Gene Therapy & IRDs

IRDs and Retinitis Pigmentosa

Inherited retinal disorders (IRDs) are a group of rare genetic conditions people are born with, that will cause vision loss or blindness. IRDs are conditions that are passed down through family members. IRDs affect the retina, a layer of cells that line the back of the eye and detect light. Many IRDs are rare conditions, meaning they affect small numbers (fewer than 200,000) of people. For years there were no medical treatments for IRDs. Today, doctors are conducting clinical research studies to see if new treatment options may help people with IRDs.

Learn more about our clinical trials

What is Retinitis Pigmentosa?

Retinitis pigmentosa (RP) describes a group of rare genetic eye diseases that damage light sensitive cells in the retina, leading to loss of sight over time. In about 10% of RP cases, the non-working gene is passed down from the mother to her children, resulting in a form of RP known as X-Linked RP (XLRP).

XLRP causes gradual vision loss in males. The disease begins with night blindness and is followed by slow narrowing of the peripheral field of vision. The decline in visual acuity typically results in a person becoming legally blind in their 40s.

Gene Therapy and XLRP

Gene therapy is the process of modifying a patient’s cells by adding a functional copy of the mutated gene which is causing the patient’s disease. The new functional copy allows a patient’s own body to produce proteins to treat or prevent genetic conditions.

AGTC’s current gene therapy clinical trials for XLRP use a subretinal delivery method.

Subretinal administration is a surgical procedure which involves delivery of the AAV vector underneath the retina.  Although this delivery method is a more direct way to introduce the vector to the targeted cells, it requires general anesthesia and a refined surgical technique aimed at maximizing potential benefit while minimizing risks.

Goal of Treatment

It is important to note that gene therapy is not a cure for the disease, but instead a means to control disease progression. By targeting the exact cause of the disease, a faulty gene, gene therapy may be able to eliminate the need for recurring interventions. The investigational study drug is designed to be a one-time administration, as opposed to some treatments for retinal disease that require intravitreal injections as frequently as every three months.