Joint Tandem-Dexcom Closed-Loop Study Shows Improved Time-in-Range

Tandem Insulin pump

The study used Tandem t:slim x2 insulin pumps with Dexcom G6 CGMs.

– Daniel Pereira

A new study published in the New England Journal of Medicine (NEJM) showed promising results for closed-loop insulin delivery systems, the journal and participating manufacturers reported last week.

The 6-month randomized, multicenter trial split a group of subjects with type 1 diabetes into two groups; one group received treatment via a closed-loop insulin pump system (the Tandem t:slim X2™ insulin pump with Control-IQ software, paired with a Dexcom G6 continuous glucose monitor), while the control group received treatment via another conventional insulin pump augmented with a sensor, without closed-loop functionality.

The trial employed 168 patients aged between 14 and 71 years, with HbA1c levels between 5.4 and 10.6. All of the participants were able to successfully complete the trial over the six-month period, and no serious hypoglycemic events affected either group of patients.

Study results support improvement closed-loop improvements

The closed-loop group increased their time in blood glucose range measurably over the study period, from a baseline average of 61 percent up to 71 percent (within a margin of error). 

The control group, meanwhile, remained at the same level of 59 percent time within range, an average difference of more than two and a half hours daily inside target ranges. The difference was even more stark at night, when the closed-loop group reported an average of 76 percent time within range.

For studies such as this NEJM trial, time-in-range has become an increasingly important measurement of successful diabetes therapies, as significant as the traditional HbA1c measurement.

In addition, the Control-IQ system remained in active closed-loop status for 90 percent of the study, reported the authors. One of the challenges experienced by early adopters of closed-loop and interoperable diabetes technologies has been keeping the devices in closed-loop mode, as falling too far out of range or calibration can create possible risks.

Building a pathway toward a closed-loop future

“This NEJM publication recognizes the importance and rigor of the landmark DCLP3 study and the robustness of the safety and efficacy data,” John Sheridan, president and CEO of Tandem Diabetes Care, stated in a press release.

Dexcom CEO Kevin Sayer added that the CGM-manufacturing firm was “thrilled with the results” of the study and highlighted the important role played by CGM technology in enabling closed-loop therapies.

The Tandem t:slim X2 pump received FDA approval late in 2018 and a second round of FDA approval allowing it to be used as an interoperable device – that is, in conjunction with other brands and models of complementary diabetes technology – early in 2019. Dexcom received a similar approval in March 2018.

Many people with type 1 diabetes see closed-loop solutions as the next major step in therapies for the disease, replicating much of the function of a healthy pancreas, so clinical trials showing positive results promises hopeful developments for the future of type 1 diabetes technology.

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