A pioneering clinical trial at the University of Michigan has demonstrated that adult stem cell transplants can safely improve vision in patients with advanced dry age-related macular degeneration. Early results from six participants show significant sight gains without serious side effects. Researchers are now evaluating higher doses in additional patients.
Age-related macular degeneration (AMD) affects roughly 20 million adults in the United States, primarily those over 60, by damaging the macula and causing central vision loss. While peripheral vision remains, patients struggle with tasks like reading or recognizing faces. Current treatments only slow progression, but a new study in Cell Stem Cell explores regenerative options using retinal pigment epithelial stem cells derived from adult postmortem eye tissue.
In a phase 1/2a trial, six participants with advanced dry AMD— the most common form, affecting over 90% of cases—underwent surgery to receive the lowest dose of 50,000 specialized stem cells. These cells, limited to maturing into retinal pigment epithelial cells, aim to replace malfunctioning or dead ones in the retina. The procedure proved safe, with no reports of serious inflammation or tumor growth.
One year post-treatment, treated eyes showed measurable improvements: participants read 21 additional letters on a standard eye chart, unlike their untreated eyes. "Although we were pleased with the safety data, the exciting part was that their vision was also improving," said Rajesh C. Rao, M.D., Leonard G. Miller Professor of Ophthalmology & Visual Sciences at the University of Michigan. He added, "We were surprised by the magnitude of vision gain in the most severely affected patients who received the adult stem cell-derived RPE transplants. This level of vision gain has not been seen in this group of patients with advanced dry AMD."
The trial now monitors 12 more participants receiving higher doses of 150,000 or 250,000 cells. If safety holds, it will advance to later phases. "We are grateful to all our participants who are allowing us to better understand whether this intervention is safe enough to be a future therapy," Rao noted. This NIH-funded work at the University of Michigan highlights progress in regenerative medicine for irreversible vision loss.