Gene Therapy is a research technique where the underlying genetic basis of a disease is addressed in order to treat or prevent a disease.
There are a few ways this can be done including:
- introducing a “healthy” copy of the faulty gene – an approach commonly adopted for ‘recessive’ diseases where often there is a deficiency due to the genetic fault. This is the case in Stargardt’s disease (STGD1).
- “switching off” the faulty gene that in ‘dominant’ disease is often producing a toxic product causing harm.
A phase I/II clinical trial of gene therapy to replace a normal copy of the gene that causes Stargardt’s disease, ABCA4, is currently underway.
Sanofi are conducting the trial, which is taking place in Portland, USA (Oregon Health and Science University) and Paris, France (Centre National d’Ophtalmologie des Quinze-Vingts).
A healthy copy of the gene is being surgically administered under the retina with the use of a vector in the form of a virus, which will carry the healthy copy of the ABCA4 gene and deliver it to the light sensitive cells, the photoreceptors, in the outer retina.
There have been no safety concerns to date, with some evidence of benefit in a small number of patients with early mild Stargardt disease. The trial is on-going.
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