Reports from Philadelphia on successful early steps in Gene Therapy
24th October 2009
Reuters and The Lancet report on a boy born with a retinal disease that would eventually result in Registered Blindness and totally sightless.
The nine-year-old boy relied on large print on an electronic screen and assisted by teacher aides. Now, after a single injection of genes that produce light-sensitive pigments in the back of his eye, he is able to sit in front with classmates and participates without additional help. He can now actively take part in sport.
This treatment represents the next step toward medical science's goal of using gene therapy to cure disease. Extending a preliminary study published last year on three young adults, the full study reports successful, sustained results that showed notable improvement in children with congenital blindness.
The study conducted by researchers from the Center for Cellular and Molecular Therapeutics at The Children's Hospital of Philadelphia and from the University of Pennsylvania School of Medicine, used gene therapy to safely improve vision in five children and seven adults with a Leber's congenital amaurosis (LCA). The greatest improvements occurred in the children, all of who are now able to navigate a low-light obstacle course--one result that the researchers call "spectacular."
"This result is an exciting one for the entire field of gene therapy," said Katherine A. High, M.D., co-first author of the study and the director of the Center for Cellular and Molecular Therapeutics.
"This study reports dramatic results in restoring vision to patients who previously had no options
for treatment," said High. "These findings may expedite development of gene therapy for more common retinal diseases, such as age-related macular degeneration."
Although the patients did not attain normal eyesight, half of them (six of 12) improved enough that they may no longer be classified as legally blind. "The clinical benefits have persisted for nearly two years since the first subjects were treated with injections of therapeutic genes into their retinas," said senior author Jean Bennett, M.D., Ph.D., F.M. Kirby professor of Ophthalmology
at the University of Pennsylvania School of Medicine.
For Bennett, the results build on nearly 20 years of gene studies on hereditary blindness, starting
with pioneering work in mice and dogs. "These remarkable results," she added, "have laid a foundation for applying gene therapy not only to other forms of childhood-onset retinal disease, but also to more common retinal degenerations."