

These results pave the way for the next phase of the clinical trial for injection of the highest dose that is 5 and 20 times more concentrated than the low and medium doses described so far. Adverse effects of treatment were mild and included transient inflammation of the eye that was asymptomatic and resolved on its own. In addition, OCT measurements of the retinal nerve fibers showed treatment halted the characteristic degeneration of the optic nerve that continued to deteriorate in untreated eyes at 12 months of follow-up. Still, those who were legally blind for more than two years saw no changes in vision suggesting a window for initiation of treatment may be key. A patient who was legally blind and the first acute case to receive the gene therapy is able to drive again. Average improvement was 0.96 logmar (0.1 logmar equals 5 letters or 1 line on the eye chart) at 18 months of follow-up relative to 0.21 logmar reported in the prior natural history study of those with this mutation. Acuity began to improve within one month of treatment and continued to do so as long as 18 months later. Through this trial, patients with visual loss from LHON received a single-unilateral dose injection of a normal version of their mutated mitochondrial gene into the eye. “These long-term results from the study are very encouraging,” said John Guy, M.D., the principal investigator of the study. The study, conducted at Bascom Palmer Eye Institute of the University of Miami Miller School of Medicine, involved 14 patients with LHON, a disorder caused by genetic defects inside mitochondria, the energy factories inside cells, that results in rapid, permanent and bilateral loss of vision in people of all ages, but primarily men ages 20-40.

for a mitochondrial disease, Leber Hereditary Optic Neuropathy (LHON), initiated in 2014, showed low and medium doses improved visual acuity in most patients when treated within one year of onset of visual loss. Long-term results of the first-ever gene therapy clinical trial in the U.S.
