Early gene therapy trial for blindness promising

[Buster's Uncle]

Early gene therapy trial for blindness promising
Preliminary gene therapy trial for blindness promising but too early to know if it will last
Associated Press
By Maria Cheng, AP Medical Writer  2 hours ago



LONDON (AP) -- A small, preliminary study using gene therapy to treat a rare form of blindness is promising and could trigger similar efforts for other causes of vision loss, British doctors say.

They studied just six patients. Of those, two have had dramatic improvements in their vision and none has reported any serious side effects. The study was only designed to test the treatment's safety, not its effectiveness.

Gene therapy —inserting copies of a normal gene into a patient who has a faulty or missing gene — has previously been tried for other rare types of blindness with limited success.

All of the patients in the new trial were men with choroidermia, an inherited and untreatable form of progressive blindness. The disease is the result of a protein deficiency that kills eye cells that detect light.

"We're trying to rescue cells that would otherwise have died," said Dr. Robert MacLaren of the University of Oxford, who led the research. He and colleagues injected a harmless virus carrying the missing protein into the thinnest part of the patients' retinas. The study was paid for by the Wellcome Trust and Britain's Department of Health, and was published online Thursday in the journal, Lancet.

Dr. Ian MacDonald, chairman of ophthalmology and visual sciences at the University of Alberta in Canada, who was not part of the study but is planning a similar trial, called the new work "very promising because there is really no other way to deliver this protein."

Since the paper only had data up to six months after the patients' surgeries, MacDonald said it was unclear if the treatment would last forever or if the men's eyesight would continue to worsen.

Dr. Jean Bennett of the University of Pennsylvania, who conducted earlier work for a different eye disease, called the new study results exciting and said the same approach might be useful for other causes of blindness, including macular degeneration.

But she also said scientists should be cautious in trying future gene therapy treatments. "We can do as much work as we can in the laboratory and try to sort out all the variables, but there are always surprises," she said.

Toby Stroh, 56, had the gene therapy surgery nearly two years ago and credits it with allowing him to keep reading and playing tennis.

"For the last 30 years, I've been living under the inevitability of going blind one day," said the London-based lawyer. "Now there is a real prospect I will be able to continue to see."


http://news.yahoo.com/early-gene-therapy-trial-blindness-154323598.html

[Buster's Uncle]

Gene Therapy Improves Vision for Some with Rare Disease
LiveScience.com
By Rachael Rettner, Senior Writer  18 hours ago



Two adults with a rare disease that causes gradual loss of eyesight had their vision improved after being treated with a new gene therapy, according to preliminary results from a new study.

The study involved six patients ages 35 to 63 with choroideremia, an inherited condition with no cure that causes vision problems early in life, and eventually leads to blindness. Patients have a mutation in a gene called CHM, which causes light-sensitive cells in the eye to slowly stop working.

The goal behind the new gene therapy is to use a safe virus to deliver a working copy of the gene to the right part of the eye to prevent the cells from degenerating.

The new study was an early test of the therapy in which the researchers aimed to carry out the treatment without causing damage to the eye. (Patients must have an eye surgery so that the virus can be injected under the retina with a fine needle).

The result showed that the treatment did not cause harm, and in fact, improved vision in a few of the patients.

Six months after the treatment, four patients recovered the visual acuity (clearness or acuteness of vision) that they had before the surgery, and developed increased sensitivity to light. And two patients had improvements in vision: They were able to read two to four more lines on a sight chart.

"We did not expect to see such dramatic improvements in visual acuity," study researcher Robert MacLaren, of the Nuffield Laboratory of Ophthalmology at the University of Oxford in the U.K., said in a statement. It is still too early to know if the improvements will last, but they have so far been maintained for as long as two years, MacLaren said.

The study is the first to test gene therapy in patients before they'd experienced significant thinning of the retinal cells, MacLaren said.

"Our findings hold great promise for gene therapy to prevent loss of sight in other retinal diseases such as age-related macular degeneration," MacLaren said.

The researchers are now studying the effects of higher doses of gene therapy to find out what level is needed to stop degeneration, MacLaren added.

"It's a very small [study] but the concept is very promising," said Dr. Mark Fromer, an ophthalmologist at Lenox Hill Hospital in New York City, who was not involved in the study.

"Those genes that they're injecting essentially have the ability to make the correct protein" that is unavailable in patients with defective genes, Fromer said.

While larger studies are needed, "it’s the right track" to attempt to correct the problem in patients before they've experienced significant vision loss, Fromer said.

With regard to using the therapy to treat other types of vision loss, Fromer said, "It's is a long road, but it makes a lot of sense to try to treat the disease before it's caused any damage."

The study is published in today's (Jan. 15) issue of the journal The Lancet.


http://news.yahoo.com/gene-therapy-improves-vision-rare-disease-234509217.html

[Buster's Uncle]

Experimental gene therapy improves sight in patients going blind
 By Kate Kelland, Health and Science Correspondent,  Reuters  Jan. 15, 2014 4:29PM PST



LONDON (Reuters) - Toby Stroh was in his 20s when his doctor told him he would go blind in his 50s, and his years of playing tennis and being able to drive or work could be gone long before that.

Now aged 56, two years after his retina was deliberately infected with a virus carrying a gene to correct a protein deficiency that was destroying its cells, he is a regular on the tennis court and has a successful career in law.

"For the last 30 years I've been living under the insidious inevitability of going blind," Stroh told reporters at a briefing about his experimental treatment. "Now there is a very real prospect I will continue to be able to see."

Stroh is one of a handful of patients with an inherited cause of progressive blindness called choroideremia who took part in an early stage trial of a potential gene therapy treatment designed to correct a genetic defect that means retina cells gradually die.

Although the results are from only six patients in a very early stage Phase I trial, researchers said they suggest more studies should be done to see if similar gene therapies could be developed for other more common genetic causes of blindness such as macular degeneration and retinitis pigmentosa.

Choroideremia is caused by a mutation in a gene that makes a protein called REP1. It affects an estimated 1 in 50,000 people and causes sufferers - mainly men - to lose their sight gradually as the cells in the retina degenerate.


DELIVERING DNA

There is currently no licensed treatment for the condition and eventually the photoreceptor cells - the rods and cones in the retina that respond to light by sending signals to the brain - die completely, leading to blindness by middle age.

In the trial, a team led by Robert MacLaren of the University of Oxford, a consultant surgeon at the Oxford Eye Hospital, injected the patients' retinas with a vector - in this case a genetically engineered virus - to deliver a corrective copy of the gene to the appropriate part of the eye.

"The virus has to be delivered to the target cells, which are the cells of the retina," MacLaren explained. To do that, the surgeon performs an operation similar to cataract surgery in which the patient's retina is detached and lifted, and the virus is then injected underneath with a fine needle.

"The virus goes in, infects the cells and puts the protein back into the cells - so we're harnessing the capability of the virus to infect cells and deliver its DNA," he said.

"This is the exciting thing about gene therapy," said MacLaren, whose trial results were published in The Lancet medical journal on Thursday. "We're talking about a single one-off genetic correction ... that has long-standing effects that so far have not been shown to diminish."

The results showed that of the six patients treated - each of them only in one eye so the other could act as a comparison - the two with the least good sight before the gene therapy had significantly improved vision six months later.

In the other four patients, whose vision was only slightly impaired before treatment as they were at earlier stages of the condition, the results confirmed the gene therapy is safe, with the virus delivering its DNA without damaging the retina.

"It is still too early to know if the ... treatment will last indefinitely," MacLaren said. "But we can say that the vision improvements have been maintained for as long as we have been following up the patients, which is two years in one case."

He stressed that the therapy is still in the experimental stage, with more trials likely to take up to five years before it could be submitted for a licence with a view to making it available to all patients.

"If we were able to treat people early, get them in their teens or late childhood, we'd be getting the virus in before their vision is lost," he said. "If the treatment works, we would be able to prevent them from going blind."


http://health.yahoo.net/news/s/nm/experimental-gene-therapy-improves-sight-in-patients-going-blind