The device improved blood-sugar control more than standard monitors and insulin pumps did when tested for five days on 20 adults and 32 teens. Unlike other artificial pancreases in development that just correct high blood sugar, this one also can fix too-low sugar, mimicking what a natural pancreas does.

The device was developed at Massachusetts General Hospital and Boston University. Results were featured Sunday at an American Diabetes Association conference in San Francisco and were published online by the New England Journal of Medicine.

"I'm very excited about it," said Dr. Betul Hatipoglu, an endocrinologist at Cleveland Clinic who had no role in the work. Many patients have been frustrated waiting for a cure, so "this is really a great new horizon for them," she said.