UMMS Affiliation

Horae Gene Therapy Center; Department of Microbiology and Physiological Systems; Li Weibo Institute for Rare Diseases Research

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Document Type



Congenital, Hereditary, and Neonatal Diseases and Abnormalities | Hemic and Lymphatic Diseases | Immunology and Infectious Disease | Molecular Biology | Therapeutics


Hepatic gene transfer with adeno-associated viral (AAV) vectors shows much promise for the treatment of the X-linked bleeding disorder hemophilia B in multiple clinical trials. In an effort to further innovate this approach and to introduce alternative vector designs with potentially superior features into clinical development, we recently built a vector platform based on AAV serotype 3 because of its superior tropism for human hepatocytes. A vector genome with serotype-matched inverted terminal repeats expressing hyperactive human coagulation factor IX (FIX)-Padua was designed for clinical use that is optimized for translation using hepatocyte-specific codon-usage bias and is depleted of immune stimulatory CpG motifs. Here, this vector genome was packaged into AAV3 (T492V + S663V) capsid for hepatic gene transfer in non-human primates. FIX activity within or near the normal range was obtained at a low vector dose of 5 x 10(11) vector genomes/kg. Pre-existing neutralizing antibodies, however, completely or partially blocked hepatic gene transfer at that dose. No CD8(+) T cell response against capsid was observed. Antibodies against the human FIX transgene product formed at a 10-fold higher vector dose, albeit hepatic gene transfer was remarkably consistent, and sustained FIX activity in the normal range was nonetheless achieved in two of three animals for the 3-month duration of the study. These results support the use of this vector at low vector doses for gene therapy of hemophilia B in humans.


AAV, adeno-associated virus, antibodies, capsid, factor IX, hemophilia, immune response, liver, non-human primate

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Copyright 2021 The Author(s). This is an open access article under the CC BY-NC-ND license (

DOI of Published Version



Kumar SRP, Xie J, Hu S, Ko J, Huang Q, Brown HC, Srivastava A, Markusic DM, Doering CB, Spencer HT, Srivastava A, Gao G, Herzog RW. Coagulation factor IX gene transfer to non-human primates using engineered AAV3 capsid and hepatic optimized expression cassette. Mol Ther Methods Clin Dev. 2021 Aug 26;23:98-107. doi: 10.1016/j.omtm.2021.08.001. PMID: 34631930; PMCID: PMC8476648. Link to article on publisher's site

Journal/Book/Conference Title

Molecular therapy. Methods and clinical development

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Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.