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Home » News and Events » Statements and Reports on Vision » Phase 1 Clinical Trial Results of Gene Transfer for Leber Congenital Amaurosis Reported

NEI Statement

National Institutes of Health
National Eye Institute

For Immediate Release September 8, 2008

Phase 1 Clinical Trial Results of Gene Transfer for Leber Congenital Amaurosis Reported

Three young adults with Leber Congenital Amaurosis-a severe degenerative disease of the retina caused by a mutation in the RPE65 gene-reported improvements in vision after undergoing a specialized gene transfer procedure. In October and December, 2007, and late January, 2008, patients received a sub-retinal injection to replace the nonfunctioning gene as part of a phase 1 clinical trial funded by the National Eye Institute (NEI), part of the National Institutes of Health. The clinical study led by investigators at the University of Pennsylvania, Philadelphia and the University of Florida, Gainesville tested the safety of the gene transfer procedure in humans.

"This groundbreaking gene therapy trial builds on 15 years of research sponsored by the National Eye Institute, NIH," said Paul A. Sieving, M.D., Ph.D., director of the NEI. "The study has partially restored vision in three young adults, and it demonstrates that gene therapy can be effective in treating human vision disease. Many human diseases are inherited in families and result from mutations in single genes. These genetic conditions are particularly suited to potential treatment by gene therapy. This trial to treat vision loss from the condition of Leber congenital amaurosis is an important demonstration of "proof of principle" and shows that we are on the right track. We can now invest in further work to refine, and ultimately to expand, genetic treatment approaches."

Given the positive results, the study will now be expanded to include more patients and will involve delivering healthy RPE65 genes to a wider area of the retina to confirm the effectiveness of the therapy and to refine gene transfer techniques. For extensive background information on gene transfer and LCA, go to:

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The National Eye Institute (NEI) is part of the National Institutes of Health (NIH) and is the federal government's lead agency for vision research that leads to sight-saving treatments and plays a key role in reducing visual impairment and blindness. For more information, visit the NEI Website at

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


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This page was last modified in October 2008

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