New blindness treatment could be a gene therapy breakthrough

Aysha Khan

A new treatment for a rare eye condition may soon become the first successful form of gene therapy on the market in the USA. 

After successful clinical testing, biotech company Spark Therapeutics announced on Monday its plans to apply for approval from the USA’s Food and Drug Administration (FDA) next year to sell the treatment.

Gene therapy involves putting healthy genes into the body to replace mutated genes that have caused disease. In this case, the treatment (called SPK-RPE65) is injected directly into the eye, using a viral agent to insert a functioning gene into cells that lack it.

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In a clinical trial of 31 patients with mutated genes, subjects were then asked to navigate a mobility course under various light levels. After a year, the 21 subjects who received the therapy had seen improvements in their vision with no serious side effects, according to the researchers.

“We saw substantial restoration of vision in patients who were progressing toward complete blindness”

said Albert Maguire, the study’s lead researcher and University of Pennsylvania ophthalmology professor, in a statement

The degenerative condition is caused by a mutation in a gene called RPE65 – this gene plays a key role in maintaining the health of the retina. Symptoms include loss of peripheral and night vision but can eventually lead to full blindness. Inherited retinal degeneration affects about 200,000 Americans, according to the Foundation Fighting Blindness, which funds research in this area. CNBC reports that about 3,500 people in the U.S. and five large European countries suffer from the RPE65 gene mutation that Spark’s drug aims to treat. 

“This is a watershed moment in the long-time pursuit of innovative gene therapy solutions for a range of blinding retinal degenerative diseases,”

said Gordon Gund, chairman of the Foundation Fighting Blindness.

There have been hundreds of gene therapy trials since 1990, but none so far have resulted in a drug being granted approval from the FDA. For instance, American drug developer Celladon’s promising treatment for heart failure disappointed in a phase three trial in April this year. 

Prospects for gene therapy look a little brighter in the UK.

After 25 years of intensive research into gene therapy for cystic fibrosis, trials by a group of U.K. universities at last found a positive result in July, according to The Lancet Respiratory Medicine. The Financial Times reports that clinical trials could begin as soon as 2017.

In February, the U.K. became the first country to approve a mitochondrial gene therapy, which would combine DNA between two biological parents and an egg donor. The in vitro fertilization method was particularly controversial globally because changes made to the mother’s genes would be replicated in child’s embryo.

After denying it thrice, the E.U. approved Europe’s first gene therapy, UniQure NV’s Glybera, in 2012. Glybera treat patients with an extremely rare and potentially fatal enzyme deficiency that results in acute pancreatic inflammation. The pioneering therapy has not been approved in the U.S. Costs are still at a sky-high $1 million in Europe, where health authorities are still questioning its use.

With major questions on the longevity and effectiveness of Spark’s therapy still remaining, all eyes will be on the team’s presentation at Retina Society Annual Scientific Meeting next week.

Featured image via Flickr Creative Commons.

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