Correction of Murine Hemophilia A and Immunological Differences of Factor VIII Variants Delivered by Helper-dependent Adenoviral Vectors

Bioengineering of the factor VIII (FVIII) molecule has led to the production of variants that overcome poor secretion and/or rapid inactivation. We tested six modified FVIII variants for in vivo efficacy by expressing them from helper-dependent adenoviral (HD-Ad) vectors. We constructed a wild-type...

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Bibliographic Details
Published in:Molecular therapy 2007-12, Vol.15 (12), p.2080-2087
Main Authors: Cerullo, Vincenzo, Seiler, Michael P, Mane, Viraj, Cela, Racel, Clarke, Christian, Kaufman, Randal J, Pipe, Steven W, Lee, Brendan
Format: Article
Language:English
Subjects:
Adenoviridae - genetics
Animals
Bioengineering
Drug dosages
Factor VIII - genetics
Factor VIII - immunology
Factor VIII - therapeutic use
Gene therapy
Genetic Engineering
Genetic Vectors
HeLa Cells
Hemophilia
Hemophilia A - therapy
Humans
Immunology
Mice
Phenotype
Protein expression
Proteins
Toxicity
Vectors (Biology)
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Summary:Bioengineering of the factor VIII (FVIII) molecule has led to the production of variants that overcome poor secretion and/or rapid inactivation. We tested six modified FVIII variants for in vivo efficacy by expressing them from helper-dependent adenoviral (HD-Ad) vectors. We constructed a wild-type (WT) variant, a B-domain-deleted (BDD) variant, a point mutant for improved secretion (F309S), a variant with a partial B-domain deletion for improved secretion (N6), a combination of the point mutant and partial BDD variant (F309N6), and an inactivation-resistant (IR8) FVIII variant. All the constructs expressed functional protein after injection of high-dose HD-Ad. Activity ranged from 20 to 50% with WT, to ∼100% with the N6 and F309N6 variants. Interestingly, mice treated with N6 showed long-term FVIII activity and phenotypic correction for up to 74 weeks, with low anti-FVIII antibody titer. Importantly, the N6 variant was therapeutically efficacious even after a 50% reduction of viral dose, thereby indicating that transgene modification itself can improve the dose efficacy of HD-Ad. This finding is significant, because dose efficacy is a key factor in clinical application. In summary, bioengineering of the FVIII molecule may be an effective approach to improving the safety, immunogenicity, and efficacy of HD-Ad gene therapy in hemophilia A (HA).
ISSN:1525-0016
1525-0024
DOI:10.1038/sj.mt.6300308