Reduction of Nocturnal Hypoglycemia and Hyperglycemia in the Home Using Predictive Algorithms

Subjects who are eligible for the clinical trial initially will use a Veo insulin pump and Enlite 2 CGM sensor at home for a minimum of 6 days/week over a 2-week period to verify that the subject is able to use the CGM and insert sensors. The first 10 subjects enrolled will participate in a 2-day overnight hotel-based pilot, collecting a total of 20 nights of data and experience with the system in a transitional hotel setting. The DSMB will review safety data from the 20 night hotel-based pilot study and make recommendations regarding proceeding to the at-home portion of the study. Following DSMB review and approval of the safety data from the hotel study, the first 10 subjects will participate in an Algorithm Assessment Phase of approximately 10 nights of Predictive Low Glucose Suspend (PLGS) + Hyper Minimization system use each (for a nominal total of 100 nights of use at home) to determine if any adjustments to the algorithm parameters are needed and if it is safe to advance to the randomized clinical trial phase. If adjustments are needed, the Algorithm Assessment Phase will be repeated, using the same 10 subjects if possible. Once the randomized clinical trial phase begins, approximately 200 nights of randomized system use will be collected and assessed for safety by the DSMB before proceeding. New subjects who enroll in the study after the completion of the Algorithm Assessment Phase will use the PLGS+Hyper Minimization closed-loop system at home for at least 5 days to demonstrate their ability to use the system and submit study data to the Coordinating Center. Subjects who successfully demonstrate their ability to use the system at home as described above will be eligible for the randomized trial phase. This phase consists of use of the full system in the home for approximately 42 nights: * Each night the blood glucose level will be checked with the BG meter and used to perform a calibration of the CGM. This calibration must occur no more than 90 minutes prior to activation of the system. NOTE: Subjects will be instructed to calibrate the CGM per manufacturer guidelines. * Then the system will be activated, linking the CGM and insulin pump to the computer at the bedside. * A randomization schedule on the laptop will be used to determine whether the system will run in PLGS+Hyper Minimization mode or PLGS-only. * Subjects will be blinded as to whether the system is running in PLGS+Hyper Minimization mode or PLGS-only. * There will not be an alarm if the pump shuts off or if automated insulin dosing occurs. The CGM alarm will be set to 60 mg/dL (3.3 mmol/L). When a CGM alarm occurs, the subject will be asked to measure the blood glucose with a BG meter, if he/she is aware of the alarm. * The time period for outcome assessment each night will be from the time the system is activated until it is turned off in the morning. * Pump shut off, when it occurs, will be for up to 120 minutes in a 150-minute period, and no more than 180 minutes for the entire night. Multiple instances of pump suspension can occur if there are recurrent predictions of hypoglycemia during the night. * Small correction boluses of insulin will be delivered when the system predicts that hyperglycemia above a pre-set threshold will occur, with insulin-on-board constraints and cumulative delivery limits to minimize the likelihood of excessive insulin delivery. * Subjects will be asked to check blood glucose with the study BG meter each morning prior to breakfast and enter the results using the controller software interface. The subject will be instructed to contact the study physician if the morning blood glucose value is \<60 mg/dl (3.3 mmol/L) or \>300 mg/dl (16.7 mmol/L). Monitoring processes detailed in section 3.11 will ensure that the subject can be contacted if these values are not reported as required or are out of range. * Subjects will be asked to record all overnight carbohydrate intake using the controller software interface. * Subjects will be asked to perform periodic CGM data uploads using the controller software interface. Monitoring processes will ensure that the subject can be contacted if these uploads do not occur as required, or if review of an upload reveals any extreme, prolonged episodes of hypoglycemia or hyperglycemia, or elevated morning blood glucose values. Upon completion of the study, subjects as well as study clinicians will be asked to complete a human factors usability questionnaire regarding use of the study system.