Artificial Pancreas Improves Blood Glucose Control

Artificial pancreas system (Tandem Diabetes Care)

17 Oct. 2019. Results of a clinical trial show an automated glucose monitor and insulin pump system provides better blood glucose control for people with type 1 diabetes. Findings from the six-month trial, testing the closed-loop artificial pancreas system against an insulin pump with sensor providing blood glucose levels to the user, appear in yesterday’s issue of the New England Journal of Medicine (paid subscription required).

People with type 1 diabetes have an inherited autoimmune disorder where islet cells in the pancreas do not produce insulin. Type 1 diabetes is diagnosed primarily in children or young adults, where the immune system is tricked into attacking healthy cells and tissue as if they were foreign invaders, in this case, insulin-producing islet cells. From 5 to 10 percent of people diabetes have the type 1 form, estimated at 1.25 million in the U.S.

The technology available today for people with type 1 diabetes to control blood glucose levels is an insulin pump with a sensor-driven glucose monitor that alerts the wearer to release insulin from the pump into the blood stream. A more advanced technology combines the glucose monitor and insulin pump in a single closed-loop system. In the closed-loop system, sometimes called an artificial pancreas because it works automatically, signals from the glucose monitor drive the timing and quantity of insulin released from the pump, without any action from the wearer.

The closed-loop system is made by Tandem Diabetes Care Inc. in San Diego that combines the company’s t:slim X2 insulin pump with a Dexcom G6 continuous glucose monitoring sensor. The system is controlled by software called Control-IQ from the company TypeZero in Charlottesville, Virginia.

As reported by Science & Enterprise in January 2016, the control algorithms and software were first developed by researchers at University of Virginia in Charlottesville and Harvard University, led by Boris Kotchalev and Francis Doyle, respectively, funded by National Institute of Diabetes and Digestive and Kidney Diseases, part of National Institutes of Health. Kovatchev is a senior author and Doyle a co-author of the new journal paper.

The clinical trial enrolled 168 individuals with type 1 diabetes, age 14 to 71, at seven sites in the U.S. Participants were randomly assigned to wear the closed-loop system or the sensor-augmented insulin pump, with twice the number of closed loop system wearers (112) as sensor-augmented pump wearers (56). A key goal of the trial was to test the systems under as close to real-world conditions as possible. Thus, participants checked in with the study team every two to four weeks for device inspections and data downloads, but were otherwise not tracked for the six months of the trial.

The study’s main efficacy measure was the amount of time in the safe-target range of blood glucose levels, from 70 to 180 milligrams per deciliter (mg/dL). Results show participants wearing the closed loop system spend on average 2.6 more hours per day in the safe-target range than sensor-augmented pump wearers. The percentage of time spent in the safe-target range increased from 61 to 71 percent for closed-loop system wearers, while sensor-augmented pump wearers remained at 59 percent. The percentage of safe-target time at night — midnight to 6:00 am — was also higher for closed-loop system participants (76%) than sensor-augmented pump wearers (59%).

All 168 participants finished the trial. No serious hypoglycemic events occurred among any of the participants.

“This artificial pancreas system has several unique features that improve glucose control beyond what is achievable using traditional methods,” says Kovatchev in an NIH statement. “In particular, there is a special safety module dedicated to prevention of hypoglycemia, and there is gradually intensified control overnight to achieve near-normal blood sugar levels every morning.”

John Sheridan, president and CEO of Tandem Diabetes Care, notes in a company statement, “These outcomes, combined with the overwhelmingly positive experiences reported by trial participants, give us confidence that availability of Control-IQ technology will further our mission to improve the lives of people with diabetes, and we continue to prepare for its commercial launch this year, pending FDA approval.”

More from Science & Enterprise:

• Engineered Antibody Delays Type 1 Diabetes Onset
• Closed-Loop System Boosts Diabetes Glucose Control
• Univ. Developing Implanted Islet Cell Bags for Diabetes
• Trial Testing Stem Cell Implants for Type 1 Diabetes
• Artificial Pancreas Controls Type 1 Diabetes Better Than Insulin Pump Alone

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