The researchers reported that the system not only worked on 13 monkeys, but it appeared that all of the liver cells were edited. After gene editing, the monkeys’ LDL levels dropped 59 percent in two weeks. Editing the ANGPTL3 gene led to a 64 percent decrease in triglyceride levels.
One danger of gene editing is that the process can result in DNA modification that scientists don’t expect. “It can never have off-target effects,” said Dr. Deepak Srivastava, president of the Gladstone Institutes in San Francisco.
By treating a condition as common as heart disease, he added, even a rare side effect can mean that many patients are affected. So far, however, researchers say they haven’t seen any inadvertent editing of other genes.
Another question is how long will the effect last on cholesterol and triglyceride levels, said Dr. Davidson. “We hope it will be only once, but we have to validate that with clinical trials,” he said.
Jennifer Doudna, a biochemist at the University of California, Berkeley, and discoverer of Crispr, the revolutionary gene-editing system, said: “In principle, Verve’s approach could be better because it is a unique treatment.”
But it is too early to say whether it will be safe and durable, he added.
If the strategy works in humans, its greatest impact may be in poorer countries that cannot afford expensive injections for people at high risk for heart disease, said Dr. Daniel Rader, chair of the genetics department at the University of Pennsylvania and a member . from the Verve Scientific Advisory Council.
Verve’s Dr. Kathiresan noted that half of all first heart attacks end in sudden death, so protecting high-risk people is imperative.