Marlene Busko July 05, 2023

SAN DIEGO – In the largest randomized controlled trial of an automated insulin delivery (AID) system (hybrid closed-loop) versus standard insulin delivery in pregnant women with type 1 diabetes, the automated CamAPS FX system prevailed.

The percentage of time spent in the pregnancy-specific target blood glucose range of 63-140 mg/dL (3.5-7.8 mmol/L) from 16 weeks gestation to delivery was significantly higher in women in the AID group.

Helen R. Murphy, MD, presented these topline findings from the Automated Insulin Delivery Amongst Pregnant Women With Type 1 Diabetes (AiDAPT) trial during an e-poster session at the American Diabetes Association (ADA) 83rd Scientific Sessions.

The “hybrid closed-loop significantly improved maternal glucose and should be offered to all pregnant women with type 1 diabetes,” concluded Murphy, a professor of medicine at the University of East Anglia and a clinician at Norfolk and Norwich University Hospital in the UK.

CamAPS FX is the only AID system approved in Europe and the UK for type 1 diabetes from age 1 and during pregnancy. The hybrid closed-loop system is not available in the United States but other systems are available and sometimes used off-label in pregnancy. Such systems are sometimes known colloquially as an “artificial pancreas”.

The researchers believe their findings provide evidence for the UK National Institute of Clinical Excellence (NICE) to recommend that all pregnant women with type 1 diabetes should be offered the CamAPS-FX system.

Asked by an audience member about type 2 diabetes in pregnancy, Murphy said: “I don’t think we can necessarily extend these data to women with type 2 diabetes. We just don’t have enough data on glucose profiles in type 2 to train an algorithm yet.”  

However, the data provide support for earlier use of closed-loop therapy in type 1 diabetes, she said. “The ideal time to start closed-loop is not necessarily between 8 and 12 weeks. Half of all pregnancies are unplanned,” she noted, “so start [AID] as early as possible [in patients with type 1 diabetes].”

Two Experts Weigh-In

Whether pregnant women with type 1 diabetes should be offered hybrid closed-loop therapy “depends,” said Anne Peters, MD, who was not involved with the research.

“It is all about being able to set [blood glucose] targets,” according to Peters, a Medscape contributor and director, University of Southern California Westside Center for Diabetes, in Los Angeles.

“If a woman is on an AID system — except for DIY loop — I have them stop the automation and adjust manually,” she told Medscape Medical News in an email. “My [patients] do amazingly well in pregnancy — most can get their A1cs below 6%,” she noted. “But if someone can’t do that and their A1cs are higher, automation can help.”

“It is always about individualizing care,” according to Peters. “The one thing that helps the most is continuous glucose monitoring (CGM). And I do have patients who remain on [insulin] injections throughout pregnancy.”

And Sarit Polsky, MD, MPH, who was not involved with the current study, agrees that “AID with CamAPS, which has an option to customize the glucose target in the pregnancy-specific range, appears to be safe and effective in pregnancy and should be offered” to patients in Europe and the UK.

“Whether other AID systems should be recommended in pregnancy is still unclear, said Polsky, associate professor of medicine and pediatrics Barbara Davis Center for Childhood Diabetes, University of Colorado Anschutz Medical Campus.

“Around 48% of [global] pregnancies are unplanned,” Polsky told Medscape Medical News. “Many women do indeed become pregnant while using AID systems and many opt to continue use of these systems.”

“Off-label use of these products can be beneficial in pregnancy in select cases, but the systems generally need the use of assistive techniques, which we previously published, to help get glucose levels to pregnancy-specific targets,” she noted in an email.

Study Rationale, Method, and Findings

Pregnant women with diabetes are advised to aim for very tight glucose targets throughout pregnancy and avoid hyperglycemia, to reduce risk of preterm delivery, neonatal weight > 90th percentile, and neonatal morbidity, according to Murphy and colleagues.

“However, despite increased use of [CGM], continuous subcutaneous insulin infusion (CSII), and improved insulin analogs, achieving and maintaining the recommended glucose targets remains challenging for most pregnant women with type 1 diabetes,” they write in their abstract.

Researchers randomized 124 women who had type 1 diabetes for at least 12 months, were at < 13 weeks’ to 6 days’ gestation, and had an A1c of 6.5% to < 10% who were taking intensive standard insulin therapy at nine antenatal clinics in the UK. Half of the women were using CSII and half were receiving multiple daily injections of insulin. 

As explained in the published study protocol, the women were randomized to continue their standard insulin delivery or switch to a closed-loop system consisting of the study insulin pump (Dana Diabecare RS), a CGM transmitter, and an app (CamAPS FX) on an Android smartphone that communicates wirelessly with the insulin pump and CGM transmitter.

Participants in both groups used the same CGM system and received support for insulin dose adjustment from their antenatal clinical care team.

They were a mean age of 31 years, had a mean A1c of 7.7%, and had had type 1 diabetes for 17 years on average. Their body mass index varied greatly: 37% had normal weight, 27% had overweight, and 26% had obesity.

A significantly higher percentage of women in the AID group than in the control group had blood glucose in target range more than 70% of the time (46% vs 10%; P < .001).

Compared with women in the control group, those in the AID group had larger reductions in hyperglycemia (–11%; P < .001), higher overnight time-in-range (13%; P < .001), and lower A1c (–0.34%; P < .001), without additional insulin, weight gain, or hypoglycemia.

The effect was consistent across clinical sites and maternal age and A1c categories.

Ongoing Studies, Off-Label Use

Hybrid closed-loop systems “including Tandem Control IQ, the Omnipod 5, and the Medtronic 780G give insulin continuously on the basis of values obtained from a sensor,” Peters explained in a recent commentary. “These aren’t fully closed-loop systems because the individual still has to interact with the system and give doses for meals, and then adjust doses for exercise.”

There are currently three studies using commercially available AID systems without pregnancy-specific glucose targets, in type 1 diabetes pregnancies, Polsky noted.

The Pregnancy Intervention With a Closed-Loop System (PICLS) trial used the Medtronic 670G system in pregnancy and was conducted in the United States. The Closed-Loop Insulin Delivery in Pregnant Women With Type 1 Diabetes (CRISTAL) study is using the Medtronic 780G system in pregnancy and is being conducted in Belgium and the Netherlands. And the Closed-Loop Insulin Delivery in Type 1 Diabetes Pregnancies (CIRCUIT) study is using the Tandem Control IQ system in pregnancy and is being conducted in Canada, she explained.

“The decision to continue to use or to initiate (off-label) use of any of these systems in pregnancy should be individualized, and pregnant individuals should make these decisions by working with an experienced endocrine/diabetes team,” Polsky stressed.

“The hope is that the results of these exciting trials will show safe and effective use of these systems throughout gestation with improvements in glucose control and quality of life,” she concluded.

The study was funded by the UK National Institute for Health Research, JDRF, and Diabetes Research and Wellness Foundation. Murphy has reported being on the advisory panel for Medtronic and receiving research support from Dexcom. Disclosures for the other authors are listed with the abstract. Peters authors a video commentary for Medscape and disclosed that she served as a consultant for Blue Circle Health, Vertex, and Abbott Diabetes Care, received a research grant from Abbott Diabetes Care, and received stock options from Teladoc and Omada Health. Polsky has disclosed that she is a contributing writer for diaTribe, was on a medical advisory board for Medtronic MiniMed, has received research funding from DexCom, Eli Lilly, JDRF, Leona & Harry Helmsley Charitable Trust, NIDDK, and Sanofi, and has received research support from Diasome Pharmaceuticals, LabStyle Innovation, Lexicon, Medtronic MiniMed, and Sanofi.

ADA 2023 Scientific Sessions. Abstract 108-LB. Presented June 25, 2023.