First Patient Receives In Vivo DNA Editing Therapy for Wilson Disease

In a significant advancement in genetic medicine, Prime Medicine has administered its investigational therapy PM577a to a patient suffering from Wilson disease, marking the first known instance of in vivo prime editing in a living human. The infusion took place in October 2026, and the patient is now part of a global clinical trial aimed at evaluating the safety and effectiveness of this innovative treatment.

Wilson disease is a rare genetic disorder caused by mutations in the ATP7B gene, which impairs the liver's ability to eliminate excess copper. If left untreated, copper accumulates in the body, leading to severe damage to the liver and nervous system. Current management typically involves lifelong medication to help clear copper from the body. The introduction of PM577a represents a potential shift in treatment strategy, as it seeks to directly correct the underlying genetic mutation rather than merely managing symptoms.

The PM577a therapy utilizes a novel approach known as prime editing, which allows for precise modifications to DNA sequences. Unlike traditional CRISPR methods that cut DNA strands, prime editing rewrites specific genetic letters, making it a promising option for conditions like Wilson disease where correcting a mutation is essential. The trial specifically targets the H1069Q mutation, the most common variant associated with Wilson disease in North America and Europe. This one-time infusion is designed to deliver the editing components directly to liver cells, bypassing the need for cell extraction and reinfusion.

The Phase 1/2 trial is open-label and includes adults and adolescents across various dosing groups, with a primary focus on safety and tolerability. While the FDA has cleared the investigational application for PM577a, this does not equate to product approval. As the trial progresses, researchers will closely monitor the delivery effectiveness and any potential adverse reactions, as the editing occurs within the body, complicating the ability to assess individual cells prior to treatment.

Looking ahead, the initial data from this trial is anticipated in 2027, which will be crucial in determining the therapy's efficacy and safety. For patients with Wilson disease who currently rely on daily medication, the results could provide the first clinical evidence of PM577a's potential to offer a more permanent solution. However, further research will be necessary to establish whether a single infusion can replace long-term treatment regimens.