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: 1. Participants are 18 - 70 years of age inclusive 2. Participant is in generally good health, as determined by the investigator 3. Participant is willing and able to individually complete written informed consent and agrees to comply with all study related testing and examinations 4. 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 5. Participant has been diagnosed with T1DM for at least 12 months 6. C-peptide \<0.6 nmol/L at screening 7. 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. 8. Participant can provide a minimum of 14 days of insulin pump data to demonstrate pump use compliance 9. 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. 10. 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 11. Participant has BMI in the range 20 - 35 kg/m2 inclusive 12. Participant has experience infusing a rapid-acting insulin analog for at least 6 months 13. 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. 14. Participant has ability to understand and comply with protocol procedures and to provide informed consent 15. HbA1c ≤8.5% 16. 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: 1. 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) 2. Participants who routinely change their commercial insulin infusion sets on average less often than every 4.5 days 3. Female participant is pregnant or nursing 4. Participant has abnormal skin at intended device infusion sites (existing infection, inflammation, burns, or other extensive scarring) 5. Participant has hemoglobin \<12.0 g/dL or potassium \< 3.5 milliequivalent/L at screening 6. 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. 7. Participant has a history of diabetic ketoacidosis in the last 6 months 8. Participant has known cardiovascular disease considered to be clinically relevant by the investigator 9. Participant has known arrhythmias considered to be clinically relevant by the investigator 10. Participant has known history of: 1. Cushing's Disease, 2. Pancreatic islet cell tumor, or 3. Insulinoma 11. Participant has: 1. Lipodystrophy, 2. Extensive lipohypertrophy, as assessed by the investigator 12. Participant is undergoing current treatment with: 1. Systemic oral or intravenous corticosteroids, 2. Monoamine oxidase (MAO) inhibitors, 3. Non-selective systemic beta-blockers, 4. Growth hormone, 5. Thyroid hormones, unless use has been stable during the past 3 months 6. SGLT2 inhibitors 13. 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: 1. Alcoholism, 2. Drug abuse 14. Significant acute or chronic illness, that in the investigator's opinion, might interfere with participant safety or integrity of study results 15. Planned operation, MRI or CT which require removal of infusion set or CGM sensor during wear periods 16. 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. 17. Current participation in another clinical drug or device study 18. Inability of the participant to comply with all study procedures or to understand the participant instructions