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Engineering and Evolution of Synthetic Adeno-Associated Virus AAV Gene Therapy Vectors via DNA Family Shuffling
Published on: April 2, 2012
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Coagulation factor IX gene transfer to non-human primates using engineered AAV3 capsid and hepatic optimized
Sandeep R P Kumar1, Jun Xie2, Shilang Hu2
1Department of Pediatrics, Herman B Wells Center for Pediatric Research, Indiana University, Indianapolis, IN, USA.
Molecular Therapy. Methods & Clinical Development
|October 11, 2021
Summary
This study developed a novel adeno-associated viral vector (AAV3) for hemophilia B gene therapy. Low doses achieved normal factor IX levels in primates, supporting clinical use.
Area of Science:
- Gene Therapy
- Virology
- Hematology
Background:
- Adeno-associated viral (AAV) vectors show promise for hemophilia B gene therapy.
- AAV serotype 3 (AAV3) exhibits superior tropism for human hepatocytes.
- Developing alternative vector designs is crucial for advancing gene therapy.
Purpose of the Study:
- To develop and evaluate a novel AAV3-based vector for hepatic gene transfer in hemophilia B.
- To assess the efficacy and safety of a codon-optimized, CpG-depleted FIX-Padua gene in non-human primates.
- To investigate the impact of pre-existing neutralizing antibodies on gene transfer efficiency.
Main Methods:
- Constructed a clinical-grade AAV3 vector expressing hyperactive human coagulation factor IX (FIX)-Padua.
- Optimized the vector genome for hepatocyte-specific translation and reduced immunogenicity.
- Administered the vector via hepatic gene transfer in non-human primates at varying doses.
- Monitored FIX activity, neutralizing antibody levels, and cellular immune responses.
Main Results:
- A low vector dose (5 × 10^11 vg/kg) achieved FIX activity near normal levels.
- Pre-existing neutralizing antibodies partially or completely blocked gene transfer at low doses.
- No CD8+ T-cell response against the AAV3 capsid was detected.
- Antibodies against the FIX transgene formed at higher doses, but sustained FIX activity was observed in 2/3 animals.
Conclusions:
- The developed AAV3 vector shows potential for hemophilia B gene therapy at low doses.
- Pre-existing immunity is a significant factor influencing gene transfer efficacy.
- Further studies are warranted to optimize AAV vector delivery and overcome immune barriers in hemophilia B patients.
