A “bionic pancreas” successfully managed blood glucose levels over the course of two five-day trials in adults and adolescents with Type 1 diabetes, according to new research published in The New England Journal of Medicine and presented at the 74th American Diabetes Association Scientific Sessions earlier this month. Up to three million Americans have Type 1 diabetes, according to diabetes research organization JDRF.
Type 1 diabetes is an autoimmune disorder in which a person’s immune system attacks the insulin-producing beta cells in the pancreas, resulting in the production of little to no insulin. Currently, injections of insulin with a syringe or insulin pen or infusions of the hormone via an insulin pump are the only treatment options available for the condition.
The bionic pancreas, created by researchers at Massachusetts General Hospital and Boston University, is comprised of a smartphone connected to a continuous glucose monitor and two pumps. Every five minutes the smartphone receives a glucose reading from the continuous glucose monitor, which it uses to calculate an appropriate dose of either insulin or glucagon (a hormone that raises blood glucose) and deliver via the appropriate pump. The smartphone also contains an app in which participants enter whether they are about to eat breakfast, lunch, or dinner, and whether the amount of carbohydrates consumed will be typical, smaller, or larger than usual — a far cry from the complex calculations required by current treatments.
The researchers conducted a preliminary trial using a first-generation version of the device in 2010. The study, which included 27 people with Type 1 diabetes, took place in a hospital setting, where the participants ate prescribed meals and mostly stayed in bed. The trial, while successful, exposed some shortcomings of the original device, including that it could not adapt to the changing needs of an individual with Type 1 diabetes and that it could not address the differing needs of adults and adolescents with the condition. (Because of growth and hormonal changes, the insulin needs of an adolescent are two to three times greater than those of an adult who is the same body weight.)
Based on these findings, the research team implemented software improvements to allow the bionic pancreas to adapt to varying dosage needs and also added a smartphone that enables wireless communication between the various components of the device.
To determine the safety and effectiveness of this new, wearable version of the bionic pancreas, the researchers conducted two five-day crossover studies (in which participants receive each treatment in random order) in adults and adolescents with Type 1 diabetes comparing the blood glucose management achieved by the bionic pancreas to that achieved by an insulin pump.
The first trial included 20 people age 21 or over with Type 1 diabetes. The participants were accompanied by a nurse 24 hours a day and were required to stay within a three-square-mile radius of the study site so their blood glucose levels could be continuously monitored by the researchers, but they were otherwise allowed to carry out any activity they chose, such as eating out or going to the gym. The second trial included 32 adolescents ages 12–20 with Type 1 diabetes who were staying at a summer camp for children with diabetes. Their blood glucose levels were closely monitored by camp staff, but they otherwise followed the same meal, activity, and care protocols as the rest of the camp participants.
In both trials, participants saw their average blood glucose levels fall and their incidence of hypoglycemia (low blood glucose) reduced when using the bionic pancreas: When using an insulin pump, both study groups had average blood glucose levels of 159 mg/dl, but when using the bionic pancreas, the adults saw average blood glucose levels of 133 mg/dl and the adolescents had average blood glucose levels of 142 mg/dl. Time spent with low blood glucose, meanwhile, went from 7.3% with an insulin pump to 4.1% with the bionic pancreas in adults and went from 7.6% with an insulin pump to 6.1% with the bionic pancreas in adolescents. Fear of hypoglycemia often prevents people with diabetes from lowering their blood glucose levels into the optimal range, the researchers note, so to see both results simultaneously was particularly encouraging. None of the participants experienced a serious low during the study.
“In both of these studies this 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. There’s no current standard-of-care therapy that could match the results we saw,” noted researcher Edward Damiano, PhD, of the Boston University Department of Biomedical Engineering, whose 15-year-old son was diagnosed with Type 1 diabetes at 11 months of age.
One of the most practical benefits of a device such as the bionic pancreas, Damiano added, would be the relief of fear — “fear of going to bed at night and not knowing if your blood sugar level will drop dangerously low while you sleep. Even our study participants, who controlled their blood sugars significantly better than national averages on usual care, ran high levels overnight but still had significant levels of hypoglycemia.”
“And another extremely frustrating aspect of diabetes that would be completely eliminated by this device is the enormous sense of failure when you stare at that glucose meter and, despite everything you do to control it, your blood sugar is not in or near the normal range,” added researcher Steven Russell, MD, PhD, of the Massachusetts General Hospital Diabetes Unit. “But of course you didn’t fail; the tools that are available to you failed. The bionic pancreas we are working toward would relieve that sense of failure and provide a bridge to the often-promised but still elusive cure for Type 1 diabetes.”
The team is currently in the process of conducting two follow-up trials with the bionic pancreas, one of which will compare the effectiveness of the device over 11 days to that of usual care. Users who are within a one-hour drive of the study site will be able to stay in their own home during the trial.
For more information, read the article “Bionic pancreas controls blood sugar levels in adults, adolescents with type 1 diabetes,” see the study in The New England Journal of Medicine, or view the official website of the research group. And to learn more about other milestones thus far in the development of an artificial pancreas, click here.