A single infusion of a stem cell-based treatment may have cured 10 out of 12 people with the most severe form of type 1 diabetes. One year later, these 10 patients no longer need insulin. The other two patients need much lower doses.

The experimental treatment, called zimislecel and made by Vertex Pharmaceuticals of Boston, involves stem cells that scientists prodded to turn into pancreatic islet cells, which regulate blood glucose levels. The new islet cells were infused and reached the pancreas, where they took up residence.

The study was presented Friday evening at the annual meeting of the American Diabetes Association and published online by The New England Journal of Medicine.

“It’s trailblazing work,” said Dr. Mark Anderson, professor and director of the diabetes center at the University of California in San Francisco. “Being free of insulin is life changing,” added Dr. Anderson, who was not involved in the study.

Vertex, like other drug companies, declined to announce the treatment’s cost before the Food and Drug Administration approves it.

A Vertex spokeswoman said the company had data only on the population it studied so it could not yet say whether the drug would help others with type 1 diabetes.