Newswise — New research to be presented this week at AAO 2024, the 128th annual meeting of the American Academy of Ophthalmology, suggests that a new kind of gene therapy can improve vision in people who have lost nearly all sight to retinitis pigmentosa, an inherited condition for which there is no cure and no way to stop it from advancing. While not all patients enrolled in the study responded to treatment, up to 50 percent gained three lines of vision on a standard eye chart. Researchers believe the treatment could also help patients suffering from other types of retinal degeneration.
“We are finally on the brink of an impactful therapy for people with severe vision loss,” said lead researcher Allen C. Ho, MD, director of Retina Research and co-director of the Retina Service of Wills Eye Hospital. “These findings finally deliver hope to patients and ophthalmologists that something is close to being able to help them.”
An estimated 1.5 million people worldwide have retinitis pigmentosa, a group of rare eye diseases that affect the retina, the light-sensitive layer of tissue in the back of the eye. The condition causes the cells responsible for sight, called photoreceptors, to break down over time, causing vision loss. It starts with loss of night vision and usually progresses to loss of color, side, and central vision.
Dr. Ho and his colleagues are investigating a technique called optogenetics to target cells in the retina that don’t normally sense light but often survive after photoreceptors die. It's a one-time intravitreal injection into the eye that uses a harmless virus to deliver copies of light-sensing molecules (Multi-Characteristic Opsin gene) to the surviving cells, turning them into new light-sensing cells to replace lost photoreceptors.
Unlike earlier optogenetics therapies that combined an eye injection with the use of high-tech goggles, this experimental treatment (MCO-010) doesn't require any external device or high intensity light stimulation to coax the cells to respond to light.
MCO-010 is not the first gene therapy to improve vision in patients with retinitis pigmentosa. Luxturna (voretigene neparvovec) is the first FDA-approved gene therapy for retinitis pigmentosa. It works by replacing a faulty gene with a healthy one. But it only works in people who have a specific gene mutation, RPE65, which represents 0.3 to 1 percent of all retinitis pigmentosa cases.
MCO-010 is a mutation agnostic strategy, meaning it doesn’t target a specific gene for replacement. Instead, it works by counteracting damage to the retina caused by numerous different genetic mutations. That’s why this strategy could potentially treat more people with retinal degenerative diseases, such as macular degeneration and Stargardt disease.
Dr. Ho will present 100-week results from a randomized, controlled Phase 2b/3 trial of MCO-010 therapy in patients who had severe vision loss. Most patients had vision characterized as hand motion, light perception or worse. A total of 27 patients were randomized to receive either high or low-dose treatment or sham treatment. Earlier studies showed that both treated groups experienced a statistical increase in visual acuity compared with sham treated patients at weeks 52 and 76, with no patient suffering a significant side effect.
“The statistical significance achieved at multiple time points during the 2-year study is highly noteworthy. This degree of improvement has never been before observed in a randomized, controlled trial of a highly heterogenous patient population treated with this mutation-agnostic gene therapy,” Dr. Ho said. “Not all patients responded to intervention, but 40 to 50 percent gaining 3 lines of vision was surprisingly strong. For example, some study subjects improved from baseline light perception vision to 20/400 or even better.”
The company developing MCO-010, Nanoscope Therapeutics, expects to initiate a Biologics License Application submission with the FDA early in 2025. The FDA has already granted Fast Track designation.
“We are diligently working to get MCO-010 in the hands of ophthalmologists to treat patients as soon as possible,” said Dr. Ho, who also serves as Nanoscope’s Chief Medical Advisor. “We are also aligned with FDA on a phase 3 trial design evaluating MCO-010 in Stargardt macular degeneration and have begun trial start-up activities.”
About the American Academy of Ophthalmology
The American Academy of Ophthalmology is the world’s largest association of eye physicians and surgeons. A global community of 32,000 medical doctors, we protect sight and empower lives by setting the standards for ophthalmic education and advocating for our patients and the public. We innovate and support research to advance our profession and to ensure the delivery of the highest-quality eye care. Our EyeSmart® program provides the public with the most trusted information about eye health. For more information, visit aao.org.
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