A group of scientists used the CRISPR gene editing tool inside someone’s body for the first time, a new frontier for efforts to operate DNA, the chemical code of life, to treat diseases.
Recently, a patient did so at the Casey Eye Institute of Oregon Health & Science University in Portland for a hereditary form of blindness, the companies performing the treatment announced Wednesday. They did not provide details about the patient or the date of surgery.
It may take up to a month to see if it worked to restore vision. If the first attempts seem safe, doctors plan to test it on 18 more people.RELATED
“We literally have the potential to take people who are essentially blind and have them see,” said Charles Albright, scientific director of Editas Medicine, the Cambridge-based company in Cambridge, Massachusetts, which develops the Dublin-based Allergan treatment. “We believe you could open a new set of medications to enter and change your DNA.”
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 technology that “makes DNA editing a lot easier and much more effective. “
Doctors first tested the editing of genes in the body in 2017 for a different inherited disease using a tool called zinc fingers. Many scientists believe that CRISPR is a much easier tool to locate and cut DNA in a specific place, so the interest in the new research is very high.
The people in this study have congenital Leber amaurosis, caused by a genetic mutation that prevents the body from producing a protein necessary to convert light into signals for the brain, which allows sight. They are often born with little vision and can lose even that in a few years.
Scientists cannot treat it with standard gene therapy, providing a replacement gene, because the one that is needed is too large to fit within the disabled viruses that are used to transport it to cells.
Therefore, they aim to edit or eliminate the mutation by making two cuts on each side. The hope is that the ends of the DNA reconnect and allow the gene to function as it should.
It is performed in a one-hour surgery under general anesthesia. Through a tube the width of a hair, doctors drip three drops of liquid that contain the gene editing machinery just below the retina, the lining on the back of the eye that contains the light-sensitive cells.
“Once the cell is edited, it is permanent and that cell will persist with hope for the patient’s life,” because these cells do not divide, said a study leader who was not involved in this first case, Dr. Eric Pierce.
Doctors think they need to repair between a tenth to a third of the cells to restore vision. In animal tests, scientists were able to correct half of the cells with the treatment, Albright said.
Eye surgery itself poses little risk, doctors say. Infections and bleeding are relatively rare complications.
One of the biggest potential risks of gene editing is that CRISPR could make involuntary changes in other genes, but companies have done a lot to minimize that and ensure that the treatment is cut only where it is intended, Pierce said.
Some independent experts were optimistic about the new study.
Dr. Kiran Musunuru, another gene editing expert at the University of Pennsylvania, said the treatment seems to work, according to tests on human tissues, mice and monkeys.
The gene editing tool remains in the eye and does not travel to other parts of the body, so “if something goes wrong, the possibility of damage is very small,” he said. “It’s a good first step to make gene editing in the body.”
Other scientists are using CRISPR to edit cells outside the body to treat cancer, sickle cell and some other diseases.
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