Sustained phenotypic correction of canine hemophilia A using an adeno-associated viral vector.
Gene therapy for hemophilia A requires efficient delivery of the factor VIII gene and sustained protein expression at circulating levels of at least 1% to 2% of normal. Adeno-associated viral type 2 (AAV2) vectors have a number of advantages over other viral vectors, including an excellent safety profile and persistent gene expression. However, a major disadvantage is their small packaging capacity, which has hampered their use in treating diseases such as hemophilia A, cystic fibrosis, and muscular dystrophy, which are caused by mutations in large genes. Here we demonstrate that this can be overcome by using small regulatory elements to drive expression of a B-domain-deleted form of FVIII. The use of this vector for hepatic gene transfer in a canine model of hemophilia A resulted in the sustained (> 14 months) expression of biologically active FVIII. FVIII activity levels of 2% to 4% were achieved. These levels correlated with a partial correction in the whole-blood clotting time and cuticle bleeding time. In addition, immunoprecipitation analysis demonstrated the expression of canine FVIII of the predicted size in the plasma of injected animals. These data support the use of AAV2 vectors in human clinical trials to treat hemophilia A patients.
Scallan
Ciaran D
CD
Avigen, Inc., 1201 Harbor Bay Parkway, Alameda, CA 94502.
Lillicrap
David
D
Jiang
Haiyan
H
Qian
Xiaobing
X
Patarroyo-White
Susannah L
SL
Parker
Amy E
AE
Liu
Tongyao
T
Vargas
Joseph
J
Nagy
Dea
D
Powell
Sharon K
SK
Wright
J Fraser
JF
Turner
Patricia V
PV
Tinlin
Shawn J
SJ
Webster
Sandra E
SE
McClelland
Alan
A
Couto
Linda B
LB
D000256:Adenoviridae / Q000235:genetics*; D000818:Animals; D006528:Carcinoma, Hepatocellular; D004195:Disease Models, Animal; D004285:Dogs; D005169:Factor VIII / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D015967:Gene Expression Regulation, Viral; D015316:Genetic Therapy / Q000379:methods*; D006467:Hemophilia A / Q000628:therapy*; D006801:Humans; D008099:Liver / Q000502:physiology; D008113:Liver Neoplasms; D010641:Phenotype; D017434:Protein Structure, Tertiary; D014407:Tumor Cells, Cultured
D005169:Factor VIII