SBIR-STTR Award

Adeno-associated virus (AAV) vectors have been successfully applied in clinical trials in patients with diverse disorders. Two AAV based gene therapy drugs have been recently approved by the FDA. Luxturna has been valued at $850,000 for a one-time treatment for a rare form of blindness and Zolgensma priced at $2,100,000 for spinal muscle atrophy. As such, AAV vector based gene therapy is an increasingly attractive market. Although successful in clinical studies, two concerns restrict broader AAV vector applications for patients requiring liver targeted AAV gene therapy following systemic administration: low human hepatocyte transduction and neutralizing antibody (Nab)-mediated inhibition of AAV transduction. Several approaches have been explored for AAV transduction enhancement or capsid Nab evasion. Engineering of the AAV capsid presents a very powerful and popular technology that has been extensively studied to develop novel AAV vectors for enhanced transduction in animal models or Nab escape in vitro. However, it has been demonstrated that the results from mouse experiments do not recapitulate those of large animals such as primates and dogs. Thus, the data for AAV variants generated in animal cells and organs may not translate into successful human applications. Recently, a mouse xenograft model with human hepatocytes has been used to develop human liver targeted AAV vectors for gene therapy. In our previous studies, we have successfully isolated several AAV mutants from the liver of chimeric mice with human hepatocyte xenografts in the presence of human Nabs (IVIG) using the AAV shuffled capsid library approach. Specifically, BDRK001 (AAV mutant LP2-10) demonstrated a much higher ability to evade Nabs than any other AAV serotypes or mutants. However, BDRK001 was not enhanced for transduction in human hepatocytes when compared to the best natural serotype. In this application, we will use rational design strategy to generate novel AAV capsids by variable region I (VRI) domain swapping of BDRK001 using natural serotypes or mutants with high human liver tropism. This panel will then be evaluated in chimeric mice for human hepatocyte transduction (Aim 1) and Nab evasion (Aim 2). Bedrock's long-term goal of this approach is low dose AAV gene therapy for the successful treatment of a variety of liver diseases, independent of the patient's Nab prevalence.

Public Health Relevance Statement:
Gene Therapy with adeno-associated virus (AAV) vector has shown promise in recent clinical trials, however, these trials are exclusively applied to the patients without AAV neutralizing antibodies. We will use the rational design to develop AAV mutants with the ability for both neutralizing antibody evasion and the human hepatocytes transduction enhancement. If success, these mutants can be immediately used to deliver therapeutic transgene for patients with neutralizing antibodies and requiring the liver targeting. Terms: Dependovirus; Adeno-Associated Viruses; Dependoparvovirus; adeno associated virus group; Affect; Albumins; Anatomy; Anatomic; Anatomic Sites; Anatomic structures; Anatomical Sciences; Animals; Biology; Blood Component Removal; Apheresis; Hemapheresis; Pheresis; Capsid; Cells; Cell Body; Clinical Research; Clinical Study; Clinical Trials; Mental Depression; depression; Disease; Disorder; Canis familiaris; Canine Species; Dogs; Dogs Mammals; canine; domestic dog; Pharmaceutical Preparations; Drugs; Medication; Pharmaceutic Preparations; drug/agent; Engineering; Flow Cytometry; Flow Cytofluorometries; Flow Cytofluorometry; Flow Microfluorimetry; Flow Microfluorometry; flow cytophotometry; gene therapy; DNA Therapy; Gene Transfer Clinical; Genetic Intervention; gene repair therapy; gene-based therapy; genetic therapy; genomic therapy; Goals; Human; Modern Man; Immunohistochemistry; Immunohistochemistry Cell/Tissue; Immunohistochemistry Staining Method; In Vitro; Industry; Infection; Libraries; Liver; hepatic body system; hepatic organ system; Liver diseases; Hepatic Disorder; hepatic disease; hepatopathy; liver disorder; Masks; Methods; mortality; Mus; Mice; Mice Mammals; Murine; Muscular Atrophy; Muscle Atrophy; muscle breakdown; muscle degradation; muscle deterioration; muscle loss; muscle wasting; Mutation; Genetic Alteration; Genetic Change; Genetic defect; genome mutation; Patients; Blood Plasma; Plasma Serum; Reticuloendothelial System, Serum, Plasma; Plasma; Play; Primates Mammals; Primates; Production; QOL; Quality of life; Investigators; Researchers; Research Personnel; social role; Role; Safety; Serotyping; Technology; Time; Tissues; Body Tissues; Traction; Virion; Virus Particle; Price; pricing; Intravenous Immunoglobulins; IGIV; IV Immunoglobulins; IVIG; Immune globulin IV; Intravenous Antibodies; Intravenous IG; Intravenous Immune Globulin; Mediating; base; Organ; Surface; Clinical; Phase; Variant; Variation; Hepatic Cells; Hepatic Parenchymal Cell; Liver Cells; Hepatocyte; Blood Serum; Serum; Tropism; directed evolution; Directed Molecular Evolution; Therapeutic; Investigation; Clinic; System; vision loss; visual loss; Blindness; neutralizing antibody; Heterograft; Heterologous Transplantation; Xenograft; Xenotransplantation; xeno-transplant; xeno-transplantation; Xenograft procedure; Spinal; American; mutant; success; Animal Models and Related Studies; model of animal; model organism; Animal Model; Orphan Disease; Rare Disorder; orphan disorder; Rare Diseases; novel; Property; cross reactivity; Molecular Interaction; Binding; Pharmaceutical Agent; Pharmaceuticals; Pharmacological Substance; Pharmacologic Substance; Dose; Data; High Prevalence; Gene Transduction Agent; Gene Therapy Vectors; Gene Transduction Vectors; Gene Transfer; Xenograft Model; xenograft transplant model; xenotransplant model; Preparation; Gene Delivery; Pathway interactions; pathway; vector; cost; virtual; Population; Prevalence; therapeutic transgene; adeno-associated viral vector; AAV vector; adeno-associated virus vector; FDA approved; efficacy testing; phase 2 study; phase II study; Mendelian disorder; Mendelian disease; Mendelian genetic disorder; monogenic disease; monogenic disorder; single-gene disease; single-gene disorder; humanized mouse; humanized mice; experimental study; experiment; experimental research; clinical development; Immunize; Genetic Diseases; genetic condition; genetic disorder; delivery vehicle; delivery vector; rational design