Further software development is required.

The objective of this study is to test two different operating modes of the latest version of the Dose Safety artificial pancreas system (APS), the Dose Safety Controller (DSC version 2.3), in a population of subjects with type 1 diabetes (TID) in a hospital CRC setting. The first mode is the Fully Automated Closed Loop (FACL) mode, in which all insulin delivery is directed by the controller and the second mode is the Hybrid Closed Loop (HCL) mode, in which insulin delivery is a hybrid between controller directed delivery and user directed insulin delivery. There will be two study arms: HCL and FACL. No comparisons will be made between the two arms.

3.1 Overview Two independent questions will be addressed in this study. For evaluation of the safety and efficacy of the hybrid closed loop (HCL), participants will use the hybrid closed loop during and after a standardized meal on the clinical research center. For evaluation of the safety and efficacy of the fully automated closed loop (FACL), participants will use the system for a 24 hour clinical research center stay incorporating meals and standardized exercise. Safety and efficacy will be evaluated by descriptive outcomes including number of completed studies and glycemic control.

3.2 Eligibility. Participants will be recruited from the Diabetes Registry at the Benaroya Research Institute. Eligibile participants may enroll in the HCL, the FACL, or both studies.

HCL Study visit, Day 1 (~7 hours total): The below times are approximate and may be adjusted to accommodate the CRC schedule. Prior to arrival at the CRC, participants will be asked to eat their normal breakfast and take their usual amount of insulin based on BG and carbohydrate content before 8am. Once at the CRC, participants will be able to drink water ad lib, but no food other than the prescribed meals can be eaten, unless hypoglycemia intervention is necessary. Participants will be required to check FSBG before the meal and calibrate if the FSBG value varies by >30% from CGM value.

FACL Study visit, Day 1 (~ 23 hours total): The below times are approximate and may be adjusted to accommodate the CRC schedule. Prior to arrival at the CRC, participants will be asked to eat their normal breakfast and take their usual amount of insulin based on BG and carbohydrate content before 8 am. Once arrived at the CRC, participants will be able to drink water, but no food other than the prescribed meals can be eaten, unless hypoglycemia intervention is necessary. Participants will be required to check FSBG before meals, at bedtime and at 0300. They will calibrate if the FSBG value varies by >30% from the CGM value. They will calibrate the CGM every 12 hours as recommended by Dexcom.

Inclusion Criteria:

• Participants must have type 1 diabetes for greater than 1 year
• Have a hemoglobin A1c less than 9.0%
• Participants in the FACL arm must report that they engage in aerobic exercise at least 30 minutes three times weekly
• If participants in the FACL arm are age >35 OR duration of T1D >15 years OR history of T1D complications (proliferative retinopathy, nephropathy, peripheral vascular disease, autonomic neuropathy), participant must have EKG within normal limits obtained within last 6 months of study date
• Age 18-70
• Fluent and literate in English
• Use of an insulin pump for ≥ 3 months
• Use of a CGM/sensor for ≥ 5 days/week for ≥3 months
• Must have a diabetes care provider
• Use of an effective birth control method for women who are sexually active and of childbearing potential
• Willing and able to give informed consent

Exclusion Criteria:

• History of ≥ 1 episode of severe hypoglycemia (defined as hypoglycemia leading to loss of consciousness, seizure, or requiring assistance) in the previous 6 months

• History of ≥ 1 episode of DKA in the previous 6 months

• History of cardiovascular disease, characterized by any of the following:

  • Prolonged QT or arrhythmia
  • History of myocardial infarction within the past 6 months
  • History of ischemia on functional cardiac exam within the last year
  • History of left ventricular ejection fraction < 30%

• Uncontrolled hypertension (SBP > 160 mmHg or DBP > 100 mmHg)

• Current use of a beta blocker

• Stage 3 or greater renal disease

• Untreated thyroid disease

• History of substance abuse

• Current or previous use of medications for control of a seizure disorder

• Enrolled in another clinical trial in which they received investigational drug in the last 12 weeks

• Inability to comply with protocol

• Pregnant or breast feeding

• Use of medications other than insulin to control glucose

• Chronic corticosteroid use

• Pre-existing medical conditions deemed by study investigator to interfere with the study or increase risks of study participation.