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 (MAO) inhibitors,
• Non-selective systemic beta-blockers,
• Growth hormone,
• Thyroid hormones, unless use has been stable during the past 3 months
• SGLT2 inhibitors
• Participant has significant history of any of the following, that in the opinion of the investigator would compromise the participant's safety or successful study participation:

• Alcoholism,
• Drug abuse
• Significant acute or chronic illness, that in the investigator's opinion, might interfere with participant safety or integrity of study results
• Planned operation, MRI or CT which require removal of infusion set or CGM sensor during wear periods
• Current treatment with systemic (oral or IV) corticosteroids, monoamine oxidase (MAO) inhibitors, non-selective beta-blockers, growth hormone, herbal products that, in the opinion of the investigator, may alter insulin sensitivity or confer undue risk to the participant's participation in the study or non-routine vitamins. Furthermore, thyroid hormones are not allowed unless the use of these has been stable during the past 3 months.
• Current participation in another clinical drug or device study
• Inability of the participant to comply with all study procedures or to understand the participant instructions