma-derived FVII concentrates and low-dose recombinant activated FVII. Clinical data suggest that a mild elevation of plasma FVII levels (>10% normal) results in improved hemostasis. Research dogs with a G96E missense FVII mutation (FVII-G96E) have <1% FVII activity. By western blot, we show that they have undetectable plasmatic antigen, thus representing the most prevalent type of human FVII deficiency (low antigen/activity). In these dogs, we determine the feasibility of a gene therapy approach using liver-directed, adeno-associated viral (AAV) serotype 8 vector delivery of a canine FVII (cFVII) zymogen transgene. FVII-G96E dogs received escalating AAV doses (2E11 to 4.95E13 vector genomes [vg] per kg). Clinically therapeutic expression (15% normal) was attained with as low as 6E11 vg/kg of AAV and has been stable for >1 year (ongoing) without antibody formation to the cFVII transgene. Sustained and supraphysiological expression of 770% normal was observed using 4.95E13 vg/kg of AAV (2.6 years, ongoing). No evidence of pathological activation of coagulation or detrimental animal physiology was observed as platelet counts, d-dimer, fibrinogen levels, and serum chemistries remained normal in all dogs (cumulative 6.4 years). We observed a transient and noninhibitory immunoglobulin G class 2 response against cFVII only in the dog receiving the highest AAV dose. In conclusion, in the only large-animal model representing the majority of FVII mutation types, our data are first to demonstrate the feasibility, safety, and long-term duration of AAV-mediated correction of FVII deficiency.
authors.affiliation: Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA;
authors.forename: Oscar A
authors.initials: OA
authors.lastname: Marcos-Contreras
authors.affiliation: Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA;
authors.forename: Shannon M
authors.initials: SM
authors.lastname: Smith
authors.affiliation: Department of Pathology and Laboratory Medicine and.
authors.forename: Dwight A
authors.initials: DA
authors.lastname: Bellinger
authors.affiliation: Department of Pathology and Laboratory Medicine and.
authors.forename: Robin A
authors.initials: RA
authors.lastname: Raymer
authors.affiliation: Department of Pathology and Laboratory Medicine and.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Merricks
authors.affiliation: Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA;
authors.forename: Armida
authors.initials: A
authors.lastname: Faella
authors.affiliation: Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA;
authors.forename: Giulia
authors.initials: G
authors.lastname: Pavani
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 Pathology and Laboratory Medicine and Department of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC;
authors.forename: Timothy C
authors.initials: TC
authors.lastname: Nichols
authors.affiliation: Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA; Howard Hughes Medical Institute and Raymond G. Perelman Center for Cellular and Molecular Therapeutics, The Children's Hospital of Philadelphia, Philadelphia, PA; and.
authors.forename: Katherine A
authors.initials: KA
authors.lastname: High
authors.affiliation: Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA; Raymond G. Perelman Center for Cellular and Molecular Therapeutics, The Children's Hospital of Philadelphia, Philadelphia, PA; and Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA.
authors.forename: Paris
authors.initials: P
authors.lastname: Margaritis
mesh_terms: D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D004285:Dogs; D005167:Factor VII / Q000235:genetics*; D005168:Factor VII Deficiency / Q000097:blood / Q000235:genetics* / Q000628:therapy*; D015870:Gene Expression; D015316:Genetic Therapy; D005822:Genetic Vectors / Q000008:administration & dosage / Q000235:genetics* / Q000627:therapeutic use*; D057809:HEK293 Cells; D006801:Humans; D017354:Point Mutation; D011498:Protein Precursors / Q000235:genetics*; D019076:Transgenes
chemical_list: D011498:Protein Precursors; C071874:prepro-factor VII; D005167:Factor VII