Retinitis Pigmentosa (RP)
RP is the leading cause of hereditary blindness in developed countries, with a prevalence of about
1.5 million people throughout the world.
In Europe and the United States, about 350,000 to 400,000 patients suffer from RP and every year between 15,000 and 20,000 patients with RP suffer vision loss. There is currently no curative treatment for RP, which is designated as a rare and orphan disease in the United States and Europe.
RP represents a group of related genetic eye disorders that clinically manifest in both non-syndromic forms involving isolated visual disability as well as syndromic forms involving other organs or tissues, such as Usher Disease or Bardet-Biedl syndrome, which manifests both in the retina and in the cochlea of the ear. The mutations that cause RP are heterogeneous and include recessive, dominant and X-linked forms of more than 60 genes and affect a variety of cell functions. Syndromic forms of RP are equally heterogeneous.
RP causes progressive vision loss due to degeneration of rod photoreceptors resulting in the loss of peripheral vision followed by degeneration of cone photoreceptors resulting in the loss of central vision. The first symptom of RP is usually difficulty with night vision, which may occur as early as childhood. The disease progresses over a period of years or decades and ultimately leads to blindness. Some patients become blind as early as age 30, and the majority of patients become legally blind before the age of 60.
The following image illustrates the deterioration of normal vision to blindness in RP:
GS030, is based on optogenetics, a technology that makes cells responsive to light. We are using a bio-engineered AAV2, to which we have exclusive rights in optogenetics, to introduce a DNA sequence that encodes a photosensitive protein, into the nucleus of the target cells. Once this protein is expressed, it confers a photoreceptor-like function to the target cell, enabling the restoration of vision in patients with extremely reduced vision or who are blind due to RP.
Because cells expressing optogenetic protein are less light sensitive than normal photoreceptors, vision under regular daylight conditions is unlikely to be possible. Our biomimetic goggles, which mimic the normal retinal activity of capturing vision information will then amplify the light signal at the appropriate wavelength to enable vision restoration.
GS030 consists of two components:
- A gene therapy product comprising a gene encoding a photoactivatable channelrhodopsin rotein, delivered via a modified AAV2 known as AAV2 7m8; and
- Biomimetic goggles that stimulate the engineered retinal cells. The images are projected by a light source that uses a specific wavelength onto the retina.
We believe the application of this novel technology for the treatment of RP will provide patients with an improvement in sight, thereby resulting in significant improvement of autonomy, independence and overall quality of life.