Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Gene therapy 1 year later: Patients healthy and maintain early visual improvement

14.08.2009
Phase I clinical trial for genetic eye disease also shows visual benefit for daily activities

Three young adults who received gene therapy for a blinding eye condition remained healthy and maintained previous visual gains one year later, according to an August online report in Human Gene Therapy. One patient also noticed a visual improvement that helped her perform daily tasks, which scientists describe in an Aug. 13 letter to the editor in the New England Journal of Medicine.

These findings have emerged from a phase I clinical trial supported by the National Eye Institute (NEI) at the National Institutes of Health, and conducted by researchers at the University of Pennsylvania, Philadelphia, and the University of Florida, Gainesville. This is the first study that reports the one-year safety and effectiveness of successful gene therapy for a form of Leber congenital amaurosis (LCA), a currently untreatable hereditary condition that causes severe vision loss and blindness in infants and children.

"These results are very significant because they represent one of the first steps toward the clinical use of gene therapy for an inherited form of blindness," said NEI director Paul A. Sieving, M.D., Ph.D. "I anticipate that it is only a matter of time before similar techniques will be applied to other genetic diseases affecting vision."

The three patients in the study—aged 22, 24 and 25—have been legally blind since birth due to a specific form of LCA caused by mutations in the RPE65 gene. The protein made by this gene is a crucial component of the visual cycle. The RPE65 protein is necessary for the production of a retina-specific form of vitamin A that is required for the light-sensitive photoreceptor cells to function. Mutations in the RPE65 gene prevent this production, which halts the visual cycle and blocks vision.

The RPE65 disease offers an opportunity for treatment in that it leaves some photoreceptors intact. In this study, researchers pinpointed an area of intact photoreceptors in the retina of each patient. They injected healthy copies of the RPE65 gene under the retina in this area in an attempt to repair the visual cycle.

One year after the procedure, the therapy had not provoked an immune response in the eye or in the body. Though the patients' visual acuity, or ability to read letters on an eye chart, remained unchanged, all three patients could detect very dim lights that they were unable to see prior to treatment. This visual benefit provides evidence that the newly introduced RPE65 gene is functional and is increasing the light sensitivity of the retina.

"These new reports extend our previous findings from three months after the procedure. At one year, we have now found that the RPE65 gene therapy appears to be safe and leads to a stable visual improvement in the patients studied. We are cautiously optimistic about these results and look forward to additional reports that address the key issues of safety and effectiveness," said Artur V. Cideciyan, Ph.D., research associate professor of ophthalmology at the University of Pennsylvania and lead author of the publications.

At 12 months, one patient also noticed that while riding in a car, she could read an illuminated clock on the dashboard for the first time in her life. When researchers performed additional visual testing, they found that this patient focused on images with a different part of the retina than they expected.

The fovea is the area of the retina where the sharpest central vision normally occurs. However, instead of focusing on images with the fovea, this patient had gradually begun to use the area of the retina that had been treated with gene therapy. The area had already become more light sensitive than her fovea at one month after treatment, but it took 12 months for her to read dim numerals—such as the illuminated clock—that she was previously unable to read.

"This interesting finding shows that over time, a person visually adapted to gene therapy in a meaningful way," said Samuel G. Jacobson, M.D., Ph.D., professor of ophthalmology at the University of Pennsylvania's Scheie Eye Institute and principal investigator of the clinical trial. "As we continue our studies, we will look more closely at whether these slow visual gains could be accelerated with visual training."

Researchers will continue to follow these patients over the next several years to monitor safety and to learn whether the visual benefits remain. This ongoing phase I trial also includes additional groups of LCA patients—children as well as adults—who are receiving different doses of the RPE65 gene therapy.

For additional information about LCA, visit www.nei.nih.gov/lca. Find more information about this trial (NCT 00481546) at www.clinicaltrials.gov.

References:

Cideciyan AV, Hauswirth WW, Aleman TS, Kaushal S, Schwartz SB, Boye SL, Windsor EAM, Conlon TJ, Sumaroka A, Pang J, Roman AJ, Byrne BJ, Jacobson SG. (2009) Human RPE65 Gene Therapy for Leber Congenital Amaurosis: Persistence of Early Visual Improvements and Safety at 1 Year. Human Gene Therapy, vol. 20, no. 9; published online August 2009, ahead of print (doi: 10.1089/hum.2009.086).

Cideciyan AV, Hauswirth WW, Aleman TS, et al. Vision 1 Year after Gene Therapy for Leber's Congenital Amaurosis. N Engl J Med 2009; 361:725-727.

The National Eye Institute (NEI), part of the National Institutes of Health, leads the federal government's research on the visual system and eye diseases. NEI supports basic and clinical science programs that result in the development of sight-saving treatments. For more information, visit www.nei.nih.gov.

The National Institutes of Health (NIH)—The Nation's Medical Research Agency—includes 27 Institutes and Centers and is a component of the U.S. Department of Health and Human Services. It is the primary federal agency for conducting and supporting basic, clinical, and translational medical research, and it investigates the causes, treatments, and cures for both common and rare diseases. For more information about NIH and its programs, visit www.nih.gov.

National Eye Institute | EurekAlert!
Further information:
http://www.nei.nih.gov

More articles from Life Sciences:

nachricht Nesting aids make agricultural fields attractive for bees
20.07.2017 | Julius-Maximilians-Universität Würzburg

nachricht The Kitchen Sponge – Breeding Ground for Germs
20.07.2017 | Hochschule Furtwangen

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Manipulating Electron Spins Without Loss of Information

Physicists have developed a new technique that uses electrical voltages to control the electron spin on a chip. The newly-developed method provides protection from spin decay, meaning that the contained information can be maintained and transmitted over comparatively large distances, as has been demonstrated by a team from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute. The results have been published in Physical Review X.

For several years, researchers have been trying to use the spin of an electron to store and transmit information. The spin of each electron is always coupled...

Im Focus: The proton precisely weighted

What is the mass of a proton? Scientists from Germany and Japan successfully did an important step towards the most exact knowledge of this fundamental constant. By means of precision measurements on a single proton, they could improve the precision by a factor of three and also correct the existing value.

To determine the mass of a single proton still more accurate – a group of physicists led by Klaus Blaum and Sven Sturm of the Max Planck Institute for Nuclear...

Im Focus: On the way to a biological alternative

A bacterial enzyme enables reactions that open up alternatives to key industrial chemical processes

The research team of Prof. Dr. Oliver Einsle at the University of Freiburg's Institute of Biochemistry has long been exploring the functioning of nitrogenase....

Im Focus: The 1 trillion tonne iceberg

Larsen C Ice Shelf rift finally breaks through

A one trillion tonne iceberg - one of the biggest ever recorded -- has calved away from the Larsen C Ice Shelf in Antarctica, after a rift in the ice,...

Im Focus: Laser-cooled ions contribute to better understanding of friction

Physics supports biology: Researchers from PTB have developed a model system to investigate friction phenomena with atomic precision

Friction: what you want from car brakes, otherwise rather a nuisance. In any case, it is useful to know as precisely as possible how friction phenomena arise –...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

»We are bringing Additive Manufacturing to SMEs«

19.07.2017 | Event News

The technology with a feel for feelings

12.07.2017 | Event News

Leipzig HTP-Forum discusses "hydrothermal processes" as a key technology for a biobased economy

12.07.2017 | Event News

 
Latest News

Researchers create new technique for manipulating polarization of terahertz radiation

20.07.2017 | Information Technology

High-tech sensing illuminates concrete stress testing

20.07.2017 | Materials Sciences

First direct observation and measurement of ultra-fast moving vortices in superconductors

20.07.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>