The human experiment could entail some risk. Nanoparticles are somewhat toxic, and there have been reports of side effects, like muscle pain, in people taking other drugs to lower PCSK9. And whereas treatment with ordinary drugs can be discontinued if problems come up, there’s as yet no plan to undo gene editing once it’s performed.

So far, the few gene therapies on the market all cost hundreds of thousands of dollars—even as much as $2 million. But Verve’s should be much cheaper, especially if used widely. One reason is that whereas other gene therapies use specially prepared viruses to carry genes, nanoparticles are made in a chemical process that’s more practical to scale up.

“The pandemic and the emergent need for vaccines [created] large-scale manufacturing capacity,” says Kiran Musunuru, a gene-editing expert at the University of Pennsylvania who cofounded Verve.  That capacity “can be easily repurposed for genetic therapy,” he says, and “of course, abundant capacity means reduced prices.”

Musunuru says people are even thinking about “booster shots” in case the first round of gene editing isn’t complete, or in order to knock out other cholesterol genes and deepen the effect on LDL.

It’s a stroke of luck for Verve’s founders that the main cause of death in the world is also the first common problem that gene editing can address. Kathiresan, who takes a statin to keep his LDL low, says he thinks gene editing for cholesterol has the potential to be a life-extension treatment.

“The number one cause of mortality in the world is heart attack,” he says. “If you are going to give a medicine that makes you avoid a heart attack, people are going to live longer.”