X-Linked Retinitis Pigmentosa
Retinitis pigmentosa (RP) is the most common inherited form of blindness; it is characterized by progressive vision loss due to gradual loss of the light-sensitive retinal cells called rods and cones. Several different gene mutations can cause RP; most cases of X-linked RP (the gene is carried on the X chromosome) are due to a mutation in RPGR, a protein primarily expressed in photoreceptors in the retina. Mutations in RPGR are associated with a more severe form of the disease, causing early onset of disease, and a relatively fast progression.
Gene therapy for X-linked RP involves a one-time subretinal injection to deliver a normal copy of the RPGR gene to the retina.
NAV® Technology has been shown to be more efficient than the previously studied rAAV serotypes in delivering genes to the target cell type (photoreceptors). Given the limited volumes that can be injected in the subretinal space, a more efficient vector is expected to deliver higher efficacy at a given dose. The proposed therapeutic is in the research stage of development.