Prime Medicine doses first patient in Wilson disease gene-editing trial

A global trial of PM577a, the first prime editor tested inside the human body, aims for a one-time fix for Wilson disease. Results are due in 2027.

Prime Medicine, a company based in Cambridge, Massachusetts, has begun a global clinical trial of a prime editor for Wilson disease. The first trial patient received an infusion in October 2026. The company says this is the first time prime editing has been tested inside the human body. Safety and efficacy results are not expected until 2027.

The therapy, PM577a, packs the editor into lipid nanoparticles that target the liver and are delivered through the bloodstream. Wilson disease comes from mutations in a gene for a protein that moves copper out of liver cells. Without treatment, copper accumulates and damages the liver, nerves and brain. Today's management is a lifelong medication regimen. The company hopes to offer a one-time cure and estimates that correcting 20 to 30 percent of liver cells may be enough to help. In monkeys, a single infusion edited about half of liver cells, with no notable changes in liver function, blood chemistry or immune response. In mouse models, the editor corrected 80 percent of cells with minimal off-target edits.

The abundance case is about cost and access over time. A treatment taken for life is a recurring burden. A single infusion, if it works, would be a one-time event. Prime editing, introduced in 2019, could in theory correct up to 89 percent of known disease-associated genetic variants, so a working delivery route to the liver could carry over to other conditions. Prime Medicine dropped its own chronic granulomatous disease therapy partly because each patient needed a custom batch of edited cells, and moved to in-body editing for that reason.

The caveats are large. No human safety or efficacy data exist yet. The animal results were presented at the 2024 AASLD meeting and have not been published in a peer-reviewed journal. The 20 to 30 percent threshold is the company's own estimate. The earlier chronic granulomatous disease data came from just two patients. Watch for the 2027 readout.

Source: Singularity Hub