Diabetes Care Volume 44, June 2021 e1 Performance of the Insulin-Only Luz E. Castellanos,1 Courtney A. Balliro,1 Jordan S. Sherwood,1 Rabab Jafri,1 iLet Bionic Pancreas and the Mallory A. Hillard,1 Evelyn Greaux,1 Rajendranath Selagamsetty,2 Hui Zheng,3 Bihormonal iLet Using Firas H. El-Khatib,2 Edward R. Damiano,2,4 and Dasiglucagon in Adults With Type Steven J. Russell1 1 Diabetes in a Home-Use Setting Diabetes Care 2021;44:e1–e3 | https://doi.org/10.2337/DC20-1086 Reductions in blood glucose levels in with insulin lispro (Eli Lilly) or aspart (Table 1). The mean CGM glucose and people with diabetes are often (Novo Nordisk), the bihormonal iLet for time in range (70–180 mg/dL) were 149 achieved at the expense of increased 7 days with dasiglucagon (4 mg/mL) ±13mg/dLand72±8%,respectively,in hypoglycemia. A novel approach is to and insulin lispro or aspart, or both, us- the insulin-only period, and 139 ± 11 automatically deliver microdose gluca- ing the same glucose target (110 mg/ mg/dL and 79 ± 9%, respectively, in the gon when automation of insulin deliv- dL), in random order. There were no re- bihormonal period. The mean daily car- ery alone is not sufficient to prevent strictions on diet or exercise. The prima- bohydrates consumed to prevent or hypoglycemia. The approach requires a ry outcomes were prespecified iLet treat hypoglycemia were 16 ± 13 g and bihormonal device and a stable form of operational thresholds. The key second- 18 ± 21 g in the insulin-only and bihor- glucagon or glucagon analog. The iLet ary outcome was the median time with monal periods, respectively. bionic pancreas (Beta Bionics, Inc.) is a CGM glucose <54 mg/dL on days 2–7 The mean total daily dose (TDD) of purpose-built, fully integrated device (after one day of adaptation). dasiglucagon was 0.35 mg/day. All that receives a signal from a continuous All participants completed the study. subjects used one prefilled dasigluca- glucose monitor (CGM) and contains Participants were 21–74 years old and gon cartridge for the entire 7-day pe- autonomous, lifelong learning, mathe- had initial HbA1c levels of 5.7–10.6%. riod. The average daily nausea scores matical dosing algorithms, which are The iLet achieved a CGM capture rate of on a 0–10 visual analog scale were initialized only with the patient’sbody $80% during the insulin-only (90.7%) 0.07 ± 0.12 cm and 0.47 ± 0.83 cm in weight (1). We evaluated the function and bihormonal (88.7%) periods (Table the insulin-only and bihormonal peri- and safety of the iLet in both its insulin- 1). Drug dosing was available >95% of ods, respectively. One participant re- e-LETTER only configuration and its bihormonal the time (99.7% and 99.1% for insulin in ported an episode of vomiting during configuration delivering dasiglucagon, a the insulin-only and bihormonal periods, the bihormonal period. – chemically stable glucagon analog (Zea- respectively, and 99.7% for dasigluca- There were five instances of con- OBSERVATION land Pharma), in a home-use study in gon). The ratio of delivered to attempted firmed insulin leakage at the insulin car- adults with type 1 diabetes (T1D). drug volume was 95–105% (100.3% and tridge connector (one in the bihormonal This open-label, random-order, cross- 99.9% for insulin in the insulin-only and and four in the insulin-only period) that over, home-use trial (clinical trial reg. bihormonal periods, respectively, and led to replacement of the insulin car- no. NCT03840278, ClinicalTrials.gov) 102.0% for dasiglucagon). tridge and connector. In participants was the first human study to test the The median percentage of time with who had confirmed leaks, the insulin bihormonal iLet configuration and the CGM glucose <54 mg/dL was 0.6% (in- TDD was 1.4–3.3-fold higher (mean TDD first multiday use of dasiglucagon in terquartile range [IQR] 0.2–1.1%) and 1.3 vs. 0.6 units/kg/day) and the mean people with T1D (2). Ten participants 0.2% (IQR 0–0.4%) in the insulin-only CGM glucose was 30–72 mg/dL higher used the insulin-only iLet for 7 days and bihormonal periods, respectively (mean 197 vs. 139 mg/dL) on days with 1Massachusetts General Hospital Diabetes Research Center, Boston, MA 2Beta Bionics, Inc., Concord, MA 3Massachusetts General Hospital Biostatistics Center, Boston, MA 4Department of Biomedical Engineering, Boston University, Boston, MA Corresponding author: Steven J. Russell, [email protected] Received 8 May 2020; and accepted 1 March 2021 Clinical trial reg. no. NCT03840278, clinicaltrials.gov © 2021 by the American Diabetes Association. Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered. More information is available at https://www.diabetesjournals.org/content/license. Diabetes Care Publish Ahead of Print, published online April 27, 2021 e2 Performance of the iLet Using Dasiglucagon Diabetes Care Volume 44, June 2021 Table 1—Summary of results iLet operational performance targets Insulin-only iLet Bihormonal iLet iLet operational outcomes CGM glucose readings captured, % $80 90.7 88.7 Insulin delivery channel availability, % $95 99.7 99.1 Ratio of cumulative delivered to attempted insulin volume, % 95–105 100.3 99.9 Glucagon delivery channel availability, % $95 99.7 Ratio of cumulative delivered to attempted glucagon volume, % 95–105 102.0 CGM glucose outcomes ADA consensus targets (3) Insulin-only iLet Bihormonal iLet Median % of time <54 mg/dL (IQR) <1 0.6 (0.2–1.1) 0.2 (0–0.4) Median % of time <70 mg/dL (IQR) <4 4.0 (2.8–4.8) 2.0 (1.3–3.3) Mean CGM glucose, mg/dL (SD) 149 (13) 139 (11) Mean % of time 70–180 mg/dL (SD) >70 72 (8) 79 (9) Mean % of time >180 mg/dL (SD) <25 24 (8) 18 (8) Mean % of time >250 mg/dL (SD) <5 6 (5) 4 (4) Mean coefficient of variation, % (SD) <36 38 (7) 36 (7) Mean standard deviation, mg/dL (SD) 57 (14) 50 (13) Nonglycemic outcomes Mean daily carbohydrates for prevention or treatment of 16 (13) 18 (21) hypoglycemia, g (SD) Dasiglucagon doses, mg/day (SD) 0.35 (0.13) Insulin doses, unit/kg/day (SD) 0.72 (0.23) 0.60 (0.19) As prespecified, iLet operational outcomes are reported for days 1–7, and CGM glucose outcomes and nonglycemic outcomes are reported for days 2–7. ADA, American Diabetes Association. confirmedleaksthanondaysinthe or occlusions supports the practicality the Board of Directors of Beta Bionics, Inc. same arm without documented leaks. for this liquid formulation in clinical R.S. is an employee in, and holds options to purchase stock in, Beta Bionics, Inc. S.J.R. is There were no occlusions or infusion site use. These results support testing the an inventor on a patent and patents pending reactions. There was no severe hypoglyce- next-generation iLet with dasigluca- on aspects of the bionic pancreas that are as- mia or diabetic ketoacidosis, and there were gon in much larger and longer pivotal signed to Massachusetts General Hospital and no serious or unexpected adverse events. trials. are licensed to Beta Bionics; has received Both iLet configurations met the pre- honoraria and/or travel expenses for lectures fi from Novo Nordisk, Roche, and Ascensia; speci ed operational performance targets. serves on the scientific advisory boards of Un- Acknowledgments. The authors thank the However, leaks occurred at the insulin car- omedical and Companion Medical; has received participants for their time and effort; the dia- tridge connector. This was due to off-cen- consulting fees from Beta Bionics, Novo Nordisk, betes care providers who referred potential Senseonics, and Flexion Therapeutics; has re- ter piercing of the cartridge septum prior participants to the study staff; the Massachu- ceived grant support from Zealand Pharma, to insertion into the iLet that led to leak- setts General Hospital (MGH) Diabetes Re- Novo Nordisk, and Beta Bionics; and has re- search Center study staff, Mary Larkin, age through an enlarged hole in the ceived in-kind support in the form of technical septum after needle insertion. This obser- Camille Staco-Targete, Nancy Kingori, Stepha- nie Dimodica, Khadija Tlaiti, and the Diabetes support and/or donation of materials from Zea- vation led to changes in the cartridge re- Research Center, MGH, for organizational and land Pharma, Ascencia, Senseonics, Adocia, and fl placement procedure and to design logistical support; Michele Sullivan for partici- Tandem Diabetes. No other potential con icts of changes in the next-generation cartridge pating in the conduct of the trial; Camille interest relevant to this article were reported. Powe, Kerry Grennan, and Takara Stanley Author Contributions. L.E.C. and E.G. wrote connector and iLet that will be used in the fi (MGH Pediatric Endocrine Division) for serving the rst draft of the letter. L.E.C., H.Z., and pivotal clinical trial. Despite insulin leakage, on the data safety and monitoring board for S.J.R. interpreted the data. C.A.B., J.S.S., R.J., the mean CGM glucose and time in range the study; and the members of the Partners M.A.H., E.G., R.S., F.H.E.-K., E.R.D., and S.J.R. were similar to those observed in previous Human Research Committee. participated in revision of the letter for impor- tant intellectual content. C.A.B., R.J., M.A.H., trials, likely due to autonomous adaptation Funding. L.E.C.