Gene therapy on trial for eye disease

A new gene therapy for wet aged-related macular degeneration (AMD), the most common cause of blindness in the developed world, has shown positive interim results in safety and efficacy tests.

Wet AMD leads to rapid vision loss and costs up to $6 billion worldwide each year. It occurs when there is an overproduction of vascular endothelial growth factor (VEGF) in the retina.

VEGF helps support oxygen supply to tissue when circulation is inadequate, but when too much is produced it can cause disease, including blood vessel disease in the eye.

Current treatment for wet AMD is intensive and intrusive - involving monthly injections of anti-VEGF drugs that limit production of VEGF.

Principal Clinical Investigator Professor Ian Constable and the clinical research team at the Lions Eye Institute in Perth have recruited 40 patients to the trial.

“To date, the safety profile is excellent - we have found no serious adverse effects in the eye - and so far we have promising data on how it works,” Professor Constable said.

“The gene therapy involves a single injection of a modified and harmless version of a virus containing a specific gene that stimulates supply of a protein which then blocks overproduction of VEGF,” Professor Constable explained.

The rights to the technology have been licensed by US company Avalanche Biotechnologies.

“This is research of international significance and a huge academic achievement for The University of Western Australia, the Centre for Ophthalmology and Visual Science and the Lions Eye Institute,” he said, adding it is one of the few examples of an Australian research group taking an idea from the laboratory bench to commercialisation.

The science behind the treatment began more than 20 years ago when Professor Constable recruited Professor Elizabeth Rakoczy, a molecular ophthalmologist, to the Lions Eye Institute.

Extensive laboratory and preclinical research was conducted in Perth, Beijing and Singapore, and it was the first research in Australia using gene therapy in ophthalmology or any other medical field.

The research started in a mouse model and progressed to Briard dogs, whose sight was restored within a month of receiving treatment.

Professor Constable said despite the very promising interim results, more testing was required.

“After the Perth trial, multicentre studies will have to be run in the United States and FDA (US Food and Drug Administration) approval sought, but we believe we are on track to test the investigational therapy in more patients and, if proven safe and effective, make it widely available,” he said.