In vivo Sickle Cell Disease Gene Therapy Using a Novel Virus Like Particle

PROJECT SUMMARY Project Title: In vivo Sickle Cell Disease Gene Therapy Using a Novel Virus Like Particle Organization: GigaMune, Inc. PI: David S. Johnson, Ph.D. β-hemoglobinopathies are the most common monogenic disorders worldwide. These autosomal recessive disorders affect the normal production of adult hemoglobin due to mutations in the β-globin gene. The two most common diseases are: i) β-thalassemia, which is characterized by low or absent β-globin production, and ii) sickle cell disease (SCD), in which a mutant form of β-globin is produced that results in red blood cells (RBCs) shaped like “sickles” rather than the normal disc shape. Gene therapies could provide life-long cures for these patients. The FDA recently approved Zynteglo, an ex vivo manufactured cell-based gene therapy, for the treatment of β-thalassemia and is reviewing two ex vivo gene therapies (lovo-cel and exa-cel) for β-hemoglobinopathies. Ex vivo gene therapies for β-thalassemia and SCD remove hematopoietic stem cells (HSCs) from patients, edit the HSCs using lentiviral transgene delivery or Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)/Cas gene editing, and infuse the cells back into patients, with the goal of long-term production of healthy erythrocytes. In vivo gene therapies are more accessible because they can be administered at most hospitals, and they do not require myeloablation with busulfan. Lipid nanoparticles (LNPs) and adeno-associated virus (AAV) could be used in vivo to deliver gene therapies such as CRISPR/Cas machinery for knockout of the B-cell lymphoma 11A (BCL11A) enhancer, but they are not cell-type specific. Conventional lentivirus is generally not immunogenic on first dose and delivers larger payloads than LNPs and AAVs. However, conventional lentivirus lacks cell type specificity. We have recently used bioinformatics and high-throughput screening to innovate novel lentiviral particles for engineering genes into T cells, achieving >95% target cell transduction efficiency and >95% cell type specificity. The Specific Aim of this Phase I SBIR project is to test a novel lentiviral technology for editing HSCs for the treatment of β-hemoglobinopathies. In Phase I, we will use in vitro assays to assess the efficiency and specificity of HSC-tropic LV which deliver CRISPR/Cas9 machinery for knockout of the BCL11A enhancer versus HSC- tropic LV for transgenic expression of anti-sickling βAS3-globin.