Not only did the system work in 13 monkeys, the researchers reported, but it appeared that every liver cell was edited. After gene editing, the monkeys’ LDL levels dropped by 59 percent within two weeks. The ANGPTL3 gene editing led to a 64 percent decline in triglyceride levels.
One danger of gene editing is the process may result in modification of DNA that scientists are not expecting. “You will never be able to have no off-target effects,” warned Dr. Deepak Srivastava, president of the Gladstone Institutes in San Francisco.
In treating a condition as common as heart disease, he added, even an uncommon side effect can mean many patients are affected. So far, however, the researchers say that they have not seen any inadvertent editing of other genes.
Another question is how long the effect on cholesterol and triglyceride levels will last, Dr. Davidson said. “We hope it will be