Stay in touch

Hijacking viruses to save sight

July 01, 2020

Your chance to support research on a gene therapy for inherited eye diseases 

Dr Tom Edwards wants to use the infectious power of viruses to develop cures for blinding eye disease using gene therapy.

More than 16,000 Australians live with an inherited retinal disease (IRD). One type, retinitis pigmentosa, is the leading cause of blindness in the working-age population. Currently, there are no cures or treatments.

IRDs affect adults and children alike. For most young people, vision loss is due to a ‘spelling mistake’ in the genetic code that causes cells to malfunction.

With your support, the National Stem Cell Foundation of Australia wants to help fund Tom’s research into new gene therapies for these conditions.

The Foundation aims to provide $100,000 for the project, by matching, dollar for dollar, every public donation of $500 or more, capped at $50,000. You can contribute via our website – just specify ‘EYE’ when prompted.

Tom is a surgeon at the Centre for Eye Research Australia (CERA) in Melbourne, dividing his time between the lab and seeing and treating patients.

He says that one of the hardest parts of being a clinician-researcher is giving patients, especially children, the life-changing news that they have an inherited disease that will inevitably take away their eyesight. He leads a laboratory group focused on developing treatments that may stop this vision loss from progressing.

“Thanks to the exciting progress being made in this field, for the first time we’re able to tell patients there’s hope,” he says.

Gene therapies work by correcting the disease-causing spelling mistakes in a person’s genetic code. Modified viruses are the delivery vehicles.

“When you get a common cold, that’s an example of a virus delivering its trouble-making genetic material into your body,” Tom explains.

“We are borrowing this ability to deliver a genetic payload of DNA to dysfunctional retinal cells.”

Tom and his colleagues reengineer a naturally harmless virus, removing most of its DNA and replacing it with a corrected copy of the patient’s original misspelt retinal gene.

“You’re essentially hijacking the virus to deliver useful genetic material,” he says. “In its simplest form, you’re delivering a functioning copy of the gene that is not working.”

To do his research, Tom needs eye cells with faulty genes. That’s where stem cells come in.

“The retina is the light-detecting layer inside the eye,” he explains. “It’s less than half a millimetre thick and extremely delicate. You can’t just go in and biopsy that tissue because you would damage the eye.”

Skin biopsies, in contrast, are far easier and less invasive, so his colleagues at CERA and the University of Melbourne take skin cells from patients, turn them into stem cells and then into new retinal cells.

“Induced pluripotent stem cell-derived eye cells are an immensely helpful model that can help us to understand how a gene mutation causes disease, and allow us to test different therapies,” said Tom.

Previously, at the University of Oxford in the UK, he worked on an ongoing world-first clinical trial of gene therapy, led by Professor Robert MacLaren, to treat the inherited retinal disease choroideremia, a progressive form of vision loss that mainly affects males.

After promising results from the phase I/II trial, which showed that early improvements in visual acuity were sustained for over three years, the study is now at phase III stage. A treatment may soon be available.

Tom hopes the funding support from the Foundation and its donors will help bring new treatments for IRDs to clinical trial.

“All the surgical techniques required to deliver this treatment have already been developed,” he said.

“We’re just applying them to the task of delivering a precise volume of virus underneath the retina.

“It’s a huge honour to have my project selected and I’m immensely grateful for the Foundation’s support. We now feel a sense of duty to deliver results. Thankfully, I’m fortunate to have a great team at CERA and outstanding collaborators working hard to deliver for our patients.”

Share Tweet Read All News

Sign up for updates!