April 4, 2024 — The National Eye Institute at the National Institutes of Health has granted the Johns Hopkins Wilmer Eye Institute (WEI) two awards totaling $20 million. WEI will use these awards to fund a six-year clinical trial investigating a potential treatment for retinitis pigmentosa—a condition that currently has no treatments.

Researchers will examine the drug N-acetyle cysteine (NAC) and its ability to slow or halt vision loss caused by retinitis pigmentosa compared to a placebo. Approved by the U.S. Food and Drug Administration to treat acetaminophen overdose, NAC is an antioxidant drug that reduces oxidative stress—a molecular mechanism in the body that may play a role in retinitis pigmentosa, WEI shares. Animal studies conducted by WEI’s Campochiaro laboratory found that high doses of NAC reduced both cell damage caused by oxidative stress and vision loss.

WEI’s trial testing of NAC on human participants will involve approximately 450 people with retinitis pigmentosa from more than 30 medical centers in the U.S., Canada, and Europe. In a double-blind clinical trial, participants will be randomly assigned either a daily oral dose of NAC or a placebo. Participants will receive retinal imaging and vision testing throughout the study at regular intervals to monitor their vision status and retina health.

Associate professor of ophthalmology at the Johns Hopkins University School of Medicine and of biostatistics and epidemiology at the Johns Hopkins Bloomberg School of Public Health Xiangrong Kong, Ph.D., says, “The scale of this study—trying to find a first-of-its-kind and safe treatment for a devastating eye condition alongside its geographic coverage—helps make this study highly significant.”