March 5, 2010 Gene therapy for a severe inherited blindness,
which produced dramatic improvements last year in 12 children
and young adults who received the treatment in a clinical trial,
has cleared another hurdle. The same research team that
conducted the human trial now reports that a study in animals
has shown that a second injection of genes into the opposite,
previously untreated eye is safe and effective, with no signs of
interference from unwanted immune reactions following the
earlier injection. These new findings suggest that patients who
benefit from gene therapy in one eye may experience similar
benefits from treatment in the other eye for Leber's congenital
amaurosis (LCA), a retinal disease that progresses to total
blindness by adulthood. Researchers had exercised caution by
treating only one eye in the human trial. In the current study,
the study team found no evidence of toxic side effects in the
blood or the eyes of the 10 animals--six dogs and four monkeys--
that received the gene therapy. Ea