Gene therapy was used directly in humans for the first time to cure hereditary diseases

A powerful new gene editing technique has been used to change DNA directly in a human's body. This is the first known use of such a treatment in the world.

During a clinical trial, researchers used a tool known as prime editing to correct a genetic mutation in a patient's liver cells. This mutation occurs in Wilson's disease. This is a rare disease that prevents the body from breaking down excess copper.

“I never imagined that in my lifetime I would see something like this being developed for my rare disease,” Rhona Rowland, president of the Wilson Disease Association in Atlanta, Georgia, told Nature. “It’s going to be a really exciting year.”

Earlier this month, an ongoing trial announced that the first patient had been treated. Preliminary study results are expected in 2027.

The medical breakthrough could pave the way for faster, cheaper and less invasive gene therapies. In order to correct life-changing genetic mutations, cells have so far had to be removed from patients, then modified in the laboratory and finally reinserted - a complex and potentially risky approach, as the specialist magazine "Nature" writes.

Wilson's disease is caused by a mutation in the ATP7B gene. This encodes a protein that is responsible for breaking down excess copper in the liver. Without treatment, toxic levels of copper build up, causing severe liver damage, nerve impairment and neurological disorders.

Current – ​​non-genetic – treatments require lifelong medication to eliminate the copper. Gene therapy, on the other hand, could offer a one-time treatment to solve the problem.

Gene changes in living cells present their own challenges, Krishanu Saha, a biomedical engineer at the University of Wisconsin-Madison, told Nature. For example, doctors cannot ensure that the gene changes are correct before the cells begin to multiply. “It depends on what kind of risks you are willing to accept.”

A number of companies are currently working on developing gene therapies that work directly in the body - for example to treat cancer. This was made possible with the discovery of CRISPR-Cas9 – a type of bacterial immune system that specifically cuts the DNA of viruses. After three decades of basic research, scientists succeeded in using the system biotechnologically for the first time in the 2010s to change genetic material in living cells.

So far, the US FDA has approved only one other genome editing therapy, Casgevy, which is used to treat two inherited blood disorders. Casgevy is based on the CRISPR-Cas9 gene scissors, which are often used to switch off genes rather than rewrite their sequences.

The so-called prime editing that was now used is a modification of this technology. Unlike CRISPR-Cas9, prime editing acts as a type of word editing program that can insert, delete and replace small segments of DNA with extremely high accuracy.

The method used in the current study was developed by the US biotechnology company Prime Medicine. She relies on tiny lipid nanocapsules to bring the gene editing tools inside the liver cells. A similar shuttle technology is also used for mRNA vaccinations. The difference is: mRNA molecules only provide the cells with a blueprint, which, according to current research, is quickly broken down by the body - CRISPR-Cas9 and Prime Editing, on the other hand, change the blueprint itself.