Every gene therapy is comprised of a vector, a promoter, and a transgene, and identifying the appropriate components is critical to developing viable gene therapies. Each component has a role to play:
Vector: Responsible for tissue targeting and delivering the transgene and the promoter to target cells. There are several different types of vectors, including viral vectors such as adenovirus, adeno-associated virus, retrovirus or lentivirus. Other non-viral vectors used in gene therapy include bacterial, lipid- and polymer-based vectors. Patients can potentially have antibodies to some vectors and immune response is important in selecting a vector. Sarepta is currently using adeno-associated virus (AAV) vectors for our gene therapy platform.
Promoter: Responsible for selective gene expression and for driving expression in intended tissue targets.
Transgene: Responsible for producing a functioning version of the protein of interest. The transgene is genetic material introduced into targeted tissues by the vector, and its expression is driven by the promoter.
The transgenes used in Sarepta’s gene therapy programs vary depending on the disease and protein of interest. Some transgenes contain the full copy of the gene of interest; whereas others contain the partial gene, depending on the gene that is needed.
Sarepta’s gene therapy engine is tailored to specific disease states and aims to select individual components that target specific tissues and cells with the goal of optimizing expression of the selected protein in those tissues. Together, these three components form what is called a construct.