Bionic Pancreas Controls Blood Sugar in Type 1 Diabetes

The latest version of a wearable, automated bionic pancreas can improve glycemia without increasing hypoglycemia, according to results from 2 outpatient studies. The bionic pancreas, developed by a Boston University/Massachusetts General Hospital research team, consists of a smartphone hardwired to a continuous glucose monitor and 2 pumps that deliver doses of insulin or glucagon every 5 minutes.

”The key element with the current version of this device is that it’s wearable, allowing participants to stay in something close to their usual environments, exercise, and eat whatever they want," said Steven Russell, MD, PhD, of the Diabetes Unit at Mass General Hospital.

Dr Russell presented the results of a controlled trial of 32 adolescents with type 1 diabetes mellitus (DM) (Abstract #237-OR) at the American Diabetes Association (ADA) 74^th Scientific Sessions in San Francisco. He is also the lead author of a paper published online in the New England Journal of Medicine to coincide with the ADA presentation. The NEJM paper also includes results from a study of 20 adults with type 1 DM who tested the device.

In a random-order crossover study in a Diabetes Camp, the 32 adolescents participated in 5 days of glycemic control with the bionic pancreas and 5 days of control care with an insulin pump. “The patients were fully integrated into normal camp activities and meals without restrictions on diet or exercise,” said Dr Russell.

Plasma glucose levels measured by fingerstick and continuous glucose monitor levels were masked to the patients under usual care and were compared between the 2 study arms.

The mean plasma glucose level was 138 mg/dL on the bionic pancreas and 157 mg/dL in the control period. The percentage of all scheduled plasma glucose measurements with values lower than 70 mg/dL was 6.1% during the bionic pancreas period and 7.6% during the control period. The bionic pancreas reduced the mean frequency of treatments for hypoglycemia from just under once a day to just more than once every 1½ days and increased time in the 70 to 180 mg/dL range by continuous glucose monitoring, Dr Russell said.

He noted, “Participants’ average blood glucose went down while the incidents of low blood sugar also dropped. The fear of hypoglycemia can limit attempts to bring the average blood sugar into the range that dramatically reduces the risk of long-term complications, so it was remarkable that we saw both of these results at once.” Fewer instances of hypoglycemia on the bionic pancreas also reduced the need for carbohydrate doses to raise blood sugar.

In both studies, the device “far exceeded our expectations in terms of its ability to regulate glucose, prevent hypoglycemia, and automatically adapt to the very different needs of adults-some of whom were very insulin-sensitive-and adolescents, who typically need higher insulin doses,” said Edward Damiano, PhD, of the Boston University Department of Biomedical Engineering, principal investigator of the project and senior author of the NEJM report. “There's no current standard-of-care therapy that could match the results we saw.”

One of the key virtues of this device is its ability to start controlling blood sugar instantly, based only on the patient’s weight, and continually adapt its decision making regarding insulin and glucagon dosing to handle a wide range of dosing requirements, the researchers noted.