Scientists have made big progress on a "bionic pancreas" to free some people with diabetes from the daily ordeal of managing their disease, doctors said Sunday. A wearable, experimental device passed a real-world test, constantly monitoring blood sugar and automatically giving insulin or a sugar-boosting drug as needed.

Tested for five days on 20 adults and 32 teens, the device improved blood sugar control more than standard monitors and insulin pumps did. Unlike other artificial pancreases in development that correct just high blood sugar, this one also can remedy levels that are too low, 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 the 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.

The bionic pancreas is geared for those with Type 1 diabetes, the kind that often begins during childhood. About 5 percent of the 26 million Americans with diabetes have this type and cannot make insulin to turn carbohydrates into energy. Sugar builds up in the blood, raising the risk for heart disease and many other problems.

Diabetics must check their blood and inject insulin several times a day or get it through a pocket-size pump with a tube that goes under the skin, but that process is largely manual.

"This would lift that burden off of their shoulders," Dr. Steven Russell, a diabetes specialist at Massachusetts General, said of the bionic pancreas he helped design.

It has three parts: two cellphone-size pumps for insulin and sugar-raising glucagon, and an iPhone wired to a continuous glucose monitor. Three small needles go under the skin, usually in the belly, to connect patients to the components, which can be kept in a fanny pack or a pocket.

The iPhone app receives a blood sugar reading from the glucose monitor every five minutes, which it uses to calculate and administer doses of insulin or glucagon, calculated by an algorithm programmed into the app. The patient can also enter information into the app before eating, specifying whether the meal is breakfast, lunch or dinner and whether the carbohydrate content of the meal will be typical or larger or smaller than usual.

Patients still have to prick their fingers to test blood sugar twice a day and make sure the monitor is accurate, but the system takes care of giving insulin or glucagon as needed.

Kristina Herndon said her 13-year-old son, Christopher, "loved it" when he tried it for the study and "felt pretty bad giving it back" when it ended. He has to check his blood sugar eight to 10 times a day, and his family has to watch him closely in case it dips too low while he sleeps, which can cause seizures or even death.

"It's a disease that I think people think is not a big deal, but it's tough. It's hard on a family," said Herndon, who lives in Newburyport, Massachusetts.

A study starts Monday in 40 adults who will use the device for 11 days. By fall, researchers hope to have a next-generation version combining all three components in one device to be tested in studies next year aimed at winning Food and Drug Administration approval.

"My goal is to have this device done by the time my kid, who has Type 1 diabetes, goes to college" in about three years, said Ed Damiano, a biomedical engineer at Boston University.

Two San Diego–based companies — DexCom and Tandem Diabetes Care — made components of the tested version. Boston University and Massachusetts General own or have patents pending on the system, and several researchers may someday get royalties.

Medtronic, Johnson & Johnson and several other companies are also working on artificial pancreas devices.

The Boston group's work is exciting, and the results are compelling, but there are still practical challenges to bringing a device to market, said Aaron Kowalski, who oversees grants by the Juvenile Diabetes Research Foundation on artificial pancreas development.

"Most people with diabetes want less devices in their lives, not more," so putting the components into a single automated system is key, he said.

Al Jazeera and the Associated Press