Diabetes Closed-Loop Project 6 (DCLP6): Fully Automated Closed-Loop Control in Type 1 Diabetes Using Meal Anticipation

This is a pilot study to assess glycemic responses to three different approaches to insulin dosing for carbohydrate ingestion, with different approaches to a closed-loop system in random order;

• without the meal anticipation module and without carbohydrate announcement (FCL)
• with the meal anticipation module and without carbohydrate announcement (FCL+)
• without the meal anticipation module and with carbohydrate announcement (HCL),

This study will target completion of up to 36 adults in a randomized cross-over trial, comparing blood glucose time in range 70-180 mg/dL following meals with and without the meal anticipation module in use (FCL+ vs FCL), and comparing to a system with carb announcement instead of a meal anticipation module (HCL). The study will also assess safety when dinner is consumed later than usual and when a lunch is consumed without having been entrained in the meal anticipation module. Each participant will complete each of the 3 modules in random order.

Inclusion criteria

• Age ≥18.0 and ≤70 years old at time of consent
• Clinical diagnosis, based on investigator assessment, of type 1 diabetes for at least one year
• Currently using insulin for at least six months
• Currently using insulin pump for at least three months
• Using insulin parameters such as carbohydrate ratio and correction factors consistently on their pump in order to dose insulin for meals or corrections
• Access to internet and willingness to upload data during the study as needed
• For females, not currently known to be pregnant or breastfeeding
• If female and sexually active, must agree to use a form of contraception to prevent pregnancy while a participant in the study. A negative serum or urine pregnancy test will be required for all females of childbearing potential. Participants who become pregnant will be discontinued from the study. Also, participants who during the study develop and express the intention to become pregnant within the timespan of the study will be discontinued.
• Willingness to suspend use of any personal CGM for the duration of the clinical trial once the study CGM is in use
• Willingness to use the University of Virginia (UVa) closed-loop system throughout study admission
• Willingness to use the insulin supplied by the study for the hotel stay, if not already using that preparation. Study insulin will be lispro (Humalog) or aspart (Novolog)
• Willingness not to start any new non-insulin glucose-lowering agent during the course of the trial (including metformin, GLP-1 agonists, pramlintide, DPP-4 inhibitors, biguanides, sulfonylureas and naturaceuticals)
• Willingness to eat at least 1g/kg of carbohydrate per day during the hotel admission
• Willingness to reschedule if placed on oral steroids
• An understanding and willingness to follow the protocol and signed informed consent
• Willingness to commit to self-quarantine for at least 5 days before COVID-19 testing (If participant has received a full course of COVID-19 vaccine and data emerge suggesting significantly reduced transmissibility among those receiving that vaccine, this self-quarantine requirement can be waived.)

Exclusion criteria

• History of diabetic ketoacidosis (DKA) in the 12 months prior to enrollment
• Severe hypoglycemia resulting in seizure or loss of consciousness in the 12 months prior to enrollment
• Pregnancy or intent to become pregnant during the trial
• Currently being treated for a seizure disorder
• Planned surgery during study duration
• Treatment with any non-insulin glucose-lowering agent (including metformin, GLP-1 agonists, pramlintide, DPP-4 inhibitors, SGLT-2 inhibitors, biguanides, sulfonylureas and naturaceuticals)
• A known medical condition that in the judgment of the investigator might interfere with the completion of the protocol.
• Use of an automated insulin delivery mechanism that is not downloadable by the subject or study team
• Known contact with a COVID-19 positive individual within 14 days of the hotel/rental house studies.