Scientists at the University of Southern California are starting a phase 2b clinical trial to test a microscopic stem cell implant aimed at restoring vision in patients with advanced dry age-related macular degeneration. The hair-thin patch seeks to replace damaged retinal cells, building on earlier research that showed safety and vision gains in some participants. Researchers hope it could offer a way to reverse vision loss where current treatments fall short.
Age-related macular degeneration stands as the leading cause of vision loss among Americans over 65, primarily affecting central vision and leading to blurry spots or blind areas. The advanced dry form, which impacts millions, has few effective treatments to halt or reverse damage to retinal pigment epithelium (RPE) cells in the macula.
At the USC Roski Eye Institute, part of Keck Medicine of USC, a new phase 2b trial is underway to evaluate a bioengineered implant made from lab-grown embryonic stem cells differentiated into RPE cells. This ultra-thin patch, slimmer than a hair strand, is surgically placed in the retina during an outpatient procedure to support and potentially revive vision function.
The trial expands on prior phase 1/2a research involving a small patient group, where the implant proved safe, integrated well with retinal tissue, and led to vision improvements in 27% of participants. "We are hoping to determine if the stem-cell based retinal implant can not only stop the progression of dry age-related macular degeneration, but actually improve patients' vision," stated Sun Young Lee, MD, PhD, the principal investigator and a retinal surgeon at Keck Medicine.
Keck Medicine serves as one of five U.S. sites in this masked study, which will enroll 24 patients aged 55 to 90 with advanced dry macular degeneration and geographic atrophy. Some will receive the implant, while others undergo a sham procedure; all will be monitored for at least one year to assess safety, integration, and vision changes.
"The study will explore if the lab-engineered implant will take over for the damaged cells, function as normal RPE cells would, and improve vision for patients who may currently have no other options for improvement," explained Rodrigo Antonio Brant Fernandes, MD, PhD, the study's surgeon at Keck Medicine.
Developed by Regenerative Patch Technologies LLC, with technology licensed from USC, Caltech, and UC Santa Barbara, the implant receives partial funding from the California Institute for Regenerative Medicine, the Marcus Foundation, and USC. Mark S. Humayun, MD, PhD, co-director of the USC Roski Eye Institute and implant co-inventor, emphasized its potential: "Stem cell-derived retinal implants may offer one of the greatest possibilities for helping patients with dry age-related macular degeneration and one day, may offer a cure."
