Doctors have for the first time administered a gene-editing drug to a human, intended to correct a DNA error directly within the body. The target of the experimental therapy is Wilson's disease, a rare hereditary condition in which the liver is unable to excrete excess copper. Without treatment, the metal builds up to dangerous levels, damaging the liver, the brain and other organs. People with the disease currently have to take medication for the rest of their lives.
Prime Medicine, a biotechnology company based in Massachusetts, reported the first procedure on October 5, 2026. The drug is administered intravenously. It is expected that, carried by the bloodstream, it will reach the liver, find the defective gene and "rewrite" it. If this succeeds, a disease that requires constant treatment could be eliminated in a single procedure. Trial results are expected in 2027.
Copper is essential to the body but toxic in large quantities. Wilson's disease affects roughly one in 30,000 people. It disrupts the ATP7B gene, which is responsible for removing copper from liver cells. The new drug, PM577a, targets one of the most common mutations in this gene, typical of people in Europe and North America. The company is already developing a version for another mutation, which is more common in East Asia.
The therapy is based on "prime editing," an improved method built on CRISPR technology. Unlike its predecessor, which cuts both strands of DNA, the new method makes a nick in only one strand and inserts the corrected genetic code in place of the error. The instructions for this mechanism are delivered to liver cells by lipid nanoparticles, tiny fat capsules similar to those used in mRNA vaccines.
Prime editing has previously been used on humans, but differently: cells were taken from the body, modified in a laboratory and returned. The current approach is more complex, because the editing tool must itself find the right cells inside the body.
I never dreamed that this would be applied to my rare disease in my lifetime. The coming year will be very exciting.
— Ronda Rowland, president of the Wilson's Disease Association, in a comment for Nature
The clinical trial will enroll adult patients whose condition is stable on standard therapy. Doctors will monitor the safety of the method and track how the body absorbs copper. If the liver begins to perform its function, participants may be allowed to stop taking supportive medication. However, even if the genetic correction succeeds, the therapy may not reverse the harm already done to the body.
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