Article

Safety of AAV Factor IX Peripheral Transvenular Gene Delivery to Muscle in Hemophilia B Dogs

Division of Hematology and Center for Cellular and Molecular Therapeutics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, USA.
Molecular Therapy (Impact Factor: 6.43). 07/2010; 18(7):1318-29. DOI: 10.1038/mt.2010.73
Source: PubMed

ABSTRACT Muscle represents an attractive target tissue for adeno-associated virus (AAV) vector-mediated gene transfer for hemophilia B (HB). Experience with direct intramuscular (i.m.) administration of AAV vectors in humans showed that the approach is safe but fails to achieve therapeutic efficacy. Here, we present a careful evaluation of the safety profile (vector, transgene, and administration procedure) of peripheral transvenular administration of AAV-canine factor IX (cFIX) vectors to the muscle of HB dogs. Vector administration resulted in sustained therapeutic levels of cFIX expression. Although all animals developed a robust antibody response to the AAV capsid, no T-cell responses to the capsid antigen were detected by interferon (IFN)-gamma enzyme-linked immunosorbent spot (ELISpot). Interleukin (IL)-10 ELISpot screening of lymphocytes showed reactivity to cFIX-derived peptides, and restimulation of T cells in vitro in the presence of the identified cFIX epitopes resulted in the expansion of CD4(+)FoxP3(+)IL-10(+) T-cells. Vector administration was not associated with systemic inflammation, and vector spread to nontarget tissues was minimal. At the local level, limited levels of cell infiltrates were detected when the vector was administered intravascularly. In summary, this study in a large animal model of HB demonstrates that therapeutic levels of gene transfer can be safely achieved using a novel route of intravascular gene transfer to muscle.

Download full-text

Full-text

Available from: Daniel Hui, Oct 01, 2014
0 Followers
 · 
152 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Cellular immune responses to adeno-associated viral (AAV) vectors used for gene therapy have been linked to attenuated transgene expression and loss of efficacy. The impact of such cellular immune responses on the clinical efficacy of alipogene tiparvovec (Glybera®, AAV1-LPLS447X, uniQure, Amsterdam, the Netherlands), a gene-therapy consisting of intramuscular administration of a recombinant (r)AAV1 mediating muscle-directed expression of lipoprotein lipase (LPL), was investigated. Five subjects with LPL-deficiency (LPLD) were administered intramuscularly with a dose of 1 x 1012 gc/kg alipogene tiparvovec. All subjects were treated with immune suppression starting shortly before administration of alipogene tiparvovec and maintained until 12 weeks after administration. Systemic antibody and T cell responses against AAV1 and LPLS447X, as well as local cellular immune responses in the injected muscle were investigated in 5 LPLD subjects. Long term transgene expression was demonstrated despite a transient systemic cellular response and a stable humoral immune response against AAV1 capsid protein. Cellular infiltrates were found in 4 of the 5 subjects but were not associated with adverse clinical events or elevation of inflammation markers. Consistent herewith, CD8-positive T cells in the infiltrates lacked cytotoxic potential. Furthermore, FoxP3-positive/CD4-positive T cells were found in the infiltrates suggesting that multiple mechanisms contribute to local tolerance. Systemic and local immune responses induced by intramuscular injection of alipogene tiparvovec have no impact on safety and did not compromise LPL transgene expression. These findings support the use of alipogene tiparvovec in individuals with LPLD and indicate that muscle directed AAV-based gene therapy remains a promising approach for the treatment of human diseases.
    Human gene therapy 12/2013; 25(3). DOI:10.1089/hum.2013.169 · 3.62 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Adeno-associated viral (AAV) vector-mediated gene replacement for the treatment of muscular dystrophy represents a promising therapeutic strategy in modern medicine. One major obstacle in using AAV vectors for in vivo gene delivery is the development of host immune responses to the viral capsid protein and transgene products as evidenced in animal models and human trials for a range of genetic diseases. Here, we review immunity against AAV vector and transgene in the context of gene delivery specific to muscles for treating muscular dystrophies and non-muscle diseases in large animal models and human trials, factors that influence the intensity of the immune responses, and immune modulatory strategies to prevent unwanted immune responses and induce tolerance to the vector and therapeutic gene for a successful gene therapy.
    Frontiers in Microbiology 09/2011; 2:201. DOI:10.3389/fmicb.2011.00201 · 3.94 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Adeno-associated virus (AAV) vectors are platform of choice for in vivo gene transfer applications. However, neutralizing antibodies (NAb) to AAV can be found in humans and some animal species as a result of exposure to the wild-type virus, and high-titer NAb develop following AAV vector administration. In some conditions, anti-AAV Nab can block transduction with AAV vectors even when present at low titers, thus requiring prescreening prior to vector administration. Here we describe an improved in vitro, cell-based assay for the determination of NAb titer in serum or plasma samples. The assay is easy to setup and sensitive and, depending on the purpose, can be validated to support clinical development of gene therapy products based on AAV vectors.
    Human Gene Therapy Methods 03/2015; 26(2). DOI:10.1089/hgtb.2015.037 · 1.64 Impact Factor