Gene Therapy Provides Vision To Nearly Blind People

Scientists employing a gene therapy have provided partial vision to patients who were nearly blind from a condition known as Leber congenital amaurosis (LCA) -- a severe form of retinitis pigmentosa. Initial results from the clinical trial, which was funded in part by the Foundation Fighting Blindness, were published today in the New England Journal of Medicine.

All three patients, who had severely abnormal vision before entering the study, can now read several lines on an eye chart and are able to see better in dimly lit settings. One was also able to navigate better after the injection.

"This breakthrough is the greatest advancement in the 37-year history of the Foundation Fighting Blindness and the entire history of retinal degenerative disease research. We have achieved a critical milestone in curing a form of childhood blindness," says Gordon Gund, Co-Founder and Chairman of the Foundation Fighting Blindness, which is the largest non-governmental source of funding for this research.

"Our clinical trial results represent an important first step in developing therapies and treatments that will reverse blindness in people with a variety of retinal degenerative diseases," says Jean Bennett, M.D., Ph.D., who is the study's lead researcher at The Children's Hospital of Philadelphia.

"The three participants in the Foundation-supported study at The Children's Hospital of Philadelphia are ages 19-26. Though the trial's main goal was to evaluate safety of the treatment, the research team is very excited about the participants' improvements in vision," says Stephen Rose, Ph.D., Chief Research Officer, Foundation Fighting Blindness.

This Phase I study will continue through its planned enrollment of nine individuals between the ages of 8 and 27. The success in the first three patients, however, will position the researchers well to plan Phase II clinical studies to evaluate the treatment's potential effectiveness in younger children who were born blind from LCA. The investigators believe the treatment has the potential to give near-normal vision t o these children.

The first step toward the development of this treatment began with the discovery of the RPE65 gene in 1993. In 2000, the first dog born blind from LCA, a Briard named Lancelot, was successfully treated with gene therapy, and has been seeing well since then with just a single treatment. More than 50 dogs have now been treated successfully and are all seeing well. Clinical trials of the procedure began in October 2007 at the Foundation-funded Children's Hospital of Philadelphia (CHOP)-Penn Pediatric Center for Retinal Degenerations in Philadelphia.

More than 10 million people across the United States are affected by retinal degenerative diseases which include: macular degeneration, retinitis pigmentosa, and Usher syndrome.