Bionic Pancreas System Safe, Cuts HbA1c in Type 1 Diabetes

A fully automated bionic pancreas improved HbA1c in children and adults with type 1 diabetes, a multicenter randomized trial showed.

Use of this bionic pancreas system led to a drop in HbA1c from 7.9% to 7.3% compared with a steady hold at 7.7% for the standard of care group over 13 weeks (mean adjusted difference -0.5%, 95% CI -0.6 to -0.3, P<0.001), which met the trial’s primary endpoint, reported the Bionic Pancreas Research Group led by Steven Russell, MD, PhD, of Massachusetts General Hospital in Boston.

The same between-group difference in reduction of HbA1c was seen when bionic pancreas users were separated into pediatric (6 to <18 years) and adult (18 years and up) groups, they noted in the New England Journal of Medicine.

Users of the bionic pancreas also spent on average 11% longer in target glucose range (70 to 180 mg/dL) versus the standard of care group, representing a 2.6-hour increase per day. They also spent significantly less time in hyperglycemia (above 180 mg/dL) and severe hyperglycemia (above 250 mg/dL).

The fully automated system was deemed noninferior to standard of care — meeting a key secondary endpoint — for the percentage of time that the glucose level fell into the severe hypoglycemia range: 54 mg/dL as measured by continuous glucose monitoring (CGM; 13-week adjusted difference 0.0%, 95% CI -0.1 to 0.04, P<0.001 for noninferiority).

Overall, bionic pancreas users had a severe hypoglycemia rate of 17.7 events per 100 participant-years versus 10.8 events for the standard of care group (P=0.39). No participants in either group experienced diabetic ketoacidosis.

Beta Bionics’ experimental iLet bionic pancreas system administered insulin aspart or insulin lispro on the basis of body weight and meal announcements without carb counting. Standard of care involved real-time CGM with Dexcom systems paired with any insulin delivery method.

“Inappropriate insulin regimens and errors in estimation and calculation can lead to suboptimal glycemic control,” Russell and team explained.

“Since all insulin doses, including for meals, were autonomously determined by the bionic pancreas, the results of this trial suggest that good glycemic control can be achieved by the bionic pancreas with only qualitative meal announcements and without a prespecified insulin regimen, carbohydrate counting, user-initiated correction doses, or any adjustment of the insulin dose by the user or health care provider,” they added.

In an accompanying editorial, Jennifer Sherr, MD, PhD, of the Yale School of Medicine in New Haven, Connecticut, noted that while “the glycemic outcomes in this trial echo what has been shown with other systems, what makes these findings critically important is that the criteria that are required for use of this mode of insulin delivery actually constitute just one thing: having type 1 diabetes.”

She pointed out that “with the representation of characteristics that mirror the actual experience of a person with type 1 diabetes, these findings can be more easily generalized to real-world application of the technology when regulatory approval is obtained.”

Sherr added that the simplicity of the system is one of the most appealing traits of the bionic pancreas, since the “complexity of the available systems to date has not infrequently impeded prescription,” particularly in areas of the country where endocrinologists are sparse.

For this study, Russell and colleagues included 326 participants ages 6 to 79 years (mean age 28) — 219 in the bionic pancreas group and 107 in the standard of care group. Baseline HbA1c ranged from 5.5% to 13.1%. About three-quarters were white, 10% were Black, and 10% were Hispanic.

At the time of screening, 31% were using a hybrid closed loop system, 31% were using an insulin pump without automation, 34% were on multiple daily injections of insulin, and 4% were on a system with predictive low-glucose suspension.

The most commonly reported adverse event with the bionic pancreas was hyperglycemia (43%). Nearly all of the events in the bionic pancreas group were determined by the medical monitor to be due to infusion-set failure.