Pharmacokinetics (PK)/ Pharmacodynamics (PD) of an Extended Wear Infusion Set for Continuous Subcutaneous Insulin Infusion (CSII) in Type 1 Diabetes Mellitus (T1DM) Patients ("PEXIS")

Inclusion Criteria

In order to be eligible to participate in this study, an individual must meet all of the following criteria:

• Participants are 18 - 70 years of age inclusive
• Participant is in generally good health, as determined by the investigator
• Participant is willing and able to individually complete written informed consent and agrees to comply with all study related testing and examinations
• Participant must be geographically stable (e.g., expects to be available and capable of returning for all study specified test and examinations) during the study period
• Participant has been diagnosed with T1DM for at least 12 months
• C-peptide <0.6 nmol/L at screening
• Participant has been using insulin pump therapy for at least 6 months and is currently using a Medtronic MiniMed pump, model series 530 or higher. Use of 670G in auto mode is acceptable.
• Participant can provide a minimum of 14 days of insulin pump data to demonstrate pump use compliance
• Participant is willing to perform frequent (4 times per day or more) self-monitoring of blood glucose (SMBG), including before meals and before bed, and using a meter and test strips provided by the sponsor during the two weeks of active treatment. This includes participants who are currently using real-time continuous glucose monitoring and may continue to do so, but must also collect SMBG values as instructed.
• Participant is willing to perform serum ketone measurements whenever the blood glucose is determined to be greater than 250 mg/dL after extended fasting (e.g. overnight or more than five hours after a meal) using a ketone meter and strips provided by the sponsor
• Participant has BMI in the range 20 - 35 kg/m2 inclusive
• Participant has experience infusing a rapid-acting insulin analog for at least 6 months
• Participant has been using or is willing to use a Continuous Glucose Monitor (CGM) (reading data available for at least 80% of time for a week of data collection during the screening period). Participants already using - Dexcom G6 real time CGM may continue to use their own CGM unit; participants not using the G6 will be provided with a G6 monitor. All participants will be provided with CGM disposables for use during the treatment period.
• Participant has ability to understand and comply with protocol procedures and to provide informed consent
• HbA1c ≤8.5%
• Stable body weight in the 3 months prior to enrollment (change in body weight <5%)

Exclusion Criteria

An individual who meets any of the following criteria will be excluded from participation in this study:

• Participants whose average total daily insulin dose exceeds 85 units/day (i.e., typically change insulin reservoirs more often than every 4 days on average)
• Participants who routinely change their commercial insulin infusion sets on average less often than every 4.5 days
• Female participant is pregnant or nursing
• Participant has abnormal skin at intended device infusion sites (existing infection, inflammation, burns, or other extensive scarring)
• Participant has hemoglobin <12.0 g/dL or potassium < 3.5 milliequivalent/L at screening
• Participant has documented history in last 6 months of severe hypoglycemia associated with cognitive dysfunction sufficiently severe to require third party intervention or a history of impaired awareness of hypoglycemia.
• Participant has a history of diabetic ketoacidosis in the last 6 months
• Participant has known cardiovascular disease considered to be clinically relevant by the investigator
• Participant has known arrhythmias considered to be clinically relevant by the investigator
• Participant has known history of:
• Cushing's Disease,
• Pancreatic islet cell tumor, or
• Insulinoma
• Participant has:
• Lipodystrophy,
• Extensive lipohypertrophy, as assessed by the investigator
• Participant is undergoing current treatment with:
• Systemic oral or intravenous corticosteroids,
• Monoamine oxidase (