Artificial Pancreas Technologies Excel in Real-World Tests
Two studies propelled progress toward development of artificial pancreas technologies, a promising treatment for people with type 1 diabetes. People with this disease do not produce insulin, a hormone made by the pancreas that regulates the level of glucose in the blood and delivers glucose to the cells of the body. Therefore, they have to receive injections of insulin on a daily basis or wear an insulin pump. Too little insulin can lead to high blood glucose, which increases the risk of diabetic complications. Too much insulin, however, is dangerous as well, resulting in low blood glucose (hypoglycemia) which can lead to coma or death, a particular concern during sleep. People with type 1 diabetes walk a tightrope to keep their blood glucose levels within a healthy range and continually must check their levels with fingerstick tests or a continuous glucose monitor. With these burdensome methods it is difficult to achieve recommended levels of blood glucose control. An artificial pancreas, or a closed-loop system, could help people achieve these recommended levels, as well as alleviate patient burden, by linking three technologies: a glucose-sensing component, an insulin delivery device, and a computer that calculates the amount of insulin needed in response to the blood glucose level.
Early artificial pancreas clinical trials took place in hospital settings and used laptop computers to run the technology, restricting the activities of participants. Recent trials have built on the success of the inpatient trials, testing ambulatory devices in real-world settings, with some of the challenges of everyday life—such as eating a variety of foods, which raise blood glucose to different levels, and participating in various forms of physical activity, which lower blood glucose. In one study, scientists achieved exciting results testing unsupervised overnight home use of a closed-loop system in 16 adolescents with type 1 diabetes for 21 nights. During the day, the participants used standard glucose sensor and pump therapy and there were no restrictions placed on their daytime activities—they participated in school and other activities, including sports, and ate a regular diet. At night, they used the closed-loop system, controlling it on their own, with minimal supervision on only the first night. Compared to a control period during which the standard glucose sensor and pump therapy were used both day and night, unsupervised closed-loop control at night improved participants’ glucose control during the day and night, and also reduced the number of episodes of nighttime hypoglycemia. The success of this study illustrates the high potential for closed-loop technology to be translated into clinical care.
In another study, researchers tested a wearable, automated, bihormonal “bionic” pancreas—one that releases both insulin and its counteracting hormone, glucagon. By including both of these hormones, the scientists hope to replicate more closely the sophisticated glucose control of the biological pancreas. They tested the bionic pancreas in two scenarios, one with adults with type 1 diabetes in Boston and one with adolescents with type 1 diabetes at diabetes summer camp. 20 adults wore this device, which was controlled by a cell phone, around Boston for 5 days and nights, unrestricted in their activities. They ate in restaurants, exercised at gyms, and stayed in a hotel and were accompanied by study staff. Thirty-two adolescents at diabetes summer camp wore the same device for 5 days. In both scenarios, compared to usual care (insulin pump), participants had lower mean glucose levels and reduced episodes of hypoglycemia. In fact, the bionic pancreas allowed nearly all participants to achieve recommended levels of blood glucose control.
With the encouraging results of these two studies, additional, larger trials of artificial pancreas technologies could pave the way toward conducting pivotal trials needed for U.S. Food and Drug Administration approval of these technologies. Further development of this technology will also improve efficacy and usability, but this research highlights the ability of artificial pancreas technologies to help people with type 1 diabetes achieve good blood glucose control and lead freer, healthier lives.
Hovorka R, Elleri D, Thabit H, Allen JM, Leelarathna L, El-Khairi R, Kumareswaran K, Caldwell K, Calhoun P, Kollman C, Murphy HR, Acerini CL, Wilinska ME, Nodale M, and Dunger DB. Overnight closed-loop insulin delivery in young people with type 1 diabetes: a free-living, randomized clinical trial. Diabetes Care 37: 1204-1211, 2014.
Russell SJ, El-Khatib FH, Sinha M, Magyar KL, McKeon K, Goergen LG, Balliro C, Hillard MA, Nathan DM, and Damiano ER. Outpatient glycemic control with a bionic pancreas in type 1 diabetes. N Engl J Med 371: 313-325, 2014.