Gene repair tool used in human body

Scientists say they have used the gene editing tool CRISPR inside someone’s body for the first time, a new frontier for efforts to operate on DNA to treat diseases.

A patient recently had it done at the Casey Eye Institute at Oregon Health & Science University in Portland for an inherited form of blindness, the companies that make the treatment announced Wednesday. They would not give details on the patient or when the surgery occurred.

It may take up to a month to see if the procedure worked to restore vision. If the first few attempts seem safe, doctors plan to test it on 18 children and adults.

“We literally have the potential to take people who are essentially blind and make them see,” said Charles Albright, chief scientific officer at Editas Medicine, the Cambridge, Massachusetts-based company developing the treatment with Dublin-based Allergan.

Dr. Jason Comander, an eye surgeon at Massachusetts Eye and Ear in Boston, another hospital that plans to enroll patients in the study, said it marks “a new era in medicine” using a technology that “makes editing DNA much easier and much more effective.”

Doctors first tried in-the-body gene editing in 2017 for a different inherited disease using a tool called zinc fingers. Many scientists believe CRISPR is a much easier tool for locating and cutting DNA at a specific spot.

The people in this study have Leber congenital amaurosis, in which a gene mutation keeps the body from making a protein needed to convert light into signals to the brain.

Scientists can’t treat it with standard gene therapy — supplying a replacement gene — because the one needed is too big to fit inside the disabled viruses used to ferry genes into cells.

So they’re aiming to delete the mutation by making two cuts on either side of it. The hope is that the ends of the DNA will reconnect and allow the gene to work as it should.

Some independent experts were optimistic about the new study.

Dr. Kiran Musunuru, a gene editing expert at the University of Pennsylvania, said the treatment seems likely to work, based on tests in human tissue, mice and monkeys.

The gene editing tool stays in the eye and does not travel to other parts of the body, so “if something goes wrong, the chance of harm is very small,” he said. “It makes for a good first step for doing gene editing in the body.”