P01HL160472

Toward Safer Gene Therapy for Hemophilia A - Project Summary

Abstract

Gene therapy for the X-linked bleeding disorder hemophilia holds much promise to accomplish a lasting cure. Four clinical trials utilizing adeno-associated viral (AAV) gene transfer to the livers of males with severe hemophilia are currently being investigated in multiple Phase III clinical trials. Hemophilia A (deficiency in Factor VIII, FVIII), the more common form of the disease (~80% of patients), has traditionally been more difficult to treat by gene therapy because FVIII is a large molecule and not efficiently expressed and secreted.

Nonetheless, initial results demonstrated complete correction of the disease. However, FVIII levels declined substantially over time, raising worrying questions about durability, and patients also experienced prolonged mild hepatotoxicity despite steroid drug treatment during the first year of gene therapy. Multiple recent observations raise serious questions about the safety of hepatic gene therapy for hemophilia A. These urgently need to be addressed so that this promising approach can be safely applied to patients and to achieve sustained correction.

For instance, the reasons for hepatotoxicity and for the decline in FVIII expression are unclear, highlighting critical gaps in our knowledge of the interactions between the vector and hepatocytes and between the FVIII expression and hepatocytes, as well as the role of the immune system in long-term outcome. There is also renewed concern about insertional mutagenesis. We will address these basic and mechanistic questions related to the biology of AAV and FVIII.

The central hypothesis of this proposal is that multiple interconnected features of AAV and FVIII biology limit durability of therapeutic expression and pose serious safety concerns. Further, we postulate that unraveling these mechanisms will allow for design of vectors and protocols that minimize these problems, thus resulting in lasting therapy and enhanced safety.

The program combines expertise in FVIII biology, cellular stress responses, immunology, and AAV vector biology and is structured into 3 scientific projects, an administrative core, and 2 scientific cores.

Project 1 (Kaufman) seeks to overcome FVIII protein misfolding and cell toxicity.

Project 2 (Xiao) will uncover the mechanisms that lead to formation of subgenomic AAV vector particles that form during vector production through nuclease and recombination activities.

Project 3 (Herzog) will define the mechanisms of innate and adaptive immune responses to AAV-FVIII gene transfer.

The objectives of the three projects will be supported by an administrative core (Core A), a core that provides human hepatocytes for in vitro and in vivo studies (Core B), and a core that performs development and molecular analysis of AAV vectors (Core C).

Overall, this project applies the expertise of the individual investigators towards addressing major unanswered questions in FVIII biology, gene therapy for hemophilia, liver-directed gene transfer, and molecular and immunobiology of AAV vectors.

Trustees Of Indiana University

THE DIVISION OF BLOOD DISEASES AND RESOURCES SUPPORTS RESEARCH AND RESEARCH TRAINING ON THE PATHOPHYSIOLOGY, DIAGNOSIS, TREATMENT, AND PREVENTION OF NON-MALIGNANT BLOOD DISEASES, INCLUDING ANEMIAS, SICKLE CELL DISEASE, THALASSEMIA, LEUKOCYTE BIOLOGY, PRE-MALIGNANT PROCESSES SUCH AS MYELODYSPLASIA AND MYELOPROLIFERATIVE DISORDERS, HEMOPHILIA AND OTHER ABNORMALITIES OF HEMOSTASIS AND THROMBOSIS, AND IMMUNE DYSFUNCTION. FUNDING ENCOMPASSES A BROAD SPECTRUM OF HEMATOLOGIC INQUIRY, RANGING FROM STEM CELL BIOLOGY TO MEDICAL MANAGEMENT OF BLOOD DISEASES AND TO ASSURING THE ADEQUACY AND SAFETY OF THE NATION'S BLOOD SUPPLY. PROGRAMS ALSO SUPPORT THE DEVELOPMENT OF NOVEL CELL-BASED THERAPIES TO BRING THE EXPERTISE OF TRANSFUSION MEDICINE AND STEM CELL TECHNOLOGY TO THE REPAIR AND REGENERATION OF HUMAN TISSUES AND ORGANS. SMALL BUSINESS INNOVATION RESEARCH (SBIR) PROGRAM: TO STIMULATE TECHNOLOGICAL INNOVATION, USE SMALL BUSINESS TO MEET FEDERAL RESEARCH AND DEVELOPMENT NEEDS, FOSTER AND ENCOURAGE PARTICIPATION IN INNOVATION AND ENTREPRENEURSHIP BY SOCIALLY AND ECONOMICALLY DISADVANTAGED PERSONS, AND INCREASE PRIVATE-SECTOR COMMERCIALIZATION OF INNOVATIONS DERIVED FROM FEDERAL RESEARCH AND DEVELOPMENT FUNDING. SMALL BUSINESS TECHNOLOGY TRANSFER (STTR) PROGRAM: TO STIMULATE TECHNOLOGICAL INNOVATION, FOSTER TECHNOLOGY TRANSFER THROUGH COOPERATIVE R&D BETWEEN SMALL BUSINESSES AND RESEARCH INSTITUTIONS, AND INCREASE PRIVATE SECTOR COMMERCIALIZATION OF INNOVATIONS DERIVED FROM FEDERAL R&D.

93.837 - Cardiovascular Diseases Research

National Heart Lung and Blood Institute (NHLBI) [HHS - NIH]

Indianapolis, Indiana 462025254 United States

Single Zip Code

NHLBI Program Project Applications (P01 Clinical Trials Optional) (PAR-21-088)

Amendment Since initial award the total obligations have increased 295% from $2,572,180 to $10,150,112.