First Patient Dosed with In Vivo Gene-Editing Therapy for Wilson Disease, Targeting a Genetic Defect in Copper Metabolism

For patients with Wilson disease, controlling the accumulation of copper in the body is often a lifelong task. Now, a therapy that directly corrects the disease-causing gene has entered human trials: Prime Medicine announced on October 5 that the first patient had been dosed in the global Phase 1/2 trial of PM577a. This is the company’s first in vivo prime-editing therapy to enter clinical studies, with initial data expected in 2027.

Wilson disease is an inherited disorder of copper metabolism in which patients cannot properly eliminate excess copper. Copper consequently accumulates in organs such as the liver and brain, potentially causing serious damage. Current treatment primarily relies on chelating agents to promote copper excretion, or zinc to reduce copper absorption in the intestines. These approaches can control the disease and reduce the risk of organ damage, but require ongoing treatment.

PM577a seeks to address the genetic defect. According to the company, the therapy uses lipid nanoparticles to deliver editing tools through a single intravenous infusion to correct the H1069Q mutation in the ATP7B gene in liver cells. Its clinical value depends on whether this correction can translate into sufficient and lasting improvement in copper metabolism. A single dose is currently part of the therapy’s design; whether it can deliver long-term benefits remains to be verified.

The open-label, dose-escalation trial plans to enroll adults and adolescents who carry at least one H1069Q allele, initially enrolling adults whose disease is stable on standard therapy. The study will assess safety, tolerability, and preliminary efficacy. Dosing the first patient therefore marks the start of human research and does not yet establish that the treatment is effective.

Next, researchers will track whether copper processing changes. Potential assessment tools listed by the company include copper-isotope positron imaging and copper-related markers in blood and urine. The trial will also assess the possibility of discontinuing existing standard therapy. These measurements may provide early clues, but longer clinical follow-up is needed to determine whether improvements in these markers are accompanied by sustained benefits in organ function and quality of life.

This development comes from a company announcement. No patient safety or efficacy results are yet available for review, and independent corroboration of the same event is also lacking. PM577a currently targets only a specific mutation, so its potential benefits cannot be extended to all patients with Wilson disease. When initial data become available in 2027, the first questions to answer will be whether the therapy can safely improve copper metabolism and how long that change can last.