Choroideremia Therapeutic Intervention

Current Therapeutic intervention

For an individual affected by choroideremia, maximising the remaining vision that an individual has is a crucial first step to take, and there are many new low vision aids including telescopic and magnifying lenses. The wide range of assistive technologies for people with visual impairments provides plenty of choice for users at all stages of sight loss, and this technology has also removed many barriers to education and employment.

While there is no current treatment on the market for choroideremia, studies are underway to find potential treatments. As it is a genetic condition where (usually) only one gene is affected, choroideremia is a prime candidate for gene therapy. A genetic diagnosis is very important for affected individuals to access clinical trials for gene therapy. You can find out more about genetic testing on the Know Your Code toolkit here.

There are clinical trials currently underway for choroideremia. You can search for clinical trials at www.clinicaltrials.gov or you can read about trials for IRDs here in our list of IRD-specific trials.

Patient registries are a great resource where information from patients is gathered together in one place. The Choroideremia Research Foundation (CRF) has developed a CHM Patient Registry specifically for people with choroideremia (CHM).

 

What is the CHM Registry?

It is a collection of names and some basic contact information of all the men and women around the world who have CHM.

Why should people join?

  • Clinical trial and study opportunities will start with this list of names.
  • Enable the collection and sharing of information from a large number of patients, with the research community
  • Connects scientists studying CHM with people in The Registry.
  • Amplifies your voice. Opportunity to participate in “Patient Preference and Experience” surveys to come in the future.
  • Improves chances of drug development.

Innovative Therpeutics

 

Gene Therapy

Identification of the specific gene mutations that cause choroideremia has provided the opportunity to develop novel therapies targeted towards addressing the genetic defect. Choroideremia is (usually) due to defects in only one gene and so is a prime candidate for gene therapy.

In gene therapy, genetic material is inserted into cells to compensate for abnormal genes or to make a beneficial protein in order to treat a disease. The most common type of gene therapy being investigated for the treatment of IRDs in clinical trials is gene augmentation therapy. Many IRDs including choroideremia are caused by specific gene mutations which lead to reduced production or loss of the function to the proteins they make (so-called “loss-of-function” mutations). With gene augmentation therapy, a normal functioning version of the disease-causing gene is inserted into the affected retinal cells helping them to produce sufficient levels of the protein, restoring its normal function and preventing cell death.

The potential of gene augmentation therapy for the treatment of IRDs is highlighted by the recent approval, by the FDA in the United States and the EMA of the EU, of voretigene neparvovec (tradename: Luxturna). Luxuturna is approved for the treatment of the RPE65 mutation-associated inherited retinal disease, LCA – click here for further details about Luxturna. While this treatment will not directly be beneficial to people with choroideremia, the success of Luxturna gives hope that treatments for other IRDs such as choroideremia are possible.

Stem-Cell Therapy

Choroideremia is characterised by the irreversible loss of retinal cells, including retinal pigment epithelium (RPE), photoreceptor cells (rods or cones) and choroidal cells, all which lead to vision loss.

Stem cells are undifferentiated immature cells that are capable of self-renewal and can differentiate into specialist cell types, including RPE and photoreceptor cells. The application of stem cells to replace or repair damaged cells in the diseased retina, potentially restoring visual function, is an important area of ongoing research in drug development.

There are different types of stem cells that are being evaluated as potential treatment of IRDs which can be explored on www.clinicaltrials.gov.

Drug Treatments

Choroideremia causes cells in the retina to gradually stop functioning and die, leading to vision loss.  One area of research is looking into drugs to keep these cells healthy and functional. Called neuroprotective agents, they are intended to slow the degeneration of the cells and to slow or halt the progressive loss of vision.