Gene therapy for inherited blindness continues to show long-term success. In a clinical study reported by the National Eye Institute, three young adults with Leber Congenital Amaurosis (LCA) cause by RPE65 mutations retained the same dramatic vision improvements one year after treatment with an injected healthy copy of the gene. The therapy restores the missing RPE65 protein, allowing photoreceptor cells to respond to light again. One patient even gained the ability to read an illuminated clock for the first time, showing both retinal and neural adaptation.
These clinical results align with larger long-term data on voretigene neparvovec, the FDA-approved gene therapy for biallelic RPE65 disease. A NIH-linked review shows that vector used in this treatment persists for years as active episomal DNA. Animal studies demonstrated nearly decade-long benefits, and human trials now show sustained demonstrated nearly decade-long benefits, and human trials now show sustained improvements for 5-7.5 years, depending on the test used. Because retinal cells can remain functional for decades, these therapeutic gains may last even longer when treated early.
Adam, this post does an amazing job connecting the molecular mechanism of RPE65 replacement to the real-life impact on patients, especially the clock-reading example, which really humanizes the science. The long-term persistence of the vector as episomal DNA is specifically promising for the durability of treatment effects. It is also encouraging to see how animal model data is now being reinforced by multi-year human trials. In all, this highlights how gene therapy is moving from experimental to truly life-altering medicine.
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