Verve Therapeutics Inc. shares jumped 21% after the company reported no safety issues in a new study of its gene-editing treatment for people with high cholesterol.

The Boston-based company said its treatment was well-tolerated with no serious treatment-related adverse events among 14 participants in an early-stage trial. The treatment led to an average reduction in cholesterol of 53% in patients who received the highest dose, according to a statement.

In a note to clients Monday, William Blair analyst Myles Minter called the results “a best-case scenario for Verve shares.” The company expects to begin a mid-stage trial of the treatment in the second half of this year.

Last year, Verve paused enrollment in an early-stage trial of a previous treatment after one participant developed abnormal liver enzymes and thrombocytopenia, a condition involving low blood platelet counts. Verve attributed the lab abnormalities, which resolved in a few days, to lipid nanoparticles, or tiny balls of fat, used to deliver the treatment.

The biotech firm has also developed a new version of its experimental approach to preventing heart attacks that uses a different delivery method than a prior one.