Delivery of Full Length Dystrophin to Muscle Cells for DMD Gene Therapy - PROJECT SUMMARY
Project Title: Delivery of Full Length Dystrophin to Muscle Cells for DMD Gene Therapy
Organization: GigaMune Inc.
PI: David Johnson, Ph.D.
Duchenne’s muscular dystrophy (DMD) is a severe, incurable, X-linked recessive disorder resulting in chronic
muscle wasting caused by any of >7,000 mutations in the dystrophin gene. Wheelchair dependency typically
starts around 12 years, assisted ventilation is generally required by 20 years, and life expectancy is about 27
years. Unfortunately, dystrophin is very large, comprising 3,685 amino acids and an mRNA of 14kb, complicating
delivery of complete dystrophin via adeno-associated virus (AAV), which is limited by a strict payload limit of 5kb.
The ideal gene therapy for DMD would be long-term replacement of the complete dystrophin protein. One option
other than AAV would be lentivirus (LV), which has been used to deliver full-length dystrophin in vitro. GigaMune
has developed a novel next-generation LV platform (GigaLentiTM) for in vivo delivery of any gene to any cell in
vivo. The basis of GigaLentiTM is an abrogated fusogenic pseudotype which leverages cell-surface targeting by
an antibody fragment (scFv) for highly efficient, cell type-specific gene delivery.
We have engineered GigaLentiTM to specifically deliver gene payloads to T and B cells in vitro, but we have not
yet engineered muscle-specific LVs. The Specific Aim of this Phase I SBIR project is to use in vitro models to
develop a novel lentiviral technology for efficient and specific delivery of the full-length dystrophin gene to muscle
cells for modulation of DMD.