(9) Automated Insulin Delivery with the iLet Bionic Pancreas for the Management of CFRD

Background: Management of cystic fibrosis-related diabetes (CFRD) requires intensive insulin therapy, frequent blood glucose monitoring, and close attention to carbohydrate intake. Advances in diabetes technology have led to the development of systems that partially automate insulin delivery by employing continuous glucose monitoring (CGM) and insulin pumps that automatically adjust insulin delivery based on mathematical algorithms. These systems have primarily been developed for, and studied in, patients with type 1 diabetes and are associated with improved glycemic control. There are limited prospective clinical trials investigating these devices in CFRD. The iLet^® bionic pancreas (BP) automates all insulin delivery after being initialized with only the user’s weight, without prescribed insulin settings, and adapts autonomously and continually to each user’s changing insulin needs. Additionally, the system eliminates the need for quantitative carbohydrate counting; users enter meal announcements based on meal type (“breakfast”, “lunch”, or “dinner”) and relative size for the user (“typical”, “small” or “large”).

Methods: Study

Design: We tested the feasibility of using the BP for the management of CFRD in an open-label, randomized, cross-over trial compared to usual diabetes care (UC). Each study arm was 2 weeks in duration. Participants were started on the BP without any run-in period and were instructed to maintain similar dietary habits and exercise habits during both arms of the study. During the UC arm, participants who were CGM users wore an unblinded Dexcom G6; otherwise, they wore the blinded Dexcom G6 Pro.

Results: Patient selection criteria: Major inclusion criteria were confirmed CF, age ≥ 10 years, and history of diabetes managed with either an insulin pump or multiple daily insulin injections. Participants were required to have a baseline A1c ≥ 6% or mean CGM mean glucose ≥125 mg/dL. Exclusion criteria included severe liver disease, end-stage renal disease requiring dialysis, a recent pulmonary exacerbation, treatment with IV antibiotics, or change in CFTR modulator therapy within the prior 4 weeks.

Conclusions: Interim results and progress: Eighteen participants have been enrolled and 15 have completed both UC and BP arms. Study completion by 20 participants is expected by June 2022. The baseline characteristics of subjects who have completed the study are noted in Table 1.

Acknowledgements: Funding from the Cystic Fibroation Foundation and the National Institutes of Health: NIDDK

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